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Volume 38, Issue 2
Displaying 1-8 of 8 articles from this issue
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Isao SASAKI, Fumio IDE1981 Volume 38 Issue 2 Pages 67-74
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn order to improve the reinforcement of glassfiber for polypropylene, polypropylene was grafted with unsaturated carboxylic acid in the presence of radical initiator by melt-mixing method in an extruder. As the radical initiator, benzoyl peroxide and dicumyl peroxide exhibit high grafting activity, however azobisisobutyronitrile and lauroyl peroxide exhibit poor grafting activity. The machanical properties and heat resistance of glassfiber-reinforced polypropylene are remarkably improved by the grafting with a small amount of an unsaturated carboxylic acid or a carboxylic anhydride such as acrylic acid or maleic anhydride. Improvements in the low-temperature impact strength, creep properties, and modulus of rigidity by the grafting are valuable for practical use. The grafting effects are also determined in the case of polypropylene filled with glassfiber and calcium carbonate. A warp and a shrinkage of mold article are improved without decreasing the mechanical properties.View full abstractDownload PDF (1489K) -
Isao SASAKI, Fumio IDE1981 Volume 38 Issue 2 Pages 75-83
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMechanism for reinforcement of glassfiber in polypropylene grafted with unsaturated carboxylic acid was investigated. Reinforcing effect of glassfiber is affected by adhesion between polypropylene and glassfiber, aspect ratio, uniformity of glassfiber dispersed, and crystal structure of polypropylene. In these factors, the increase of adhesion is most effective for reinforcement. Polypropylene grafted with unsaturated carboxylic acid exhibits good adhesion to glassfiber coupled with amino-silane or epoxy-silane to improve the mechanical strength and heat resistance. Adhesion between glassfiber coupled with vinyl-silane and polypropylene graftedis poor. Reinforcing effect increases with increasing the aspect ratio of glassfiber. Uniformity of glassfiber dispersed increases with decreasing melt viscosity of polypropylene. Polypropylene with high crystallinity and small spherulite exhibits good properties. This is due to the fixing effect of crystal for glassfiber. Improvement of adhesion is also effective for decreasing the shrinkage of mold article, which, however, results in void formation.View full abstractDownload PDF (3195K) -
Toshihiro KASHIMA, Kuniomi ETOH1981 Volume 38 Issue 2 Pages 85-93
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe crystallinity of poly (ethylene terephthalate) or poly (buthylene terephthalate) copolyester containing adipic acid, isophthalic acid or poly (tetramethylene glycol) has been studied by differential scanning calorimetry (DSC). It was found the poly (buthylene tereisophthalate) and poly (ethylene tereisophthalate) shows maximum and minimum crystallinity, respectively, among the polyesters. In addition, isothermal crystallization rate was found to have a relation to the rate of crystallization at a constant cooling rate. But the relationship depends on the molecular weight; with decreasing molecular weight, crystallization rate increases.View full abstractDownload PDF (1294K) -
Masayuki KASAJIMA, Kunihiro FUKUSHIMA, Katsuhiko ITO1981 Volume 38 Issue 2 Pages 95-101
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMechanical properties were measured for the dispersed composite polymers composed of a highdensity polyethylene (HDPE) resin and polystyrene (PS) resins of different grade. No additivity was found for bending stress (σb), compressive strength (σc), and deflection (δ). The σb of blended sample depends strongly, with increase in δ, on the σb of HDPE. Temperature dependence of σb for blended sample is influenced strongly by the temperature dependence of σb for the HDPE. The δ of blended sample depends strongly on the deflectivity, of the HDPE at the lower temperature range measured in this study, but of the PS at higher temperature. The σc of blended sample depends on the σc of the HDPE. Such dependence is larger for σc than for σb.View full abstractDownload PDF (1186K) -
Hiroshi SAKAMI, Toyohiko IZUSHI, Shozo IIDA1981 Volume 38 Issue 2 Pages 103-110
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSFibrillar films of high-molecular-weight polyethylene crystallized by stretching above the melting point were found to have three crystalline components different in morphology. Their melting behaviours were thought to be influenced by the taut molecular chains which were left uncrystallized under an inhibitory effect of entanglement. In order to learn the melting behaviour of the crystalline components free from the influence of the noncrystalline chains, differential scanning calorimetry (DSC) measurements were carried out on those films which had been treated with 77% fuming nitric acid at 60-118°C or with γ-ray dose for 90 Mrad. Comparison of the DSC curves for these films with those for the untreated ones showed that the higher was the degree of the orientation of the crystallites, the greater was the influence of the noncrystalline chains on the melting behaviour. The melting point of the extended-chain crystal in the nitric-acid treated sample was 144.7°C and its dimension (along c-axis) was estimated as 2.1×103A by use of the equilibrium melting point TTm0=146.5°C. With samples subjected ta γ-ray irradiation followed by heat treatment, DSC showed clearly that three crystalline components, namely fine crystallite, highly-oriented crystal and extended-chain crystal. Percentagewise, their quantities were 60.6, 35.6, and 3.8 respectively. The extended-chain crystal had a meliting Point at 145.5°C and the size was calculated at 2.8×103A.View full abstractDownload PDF (2582K) -
Katsutoshi TANAKA1981 Volume 38 Issue 2 Pages 111-117
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPoly (vinyl chloride) (PVC) filled with powders of ground glass (GGP) and glass fiber (GFP) in the range of 0-80 vol%, has voids around the glass particles. The volume fraction of voids increases abruptly at certain volume fractions of fillers (φf), 0.5 for GGP and 0.4 for GFP and φf reaches the maximum packing values (φfm), 0.67-0.69 for GGP and 0.61-0.63 for GFP. Dynamic mechanical properties of the composite materials were measured over the temperature range from room temperature to about 130°C. The enhancement of the glass-transition temperature (Tg) is small below 0.3 of φf, while it gets hlgher near the φfm. The relative modulus (Er′) is less than 2 in glassy region, and is lower than the value estimated from the modified Halpin-Tsai equation, using modified Einstein coefficient (kE) of 2.5 for GGP and 6.0 for GFP. In rubbery region, Er′ increases with an increase of φf. The values of Er′ reproduces the Mooney equation at 0.4 of φf for GGP and 0.2 for GFP.View full abstractDownload PDF (3672K) -
Yoshiaki HIRABAYASHI, Shigeki TAKAYAMA, Yasuji OHTSUKA1981 Volume 38 Issue 2 Pages 119-125
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPoly (vinyl alcohol) -acrylonitrile-2-hydroxyethyl methacrylate graft copolymer latex membrane is an amphiphilic material owing to the well-balanced composition of hydrophilic and hydrophobic components. The membrane has excellent mechanical properties in wet state, solute permeabilities and blood compatibility compared with those of Cuprophan PT-150, whereas water permeability is inferior to that of Cuprophan PT-150. Therefore, some attempts have been made to improve the water permeability of the membrane with the predominant characteristics retained. The water permeability was improved significantly by the following treatment: the graft copolymer latex membranes were immersed in single or mixed solvents of dimethylformamide and dimethyl sulfoxide after extraction with water at 80°C for 48 hours, and then dipped in water. It was found that the membranes, once swelled in the solvents and subsequently deswelled in water in the above procedure, were provided with microfractures at the interface between continuous and disperse phases in the membrane. The permeation mechanism of the resulting membranes was elucidated according to the capillary model.View full abstractDownload PDF (3608K) -
Kimio SHINDO1981 Volume 38 Issue 2 Pages 127-132
Published: February 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThermally-stimulated polarization current was measured for poly (ethylene terephthalate) film. When the freshly-annealed film was heated under the application of a high field, the current was positive at the beginning and turned negative at an intermediate temperature and then returned positive. In the successive cooling, a positive current was observed. Then the test piece was heated again and a negative current was observed until high temperature where ohmic current prevailed. These phenomena can be explained by considering the displacement current due to polarization: the saturation values in polarization for every relaxation mode are inversely proportional to temperature and hence polarizations increase by cooling and decrease by heating.View full abstractDownload PDF (890K)
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