Characterization and performance analysis of silane and tannin modified phenolic foam

To address safety hazards such as gas leakage and spontaneous combustion of coal seams in coal mining, silane-modified tannin phenolic foam (T-KPF), a three-dimensional flexible crosslinked network, was prepared by modifying phenolic resin with tannic acid and the silane coupling agent KH-560. Surprisingly, the formation of Si-O-C bonds with the resin endows the foam with outstanding properties during the hydrolyzation of KH-560. The optimal properties were achieved with a 6% KH-560 loading, showing a compressive strength of 134 kPa, a powdering rate of 3.2%, a water absorption of 25.6%, a limiting oxygen index of 43.2%, and a uniform pore structure. This modification strategy overcomes the brittleness and high-temperature decomposition limitations during the traditional phenolic foam preparation procedure, providing a high-performance material for coal mine safety sealing and promoting the sustainable application of natural polymer materials.