EFFECTS OF ANNEALING TIME AND TEMPERATURE ON THE CRYSTALLINITY AND DYNAMIC MECHANICAL BEHAVIOR OF INJECTION MOLDED POLYLACTIC ACID (PLA)

摘要

The effects of annealing time and temperature on the crystallinity of poly(lactic acid) (PLA) were investigated. The degree of crystallinity observed after short annealing times resembled those observed at cooler temperatures, suggesting a time-temperature superposition relationship. Crystallinity isotherms in the logarithmic scale were shifted horizontally along the log-time axis and a master curve was constructed. Dynamic mechanical analysis showed that an increase in crystallinity increased the glass transition temperature and improved the storage modulus.