Improvement of the dispersity of micro-nano particles for PP/PVC composites using gas-assisted dispersion in a controlled foaming process

摘要

Polyvinyl chloride (PVC) and nanosilicon dioxide (nano-SiO2) were blended with neat polypropylene (PP) to improve its flame retardancy and cellular foam structure, and the dispersal effects of PVC and nano-SiO2 and the foaming effect of the PP/PVC composites were investigated. PP/PVC samples with different compositions and foaming degrees were first fabricated by conventional injection molding with and without a blowing agent. Tensile testing, differential scanning calorimetry, scanning electron microscopy, limiting oxygen index testing, and vertical burn testing were used to study the mechanical properties, thermal features, microstructures, and flame-retardant properties of the molded samples, and the samples with different degrees of foaming were compared. The results suggest that the foaming process facilitates the dispersion of PVC and nano-SiO2, while the presence of PVC and nano-SiO2 improves the foamability of PP. A method for a gas-assisted dispersion technology to control the foaming process was hence proposed. Considering that the mechanical properties of PP/PVC could be retained with satisfactory flame retardancy and weight loss, convenient processing, and low-cost materials; the technology presented can be directly applied for lightweight engineering and the manufacture of fire-resistant material and can act as a reference for other micro-nano processing involving the dispersion of particles. POLYM. ENG. SCI., 2019. (c) 2019 Society of Plastics Engineers