engleski

Properties of the epoxy/silica hybrids prepared by sol-gel process

Organic-inorganic hybrids obtained by sol-gel process have found widespread attention and application in recent years. Several reviews on their synthesis and properties are available. In this work three organic-inorganic hybrid materials based on thermoset epoxy resin, diglycidyl ether of bisphenole A (DGEBA), and an epoxy functionalised silane, 3-glycidyloxypropyltrimethoxysilane (GLYMO), were prepared by the sol-gel process. Poly(oxypropylene) diamine (JEFFAMINE&reg ; ; D 230) was used as a curing agent. Curing was effected at room temperature making use of air humidity for hydrolysing GLYMO. The materials were postcured at 120°C. The (post)curing kinetics of investigated systems were studied by differential scanning calorimetry (DSC). Properties of the prepared materials were studied by means of thermogravimetric analysis (TGA), infrared spectroscopy (IR) and swelling in tetrahydrofurane (THF). A lower total heat of reaction developed during simultaneous polymerisation of DGEBA/GLYMO systems in dynamic DSC tests was found, compared to the total heats developed during pure DGEBA and GLYMO polymerisation. The influence of the DGEBA/GLYMO blend composition on the final conversion, on the degree of crosslinking as well as on the equilibrium degree of swelling was discussed. Results could indicate that sterical hindrances between the hybrid system components make complete crosslinking impossible.

organic-inorgani hybrids; sol-gel; structure; properties

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