IN-SITU POLYMERIZATION OF TITANIUM ALKOXIDES IN POLYVINYLACETATE

A new hybrid organic-inorganic material is obtained by the in situ pol ymerization of titanium isopropoxide in polyvinylacetate. The hydrolys is and condensation reactions of the alkoxide are carried out in a tet rahydrofuran solution, via a controlled sol-gel process which yields m acroscopically homogeneous and transparent films. Small angle X-ray sc attering allows for the determination of a composite structure of the films, i.e., a dispersion of 'titanium oxide' particles in the organic polymer matrix. The crosslinked nature of the resulting compounds is shown. Thus strong interactions exist between the polymer and the inor ganic phase, avoiding a macroscopic phase separation. Those interactio ns are proved to be covalent links; it is therefore possible to crossl ink chemically the thermoplastic polymer with the inorganic phase. Dyn amical mechanical spectroscopy reveals the existence of two relaxation s which might account for an interphase between polyvinylacetate and t itanium oxide clusters.