mortar additive hpmcMay 11th 2023
Pure HPMC is visually fluffy and has a low bulk density in the range of 0.3-0.4g/ml. The adulterated HPMC has better fluidity and a deeper handle, which is obviously different from appearance.
The pure HPMC aqueous solution is clear, with high light transmittance, and the water retention rate is ≥97%; the adulterated HPMC solution is turbid, and the water retention is difficult to reach 80%.
The purified HPMC should not smell ammonia, starch and alcohol. Adult HPMC can usually smell a variety of flavors, even if it is tasteless, it will feel heavy.
The purified HPMC powder is fibrous under a microscope or magnifying glass; the adulterated HPMC can be observed under a microscope or magnifying glass in granular solids or Crystals.
The Common adulteration methods and identification methods:
The viscosity of the cellulose ether solution can be increased rapidly by adding amide cellulose ether, which cannot be determined with a viscometer. Identification method: Due to the characteristics of amide compounds, the cellulose ether solution is prone to stretching. After the stretching phenomenon is dissolved, no good cellulose ether will appear. If the solution is frozen, it is so-called sticky but not connected.
Add the cellulose ether of starch. Starch is generally insoluble in water, and the solution usually has poor light transmittance. Identification method: Inject the cellulose ether solution,consider adding the blue color of starch.
Add polyvinyl alcohol powder. As we all know, polyvinyl alcohol powders such as 2488 and 1788 are generally cheaper than cellulose ethers, and mixing with polyvinyl alcohol powders can reduce the cost of cellulose ethers.
SLEOCHEM Identification method: This cellulose ether tends to be granular and has a high density. Dissolve quickly with water, and take the solution with a glass rod, there will be more obvious wire drawing.
Summary: Due to its special structure and group, cellulose ether cannot be replaced by other substances. No matter what kind of filler is used, if it is added in large amounts, its water retention capacity will be greatly reduced. The normal 10W viscosity of HPMC in ordinary mortar is 0.15 to 0.2‰, and the water retention rate is 88%. No problem, and the poor quality added to 0.3‰, the water retention rate may not reach 88%. Mortar is often used. The bleeding is more serious. Therefore, the water retention rate is an important indicator to measure the pros and cons of HPMC. Whether it is good or bad, as long as it is added to the mortar, it will be clear at a glance.