Abstract:

In this paper， the waste plastic mixture was simulated by mechanically mixing polypropylene (PP) and polyethylene (PE)， the PP/PE mixture was blended and at the same time grafted with maleic anhydride (MAH) by reactive extruding， and the wood plastic composites was prepared with the grafted blend， which was used as matrix， and wood fiber. By comparing the infrared spectrogram of the grafted PP/PE blend with that of the unmodified blend， it proved that MAH was grafted onto PP/PE blend. Mechanical testing results showed that the flexural strength and unnotched impact strength of the composites were both significantly enhanced by the blendinggrafting modification of plastic mixture. When MAH dosage was 1%， the flexural strength increased 50.4% and the un-notched impact strength increased 90.8%， and the flexural strength and the un-notched impact strength of the composite prepared from waste plastic increased 40.2% and 53.4% respectively. The micromorphological analysis indicated that with modification the compatibility of PP and PE in the blend system was improved and the interfacial adhesion between wood fiber and PP/PE blend was also enhanced， thus it exhibited the elevation of the mechanical property. This blendinggrafting modification method can be considered as a feasible approach to expand the use of mixing waste plastics in the manufacture of high performance wood plastic composites.

Key words: maleic anhydride(MAH), grafting, PP/PE blend, wood fiber, wood plastic composites