The Effect of the <math>H2 0</math> /Teos Ratio on the Structure of Gels Derived by the Acid Catalysed Hydrolysis of Tetraethoxysilane.

Nota de FísicaPublicado

The Effect of the $<math>H_2 0</math>$ /Teos Ratio on the Structure of Gels Derived by the Acid Catalysed Hydrolysis of Tetraethoxysilane.

I. Strawbridge; A. Craievich; P.F. James

1985

Autores: I. Strawbridge; A. Craievich; P.F. James
Tipo: Nota de Física
Status: Publicado
Data de publicação: 1985
Descrição: Silica gels were produced by the acid catalysed hydrolysis of tetraethoxysilane (TEOS) using <math>H_20\,\!</math> / TEOS ratios from 2 to 50. After heat treatment the structure of the gels was studied using nitrogen adsorption, small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and bulk density measurements. All the gels possessed microporosity in the region of 30 <math> \AA </math> or less. For <math>H_20\,\!</math> /TEOS = 25 and 50 the matrix density was found to be uniform, but for gels from solutions with <math>H_20\,\!</math> /TEOS = 2, 4 and 10, density fluctuations in the matrix were detected from a Porod analysis of the SAXS data. These results indicate that in high water content solutions, rearrangement of the polymeric chains leads to small densified particles, but for lower water content solutions, gelation results from the entanglement of linear chains leaving free volume on a molecular scale between the chains.
Ano: 1985
Número: CBPF-NF-030/85
Vínculo com tese: Não
Vínculo com bolsa: Não