The effect of temperature on the water retention of 羟丙基甲基纤维素 (HPMC)
1. Cellulose ether HPMC thermal gel temperature
The high temperature of thermal gel, high water retention; on the other hand, the water retention rate is low.
2. Viscosity of cellulose ether HPMC
When the viscosity of HPMC increases, the water retention rate also increases; when the viscosity reaches a certain level, the increase in water retention rate tends to be flat.
3. Homogeneity of cellulose ether HPMC
HPMC reacts uniformly, methoxy and hydroxypropoxy are uniformly distributed, and the water retention rate is high.
Hydrophilic function and principle of hydroxypropyl methylcellulose HPMC:
High-quality cellulose HPMC can be evenly and effectively dispersed in cement mortar and gypsum-based products, and surround all solid particles and form a wetting film. The water in the matrix is released for a long time through the inorganic glue. The hydration reaction of the coagulated material ensures the bonding strength and compressive strength of the material. Therefore, in high-temperature summer construction, in order to achieve the effect of water retention, high-quality HPMCproducts must be added according to the formula. Otherwise, insufficient hydration may occur due to excessive drying. Reduction, cracking, emptying and falling off and other quality problems also increase the difficulty of the construction personnel. As the temperature decreases, the amount of HPMC added can be gradually reduced, and the same water retention effect can be achieved.
4. Factors such as air temperature, temperature and wind pressure will affect the moisture evaporation rate of cement mortar and gypsum-based products. Therefore, there are differences in the water retention effect of adding the same amount of HPMC products in different seasons. In concrete construction, the addition of HPMC can be increased or decreased to adjust the water retention effect of the slurry. The water retention of methyl cellulose ether at high temperature is an important indicator to distinguish the quality of methyl cellulose ether.
5. Excellent HPMC series products can effectively solve the problem of water retention at high temperature. In high-temperature seasons, especially in hot and dry areas and on the sunny side of thin-layer construction, high-quality HPMC is required to improve the water retention of the slurry. High-quality HPMC has excellent uniformity. The methoxy and hydroxypropoxy groups are evenly distributed on the cellulose molecular chain, which can improve the ability of the oxygen atoms on the hydroxyl and ether bonds to combine with water to form hydrogen bonds. Free water becomes bound water, effectively controlling the evaporation of water caused by high temperature weather, and realizing high water retention.
6. The greater the amount of cellulose HPMC added, the higher the water retention rate and the better the water retention effect. In the range of 4-6 kg, as the added amount increases, the water retention rate increases rapidly; when the addition amount further increases, the increasing trend of the water retention rate becomes slower.
