THE EFFECT OF HIGH-PRESSURE CARBON DIOXIDE TREATMENT ON THE CRYSTALLIZATION BEHAVIOR AND MECHANICAL PROPERTIES OF POLY(L-LACTIC ACID)/POLY(METHYL METHACRYLATE) BLENDS

摘要

The purpose of this study is to investigate the effect of carbon dioxide (CO{sub}2) on the crystallization behavior and the mechanical properties of PLLA and PLLA/PMMA blends with various weight fraction of PMMA. PLLA in the PLLA/PMMA blends can be crystallized even at a low temperature of 0°C under high-pressure CO{sub}2. The films treated with high-pressure CO{sub}2 at 0°C have about three times larger elongation at break than that of the amorphous film. The size of spherulites in the CO{sub}2 treated film is considered to be smaller than the wavelength of the visible light because of a good transparency. The improvement of the elongation at break is attributed to the reduction of the stress concentration during the deformation.