室温硫化聚苯乙烯接枝改性硅橡胶的研究

Study on RTV Polystyrene Graft Modified Silicone Rubber

以端羟基聚苯乙烯接枝改性聚二甲基硅氧烷(PS-PDMS)为基胶,加入气相法白炭黑、正硅酸乙酯和二月桂酸二丁基锡,配成脱醇型双组分室温硫化聚苯乙烯接枝改性硅橡胶。研究了PS-PDMS的结构、力学性能和耐高温性能。29Si NMR和1H NMR分析证实,PS-PDMS的结构是以交替排列的Si—O键为主链、侧链为部分甲基被聚苯乙烯取代的接枝共聚物。相比甲基硅橡胶,PS-PDMS硫化胶的力学性能显著提高,耐热性大幅下降。未补强PS-PDMS硫化胶的拉伸强度在2 MPa以上,拉断伸长率在120%以上;气相法白炭黑用量在30份时,PS-PDMS硫化胶的拉伸强度在5 MPa以上;PS-PDMS硫化胶在热质量损失率为5%和20%时的温度分别比甲基硅橡胶低60℃和118℃。

The two-component dealcoholized room temperature vulcanizing （RTV） polystyrene graft mod-ification of silicone rubber was prepared, which was based on hydroxyl terminated polystyrene graft modified polydimethylsiloxane （PS - PDMS） with the addition of the fumed silica, TEOS and dibutyltin dilaurate tin. The structure, mechanical properties and high temperature performance of PS -PDMS were investigated. 29Si NMR and 1H NMR analysis confirmed that the structure of PS -PDMS graft copolymer was alternately arranged in the main chain of Si--O bond and part of the side chain methyl was replaced by polystyrene. Compared to the methyl silicone rubber, the mechanical properties of PS - PDMS were significantly improved, but the heat resistance was significantly deteriorated. The tensile strength of unreinforced PS -PDMS exceeded 2 MPa and the elongation at break exceeded 120%. The amount of silica was more than 30 copies and the tensile strength of PS - PDMS exceeded 5 MPa. At the thermal mass loss rate of 5% and 20% , the corresponding temperatures of PS - PDMS rubber was 60 °C and 118 °C lower than the methyl silicone rubber, respectively.