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Volume 34, Issue 12
Displaying 1-9 of 9 articles from this issue
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Tsuyoshi KIYOTSUKURI, Yasumichi MIURA, Shoichi KAWAMORI1977 Volume 34 Issue 12 Pages 821-827
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSNylon 610-6T and nylon 66-6T copolymers containing 40 mol% of 6T and 60 mol% of the other component were synthesized by interfacial copolycondensation in 9 different solvents. DTA analysis suggested that the copolymers ranged from block to random type; the sequence length of the copolymers is dependent on the solvent used. Films were prepared by casting from dichloroacetic acid solutions of the block type copolymers obtained in carbon tetrachloride or chloroform, as well as the random copolymers and polymer blends of the same composition as the block copolymers. It is supposed from DTA and X-ray analyses for the film samples that the copolymers obtained in carbon tetrachloride have longer sequence lengths than the copolymers prepared in chloroform, and that nylon 66-6T copolymers are isomorphous. Dynamic viscoelasticity measured for the film samples revealed that the nylon 66-6T copolymer prepared in carbon tetrachloride has relatively high loss modulus maximum temperature and dynamic modulus. This result suggests the importance of sequence length and isomorphism on the viscoelastic properties of nylon copolymers.View full abstractDownload PDF (1121K) -
Yoshihiro BABA, Akihiro KAGEMOTO, Hirotomi TANAKA, Yuichi MATSUMURA1977 Volume 34 Issue 12 Pages 829-832
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe heats of helix-coil transition (ΔHd) of rat skin collagen with different fractions of subunit compositions (α and β) obtained by the different extraction methods were measured using a modified differential scanning calorimeter. ΔHd of the collagen having α/β value of 0.45 (acid-soluble collagen, C-C) is 2 to 2.5 times as large as that having the value of 3.6 (salt-soluble collagen, S-C). In solutions of pH range from 3 to 5, ΔHd (12 J/g) of S-C increases slightly with increasing pH, but ΔHd of C-C is nearly constant, about 30 J/g, independent of pH. The difference in ΔHd between S-C and C-C may be due to different helical contents of the collagens.View full abstractDownload PDF (585K) -
Takashi KAMON1977 Volume 34 Issue 12 Pages 833-841
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSRelation between the molecular structure and dynamic mechanical properties has been studied for various epoxy resins cured with typical curing agents such as diaminodiphenylmethane and methylhexahydrophthalic anhydride. The modulus in rubber region and the front factor in the equation of state for rubber elasticity increased with the increase of crosslinking density, phenyl group contents, and especially structural symmetry in the crosslinking resins. The glass transition temperature (Tg) increased with the increase of the crosslinking density, polarity, and especially phenyl group contents of the cured resins. The relation between the modulus in glassy region and molecular structure of epoxy resin was somewhat obscure, but the glassy modulus might be related to Tg of the cured resins. Bending stress and maximum strain of the resins were also discussed.View full abstractDownload PDF (1458K) -
Masao HOSONO, Shinji SUGII, Waichiro TSUJI1977 Volume 34 Issue 12 Pages 843-850
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolyelectrolyte complexes were prepared from carboxymethylated poly (vinyl alcohol) (I) and aminoacetalized poly (vinyl alcohol) (II) under various conditions and their structural changes upon heating were investigated by infrared spectroscopy. Films prepared by casting the sodium hydroxide or hydrochloric acid aqueous solutions containing I and II were simple physical mixtures, but washing of the films with methanol yielded polyelectrolyte complexes having ionic bonds. Heating of the complexes above 120°C gave rise to transformation of the ionic bonds to amide linkages (-NH3+: -OOC-→-NH-CO-+H2O). However, when the films made from sodium hydroxide solutions were heated without washing with methanol, no amide but hydrogen bonding due to NH2 groups was observed. In contrast, amide formation took place on heating the films which were prepared from hydrochloric acid solutions but not subjected to washing with methanol. This may be due to disappearance of hydrochloric acid through heating, resulting in formation of ionic bonds.View full abstractDownload PDF (1398K) -
Satoshi MORIMOTO1977 Volume 34 Issue 12 Pages 851-855
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSHeats of neutralization (ΔHn) of poly (caboxylic acid) s, e. g., polyacrylic (I) and polymethacrylic (II) acids, and related monomeric acids, e. g., propionic (III) and iso-butyric (IV) acids, with sodium hydroxide have been measured directly in the vicinity of neutral point, at 21°C and both 0.1 M concentrations. The following results were obtained and discussed; (1) characteristic ΔHn behavior of II acid in acidic region, (2) maximum ΔHn values of polymeric acids in slightly alkaline region and (3) considerably large difference of ΔHn value between polymeric and the monomeric acids. The maximum ΔHn values observed for these acids were III: -13.7, I: -5.8, IV: -13.8 and II: 10.1 kcal·mol-1. The apparent ionization enthalpy and entropy of polymeric acids increase remarkably than those of the related monomeric acids and the increase for I is larger than that for II.View full abstractDownload PDF (852K) -
Iwao TAKASE, Tadashi TANIGUCHI, Hiroshi AIDA1977 Volume 34 Issue 12 Pages 857-865
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe radical homopolymerization and copolymerization behaviors of eight N-substituted isomaleimides (RIMI) have been studied. The polymerizations of RIMI proceed slowly to yield low melecular weight polymers, and influence of N-substituents on over-all polymerization rate was observed. The copolymerizations of RIMI (M2) with styrene (M1), methyl acrylate (M1), and vinyl acetate (M1) were carried out at 70°C in dioxane. The relative reactivities (1/r1) of RIMI toward a polystyryl and a poly-(methyl acrylate) radical were correlated with the polar substituent constants (σ*) of alkyl groups in RIMI in Taft's equation; log (1/r1) =ρ*σ*+δEs, being independent of the steric substituent (δ=0). The ρ* values obtained for styrene-RIMI and methyl acrylate-RIMI systems were 0.9 and 0.4, respectively. The Q and e-values for RIMI obtained from its copolymerization with styrene were also correlated with Taft's σ* constants. The Q and e-values for RIMI increase with increasing σ* values. In the copolymerizations of RIMI with vinyl acetate, alternating copolymers of low molecular weights were obtained.View full abstractDownload PDF (1409K) -
Moriyuki SATO, Takao UCHIDA, Masaaki YOKOYAMA1977 Volume 34 Issue 12 Pages 867-870
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPhosphorus-containing poly (Schiff base) s of the following general formula were prepared by melt
polycondensation of bis (3-aminophenyl) alkylphosphine oxide with aromatic diketones. The polymers obtained were insoluble in common solvents, and slightly soluble in conc. H2SO4. Thermal analyses showed that these polymers degradate abruptly in air above 500°C but have high thermal stability in nitrogen. Apparent activation energies for thermal decomposition of the polymers in air were 41-68 kcal/mol. Most of the absorption bands observed in the IR spectra of the polymers vanished when the polymer was heated at 700°C. The polymers were self-extinguished as soon as the flame was removed.View full abstractDownload PDF (589K) -
Kosuke TOMITA1977 Volume 34 Issue 12 Pages 871-873
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSCatalytic effect of zinc acetate on the pyrolysis of p, p′-disubstituted ethylene dibenzoate (EDB) was investigated in order to elucidate the characteristic of the catalytic effect of metal compound on the thermal degradation of poly (ethylene terephthalate). p, p′-Disubstituted EDB was pyrolyzed at 330°C and the rate constants were evaluated from the quantity of unreacted EDB. It was found that the Hammett equation can fairly be applied for the reaction to give a positive ρ value. In the presence of zinc acetate, similar results were obtained, but ρ value decreased. This phenomenon suggests that the effect of p, p′-substituents is reduced by the addition of a metal compound which acts as Lewis acid and provides a catalytic effect similar to that of an electron withdrawing substituent.View full abstractDownload PDF (466K) -
Takashi HANDA, Shuji YOSHIZAWA, Masaaki SUZUKI1977 Volume 34 Issue 12 Pages 875-876
Published: December 25, 1977
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolymer-wood interaction in polystyrene (PSt) -wood polymer composite (WPC) prepared by injecting PSt (Mn: 1.8×103, 6.0×103, 1.1×104, 1.1×105) into wood was pursued by storage (ET′) and loss modulus (ET″). Three peaks of ET″ were observed at 100°C, 125°C, and 150-220°C, besides one at 230°C which is originally found in wood. Splitting of ET″ peak (110-130°C) into two at 100°C and 125°C and ET″ terrace (150-220°C) formation were recognized with the decrease of Mn. The peak at 125°C did not depend on Mn. Low Mn (1.8×103) WPC showed a small ET″ terrace. The specificity of Mn in ET″ patterns seemed to depend on the difference in mode of polymer adsorption to cellular surface.View full abstractDownload PDF (356K)
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