Hydroxypropyl methylcellulose is easily soluble in cold water, but hot water will dissolve it. However, its gelation temperature in hot water is significantly higher than that of methyl cellulose. The dissolution in cold water is also much better than methyl cellulose.
The viscosity of hydroxypropyl methylcellulose is related to the molecular weight, and the viscosity is high when the molecular weight is large. Temperature will also affect its viscosity, as the temperature increases, the viscosity decreases. But its high viscosity is lower than methyl cellulose. The water retention capacity of hydroxypropyl methyl cellulose depends on its added amount, viscosity, etc., and its water retention rate is higher than that of methyl cellulose.
Hydroxypropyl methylcellulose is stable to acid and alkali, and its aqueous solution is stable in the range of pH = 2~12. Caustic soda and lime water have little effect on its performance, but alkali can accelerate its dissolution and slightly increase its viscosity. Hydroxypropyl methyl cellulose is stable to ordinary salts, but when the concentration of the salt solution is high, the viscosity of the hydroxypropyl methyl cellulose solution tends to increase. Hydroxypropyl methyl cellulose can be mixed with water-soluble polymers to form a uniform and high-viscosity solution.
Hydroxypropyl methyl cellulose has better enzyme resistance than methyl cellulose, and the possibility of enzymatic degradation of its solution is lower than that of methyl cellulose.