Treatment of E-glass fibres with acid, base and silanes

Raman spectroscopy, plasma emission spectroscopy, electron spectroscopy for chemical analysis (ESCA), elemental analysis, solution conductivity and pH, were used to characterise the solutions and the acid, base and silane-treated E-glass fibres. Strong acids and bases induced an ion exchange reaction, which caused large quantities of aluminium and calcium to be leached from the E-glass surface. Samples treated with strong bases were found to have large quantities of sodium on the E-glass fibre surface; this came from the sodium hydroxide used to treat the fibres and from the bulk of the fibre. A cyclic isocyanurate silane, which was only partially soluble in water, was detected on the E-glass surface. A cationic amino-functional silane ester with a long organic chain did not completely hydrolyse in an aqueous solution adjusted to pH=4. The solution concentration, which gave the maximum amount deposited, was different for each silane tested.