Thermoplastic elastomers based on compatibilized poly(ethylene terephthalate) blends: effect of rubber type and dynamic curing

Thermoplastic elastomers containing poly(ethylene terephthalate) (PET) in 5 0 wt%, compatibilizer (glycidyl methacrylate grafted rubber or glycidyl met hacrylate containing copolymer) in 30 wt% and various rubbers (20 wt%) were produced by melt blending with and without dynamic curing (dicumyl peroxid e initiated). The static tensile (stress-strain behaviour) and dynamic mech anical thermal properties (DMTA) of the systems along with their phase morp hology (scanning electron microscopy of cryofractured and etched surfaces) were determined. It was found that the blend compatibility with PET is stro ngly improved when a high acrylonitrile-containing nitrile rubber (NBR) and an ethylene-glycidyl methacrylate copolymer (EGMA) or a GMA grafted ethyle ne/propylene rubber (EPR-g-GMA) are used as rubber and/or compatibilizer in the blend recipes. The effect of dynamic curing on the tensile and DMTA pr operties of the blends was negligible. Fractographic inspection of the frac tured surface showed the development of a co-continuous phase structure whi ch was in accordance with learnings from the DMTA spectra. (C) 2000 Elsevie r Science Ltd. All rights reserved.