Aqueous amino silane modification of E-glass surfaces

The majority of work available in the literature examines the effect of epo xy silane, gamma -aminopropyltrimethoxy silane, and methacrylate silane on E-glass surfaces. As alternatives to the most commonly used siIanes, we inv estigated two novel silanes: gamma -ureidopropyltriethoxy silane and N beta (aminoethyl) gamma -aminotrimethoxy silane and additionally an amino-funct ional polysiloxane. The ureido silane-treated E-glass fibers demonstrated a zeta potential similar to that of the untreated E-glass fibers, which was independent of deposition solution pH over the pH range investigated. A mod erately hydrophobic E-glass surface, which was silane concentration depende nt, was noted as being due to condensed Si-O-Si bonds at the surface. The d iamino silane demonstrated an extremely basic surface at the higher silane concentrations investigated. These outer surface layers were modified by ch anging the pH and the concentration of the deposition solution. The polysil oxane produced an increase in the hydrophobicity of the E-glass fiber, espe cially when deposited from extremely basic solutions. At the higher solutio n concentrations investigated, the silanes and the siloxane was initially d eposited in patches and an outer surface or "skin" was formed over these pa tches, giving the appearance of fully coated fibers. (C) 2001 Academic Pres s.