Research On The Synthesis And Performance Of MAPP Used As Coupling Agent Of Wood-polypropylene Composites

Maleic anhydride grafted polypropylene (MAPP) was synthesized by reactive extrusion of polypropylene(PP) and maleic anhydride (MAH) with dicumyl peroxide (DCP) as initiator, and more attention was paid to investigate the relationship between the composition and structure of MAPP and its performance as the coupling agent of wood plastic composite.The prepared MAPP was purified by solvent extraction and analyzed by FTIR spectroscopy. There was a absorption peak at 1700 1900cm^-1, which was the characteristic absorption peak of C=O group in MAPP. This showed that maleic anhydride had grafted on the molecule of polypropylene. The grafting ratio of MAH on PP was calculated from FTIR results. The effect of the dosage of MAH and DCP on the grafting ratio of MAPP was as follows: If there was enough maleic anhydride, by increasing the amount of DCP, the grafting ratio of MAPP became bigger because of increase of the concentration of PP reactive radicals. While in case the amount of DCP was too big, the concentration of PP radicals was too high and this would cause cross linking of PP, resulting in the decrease of grafting ratio. Excessive maleic anhydride might cause the capture of the free radical of DCP decomposition and restrained the grafting reaction. From the experiment a high graft ratio (1.76%) was achieved by the reagents proportioning of 100/5/0.5 respectively for PP, MAH and DCP.After preparing wood-flour-polypropylene composite, carried through mechanical performance test and dynamic mechanical analysis. When the grafting ratio of MAPP was about 1%, the tensile strength and flexural strength of the wood-flour-polypropylene composite was the best. Tensile strength and flexural strength of wood-flour-polypropylene composite were increasing with the amount of MAPP increasing, until the amount of MAPP reached to 5 percent. With increasing the amount of MAPP, the loss tangent (tanδ) peak value of composite decreased, the glass transition temperature increased.Preparing different mesh wood flour/polypropylene composite, carried through mechanical performance test and dynamic mechanical analysis. With wood mesh increasing, the impact strength of composite increased. The flexural strength and tensile strength slightly decreased. With wood flour mesh increasing, the storage of composite was not obviously downtrend, while the loss modulus increased, the damp performance of composite increased, and the grass transition temperature increased, heat-resistant performance of the composite improved.