Characterization of Hydrolysis Process of a Silane Coupling Agent KH-570

The hydrolysis process of a silane coupling agent KH-570 in deionized water, ethanol, and their mixed medium was characterized by continuous online conductivity testing, respectively. In addition, hydration products of KH-570 in different mediums were analyzed by Fourier transform infrared spectroscopy (FTIR) to correlate with its hydration process. Results indicate that the KH-570 hydrates fast and to a large degree in deionized water, but at the same time, its hydrolysis products condensate together with increasing rate during the hydration process. However, the introduction of ethanol could significantly reduce the degree of the condensation. The hydrolysis degree of KH-570 was relatively large in a mix medium of deionized water and ethanol with the mass ratio of 5:1, and condensation degree of hydrolysis products was also small. KH-570 would hydrate quickly in a hydration medium of colloidal silica, and subsequently, its hydration products would directly react with colloidal silica, which could accelerate the formation of Si-O-Si three-dimensional network structure, and thus promoting the setting of colloidal silica. The hydration of 0.9wt% KH-570 in colloidal silica could be sufficient, and correspondingly, its effect on the coagulation of colloidal silica was better.