Effect of impact modifier and coupling agent on impact strength of wood flour/recycled polypropylene composites

摘要

In contrast to flexural and tensile properties, the results of all research have so far shownrnlower impact strength of composites made from recycled plastics and lignocellulosic materials inrncomparison to composites made from virgin plastics. In this research, the improvement of impactrnstrength of wood flour/fiber-recycled polypropylene (PP) composites was considered. The PPrn(virgin and recycled polypropylene at 2nd( R2P)and 5th ( R5P) recycling stages) and wood flourrnwere compounded at 50% by weight wood flour loading in a counter-rotating twin-screwrnextruder in the presence of MAPP and two types of impact modifiers (ethylene vinyl acetatern(EVA) and ethylene/propylene/diene terpolymer (EPDM)), to produce wood flour-PPrncomposites. The results have shown that the composites containing recycled PP exhibitrnsignificantly lower impact strength than those containing virgin PP (VP). The addition of MAPP,rnEVA and EPDM increased the impact strength of the recycled PP/WF composites. When thernimpact modifiers were used in the presence of MAPP, higher increase was observed in impactrnstrength of the recycled PP/WF composites. Although the addition of impact modifiers andrnMAPP increased the impact strength of composites containing RPP, the impact strengths of theserncomposites were still significantly lower than that of composites containing VP (not modifiedrnwith MAPP or impact modifier). The use of impact modifiers decreased the flexural properties ofrnthe recycled PP/WF composites.