Novel polyfunctional silanes for improved hydrolytic stability at the polymer–silica interface

Polyfunctional silanes were designed to promote the formation of a stable multisilane layer on the silica surface. The hydrolytic stability of polyfunctional silanes at the interface between silica and polymeric resin was investigated using conventional tensile testing. The specimens were immersed in boiling water and a decrease was observed in the tensile bonding strength of polymeric resin against the silane-treated silica surface as the immersion time increased. The failure mechanism changes from cohesive failure of the matrix resin to failure of the interface. The time necessary to start the interfacial failure is dependent on the silane concentration in the treating solution and the number of silicone functional groups within the silane molecules. The silane with two silicone functional groups is more stable at the interface between silica and polymeric resin than those which have mono- or trisilicone functional groups.