TRANSESTERIFICATION AND RINGED SPHERULITES IN BLENDS OF BUTYLENE TEREPHTHALATE-EPSILON-CAPROLACTONE COPOLYESTER WITH POLY(EPSILON-CAPROLACTONE)

The miscibility, transesterification and formation of ringed spherulit es in blends of poly(epsilon-caprolactone) (PCL) with butylene terepht halate-epsilon-caprolactone (BCL) copolyester have been studied by d.s .c. and polarizing microscope. When the BT contents in copolyesters ar e below 60%, copolyesters are miscible with PCL. The compatibility bet ween components in the blends has a certain correspondence with the we akening of PCL crystallization ability in the blends. The transesterif ication can easily occur in the blends at 530 K. The transesterificati on depends on the miscibility between components and the BT content of the copolyesters, though the BT content plays a more important role i n the trans-reaction. Both copolyesters and transesterified copolyeste rs can evidently improve the formation of ringed spherulite in PCL/BCL copolyester blends. (C) 1997 Elsevier Science Ltd.