SYNTHESIS AND CHAIN STRUCTURE OF ETHYLENE TEREPHTHALATE EPSILON-CAPROLACTONE COPOLYESTERS

A series of ethylene terephthalate-epsilon-caprolactone copolyesters ( TCL) with different hard segment contents were synthesized and charact erized by GPC, NMR, and DSC. The analysis from high-field H-1-NMR reve als that the transesterification between ET and CL segments during syn thesis is unavoidable, so TCL copolyesters are segmented copolyesters with certain random properties, as shown by the specific chemical and sequence structure of TCL copolyester chains and as confirmed by their crystallization behavior. The stress-strain test shows that TCL copol yesters with different hard segment contents may possess rubberlike or toughening plastic mechanical properties. (C) 1998 John Wiley & Sons, Inc.