The Study Of Preparation, Characterization And Properties Of Polypropylene/montmorillonite Nanocomposites

The intercalation modification of montmorillonite(MMT) was investigated thoroughly in this paper. A variety of intercalation agents were employed to increase the interlayer spacing of MMT. Amine salt of silane coupling agent was adopted as a kind of intercalation agent, which can react with the hydroxyl radical of MMT surface to improve the interfacial compatibility. Alkyl amine which can react with anhydride radical of compatibilizer was also used as a kind of intercalation agent. Besides, a new kind of co-intercalation organophilic montmorillonite was developed using both titanate coupling agent and alkyl amine salt, which had a larger interlayer spacing than the ordinarily organophilic MMT modified with only one intercalation agent. Polypropylene/MMT nanocomposites were prepared by melt-intercalation using maleic anhydride grafted polypropylene(MA-PP) as compatibilizer. Meanwhile, the nonisothermal crystallization kinetics of the nanocomposites was investigated by means of differential scanning calorimeltry(DSC). The results showed that both the crystallization temperature and rate of PP were increased by the introduction of PP-MA and MMT, which functioned as nucleation centers during the nonisothermal crystallization process of PP. The mechanical properties of PP/MMT nanocomposites with and without MA-PP compatibilizer was also investigated in this paper. The results showed that for the nanocomposites in the absence of MA-PP, MMT was dispersed as common filler and didn't form the intercalation structure in PP matrix, which resulted in decreased mechanical properties. As for the nanocomposites in the presence of MA-PP, the TEM image showed PP penetrated into the interlayer of MMT which was dispersed uniformly in the matrix. With the increasing of MMT content, the yield strength of the composites remained unchanged and its fracture strength increased. And its impact strength reached the peak value with 1~2% content of MMT.