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

Tris(3-(trimethoxysilyl)propyl)isocyanuratesilane was deposited from anhydr ous methanol. The rate of deposition onto E-glass fibres, of this novel sil ane, was determined by Si-29 NMR spectroscopy. During a 16-h treatment peri od there was no evidence of hydrolysis or condensation of the silane soluti on. The majority of the silane deposition occurred within the first few min utes of the deposition process. Long deposition times resulted in large amo unts 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 ha ve 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 wa s formed. Industrial grade E-glass fibres were shown to have sufficient wat er adsorbed onto the surface to induce hydrolysis and a high degree of cond ensation at the E-glass surface.