【作者】 李楠；

【导师】 姜波；

【作者基本信息】 哈尔滨工业大学 ， 材料与化工（专业学位）， 2022， 硕士

【摘要】 硅橡胶防护涂层通过高温下的物相转变等吸热效应阻止热量传导,保证内部仪器的正常运转,具有防护效率高和加工便捷的优点。界面粘接性能在涂层实际服役过程中起到关键性作用,涂层常用硅橡胶基体的表面活性低,粘接性差,使得涂层和基材之间的粘接强度不符合实际需求。粘接促进剂具有便捷的施工工艺和卓越的促进效果,以其处理基材表面可有效改善界面粘接性能。因此,开发一种结构性能优异的粘接促进剂,研究其对硅橡胶涂层性能的影响,可大幅提高涂层的粘接性能,拓宽热防护涂层的应用领域。本论文针对硅橡胶粘接性差的科学问题,根据硅橡胶和基材表面特性对粘接促进剂的组分进行设计与调控,系统地研究了粘接促进剂的固化工艺和粘接性能。粘接促进剂可将硅橡胶和铝合金的粘接强度提高264.71%。制备的胶接件具有良好的耐高温性能,在150℃老化后仍可保持0.83 MPa的粘接强度,确保其在服役过程中有良好的抗冲刷能力。进一步研究粘接促进剂的适用性和储存稳定性,结果表明其对金属基材和端羟基硅橡胶的粘接有良好的促进作用,储存60 d后仍可确保牢固粘接。从固化反应过程和基材表面润湿性两个方面深入探究粘接促进剂的界面作用机理,粘接促进剂水解产生Si—OH,以底漆膜的形式牢固地附着在铝合金表面,将其表面能提高了85.40%,改善了铝合金表面润湿性,使硅橡胶更易于铺展,从而提高硅橡胶和铝合金之间的粘接强度。硅橡胶自身的低强度和弱极性限制了其与基材之间粘接性能的进一步提升,利用伯胺和环氧基的开环反应制备硅烷化环氧树脂,将其和端羟基聚二甲基二苯基硅氧烷共固化,制备环氧改性硅橡胶基体。引入的羟基、环氧基和醚键等具有高反应活性和极性的基团可以提高硅橡胶与基材的粘接性能。硅烷化环氧树脂的引入完善了交联网络,当添加量为20 phr时,基体与铝合金的粘接强度提高了111.11%。研究了粘接促进剂对环氧改性硅橡胶涂层性能的影响,实验结果表明涂层和铝合金之间的粘接强度提高了80.90%,并且具有良好的耐高温和耐烧蚀性能。本论文制备的粘接促进剂对硅橡胶涂层与铝合金基材的粘接有优异的促进效果,拓展了硅橡胶的应用领域,对于开发高粘接性热防护涂层具有重要意义。更多还原

【Abstract】 The thermal protective silicone rubber coating prevents heat conduction by endothermic effects such as phase transition at high temperature,which ensures the normal operation of internal instruments,and has the advantages of high protection efficiency and convenient processing.The interface adhesion performance plays a key role in the actual service process of the coating.The weak surface activity of silicone rubber leads to poor bonding strength between coating and substrate which fail to meet the actual requirements.Adhesion promoter with facile construction process and excellent promotion effect could effectively improve the adhesion performance.Therefore,developing an adhesion promoter with the above mentioned properties and studying its influence on the properties of silicone rubber coating could greatly improve the adhesion properties of coating and broaden the application fields of thermal protective coatings.Aiming at weak adhesion of silicone rubber,this work designed the composition of adhesion promoters according to the surface properties of silicone rubber and substrates,and systematically studied the curing process and adhesion properties.The adhesion promoter improved the bonding strength between silicone rubber and aluminum alloy by 264.71%.The good thermal resistance allowed it to maintain the bonding strength of 0.83 MPa after aging at 150 °C,ensured good erosion resistance during service.The applicability and storage stability of the adhesion promoter were further studied,and the results showed that primer had a good promoting effect on the adhesion between metal substrates and hydroxyl-terminated silicone rubber.And it could ensure firm adhesion after 60 days of storage.The reaction mechanism of the adhesion promoter was explored from the curing reaction process and the wettability of the substrate surface.The adhesion promoter was hydrolyzed to generate Si—OH,which was firmly attached to the surface of the aluminum alloy in the form of primer film.The surface energy of the substrate was increased by 85.40%,which improved the wettability of the aluminum alloy surface and made the silicone rubber easier to spread,thereby improving the bonding strength between the silicone rubber and the aluminum alloy.The low strength and weak polarity of silicone rubber posed challenges on the enhancement of adhesion between silicone rubber and substrate.The silane modified epoxy resin was prepared by ring opening reaction between primary amine and epoxy group,and then co-cured with hydroxyl-terminated polydimethyldiphenylsiloxane to prepare epoxy-modified silicone rubber matrix.The introduced hydroxyl,epoxy and ether bond groups with high reactivity and polarity could improve the adhesive properties between silicone rubber and substrates.The introduction of silane modified epoxy resin improved the cross-linking network.When the addition amount was 20 phr,the bonding strength between the matrix and the aluminum alloy increased by 111.11%.The coating treated with adhesion promoter increased the bonding strength between silicone coating and aluminum alloy by 80.90%.The coating also exhibited good high temperature resistance and ablation resistance.In this paper,the prepared adhesion promoter greatly promoted the adhesion between silicone rubber coating and aluminum alloy substrate,which expanded the application field of silicone rubber and was of great significance for the development of high-adhesion thermal protective coatings.更多还原