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以正硅酸乙酯(TEOS)、水、乙醇(EtOH)为原料,HNO3为催化剂,制备了纳米二氧化硅溶胶.研究了二氧化硅溶胶的红外光谱、反应物的配比和反应温度对二氧化硅溶胶粒径的影响及二氧化硅溶胶在陈化过程中的稳定性.实验结果表明,二氧化硅的缩聚反应在TEOS完全水解前就已开始,TEOS水解不完全;HNO3/TEOS摩尔比对二氧化硅溶胶粒径的影响较小,H2O/TEOS摩尔比对溶胶粒径的影响较大.随着HNO3/TEOS摩尔比、H2O/TEOS摩尔比的增加和反应温度的升高,二氧化硅溶胶的粒径增大;随着EtOH/TEOS摩尔比的增加,二氧化硅溶胶的粒径减小.溶胶在陈化过程中,在体系的粘度发生急剧变化之前,二氧化硅溶胶的粒径和密度变化极小,二氧化硅溶胶是相对稳定的.低温陈化有利于延长溶胶的稳定时间.
Nanosilica sol was prepared by using tetraethoxysilane (TEOS), water and ethanol (EtOH) as raw materials and HNO3 as catalyst.The infrared spectra of silica sol, the ratio of reactants and the reaction temperature The effect of silica sol particle size and the stability of silica sol during the aging process.The experimental results show that the polycondensation reaction of silica has begun before the complete hydrolysis of TEOS and the hydrolysis of TEOS is incomplete.The molar ratio of HNO3 / TEOS The effect of molar ratio of H2O / TEOS on the particle size of sol was larger than that of silica sol, with the molar ratio of HNO3 / TEOS, the molar ratio of H2O / TEOS and the increase of reaction temperature, The particle size of silica sol increases with increasing molar ratio of EtOH to TEOS.The particle size of silica sol decreases with the increase of molar ratio of EtOH to TEOS.The sol of silica sol The particle size and density change is very small, the silica sol is relatively stable. Low temperature aging helps to prolong the sol stability time.