Surface silane coupling agents

The organofunctional portion bonds with the resin in the adhesive or the organic medium, and the silane portion bonds to the inorganic or substrate surface. Silane coupling agents are commonly used between the adhesive and the adherend, between resin matrix and reinforcing fibers in composites, and between resin matrix and mineral fillers in compounds. The resulting interface provides... 

Fig. 20. Schematic representation of the hydrolysis of silane coupling agents and their subsequent interaction with hydroxylated mineral surfaces.

Jones, F.R., Interfacial aspects of glass fibre reinforced plastics. In Jones, F.R. (Ed.), Interfacial Phenomena in Composite Materials. Butterworths, London, 1989, pp. 25-32. Chaudhury, M.K., Gentle, T.M. and Plueddemann, E., Adhesion mechanism of poly(vinyl chloride) to silane primed metal surfaces. J. Adhes. Sci. Technol, 1(1), 29-38 (1987). Gellman, A.J., Naasz, B.M., Schmidt, R.G., Chaudhury, M.K, and Gentle, T.M., Secondary neutral mass spectrometry studies of germanium-silane coupling agent-polymer interphases. J. Adhes. Sci. Technol., 4(7), 597-601 (1990). 

Other aspects of interfacial science and chemistry are examined by Owen and Wool. The former chapter deals with a widely used chemistry to join disparate surfaces, that of silane coupling agents. The latter chapter describes the phenomenon of diffusion at interfaces, which, when it occurs, can yield strong and durable adhesive bonds. Brown s chapter describes the micromechanics at the interface when certain types of diffusive adhesive bonds are broken. The section on surfaces ends with Dillingham s discussion of what can be done to prime surfaces for adhesive bonding. 

The silane coupling agents undergo chemical reaction with the surface of inorganic substances to form an SiOM bond (M Si atom in glass). 

The silane coupling agent is physically adsorbed on the inorganic surface. 

The Si—OH group on the glass surface forms a hydrogen bond with the silanol group derived from the silane coupling agent. 

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