疏水SiO_(2)气凝胶颗粒的制备与性质研究

Preparation and properties of hydrophobic SiO_(2)aerogel particles

以廉价的无机材料Na_(2)SiO_(3)(硅酸钠)为硅源,经溶胶-凝胶与冷冻干燥过程制得SA(二氧化硅气凝胶)颗粒,探究硅源质量分数对SA颗粒性质的影响,优化制备条件。为克服SA颗粒的亲水性,引入TMCS(三甲基氯硅烷),使材料获得良好的疏水性(水接触角为121°),极低的密度(0.063 g/cm^(3)),出色的导热系数[0.0398 W/(m·K)]和热稳定性。提出一种通用和简单的方法制备SA颗粒并进行改性,在建筑隔热保温领域有较大的应用潜力。

Using inexpensive inorganic Na_(2)SiO_(3)(sodium silicate)as silicon source,the SA(silica source to produce silica aerogels)particles were prepared by sol-gel and freeze-drying processes.The effect of silica source mass fraction on the properties of SA particles was investigated.The preparation conditions were optimized.To overcome the hydrophilicity of SA particles,TMCS(trimethylchlorosilane)was introduced to give the material good hydrophobicity(water contact angle is 121°).The obtained material has very low density(0.063 g/cm^(3))and outstanding thermal conductivity[0.0398 W/(m·K)].A general and simple method is proposed to prepare and modify SA particles,which shows a large potential in the field of building thermal insulation.