RO Membrane Division, Central Salt & Marine Chemicals Research Institute (Council of Scientific and Industrial Research), G.B. Marg, Bhavnagar 364 002, India.
J Colloid Interface Sci. 2010 Nov 1;351(1):304-14. doi: 10.1016/j.jcis.2010.07.028. Epub 2010 Jul 16.
Silica nanoparticles produced from organically functionalized silicon alkoxide precursors were incorporated into polyamide film to produce a silica-polyamide nanocomposite membrane with enhanced properties. The dispersion of the silica nanoparticles in the nanocomposite membrane was characterized by performing small-angle neutron scattering (SANS) measurements on dilute reactant systems and dilute solution suspensions of the final product. Clear scattering of monodisperse spherical particles of 10-18 A R(g) were observed from dilute solutions of the initial reactant system. These silica nanoparticles initially reacted with diamine monomers of polyamide and subsequently were transformed into polyamide-coated silica nanoparticles; finally nanoparticle aggregates of 27-45 A R(g) were formed. The nanoparticle dispersion of the membrane as the nanosized aggregates is in corroboration with ring- or chain-like assemblies of the nanoparticles dispersed in the bulk polyamide phase as observed by transmission electron microscopy. It is demonstrated that dispersions of silica nanoparticles as the nanosized aggregates in the polyamide phase could be achieved in the nanocomposite membrane with a silica content up to about 2 wt.%. Nanocomposite membranes with higher silica loading approximately 10 wt.% lead to the formation of large aggregates of sizes over 100 A R(g) in addition to the nanosized aggregates.
采用有机官能化硅烷醇盐前体制备的二氧化硅纳米颗粒被掺入聚酰胺薄膜中，以制备具有增强性能的二氧化硅-聚酰胺纳米复合膜。通过对稀释反应物体系和最终产物的稀溶液悬浮液进行小角中子散射（SANS）测量，对纳米复合膜中二氧化硅纳米颗粒的分散情况进行了表征。从初始反应物体系的稀溶液中观察到 10-18A R(g)的单分散球形颗粒的明显散射。这些二氧化硅纳米颗粒最初与聚酰胺的二胺单体反应，随后转化为聚酰胺包覆的二氧化硅纳米颗粒；最终形成 27-45A R(g)的纳米颗粒聚集体。正如透射电子显微镜所观察到的那样，膜中的纳米颗粒分散体作为纳米级聚集体与纳米颗粒在聚酰胺相中的环状或链状组装相吻合。结果表明，在纳米复合材料膜中，当二氧化硅含量高达约 2wt.%时，可以实现纳米级聚集体形式的二氧化硅纳米颗粒分散体。当二氧化硅负载量约为 10wt.%时，除了纳米级聚集体之外，还会形成尺寸超过 100A R(g)的大聚集体。
