Title: Surface finishes in injection moulding of polymeric materials and composites

Authors: S.N.R. Choudhury, A. Edwards, M. Provatas

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

Abstract: The focus of the present study is to understand the effect of injection moulding process parameters on the surface finish of PC/ASA (polycarbonate/acrylonitrile-styrene acrylate) moulded parts through the analysis of both the bulk and surface chemical behaviours. Thermogravimetric analysis (TGA) provided information on material composition, thermal stability and decompositional behaviour, while Photoacoustic Fourier Transform Infrared Spectroscopy (PA-FTIR) was used to identify the effect of injection moulding on the chemical structure of the composite material. Microscopic analysis of surface defects was accomplished via Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Bulk analysis by TGA showed that the thermal stability of parts was lower when manufactured at extreme material temperature, injection speed and pack pressure. Surface chemical structure was found unchanged by PA-FTIR while SEM showed the surface topography of a defect known as ||pearlescence|| often present on grained parts. AFM successfully visualised the melt flow pattern and how it related to the surface finish on the moulded plaques.

Keywords: AFM; injection moulding; PA-FTIR; SEM; surface finish; thermal analysis.

DOI: 10.1504/IJMPT.2003.002508

International Journal of Materials and Product Technology, 2003 Vol.19 No.3/4, pp.228-246

Published online: 19 Jul 2003 *

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