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)/beta-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 beta-PP in the composites, whose morphologies and content were governed by TMB-5 due to its high (beta-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 beta-crystals. The special morphological (beta-crystals combined with the reinforcing MMTs is expected to endow PP product with higher strength and toughness. (C) 2016 Elsevier Ltd. All rights reserved.