气相法二氧化硅对硅橡胶力学性能的影响

Effect of Fumed Silica on the Mechanical Properties of Silicone Rubber

将气相法二氧化硅作为补强填料添加到液体硅橡胶中,研究了气相法二氧化硅对硅橡胶拉伸力学性能和应力松弛的影响。结果表明:随着填料用量从5份增加到15份,采用R202、R974和A200补强的硅橡胶拉伸强度均升高。当填料用量继续增加到20份时,采用R974的硅橡胶拉伸强度继续升高,采用R202和A200的硅橡胶拉伸强度反而降低。当填料用量为15份时,采用R202和A200的硅橡胶拉伸强度均达到最大值,分别为9.54 MPa和8.92 MPa,采用A200、R202和R974补强的硅橡胶拉断伸长率均达到最大值,分别为138.9%、142.0%和128.4%;当填料用量固定为20份时,采用A200、R974、R805、R202和R812S的硅橡胶拉伸强度分别为8.46 MPa、10.09 MPa、9.74 MPa、9.47 MPa和9.28 MPa,拉断伸长率分别为105.81%、125.53%、124.28%、129.59%和172.74%,杨氏模量分别为7.48 MPa、6.65 MPa、6.52 MPa、5.95 MPa和5.59 MPa。采用R974、R812S和A200的硅橡胶,分别拥有最高的拉伸强度、拉断伸长率和杨氏模量;采用A200、R974、R805、R202和R812S的硅橡胶的应力松弛率分别为43.78%、44.43%、41.75%、42.13%和37.33%,交联点密度分别为19.48×10^(-4)mol/mL、22.4×10^(-4)mol/mL、22.0×10^(-4)mol/mL、17.26×10^(-4)mol/mL和13.97×10^(-4)mol/mL。

The effect of fumed silica on the tensile mechanical properties and stress relaxation of silicone rubber was investigated by adding fumed silica as reinforcing filler into the liquid silicone rubber(LSR).The results showed that the tensile strength of silicone rubber reinforced by R202,R974 and A200 increased with the increasing filler from 0 to 15 phr.When the filler continued to increase to 20 phr,the tensile strength of silicone rubber reinforced by R974 kept increasing,while the tensile strength of silicone rubber reinforced by R202 and A200 decreased instead.When the filler was 15 phr,the tensile strength of silicone rubber reinforced by R202 and A200 both reached the maximum of 9.54 MPa and 8.92 MPa,respectively,and the elongation at break of silicone rubber by A200,R202 and R974 reinforcement all reached the maximum of 138.9%,142.0%and 128.4%,respectively.The tensile strengths of the silicone rubber with A200,R974,R805,R202 and R812S were 8.46MPa,10.09MPa,9.74MPa,9.47MPa and 9.28MPa,and the elongation at break were 105.81%,125.53%,124.28%,129.59%and 172.74%,respectively.The Young′s moduli were 7.48 MPa,6.65 MPa,6.52 MPa,5.95 MPa and 5.59 MPa,respectively.The silicone rubber with R974,R812S and A200,had the highest tensile strength,elongation at break and Young′s modulus respectively.The stress relaxation rate of silicone rubber with A200,R974,R805,R202 and R812S was 43.78%,44.43%,41.75%,42.13%and 37.33%respectively,and the crosslink point densities were 19.48×10^(-4)mol/mL,22.4×10^(-4)mol/mL,22.0×10^(-4)mol/mL,17.26×10^(-4)mol/mL and 13.97×10^(-4)mol/mL,respectively.