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THE MICRO STRUCTURE OF ETHYLENE VINYL ALCOHOL COPOLYMER

1974; Volume: 30; Issue: 8 Linguagem: Inglês

10.2115/fiber.30.8_t391

1884-2259

Tsunetaka Matsumoto, Katsuhiko Nakamae, Hideaki Oka, Seigi Kawarai,

Engineering Applied Research

In order to show the relationship between the micro structure of crystalline ethylene vinylalcohol (EVA) copolymer and the copolymer component, the density and the thermal expansion of crystalline part and the behavior of hydroxyl group were studied for the EVA copolymers with various components.The following results were obtained: (1) The crystalline density of EVA copolymer observed by a floatation method was smaller than that evaluated from its unit cell at vinylalcohol (VA) contents under 20 mol%. For the other EVA copolymer with VA contents above 20 mol%, the larger crystalline density compared with the density by calculation from unit cell was always observed, and the VA concentration in the crystalline phase was larger than that of over all copolymer components. (2) According to infra-red spectrum for the hydroxyl group, at VA contents above 30 mol%, the hydrogen bonds were almost formed. (3) The thermal expansion of crystal for EVA copolymer were larger than those of PE and PVA. The expansion of the a axis direction was particularly larger than those of the other directions. From these data, it is reasonable to consider that the hydrogen bond was formed along this direction. (4) The thermal expansion coefficient of EVA copolymers containing VA 20 to 60 mol% was about 2 to 3 times that of EVA copolymer in other ranges of VA contents.