Journal of Photochemistry, 16 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (1981) 279 - 288 279 zyxwvu PHOTOACOUSTIC STUDY OF SILICA-SILANE COUPLING REAGENT INTERACTIONS M. E. ABU-ZEID and G. S. MAHMOUD Physics Department, Kuwait University, P.O. Box 5969 (Kuwait) A. A. ANANE, A. F. HALASA and A. A. MOBASHER Material Science and Application Department, Kuwait Institute for Scientific Reseurch {Kuwait) (Received March 20,198l) Summary Photoacoustic spectroscopy is an effective technique for studying filler- coupling reagent interactions. The use of coupling agents with inorganic fillers necessitates a thorough understanding of the binding activity that takes place. The binding of vinyltrietboxysilane to the hydroxyl groups on a silica surface was identified. Whereas the visible part of the photoacoustic spectra revealed that strong binding took place, the near IR characterized the surface binding groups. 1 _ Introduction The use of mineral fillers in a resin matrix has been the subject of increased research activity. In addition to reducing materials cost [ 1, 21, these fillers also reduce shrinkage, thus improving water resistance and weathering properties [3 - 5]_ To allow better dispersion of the inorganic filler in the organic polymer, coupling agents such as silanes and titanates [6] are being used. These reagents are bifunctional and thus have the ability to react through their silane group with the surface of the filler and with a second group, such as a vinyl group, which reacts with the polymer. For binding with the filler surface, only one hydrolyzable group is required per silane molecule [7 3. However, most of the commercially available silanes have three hydrolyzable groups. Though this should make their application to fillers easier, there is a possibility of polyhydroxysilanes condensing with each other. In this work it is intended to establish whether chemical binding of vinyltriethoxysilane (VTES) to the silica surface or self- condensation polymerization is prevalent. This problem has been dealt with extensively before, using IR transmission and reflection spectroscopy [ 8 - lo] , Raman spectroscopy [ 11 J and inelastic tunnelling spectroscopy [ 121. In 0047-2670/81/0000-0000/$02.50 0 Elsevier Sequoia/Printed in Switzerland