EPOXY-MODIFIED AND DIOL-MODIFIED SILICA - OPTIMIZATION OF SURFACE BONDING REACTION

The 3-glycidyloxypropyltrimethoxysilane-silica bonding reaction was in vestigated. The carbon and bonded epoxide content after the bonding re action and the vicinal diol and total hydroxy group content after the subsequent opening reaction were determined. The highest yield pf bond ed epoxide groups was obtained in water at pH 8.5 and ambient temperat ure. The corresponding diol phase behaves well in the size-exclusion c hromatography of poly(ethylene glycol)s in water. Neither the silane b onding reaction nor the subsequent epoxide opening reaction give rise to diol structures only; formation of glycol ethers cannot be avoided. The bonding reaction in toluene gives mostly surface-bonded glycol-et her structures.