SiO_(2)气凝胶隔热材料制备及隔热耐火性能研究

Preparation of SiO_(2) aerogel thermal insulation material and study on its thermal insulation and fire resistance performance

以正硅酸乙酯为硅源,十六烷基三甲基溴化铵为表面活性剂,采用酸碱两步法制备出了不同表面活性剂CTAB用量的SiO_(2)气凝胶,研究了表面活性剂对气凝胶的微观形貌、晶格结构、隔热性能和耐火性能的影响。研究结果表明:酸碱两步法制备出的SiO2气凝胶是典型的无定型二氧化硅;气凝胶由纳米颗粒相互堆积而成,颗粒尺寸在30~80 nm之间;CTAB的添加减小了SiO_(2)气凝胶的粒子尺寸,骨架发生缩聚,气凝胶的抗压强度得到提高;CTAB含量为0.1 mol的SiO2气凝胶的抗压强度达到了1.216 MPa的最大值。在800℃时,CTAB含量为0.1 mol的SiO_(2)气凝胶的最大残炭量为81.4%,导热系数最低为0.019 W/(m·K),保温性能最佳。CTAB含量为0.1 mol的SiO2气凝胶的垂直燃烧时间最短为8.1 s,LOI值最大为34.8%,垂直燃烧等级达到V1级,气凝胶在燃烧过程中的燃烧速度减弱,阻燃性能得到明显改善。

In this paper,silica aerogel with different amounts of CTAB surfactant were prepared by acid base two⁃step method us⁃ing tetraethyl orthosilicate as silicon source and hexadecyl tri⁃methyl ammonium bromide as surfactant.The effects of surfac⁃tant on the microscopic morphology,lattice structure,thermal in⁃sulation and fire resistance of aerogel were studied.The results show that the SiO_(2) aerogel prepared by the acid base two⁃step method is a typical amorphous silica.The aerogel is formed by the accumulation of nanoparticles,and the particle size is between 30~80 nm.The addition of CTAB reduces the particle size of the SiO_(2) aerogel,and the skeleton is condensed.The compression strength of the aerogel is improved.The compression strength of the SiO2 aerogel with 0.1 mol of CTAB reaches the maximum value of 1.216 MPa.At 800℃,the maximum carbon residue of SiO2 aerogel with 0.1 mol CTAB content is 81.4%,the mini⁃mum thermal conductivity is 0.019 W/(m·K),and the thermal in⁃sulation performance is the best.The shortest vertical combustion time of SiO_(2) aerogel with 0.1 mol CTAB was 8.1 s,the maxi⁃mum LOI value was 34.8%,and the vertical combustion grade reached V1.The combustion rate of aerogel in the combustion process weakened,and the flame retardancy was significantly im⁃proved.