Evaluations of PP-g-GMA and PP-g-HEMA as a compatibilizer for polypropylene/clay nanocomposites

Abstract

In this study, we investigated the performances of a hydroxy ethyl methacrylate grafted PP (PP-g-HEMA) and a glycidyl methacrylate grafted PP (PP-g-GMA) as compatibilizers in PP/clay nanocomposites. The compatibilizers were prepared by melt grafting with a radical initiator. Since the PP-g-MA is successfully and widely used in the PP/clay nanocomposites, we also studied three PP-g-MAs containing different amounts of MA and having different molecular weights for a comparison. PP/clay nanocomposites compatibilized by the PP-g-HEMA and the PP-g-GMA show a similar level of the clay interlayer distances with those of the PP-g-MAs. We also investigated the effect of molecular weights of the compatibilizers. In general, the compatibilizer of lower molecular weight was observed to exhibit lower performance as a compatibilizer. It is observed that an increase of polar group content in the modified PP (PP-g-HEMA, PP-g-GMA, and PP-g-MA) always accompanies the molecular weight reduction, which deteriorates the mechanical properties. Thus, we prepared the PP-g-HEMA and PP-g-GMA by incorporation of a styrene comonomer. The compatibilizers (PP-g-HEMA-co-styrene and PP-g-GMA-co-styrene) thus obtained show good performance as a compatibilizer in the PP/clay nanocomposites. We observed that the PP/clay composites containing the PP-g-HEMA-co-styrene and the PP-g-GMA-co-styrene have very well-balanced mechanical properties.