Preparation and Properties of Thermoplastic Expandable Microspheres With P(VDC-AN-MMA) Shell by Suspension Polymerization

摘要

Thermoplastic expandable microspheres (TEMs) having core/shell structure were prepared via suspension polymerization with vinylidene chloride (VDC), acrylonitrile (AN), and methyl methacrylate (MMA) as monomers and i-butane as blowing agent. TEMs were about 20 mu m in diameter and had a hollow core containing i-butane. The influence of the monomer feed ratio and blowing agent content was researched. When the monomers composition of 58.4wt% VDC, 28wt% AN, 13.6wt% MMA, and 32wt% i-butane in oil phase, suspension polymerization could yield TEMs having good expansion properties. The maximum expansion volume was 25 times of original volume at about 111-120 degrees C, the blowing agent content in microspheres was about 21.5wt%. The T-m.e, T-o.e, and T-o.s. of the TEMs increased with the VDC content in the polymerizable monomers decreasing.