Microstructural characterization of injection-molded articles

Authors

  • Musa R. Kamal,

    Corresponding author
    1. Department of Chemical Engineering, McGill University, Montreal, Canada H3A 2A7
    • Department of Chemical Engineering, McGill University, Montreal, Canada H3A 2A7
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  • Francis H. Moy

    1. Department of Chemical Engineering, McGill University, Montreal, Canada H3A 2A7
    Current affiliation:
    1. Technical Center, Union Carbide of Canada, P.O. Box 600, Pointe-aux-Trembles, Quebec, Canada H1B 5K8
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  • Corrected proofs received March 17, 1983

Abstract

The techniques of density, X-ray diffraction, and infrared dichroism measurements were employed to study anisotropic behavior, as a result of processing, in injection-molded parts. Data pertaining to the distributions of crystallinity and orientation indicated that significant changes occur at or near the surface of the molding. Generally, maximum density (crystallinity) is observed in the core of the molding and near the gate, while minimum density (crystallinity) is observed near the surface. X-ray diffraction suggests a complex pattern of orientation for the three crystallographic axes. The crystallographic a-axis tends to be oriented in the flow direction as indicated by both X-ray diffraction and infrared dichroism measurements. Generally, raising the molding temperature has only marginal influence on crystallinity and orientation. However, the two resins included in the study exhibited substantial differences in the distribution of these properties. The distributions of crystallinity and orientation are attributable to the complex interactions between resin properties and process conditions.

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