Preparation, Characterization, and Thermal Stability of Novel PMMA/Expandable Graphite Halogen-Free Flame Retardant Composites

摘要

In this investigation, expandable graphite was function-alized using a coupling agent to produce covalent bonds between the organic and inorganic phases, enhancing the thermal stability of the composites .The modified expandable graphite had an -OEt function group that reacted with methyl methacrylate-co-3-(tri-methoxysilyl)propyl methacrylate. Fourier transform-infrared spectrometry and X-ray photoelectron spectra were adopted to characterize the grafting reaction between vinyltriethoxysilane and expandable graphite. It is affirmed that VTES has reacted with expandable graphite. The results of thermogravimetric analysis and thermogravimetric difference (TGA) reveal that func-tionalized expandable graphite can improve the thermal stability of composites. Scanning electron microscope was utilized to observe the morphology of the composites, and the behavior of expansion was discussed after the materials were burned. These results of X-ray photoelectron spectra for char confirm that expandable graphite improves the degree of accumulation of char and that of the antioxidation of the composites.