Novel organic-inorganic hybrids prepared from polybenzoxazine and titania using sol-gel process

Novel organic-inorganic hybrids were prepared from polybenzoxazine and titania using sol-gel process by blending titanium isopropoxide as a precursor for titania with a typical benzoxazine monomer, bis(3-phenyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane (Ba). Deep red brown and transparent hybrid materials were obtained after thermal cure at 200 °C. DSC indicated that, in the presence of titania precursor, the onset and maximum temperature of the exothermic peak due to the ring opening polymerization of Ba decreased by ca. 30 and 70 °C, respectively. Viscoelastic analyses revealed that the glass transition temperatures (T_g) of the polybenzoxazine-titania hybrids shifted to higher temperature than the neat polybenzoxazine. The storage moduli below T_g for the hybrids increased with the increase of the titania content, and the storage moduli were maintained constant up to higher temperature than the neat resin. TGA results confirmed that the thermal stability and char yield of polybenzoxazine increased by hybridization with titania.