Effect of reprocessing on mechanical properties of short glass fibre reinforced styrene maleic anhydride

The effect of reprocessing by injection moulding on the mechanical properti es of styrene maleic anhydride composites reinforced with 10, 20, and 30 wt -% short glass fibres has been studied. The study revealed that matrix prop erties related to the breaking point were significantly reduced by reproces sing. The observed reduction in the property values of the matrix material was attributed to the reduction in ductility caused by the molecular weight degradation. For the composites, almost all measured properties were reduc ed as a consequence of reprocessing. The strength and modulus of the compos ite were found to be linear functions of both the average length and the co ncentration of the fibres in the composite. The reduction in composite prop erty values was attributed mainly to the degradation of fibres during each reprocessing cycle. Using a modified rule of mixtures, values of the overal l efficiency parameter for strength and modulus were estimated and found to decrease as the number of reprocessing cycles was increased. This reductio n in the overall efficiency parameters was mainly due to fibre breakage, oc curring at each reprocessing cycle. PRC/1619 (C) 2000 IoM Communications Lt d.