Preparation And Characterization Of Calcium Sulfate Whisker/Clay Aerogel Composites

The clay aerogel features low density, large specific surface area and high porosity, thus featuring great application prospect. Furthermore, the production process of the clay aerogel and related composite material is simple and environmental friendly. However, the weak mechanical property of clay aerogel greatly limits its scope of usage. Therefore, this paper expands the scope of usage of the clay aerogel by enhancing its mechanical properties.Aiming at enhancing the mechanical property of the clay aerogel, a series of calcium sulfate whisker/clay aerogel composites have been made by freeze-drying technique, with using calcium sulfate whisker as reinforcement, At the same time to observe the effects of enhanced body on its performance. It's shown that the addition of calcium sulfate whisker enables the composite of clay aerogel to forming block easily, thus to obviously improve its mechanical property in comparing with pure clay aerogel. When the volume of addition of calcium sulfate whisker is1wt%, 2wt% and 3wt%, the mechanical property of clay aerogel are 0.85 MPa ? 1.378 MPa ? 3.63 MPa respectively. At the same time, the heat conductivity coefficient of calcium sulfate whisker/clay aerogel composite is lower than the pure clay aerogel. When the volume of addition is 4wt%, the conductivity coefficient of the calcium sulfate whisker/clay aerogel composite is 0.0452 W·m-1·K-1.This paper also studies the influence of different adhesives on the reinforcement effect of calcium sulfate whisker. A series of calcium sulfate whisker/clay aerogel composites have been made with using different materials varying in volume, such as polyvinyl alcohol, pectin, casein, as the adhesives between the clay and the calcium sulfate whisker. It's shown that the properties of mechanics, thermal conduction and stability of the calcium sulfate whisker/clay aerogel composites with different materials as adhesives are different from each other.The performance of the calcium sulfate whisker/clay aerogel composite with pectin as adhesive could be optimized by adding cross-linking agent. It's shown that the addition of cross-linking agent can enable calcium sulfate whisker/clay aerogel composite with better mechanical property. The enhancement effect is: Al2(SO4)3·18H2O> CaCl2>NaCl. When the crosslinking agent isAl2(SO4)3·18H2O, the calcium sulphate whisker/clay aerogel composite modulus of compression can achieve 13.6MPa, the modulus can be up to 123.6.