The relationships between morphology, irradiation and the ductile-brittle transition of isotactic polypropylene

The effect of the morphology of polypropylene, as controlled by annealing, on the material's micro-mechanical response before and after irradiation is explored using simultaneous SAXS/tensile deformation experiments, Morpholo gy moderates the effects of cross-linking and scission on the deformation b ehaviour. The micro-mechanisms of deformation can be related to these morph ological and chemical changes. It appears that a high tie-chain density and a low crystal thickness, which may be achieved by crystallisation at low t emperatures, will encourage resistance to mechanical property deterioration under irradiation. (C) 1999 Society of Chemical Industry.