丙烯酸酯聚氨酯/SiO2纳米复合涂层结构与形态对其耐刮伤性影响研究

以四乙氧基硅烷(TEOS)作为主要前驱体,通过改变溶胶-凝胶工艺参数制得了结构和形态各异的丙烯酸酯聚氨酯/SiO2纳米复合涂层,利用TEM、SAXS等手段表征涂层的结构与形态,由洗刷前后涂层的失光率来表征耐刮伤性,详细探讨了纳米复合涂层耐刮伤性与SiO2相特征、有机无机相作用力及SiO2质量分数之间的关系。研究表明:丙烯酸酯聚氨酯涂层中引入纳米SiO2相后,耐刮伤性明显提高。有机相与SiO2相之间的作用力是影响涂层耐刮伤性的最重要因素,作用力越强,耐刮伤性越好。网络状纳米SiO2与颗粒状纳米SiO2相比,更有利于耐刮伤性的提高,且网络状纳米SiO2质量分数越大,耐刮伤性越佳,但SiO2相的致密度和尺寸对耐刮伤性影响较小。对于颗粒状胶体SiO2,在15~160 nm范围内,粒径对耐刮伤性没有明显影响;随着胶体SiO2粒子的质量分数增加,耐刮伤性先增大后减小。

Study on the Relationship between Structure and Scratch Resistance of Acrylic Based Polyurethane/Silica Nanocomposite Coatings

Acrylic based polyurethane/silica nanocomposite coatings with different structure or morphology were prepared by sol-gel process using tetraethoxysilane(TEOS) as the main precursor.The morphology and structure of the nanocomposite coatings were characterized by transmission electron microscopy(TEM) and small angle X-ray scattering(SAXS) method,while the scratch resistance by the gloss loss of the coatings film after washing.The enhancement of nanosilica(including phase features of SiO_2,interaction and SiO_2 ratio) on the scratch resistance of organic coatings was further discussed in this article.It is found that the scratch resistance of nanocomposite coatings depends rather on the interaction between organic matrix and silica phase than on the character of silica phase,and moreover,the higher the interaction,the better the scratch resistance.It seems that the coatings containing silica network shows better scratch resistance than those containing silica particles.Additionally,the scratch resistance of nanocomposite coatings increases firstly and then decreases with increasing mass fraction of colloidal silica particles but slightly increases with increasing content of silica density or particle size.