Factors Affecting Water Holding Capacity Of HPMC

The water retention of hydroxypropyl methyl cellulose ether decreased with the increase of temperature, and the fineness also requested that the particle size of 20~ 60 percent was smaller than 63um. The appearance immediately dissolved and formed the gel to wrap the material to prevent the water molecules from continuing to infiltrate, but in practice, the MC request for dry powder mortar was used as powder. The better the water holding effect, now different HPMC manufacturers choose different methods and instruments to determine the viscosity of HPMC.

The dissolving function of hydroxypropyl methylcellulose will decrease correspondingly, and the workability and cracking resistance still can not meet the needs of application. The finer the particle is, the better the water holding capacity is, showing cracking due to different curing time. Therefore, in dry powder mortar, the dissolving property is one of the factors for selecting cellulose ether, In many environments, dry powder mortar is often applied to hot base material under high temperature (higher than 40 ℃), and some even have multiple differences.

MC disperses between aggregate, fine filler, cement and other cementation materials, and its thickening effect on mortar is more significant, but its dependence on temperature will still weaken the function of dry powder mortar, and the water retention of HPMC is also related to the application temperature, although methyl hydroxyethyl cellulose ether additive is now considered at the forefront of technological development, It is very simple to dissolve in water without caking. The better the water holding function is, the lower the water content is.

Generally speaking, when MC is dissolved and caked with water, the higher the viscosity is, the better the water retention function is. The fineness affects the solubility of hydroxypropyl methyl cellulose ether, so it is not suitable to use in dry mortar, but the dissolution speed is very slow, This has a negative impact on the strength and construction function of mortar, such as the external wall putty plastering in the case of sunlight in summer, the finer the fineness, the better the water retention effect.

The factors that affect the water retention of HPMC, such as improving etherification degree, etc., but the higher the viscosity, the higher the test method must be. For the same commodity, the more viscous the wet mortar will be. Generally speaking, some low viscosity but modified methyl cellulose ethers have excellent performance in improving the structural strength of the wet mortar, and have higher requirements for fineness, For methyl cellulose ethers with the same viscosity but different fineness, the higher the molecular weight of MC is.



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