Compression yielding of polypropylenes above glass transition temperature

Abstract: Yielding behaviour under compressive loading of two materials based on polypropylene, an isotactic homopolymer and an ethylene–propylene block copolymer, is studied at different strain rates and temperatures. Quasi-static tests, performed in electromechanical machines, and dynamic tests, carried out in a Hopkinson bar, were compared and simultaneously analyzed to generate a master curve representative of the material yielding, assuming the strain rate-temperature superposition principle. Experimental data were fitted to equations based on the cooperative model for semi-crystalline polymers. [Copyright &y& Elsevier]