Interfacial strengths for reinforced dental resins by microbond shear tests

Dental composites normally use a bifunctional silane coupling agent to provide the interfacial phase that holds together the organic polymer matrix with the reinforcing inorganic phase. In this study the interface was either a silane or a silane coupled with a rubber. Microbond tests were used to measure the interfacial bond strength at the fiber/matrix interface. The interface was varied by silanizing the glass fibers (~30 μm diameter, 8 cm length, MoSci) with various concentrations (1%, 5% and 10%) of either 3-methacryloxypropyltrimethoxysilane or glycidoxypropyltrimethoxysilane in acetone (99.8%). Rubber [poly(butadiene/acrylonitrile), amine terminated, molecular weight = 5,500] molecules were also attached to the fiber surface via GPS molecules. The resin was comprised of a 60/40 mixture of bis-phenol-A his(2-hydroxypropyl)-methacrylate and tri(ethylene glycol)dimethacrylate. The same set of samples were soaked in 50:50 (v/v) mixtures of ethanol/distilled water for a period of one month to detect any change in the interfacial properties