The reactivities of nanoscale colloidal silica toward epoxy compounds and their applications

• Main Authors: Chih-Yuan Hsu, 許智淵
• Other Authors: Ying-Ling Liu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/51826282208383746294

碩士 === 中原大學 === 化學工程研究所 === 92 === Abstract Chemical functionalization on nano-scaled silica particles was performed through the reaction between the silanol group of silica and the oxirane ring of epoxy compounds. The occurrence of the surface functionalization and the chemical structures of the resulting products were characterized with FTIR and 1H NMR. This approach provides another method to organically functionalize nano-scaled silica particles and can be applied to the preparation of organic-inorganic nanocomposites. Epoxy-silica nanocomposites were obtained from directly curing diglycidyl ether of bisphenol-A with nanoscale colloidal silica. The epoxy-silica nanocomposites showed good transparency and miscibility observed with SEM. The thermal stability of the epoxy resins was improved with the incorporation of the colloidal silica. However, the nanoscale colloidal silica did not show effect on char formation and flame retardance. Poly (methyl methacrylate)-silica hybrid materials were prepared from copolymerization of methyl methacrylate with silica nanoparticles surface-functionalized with allyl glycidyl ether. This preparation method provided a new approach without employing alkoxysilane coupling agents and involving sol-gel reactions. Hybrid materials having high silica loading over 70 wt﹪were obtained good transparency and homogeneous dispersion of the silica particles in the polymer. Glass transition temperatures were not observed from hybrid materials by DSC measurement to indicate the hybrid material had good thermal and dimensional stability. The hybrid materials also showed high hardness over “9H” grade with a pencil test. Thermal gravimetric analysis revealed the thermal degradation mechanisms of the PMMA polymers were not significantly altered by the added inorganic silica particles. To inhibit the swelling of chitosan membranes in aqueous alcohol solutions, which leads to lowered water permselectivity during separation, organic-inorganic hybrid membranes composed of chitosan and modified nanoscale colloidal silica were prepared. These novel hybrid membranes have high separation factor and good permeation rate for the pervaporation of 90 wt﹪ethanol aqueous solutions at 70℃. The results showed that adding the colloidal silica improved the permselectivity and affirmed the permeation rate of chitosan hybrid membranes.