Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

To elucidate the molecular weight (M-w) dependence of the growth rate of spherulite (G) of cyclic polymers polymerized by the ring expansion reaction, we studied the G of cyclic poly(epsilon-caprolactone) (C-PCL) growing from the melt as a function of the crystallization temperature (T-c) and degree of supercooling (Delta T) using polarizing optical microscopy. We prepared C-PCLs comprising an exclusively repeating unit, excluding other structural units with M-w = 17000, 33000, 41000, 74000 and 85000 and linear PCLs (L-PCL) with M-w = 16000, 35000 and 60000, where M-w was determined by GPC using linear polystyrene standards.G obeyed the equation, G = G(0)exp(-B/T Delta T), for all the samples. The activation energies of secondary nucleation (B) of C-PCL were almost identical except for the C-PCL with the lowest M-w. Since B is proportional to the end surface free energy of the secondary nucleus, it implies that the regularity of the folding surface of C-PCL with high M-w is independent of M-w.Compared to C-PCL and L-PCL having almost the same M-w, G of L-PCL is higher than that of C-PCL at the same T Delta T. This suggests that G of C-PCL and L-PCL is not solely controlled by the entanglement because the entanglement of C-PCL is lower than that of L-PCL. We found the following associations: G(0)alpha M-w(-1.2) for C-PCL and G(0)alpha M-w(-0.67) for L-PCL. The difference in the power of the G(0) dependence on M-w reflects the difficulty of performing sliding diffusion in the secondary nucleus. This strongly supports the hypothesis that the absorption behavior of C-PCL chains in the secondary nucleus on the growth front is significantly different from that of L-PCL.

DOI： 10.1016/j.polymer.2020.122403

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Size control of the poly (1,4-phenylene-5-hydroxyisophthalamide) hollow spheres was examined by tuning the polymerization condition, focusing on concentration, temperature and solvent. Higher concentration lowered the diameter owing to the higher degree of super-saturation for nucleation. Temperature drop during the polymerization just before the nucleation was so effective to make the diameter smaller. Moreover, the diameter was susceptive to the solubility of oligomers in the solvent, and higher content of liquid paraffin in the aromatic solvent lowered the solubility, resulting in the decrease in the diameter. Based on these results, the combination of the temperature drop and the solvent effect was the most desirable to prepare the smallest hollow spheres, and the diameter of hollow spheres could be controlled from 4.4 to 0.7 mu m. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2017.01.060

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS LTD  

Crystals of salt monomer prepared from aromatic tetracarboxylic acids and aromatic diamines were polymerized at 220 degrees C for 3 h and at 400 degrees C for 3 h under argon flow. Highly crystalline polyimide particles having clear morphology were obtained with good yield. They were lozenge-like crystals, long plate-like crystals, fibrillar crystals, and spherical aggregates of plate-like crystals. The crystals of salt monomer were polymerized in the solid-state with maintaining the morphology, and therefore the morphology of the polyimide particles were the same to that of the crystals of the corresponding salt monomer. Molecular orientation in the lozenge-shaped crystal of poly(p-phenylene pyromelliteimide) was examined by selected area electron diffraction, and the polymer molecules aligned perpendicular to the plate plane which was the direction of the thickness. Obtained particles possessed good thermal stability.

DOI： 10.1177/0954008315619998

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

From the viewpoint of the suppression of the petroleum consumption, aromatic poly(ether ketone)s (PEKs) were prepared by the nucleophilic aromatic substitution polymerization of 2,5-bis(4-fluorobenzoyl)furan (BFBF) synthesized from biomass and aromatic bisphenols. The model reaction of BFBF and p-methoxyphenol revealed that BFBF possessed enough reactivity for the nucleophilic aromatic substitution reactions. The polymerizations of BFBF and aromatic bisphenols afforded high molecular weight polymers with good yields in N-methylpyrrolidone and diphenyl sulfone for several hours. The longer polymerization time brought about the formation of insoluble parts in any solvents and reduction of molecular weight. The obtained PEKs were thermoplastics and exhibited good thermal stability, mechanical properties, and chemical resistance comparable to common high-performance polymers. The thermal properties were tunable with the structure of bisphenols. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3094-3101

DOI： 10.1002/pola.28193

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Preparation of poly[4-(5-oxy-1,3-dioxoisoindoline-2-yl)benzoyl] (PODB) crystals, which was an intractable aromatic poly(ester-imide), was examined by means of reaction-induced crystallization of oligomers during the polymerization. Highly crystalline PODB helical ribbons were obtained by the polymerization of N-(4-carboxyphenyl)-4-acetoxyphthalimide in aromatic solvent at 280-330 degrees C at a concentration of 0.5-1.0%. The PODB molecules aligned along the long axis of the helical ribbon. The pitch of the helix increased with the polymerization temperature and it could be controlled from 320 nm to 1.3 mu m. Further, the fibrillar PODB crystals comprised of the helical and the non-helical blocks were prepared by the on-off switching of the helical morphology with the changing the temperature and the concentration of the polymerization. These results provided the methodology for the morphology control of polymer crystals. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2016.06.055

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Aromatic poly(ether ketone)s were synthesized by the Friedel Crafts polymerization of 2,5-furandicarbonyl dichloride prepared from biomass and petroleum-based aromatic ethers such as diphenyl ether and 1,4-diphenoxybenzene with aluminum chloride (AlCl3). The polymerizations in common molecular solvents such as 1,2-dichloroethane and nitrobenzene did not afford polymers. The Friedel-Crafts polymerization usually undergoes in the swollen gel of the oligomer-AlCl3 complexes; the precipitated physical gels had not been enough swollen. The polymerizations were carried out in various ionic liquids to form swollen gels. The polymerizations proceeded in specific ionic liquid such as 1-butyl-3-methylimidazolium chloride ([C(4)min] CO, and high molecular weight polymers were obtained with good yield. The gels formed in [C(4)mim] Cl were more highly swollen, and additionally the rate constant estimated by the model reaction of 2,5-furandicarbonyl dichloride and anisole was higher in [C4(m)im]Cl than that in 1,2-dichloroethane. The obtained poly(ether ketone)s exhibited good thermal stability and chemical resistance comparable to common poly(ether ketone)s.

DOI： 10.1021/acs.macromol.5b02788

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC FIBER SCIENCE TECHNOLOGY  

One-pot preparation of poly[ 4-(5-oxy-1,3-dioxoisoindolin-2-yl) benzoyl] (PODB) crystals which was an aromatic poly(ester-imide) was examined by means of the reaction-induced crystallization during polymerization of 4-acetoxyphthalic anhydride (APA) and 4-aminobenzoic acid (AmBA). Two-step heating program was suitable for the formation of PODB crystals. The reaction of APA and AmBA at 150 degrees C, which was much lower than the polymerization temperature, was of importance to synthesize N-(4-carboxyphenyl)-4-acetoxyphthalimide. Even though the amide moiety was incorporated, the PODB crystals were formed as precipitates by heating at 150 degrees C and then at 280-350 degrees C. Morphology of PODB depended on the polymerization conditions and fibrillar crystals, rod-like crystals and ribbon-like crystals were obtained. This result provided a novel one-pot procedure for the control of the PODB morphology.

DOI： 10.2115/fiberst.2016-0008

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Aromatic polyesters were synthesized by the polymerization of bio-based 2,5-furandicarboxylic acid (FDCA) with petroleum-based 1,3-and 1,4-diacetoxybenzene (DAB) from the viewpoint of the suppression of the petroleum consumption to develop the sustainable development society. Polyesters prepared at the molar ratio of 1,4-DAB in DAB (chi) of less than 60 mol% showed meltability under decomposition temperature. When the value of chi was 20-60 mol%, the polyesters exhibited optical anisotropicity in melt phase, suggesting the thermotropic liquid crystallinity. The phase transition temperature of these polyesters depended on the composition and it was tunable by the. value. The film of the polyesters prepared at. of 20 mol% possessed 1.2 GPa of the modulus, 26.0 MPa and 2.9% of the strength and elongation at break, respectively. Polyesters based on FDCA possessed good thermal stability and mechanical properties comparable to common aromatic polyesters.

DOI： 10.2115/fiberst.2016-0009

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TECHNICAL ASSOC PHOTOPOLYMERS,JAPAN  

The Friedel-Crafts polymerization of 2,5-thiophenedicarbonyl dichloride and diphenyl ether in 1,2-dichloroethane afforded only low molecular weight of poly(ether ketone) containing thiophene-ring. In contrast to this, the polymerization in 1-butyl-3-methylimidazolium chloride-aluminum chloride mixture gave high molecular weight polymers. The polymerizations in ionic liquids were a new approach to expand possibility of polymer synthesis such as preparation of polymer containing heterocyclic rings. The obtained poly(ether ketone) exhibited good thermal stability and chemical resistance comparable to common poly(ether ketone)s.

DOI： 10.2494/photopolymer.29.243

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Helical ribbons of poly[4-(5-oxy-1,3-dioxoisoindoline-2-yl) benzoyl] (PODB) were previously prepared by the homo-polymerization of N-(4-carboxyphenyl)-4-acetoxyphthalimide (CAP) in aromatic solvents. The copolymerization of CAP and p-acetoxybenzoic acid (ABA) was examined to change the helical morphology. The helical morphology was extinguished by the copolymerization of a small amount of ABA at 280 degrees C at a concentration of 1.0% in aromatic solvent. Based on these results, ABA was added stepwise during the homo-polymerization of CAP. When a small amount of ABA was added, copolymer crystals comprised of helical and non-helical blocks were formed. The non-helical blocks grew on the PODB helical ribbons by the precipitation of co-oligomers. This result provides a novel method to control helical morphology by copolymerization.

DOI： 10.1039/c6ra22494f

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

DOI： 10.1002/pola.27791

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Hollow spheres of poly(1,4-phenylene-5-hydroxyisophthalamide) had been obtained by the reaction-induced phase separation during polymerization of 5-hydroxyisophthalic acid and 1,4-phenylene diamine in an aromatic solvent. In this study, formation mechanism of the hollow spheres was considered from the view points of eliminated small molecules, polymer structure, and cross-linking reaction. With respect to the eliminated small molecules, water was the most desirable to form gas-bubbles in droplets compared with methanol and acetic acid, due to the insolubility into the polymerization system. Rigid polymer structure was also needed to prepare hollow spheres owing to the rapid solidification of droplets. Further, phenolic hydroxyl group in 5-hydroxy-1,3-phenylene moiety caused the ester-amide exchange reaction to form cross-linked skin layer in the droplets. The efficient formation of the skin layer was important to encapsulate gas-bubbles in the droplets, resulting in the formation of hollow structure. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1966-1974

DOI： 10.1002/pola.27683

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Direct polymerizations of p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA) in the presence of boronic anhydride were examined by using crystallization under non-stoichiometric condition. The polymerizations were carried out with the addition of monofunctional compounds such as an aromatic carboxylic acid and a phenol. High molecular weight poly(p-oxybenzoyl) (PUB) and poly(2-oxy-6-naphthoyl) (PUN) were obtained in the form of precipitates, and their molecular weights were much higher than those calculated according to the stoichiometric imbalance. Oligomers were formed by the direct polymerization with eliminating water in the solution, and then they were precipitated to form the crystals at the initial stage of the polymerization. Oligomers end-capped by monofunctional compounds were also formed in the solution, but the polymerization continued with the elimination of monofunctional compounds by the ester exchange reaction. The end-capped oligomers were precipitated in the middle of the polymerization, and the polymerization proceeded efficiently even in the precipitated crystals by not only the direct polymerization but also the ester exchange polymerization, resulting in the increase in molecular weight. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2015.04.019

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Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC POLYMER SCIENCE JAPAN  

In order to clarify the effects of multiple hydrogen bonds between chain ends on the crystal growth of polymers, we studied the growth rate of crystal G of polyethylene (PE) having amino groups and thymine units in the terminal (PE-Thym) and polydioxanone having hydroxy groups and thymine units in the terminal (PDX-Thym) from the melt as a function of the degree of supercooling Delta T by means of polarizing optical microscope, DSC and WAXS. PE-Thym and PDX-Thym have multiple hydrogen bonds between their terminals. We also prepared PE having amino and hydroxy groups in the terminal (PE-OH) and PDX having carboxy and hydroxy groups in the terminal (PDX-OH) as reference samples. Those show weak single hydrogen bond between their terminals. Number average molecular weights M-n of PE-Thym and PE-OH are almost the same (M-n = ca. 2000). M-n of PDX-Thym and PDX-OH are 3000 and 5600, respectively. G of all the samples obeyed the equation, G = G(0) exp(B/Delta T). The exponent B for PE-Thym and PDX-Thym is almost the same as for PE-OH and PDX-OH. Since B is proportional to the surface free energy of the end surface of the nucleus, this indicates that the regularity of folding at the surface is also the same. On the other hand, G(0) of PE-Thym and PDX-Thym is much less than that of PE-OH and PDX-OH. We speculate that the reeling motion from the melt to the nucleus during crystal growth is suppressed due to the formation of a dynamic multiple-hydrogen-bond network between chain ends in the melt. Moreover, in order to shield the multiple hydrogen bonds in the terminal, we studied the Delta T dependence of G for PDX-Thym with added adenine. Compared to PDX-Thym without added adenine, we found that the Delta T dependence of G changed. This indicates that the influence of hydrogen bonds on crystal growth is closely related with the regime of crystal growth.

DOI： 10.1295/koron.71.562

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Composition control of aromatic poly(thioester-amide) was examined by the reaction-induced phase separation during polymerization of S-acetyl-4-mercaptobenzoic acid (AMBA) and p-acetylaminobenzoic acid (AABA) in aromatic solvent. The poly(thioester-amide)s were obtained as precipitates and their yields became lower at the middle range of the content of AMBA in feed ((f)). The contents of p-mercaptobenzoyl (MB) moiety ((p)) in the precipitates prepared without shearing were in good agreement with the (f) values. In contrast to this, the (p) values of the precipitates prepared at (f) of 50-70 mol % under shearing were much lower than the (f) values. The reaction rate of AMBA increased with shearing, whereas that of AABA was unchanged by shearing. This shearing effect on the reaction rates accelerated to form the homo-oligomers. The solubility of MB oligomers enhanced by shearing, whereas that of p-benzamide oligomers did not enhance owing to the strong interaction through hydrogen bonding. The MB oligomers were inhibited to be precipitated, resulting in the lower (p) values than the (f) values. The composition could be controlled by the application of the shearing to the heterogeneous polymerization. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4301-4308

DOI： 10.1002/pola.26839

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Language：English   Publishing type：Research paper (international conference proceedings)  

Poly(2,6-1H-benzo[f]isoindole-1,3(2H)-dione) (PBID), which was a self-condensable naphthalene-containing polyimide, was synthesized as precipitated crystals from 6-amino-3-(ethoxycarbonyl)-2-naphthoic acid and 7-amino-3-(ethoxycarbonyl)-2-naphthoic acid by using reaction-induced crystallization during solution polymerization. The obtained PBID crystals possessed high crystallinity, excellent thermal stability and chemical resistance. They neither exhibited Tg nor Tm under the decomposition temperature. The morphology of the PBID crystals depended on not only the polymerization conditions but also the isomeric structure of the monomer, and the wide variety of the morphology appeared such as rods, plates and lathes. The plate-like crystals had fine protuberances on the surface. Copolymerization of PBID and poly(4-phthalimide) were also examined. © 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.eurpolymj.2013.05.021

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Poly(p-oxybenzoyl) (POB) precipitates prepared by reaction-induced phase separation during copolymerization exhibit wide variety of morphologies such as fibril, needle, slab, spindle, and sphere. The morphology is significantly influenced by the copolymerization conditions of structure of trifunctional comonomers, copolymerization ratio, solvent, concentration, and temperature of the polymerization. Among them, POB nanofiber networks like a texture of nonwoven fabrics are obtained only by the polymerization of 4-acetoxybenzoic acid with 3,5-diacetoxybenzoic acid (DABA) in aromatic solvent at a concentration of 1.0-2.0% at the content of DABA in feed of 10-20 mol % at 320°C. The network is comprised of fibrillar crystals connected each other at spherical nodal points. The diameters of the fibers are 90-129 nm. This network is highly crystalline and the molecules are aligned along the long direction of the fibers. Various parameters characterized the networks can be controlled by the polymerization concentration. © 2012 Wiley Periodicals, Inc.

DOI： 10.1002/app.38554

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Hollow spheres of aromatic polyamide are obtained by the reaction-induced phase separation during polymerization of 5-hydroxyisophthalic acid and 1,4-phenylene diamine in an aromatic solvent at a concentration of 1-2% at 320 degrees C without stirring. The hollow sphere has a dimple hole and the diameters of the hollow spheres are 3-4 mu m. The droplets are initially generated via liquid-liquid phase separation and then rigid crosslinked network structure formed the rigid skin layer on the surface of the droplets. The solidification of the droplets occurred owing to the further polymerization in them with maintaining the morphology to form the hollow spheres. The hollow spheres exhibit outstanding thermal stability. (C) 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 780-785

DOI： 10.1002/pola.26467

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TECHNICAL ASSOC PHOTOPOLYMERS,JAPAN  

DOI： 10.2494/photopolymer.26.341

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Morphology control of poly(ether ketone) (PEK) was examined by using the crystallization during the nucleophilic aromatic substitution reaction of potassium salt of 4-fluoro-4'-hydroxybenzophenone. Polymerizations were carried out at 290 degrees C. The PEK was obtained as precipitates and its morphology was highly influenced by the polymerization condition such as the solvent, the concentration and the polymerization time. High crystalline spindle-like crystals were obtained by the polymerization in diphenyl sulfone (DPS) at a concentration of 5.0% for 2 h with the yield of 86%. The average length and width were 1.4 mu m and 300 nm respectively, and the maximum thickness was 130 nm. The surface was not smooth and it was hilly. The spindle-like crystal was likely consisted of multilayered lamellae comprised of the microcrystallites. The molecules were oriented perpendicular to the lamella. The polymerization in DPS at a higher concentration of 10.0% afforded the networks of nanofibres, of which the diameter was 100-250 nm. The obtained PEK precipitates possessed excellent thermal properties. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.eurpolymj.2012.07.004

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Morphosynthesis of poly[4-(1,4-phenylene)oxyphthalimide] (POPI) and poly[4-(1,4-phenylene)oxyphthalimide-co-4-phthalimide] (POPI-PPI) was examined by using the crystallization during the polymerization. The POPI fibrillar crystals were obtained as precipitates with the formation of spherical aggregates of plate-like crystals. Some of the POPI fibrillar crystals were longer than 15 mu m. They possessed high crystallinity and the molecules aligned perpendicular to the long direction of the fibers. On the other hand, one-dimensional structures of POPI-PPI such as ribbon, cone, rod, and fiber were obtained as precipitates by the copolymerization. The copolymer molecules might align along the long direction of the cone-like crystals. The morphology of these poly(ether-imide)s could be controlled by not only the polymerization condition but also with the aid of copolymerization. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

DOI： 10.1002/polb.23122

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The influence of shear flow, especially the timing for the application of shearing, was examined to enhance the selectivity for the preparation of poly(p-oxybenzoyl) (Pp-OB) by using hydrodynamically induced phase separation during polymerization of 4-(4-acetoxybenzoyloxy) benzoic acid (p-ABAD) and m-acetoxybenzoic acid (m-ABA). The polymers containing few m-oxybenzoyl (m-OB) moieties were obtained as precipitates even at high content of m-OB moiety in feed (chi(f)) under shear flow. The content of m-OB moiety in the precipitates (chi(p)) prepared under shearing throughout the polymerization at the shear rate (gamma) of 489 s(-1) was 6.3 mol % even at chi(f) of 60 mol %. Especially, the Pp-OB was obtained as the precipitates at chi(f) of less than 50 mol %. The timing of the application of the shearing influenced the selectivity significantly, and the shearing just after the precipitation of the oligomers started was quite efficient to enhance the selectivity more. The chi(p) of the precipitates prepared with shearing at gamma of 489 s(-1) just after the precipitation was only 3.9 mol % even at chi(f) of 60 mol %. The shear flow reduced the difference in the reactivity between p-ABAD and m-ABA, resulting in the decrease in the selectivity with regard to the formation of p-oxybenzoyl homo-oligomer. However, the shear flow enhanced the difference in the miscibility between homo-oligomers and co-oligomers. This change in the miscibility by shear flow brought about the more rapid precipitation of homo-oligomers, leading to the enhancement of the selectivity. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 4613-4617, 2011

DOI： 10.1002/pola.24904

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Authorship：Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC POLYMER SCIENCE JAPAN  

In order to clarity tne effects ot entanglement species on nucleation ot polymers, we stuaiea tne growtn rate ot spneruute G of cyclic ana linear polyethylenes (C-PE and L-PE) from the melt as a function of degree of supercooling A T by means of polarizing optical microscope. We prepared several C-PEs with different weight average molecular weights M w=9300, 43600 and 86500, and L-PE with A/,=44000. G of all the sample were obeyed the equation, G = G 0 exp (-B/△T).BoîC-PE gradually increased with increasingM w. B is proportional to the surface free energy of the end surface of the nucleus, and this indicates that the regularity of folding surface increased with increasing M w. We consider that topological constraint of cyclic polymer becomes large with decreasing M., of the cyclic polymer. On the other hand, for C-PE and L-PE having almost the same M w (=44 k), G 0 of C-PE is much less than that of L-PE. Due to the topological constraint of cyclic polymer, we speculated that the adsorption mode on the crystal surface of C-PE is different than that of L-PE. ©2011, The Society of Polymer Science, Japan.

DOI： 10.1295/koron.68.694

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Morphology of four kinds of aromatic polyimidazoles was examined by using reaction-induced crystallization during solution polymerization at a concentration of 1% at 350 degrees C in liquid paraffin (LPF), dibenzyltoluene (DBT), and the mixture of these solvents. Aggregates of ribbon-like crystals of poly[2,6-(2,6-naphthalene)-benzobisimidazole] were obtained in LPF, and those of plate-like crystals were obtained in DBT/LPF-50 and in DBT. In contrast to this, the network structures of poly[2,2'-(2,6-naphthalene)-5,5'-bibenzimidazole)] (PNT-BBI) nanofibers with the diameter of 25 to 90 nm was mainly obtained in DBT. The network structures of the PNT-BBI nanofibers could be recognized as nonwoven fabrics of the high-performance polymers. Imidazole trimers were precipitated to form the ribbon-like crystals and then they were continuously supplied from solution to grow the crystals. Molecular weight increased by the polymerization on the surface of the crystals when they crystallized and in the crystals. The initially formed aggregates of ribbon-like crystals changed to the nanofibers with time. In the case of poly[2,6-(4,4'-biphenylene)-benzobisimidazole] and poly[2,2'-(4,4'-biphenylene)-5,5'-bibenzimidazole)], they exhibited various morphologies such as spheres, lath-like crystals, and the spherical aggregates of lath-like crystals depending on the solvent, but fibers like PNT-BBI were not formed. The crystals obtained in this study possessed very high crystallinity and the outstanding thermal stability measured by TGA. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2851-2860, 2011

DOI： 10.1002/app.33914

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Poly(p-oxybenzoyl) (POB) crystals were prepared by reaction-induced crystallization during direct polymerization of p-hydroxybenzoic acid in the presence of boronic anhydrides. Polymerizations were carried out at 300 degrees C in dibenzyltoluene at a concentration of 1% with three kinds of anhydrides of boronic acid such as 3,4,5-trifluorophenylboronic acid (TFB), 4-methoxyphenylboronic acid (MPB) and 4-biphenylboronic acid (BPB). The POB crystals were formed as precipitates in the solution and the morphology was considerably influenced by both the structure of the boronic anhydride and its concentration (C(B)). Needle-like crystals were firmed in the presence of TFB anhydride (TFBA) at C(B)S of 5 and 10 mol % by the spiral growth of lamellae. Spherical aggregates of slab-like crystals were formed at C(B)S from 50 to 100 mol %. The polymerization with MPB anhydride and BPB anhydride (BPBA) also yielded the needle-like crystals at C(B)S of 50 and 5 mol %, respectively. The polymerization with TFBA at lower C(B) was favorable to prepare the needle-like crystal. Molecular weight was also influenced by the structure of the boronic anhydride and C(B). M(n) increased generally with C(B) and BPBA gave the highest M(n) of 14.7 x 10(3) at C(B) of 100 mol %. The loose packing of the molecules in the crystal caused by the bulkiness of the end-groups made the polymerization in the crystals more efficiently. Morphology and molecular weight of the POB crystals could be controlled by the chemical structure and the content of boronic anhydride. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1088-1096, 2011

DOI： 10.1002/pola.24521

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Morphology control of poly(p-phenylene pyromelliteimide) (PPPI) crystals was examined using reaction-induced crystallization of oligomers during solution polymerization of self-polymerizable N-(4'-aminophenyl)-3-carboxyl-4-alkoxycarbonylPhthalimide. Micro-flowers of the PPP1 needle-like crystals were formed in which the needle-like crystals grew radially from the center part as petals. The molecules aligned regularly along the long axis of the needle-like crystal. The structure of alkoxy group in the monomer and the monomer concentration influenced the size of the needle-like crystals, and their average length and width were changeable from 640 nm to 1.69 mu m and from 110 nm to 210 nm, respectively. The average thickness was 20 nm. The obtained micro-flowers possessed high crystallinity and exhibited excellent thermal stability. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2010.12.022

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL PUBLISHING, INC  

Polymerizations of 4-(4-acetoxybenzylideneamino)-benzoic acid were performed in dibenzyltoluene (DBT) and a mixture of DBT and liquid paraffin at 350 degrees C for 6 h. Fibrillar crystals of poly[4-(4-oxybenzylideneamino)benzoyl] (POAB) having the width of 50-450 nm and the length of over 15 pm were obtained by the crystallization during the polymerization. The fibrillar crystals possessed high crystallinity and the molecular chains aligned perpendicular to the long axis of the fibrillar crystals. Plate-like crystals were initially formed by the crystallization of oligomers, and then they changed to the fibrillar crystals via the formation of bundle-like crystals after 1 h. Molecular weight increased by the further polymerization in the crystals. Based on these results, one-pot preparation of the fibrillar POAB crystals was examined by the polymerization of 4-acetoxybenzaldehyde and 4-aminobenzoic acid. The polymerization at 180 degrees C for 2 h and then at 350 degrees C for 6 h afforded the fibrillar crystals with a small amount of the ribbon-like crystals. Although the side-reaction to generate the p-benzamide sequences was not completely depressed, the sequence of heating in which 180 degrees C for the formation of the azomethine linkage and then 350 degrees C for the formation of the ester linkage was preferable to prepare the fibrillar POAB crystals. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 127-137, 2011

DOI： 10.1002/pola.24427

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Preparation of discrete PPPI microspheres was examined using the crystallization of oligomers during isothermal polymerization of PMDA and p-phenylene diisocyanate, and that of pyromellitic dithioanhydride and PPDA in poor solvents. In contrast to PPPI microspheres with smooth surfaces that were previously prepared by phase-separation during the polymerization of PPDA and PMDA, the microspheres obtained here consisted of flake-like lamellae with rugged surfaces. The diameters of the microspheres ranged from 0.5 to 6.7 mu m. They exhibited excellent thermal stability depending on the monomers. These results provide a new preparative procedure of the PPPI microsphere with a rugged surface.

DOI： 10.1002/macp.201000510

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Poly(2-oxy-6-naphthoyl) (PON) was obtained as precipitates by direct polymerization of 2-hydroxy-6-naphthoic acid (HNA) in the presence of boronic anhydrides such as 2,4,6-tris(3,4,5-trifluorophenyl)-1,3,5,2,4,6-trioxatriborinane (TFBA) and 2,4,6-tri(biphenyl-4-yl)-1,3,5,2,4,6-trioxatriborinane (BPBA). The polymerizations were carried out in an aromatic solvent at 300 degrees C for 24 h. Both morphology and molecular weight of the PON precipitates were considerably influenced by not only the structure of the boronic anhydride but also its concentration (c(B)). Spheres with needles on their surface were formed in the polymerization with TFBA at c(B) of 50-70 mol%, and those having smooth surface were obtained at c(B) of 100 mol%. The M(n) increased with the value of c(B) in the range from 2.7 x 10(3) to 9.0 x 10(3). Aggregates of cone-like crystals were prepared in the polymerization with BPBA at c(B) of 10-30 mol%, and spheres having rugged surface were formed at c(B) of 50-100 mol%. The M(n) also increased with the value of c(B) in the range from 5.4 x 10(3) to 12.9 x 10(3). These PON precipitates possessed high crystallinity in spite of the morphology. The copolymerization of HNA and 4-hydroxybenzoic acid (HBA) was also examined in the presence of BPBA at c(B) of 100 mol% with varying the content of HBA in feed (r(f)). Copolymers were obtained as spheres of which the content of 4-oxybenzoyl moiety was lower than the value of r(f) due to the difference in the solubility of the oligomers.

DOI： 10.1039/c0py00420k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The preparation of poly[2,6-(1,4-phenylene)-benzobisimidazole] (PPBI) nanofibers was examined using the crystallization of oligomers during isothermal polymerization of self-polymerizable 2-(1,4-carbophenoxyphenyl)-5,6-diaminobenzimidazole. The polymerization was carried out at 350 degrees C at a concentration of 1w-t.-% for 6 h in three kinds of solvent. The solvent influenced the morphology of PPBI precipitates significantly, and PPBI nanofiber networks were successfully formed in DBT, of which the width ranged from 30 to 110 nm. Molecules were aligned along the long axis of nanofibers. A fibrillar morphology with molecular orientation is ideal for high performance materials such as reinforcements, non-woven fabrics and so on. The nanofiber networks exhibit the highest thermal stability.

DOI： 10.1002/macp.201000306

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Synthesis of poly[oxy-(2,3,5,6-tetrafluoro-1,4-phenylene)-(1,3,4-oxadiazol-2-yl)-1,4-phenylene] (F-PEOz) was examined by nucleophilic aromatic substitution reaction of 2-(4-hydroxyphenyl)-5-pentafluorophenyl-1,3,4-oxadiazole (HPOz). Only low molecular weight F-PEOz or crosslinked insoluble polymers were obtained by the solution polymerization with bases. In contrast, thermally induced solid-state polymerization of HPOz potassium salts at 180 degrees C for 1 h gave fully soluble F-PEOz with the yield of 84% and its reduced viscosity was 0.66 dL The longer polymerization time gave insoluble polymers due to the crosslinking reaction even in solid state. The solid-state polymerization did not undergo topochemically and it proceeded in an amorphous state. The crosslinking reaction was slightly inhibited by the solid-state polymerization. F-PEOz exhibited excellent solubility, high T(g) of 246 degrees C and good thermal stability. (c) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 91-98, 2010

DOI： 10.1002/app.32391

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Morphological control of poly(2,5-benzimidazole) (PBI) was examined by reaction-induced phase separation of oligomers during polymerization to prepare nanofibers. Three monomers, 3,4-diaminobenzoic acid (DABA), 3,4-diacetoamidebenzoic acid (DAcBA) and phenyl 3,4-diaminobenzoate (PDAB), were used to synthesize PBI. Polymerizations were carried out at 350 degrees C in a mixture of dibenzyltoluene isomers. Polymerization of DABA yielded spheres with plate-like crystals on their surface. Polymerization of DAcBA yielded almost no precipitates because of the high solubility of DAcBA oligomers. By contrast, polymerization of PDAB yielded aggregates of PBI nanofibers (of which the average diameter was similar to 60 nm), which resembled nonwoven fabrics. These fibers were formed by precipitation of (2,5-benzimidazole) oligomers and their subsequent polymerization into a developing crystal structure. The structure of the monomer significantly influenced the morphology of the PBI product, and PDAB was preferable for the preparation of PBI nanofibers. The temperature of 10% N-2 weight loss in these nanofibers was in the range of 634-644 degrees C and they were thermally stable. Polymer Journal (2010) 42, 375-382; doi:10.1038/pj.2010.20; published online 17 March 2010

DOI： 10.1038/pj.2010.20

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We found the formation of "shish-like" fibril crystals of aliphatic polyesters such as Poly(L-lactic acid) (PLLA), poly(epsilon-caprolactone) (PCL), poly(12-hydroxydodecanoic acid) (PHDA) and poly( 1 6-hydroxyhexadecanoic acid) (PHHA) from the sheared melt with shear rate (gamma) over dot = 5 s(-1) observed by polarizing optical microscope (POM). The melting temperature T(m)s of obtained fibril crystals of PLLA and PCL were higher than those of spherulites and were close to the equilibrium melting temperature T(m)(0). The small angle X-ray scattering (SAXS) patterns from the bulk sample including fibril crystals, small amount of unoriented small crystals and amorphous showed no peaks arose from the existence of long periods in fibril crystals. These are the evidence that the observed fibril crystals consist of assemblies of a lot of extended chain crystals (ECCs). We observed the morphology of moderately extracted single strand of fibril crystals at the magnification of POM by means of scanning electron microscope. We found that macroscopic fibril crystals of PLLA with diameter d = 10 mu m consist of the bundle structure of microscopic fibril crystals with d = 2 mu m. From POM observation of the formation of fibril crystals of PLLA and PCL. we showed phase diagrams of molecular weight M and crystallization temperature T(c) for the formation of fibril crystals. From these phase diagrams, we evaluated a critical M and T(c) for the formation of fibril crystals. Moreover, from the sequential melting and crystallization experiments, it was implied that the entanglement and transesterification play an important role on the formation of fibril crystals of aliphatic polyesters. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.eurpolymj.2009.09.003

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Language：Japanese  

DOI： 10.2115/fiber.66.P_237

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Direct synthesis of rigid-rod aromatic polyamides was studied without condensation reagents by using reaction-induced crystallization of oligomers during solution polymerization. Polymerizations of p-aminobenzoic acid were carried out in an aromatic solvent at a polymerization concentration of 20% at 350 degrees C. High molecular weight poly(p-benzamide) (PBA) was obtained in the form of plate-like crystals, and the highest molecular weight was 11.6 x 10(3). In this polymerization, the oligomers were formed in the solution by the condensation reaction with the elimination of water. When the molecular weight of oligomers exceeded the critical value, the oligomers were precipitated by crystallization via supersaturated state to form the plate-like crystals. The molecular weight increased by the polymerization between the oligomers on and in the crystals. Poly(p-phenylene isophthalamide) (PPIA) was also obtained in the form of plate-like crystals by the polymerization of p-phenylene diamine (PPDA) and isophthalic acid (IPA) under the same condition as that of PBA. These results exhibited the thermally direct synthesis of infusible aromatic polyamides. Sequential addition of monomers into this heterogeneous polymerization was examined to increase the molecular weight. In the step-growth polymerization, the addition of monomers into the homogeneous polymerization could not increase the molecular weight because it was determined by the extent of reaction and reshuffled by the transamidation reaction. However, the addition of PPDA and IPA during the polymerization resulted in the increase in the molecular weight of PPIA. This result gave possibly a novel procedure for the preparation of high molecular weight condensation-type polymers.

DOI： 10.1021/ma9009033

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC POLYMER SCIENCE JAPAN  

In order to proof the existence of a disentangling pathway of condensation polymers via transesterification, we measured the growth rate of spherulites (G) of poly(L-lactic acid) (PLLA) and poly (epsilon-caprolactone) (PCL) as a function of melt annealing time (Delta t) before isothermal crystallization. We prepared three PLLA samples by means of reaction induced crystallization of oligomers during polymerization. For the sample with unclear crystal habit, we found that G was almost constant at Delta t < 30 min, and then monotonically decreased with increasing Delta t. On the other hand, for the sample with clear crystal habit, we found that G monotonically decreased with increasing Delta t. For PCL prepared by bulk polymerization, we found that G shows a plateau at Delta t < 30 min for the samples with a melt annealing temperature of T(max) = 100 and 130 degrees C. However, it was found that G monotonically decreased at T(max) = 80 degrees C. From GPC measurements of PLLA and PCL after melt annealing, we confirmed that the molecular weight did not change and molecular weight distribution became broad. These imply that PLLA and PCL have a pathway of disentanglement within the melt via transesterification.

DOI： 10.1295/koron.66.475

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Preparation of poly(4'-oxy-4-biphenylcarbonyl) (POBP) needlelike crystals was examined by using reaction-induced crystallization of oligomers during copolymerization of 4-(4-aceloxypheilyl)benzoic acid (APBA) and 4-acetoxybenzoic acid (ABA). Polymerizations were carried out in aromatic solvent at various ABA molar ratios in feed (chi(f)). When they chi(f) was 20-10 mol %, starlike aggregates of needlelike crystals and fibrillated slablike crystals were separately formed, exhibiting similar morphology to poly(4-oxybenzoyl) and POPB crystals. 4-(Oxyphenyl)benzoyl (OPB) homo-oligomers and co-oligomers rich in OPB moiety were more rapidly precipitated due to the lower solubility, and the slablike crystals were formed. Afterward, 4-oxybenzoyl (013) homo-oligomers and the co-oligomers rich in OB moiety were precipitated to form spindlelike crystals. The OPB homo-oligomers and the co-oligomers rich in OPB moiety were continuously crystallized on both crystals due to the high degree of supersaturation. and the spindlelike crystals grew to the needlelike crystals mainly comprised of POBP. Copolymerization of 4-(4-acetoxybenzoyloxy)benzoic acid and APBA at chi(f) of 10 mol % yielded the needlelike crystals without coexisting fibrillated slablike crystals. This result provides a new methodology for morphology control with the aid of copolymerization.

DOI： 10.1021/ma800029n

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Poly[2,6-(1,4-phenylene)-benzobisimidazole] (PPBI) crystals were prepared by using reaction-induced crystallization of oligomers during solution polymerization of 1,2,4,5-tetraaminobenzene and diphenyl terephthalate. Polymerizations were carried out at a monomer concentration of 4.3 x 10(-2) mol L-1 at 350 degrees C for 6 h. Brush-like PPBI crystals were obtained in a mixture of structural isomers of dibenzyltoluene, in which many needle-like crystals came out vertically from the surface of the ribbon-like crystals. Average width and thickness of the ribbon-like crystals were 0.75 mu m and 0.11 mu m, respectively. And average length and diameter of the needle-like crystals were 0.36 mu m and 50 nm, respectively. The brush-like crystals possessed high crystallinity and exhibited good thermal resistance. The ribbon-like crystals were formed by the crystallization of imidazole oligomers at an initial stage of polymerization, and then the needle-like crystals grew from the surface of the ribbon-like crystals. Polymerization occurred on the crystals when the oligomers were crystallized, leading to the high molecular weight PPBI crystals. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2008.07.011

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC FIBER SCIENCE TECHNOLOGY  

Microspheres of poly(p-oxycinnamoyl) (POC) were obtained by the polymerization of (E)-4-acetoxycinnamic acid in aromatic solvent at 320 degrees C and a concentration of 1.5% without stirring via liquid-liquid phase separation of oligomers. In contrast to this, rod-like crystals were formed under shearing with more than 700 rpm. The obtained rod-like crystals were 10-15 mu m in length and 1.0-1.5 mu m in width having many thorns on the surface. The critical stirring speed for the onset of Taylor vortices was in agreement with 700 rpm and the crystallization of oligomers was hydrodynamically induced by the generation of Taylor vortices affording the rod-like crystals. Stirring influenced the morphology of POC significantly and this work provided a new procedure for the fabrication of fine fibers of intractable aromatic polymers.

DOI： 10.2115/fiber.64.220

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The morphology of poly(4-phthalimide) (PPI) crystals was examined by using reaction-induced crystallization of oligomers during solution polymerization. Polymerizations of alkyl 4-aminophthalates such as I-ethyl 4-aminophthalate (1EAP), 2-ethyl 4-aminophthalate, 1-hexyl 4-aminophthalate, and 2-hexyl 4-aminophthalate were carried out at 330 degrees C in a mixture of isomers of dibenzyltoluene without stirring. Nanoscale PPI ribbons having smooth surface were formed by the polymerizations of these monomers. The ribbons prepared from 1EAP at a concentration of 2.0% for 24 h were averagely 12 mu m in length, 150 urn in width, and 8 nm in thickness, in which the molecular chains aligned along the long axis of the ribbon. The phase-separated oligomers were fully cyclized imide oligomers, and this is of great importance for the formation of the ribbon. The obtained ribbons possessed high crystallinity and exhibited excellent thermal stability.

DOI： 10.1021/ma800874w

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Composition control of copolyester was examined by using hydrodynamically induced phase separation, during solution polymerization, of p-acetoxybenzoic acid and m-acetoxybenzoic acid (m-ABA). Polymerizations were carried out in liquid paraffin at 1.0% of concentration under shear flow. The polymers were obtained as precipitates formed via phase separation of oligomers and the subsequent polymerization in the precipitates. When the feed ratio of m-ABA (chi(f)) was 20 mol %, the molar ratio of m-oxybenzoyl moiety in the precipitated polymers (chi(p)) was 5.3, 3.1, and 2.3 mol % at a shear rate (gamma) of 0, 147, and 489 s(-1), respectively. The values of chi(p) were much lower than those of chi(f), and shear flow lowered the value of chi(p); thus, controlling shear flow influenced both the reaction rate of the monomers and the miscibility of the oligomers. It especially enhanced the difference on the miscibility between homo-oligomers and co-oligomers. This change in the miscibility by shear flow brought about the more rapid precipitation of homo-oligomers than co-oligomers, leading to the selective formation of poly(p-oxybenzoyl).

DOI： 10.1021/ma800529d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Morphology control of polybenzimidazoles was examined by reaction-induced phase separation during polymerization. Polymerizations of 3,3'-diaminobenzidine with terephthalic acid or diphenyl terephthalate were carried out in poor solvents. The morphology of the precipitated poly[2,2'-(1,4-phenylene)-5,5'-bibenzimidazole] (PpBBI) was significantly influenced by the polymerization conditions, and the aggregates of nano-scale PpBBl fibers were obtained by the polymerization at a concentration of 3-5% and 320-350 degrees C in dibenzyltoluene. The average diameter of the fibers was ca. 50 mn and inherent viscosities of the precipitates were 0.35-0.58 dL g(-1). They possessed high crystallinity and thermal stability. The oligomers were precipitated first by the reaction-induced crystallization to form the highly crystalline lath-like crystals at an initial stage of polymerization. Then the lath-like crystals were split into disentangled aggregates of fine fibers with maintaining the high crystallinity. The polymerization mainly proceeded when the oligomers were registered into the crystals. The obtained aggregates of nano-scale fibers could be recognized as nonwoven fabrics. Morphology control of poly [2,2'-(1,3-phenylene)-5,5'-bibenzimidazole] was also examined and particles were mainly formed. (c) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2008.02.016

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Poly(aryl thioether)s (F-PTEs) containing 2,3,5,6-tetrafluoro-1,4-phenylene moiety and polar moiety, such as 1,3,4-ozadiazole, ether ketone, and amide groups, were synthesized by nucleophilic aromatic substitution reaction of aryl fluorides and 4,4'-thiobisbenzenthiol. F-PTEs were amorphous with good thermal properties including high glass transition temperature (T-g) and thermal stability, solubility, and hydrophobicity. F-PTEs were transformed into poly(aryl sulfone)s (F-PSs) by the oxidation reaction with hydrogen peroxide in acetic acid. Because of the sulfone group, the T(g)s of the F-PSs were 30-40 degrees C higher than those of the corresponding F-PTEs. F-PSs maintained solubility in polar aprotic solvents and exhibited hydrophobicity in spite of the content of polar sulfone groups due to the highly substituted fluorine atoms. These F-PTEs and F-PSs were a new class of high-performance polymers. (C) 2008 Wiley Periodicals, Inc.

DOI： 10.1002/app.27347

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Surface modification of thermotropic liquid crystalline aromatic polyester (LCP) films was examined by low-pressure plasma treatment to improve initial adhesion and long-term adhesive reliability between the LCP film and an epoxy bonding sheet for printed circuit boards. Plasma irradiation was carried out in various plasma gases with different plasma modes as reactive-ion-etching (RIE), direct-plasma (DP) with pressures ranging from 4.0 to 26.6 Pa. Although the initial adhesion of the DP-treated film increased, the long-term adhesive reliability estimated by pressure cooker test (PCT) decreased with decreasing the plasma gas pressure in every gas. The higher concentration of the generated polar groups such as phenolic hydroxyl group and carboxyl group enhanced the initial adhesion by the increase in the chemical interaction; however, it damaged the long-term adhesive reliability due to the acceleration of the penetration of water molecules into the interface. The large surface roughness was effective to enhance the initial adhesion and the long-term adhesive reliability. The RIE-treatment generated the polar groups and the larger surface roughness than the DP-treatment. The RIE-treatment in the O-2 atmosphere at the gas pressure of 13.3 Pa was the best plasma condition for both the initial adhesion and the long-term adhesive reliability. (C) 2007 Wiley Periodicals, Inc.

DOI： 10.1002/app.27537

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Selective preparation of poly(p-oxybenzoyl) (POB) crystals was examined from the viewpoint of a dimer effect on fractional polycondensation. Four different copolymerization systems were chosen as the combinations of p-acetoxybenzoic acid (p-ABA), m-acetoxybenzoic acid (m-ABA), and their dimers. The crystals obtained from the copolymerization of the dimer of p-ABA (p-ABAD) and m-ABA contained only 3.1 mol % of m-oxybenzoyl moiety even at high content of m-oxybenzoyl moiety in feed (chi(f)) of 40 mol %. p-Oxybenzoyl homo-oligomers were more rapidly formed from p-ABAD in the solution than from p-ABA, and they were crystallized to form the crystals with segregating co-oligomers. While co-oligomers containing more m-oxybenzoyl moiety were formed in the solution, afterward they were unable to be phase-separated because of higher miscibility. The further polycondensation proceeded in the precipitated crystal, and finally the POB crystal was selectively formed. Lower polymerization temperature and concentration enhanced the fractionability, and the POB crystals containing less than 1 mol % m-oxybenzoyl moiety were prepared at chi(f) of 30 mol %, 270 degrees C, and a concentration of 0.5%. The dimer effect on the fractional polycondensation was clearly observed. (C) 2008 Wiley Periodicals, Inc.

DOI： 10.1002/pola.22496

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Nonstoichiometric synthesis of poly(4,4 '-oxydiphenylene pyromelliteimide) was examined by using reaction-induced crystallization of oligomers during solution polymerization. Polymerizations of pyromellitic dianhydride (PMDA) and 4,4 '-oxydianiline (ODA) were carried out in Barrel Therm 400 at 330 degrees C at various molar ratios of PMDA and ODA in feed Q). Although high molecular weight polymer was usually prepared only under stoichiometric condition by a conventional solution polymerization, it was obtained as the crystals at chi of 0.5-2.0. The polymerization at chi of 0.77 afforded the highest polymer having M-w of 2.81 X 10(5), which was higher than that prepared by the solution polymerization. The oligomers were precipitated to form the crystals due to the low miscibility into the solvent. The precipitated oligomers were end-capped by excess monomers, but the end-capping groups were eliminated by transimidization reaction when they were registered into the crystals. The transimidization reaction also occurred in the crystals, leading to the increase in molecular weight. Since the nucleophilicity of amino end group was higher, the transimidization reaction proceeded more efficiently with eliminating ODA, and thereby the higher molecular weight polyimides were given in the range of chi < 1.0 than the range of chi > 1.0. The polymerization by the reaction-induced crystallization of oligomers was unsusceptible to the stoichiometry.

DOI： 10.1021/ma702030u

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BRILL ACADEMIC PUBLISHERS  

Surface modification of thermotropic liquid crystalline aromatic polyester (LCP) films was carried out by low-pressure plasma treatment to improve the initial adhesion as well as the long-term adhesion reliability, a measure of durability between the LCP films used as substrates for printed circuit boards. Plasma irradiation was carried out in various plasma gases with different plasma modes such as reactive-ion-etching, and direct-plasma (DP) with pressures ranging from 6.7 Pa to 26.6 Pa. The introduction of polar groups on the film surface such as phenolic hydroxyl groups and carboxyl groups enhanced the initial adhesion by increased chemical interaction. However, if the concentration of polar groups became too high, the long-term adhesion reliability estimated by the pressure cooker test was degraded due to the acceleration of the penetration of water molecules into the interface. A large surface roughness was also effective in preventing the decrease in the long-term adhesion reliability. However, too much increase in surface roughness decreases the long-term adhesion reliability. The DP-treatment in the O(2) atmosphere at a gas pressure of 6.7 Pa was found to be the best plasma condition for both the initial adhesion as well as the long-term adhesion reliability between the LCP films. (C) Koninklijke Brill NV, Leiden, 2008

DOI： 10.1163/156856108X331751

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS INC  

Fluorine-containing poly(aryl ether 1,3,4-ozadiazole)s were synthesized by the nucleophilic aromatic substitution reaction of 2,5-bis(2,3,4,5,6-pentafluorophenyl)-1,3,4-oxadiazole and various bisphenols in the presence of potassium carbonate. The polymerizations were carried out at 30 degrees C in 1-methyl-2-pyrrolidinone to avoid the gelation caused by a crosslinking reaction at para and ortho carbons to the 1,3,4-oxidiazole ring. The obtained polymers were all para-connected linear structures. The obtained fluorine-containing poly(aryl ether 1,3,4-ozadiazole)s showed excellent solubility and afforded tough, transparent films by the solution-casting method. They also exhibited a high glass transition temperature depending on the molecular structure, and the glass transition temperature could be controlled by the bisphenols in the range of 157-257 degrees C. They showed good thermal stability and excellent hydrophobicity due to the incorporation of the 2,3,5,6-tetrafluoro-1,4-phenylene moiety. (c) 2007 Wiley Periodicals, Inc.

DOI： 10.1002/pola.22041

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Influence of oligomer end-group on morphology of poly(4-oxybenzoyl) (POB) was examined by polymerizations of 4-acyloxybenzoic acids having different acyl groups. Polymerizations of 4-propionyloxybenzoic acid, 4-hexanoyloxybenzoic acid, 4-octanoyloxybenzoic acid and 4-decanoyloxybenzoic acid in liquid paraffin at 320 degrees C yielded needle-like or pillar-like POB crystals via crystallization of oligomers. On the other hand, the polymerization of 4-perfluorooctanoyloxybenzoic acid (FOBA) afforded microspheres having needle-like crystals on the surfaces. At an initial stage in the polymerization, microspheres having smooth surface were formed via liquid-liquid phase separation of oligomers prepared from FOBA owing to the low miscibility of perfluorooctanoyl end-group. Thereby the phase-separation behaviour of oligomers changed from liquid-liquid phase separation to crystallization at a middle stage in the polymerization and then needle-like crystals were formed on the surface of the microspheres. Chemical structure of the oligomer end-group affected significantly the phase-separation behaviour of oligomers and ultimately the morphology of POB. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2007.04.025

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Morphology control of various aromatic polyimides representative as poly(4,4'-oxydiphenylene pyromelliteimide) was examined by using the phase separation during solution polymerization. Polymerizations of aromatic dianhydrides and aromatic diamines to the polyimides were carried out in poor solvents at 240-330 degrees C for 6 h with no stirring. Polymerization concentrations were from 0.25% to 3.0%. The polyimides were obtained as yellow precipitates. Two categorized morphologies were created, which were particles and crystals exhibiting lath-like and plate-like habits. These morphologies of polyimides could be selectively controlled by the polymerization conditions. The higher concentrations, less miscible solvents and lower temperatures were preferable to yield the particles via liquid-liquid phase separation. On the contrary, the lower concentration, miscible solvents and higher temperature were desirable to yield the crystals. The polyimide precipitates showed high crystallinity and possessed excellent thermal stability at which the 10 wt% loss temperatures in N-2 were in the range of 590-694 degrees C. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2006.11.061

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Morphologies of poly(p-phenylene pyromelliteimide) (PPPI) were investigated by using phase separation during polymerization of pyromellitic dianhydride (PMDA) and p-phenylene diamine (PPDA). Polymerizations were carried out at 330 degrees C for 6 h. PPDA was added to the solution of PMDA in an aromatic solvent at various temperatures after PMDA was entirely dissolved. The morphology of the precipitates was drastically changed with the temperature of PPDA addition (Tad). When Tad was 240 degrees C, the fine particles were formed through the formation of droplets via liquid-liquid phase separation. On the contrary, when Tad was higher than 280 degrees C, the mixture of lozenge-shaped crystals and starlike aggregates of needlelike crystals were formed by the crystallization of oligomers. Tad influenced the degree of imidization of oligomers, resulting in the variation in the morphology of PPPI. Crystal structure and molecular chain orientation of the lozenge-shaped crystals were also investigated by high-resolution transmission electron microscope.

DOI： 10.1021/ma062032y

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

"How do chain molecules spontaneously entangle from completely disentangled polymer melt?" remains the most interesting unsolved problem. In order to solve this problem, we used the concept that the melt of "nascent" polymer crystallized during polymerization just after melting does not include any entanglements. We succeeded in detecting the increase of entanglement density v(e) with the increase of annealing time At above the equilibrium melting temperature before isothermal crystallization. The increase of v(e) was detected by observing the decrease of nucleation rate I from the melt of nascent polymer with different Delta ts. I is a very sensitive detector of entanglements because the nucleation is a rearrangement process of chains to the crystalline lattice through the disentanglement. Therefore, I is significantly suppressed with the increase of v(e). We found a two-step decrease of I with an increase of Delta t for the first time. This should correspond to a two-step increase of v(e) with an increase of Delta t. This indicates that simple entanglements such as twist or knot with lower order (one time knot) were formed within short time and then the complicated ones such as knot with higher order (two or three times knots) or loops (entanglements by loop conformation) were formed. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2006.07.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC FIBER SCIENCE TECHNOLOGY  

Various amide-containing aryl fluorides were synthesized from 2,3,4,5,6-pentafluorobenzoic acid, and novel fifteen AA-BB type and three AB type fluorine-containing poly(aryl ether amide)s (F-PEA) were obtained by nucleophilic aromatic substitution reaction. The synthesized aryl fluorides possessed several reactive carbons for the nucleophilic attack and cross-linking reaction occurred at 100 degrees C. Polymerizations were carried out at 80 degrees C to avoid cross-linking and stopped just before gelation occurred. They had all para connected linear structures. The obtained F-PEAs showed excellent solubility and afforded tough transparent films by casting method. They also exhibited high Tg in the range of 179-273 degrees C depending on the molecular structure. They showed good thermal stability, and even though F-PEAs contained amide linkage into the repeating unit of polymer molecule, they exhibited excellent hydrophobicity due to the incorporation of 2,3,5,6-tetrafluoro-1,4-phenylene moiety.

DOI： 10.2115/fiber.62.155

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC FIBER SCIENCE TECHNOLOGY  

Fabrication of poly(p-oxycinnamoyl) (POC) nano-scale particles was examined by using self-seeding polymerization of (E)-4-acetoxycinnamic acid in liquid paraffin. The diameter of the POC spheres was very susceptible to the polymerization temperature and the temperature drop was very efficient to control the nucleation process by the adjustment of the degree of super saturation leading to the decrease in the diameter. The average diameter of the spheres prepared at 320 degrees C was 3.6 mu m, whereas, the temperature drop from 320 degrees C to 250 degrees C just before the nucleation afforded the POC microspheres having average diameter of 2.2 mu m. In order to prepare the nano-scale particles, only the self-seeding polymerization was not sufficient and the control of the growth process was additionally required. The POC particles having 600 nm of the average diameter were obtained by not only the temperature change from 320 degrees C to 250 degrees C and then 320 degrees C but also the addition of 4-octadecyloxybiphenyl as a coalescence inhibitor. The average diameter was in nano-scale, but the diameter distribution became broader with bimodality.

DOI： 10.2115/fiber.62.167

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Isothermal crystallization of three-dimensional (3D) spherulites from the bulky melt under low shear rate flow was Studied based on new in situ observation along a direction perpendicular to the flow velocity a adient plane (XZ plane) by means Of optical microscope, where X- and Z-axes are perpendicular and parallel to the flow direction, respectively. Spherulites are rotating. A novel "spiral pattern" was found oil the surface of the rotating "half-spherulite" near the surface of the melt for the first time. The half-spherulite is named "spiralite" which enabled us to have a visible image of the rotation of Spherulite. Hence, we could detect the growth rate around the Z-axis V(Z) and that around the X-axis V(X) by using the spiral pattern. We could experimentally obtain V(Z) > V(X) in this study. From kinetic viewpoint. this fact indicates that free energy for formation of a critical nucleus around file Z-axis is smaller than that around the X-axis. From this, it is concluded that the 1 oriented melt" is formed around the 7 axis. We proved it theoretically by showing that micro shear rate (Z) on the interface around the Z-axis significantly increases and chains will be elongated even when macro is low (y < 10 s(-1)). With increase of y(Z), the chain elongation will overcome the entropic relaxation, that results in formation of the "oriented melt". Crystallization mechanism under low shear flow is proposed that file growth rate of spherulite or shish is accelerated around interface, due to formation of the "oriented melt". Finally, we proposed a possible relationship between Inch Structure and crystallization under anisotropic and isotropic external fields.

DOI： 10.1021/ma050825z

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Language：English   Publisher：NATURE PUBLISHING GROUP  

Morphology control methods of aromatic polymers in concert with polymerization reaction are described in this review. Many attractive methods have been developed including reaction-induced phase separation of oligomers, epitaxial polymerization, shear-induced chain orientation during gelation, template-based polymerization, suspension polycondensation, solid-state polycondensation and liquid-liquid interfacial precipitation and so on. Among them, the reaction-induced phase separation of oligomers, in which there are two modes of crystallization and liquid-liquid phase separation, possess practically high potentiality to create novel polymer materials since it can control not only the morphology but also the molecular chain orientation. Ultimate goal is the embodiment of the nature system in a flask, that is, the control of the materials from primary structures to super structures. The morphology control methods by using polymerization reaction afford the valuable methodology for the three-dimensional structure architecture.

DOI： 10.1295/polymj.PJ2006083

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

In part I of this series of paper, we have solved the formation mechanism of shish from the oriented melt based on the kinetic observation. In this work, we have shown for the first time the molecular mechanism of the growth of shish by kinetic study. We found that there are two different type of the growth of shish against the flow direction. The growth rate along the flow direction (U) is proportional to DeltaT, where DeltaT is the degree of supercooling. This indicates that U is mainly controlled by the rearrangement process of the chain near the end surface of the shish. On the other hand, the growth rate perpendicular to the flow direction (V) obeyed a well-known equation Vproportional to exp(-B/DeltaT), where B is a constant proportional to the free energy necessary for forming a critical secondary nucleus DeltaG*. This indicates that V is mainly controlled by the secondary nucleation process on the side surface of shish. Moreover, we also found that there is a critical shear rate gamma (over dot)* for the growth of shish. Below gamma (over dot)*, U and V approached to zero and the growth rate of spherulite, respectively. From this experimental fact, we proposed that the chain conformation near the interface between the melt and shish, i.e. near the end and side surface of shish is elongated and oriented by the shear flow above gamma (over dot)*. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2004.12.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JOHN WILEY & SONS LTD  

Electrical conductivity and electromagnetic interference (EMI) shielding effectiveness at microwave (200-2000 MHz) and X-band (8-12 GHz) frequency range of polyaniline (PAni) composites were studied. It has been observed that EMI shielding of conductive polyaniline (PAni)-ethylene vinyl acetate composites increases with the increase in the loading levels of the conductive polymer doped with dodecylbenzene sulfonic acid. The result indicates that the composites having higher PAni loading (> 23%) can be used for EMI shielding materials and those with lower PAni loading can be used for the dissipation of electrostatic charge. (C) 2004 Society of Chemical Industry.

DOI： 10.1002/pi.1660

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

We have solved the molecular mechanism of the formation of shish of isotactic-polypropylene (iPP) and polyethylene (PE) from the sheared melt based on kinetic study by means of polarizing optical microscope. We found that the rate determining process for the formation of shish is a nucleation process in the most range of degree of supercooling (DeltaT) except for large DeltaT of PE. We have shown a direct evidence of the formation of bundle nucleus from the oriented melt, which is consisted of elongated chains caused by artificial pins. For polymers, a universal mechanism of nucleation from the isotropic or oriented melt was proposed. We also found that there is a critical shear rate for the formation of shish. This experimental fact indicates that the shish will be formed when the elongation of chains will overcome the conformational relaxation of chains and chain conformation within the oriented melt is kept liquid crystal like one. (C) 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2004.12.009

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Fabrication of poly(p-oxybenzoyl) (POB) nanowhiskers was examined by using reaction-induced crystallization of oligomers during the polymerization of p-acetoxybenzoic acid in liquid paraffin. Width of the POB whiskers was susceptible to polymerization temperature and it was efficiently controlled by a change in temperature during the polymerization. Increase in polymerization temperature just after nucleation (Han) reduced the degree of super saturation of oligomers (or) resulting in the depression of the width increase by the crystallization of oligomers on side surface of the whiskers. Temperature drop just before nucleation (Cbn) enhanced the value of a resulting in the generation of much more nuclei having the smaller width. On the basis of these results, the combination of these two methods Han and Cbn afforded the whiskers having the smallest width, and the POB nanowhiskers were prepared of which the width and the length were 190nm and 18.6 mu m, respectively.

DOI： 10.1295/polymj.37.906

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER-VERLAG BERLIN  

Direct evidence of nucleation during the induction period of nucleation from the melt is obtained for the first time by means of small angle X-ray scattering (SAXS). This confirmed that the induction period of crystallization from the melt corresponds to the process of nucleation, not to that of spinodal decomposition. This success is due to a significant increase in the scattering intensity (I-x) from the nuclei (10(4) times as large as is normal), which was achieved by adding a nucleating agent (NA) to a "model polymer" of polyethylene (PE). Ix increased soon after quenching to the crystallization temperature (T-c) and saturated after the induction time (tau(i)). Lamellae start stacking later than the tau(i).
Power laws of the molecular weight (M-n) dependence of the primary nucleation rate (I) and the growth rate (V) of PE, i.e., I or V proportional to M-n(-H) where H is a constant, were found for both morphologies of folded chain crystals (FCCs) and extended chain crystals (ECCs). As the power law was also confirmed on isotactic polypropylene (iPP), universality of the power law is suggested. it is to be noted that the power H increases significantly with increase of the degree of order of the crystal structure. The power law confirms that the topological nature of polymer chains, such as chain sliding diffusion and the chain entanglement within the interface between the nucleus and the melt or those within a nucleus, adopts a most important role in the nucleation and growth of polymers. This is theoretically explained by improving the "chain sliding diffusion theory" proposed by Hikosaka.
Entanglement dependence of the nucleation rate I is qualitatively obtained for the first time by changing the number density of entanglement (nu(e)) within the melt. An experimental formula of I as a function of nu(e) was obtained on PE, I(nu(e)) proportional to exp(-gamma nu(e)) where gamma is a constant.

DOI： 10.1007/12_010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A new method to determine the correct Gibbs-Thomson plot and equilibrium melting temperature (T-m(0)) of polymers was proposed. The Gibbs-Thomson plot method is reliable, because the Gibbs-Thomson equation is directly derived from thermodynamical relations. In this method, the heating rate dependence of melting temperature (T.) was omitted by applying the theory of the "melting kinetics", and the effect of lamellar thickening on T. was also omitted by observing thick lamellae. A differential scanning calorimeter (DSC) was used for observation of T. as a conventional method. Transmission electron microscope (TEM) was used to observe a distribution of lamellar thickness (l). It was shown theoretically that peak temperature of melting endotherm (T.(DSC)) corresponded to averaged reciprocal l (<l(-1)>) for the case of sharp distributions of T-m and l(-1). The Gibbs-Thomson plot, T-m (DSC) vs <l(-1)>, was carried out. A reliable Gibbs-Thomson plot and T-m(0) = 186.2 degreesC were obtained for a fraction of isotactic polypropylene (iPP) with high tacticity ([mmmm] = 99.6%, M-n = 64 x 10(3) and MwMn = 2.4). It was shown that DSC double melting endotherm corresponded to the number-distribution of l(-1), when lamellar thickening did not occur.

DOI： 10.1021/ma021206i

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

In part 1 of this series, we proposed a new method to determine the correct equilibrium melting temperature (T-m(0)). Effects of the "melting kinetics" and lamellar thickening were omitted from T-m. The correct T-m(0) of isotactic polypropylene (iPP) ([mmmm] = 99.6%, M-n = 64 x 10(3), and M-w/M-n = 2.4) was observed to be 186.1 degreesC. In this paper, the rigorous Gibbs-Thomson plot was obtained by using the direct correspondence between maximum melting temperature (T-m,T-max) and maximum lamellar thickness (l(max))- T-m,T-max and l(max) were observed by means of optical microscope and transmission electron microscope (TEM), respectively. The validity of the Gibbs-Thomson plot obtained by means of a differential scanning calorimeter (DSC) (part 1 of this series) was confirmed by comparing it with the rigorous Gibbs-Thomson plot in this paper. The Hoffman-Weeks plot is widely used as one of the methods to obtain T-m(0). It was shown that the Hoffman-Weeks plot is correct only when l proportional to 1/DeltaT where DeltaT is the degree of supercooling, is satisfied. However, in the case of iPP, the condition is not satisfied, and so the result obtained by the Gibbs-Thomson plot is not equivalent to that obtained by the Hoffman-Weeks plot. The existence of alpha2' phase was confirmed again by breakings in slopes of l and T-m against T-c at 159 degreesC. Furthermore, the broad bimodal distribution of l was caused by the difference between the lamellar thickening growth rate of isolated mother lamellae and the lamellae thickening rate of stacked daughter lamellae.

DOI： 10.1021/ma021207a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MARCEL DEKKER INC  

Direct evidence that nuclei are formed during the induction period of crystallization is obtained for the first time by means of small-angle X-ray scattering (SAXS). Polyethylene (PE) was used as a model crystalline polymer. The nucleating agent was mixed with PE in order to increase the scattering intensity I-x from nuclei as large as 10(4) times bigger than usual. I-x increased soon after quenching to the crystallization temperature from the melt and saturated after some time. A new theory is proposed to estimate the size of the nuclei N, the number density distribution of nuclei with N at time t, f(t,N), and the induction time tau(i), by analyzing the SAXS scattering intensity. The volume-averaged size of the nuclei nearly the same as that of critical nuclei and does not change so much with time during the induction period. Lamellae start stacking much later than nuclei start forming.

DOI： 10.1081/MB-120021610

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MARCEL DEKKER INC  

Molecular weight (M) dependence of the equilibrium melting temperature (T-m(o)) of isotactic polypropylene (iPP) with high tacticity ([mmmm] = 99.6%) was studied. Four fractionated iPPs with M-n = 23 x 10(3), 64 x 10(3), 94 x 10(3), and 263 x 10(3) were used. T-m(o) was obtained by using an improved method based on the Gibbs-Thomson plot proposed in previous papers. The effect of "melting kinetics" on melting temperature (T-m) was eliminated by observing isothermal melting of spherulites. The effect of lamellar thickening on Tm during T, measurement at high temperature was also eliminated by observing thick lamellae formed at high crystallization temperatures (T-c = 148 similar to 166 degreesC). With increase of M, T-m(o) increased significantly. The empirical equation, T-m(o) = 119.5 + 23.6 x log M - 2.0 x (log M)(2) (degreesC), was obtained. The molecular weight dependence of the alpha2-alpha2' transition was observed. The transition temperature (Talpha2-alpha2') also increased with increase of M. The DeltaT dependence of lamellar thickness was concluded to be controlled by that of lamellar thickening.

DOI： 10.1081/MB-120021603

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MARCEL DEKKER INC  

Effect of the shear flow ((gamma)over dot = 0.5 similar to 5 s(-1)) on the nucleation and on the morphology of polyethylene (PE) during crystallization from the melt was studied by means of polarizing optical microscopy and small angle X-ray scattering. In order to analyze the results by the nucleation theory, we observed the effect of shear flow on the equilibrium melting temperature (T-m(0)). The T-m(0) under shear flow and that under quiescent state are almost the same, T-m(0) = 140.2 similar to 140.3degreesC. Therefore, the shear flow does not affect the T-m(0). The "heterogeneous" primary nucleation rate (1) and the induction onset time of nucleation (tau(onset)) of the isolated crystals under shear flow are also almost the same as those under quiescent state. The heterogeneous primary nucleation means that isolated nuclei are sporadically generating from the melt with the aid of heterogeneities such as nucleating agents. After the generation of primary nuclei, the "shish" were generated independent of the primary nucleation. We found that the shish were formed by the chain elongation caused by the velocity difference between polymer chains and dust particles, etc. After that, we observed that the "kebabs" were formed on the shish. It was found that the nucleation from the melt after melting of the "shish-kebabs" (at melt annealing temperature T-max = 160degreesC for 5 min) was accelerated compared with the ordinary melt crystallization after melting of folded chain crystals. This indicates that the "solid memory effect" of the former solid is significant. This is because of the low entanglement density within the melt of shish kebabs.

DOI： 10.1081/MB-120021578

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

An experimental formula of the nucleation rate I of polyethylene as a function of number density of entanglement v, within the melt was obtained as I(nu(e)) proportional to exp(-gammanu(e)), where gamma is a constant. In order to obtain a functional form of I(nu(e)), I is determined by changing v, within the melt. The nu(e) within the melt can be changed when crystals with different lamellar thickness I are melted. It is shown that the nu(e) within the melt just after melting is related to I before melting. The v. of folded chain crystals (FCCs) is large, while that of extended chain single crystals (ECSCs) is very small. Therefore, strictly speaking, the experimental formula is a kind of 'semi-experimental' one. Because it is obtained by combining an experimental formula of I as a function of 1 before melting I(l) and a formula between I and v, based on the most probable model. It was found that the v, dependence of I is mainly controlled by the topological diffusion process within the interface between the melt and a nucleus and/or within the nucleus not by the forming process of a critical nucleus. The slope of the plots of log I against DeltaT(-2) was constant, irrespective of morphologies, FCCs and ECSCs, where AT is the degree of supercooling. From this fact, it was concluded that the fold type nucleus are formed from the melt of ECSCs as well as from the melt of FCCs. In our previous study, we found that I decreases exponentially with increase of annealing time At at a temperature above the melting temperature. From these results, we proposed a 'two-stage melt relaxation', i.e. fast conformational and slow topological relaxations. When the ECSCs are melted, extended chains within ECSCs are rapidly changed to random coiled chain conformation and then chains gradually entangle each other. We also proposed a formula, nu(e)(Deltat) proportional to -In{const. + A exp(-Deltat/tau(m))}, where A is a constant and tau(m) is the 'melt relaxation' time. (C) 2002 Published by Elsevier Science Ltd.

DOI： 10.1016/S0032-3861(02)00592-X

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

molecular weight (M.) dependence of the primary nucleation rate (I) of folded chain single crystals (FCSCs) of polyethylene (PE) was studied. A power law for the nucleation rate, I proportional to M-n (-2.4), was found. The FCSCs were formed by isothermal crystallization from the melt into an ordered phase (=orthorhombic phase). A new experimental method was established to obtain reliable I, which has been difficult in the case of heterogeneous nucleation for long years. The degree of supercooling (DeltaT) dependence of I fits well with the theoretical I given by classical nucleation theory, I = I-0 exp(-DeltaG*/kT) proportional to D exp(-C/DeltaT(2)), where I-0 is proportional to the topological diffusion coefficient of polymer chains (D), DeltaG* is the free energy for forming a critical nucleus, k is the Boltzmann constant, T is temperature, and C is a constant. It is found that DeltaG* (-C) does not depend on M., while I0 decreases with increase of M., from which it is concluded that formation of a critical nucleus is not controlled by M., while only topological diffusion of polymers is controlled by M-n, i.e., I proportional to D(M-n). Similar power laws of PE were already found by the present authors on I of extended chain single crystals (ECSCs), i.e., I proportional to M-n(-10), and on the lateral growth rates (V) of ECSCs and FCSCs, V proportional to M-n(-0.7) and V proportional to M-n(-1.0), respectively. ECSCs were formed by isothermal crystallization from the melt into a disordered phase (=hexagonal phase). Therefore, it is concluded that a common power law, I, V proportional to D(M-n) proportional to Mn-H of PE is confirmed, irrespective of nucleation or growth and irrespective of crystalline phases, ordered or disordered phases. It is to be noted that the power H depends on the degree of order of the crystalline phase, from which it is concluded that both nucleation and growth are controlled by the "topological" diffusion of polymer chains within interface between a nucleus (or crystal) and the melt and/or within the nucleus. The "topological" diffusion is related to chain sliding diffusion and disentanglements.

DOI： 10.1021/ma0105901

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

A second-order phase transition of alpha2 form isotactic polypropylene (iPP) is found at high annealing temperature (T-a = 159.3 degreesC) by means of X-ray diffraction method. Although the lattice shape and the space group keep the same as those of the alpha2 form, i.e. monoclinic and P2(1)/c, with increase of T-a, it has been revealed that there are discontinuous increases in the slopes of the lattice constants a and b against T-a plots, while the c and the beta keep almost constant. As a result, the slope of the unit cell volume V versus T-a plot also shows a discontinuous increase at T-a = 159.3 degreesC, indicatin- the occurrence of the second-order phase transition. In order to distinguish the two phases, the phase above the transition temperature is named alpha2' phase and the transition temperature is denoted Talpha2-alpha2'. These facts suggested that the alpha2' form is a mobile phase where the molecular chains would become loosely packed and mobile, promoting the better chain sliding diffusion. A fast lamellar thickening process has been confirmed in the higher temperature region than Talpha2-alpha2', which was reported in the precedent paper. General significance is proposed that mobile phases possibly exist at high temperature, close to the melting temperature and accelerate lamellar thickening, which improves physical properties of polymers. (C) 2001 Published by Elsevier Science Ltd.

DOI： 10.1016/S0032-3861(01)00667-X

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC POLYMER SCIENCE JAPAN  

DOI： 10.1295/polymj.33.906

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

DOI： 10.1295/polymj.32.87

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

To characterize the local conformations of ionenes, persistence lengths (P-1) were measured for 4,4-, and 6,6-ionenes (m,m-ionene) and 1,1-oxyethyleneionene (1,1-OEI) in methanol by small-angle X-ray scattering. It was found that P-1's of all the ionenes are almost identical (1.4 +/- 0.2 nm).

DOI： 10.1021/la981120b

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Potentiometric titration of aliphatic alpha,omega-diamines such as 1,3-, 1,3-, and 1,6-diamines was carried out in aqueous solutions with and without added salt to study the effect of electrostatic interactions on the chain conformations. The ratios of first to second association constants of proton K-1/K-2 were larger than 4 indicating the effects of electrostatic interactions on the second association constant in a similar manner as alpha,omega-diacids. These data were analyzed by the theories of Bjerrum and Kirkwood-Westheimer, and the resulting charge distances were compared with the end-to-end distances of various chain models.

DOI： 10.1295/polymj.31.1237

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Measurement of C-13 spin-lattice relaxation times, T-1, and nuclear Overhauser effects, NOE, was made as a function of temperature at two magnetic fields for poly(t-butyl crotonate), PTBC, and poly(t-butyl methacrylate), PTBM, in toluene-d(8) to study the effects of beta-substitution on local chain motions. For main chain carbons of MBC and PTBM, experimental T-1 and NOE data were well reproduced by the Dcjean-Laupretre-Monneric (DLM) model in the entire temperature range. The model parameters thus obtained differed between PTBC and PTBM. For methyl carbons in the t-butyl ester group, the experimental data were analyzed by the models combining the DLM model and multiple internal rotations. The model parameters were almost the same for the two polymers. These results indicate that beta-substitution affects the local motion of main chains as well as chain stiffness, but does not significantly affect the local motion of methyl carbons at the ends of side-chains. The correlation between the local dynamics of various polymer chains and chain stiffness is discussed.

DOI： 10.1295/polymj.31.542

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Measurements of C-13 spin-lattice relaxation times, T-1, and nuclear Overhauser effects, NOE, were carried out as a function of temperature at two magnetic fields for iso-poly(2-vinylpyridine) (iso-P2VP) in I,4-dioxane-d(8) and iso-poly(2-vinylpyridinium chloride) (iso-P2VPCl), in D2O to investigate the effects of electrostatic interactions on local chain dynamics. For main chain carbons of both polymers, the experimental T-1 and NOE data are in good agreement with the Dejean-Laupretre-Monnerie (DLM) model in the entire temperature range. It was found that the local conformational transitions of main chain and the libration are more restricted for iso-P2VPCl than iso-P2VP. For pyridyl ring carbons, the experimental data were reproduced by the models combining the DLM model and restricted ring rotations. The angular amplitude alpha of ring rotation of iso-P2VPCl is smaller than that of iso-P2VP. These results imply that both local motions of main chain and side chain are affected by the electrostatic interactions.

DOI： 10.1295/polymj.31.614

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER CHEMICAL SOC  

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Event date： 2021.11.18 - 2021.11.19

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Language：Japanese   Presentation type：Poster presentation  

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Event date： 2021.11.18 - 2021.11.19

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.11.17

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Event date： 2021.11.4 - 2021.11.5

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2021.11.4 - 2021.11.5

Language：Japanese  

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Event date： 2021.9.6 - 2021.9.8

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2021.9.6 - 2021.9.8

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2020.11.5 - 2020.11.6

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.11.5 - 2020.11.6

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.11.5 - 2020.11.6

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.11.5 - 2020.11.6

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.6.10 - 2020.6.12

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2020.6.10 - 2020.6.12

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2020.5.27 - 2020.5.29

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.5.27 - 2020.5.29

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.3.22 - 2020.3.25

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2019.6.5 - 2019.6.7

Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English  

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Language：English   Presentation type：Oral presentation (general)  

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Language：English  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English  

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Language：English  

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Language：English  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English  

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Language：English  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English  

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Language：English  

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Language：English  

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Language：Japanese   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Poster presentation  

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