Effect of OMMT on microstructure, crystallisation and rheological behaviour of UHMWPE/PP nanocomposites under elongation flow

摘要

Different loadings of organo-montmorillonite (OMMT) were mixed with ultra-high molecular weight polyethylene (UHMWPE)/polypropylene (70/30) composites under elongation flow. Results showed that ideal dispersion of OMMT nanoparticles could be achieved and most OMMTs intercalated and exfoliated effectively. However, the layer spacing of OMMT decreased with the increase in the content of OMMT. UHMWPE was surrounded by the OMMT layers, and its shape evolved from a compatible phase to a sphere. OMMT caused heterogeneous nucleation in the blends, leading to a high crystallisation temperature. Meanwhile, the intercalated and exfoliated OMMTs promoted the motion of polymer chains, and inhibited the crystallisation process of UHMWPE in the composites. The crystallinity of UHMWPE with 5% OMMT markedly decreased from 48.39% to 41.46%. Various rheological analyses confirmed that the complex viscosity of composites and the storage modulus decreased first and then increased with the increase in the content of OMMT. UHMWPE/PP with 5% OMMT exhibited the ideal mobility.