Surface functionalization of ZrO2 nanocrystallites for the integration into acrylate nanocomposite films.

Surface functionalized zirconia nanoparticles were prepared by covalent grafting of a methacrylate functionalized silane (methacryloxypropyltrimethoxysilane, MPTS) onto the surface of the zirconia nanoparticles (tetragonal and mixed monoclinic/tetragonal phase) obtained by hydrothermal treatment of zirconyl chloride octahydrate. The particles are 70 nm aggregates of nanometric primary grains (4-12 nm) with inter particle porosity. BET measurements show that the specific surface area of the particles after activation at 100 degrees C is between 85 and 204 m2/g depending on the mineralizer used (Sr2+, Ca2+, Mg2+). IR-measurements show that the surface of the particles can be covered with functional groups bound through a variable number of ZrOSi bonds to render them organocompatible. The surface modified particles were dispersed in monomer solution (butanediol monoacrylate, BDMA) and polymerized to form films by adding a cross linking agent (trimethylolpropane triacrylate, Laromer TMPTA) and an UV initiator (2,4,6-trimethylbenzoyldiphenylphosphine oxide, Lucirin TPO). The received films were characterized with thermogravimetry and UV-vis spectroscopy.