纳米沉淀二氧化硅的硅烷偶联剂原位表面改性

In-situ surface modification of nanometer precipitated amorphous silica by silicane coupling

在沉淀二氧化硅的制备过程中,表面活性剂可以起到提高粒子分散性的作用。通过在沉淀二氧化硅制备过程中加入硅烷偶联剂,研究了硅烷偶联剂原位表面改性对沉淀二氧化硅性质的影响,并通过SEM、FTIR等分析手段对改性机理进行了分析。结果表明,当硅烷偶联剂(牌号为SCA-1613)的用量达到沉淀二氧化硅质量的6.0%时,制备得到的沉淀二氧化硅的物化指标明显改善。制得的样品白度97.1,比表面积223m2/g,吸油率为2.42ml/g,堆积密度为0.23g/ml。对改性前后的样品的SEM和FTIR分析表明,制得的沉淀二氧化硅原级粒度为纳米级,经过原位改性处理后,其团聚现象明显改善。FTIR分析表明,用硅烷偶联剂SCA-1613对沉淀二氧化硅在制备过程中进行表面改性时,改性剂分子吸附在二氧化硅颗粒的表面并与其形成化学键合。

The surfactant plays an important role in the preparation of precipitated amorphous silica on it＇s properties,such as dispersity,BET specific surface area, etc. In this paper, the effect of the in-situ surface modification of nanometer precipitated amorphous silica by silicane coupling on it＇s properties is studied,the mechanism is also been analyzed by SEM and FTIR. The results indicated that the optimum usage of the silicane coupling （designation is SCA-1613） is 6.0% of the mass of precipitated amorphous silica. Under this optimum process condition, whiteness of precipitated amorphous silica is 97.1, BET specific surface area is 223m^2/g, oil-absorb ratio is 2.42ml/g,and bulk density is 0.23g/ml. The SEM photos show that the initial particle size of the precipi- tated amorphous silica is about 50nm, and it＇s dispersity improved obviously after in-situ surface modified by silicane coupling. The FTIR analysis indicates that the silicane coupling molecular is absorbed onto the particle surface by chemical bonding.