纤维增强气凝胶复合材料高温结构转变及热稳定性研究  

Structural Changes and Thermal Stability of Fiber Reinforced Aerogel Composites

作　　者：赵淑媛[1] 董江龙 孙新杨[1] ZHAO Shu-yuan;DONG Jiang-long;SUN Xin-yang(National Key Laboratory of Science and Technology on Advanced Composites in Special Environments,Harbin Institute of Technology,Harbin 150080,China)

机构地区：[1]哈尔滨工业大学特种环境复合材料技术国家级重点实验室

出　　处：《装备环境工程》2020年第1期58-62,共5页Equipment Environmental Engineering

基　　金：装备预研重点实验室基金(JZ20180035);国防基础科研计划(JZ20180032)~~

摘　　要：目的研究高温受热条件下纳米复合隔热材料的结构转变特征及热稳定性。方法采用扫描电镜、X射线衍射仪、红外光谱仪及热重仪等检测方法。结果纤维增强气凝胶材料从室温到650℃存在连续的质量损失,从室温到放热前,质量损失为1.66%;365℃开始出现放热,温度升至398℃时达到峰值,整个放热过程对应质量损失约为1.3%;从435℃放热结束开始到650℃的质量损失为1.46%。经过400℃热处理后,试样比表面积从268m^2/g增加到437m^2/g;当试样热处理温度达到600℃时,试样的比表面积明显随之降低至198m^2/g。结论SiO2气凝胶复合材料以无定形结构为主,存在少量的二氧化钛晶体。在400℃左右,SiO2气凝胶结构中硅甲基Si-CH3发生氧化,产生明显的放热峰,之后硅羟基Si-OH之间发生缩聚反应,使600℃热处理后气凝胶中Si-O-Si网络骨架强度有所提高。未处理的纤维增强气凝胶材料试样上气凝胶纳米颗粒构成的块体较为良好地包裹在玻璃纤维表面,而经过600℃的高温热处理1 h后,块体气凝胶脱离了光滑的纤维表面,气凝胶纳米粒子发生收缩,致使材料比表面积下降。The paper aims to study the structure transformation characteristics and thermal stability of the heat insulation material-nano composite at high temperature.In this work,inspection methods such as SEM,XRD,FTIR and TGA were adopted.Fiber reinforced aerogel materials from room temperature to 650℃had the quality of the continuous mas loss.From room temperature to the front of the heat,its mass loss was 1.66%;the heat release began at 365℃heat,and reached the peak at 398℃.The quality loss in the whole exothermic process was about 1.3%;the mass loss from 650℃ to 435℃ h was 1.46%.After heat treatment at 400℃,the sample specific surface area increased from 268 m^2/g to 437 m^2/g;when the heat treatment temperature of the sample reached 600℃,the specific surface area of the sample obviously decreased to 198 m^2/g accordingly.The results showed that the silica aerogel composite maintain amorphous structure,and small amount of titanium dioxide exists in crystalline form.At 400℃,Si-CH3 in silica aerogel is oxidized,leading to apparent exothermic peak.Then,polycondensation reaction occurs between Si-OH,increasing the network frame strength of Si-O-Si in aerogel after heat treatment at 600℃.The glass fibers are better covered with silica aerogel agglomerates for the as-received samples.However,after 1 h heat treatment at 600℃,a large proportion of aerogel blocks are fell off from the smooth surface of fibers.The shrinkage of aerogel nanoparticles results in a decrease in the specific surface area of the composite materials.

关 键 词：纤维增强气凝胶复合材料 热稳定性 红外光谱分析 氧化 比表面积 

分 类 号：TJ04[兵器科学与技术—兵器发射理论与技术]