Preparation of poly(methyl methacrylate)/silicon particle composites and the study of the properties improvement

A flame retardants containing phosphorus-silicon, DOPO-VTS, was synthesized and incorporated into polymethyl methacrylate (PMMA) matrix through sol-gel process at different loadings. The results from Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and Differential Scanning Calorimetry (DSC) showed that silicon particle were formed and dispersed well in the PMMA matrix. The addition of DOPO-VTS can not only enhance the flame retardancy of PMMA but also improve the thermal stability of PMMA. When compared to PMMA, the addition of only 15wt% DOPO-VTS results in 28.5% decrease in pHRR. Moreover, 15.0 wt% DOPO-VTS results in 32.0 °C increase in half degradation temperatures (T_0.5). The results of Hot Stage Microscopy (HSM) and FTIR showed that phosphorus-containing compound and the silicon crystal were formed in the char layers during the pyrolysis process, and the char layers can effectively prevent the degradation of PMMA/silicon particle composites. It's believed that this research will stimulate further efforts in silicon particle as the based flame retardants in different polymers for the property reinforcements.