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Yao Xu Xianyong Sun Dong Wu Yuhan Sun Yongxia Yang Hanzhen Yuan Feng Deng Zhonghua Wu 《Journal of solution chemistry》2007,36(3):327-344
In-situ
29Si liquid-state nuclear magnetic resonance (NMR) was used to investigate the ammonia catalyzed hydrolysis and condensation
of the mixed systems of tetraethoxysilane (TEOS) and dimethyldiethoxysilane (DDS) dissolved in methanol. With ammonia catalysis,
the hydrolysis reaction orders for TEOS and DDS in the mixed systems remained first order, which is similar to that observed
for their corresponding single silane component precursor systems. The hydrolysis rate constant for TEOS in the mixed systems
was larger than that of TEOS in the single silane component precursor systems. Meanwhile, the hydrolysis rate constants of
DDS in the mixed precursor systems were smaller than those of DDS in the single silane component precursor systems. The hydrolysis
and condensation kinetics showed more compatible hydrolysis-condensation relative rates between TEOS and DDS, which remarkably
affected the final microstructure of the resulting silica particles. Small angle X-ray scattering (SAXS) experiments showed
a typical double fractal structure in the particulate networks. 相似文献