DTQ硅树脂的制备及对RTV-2硅橡胶性能的影响

Preparation of DTQ Silicone Resin and its Effect on the Properties of RTV-2 Silicone Rubber

采用二甲基二甲氧基硅烷、甲基三甲氧基硅烷、正硅酸乙酯经水解缩聚制得DTQ硅树脂,将其添加到双组分室温硫化(RTV-2)硅橡胶中。研究了DTQ硅树脂用量、T链节含量、Q链节含量、烷氧基水解程度对RTV-2硅橡胶性能的影响。结果表明,DTQ硅树脂含有较多的活性羟基,加入RTV-2硅橡胶后能在催化剂作用下优先与α,ω-二羟基聚二甲基硅氧烷反应,提高聚二甲基硅氧烷的分子量并增加支链结构,进而提升RTV-2硅橡胶的断裂伸长率;制备DTQ硅树脂的较佳条件为二甲基二甲氧基硅烷、甲基三甲氧基硅烷、正硅酸乙酯物质的量之比为1∶0.2∶0.2,水添加量为体系中烷氧基物质的量的50%;DTQ硅树脂的较佳用量为6%,此时制得的RTV-2硅橡胶断裂伸长率为338%,拉伸强度保持在0.97 MPa,拉断时间保持30 min以上。

DTQ silicone resin was prepared by hydrolysis polycondensation of dimethyl dimethoxy siliane,methyl trimethoxysilane,tetraethyl orthosilicate,and then it was added to two-component room temperature vulcanized(RTV-2)silicone rubber.The effects of DTQ silicone resin dosage,T chain segment content,Q chain segment content,and alkoxy hydrolysis degree on the performance of RTV-2 silicone rubber were studied.The results show that DTQ silicone resin exhibited a large amount of active hydroxyl groups.After adding RTV-2 silicone rubber,it could react with 107 silicone rubber under the catalyst,increase the molecular weight of polydimethylsiloxane and increase the branched chain structure,thereby improving the elongation at break of RTV-2 silicone rubber.The condition for preparing DTQ silicone resin was when the ratio of dimethyl dimethoxy silane,methyl trimethoxysilane and tetraethyl orthosilicate was at 1∶0.2∶0.2,and the water added was at 50%of the alkoxy substance in the system;The optimal DTQ silicone resin amount was 6%,and the elongation at break of RTV-2 silicone rubber was 338%,thus the RTV-2 silicone rubber possessed a tensile strength of 0.97 MPa,and a breaking time of more than 30 minutes.