Poly(methylphenylsiloxane)-modified resorcinol-terephthalaldehyde phenolic xerogel monoliths

Fabrication of polymer porous xerogel with environment-friendly and simplified procedure is important target for reducing pollution and production cost. In this research, a sustainable method to prepare thermal insulator of polysiloxane-phenolic composite porous xerogel monoliths was studied by replacing hazardous and volatile formaldehyde with terephthalaldehyde in phenolic component and applying facile ambient drying process. The homogeneous dispersion of poly(methylphenylsiloxane) and resorcinol-terephthalaldehyde in xerogels was achieved by adjusting catalysis condition, water-ethanol content and prepolymer component. Typical poly(methylphenylsiloxane) and resorcinol-terephthalaldehyde composite xerogel monolith had density of about 0.3 g/cm 3 , 65.4% mass retention rate at 800 °C under nitrogen atmosphere, and thermal conductivity 0.063 W/(m·K) at room temperature. According to Thermogravity analysis coupled with Fourier Transform Infrared Spectra (TG-FTIR), pyrolysis mechanism and structure transformation were revealed. The typical pyrolyzed derivatives at 600 °C and 800 °C well preserved the integrated structure, low density, thermal insulation property, and thermal oxidation stability.