NaBF4 as a hygrothermal durability enhancer for glass fibre reinforced polypropylene composites

Abstract

The long term performance of composite materials is highly desired for their expanding application range. Tuning the interphase properties has been proven to be a practical way to enhance the performance of composites. In this study, short glass fibre (GF) reinforced polypropylenes (PPs) with improved hygrothermal durability were obtained by incorporating NaBF 4 into the sizing and thus the interphases of GF/PP composites. Detailed investigations were performed on the surface properties of sized GFs and the mechanical properties of virgin and aged composites. It was found that the retention in both ultimate tensile strength and Charpy impact toughness of aged composites monotonically increased with increasing NaBF 4 content. The improvement in hygrothermal durability was related to the enhanced fibre/matrix adhesion strength induced by the presence of NaBF 4 as indentified by fracture surface analysis using field-emission scanning electron microscopy and single fibre pull-out test.