INFLUENCE OF THE FUSED-SILICA SURFACE DEHYDROXYLATION ON THE ADHESIONOF EPOXYACRYLATE PROTECTIVE COATINGS USED FOR OPTICAL FIBERS

Measurements have been made of the adhesion of liquid and UV-cured epo xyacrylates to a fused silica surface. The fused silica surface was de hydroxylated in the 200-900 degrees C temperature range. Also, the con tact angles of water, diiodomethane and formamide on the fused silica surface were measured. Using the contact angle results, the 'harmonic mean' method and the acid-base interactions approach, the dispersion ( Lifshitz-van der Waals) and electron donor and electron acceptor compo nents of the fused silica surface as well as epoxyacrylate polymer sur face free energy were calculated. It was found that, probably because of the physically adsorbed water, the hydroxylated surface of the fuse d silica is basic and that the adhesion of the epoxyacrylate polymer t o this surface depends on its basicity.