水玻璃的贮存和组分的变化

WATER GLASS 'S STORAGE AND ITS CHANGEMENT OF COMPONENT

本文采用三甲基硅烷化-气相色谱法(简称TMS-GC法),利用有机单活性基团((CH_3)_3Si-)与水玻璃中硅酸离子活性端基(≡Si-OH或≡Si-O^-)反应,使之变成惰性端基(≡Si-O-Si(CH_3)_3)以防止硅酸的聚合,从而测得了水玻璃中硅酸物种的真实分布.实验结果表明:水玻璃是单硅、二硅、三硅等硅酸的混合物,在放置过程中,其组分发生改变,单硅的含量降低,聚硅的含量升降不一,其变化情况与水玻璃的模数(SiO_2/Na_2O的摩尔数之比)以及浓度(以SiO_2％计)等因素密切相关.

In the paper, the real distribution of silicic acid species in water glass has been determined by use of Trimethylsilyl-Gas-Chromatography. In this process, the ionic active terminal group of silicic acid(≡ Si-OH, or ≡ Si-O-) in water glass reacted with organic monoactive group((CH3)3Si-) to transform into inert terminal group (≡Si-O-Si(CH3)3) in order to prevent silicic acid from polymerizing. The results showed that water glass was the mixture of monosilicic acid, disilicic acid, trisilicic acid and the other polysilicic acids. Its species and structure would change during the storage time, the content of monosilicic acid decreased, but that of the other polysilicic acid changed indefinitely, there was the closely relationship between its situation of changement and SiO2 / Na2O mole ratio and concentration of water glass.