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Abstract: The present study presents a method to predict the flow distribution imposed on an injection moulded melt crystallised isotactic polypropylene (iPP) from its experimentally determined morphological distribution. A microrheological model, based on the Doi–Edwards model, was used to calculate the flow-induced free energy for the flow-induced crystallisation. The low limit flow field required to generate the final structures was then obtained. The effect of Cu-phthalocyanine (CuPc), a nucleating agent, on the flow history was also studied. Instead of geometric positions, structural parameters such as molecular orientation and crystallinity were correlated to the flow history of the injection-moulded iPP. The work provides a simple approach to predict flow–structure relationships for complex thermo-mechanical processing treatments, which can then guide the realistic design and control of the flow-induced crystallisation of polymers. [Copyright &y& Elsevier]

Abstract: The morphology of isotactic polystyrene (iPS) particles which had been compounded into an isotactic polypropylene (iPP) matrix was varied in-situ by selective heat treatment to be either amorphous (iPSamorphous) or semicrystalline (iPScrystalline). The influence of iPS morphology on the quiescent and shear-induced isothermal crystallisation of iPP was then studied using differential scanning calorimetry (DSC), in-situ simultaneous small and wide angle X-ray scattering (SAXS/WAXS) and polarised optical microscopy (POM). In the quiescent condition iPScrystalline was found to selectively nucleate the β phase while iPSamorphous nucleated the α phase of iPP. Compared to the control sample (iPPcontrol), the presence of both morphologies of iPS increased the number of shear-induced oriented crystal precursors that form as a result of the step shear. During isothermal crystallisation the shear-induced nuclei promote oriented α form crystal growth, accelerate the crystallisation kinetics and ultimately swamp the effect of the nucleating particles present. [Copyright &y& Elsevier]