HPMC-Hydroxypropyl methyl cellulose introduction
November 21st 2024
1.Water-Holding Capacity
Hydroxy Propyl Methyl Cellulose (HPMC) helps to significantly improve the water-holding capacity of mortar. Just a low level of hydroxypropyl methyl cellulose addition can lead to a significant improvement in the water retention rate of the mortar.
When the addition level is 0.002%, the water retention rate increases from 83% to 88%; while the former is 0.02%, the latter can reach 97%. Meanwhile, low level of hydroxypropyl methyl cellulose addition can also significantly reduce the layering degree and bleeding rate of the mortar. This shows that hydroxypropyl methyl cellulose can not only enhance the water-holding capacity of the mortar but also significantly improve the cohesiveness of the mortar, which is very advantageous to the uniformity of mortar construction quality.
This is one of the most important Hydroxypropyl Methyl Cellulose effects. The building special hydroxypropyl methylcellulose can prevent water from penetrating the wall. An appropriate amount of water staying in the mortar helps to make the cement have a longer time for hydration. The water-holding capacity is proportional to the viscosity of the cellulose ether solution in the mortar, so the higher the viscosity is, the better the water-holding capacity will be; once the water molecules increase, the water-holding capacity will decrease. This is because for the same amount of the building special hydroxypropyl methyl cellulose solution, the increase of water means the decrease in viscosity. The increase of water-holding capacity will lead to extending the curing time of the mortar in the construction.
2. Improving Workability
The application of hydroxypropyl methyl cellulose can improve the workability of mortar.
3. Lubricating Ability
All air-entraining agents have the function of wetting agents, because they can reduce the surface tension and then help the fine powder in the mortar to disperse when mixing with water.
4. Sag Resistance
Another of the hydroxypropyl methyl cellulose effects. Good anti-sagging mortar means no sagging or downward flow hazards during thick-layer construction. The sag resistance can be improved by building special hydroxypropyl methyl cellulose, especially the newly developed building special hydroxypropyl methyl cellulose, which can provide the mortar with better sag resistance.
5.Bubble Content
High bubble content can lead to better yield and workability of the mortar, and reduce the formation of cracks. Meanwhile, it also reduces the strength value, and the “liquefaction” phenomenon occurs. The bubble content usually depends on the stirring time. hydroxypropyl methyl cellulose products are widely used to improve the performance of hydraulic building materials, such as cement and plaster. In the cement-based mortar, it can improve the water-holding capacity, extend the correction time and opening hours, and reduce sagging phenomena.
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