STEREOCOMPLEX FORMATION IN AB DI-BLOCK COPOLYMERS OF POLY(EPSILON-CAPROLACTONE)-(A) AND POLY(LACTIDE)-(B)

The thermal properties of two series of AB di-block copolymers of poly (epsilon-caprolactone) (A) and poly(lactide) (B) and their blends were studied. Each series contained poly(lactide) blocks of opposite chira lity. The length of the poly(epsilon-caprolactone) blocks was not vari ed (DP = 70), whereas the poly(lactide) blocks were of varying length (DP = 5 - 80). Blends of polymers containing blocks of opposite chiral ity were prepared by mixing in solution. The melting temperature of th e PLA phase was raised by approximately 55 degrees C in the blends due to stereocomplex formation. The melting temperatures of the crystalli ne PCL and PLA phases strongly depended on the composition of the bloc k copolymers.