Synthesis and thermal characterization of crystallizable poly(caprolactone)/poly(hexamethylene terephthalate) block copolymer

An alternating multiblock copolymer of poly(epsilon -caprolactone) (PCL) an d poly(hexamethylene terephthalate) (PHT) with a 48/52 PCL/PHT composition weight ratio has been synthesized. Its structural and morphological paramet ers were measured using H-1 NMR, density measurements, differential scannin g calorimetry and its crystallization and melting were studied by real time simultaneous WAXS and SAXS using synchrotron radiation. These results are compared with those for the pure PCL and PHT used as building blocks. In th e crystallization conditions used here, the copolymer crystallizes as alter nate lamellae of PHT and PCL. The crystallinity of the PCL blocks is much l ower than that of pure PCL because they crystallize under stress in the sem i-crystalline PHT network. (C) 2001 Elsevier Science Ltd. All rights reserv ed.