Miscibility and spherulites in blends of poly(ϵ-caprolactone) with ethylene terephthalate-caprolactone copolyester

Abstract

The miscibility of blends between poly(ϵ-caprolactone) (PCL) and ethylene terephthalate-caprolactone copolyester (TCL) with different ethylene terephthalate (ET) contents has been studied by differential scanning calorimetry. When ET contents in the copolyesters are less than 30%, the copolyesters are miscible with PCL. The TCL48 and TCL58 copolyesters were partially miscible with PCL and had an evident influence on the formation of ringed spherulites of PCL in the blends. This means that the addition of a non-crystallizable component with partial miscibility is important for enhancing the formation of PCL ringed spherulites. Transesterification in PCL/TCL blends can also affect the formation of ringed spherulites. There is a best extent of transesterification under which the patterns of ringed spherulites are most distinct. Such a phenomenon may be related to the improvement of miscibility of PCL with TCL copolyesters and composition homogenization in the blends.