ポリ乳酸のモードI破壊挙動に及ぼす微視構造と負荷速度の影響(<特集>生体材料のバイオエンジニアリング)

概要

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Poly (lactic acid) was molded under four different kinds of condition to obtain samples with different microstructures. A single crystal was not observed in the specimen molded at 0℃. The size of spherulites became larger with increase of molding temperature. The density of spherulites increased with increase of molding time. Mode I fracture toughness, K_<IC> was measured at a static (1 mm/min) and an impact loading rate (1 m/s). K_<IC> became lower with increase of degree of crystallization at the static loading rate. This is mainly due to suppression of craze formation in the vicinity of crack-tip. On the other hand, at the impact loading rate, K_<IC> increased with increase of degree of crystallization. Thus, the results showed that crystallization has significant influence on K_<IC>, and its effect on the static K_<IC> was different from that on the impact one. Relationship between fracture toughness and fracture micromechanism was discussed on the basis of the results of fracture tests and microscopies.
一般社団法人日本機械学会の論文
2003-01-25