Thermal properties of poly(styrene-block-epsilon-caprolactone) in blends with poly(vinyl methyl ether)

The thermal characteristics of a styrene-epsilon-caprolactone diblock copol ymer, P(S-b-CL), in blends with poly(vinyl methyl ether) (PVME) were studie d by DSC. The glass transition temperatures show that PVME is only dissolve d in the PCL block. It segregates from the PCL block at low temperatures. T he addition of PVME leads to increasing crystallinity of the PCL block in a certain range of composition. However, degrees of crystallinity do not cha nge significantly with crystallization temperature. Optical inspection reve aled that the PCL block does not form spherulites. The crystallization kine tics of the PCL block has been systematically studied. The rate constants o f crystallization for different blends decrease exponentially with crystall ization temperature, whereas the rates of crystallization are scarcely affe cted by PVME content. The Avrami exponents were found close to two. (C) 200 0 Elsevier Science Ltd. All rights reserved.