Construction grade HPMC & HEMC in building materials
July 26th 2024
Hydroxypropyl methyl cellulose (HPMC) is an odorless, tasteless, non-toxic white powder. The main raw materials of hydroxypropyl methyl cellulose (HPMC) are refined cotton, chloromethane, propylene oxide and other raw materials and chemicals.
Comparison of real and fake HPMC
Pure hydroxypropyl methyl cellulose HPMC is visible to the naked eye and has a low bulk density of 0.3-0.4/ml. Fake HPMC has very good fluidity and a heavier feel, which is obviously different from the appearance of the genuine product.
Pure hydroxypropyl methyl cellulose HPMC aqueous solution is transparent, high light transmission, water retention rate > 97%. Fake HPMC aqueous solution is more dirty, water retention rate is difficult to reach 80%.
Pure hydroxypropyl methylcellulose HPMC should not have the smell of ammonia, starch and alcohol.
A fake HPMC can usually smell all kinds of odors, even if it is odorless, it will feel heavy.
Pure hydroxypropyl methylcellulose HPMC powder is fibrous under a microscope or magnifying glass.
Fake HPMC can be observed as granular solids or crystals under a microscope or magnifying glass.
From which aspects to identify?
Whiteness
Although whiteness does not determine whether HPMC is good or not, if whitening agent is added in the production process, it will also affect its quality. However, most of the good products are white.
Fineness
The fineness of HPMC is usually 80 mesh and 100 mesh. the finer the HPMC, the better it is usually.
Transparency
When hydroxypropyl methyl cellulose (HPMC) is put into water to form a transparent colloid, the greater the light transmission, the less insoluble matter.
Specific Gravity
The larger the ratio, the better. Due to high hydroxypropyl content and high hydroxypropyl content, water retention is better.
Water Retention
The higher the viscosity of cellulose ether, the better the water retention performance. Viscosity is an important parameter of MC performance.
Generally speaking, the higher the viscosity, the better the water retention effect. However, the higher the viscosity, the higher the molecular weight of HPMC, and its solubility will be reduced accordingly, which will have a negative impact on the strength and construction performance of mortar.
The higher the viscosity, the more obvious the thickening effect on the mortar, but not proportional. The higher the viscosity, the more sticky the wet mortar is, as shown by the adhesion of the scraper and the high adhesion to the substrate during construction. But it does not help much to improve the structural strength of the wet mortar itself. The anti-sagging performance during construction is not obvious.
On the contrary, some low to medium viscosity modified methyl cellulose ethers are excellent in improving the structural strength of wet mortar. The greater the amount of cellulose ether added to the mortar, the better the water retention performance, and the higher the viscosity, the better the water retention performance.
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