Polymer Journal

Ishida, Shin-ichiro; Murase, Masaaki; Kaneko, Katsumasa

doi: 10.1295/polymj.11.835pmid: N/A

The formation mechanisms of phenolic resins were studied by computer simulation. As an example, the process for the polymerization of o-methylolphenol is as follows: (1) the number of methylol groups and nuclear hydrogens of o- and p-position are stored, (2) a methylol group is selected, (3) a functional group of another molecule is selected to react with the methylol group previously selected, and (4) a molecule freshly formed is fed back into the computer. In this simulation, the reactivity of the functional group is represented by the probability that the group is selected. This procedure is iterated until the extent of reaction reaches to the same value as that of the practical reaction calculated from GPC chromatogram. Discussion about the reactivity of each functional group was made by comparsion of the molecular weight distribution of the hypothetical product in the computer with that of the actual one. From these results, it is known that the formation of dimethylene ether linkage is negligibly small compared to that of the methylene linkage and a methylol group is more reactive with a nuclear hydrogen in the disubstituted phenol than in the monosubstituted phenol.

Okada, Tadashi

doi: 10.1295/polymj.11.843pmid: N/A

Carbon-13 spin-lattice relaxation times and line-widths have been measured for solutions of o-, m-, and p-methyl derivatives of polystyrene at temperatures ranging between 30 and 60°C. Spin-lattice relaxation times of these polymers are intimately related with molecular motions, namely, the segmental motion and two internal motions of the phenyl and methyl groups. With respect to the internal rotation of the phenyl group, a transition change was observed in the vicinity of 50°C for poly(o-methylstyrene), 45°C for poly(m-methylstyrene) and 40°C for poly(p-methylstyrene), respectively. In comparison with the model of a freely rotating methyl group, it is concluded that the mobility of the methyl group decreases from the para to the ortho position of the substituent. This result suggests that the trend of the steric hindrance between the hydrogens bonded to the methyl carbon and those in the backbone has an effect on the segmental motion and the rotation of the phenyl group. The finding that the activation energies for the segmental motion and the rotation of the phenyl group in poly(m-methylstyrene) were larger than those in poly(o-methylstyrene) and smaller than those in poly(p-methylstyrene) is in accord with the above suggestion.

Masuda, Toshio; Ohtori, Toshiyuki; Higashimura, Toshinobu

doi: 10.1295/polymj.11.849pmid: N/A

The hydration of double bonds along the main chain in poly(phenylacetylene) [poly(PA)] was undertaken via hydroboration. Soluble and high-moleular-weight poly(PA)s obtained with WCl6 and MoCl5 as catalysts were used as starting polymers. Hydroboration was usually performed in tetrahydrofuran at 50°C. The degree of hydration reached about 70%. Poly(β-naphthylacetylene) also underwent hydroboration in a similar manner, whereas no reaction took place for poly(1-phenylpropyne) because of steric hindrance. The product from poly(PA) was a white powder soluble in polar solvents such as ethyl acetate, acetone, and phenylethanols which are all non-solvents of poly(PA). The product was characterized by UV, IR, and 13C NMR spectroscopies.

Higashimura, Toshinobu; Hirokawa, Yoshitsugu; Matsuzaki, Kei; Kawamura, Tokiji; Uryu, Toshiyuki

doi: 10.1295/polymj.11.855pmid: N/A

The stereochemistry in the cationic polymerization of anethole, a β-substituted styrene, was investigated to clarify the propagation mechanism. The addition of acetaldehyde dimethyl acetal to anethole (acetal addition) was also studied as a model reaction. 13C NMR spectra showed that trans-anethole gave stereoregular polymers and that cis-isomer did not, indicating that the steric structure of the polymers depended on the geometrical structure of the monomer rather than on the polymerization conditions employed. On the other hand, the stereospecificity of the acetal addition was not very high even in the best case with trans-anethole (76% specificity). These results suggest that the structure of the attacking carbocation plays an important role in controlling the steric structure of products.

Toriumi, Hirokazu; Kusumi, Yoshiko; Uematsu, Ichitaro; Uematsu, Yoshiko

doi: 10.1295/polymj.11.863pmid: N/A

Thermally induced inversion of the cholesteric sense has been found in lyotropic polypeptide liquid crystals. The cholesteric sense of poly(γ-benzyl L-glutamate) liquid crystal in m-cresol (17 vol%) inverts from right to left at 60°C, and the reciprocal of the cholesteric pitch changes linearly with temperature. The compensated liquid crystalline solution at 60°C shows no helical twist. Similar phenomena are found for poly(γ-benzyl L-glutamate) in benzyl alcohol and for poly(γ-propyl L-glutamate) in m-cresol. The solvent effect on the helical twisting power is discussed in the light of the fact that the side-chain ester groups of poly(γ-benzyl L-glutamate) form hydrogen bonds with the hydroxyl groups of m-cresol.

Kunitake, Toyoki; Sakamoto, Tetsuo

doi: 10.1295/polymj.11.871pmid: N/A

The catalytic hydrolysis of p-nitrophenyl acetate was studied in water at 30°C in the presence of a polysoap-bound bifunctional (LIMHA) catalyst. The polysoaps used were poly(vinylimidazole) quaternized with dodecyl and ethyl groups and poly(ethylenimine) partly quaternized with methyl and higher alkyl (C8, C12, C18) groups. The catalysis proceeded via the acetyl transfer to the dissociated hydroxamate unit of the bifunctional catalyst and the subsequent decomposition of the intermediate by the neighboring imidazole. Catalysis was promoted well in the hydrophobic domain of the polysoap, but was less than that in the conventional cationic micelle of hexadecyltrimethylammonium bromide. The efficiency of the polysoap-bound bifunctional catalyst was ca. 1000 times greater than that of imidazole.

Chûjô, Riichirô; Tsuyama, Koichi

doi: 10.1295/polymj.11.879pmid: N/A

Catastrophe theory was successfully applied to the analysis of draw resonance phenomena. It was shown that the potential of cusp catastrophe was appropriate to the analysis of oscillating viscoelasticity appearing in the above-mentioned phenemena. Moreover, basic behavior such as stress relaxation is discussed in regard to this potential. In these analyses, no relaxation spectrum is introduced. However, an apparent spectrum can be obtained if the results of stress relaxation are analyzed by a procedure similar to that used in the analysis of linear viscoelasticity. But a spectrum may not always exist even if derived analytically.

Yamaoka, Kiwamu; Masujima, Tsutomu

doi: 10.1295/polymj.11.889pmid: N/A

By the combined equilibrium dialysis-colorimetric method, the fractions, f b, of bound Ni(II) and Cd(II) in the poly(α-L-glutamic acid)–Ni(II) and–Cd(II) solutions were determined at 25°C over a pH range of 7—4.2. Both Ni2+ and Cd2+ ions were dissociated by about 25% at pH 6.5 (f b≍75%), where poly(Glu) is in the random–coil form, and by nearly 90% at pH 4.5, where poly(Glu) is almost a complete helix. The ORD data of poly(Glu)–Ni(II) and–Cd(II) complexes were essentially the same as those of poly(Glu), indicating that these transition metal ions do not induce the helical structure in poly(Glu). This is a striking contrast with the case of Cu2+. From the equilibrium dialysis data, it was concluded that each Ni2+ or Cd2+ ion binds with two adjacent glutamyl residues in poly(Glu)–Ni(II) and –Cd(II) complexes. The stability constants of these complexes were estimated to be of the order of 103.

Yukawa, Joei; Kataoka, Kazunori; Tsuruta, Teiji

doi: 10.1295/polymj.11.895pmid: N/A

The copolymerization behavior of new styrene derivatives, namely, p-diethylaminoethylstyrene (p-EAS), m-diethylaminoethylstyrene (m-EAS), and p-vinylphenethyltriethylammonium bromide(p-VPAB), was examined. Copolymerization parameters of m-EAS were similar to those of styrene or m-methylstyrene, and a significant effect of the diethylaminoethyl group was observed in p-EAS. Q,e-Values of p-EAS were very close to those of p-dimethylaminostyrene. When P-EAS was copolymerized with acrylamide (AAm) in methanol, p-EAS exhibited a greater reactivity than AAm, which may be explained as a possible effect of the p-EAS causing an increase in the equilibrated concentration of the less reactive isomeric form of AAm. In the copolymerization of cationic monomer, p-VPAB, with MMA, p-VPAB exhibited less reactivity than MMA, owing to Coulombic repulsion between p-VPAB and the growing chain-end.

Hirano, Isamu; Einaga, Yoshiyuki; Fujita, Hiroshi

doi: 10.1295/polymj.11.901pmid: N/A