engleski

Preparation of Epoxy-Based Organic-Inorganic Hybrids by Sol-Gel Process

Epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) and poly(oxypropylene) diamine Jeffamine D230 was modified by adding modified silicon alkoxide, 3-glycidyloxypropyltrimethoxysilane (GLYMO), in the reaction mixture. Inorganic phase inside the organic matrix is formed by sol-gel process, which includes hydrolysis and condensation of alkoxy groups of GLYMO. Thus obtained hybrid organic-inorganic materials were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), infrared spectroscopy, swelling in tetrahydrofuran (THF) and Soxhlet extraction in THF. It was found that both the final conversion of epoxy groups and the final degree of cross-linking in the material depend on content of inorganic phase in the hybrid material. Epoxy groups of GLYMO were found to react only with primary amine. The inorganic phase presents a steric hindrance to full cross-linking of epoxy groups. The organic chains are also immobilised by the inorganic phase, and its presence improves the temperature stability of hybrid materials. Products of GLYMO hydrolysis combined with lesser degree of cross-linking in organic matrix lower the glass transition temperature of hybrid materials.

nanocomposites; silica; sol-gel process; structure; thermosets

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