Hydrophobic properties of new epoxy-silica hybrids

New products to be employed as coatings for construction materials have been synthesized. Room temperature blending of poly(bisphenolA-co-epichlorohydrin), glycidyl endcapped (DGEBA) and 3-amino-ropyl-methyldiethoxysilane (AMTS), as well as of DGEBA, (3-glycidyloxypropyl)trimethoxysilane (GLYTS) and AMTS, in CHCl3, employing different stoichiometric ratios, leads to transparent and crack free solids. The extent of epoxy cleavage during the hardening reaction and the hydrolysis of the Si(OR), groups have been followed by C-13 NMR spectroscopy in solution; the solids have been characterized by means of Raman, FTIR, and TG-DTA studies. The hydrophobic properties of the resulting solids have been investigated by contact angle measurements on coated glass slides, and have been tailored by adding to the above mixtures two fluorine-containing comonomers, namely glycidyl-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononyl ether (GLY16F) and 3,3,3-trifluoropropyl-trimethoxysilane (TFP-MS). Preliminary tests to evaluate the efficacy of the above products, as construction materials coatings, have been carried out by means of mercury intrusion porosimetry and water absorption by the wicking method. (C) 2008 Wiley Periodicals, Inc.