Structure Characterization and Physical Properties of Exfoliated Polypropylene/Montmorillonite Nanocomposites Synthegized via in situ Polymerization

Polypropylene (PP)/ montmorillonite (MMT) nanocomposites were synthesized by in situ polymerization with Ziegler-Natta/ organically modified MMT compound catalyst prepared by chemical reaction method. The microstructure, thermal stability and the processing stability of PP/MMT nanocomposites were investigated systematically. The results indicate that the exfoliated PP/MMT nanocomposites are produced successfully by in situ polymerization, and the MMT nanolayers are dispersed uniformly in the PP matrix in the nano scale. The average thickness of the MMT layers in PP matrix is less than 10 nm. The increase of MMT content enhances the thermal stability of PP/MT nanoconposite materials. The long-time shearing inevitably leads to the aggregation of some MMT layers, and this aggregation of MMT can be avoided by shortening the shearing time. The α phase is the dominate crystal phase of PP in the in situ synthesized PP/MMT nanocomposites, and the introduction of nano clay can not induce the β phase PP formation. The appearance of β phase PP is related with the annealling temperature.