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ABSTRACT:The effect of an organically modified montmorillonite (OMMT) on the curing kinetics of a thermoset system based on a bisphenol A epoxy resin and a poly(oxypropylene)diamine curing agent were studied by means of differential scanning calorimetry (DSC) in isothermal and dynamic (constant heating rate) conditions. Montmorillonite and prepared composites were characterized by X-ray diffraction analysis (XRD) and simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). Analysis of DSC data indicated that the presence of the filler has a very small effect on the kinetics of cure. A kinetic model, arising from an autocatalyzed reaction mechanism, was applied to the DSC data. Fairly good agreement between experimental and modeling data was obtained.

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Organic-inorganic hybrid materials based on diglycidyl ether of bisphenol A (DGEBA) and 3-glycidyloxypropyltrimethoxysilane (GLYMO) were prepared, using a poly(oxypropylene) diamine Jeffamine D230 as a curing agent. Materials were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), infrared spectroscopy, swelling in tetrahydrofurane (THF), and Soxhlet extraction in THF. A dependence of the final conversion of epoxy groups and the final degree of organic phase crosslinking on inorganic phase content was found.The inorganic phase presents a steric hindrance to full crosslinking of epoxy groups. It also immobilizes the organic chains and improves the temperature stability of hybrid materials. Products of GLYMO hydrolysis together with unreacted organic molecules lower the glass transition temperature of hybrid materials

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