Effects of the structure of styrene-co-maleic anhydride oligomers on the interfacial properties in a glass fibre reinforced polystyrene composite material

Styrene-co-maleic anhydride oligomers with molecular weight ranging from 1600 to 1900 g/mol have been added to glass fibre reinforced polystyrene as interfacial modification agents. It has been observed that the presence of oligomers improves the mechanical resistance of the composite materials after the incorporation of less than 1 % in weight. Above 1 %, the mechanical properties increase slightly, then a progressive decrease of the mechanical resistance is recorded. The maximum is noted when the oligomer content is close to 1.5 %. The maleic anhydride content in the oligomer is a parameter which also plays an important role for the mechanical behaviour of the composite material. In this case, the increase in the maleic anhydride content allows an optimal covering of the glass fibre surface, and a significant improvement of the mechanical properties of the composite is observed. A model of surface covering of fibres is developed to explain this phenomenon. (C) 2002 Elsevier Science Ltd. All rights reserved.