SEM studies of tensile fracture surfaces of polypropylene - sawdust composites

Composites of polypropylene (PP) or PP plus maleated polypropylene (MAPP) and sawdust coated with 22.4 wt% MAPP were prepared under fixed processing conditions (mixing temperature, rate of rotation and mixing time). The tensile properties and the fracture mechanisms of the composites have been studied. The effect of MAPP content on the properties of PP mixes were also studied. Scanning electron microscopy (SEM) was performed to analyze the tensile fracture surfaces and the interfacial fiber/matrix adhesion. The tensile properties of composites with up to 10% MAPP have not been improved by increasing MAPP content. This has been attributed to the poor filler/matrix adhesion. The addition of higher MAPP content to the PP composites produces better adhesion of sawdust to PP matrix and an increase in the tensile strength. (C) 2003 Elsevier Science Ltd. All rights reserved.