氯端基聚硅氧烷偶联剂的合成及其在增强硅橡胶中的应用

New Coupling Agentα-Chlorine-ω-Trichlorine Polysiloxane Group-Ended with Chlorine for Silicone Rubber Reinforcing

以八甲基环四硅氧烷和SiCl_4为原料,通过阳离子开环聚合合成了端基为氯的α-氯-ω-三氯线型聚硅氧烷(PTCSO)偶联剂,采用傅里叶变换红外光谱、硅核磁共振、端基滴定法对其结构进行了表征。用质量分数6%(相对于气相白炭黑的质量)的PTCSO偶联剂改性气相白炭黑,并填充到硅橡胶中,考察了增强硅橡胶的力学性能。实验结果表明,在硅橡胶中填充40份(质量份数,基于100份的硅橡胶)改性气相白炭黑的增强硅橡胶的拉伸强度为9.9 MPa,较填充40份未改性气相白炭黑的硅橡胶的拉伸强度(7.2 MPa)提高了37.5%;当改性气相白炭黑用量增至60份时,增强硅橡胶的拉伸强度达到最大值(11.2 MPa),改性气相白炭黑的增强作用明显。透射电子显微镜表征结果显示,当改性气相白炭黑的用量为60份时,改性气相白炭黑仍能均匀分散在硅橡胶中,且颗粒团聚倾向小。

A macromolecular coupling agent of α-Chlorine-ω-trichlorine polysiloxane group-ended with chlorine （PTCSO） was synthesized by cationic ring-opening polymerization of octamethyl- cyclotetrasiloxane with silicon tetrachloride. FTIR and ^29Si NMR were used to characterize their structures and group-ended titration was employed to determine number-average relative molecular mass of the coupling agent. Fume silica modified by 6% PTCSO（based on mass of fume silica） was filled to reinforce silicone rubber. When 100 portion silicone rubber was filled with 40 portion （ mass portion, based on silicone rubber） modified fume silica, the tensile strength was 9.9 MPa which was improved by 37.5% in comparing with silicone rubber reinforced by 40 portion unmodified fume silica. Tensile strength of silicone rubber filled with 60 portion modified fume silica reached a desired reinforcing effect of maximum 11.2 MPa. TEM images of the sample suggested that modified fume silica dispersed evenly in silicone rubber matrix with slight aggregation even if the filling amount went up to 60 portion.