PERIODIC RADIAL GROWTH IN RING-BANDED SPHERULITES OF POLY(EPSILON-CAPROLACTONE) POLY(STYRENE-CO-ACRYLONITRILE) BLENDS/

The isothermal crystallization process of a PCL/SAN blend (90/10 wt.-% ) was investigated by using real time image analysis and hot stage opt ical microscopy. It was found that the growth rate of ring-banded sphe rulites in the isothermal crystallization process is not constant. Slo w growth occurs in the bright bands, while fast growth is found in the dark bands. The radially unequal growth rate of ring-banded spherulit es in PCL/SAN blends may be related to the convex band structure on th e surface. This new discovery gives us the idea that rhythmic growth i s effective in the growth process of ring banded spherulites.