介孔二氧化硅粒子表面改性及其在聚甲基丙烯酸甲酯超临界二氧化碳发泡中的应用

Preparation of Modified Mesoporous Silica Particles and Its Application in Poly(Methyl Methacrylate) Supercritical Carbon Dioxide Foaming

采用水热法合成纤维状的SBA-15型介孔二氧化硅粒子,并对其表面和孔道改性用于聚甲基丙烯酸甲酯(PMMA)的超临界二氧化碳发泡,研究了其在聚合物发泡中的异相成核作用。结果表明,该介孔粒子在PMMA发泡过程能够起到一定的异相成核作用,有助于提高泡孔密度,降低泡孔尺寸。该异相成核作用在发泡温度和压力较低时更加明显。同时介孔粒子的表面特性对成核作用有很大的影响,与KH550改性的粒子相比,含氟硅烷改性的粒子具有较高的成核效率。考察发泡复合材料的力学性能发现其拉伸模量较纯聚合物发泡材料有所提高,但提高幅度与未发泡比相差不大。

Mesoporous silica particles( SBA-15) synthesized by hydrothermal process were modified both at surface and inside,and it was used as heterogeneous nucleating agent for polymethyl methacrylate( PMMA) supercritical carbon dioxide foam,its nucleation effect in polymer foam was investigated. The results show that the mesoporous particles could be used as heterogeneous nucleating agent with improving the cell density,decreasing the average cell diameter especially at low saturation pressure and foaming temperature. Besides,the nucleation efficiency depends partly on surface properties of mesoporous particles. The fluoride silane modified particles have higher nucleation efficiency compared to the silane coupling agent modified ones. Compared with pure PMMA,composite foams containing modified SBA-15 show higher tensile modulus.