Effect of filler treatments on the crystallization, mechanical properties, morphologies and heat resistance of Polypropylene/phlogopite composites

Phlogopite was treated with pimelic acid (PA) and PA/Ca(OH)(2) in ethanol solution by ball milling, separately. The particle size of the phlogopite decreased after the wet grinding, and -nucleating agents (magnesium pimelate and calcium pimelate) were produced after the treatments. Polypropylene/phlogopite composites were prepared in a twin screw extruder. The melt and crystallization behaviors, mechanical properties, morphologies, heat resistance, and processing properties of the composites were characterized. Many crystals appear and the spherulitic sizes decrease obviously with the addition of the treated phlogopites. When compared with the untreated phlogopite composites, the tensile strength, flexural strength, and Izod notched impact strength of the treated phlogopite composites improve significantly. The mechanical properties of PA/Ca(OH)(2)-treated phlogopite composites are the best. The preferential orientation of the phlogopite flakes, numerous small spherulites and enhanced interfacial adhesion contribute to the improved toughness of the composites. The heat deflection temperatures, shrinkages and densities of the treated phlogopite composites are greater than those of the untreated phlogopite composites. POLYM. COMPOS., 40:E795-E810, 2019. (c) 2018 Society of Plastics Engineers