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Volume 33, Issue 6
Displaying 1-9 of 9 articles from this issue
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Hiroo TANAKA, Ryoichi SENJU1976 Volume 33 Issue 6 Pages 309-316
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe Hofmann degradation of polyacrylamide (I) was followed by the measurements of the hypochlorite (II), N-chloroamide (III), amino and carboxyl groups. In order to determine II and III separately, the difference in their reactivity with ethyl malonate was first utilized. Amino and carboxyl groups were measured by the colloid titration. The various factors on the yield of amine unit were also studied. The rate of the Hofmann degradation of I was a few hundred to a thousand and few hundred times as fast as that of low molecular monoamides or the carbamoyl derivatives of polyhydroxy-polymers. Therefore, chloroamide groups of I were easily converted to amine unit at 0--15°C, while other chloroamide groups generally are extremely stable at the similar temperature. The yields of amine unit increased with decreasing reaction temperature and increasing concentration of sodium hydroxide, e. g., the solution containing I (0.60mol/l), NaOCl (0.61 mol/l) and NaOH (4.5mol/l) produced the polymer containing ca. 90% amine unit when the solution was allowed to stand at 0°C for 24hr. Main side reaction was assumed to be the formations of urea derivatives and carboxyl groups. Sodium hypochlorite was more effective for the Hofmann degradation than sodium hypobromite.View full abstractDownload PDF (1550K) -
Shinzo YAMASHITA, Shinzo KOHJIYA, Hisao NAKAMURA1976 Volume 33 Issue 6 Pages 317-322
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESS1-Chlorobutadiene-butadiene rubber (I) was synthesized by the emulsion polymerization of 1-chloro-butadiene and butadiene. Three antioxidants carrying tertiary amino group were prepared as rubberbound antioxidants. One of these reactive antioxidants, N, N-dimethyl-N′-(4-hydroxyphenyl) -p-phenylenediamine (II), was allowed to react with I in toluene at 80°C. From the UV spectra of the reactants in cyclohexane, it was assumed that II was chemically bound to I, probably through the formation of quaternary salt of II with the chlorine attached to I. The reactive antioxidants were mixed with I compounds and cured with sulfur. The vulcanizates were extracted by chloroform/acetone/methanol, followed by aging in a Geer oven at 120°C. Tensile strengths of the vulcanizates before and after aging were measured. The vulcanizates of I compounded with commercially available antioxidants were used as references. The vulcanizates compounded with the reactive antioxidants were found to show much better resistance against deterioration after the extraction by solvent than those with commercial antioxidants. These results indicate that the antideterioration of rubber by using reactive antioxidants shows the feature which cannot be attained by using the commercial antioxidants. I is easily subject to this method and is expected to be of use as a new chemically functional butadiene rubber.View full abstractDownload PDF (1101K) -
Hidemasa OKAMOTO, Tadashi IWAI1976 Volume 33 Issue 6 Pages 323-329
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSEffects of O and a conventional antioxidant (I) were investigated on the gel formation, the decrease in vinyl groups and the mp lowering in the radiation-induced crosslinking and cyclization of syndio-tactic 1, 2-polybutadiene. O was found to retard the gel formation and to cause oxidation. Both the retardation of the gel formation and the oxidation were not serious when the specimen was thicker and electron beam was used in stead of γ-ray, but in reverse cases they became pronounced. While, in the case in which the oxidation took place markedly, the vinyl group decreased faster than the case of irradiation in vacuo. The gel formation and the decrease in vinyl groups were retarded by I and the G value for crosslinking decreased with the amount of I added. The mp lowering depended on only the gel fraction when oxidation was not remarkable. From these results, the roles of O and I in these reactions were discussed.View full abstractDownload PDF (1198K) -
Hidemasa OKAMOTO, Tadashi IWAI1976 Volume 33 Issue 6 Pages 331-338
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe radiation crosslinked and cyclized syndiotactic 1, 2-polybutadiene was heated at 225 to 325°C above the original mp in the absence of O2. Hard and transparent material was obtained by this treatment without melting and flowing above the mp. The cyclization of vinyl groups was suggested to be responsible for the above change. The vinyl groups decreased faster with increasing temperature and the rate of the decrease was much higher at the early stage than at the later stage. The heat cured product had amorphous structure, high specific gravity, high resistance to oxidation, remarkably high rigidity, high dielectric breakdown strength and arc resistance as elecrical property. A similar product was obtained when unirradiated polybutadiene powder was heated with a radical initiator at much lower temperature than the above. The decrease in vinyl groups in this cyclization was interpreted by a radical chain reaction and the mechanism was considered from the kinetical view point.View full abstractDownload PDF (1443K) -
Takeo ITO, Hideki SHIRAKAWA, Sakuji IKEDA1976 Volume 33 Issue 6 Pages 339-345
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSAcetylene polymers of any cis-trans composition were prepared by three different methods; (Type-1) by controlling polymerization temperature (-78-150°C) with Ti (OC4H9) 4-Al (C2H5) 3 system at constant Ti to Al ratio (Al/Ti=4), (Type-2) by controlling the ratio (Al/Ti=1-3) with the same catalyst system as Type-1 at constant temperature (0°C), and (Type-3) by thermal cis-trans isomerization of Type-1 cis polyacetylene prepared at -78°C. Structures of these polymers are discussed in terms of X-ray diffraction and density measurement. Type-1 polymers showed high crystallinities at any cis-trans composition in spite of random copolymers of cis and trans carbon-carbon double bonds, Type-2 polymers were less crystalline and seemed to be mixture of all cis and all trans polymers formed at different active sites, and Type-3 polymers were cis-trans random copolymers formed by solid-state isomerization.View full abstractDownload PDF (1310K) -
Jun-ichi YAMAKI1976 Volume 33 Issue 6 Pages 347-350
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA simple equation of tensile strength was derived, extending author's theory on discontinuous fiber composites. The equation expected the followings. If the composite tensile strength is a linear function of the fiber length as in the case of short fiber, the fracture mode of the composites is matrix mode or fiber/matrix interface debonding mode. In the latter mode, the tensile strength depends on the interface shear strength, while in the former, the tensile strength depends on the tensile modulus of the fiber. Experimental results on the dependence of fiber length distribution and fiber content on the tensile strength of the composites agreed with the equation. If the fiber orientation in the composites is known, the interface shear strength can be determined from the observed tensile strength.View full abstractDownload PDF (699K) -
Hajime SERITA, Chikai KIMURA, Koichi MURAI, Yukio TAKAHASHI1976 Volume 33 Issue 6 Pages 351-355
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPoly (vinylbenzylammonium chloride) was prepared by the reaction of poly (p-chloromethylstyrene) with tertiary amines with a view of obtaining good flocculants. The flocculating ability for aqueous suspensions of kaolin was investigated in relation to the structure of quaternary ammonium polymers by measuring the sedimentation velocity, sedimentation volume and residual turbidity. The experimental results revealed that trialkyl (C1-C4) amines were superior to heterocyclic amines (pyridine, α-picolin and N-methylpiperidine) in the preparation of good flocculants and quaternary ammonium polymers with the degree of quaternization of about 60% showed excellent flocculating abilities which are not inferior to that of typical commercial products.View full abstractDownload PDF (718K) -
Sumio YAMADA1976 Volume 33 Issue 6 Pages 357-360
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe permeation behavior of He, CO2 and N2 through the films of two different types of poly (vinyl acetate-vinyl alcohol) (I) was studied, one of which was prepared by partial saponification of poly (vinyl acetate) and of a block type and the other was obtained by re-acetylation from poly-(vinyl alcohol) and a random-type copolymer. The comparison of gas permeability coefficients in these I films of the same copolymer composition leads to the conclusion that the gas permeation rate through the block type copolymer was lower than that through the random type copolymer.View full abstractDownload PDF (733K) -
Tatsuro OUCHI, Shigeru NAKA, Minoru IMOTO1976 Volume 33 Issue 6 Pages 361-364
Published: June 25, 1976
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSCopolycondensation of p-hydroxybenzoic acid with p-aminobenzoic acid was carried out. The homopolymers and copolymers were not soluble in usual organic solvents, while they were soluble in concn sulfuric acid on heating. X-ray diffraction of copolymers showed a high crystallinity although lower than that of homopolymers. Differential thermal analysis and thermogravimetry indicated that these copolymers did not degrade below 510°C. The thermal stability increased with the increase of amide fraction.View full abstractDownload PDF (622K)
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