白炭黑对陶瓷化硅橡胶瓷化性能的影响

Effect of Silica on Ceramifying Properties of Silicone Rubber-based Ceramizable Composites

研究了白炭黑种类及其用量对硅橡胶瓷化形成的陶瓷体的三点弯曲强度、压缩强度、烧蚀质量损失率和烧蚀线性收缩率的影响,采用扫描电镜(SEM)观察陶瓷体断面的微观形貌。结果表明,相比加入沉淀法白炭黑的硅橡胶,加入气相法白炭黑的硅橡胶形成的陶瓷体的三点弯曲强度和压缩强度更高,烧蚀线性收缩率更大,陶瓷体断面更致密,硅橡胶的瓷化效果更较好;随着气相法白炭黑用量增大,陶瓷体的三点弯曲强度和压缩强度逐渐增大,烧蚀质量损失率和线性收缩率减小,陶瓷体表面鼓包减少,断面致密性提高;当气相法白炭黑用量为40份时,陶瓷体的最大弯曲强度和最大压缩强度分别为14.1 MPa和6.0 MPa,最小烧蚀质量损失率和最小线性收缩率分别为37.6%和2.8%。

The effects of variety and contents of silica on the properties of ceramizable silicone rubber,such as three point flexural strength,compressive strength,weight loss percentage and percent of linear shrinkage,were investigated,whose fracture surface was analyzed by SEM. It is shown that the ceramizable silicone rubber added with fumed silica has higher flexural strength and compressive strength,higher percentage of linear shrinkage,more compact fracture surface and better ceramifying effects than that added with precipitated silica. The three point flexural strength and compressive strength of the ceramics increases,the percentage of weight loss and linear shrinkage decreases,and its ceramic surface shows a few bubbles and the inner compactness with the increasing silica. With the addition of 40 phr fumed silica,the ceramics show the maximum flexural strength and the maximum compressive strength with the values of 14. 1 MPa and 6. 0 MPa,respectively,as well as the minimum weight loss percentage and the minimum percent of linear shrinkage of37. 6% and 2. 8%,respectively.