Visualization of surface and subsurface morphology: The effect of processing on a rubber-modified thermoplastic

Authors

  • S. A. Edwards,

    1. Polymer Science Sector, Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095, Australia
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  • N. Roy Choudhury,

    Corresponding author
    1. Polymer Science Sector, Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095, Australia
    • Polymer Science Sector, Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095, Australia
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  • M. Provatas

    1. Polymer Science Sector, Ian Wark Research Institute, University of South Australia, Mawson Lakes Boulevard, Mawson Lakes, SA 5095, Australia
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Abstract

In typical injection-molding processes, variation in the quality of the surface finish is often encountered. To understand the mechanism of common surface defect formation, we investigated the effect of processing parameters on the morphological features of a commercially supplied polycarbonate/acrylonitrile–styrene–acrylate rubber-modified thermoplastic blend. A compositional analysis of the material was performed with thermogravimetric analysis. Acid and alkaline etching, in conjunction with scanning electron microscopy, was used to characterize the effect of various injection times, packing pressures, and material temperatures on the morphology of processed parts. Chemical etching revealed that the injection molding had a large influence on the morphology of the thermoplastic, particularly on the surface, where preferential phase segregation produced a highly oriented polycarbonate skin layer. The degree of molecular orientation on the surfaces of molded parts had a significant effect on the efficiency of both the acid- and alkaline-etching techniques. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 774–786, 2003

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