hydroxypropyl methylcellulose HPMC in Plastering MortarFebruary 2nd 2023
The production process of HPMC is mainly a polysaccharide-based ether product produced by alkalization and etherification of wood pulp or cotton fibers (domestic). Since it has no charge, it reacts with no charged ions in the gelling material, and its performance is stable. In addition, it is less expensive than other types of cellulose ethers, which makes it ideal for dry mix mortars.
HPMC is often used in dry mix mortar as water retention and thickening agent. It can increase the wet viscosity of fresh mortar and prevent segregation. Water retention is also important; as it allows the cementitions material to have more time to hydrate after the mortar has been applied. A significant increase in water retention can be achieved by adding a small amount of HPMC to the dry mix mortar. When the content reaches a certain level, the tendency to increase water retention slows down. As the ambient temperature increases, the water retention capacity of HPMC generally decreases. However, some modified HPMCs have better water retention capacity even at high temperatures. It also has air-entraining properties, which improve mortar’s workability by introducing fine air bubbles.
For dry mix mortar, the addition of a little HPMC can significantly improve the performance of the wet mortar. HPMC has been shown to be an important additive affecting the construction performance of mortar.