Investigations on coatings generated from silica–zirconia hybrid sols synthesized through hydrolytic/non-hydrolytic wet chemical routes on PMMA substrates

Organic–inorganic silica–zirconia hybrid sols were synthesized by a wet chemical process using an organically modified silane (methacryloxypropyltrimethoxysilane) and zirconium-n-propoxide. One sol was synthesized through a hydrolytic route using isopropanol as the solvent, whereas another was synthesized through a non-hydrolytic route using tetrahydrofuran as the solvent. These sols were independently dip coated on flat polymethylmethacrylate (PMMA) substrates. The coated substrates were subjected to ultraviolet curing followed by thermal curing at 80 °C for 6 h. The cured coatings were characterized and tested for their optical (UV–vis transmittance, haze), mechanical (abrasion resistance) and weather resistance properties according to ASTM standard testing methods. The FTIR spectra were also acquired and analyzed to study the bonding characteristics under the two synthesis conditions. The properties of the coatings obtained from the hybrid sols synthesized through hydrolytic/non-hydrolytic routes were compared.