热膨胀硅橡胶性能对比及热物改性研究

Comparison of properties and thermal modification of thermal expansion silicone rubber

为了获得性能优异且适应性广的复合材料软模成型用热膨胀硅橡胶,研究三种热膨胀硅橡胶的流动、耐热、热膨胀及弹性性能,通过分级-复合-分散的方式将两种二氧化硅粒子添加分散至热膨胀硅橡胶,并对硅橡胶的流动、耐热及热膨胀性进行研究。结果发现,硅橡胶Ⅰ固化交联反应黏度增加慢、交联固化时间长,耐热、热膨胀性最佳,适合应用于复合材料软模成型工艺。硅橡胶Ⅰ最多填充2 phr纳米二氧化硅、60 phr微米二氧化硅,微米二氧化硅的改性效果优于纳米二氧化硅,当微米二氧化硅用量为60 phr时,硅橡胶室温至200℃平均线膨胀系数为210.0×10^(-6)℃^(-1),比未添加填料的硅橡胶降低约22%,硅橡胶室温至200℃平均弹性模量为4.7 MPa,比未添加填料的硅橡胶提高约96%。实验结果满足硅橡胶的热物改性需求,扩大了软模成型工艺热膨胀硅橡胶的应用范围。

In order to obtain thermal expansion silicone rubber for composite soft molding with excellent performance and wide adaptability,the flow,heat resistance,thermal expansion and elastic properties of three kinds of thermal expansion silicone rubber were tested.Two kinds of silica particles were added and dispersed into the thermal expansion silicone rubber by the way of grading composite dispersion.Then the flow,heat resistance and thermal expansion of silicone rubber were studied.The results show that silicone rubberⅠhave the advantages of slow increase of curing reaction viscosity,long curing time,best heat resistance and thermal expansion properties,and is suitable for soft molding of composite materials.The silicone rubberⅠis filled with a maximum of 2 phr of nano-silica and 60 phr of micron silica which has a better modification effect than that of nano-silica.When the amount of micron silica is 60 phr,the average linear expansion coefficient of silicone rubber is 210.0×10^(-6)℃^(-1)from room temperature to 200℃,which is about 22%lower than that of silicone rubber without added filler.The average elastic modulus of silicone rubber is 4.7 MPa from room temperature to 200℃,which is about 96%higher than that of silicone rubber without filler.The results meet the demand for thermal material modification of silicone rubber and expands the application scope of thermal expansion silicone rubber for soft mold molding process.