Effects Of Graphene Oxide On The Degradation And Grafting Of Maleic Anhydride Grafted Polypropylene

Maleic anhydride?MAH?grafted polypropylene?PP?was widely used in industry.However,there are two important issues in its preparation by melt grafting strategy.On the one hand,PP degrades seriously during the melt grafting due to?-scission of tertiary hydrocarbon radicals.On the other hand,the grafting ratio of MAH onto PP is usually low.In this work,graphene oxide?GO?and styrene?St?were introduced into MAH melting grafted PP for the purpose of decreasing degradation degree and increasing grafting ratio respectively.The effects of GO on the grafting and degradation of PP have been investigated systematically.The main research contents and conclusions are as follows:?1?Interactions between GO and MAH:The interactions between GO and MAH was characterized by FT-IR spectra,X-ray diffraction and thermalgravimetric analysis.The characterization results showed that GO and MAH have hydrogen bonding interactions and/or the esterification between the hydroxyl groups of GO and the carbonyl groups of MAH.Moreover,MAH was inserted into the layer or absorbed on the surface of GO.Meanwhile,the thermal stability of MAH component in GO/MAH compound decreased,which was attributed to the interactions between GO and MAH.?2?Effects of GO on the melt grafting of MAH onto PP:The PP chain scission was significantly inhibited and the grafting ratio of MAH decreased markedly with the incorporation of GO into the MAH grafting PP system.It is considered that GO/MAH compound was able to quench the tertiary hydrocarbon radicals?PP₃·?rapidly,thus preventing the chain scission of MAH grafted PP?PP-g-MAH?significantly;meanwhile,the grafting ratio of MAH decreased markedly due to the decreasing of PP₃·concentration.?3?Effects of GO on the melt grafting of St-MAH onto PP:After the introduction of GO into the melt grafting of St-MAH onto PP,the chain scission of PP-g-MAH was significantly inhibited and the grafting ratio of MAH was maintained at a high level.We consider that the GO/MAH compound was able to quench the tertiary hydrocarbon radicals?PP₃·?rapidly,thus preventing the chain scission of PP-g-MAH.Meanwhile,PP₃-St·was formed by grafting St onto PP,and PP₃·radicals were stabilized and activated by the rich electron cloud of the double carbon bonds and aromatic conjugated structure in St,thus preventing the chain scission of PP₃-St·radicals and quenching of PP₃-St·by GO/MAH compound.Subsequently,MAH was grafted with St in the form of alternating copolymerization onto PP₃-St·radicals,which resulted in a high MAH grafting ratio level.?4?Compatibilization effects of PP-g-MAH on PP/GF composites:PP-g-MAH prepared in our work was used to compatibilize PP/GF composites by means of injection molding.It was found that the PP-g-MAH prepared in this work showed better compatibilization effects than commercial PP-g-MAH.Meanwhile,PP-g-MAH with low molecular weight and high grafting ratio was found to be able to compatibilize PP/GF composites effectively.