Role of Coupling Agents on the Performance of Woodflour-Filled Polypropylene Composites

Abstract Composite materials were prepared from waste woodflour and polypropylene (PP). In order to enhance the chemical affinity between hydrophilic woodflour and hydrophobic polymer, the surface of the filler was modified by coating with a mixture of PP and a polymeric isocyanate, while PP was mixed with two types of maleated PP, before being mixed the woodflour with polymer. The effects of coupling agents (i.e., individually or their mixtures) on the mechanical properties and void content of the composites have been evaluated. In the presence of coupling agents the composites showed superior mechanical properties compared to those of non-treated composites and to those of unmodified polymer. The extent of improvement in mechanical properties depends on the nature, addition levels, and compositions of coupling agents. As far as mechanical properties of the composites were concerned, the mixtures of coupling agents showed better performance compared to those of coupling agents used individually.