Crystalline modification and morphology of polypropylene developed under the combined effects of montmorillonite and self-assembly β nucleating agent

In this paper, the crystalline structures of polypropylene (PP)/montmorillonite (MMT)/β-nucleating agent (TMB-5) composites were investigated at the different heating temperatures. The experimental results showed that MMTs had the negligible effect on the formation of β-PP in the composites, whose morphologies and content were governed by TMB-5 due to its high β-nucleating efficiency and the self-assembling character. However, MMTs amplified the flow strength to promote the dissolution of TMB-5 in the PP melts. As a result, more TMB-5 self-assembled at lower temperature compared to the sample without MMTs. Depended on the solubility related to the temperature and MMTs content, various topological aggregations of TMB-5 were formed to direct the epitaxial crystallization of PP into needle-like and dendritic β-crystals. The special morphological β-crystals combined with the reinforcing MMTs is expected to endow PP product with higher strength and toughness.