Kinetic Study on Solidification of the W-OH Chemical Sand- fixing Material

摘要

A composite based on a hydrophilic polyurethane resin(using W-OH as a product name) has been developed and used as one kind of sand-fixing material. This paper analyzed the solidification mechanism of W-OH, and discussed the relationship between solidification time(?) and temperature from the point of kinetic, and also the solidification time of W-OH aqueous solution with concentrations ranging from 3% to 5% was investigated by changing temperature and solution pH. Finally the apparent activation energy(Ea) and preexponential factor(A) were calculated. The results demonstrate that the solidification mechanism of W-OH is the nucleophilic addition and cross-linking reaction between isocyanato(-NCO) in W-OH and water, the kinetics of solidification follows the first order reaction. The solidification rate accelerates with increase of solution pH, concentration and temperature, and the temperature has the greatest influence on solidification. The preexponential factor(A) increases with solution pH and the concentration of W-OH, however it don't change with temperature. Ea is about 29.1 kJ.mol~(-1) and it don't change with solution pH, concentration and temperature.