Preparation and High-temperature Resistance of Phenolic Resin/Silicone Rubber Ceramifiable Composites

Ceramifiable BPF/MVQ composites were obtained using methyl vinyl silicone rubber (MVQ) as the matrix, fumed silica as the reinforcing filler, mica as the ceramic filler, and boron phenolic resin (BPF) as the heat-resistant modifier and their vulcanization properties, mechanical properties, thermal properties, morphologies, and ceramic structures were investigated. The results demonstrated that increasing BPF content increased the scorch time (T10), the optimum cure time (T90) and the maximum torque (MH). When the content of BPF was varied from 0 to 40 phr, the tensile strength of the composites increased from 3.33 to 5.61 MPa, the elongation at break decreased from 170% to 85%, and the flexural strength of the pyrolysis composites treated at 1200 °C increased from 4.53 to 11.25 MPa. After the addition of BPF, the thermal gravimetric analysis results indicated that the thermal stability was improved, and SEM revealed that a more continuous and monolithic ceramic structure was formed in the pyrolysis composite with 40 phr BPF. The XRD results indicated that BPF could contribute to forming SiC ceramic structures at 1200 °C; in this way the high-temperature mechanical properties of the BPF/MVQ composites were improved.