stability

1. When the degree of substitution is greater than 0.5, it is easy to dissolve in water into transparent colloid, and CMC with a degree of substitution less than 0.5 is difficult to dissolve in water, but it can dissolve in alkaline water solution. CMC is generally insoluble or only able to swell in organic solvents, but it can be dissolved in 35% ethanol solution. CMC has good dispersing ability, strong emulsifying ability for grease and wax, and can be used as emulsifier. It is a polymer electrolyte, with strong water absorption and water retention capacity, and its water retention is related to the salt content in water. CMC often exists in the form of polymolecular aggregates in water and has a high viscosity. As the temperature increases, the viscosity decreases. When pH is 5 ~ 9, the solution viscosity is stable. When pH < 3, precipitation and hydrolysis occur at the same time. When pH > 10, the viscosity decreased slightly. The viscosity of CMC solution will also decrease under the action of microorganisms. Turbidity occurs when calcium ions are introduced into CMC aqueous solution, and the addition of high-priced metal ions such as Fe3+ and Al3+ can precipitate CMC or form a gel.

2. The aqueous solution is thermally stable, and the water-soluble viscosity varies with the value of p H and the degree of polymerization, and decreases with the increase of temperature.