Preparation and Performance Study of Modified Silica Sol/Phenolic Resin

This study used silica sol, phenol, formaldehyde, etc. as raw materials to prepare silica sol/phenolic resin based on in-situ polymerization. The influence of silica sol content on the viscosity, solid content, and other properties of the composite resin were discussed. The structure and performance of the product were characterized and tested via laser particle size analyzer, infrared spectrum analyzer, thermogravimetric (TG) analyzer, and rheometer. The results show that the viscosity of the composite resin increased with increased silica sol content, and the solid content and the free formaldehyde content exhibited the opposite trend. The laser particle size analysis revealed that when the amount of silica sol was 40%, the particle size distribution of the composite resin was relatively uniform. Fourier transform infrared analysis illustrated a new chemical bond of Si-O-C formed between silica sol and phenolic resin. TG analysis showed that when the amount of modified silica sol was added at a 40% level, the decomposition temperature of composite resin (10% weight loss) increased from 294.8 to 324.4 °C, and the residual amount increased from 55.2% to 60.2%; rheological analysis revealed that when the content of silica sol was 40%, it had better flow properties, creating conditions for the composite resin to penetrate the wood.