Polyvinylacetate-SiO2 gels obtained in homogeneous media

Polyvinylacetate-SiO2 gels have been obtained by radical polymerization of vinyl acetate (VAc) in the presence of tetraethoxysilane (TEOS). The reacti on system was: VAc:TEOS:EtOH:H2O:S (nonylphenol ethoxylated with 25 moles e thylene oxide) in different ratios. The reaction was performed at 65 degree sC. The initiator of radical polymerization was benzoyl peroxide and a cros slinking agent of sol-gel process bis maleate of diethylene glycol. Traces of acetic acid, maleic acid or acrylic acid catalyze the polymerization of TEOS. The presence of the surfactant (S) ensures the homogeneity of the ini tial system. The conditions of obtaining homogeneous gels have been selecte d. Ternary diagrams containing TEOS:EtOH:H2O or (VAc+TEOS):EtOH:H2O:S were used in order to establish the domains of homogeneous compositions in the s ystems. Refractometric and conductometric measurements have shown that the mentioned systems are microemulsions. X-ray diffraction, surface area measu rements, DTA/TGA method, as weil as IR spectrometry have been used in the c haracterization of the gels obtained.