控制聚合与沉淀协同作用改善高铁轨道板涂料用水玻璃性能

Improving the Performance of Water Glass Used in the High-speed Rail Slab Coating by the Synergistic Effect of Controlling Polymerization and Precipitation

中文关键词: 水玻璃 聚合 沉淀 力学强度 耐水性

英文关键词: water glass, polymerization, precipitation, mechanical strength, water resistance

中文摘要:

      CaO可能对水玻璃酸碱度、Zeta电位产生影响,引起调控水玻璃中硅氧聚合体的聚合度和形成沉淀的协同作用,有望改善水玻璃的力学强度和耐水性。欲提高环保型高铁轨道板涂料用水玻璃的力学强度和耐水性,本实验拟采用CaO对水玻璃进行改性,并探索改性的相关机理。实验结果表明,CaO改性水玻璃力学强度提高77%,耐水性也明显提高。Zeta电位仪、pH计、X射线衍射仪、傅里叶红外光谱仪及固体核磁共振仪检测结果表明:添加CaO使水玻璃Zeta电位值、pH值均增大；在形成Ca²⁺的协同作用下,导致硅氧聚合体解聚、重组并限制聚合,主要以链状聚合体(Q²)存在。同时Ca²⁺与Q²结合形成耐水性较好、力学强度较高的CaO·xSiO₂·yH₂O(CSH)凝胶,而不是含大量Na⁺、耐水性差的硅氧聚合体。可以推断,CaO可产生控制聚合度和沉淀协同效应改善水玻璃性能,有望应用于高铁轨道板涂料用水玻璃。

英文摘要:

      As CaO may affect the pH and Zeta potential of water glass and cause a synergistic effect of controlling polymerization of polymers in water glass and forming precipitation, it is expected to improve the mechanical strength and water resistance of water glass. To improve the mechanical strength and water resistance of water glass used in high-speed rail slab coating, this paper tries to modify water glass by CaO and to explore the mechanism of such modification. The results showed a higher water resistance and a 77% rise in mechanical strength for water glass modified by CaO. The investigation of Zeta electrometer, pH meter, X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FTIR), and solid-state high-resolution 29Si MAS NMR (NMR) found that the addition of CaO increased pH and zeta potential of water glass; caused silicon oxygen polymer to depolymerize and recombine; and led to silicon oxygen polymer mainly existing in the form of chain polymer (Q²) under the synergistic effects of Ca²⁺. At the same time, Ca²⁺ was combined with Q² to form CaO·xSiO₂·yH₂O (CSH) gel which is of better water resistance and higher mechanical strength, rather than silica oxygen polymer with a large amount of Na⁺ and poor water resistance. It is concluded that the addition of CaO improves mechanical strength and water resistance of water glass by the synergistic effect of controlling polymerization and precipitation, and therefore CaO has good prospects for application in water glass used in high-speed rail slab coating.