Effect of microstructure and loading-rate on the mode I fracture behavior of poly (lactic acid)

Nobuyuki Shinohara, Mitsugu Todo, Kazuo Arakawa

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    2 Citations (Scopus)


    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°C. 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, KIC, was measured at a static (1 mm/min) and an impact loading rate (1 m/s). KIC 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, KIC increased with increase of degree of crystallization. Thus, the results showed that crystallization has significant influence on KIC, and its effect on the static KIC 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.

    Original languageEnglish
    Pages (from-to)95-101
    Number of pages7
    JournalNippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
    Issue number1
    Publication statusPublished - Jan 2003

    All Science Journal Classification (ASJC) codes

    • General Materials Science
    • Mechanics of Materials
    • Mechanical Engineering


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