INFLUENCE OF IMPACT MODIFIER AND COUPLING AGENT ON IMPACT STRENGTH OF WOOD FLOUR / RECYCLED PLASTIC COMPOSITES

Abstract

In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP) composites was investigated. The PP (virgin and recycled polypropylene) and wood flour (WF) were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA) and ethylene/propylene/diene terpolymer (EPDM)), to produce wood flour-PP composites specimen. The results showed that the composites containing recycled PP exhibited significantly lower impact strength values than those of containing virgin PP. The addition of MAPP, EVA and EPDM in the specimens increased their impact strength. In the presence of MAPP, higher increase in impact strength of the recycled PP/WF composites was observed due to impact modifiers. Both impact modifiers increased the impact strength of the PP/WF composites but the addition of EVA gave the greatest improvements in impact strength. Although the addition of impact modifiers and MAPP increased the impact strength of composites containing recycled PP, such values were still significantly lower than those of containing virgin PP (not modified with MAPP or impact modifier). The use of impact modifiers decreased the flexural properties of the recycled PP/WF composites