MHEC MH20M

Specification of MHEC MH20M

Application of MHEC MH20M

KimaCell^® MHEC MH20M methyl hydroxyethyl cellulose is used in gypsum slurry to have obvious thickening effect. At room temperature, with the increase of the viscosity and dosage of cellulose ether, its thickening effect becomes more obvious. However, as the temperature increases, the viscosity of cellulose ether decreases, its thickening effect weakens, the yield shear stress and plastic viscosity of the gypsum mixture decrease, the pseudoplasticity weakens, and the workability becomes poor.

Cellulose ether improves the water retention of gypsum, but as the temperature increases, the water retention of modified gypsum also decreases significantly, and even completely loses the water retention improvement effect at 60 °C. The water retention rate of gypsum slurry was significantly improved by cellulose ether, and the water retention rate of HPMC modified gypsum slurry with different viscosities gradually reached the saturation point with the increase of the content. The water retention of gypsum is generally proportional to the viscosity of cellulose ether, and has little effect at high viscosity.

The internal factors of the water retention of cellulose ethers changing with temperature are closely related to the microscopic morphology of cellulose ethers in the liquid phase. At a certain concentration, cellulose ether tends to aggregate to form large colloidal associations, blocking the water delivery channel of the gypsum mixture to achieve efficient water retention. However, as the temperature rises, due to the thermal gelation properties of cellulose ether itself, the previously formed large colloidal associations re-disperse, resulting in a decrease in water retention.