酚醛/SiO_2双体系凝胶网络结构杂化气凝胶的制备与性能  

Preparation of PR/SiO_2 Hybrid Phenolic Aerogel with Bi-component Gel Networks

作　　者：师建军[1] 孔磊[1] 左小彪[1] 刘登瑶 严蛟 冯志海[1] Jian-jun Shi;Lei Kong;Xiao-biao Zuo;Deng-yao Liu;Jiao Yan;Zhi-hai Feng(Aerospace Research Institute of Materials ＆ Processing Technology,Science and Technology on Advanced Functional Composites Technology,Beij＇ing 100076)

机构地区：[1]航天材料及工艺研究所先进功能复合材料技术国防科技重点实验室,北京100076

出　　处：《高分子学报》2018年第10期1307-1314,共8页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号51702076);国家重点基础研究与发展计划项目(973计划;项目号2015CB655200)资助

摘　　要：通过Sol-Gel反应过程控制,调节酚醛树脂(PR)溶液和SiO_2溶胶液的凝胶时间,共凝胶反应制备PR和SiO_2凝胶网络互穿的PR/SiO_2杂化气凝胶.考察了杂化气凝胶表观密度、收缩率、孔结构、微观形貌、热稳定性和力学性能随SiO_2气凝胶含量的基本变化规律.研究结果表明:伴随SiO_2气凝胶含量的增加,PR/SiO_2杂化气凝胶表观密度正比增加;同纯PR有机气凝胶相比,杂化气凝胶孔结构得到明显改善,当[TEOS]=1.50 mol/L时,平均孔径减小了一半,降至0.25μm,比表面积由24.60 m^2/g增至44 m^02/g左右;微观形貌照片显示有机气凝胶网络骨架中的大孔逐渐被SiO_2溶胶粒子填充,变成更细小疏松的孔结构形貌,孔径分布明显变宽,SiO_2气凝胶在PR凝胶骨架中纳米尺度内均匀分散;无机SiO_2气凝胶的引入能有效提高有机气凝胶骨架结构的强度和热稳定性,纳米分散SiO_2溶胶粒子的热阻隔效应抑制了PR有机骨架的热分解速率,当[TEOS]=1.00 mol/L时,杂化气凝胶的T_(max)由539℃提高到602℃,热分解温度区间明显展宽.Hybrid phenolic resin/silica（PR/SiO2） hybrid aerogels with bicomponent and interpenetrating gel networks were prepared through co-gelating reaction by controlling Sol-Gel reaction and tuning gel time of hybrid solution. In this study, variations of the hybrid aerogels properties, including apparent density, linear shrinkage,pore texture, micromorphology, thermal stability and mechanical performance, with their silica aerogel contents were investigated. The results showed that apparent density of PR/SiO2 hybrid aerogels increased proportionally with increasing content of the silica aerogels. Compared to the pure organic phenolic（PR） aerogels, pore texture for PR/SiO2 hybrid aerogels were remarkably affected by the content of silica aerogels introduced by co-gelating reactions of phenolic resin and tetraethoxysilane（TEOS） monomers. Specific surface area of PR/SiO2 hybrid aerogels was improved and the average pore diameter decreased after incorporation of silica aerogels. As studied in the research, when the concentration of TEOS monomers increased to 1.50 mol/L, the average pore diameter of PR/SiO2 hybrid aerogel extremely decreased to 0.25 μm and the specific surface area increased from 24.6 m^2/g for pure PR aerogel to 44 m^2/g. Micromorphology detected by scanning electron microscopy（SEM） displayed that larger pores of hybrid aerogels were gradually filled by silica sol particles with increasing content of silica aerogels, which brought forth much more small openings and wider distribution for the pore diameter.Additionally, the skeleton＇s strength and thermal stability of PR/SiO2 hybrid aerogels were efficiently enhanced after the incorporation of silica aerogels. As the concentration of TEOS monomers was 1 mol/L, the temperature corresponding to the maximum pyrolysis rate（Tmax） was improved from 539 ℃ to 602 ℃, and the thermal decomposition zone of phenolic resin was evidently widened, which suggested that incorporation of silica aerogels effectively inhibited the pyrolysis of phenol

关 键 词：气凝胶 共凝胶 杂化 溶胶-凝胶 孔结构 

分 类 号：TQ427.26[化学工程]