Properties of phenol formaldehyde resin modified with silane coupling agent (KH550)

In the present work, the organic silane coupling agent KH550 (γ-aminopropyltriethoxysilane) was added in the preparation of phenol formaldehyde (PF) resin by direct copolymerization. Such an addition modified the thermosetting low molecular weight PF resin, blocking the phenolic hydroxyl and improving its electrical insulation performance in humid environments. The volume resistance and bonding strength of the resins were tested before and after soaking in hot water. The improvement of the properties was studied in terms of resin composition and curing behavior. A common PF resin and a commercial insulation PF resin were used for the comparison. The results showed that KH550 was grafted onto the PF resin, effectively blocking the polar phenolic hydroxyl group, reducing the water absorption and increasing the volume resistance of the cured PF resin. The preparation process was simple and the prepared resin was water-soluble. The low molecular weight PF resin modified with 5% in mass of KH550 (based on the mass of phenol) exhibited better curing properties and superior volume resistance and bonding strength in humid environments.