MECHANICAL-PROPERTIES OF INJECTION-MOLDED STYRENE-MALEIC ANHYDRIDE (SMA) - PART I - INFLUENCE OF WELDLINE AND REPROCESSING

This paper presents the results from the first part of a study on the influence of reprocessing and weldlines on the properties of styrene m aleic anhydride (SMA) polymer. Specimens for this study were injection moulded and reprocessed up to five times. It was found that while mec hanical properties such as strength and modulus in both tension and fl exure tests were virtually independent of the number of reprocessing c ycles, the energy to fracture decreased as a result of reprocessing. F racture parameters such as fracture toughness and strain energy releas e rate also showed little variation with reprocessing; although at tim es a reduction in these parameters was obtained for the fifth cycle. W e found that tensile strength, fracture energy and fracture toughness were all reduced substantially in the presence of the weldline. Howeve r, none of these properties showed any significant variation with the number of reprocessing cycles. (C) 1998 Chapman & Hall.