SiO_2超微粉体改性及其分散性研究

探讨了硅烷偶联剂(KH570)的水解工艺,对SiO_2超微粉体进行了接枝改性;利用红外光谱(IR)、热失重(TG)等手段对改性粉体进行了表征;采用机械搅拌、超声波方法对粉体进行了分散实验,通过沉淀法和分光光度计法对分散效果进行了分析。结果表明:KH570最佳水解条件如下:KH570:水:乙醇体积比为1:1:4,pH值为4～6,水解时间约为30 min;IR和TG分析显示,KH570与SiO_2粉体发生了表面接枝反应;18 h后的沉降高度、透光率的数据证明,改性后粉体分散性明显改善,机械搅拌效果优于超声波分散。

Study on modification and dispersion of ultrafine SiO2 powder

The hydrolysis process of silane coupling agent(KH570) was discussed.The graft modification of ultrafine SiO_2 powder was conducted.The modified powder was characterized by infared spectroscopy(IR) and thermal gravimetric analysis (TG).The dispersion effect was analyzed by sedimentation method and spectrophotometric measurement.The results showed that the optimal process conditions for KH570 was decided as followed:KH570:water:alcohol volume ratio of 1:1:4,pH value of 4-6 and hydrolysis time 30 min.The IR and TG results showed that the surface grafting reaction occured between KH570 and SiO_2.The sedimentation height and transmittance data in 18 h showed that the dispersion of the powder was considerably improved after modification and the mechanical stirring was superior to the ultrasonic dispersion.