KH550的水解工艺及其对SiO2表面改性的研究

用电导率在线测量法和红外光谱法研究了硅烷偶联剂3-氨丙基三乙氧基硅烷(KH550)的水解工艺。采用共沸蒸馏和溶剂置换方式置换出湿凝胶中物理吸附水，并用KH550水解液对SiO2湿凝胶进行了改性。通过红外光谱（FT-IR）、邻苯二甲酸二丁酯（DBP）吸油值、粒度分析仪和接触角测定仪等方式对改性效果进行了表征。结果表明，采用KH550对SiO2湿凝胶进行改性后，产品的接触角显著提高，吸油值增大70%以上，孔容为未改性样品的2倍，有机相中的分散性显著提高。同时，对比共沸蒸馏和溶剂置换两种方式，共沸蒸馏得到疏水性更好的超细SiO2，改性后样品的接触角可以达到140°以上。共沸蒸馏过程中，当改性剂KH550用量为超细SiO2绝干粉重的17.5%（质量分数）时，改性效果最好。

Study of the hydrolysis of 3-aminopropyltriethoxysilane (KH550)and the surface modification of silica

Through monitoring the change in conductivity during the hydrolysis of 3-aminopropyltriethoxysilane(KH550) and using FT-IR spectroscopy,the optimum conditions for the hydrolysis of KH550 were investigated.Wet silica gel from which the physisorbed water was removed by azeotropic distillation or rapid solvent replacement was treated with KH550.The products were characterized by Fourier transform infrared spectroscopy(FT-IR),di-n-butylphthalate(DBP) oil absorption,laser particle size analysis and contact angle measurements in order to investigate the effect of modification.The results showed that the contact angle of the modified silica increased,and the DBP absorption value significantly increased by more than 70% compared to the unmodified products.The pore volume was twice that of the unmodified silica.The amount of products in the organic phase also increased significantly.The azeotropic distillation method for wet gel modification afforded more hydrophobic silica than the solvent replacement method,and the contact angle between modified silica and water reached as high as 140°.The optimal conditions for silica modification involved a modifier mass fraction of 17.5% of the weight of silica and the use of azeotropic distillation.