Polypropylene-block-poly(ethylene-co-propylene) addition to polypropylene/poly(ethylene-co-propylene) blends: morphology and mechanical properties

The additive effects of a diblock copolymer of polypropylene and ethylene-p ropylene rubber PP-b-EPR(50-50) on the morphology and mechanical properties of PP/EPR(50/50) blends were investigated. It was found from an electron m icroscopy study that the block copolymer is compatible with the PP phase bu t incompatible with the EPR phase. Dynamic mechanical spectra showed that t he PP-b-EPR block copolymers are incorporated into the PP phase, and conseq uently, the EPR portions of the block are trapped into the interlamellae of PP. (C) 2000 Elsevier Science Ltd. All rights reserved.