Mechanical and Creep Behavior of Polypropylene-Woodflour Composites

摘要

Although there have been various studies on the mechanical performance of lignocellulosic composites in the last decade, limited experimental results are available in creep. Considerations about the creep behavior of these materials are essential for some long-term applications. This work focuses on the study of the mechanical properties and creep behavior of polypropylene (PP)-wood-flour composites. The compatibility between filler and matrix was modified by esterification of the woodflour or by the addition of a PP-maleic anhydride copolymer (MAN) to the mixture. The samples were prepared by two different methods, injection and compression molding, and the filler content was varied from 0 to 60 wt%. Short-term creep data were obtained using a geometry of three-point bending. Creep deformation was reduced with woodflour addition, as well as by the addition of PPMAN. Compression molded samples showed less creep than injected samples because of different mixing and cooling times during process. Mathematical analysis of the short-term creep was performed using a simple four elements model, with very good agreement between calculated and experimental results. Long-term creep data showed a large improvement in the behavior of the samples by addition of the com-patibilizing agent.