含羟基柔性链段纳米二氧化硅的制备及其对高速列车涂层性能的影响研究

摘要

Nano-silica dioxide was modified by organic-inorganic hybrid using a two-step method.Firstly, epoxy resin molecule was grafted onto the surface of nano-silica through the bridging role of isocyanates , then hydroxyl groups which can participate in the cure of crosslink was formed by epoxy group ring opening reaction ,therefore surface grafting hydroxyl-containing soft segments nano-silica was prepared .The influence of mechanical properties and wear resistance of the coating material was studied using different amount of nano-silica.The results show that the organic-inorganic hybrid nano-modified fillers can react chemically with organic resins ,improved dispersion of inorganic nano-silica in the coating and improved the organic/in-organic interface compatibility , thereby the coating toughness and compactness was increased .When the adding amount of modified nano silica was 6%,compared with the coating without modified nano filler ,its abrasion resistance was increased by 24%, the tensile strength was increased by 25%, the elongation at break was increased by 50%,and the saturated water absorption of the coating was reduced by 40%.%采用两步法对纳米二氧化硅进行有机无机杂化改性，首先通过异氰酸酯的桥接作用，在纳米二氧化硅的表面引入环氧树脂分子，再利用环氧基团的碱式开环反应，形成可参与交联固化的羟基，制备了表面接枝含羟基柔性链段的纳米填料，研究了纳米二氧化硅不同用量对涂层材料力学性能与耐磨性能的影响。结果表明，有机无机杂化改性后的纳米二氧化硅能与有机树脂发生化学反应，改善了无机纳米二氧化硅在涂层中的分散性，提高了有机／无机的界面相容性，从而提高了涂层的韧性和致密性。当改性纳米二氧化硅的添加量为6％时，与添加未改性纳米填料的涂层相比，其耐磨性提高了24％，拉伸强度提高了25％，断裂伸长率提高了50％，涂层的饱和吸水率降低了40％。