What are the factors affecting the water retention of hydroxypropyl methyl cellulose?

What are the factors affecting the water retention of hydroxypropyl methyl cellulose?

High-quality hydroxypropyl methyl cellulose HPMC can be uniformly and effectively dispersed in cement mortar and gypsum-based products, and wrap all the solid particles, and form a wetting film, the water in the base in a fairly long time gradually released, and inorganic cementitious materials hydration reaction, so as to ensure the bond strength and compressive strength of the material. Therefore, in the high temperature summer construction, in order to achieve the effect of water retention, it is necessary to add a sufficient amount of high-quality HPMC products in accordance with the formula, otherwise, there will be too fast drying and caused by insufficient hydration, strength reduction, cracking, drums and peeling and other quality problems, but also increase the difficulty of workers construction. And as the temperature decreases, you can gradually reduce the amount of water HPMC added, and can achieve the same water retention effect. The water retention of hydroxypropyl methylcellulose HPMC product itself is affected by temperature and the following factors.

What are the factors affecting the water retention of hydroxypropyl methyl cellulose?

1. hydroxypropyl methylcellulose HPMC homogeneity

Homogeneous reaction of HPMC, methoxy and hydroxypropoxy evenly distributed, high water retention rate.

2. Hydroxypropyl methyl cellulose HPMC thermal gelation temperature

High thermal gel temperature, high water retention rate; conversely, low water retention rate.

3. Hydroxypropyl methyl cellulose HPMC viscosity

When the viscosity of HPMC rises, the water retention rate also rises; when the viscosity reaches a certain level, the increase of water retention rate tends to level off.

4. hydroxypropyl methyl cellulose HPMC addition amount

The greater the addition of hydroxypropyl methyl cellulose HPMC, the higher the water retention rate and the better the water retention effect. In the range of 0.25-0.6% of the added amount, the water retention rate increases faster with the increase of the added amount; when the added amount is further increased, the increasing trend of the water retention rate becomes slower