Effect of Styrene on the Properties of Transparent Flame Retardant Unsaturated Phosphate Copolymer

Abstract
The effect of styrene on unsaturated phosphate ester polymers was investigated. Copolymerization was carried out by adding different proportions of styrene when the unsaturated phosphate was polymerized to obtain an unsaturated phosphate-styrene copolymer. The structure and crosslink density of the copolymer was determined by fourier transform infrared (FTIR) spectra and gel fraction (G) testing. The heat resistance and flame retardancy of the polymer were tested by thermogravimetric (TGA) analysis, limiting oxygen index (LOI) and micro-combustion calorimeter (MCC). The infrared test proved that the styrene was successfully introduced into the polymer system. The gelation test results showed that the introduction of the rigid benzene ring increased the crosslink density of the copolymer. The tensile strength increased from 17.84 MPa to 34.63 MPa, and the impact strength remained stable within a certain range. At the same time, the solid ultraviolet absorption test results showed that the light transmittance of the materials was higher than 90%. The TG and DTG spectra showed that the heat resistance of the polymer was improved, but the residual carbon ratio was reduced from 30.47% to 25.54%. The LOI value decreased from 29.0% to 26.1%, and the UL-94 vertical burn rating was all V-0.