原料配比对酚醛气凝胶结构和性能的影响OA北大核心CSTPCD

A simple one-pot method for preparing phenolic aerogel(PA)was proposed.Resorcinol and formaldehyde were mixed and added to an alkaline solution,with cetyltrimethylammonium chloride included as a surfactant.PA was prepared by sol-gel and high-temperature aging reactions.The effects of phenolic precursor ratio and pH on the structure and properties of aerogels were investigated.The results show that as formaldehyde content increases,the shrinkage rate of PA decreased,while the density and thermal conductivity increases.When the ratio of phenol to formaldehyde is 1∶4,the aerogel has a typical three-dimensional network structure,with the lowest density of 0.32 g/cm3,good thermal insulation and thermal conductivity of 0.0318 W/(m·K),and the average particle size of PA was 1.059 μm.The higher the pH of the alkaline solution is,the more methylene and methylene ether bonds are,the larger the gel particle size is,and the closer the neck connection is.The PA prepared with ammonia as a catalyst has the smallest shrinkage,the lowest density,and the better thermal insulation performance and thermal stability.