Polypropylene/clay nanocomposites: Effect of compatibilizers on the morphology, mechanical properties and crystallization behaviors

In this study, polypropylene (PP)/organoclay nanocomposites were prepared by melt-compounding PP with three levels of clay loading (3, 5 and 7 wt%), using two different compatibilizers with various contents (5, 10 and 15 wt %), maleic anhydride-grafted polypropylene (PPMA) and hexamethylenediamine-modified maleic anhydride-grafted polypropylene (PPHMA). Effects of structure, mechanical properties and crystallization behaviors of the compatibilizers on the clay dispersion and the amount of clay on the microstructure and mechanical properties of the nanocomposites were investigated. The PPHMA compatibilized system conferred higher mechanical properties than the PPMA compatibilized case. It was found that the PPHMA yielded better clay dispersion and more exfoliated structure compared with the PPMA. Microstructural characterization of the samples was also characterized by transmission electron microscopy. Differential scanning calorimetry results indicate that the addition of compatibilizer increased the crystallization temperature as a result of heterogeneous nucleation effect of clay on PP.