Deposition of amine functional silanes onto E-glass fibres, an NMR study

Abstract

Tris(3-(trimethoxysilyl)propyl)isocyanuratesilane was deposited from anhydrous methanol. The rate of deposition onto E-glass fibres, of this novel silane, was determined by 29Si NMR spectroscopy. During a 16-h treatment period there was no evidence of hydrolysis or condensation of the silane solution. The majority of the silane deposition occurred within the first few minutes of the deposition process. Long deposition times resulted in large amounts of deposited silanes, which were easily dislodged when the fibres were removed from the solution and dried. Given a coherent, highly ordered film it was calculated that 1400 layers of isocyanuratesilane were deposited in a 2% by weight silane solution. It is accepted, however, that silanes are unlikely to deposit as a coherent layer, and condensation will disrupt any previously ordered layers. Solid state NMR indicated that isocyanuratesilane and a ureidosilane may have been bonded to E-glass fibres at a small number of surface SiO sites and that from these locations a highly crosslinked siloxane polymer network was formed. Industrial grade E-glass fibres were shown to have sufficient water adsorbed onto the surface to induce hydrolysis and a high degree of condensation at the E-glass surface.