The effect of epoxy and tetramethyl thiuram disulfide on melt-grafting of maleic anhydride onto polypropylene by reactive extrusion

In this report, melt grafting of maleic anhydride (MAH) and epoxy resin onto polypropylene (PP) by peroxide-initiated reactive extrusion has been investigated. As evidenced by Fourier transform infrared spectroscopy, both MAH and epoxy resin were successfully grafted onto PP through the reactions of MAH with PP and epoxy resin with MAH. It was found that tetramethyl thiuram disulfide could promote the grafting of MAH and inhibit the degradation of PP, as revealed by chemical titration and melt flow experiments, through prolonging the lifetime of the macroradical; meanwhile, epoxy resin could reduce the sublimation of MAH and the maximum grafting degree of MAH. Furthermore, the introduction of grafted products was found to enhance the mechanical properties of PP/glass fiber composites, and this influence was very significant at high grafting degrees with a high content of epoxy resin, which could be interpreted in terms of improved compatibility and adhesion at the interface. (C) 2016 Wiley Periodicals, Inc.