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Volume 38, Issue 11
Displaying 1-9 of 9 articles from this issue
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Kenji OKUNO1981 Volume 38 Issue 11 Pages 749-755
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSFor the composites of stylene-acrylonitrile copolymer (AS) filled with platelet-shaped reinforcements (mica, glass flake), the critical strain energy release rates, Gc, were determined from the Charpy impact values. The results were compared with those of glass fiber filled AS. The critical strain energy release rate of reinforcements, (Gc) f, calculated by a mixture law, increases with the volume fraction of reinforcements, Vf, and ll2/d of reinforcements. Here l is the flake diameter or the fiber length and d is the flake thickness or the fiber diameter. However, the (Gc) f value for flake composites is about half of that of fiber composites at the equivalent Vf and ll2/d. The results are explained by Cottrell's equation for fiber composites, and by modified Cottrell's equation for composites with rectangular shaped flakes, if the pull-out of the reinforcements for the mode of failure is assumed.View full abstractDownload PDF (2554K) -
Makoto SHIRAISHI, Kiyokazu IMAI, Masakzau MATSUMOTO1981 Volume 38 Issue 11 Pages 757-762
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDegradation of poly (vinyl alcohol) (PVA) under radio-irradiation in air was investigated to see whether the resulting carbonyl groups were produced by chain scission or by chemical reactions in main chain. The irradiation of PVA in power increased terminal carbonyl and keto type of carbonyl in main chain whereas the increase in the amount of carboxyl group was small. The scission took place via the oxidative intermediate, ketocarbonyl in the main chain, or via a pathway involving no oxidative, reaction. In the irradiation of PVA in aqueous solution, the degree of polymerization and the carbonyl content of PVA increase, where the carbonyl groups were dominantly formed in the main chain.View full abstractDownload PDF (941K) -
Kunio NAKAMURA, Tatsuko HATAKEYAMA, Hyoe HATAKEYAMA1981 Volume 38 Issue 11 Pages 763-767
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSFactors affecting the molecular motion of styrene-hydroxystyrene copolymers were studied. Glass transition temperature (Tg) of copolymer increased with increasing amount of hydroxyl group. Main chain motion of the copolymer was affected by absorbed water: Tg of the copolymer decreased with increasing amount of absorbed water. By applying the mixture rule reported by Wood and Fox to the copolymer-water, it was found that the lowering of Tg by absorbed water was due to the plasticizing effect and also to breakage of hydrogen bonds among the polymers. The amount of hydrogen bonding between the hydroxyl groups was estimated quantitatively from the relation between the amount of absorbed water and the lowering of Tg of the copolymer.View full abstractDownload PDF (842K) -
Katsuo ORIHARA, Saiji HIGUCHI, Masakazu MATSUMOTO1981 Volume 38 Issue 11 Pages 769-773
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe effects of poly (vinylpyrrolidone) (PVP) on the reactions of 2, 4-dinitrochlorobenzene with NaOH (1) and with cyclohexylamine (2), and of 2, 4-dinitrofluorobenzene with NaOH (3) and with cyclohexylamine (4) were studied. PVP enhances all the reactions, and the enhancement depends upon the concentration and the molecular weight of PVP. In the range of molecular weight of PVP examined, 2.1-200×104, the enhancement is the highest at Mv=2.1×104, then it decreases gradually with an increase of the molecular weight. Since N-methyl-2-pyrrolidone, a model compound of PVP unit, exhibits little enhancement, the maximum enhancement must lie in the neighbourhood of the molecular weight 2.1×104. The enhancement becomes substantial from the concentration, 10-3-10-2mol/l, and increases with the concentration up to 0.76mol/l, the highest concentration examined. The order of the enhancement in the four reactions is (1) >> (3), (4), (2). When ethanol is added to the reaction (4) system, the effect of PVP is subdued. This supports that the hydrophobic interaction between the substrate and the polymer chain is a factor of the enhancement. The above four reactions are also accelerated by poly (ethylene glycol), but decelerated by poly (vinyl aclohol).View full abstractDownload PDF (914K) -
Katsuo ORIHARA, Masakazu MATSUMOTO1981 Volume 38 Issue 11 Pages 775-780
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe effects of poly (vinylpyrrolidone) (PVP) on hte alkaline hydrolysis of p-nitrophenyl esters were studied. As ester, p-nitrophenyl acetate, caproate and laurate were used. As PVP, commercial products and the home made samples were Used. The range of malecular welght of PVP examined is between 1.1×104-140×104. The alkaline hydrolysis rate is enhanced by PVP and the enhancement is linear to [OH-] in the concentration range 2×10-0-5×10-4mol/l. The enhaneement appears above a PVP eoncentration, 0.01wt% and increases sharply above 0.1wt%. The enhanCement depends on Mv of PVP to show a maximum between 1×104-5×104 of Mv, When the hydrocarbon group in esters becomes longer, i. e., the hydrophobicity of the ester increases, the enhancement by PVP becomes larger. The reason for the enhancemnt of PVP may be the increased local concentration of both the substrate ester and OH- in the aqueous reaction system. The reactions are also accelerated by poly (ethylene glycol), but decelerated by poly (vinyl alcohol).View full abstractDownload PDF (1064K) -
Yoshiyuki IKEDA, Kazuo NISHIMURA, Masahiro KAWATA, Yasuaki KOZAI1981 Volume 38 Issue 11 Pages 781-786
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe polymerizations of methacryloyl amino acids (alanine, valine, β-alanine and ε-amino-n-caproic acid) were carried out in aqueous solutions and the pH dependence of the rate of polymerization (Rp) was investigated. In the polymerization using ammonium persulfate (APS) as an initiator, Rp increased rapidly with increasing pH for each monomer in acidic solutions, and became practically constant above pH 7. The pH dependence of Rp was similar to that of the decomposition rate of APS. When azobisisobutyronitrile was used instead of APS, the pH dependence of Rp was almost identical with that in the case of APS, although Rp was considerably smaller. Rp for each monomer was proportional to the monomer concentration and to the square root of the APS concentration regardless of the pH. The pH dependence of Rp for methacryloyl amino acids differed merkedly from that for acryloyl amino acids.View full abstractDownload PDF (927K) -
Mitsuru UEDA, Toshiaki HARADA, Katsuhiko HIRATA, Yoshio IMAI1981 Volume 38 Issue 11 Pages 787-790
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSNew active diamides, N, N'-isophthaloylbis-2-benzoxazolone (III) and N, N′-adipoylbis-2-benzoxazolone (IV), were synthesized from the corresponding diacyl chlorides and 2-benzoxazolone (I). The solution polycondensation of the active diamides with diamines afforded polyamides with moderate molecular weights, where 1-hydroxybenzotriazole showed strong catalysis. The aminolysis of N-ben-zoyl-2-benzoxazolone (II) was studied to shed light on the mechanism of the polycondensation.View full abstractDownload PDF (635K) -
Takakazu KOJIMA, Toshinori NAKAMURA, Yoshinobu HOSAKA1981 Volume 38 Issue 11 Pages 791-796
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSVarious random and ordered copolymers of poly (phenylene phthalamide) were synthesized. The monomerunit composition in the main chain was determined by IR spectrometry and proton NMR techniques. Relations between the structure and the thermal stability evaluated by thermogravimetry-differential scanning calorimetry (TG-DSC), were studied.
With regard to random copolymers, the peak temperature of the DSC curve increased with the fraction of para-linkage in the main chain, and the thermal decomposition temperature obtained from the TG curve increased with the mole fraction of terephthaloyl chloride in feed, though the random copolymers practically consisted of higher fraction of para-linkage. The thermal decomposition temperature of a random poly (phenylene phthalamide) copolymer was lower than that of the ordered copolymer containing the same fraction of para-linkage as the random copolymer.
These results suggest that a thermal decomposition of a locally disordered linkage in a random copolymer chain accelerates decompositions of other linkages which would otherwise have higher decomposition temperatures, thereby leading to the decomposition of the whole molecular chain.View full abstractDownload PDF (995K) -
Seiichi KATAOKA, Tadanao ANDO1981 Volume 38 Issue 11 Pages 797-799
Published: November 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe living radical Polymerization of sodium methacrylate (MAA·Na) was carried out in an aqueous solution at 30°C using potassium persulfate as an initiator in the presence of chitosan acetate salt (CS·AcOH) with a CS·AcOH/MAA·Na molar ratio of 1.0. The dependence of the number average degree of polymerization and/or polydispersity (Mw/Mn) of methyl esters of the obtained poly (methacrylic acid) on the corresponding values of chotosan (CS) were investigated by CPC analysis. The unimodal peak of the GPC curves of the obtained polymers shifted toward low elution counts (high molecular weight) with increasing in conversion, and Mw/Mn were independent of the conversion. When the conversion in the polymerization was close to 100%, the number average degree of polymerization and Mw/Mn of the obtained polymers were almost identical with these values of CS. It was suggested that CS moleculus could act as a polymer matrix.View full abstractDownload PDF (484K)
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