SYNTHESIS, CHARACTERIZATION, AND PROPERTIES OF NEW POLYSTYRENE-SIO2 HYBRID SOL-GEL MATERIALS

A new family of organic-inorganic hybrid materials has been prepared b y incorporating polystyrene structure units covalently into the SiO2 g lass network via the sol-gel approach. The polymer precursors were syn thesized by free-radical copolymerization of styrene with 3-(trimethox ysilyl)propyl methacrylate (MSMA) at various feeds. These copolymers w ere then hydrolyzed and co-condensed with tetraethyl orthosilicate in tetrahydrofuran at room temperature to afford monolithic polystyrene-S iO2 hybrid sol-gel materials having SiO2 contents of 15 to 84% by weig ht. The hybrid materials derived from the copolymers with MSMA content s greater than 22 mol % have excellent optical transparency. In these transparent hybrid materials, the polymer chains should be uniformly d istributed in and covalently bonded to the amorphous SiO2 matrices. Th e bulk properties of these materials including density, refractive ind ex, and hardness were found to be related to their molecular compositi ons and can be tailored by varying the polymer contents.