POLYMER COMPOSITES OBTAINED BY POLYMERIZATION OF MICROEMULSIONS FORMED WITH INORGANIC AND ORGANIC MONOMERS

Phase behavior studies bf microemulsions containing the monomers methy l methacrylate (MMA), acrylic acid (AA), and tetraethoxysilane (TEOS), the cross-linking agent ethylene glycol dimethacrylate (EGDMA), and w ater (W), stabilized by the surfactant cetyltrimethylammonium bromide (CTAB), were carried out. An analagous surfactant-free system was also studied and compared with the surfactant-based system. Macroscopicall y single-phase, transparent microemulsions were formed over a consider able portion of the composition domain for the surfactant-based system . The effects of hydrochloric acid (HCl) and base (NH4OH) on the gel t imes were examined. Selected compositions in the surfactant-based syst em were chosen to examine the effect of the water to TEOS ratio (R) on the thermal stability and pore morphology of the polymer composite fo rmed from the hydrolysis and condensation reactions of TEOS and the po lymerization of organic-monomer-containing microemulsions. The polymer composites thus obtained exhibit high thermal stability and uniform p ore morphology. Thermal stability and pore morphology studies were car ried out using differential scanning calorimetry and scanning electron microscopy, respectively. The effect of nitrogen purging on gel time and the effect of EGDMA (a cross-linking agent) on pore morphology are also discussed.