Thermal Stability and Ablation Properties Study of Aluminum Silicate Ceramic Fiber and Acicular Wollastonite Filled Silicone Rubber Composite

The thermal stability and ablation properties of silicone rubber filled with silica (SiO2), aluminum silicate ceramic fiber (ASF), and acicular wollastonite (AW) were studied in this article. The morphology, composition, and ablation properties of the composite were analyzed after oxyacetylene torch tests. There were three different ceramic layers found in the ablated composite. In the porous ceramic layer, the rubber was decomposed, producing trimers, tetramers, and SiO2. ASF and part of AW still remained and formed a dense layer. The SiO2/SiC filaments in the ceramic layer reduced the permeability of oxygen, improving the ablation properties of the composites. The resultant ceramic layer was the densest, which acted as effective oxygen and heat barriers, and the achieved line ablation rate of the silicone composite were optimum at the proportion of 20 phr/40 phr (ASF/AW). Thermogravimetric analysis (TGA) confirmed that thermal stability of the composites was enhanced by the incorporation of ASF and AW. The formation of the ceramic layer was considered to be responsible for the enhancement of thermal stability and ablation properties. (C) 2013 Wiley Periodicals, Inc.