Reaction Mechanism And Low Temperature Resistance Of K₂O·nSiO₂-based Material For Fireproof Glass

Improving the security level of fireproof glass and using fireproof glass on a large-scale is a requirement of modern building’s regulations.Thus,researching on high-performance fireproof glass materials and industrial production process of fireproof glass are necessary on both theoretical significance and practical needs.In this study,different stages of compound K₂O?nSiO₂ based fireproof materials from high solid SiO₂ dispersed solution were studied.It is mainly divided into three aspects:1)The influence of solid content and temperature change on the stability of the initial nano-SiO₂ dispersed solution.2)The reaction kinetics of K₂O?nSiO₂ based fireproof materials formed by adding KOH into the initial nano-SiO₂ dispersed solution were studied.3)In view of the poor low temperature performance of K₂O?nSiO₂ based fireproof glass;the reasons were investigated and find how to improve the low temperature performance of fireproof glass.The backscattering spectra of high solid content nano-SiO₂ particles dispersed solutions show that,the stability of Nano-SiO₂ particles dispersed solution was positively proportional to the solid content of SiO₂,and the higher solid content of SiO₂,the better stability.The dispersed solution’s stability which made with 50%solid content is optimal.The higher solid content of SiO₂ in dispersed solution,the more silicon hydroxyl group and more network structure formed in the system,the higher volume of viscosity will has better stability.The settlement rate equations of nano-SiO₂ particle dispersed solution with solid content of 42%and 50%were obtained respectively,and the settling process of Nano-SiO₂ particle dispersed solution was concluded to be a thermal acceleration process.The transmittance spectra of the fireproof solution reveals that the curing reaction of K₂O?nSiO₂ based solution prepared with high solid content nano-SiO₂dispersed solution was the first-order reaction.The reaction rate constant equation and the apparent activation energy（E_a）of the K₂O?nSiO₂ based solution with 50%solid content and modulus n is 5 was obtained.According to the research results,the cure reaction process of fireproof solution was optimized.According to the measure results of dynamic DSC analysis of K₂O·nSiO₂ base composite fireproof glass,it is founded that the free water which existent in the cured K₂O·nSiO₂ based solution largely is the key factor affecting the low temperature performance.When the modulus n of the K₂O?nSiO₂ based composite fireproof glass is higher,compared with the lower modulus n of the composite fireproof glass,the free water content in the system is higher.And the resistance to low temperature is poorer.By adding antifreeze can reduce and lock the free water in the system.Adding8%antifreeze to the K₂O?nSiO₂ based composite fireproof glass with the modulus from 4.0 to 4.3,the fireproof glass low temperature performance can reach to-20℃.This kind of the low temperature resistance K₂O?nSiO₂ based composite fireproof glass also has good transmittance,fire resistance and UV irradiation resistance.