Carboxymethyl Cellulose (Sodium Carboxymethyl Cellulose), referred to as CMC, is a polymer compound of surface active colloid. It is an odorless, tasteless, non-toxic water-soluble cellulose derivative. The obtained organic cellulose binder is a kind of cellulose ether, and its sodium salt is generally used, so its full name should be sodium carboxymethyl cellulose, that is, CMC-Na.
Like methyl cellulose, carboxymethyl cellulose can be used as a surfactant for refractory materials and as a temporary binder for refractory materials.
Sodium carboxymethyl cellulose is a synthetic polyelectrolyte, so it can be used as a dispersant and stabilizer for refractory mud and castables, and it is also a temporary high-efficiency organic binder. Has the following advantages:
1. Carboxymethyl cellulose can be well adsorbed on the surface of the particles, well infiltrated and connected to the particles, so that high-strength refractory blanks can be produced;
2. Since carboxymethyl cellulose is an anionic polymer electrolyte, it can reduce the interaction between particles after being adsorbed on the particle surface, and act as a dispersant and protective colloid, thus improving the density and strength of the product and reducing the afterburning Inhomogeneity of organizational structure;
3. Using carboxymethyl cellulose as binder, there is no ash after burning, and there are very few low-melting materials, which will not affect the service temperature of the product.
Product Features
1. CMC is white or yellowish fibrous granular powder, tasteless, odorless, non-toxic, easily soluble in water, and forms a transparent viscous colloid, and the solution is neutral or slightly alkaline. It can be stored for a long time without deterioration, and it is also stable under low temperature and sunlight. However, due to the rapid change of temperature, the acidity and alkalinity of the solution will change. Under the influence of ultraviolet rays and microorganisms, it will also cause hydrolysis or oxidation, the viscosity of the solution will decrease, and even the solution will be corrupted. If the solution needs to be stored for a long time, suitable preservatives can be selected, such as formaldehyde, phenol, benzoic acid, and organic mercury compounds.
2. CMC is the same as other polymer electrolytes. When it dissolves, it will first swell, and the particles will adhere to each other to form a film or viscose group, so that they cannot be dispersed, but the dissolution is slow. Therefore, when preparing its aqueous solution, if the particles can be uniformly wetted first, the dissolution rate can be significantly increased.
3. CMC is hygroscopic. The average moisture of CMC in the atmosphere increases with the increase of air temperature and decreases with the increase of air temperature. When the average temperature of room temperature is 80%–50%, the equilibrium moisture is above 26%, and the product moisture less than 10%. Therefore, product packaging and storage should pay attention to moisture-proof.
4. Heavy metal salts such as zinc, copper, lead, aluminum, silver, iron, tin, chromium, etc., can cause precipitation in CMC aqueous solution, and the precipitation can still be re-dissolved in sodium hydroxide or ammonium hydroxide solution except for basic lead acetate.
5. Organic or inorganic acids will also cause precipitation in the solution of this product. The precipitation phenomenon is different due to the type and concentration of the acid. Generally, precipitation occurs below pH 2.5, and it can be recovered after neutralization by adding alkali.
6. Salts such as calcium, magnesium and table salt do not have a precipitation effect on the CMC solution, but affect the reduction of viscosity.
7. CMC is compatible with other water-soluble glues, softeners and resins.
8. The film drawn by CMC is immersed in acetone, benzene, butyl acetate, carbon tetrachloride, castor oil, corn oil, ethanol, ether, dichloroethane, petroleum, methanol, methyl acetate, methyl ethyl ether at room temperature Ketone, toluene, turpentine, xylene, peanut oil, etc. may not change within 24 hours
Post time: Jan-03-2023