AFt@SiO_2核/壳结构的制备及其性能研究

Preparation and Performance of AFt@SiO_2 Core/Shell Structure

钙矾石(AFt,3CaO·Al_2O_3·3CaSO_4·32H_2O)因其结构中含有大量结晶水而具备了用于制造阻燃材料的潜质。以Al2(SO4)3·18H2O和Ca(OH)2为原料,在200℃条件下通过水热反应进行钙矾石的合成实验,研究了反应物浓度,反应时间,pH值对反应产物的影响,并使用改进的St9ber法在钙矾石晶体表面包覆SiO_2壳层,制备AFt/SiO_2核/壳结构。采用XRD、SEM、FT-IR、TG等方法对产物表征测试。结果表明:通过水热法可以快速合成出高纯度,结晶性好的钙矾石晶体,pH=10是钙矾石晶体生长的适宜条件;SiO_2壳层的包覆能控制AFt的脱水速率,也会降低AFt的含水率。

Ettringite（ AFt,3Ca O·Al2O3·3Ca SO4·32H2O） possessed the potential to be used as flame retardant material because of its plenty crystal water. Al2（ SO4）3·18H2O and Ca（ OH）2was used as raw materials and reacted in a hydrothermal condition of 200 ℃ to implement the experiment of synthesising ettringite. The influences of the concentration of raw material,reaction time and pH value on the product were researched. An improved St9 ber method was used to coat a shell of SiO2 on the surface of ettringite crystal in order to prepare AFt/SiO2core/shell structure. The products were characterized by XRD,SEM,FT-IR,and TG. The results show that hydrothermal method can be used to synthesize ettringite crystal with high purity and excellent crystallinity,pH = 10 is a suitable circumstance of the growth of ettringite crystals. The coating of SiO2 can control the dehydration speed of AFt and decrease the moisture content of AFt.