In situ compatibilization of polyurethane with poly(ethylene terephthalate)

Melt-mixed blends of a polyester type polyurethane (PU) with poly(ethylene terephthalate) (PET) were characterized by tensile testing, dynamic mechani cal analysis, optical and electronic microscopy and solution H-1-NMR. Mecha nical and thermal properties indicated good blend compatibility typical of a polymeric alloy. Morphology examination revealed good dispersion and stro ng interface adhesion. H-1-NMR of blends showed the formation of a PET-PU c opolymer by ester-amide interchange reaction whose extent depended on the P ET/PU ratio and melt mixing conditions. This in situ formed copolymer is re sponsible for the reactive compatibilization observed. (C) 2000 Elsevier Sc ience Ltd. All rights reserved.