Synthesis and characterization of abrasion resistant coating materials prepared by the sol-gel approach: I. Coatings based on functionalized aliphatic diols and diethylenetriamine

The synthesis of inorganic organic hybrid materials has been undertaken and used as abrasion resistant coatings for polymeric substrates by the sol-gel method. The organic components are diethylenetriamine (DETA), glycerol, and a series of aliphatic diols which are functionalized by 3-isocyanatopropyltriethoxysilane. The inorganic components are tetramethoxysilane (TMOS), aluminum tri-see-butoxide, titaniumsec-butoxide and zirconiumn-propoxide. Solutions of these materials are spin coated onto bisphenol-A polycarbonate sheet and thermally cured to obtain a transparent coating of a few microns in thickness. Following the curing, the abrasion resistance is measured and compared with a control having no coating. It was found that the abrasion resistance of inorganic organic hybrid coatings in the neat form or containing additional silicon, titanium, zirconium, and aluminum alkoxides can be very effective to improve abrasion resistance. The adhesion tests show that the adhesion between coating and substrate can be greatly improved by treating the polymeric substrate surface with an oxygen plasma or a primer solution of isopropanol containing 3-aminopropyltriethoxysilane. Other experiments, such as the abrasion resistance tests following conditioning in a hot-wet condition (boiling water treatment), microhardness tests. UV absorption behavior, and the observation of abraded surfaces, were also undertaken in order to evaluate these coating materials.