A chemical substance capable of reacting with both the reinforcement and the resin matrix of a composite material. It may also bond inorganic fillers or fibers to organic resins to form or promote a stronger bond at the interface.
May be applied from a solution or the gas phase to the reinforcement, added to the resin, or both. Agent acts as interface between resin and glass fiber (or mineral filler) to form a chemical bridge between the two. Most commonly used are organotrialkoxysilanes, titanates, zirconates and organic acid-chromium chloride coordination complexes. See alsoSILANE COUPLING AGENTS, TITANATE COUPLERS and ADHESION PROMOTER.