改性硅溶胶-苯丙乳液复合涂层的制备及性能

目的 以硅溶胶、苯丙乳液为主要原材料,制备高性能有机-无机复合涂层,并为其应用提供一定价值的参考.方法 采用KH550、KH560以及KH570等3种硅烷偶联剂依次对硅溶胶进行接枝改性,选用改性效果较好的硅溶胶,制备改性硅溶胶添加量为0％、35％、70％、105％(相对于苯丙乳液的质量百分比)的4种涂层.用傅里叶变换红外光谱仪、马尔文Zeta电位仪以及扫描电子显微镜对硅溶胶的改性效果进行表征,用多功能材料表面性能试验仪等涂层力学测试仪、紫外/可见/近红外分光光度计、扫描电子显微镜分别对4种涂层的力学性能、隔热节能性能及微观形貌进行表征.结果 KH560对碱性硅溶胶的接枝改性效果最优.向苯丙乳液中添加一定量的改性硅溶胶可以显著提升涂层性能.当改性硅溶胶添加量为苯丙乳液质量的70％时,涂层综合性能提升最高,此时涂层太阳光反射比为0.683,近红外反射比为0.624,附着力为3.85 MPa,1000圈磨损后的质量损失率为53％,抗拉强度为5.4 MPa,但断裂伸长率降低较为明显,仅为49.8％.结论 KH560更适合对碱性硅溶胶进行接枝改性.添加KH560改性硅溶胶后,苯丙乳液涂层的力学性能、隔热节能性能得到了显著提升.实际使用时,建议改性硅溶胶添加量为苯丙乳液质量的70％.

Preparation and Properties of Modified Silica Sol Styrene Acrylic Emulsion Composite Coating

This paper aims to prepare high-performance organic-inorganic composite coatings with silica sol and styrene- acrylic emulsion as the main raw materials, and to provide some valuable reference for its application. Three kinds of silane coupling agents, KH550, KH560 and KH570, were used to graft modified silica sol in turn. The silica sol with better modified effect was selected to prepare four kinds of composite coatings with modified silica sol mass of 0%, 35%, 70% and 105% (relative to the mass fraction of styrene acrylic emulsion). The modified effect of silica sol were characterized with Fourier transform infrared spectrometer, Zeta potentiometer and scanning electron microscope (SEM). The heat-insulating and energy-saving properties, mechanical properties and micro morphology of the four coatings were characterized by using ultraviolet/visible/near- infrared spectrophotometer, multi-functional materials surface performance tester and scanning electron microscope (SEM). KH560 has the best graft modification effect on alkaline silica sol. Adding a certain amount of modified silica sol to styrene- acrylic emulsion can significantly improve the performance of the coating. When the additive amount of modified silica sol is 70% of the weight of styrene-acrylic emulsion, the comprehensive performance of the coating is the best, the solar reflection ratio and near-infrared reflection ratio of the coating are 0.683 and 0.624, the adhesion of the coating is 3.85 MPa, the mass loss rate after 1000 rings of wear is 53%, the tensile strength is 5.4 MPa, but the fracture elongation is reduced significantly, only 49.8%. KH560 is more suitable for the grafting modification of alkaline silica sol, and the mechanical properties, heat-insulating and energy-saving properties of styrene-acrylic emulsion coating is significantly improved after adding KH560 modified silica sol. In practical use, it is suggested that the additive amount of modified silica sol is 70% of the mass of styrene- acrylic emulsion.