Carboxymethyl cellulose (Sodium Carboxymethyl Cellulose) referred to as CMC, is a surface active colloid polymer compound, is a kind of odorless, tasteless, non-toxic water-soluble cellulose derivative, is made of absorbent cotton through physical-chemical treatment. The obtained organic cellulose binder is a kind of cellulose ether, and its sodium salt is generally used, so its full name should be called sodium carboxymethyl cellulose, namely 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 slurries 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 particles, infiltrating and connecting particles well, so that a higher strength refractory body can be obtained;
2. Since carboxymethyl cellulose is an anionic polymer electrolyte, it can reduce the interaction between particles after being adsorbed on the surface of the particles, and play the role of a dispersant and protective colloid, thus improving the density and strength of the product and reducing after-burning. Inhomogeneity of organizational structure;
3. Using carboxymethyl cellulose as a binder, there is no ash after burning, and there are few low-melting substances, which does not affect the use temperature of the product.
Product Features
1. CMC is a white or slightly yellow fibrous granular powder, tasteless, odorless, non-toxic, easily soluble in water, and forms a transparent viscous colloid, 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 temperature change, the acidity and alkalinity of the solution change. Under the influence of ultraviolet radiation 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 such as formaldehyde, phenol, benzoic acid, organic mercury compounds, etc. can be selected.
2. CMC is the same as other polymer electrolytes. When it dissolves, it first produces a swelling phenomenon, and the particles adhere to each other to form a film or viscose, which makes it impossible to disperse, but dissolves slowly. 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. In the atmosphere, the average water content of CMC 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 water content is above 26%, and the product water content 10% or less. Therefore, product packaging and storage should pay attention to moisture-proof.
4. Zinc, copper, lead, aluminum, silver, iron, tin, chromium and other heavy metal salts can precipitate the CMC aqueous solution. Except for the salt-based lead acetate, the precipitate can still be redissolved in sodium hydroxide or ammonium hydroxide solution. .
5. Organic or inorganic acids will also cause precipitation to the solution of this product. The precipitation phenomenon varies with the type and concentration of the acid. Generally, precipitation occurs when the pH is below 2.5, and it can be recovered after neutralization with alkali.
6. In salts such as calcium, magnesium and table salt, it does not have a precipitation effect on the CMC solution, but it affects the viscosity reduction.
7. CMC is compatible with other water-soluble glues, softeners and resins.
8. Films drawn from CMC, immersed in acetone, benzene, butyl acetate, carbon tetrachloride, castor oil, corn oil, ethanol, ether, dichloroethane, petroleum, methanol, methyl acetate, methyl ethyl acetate at room temperature Ketone, toluene, turpentine, xylene, peanut oil, etc. can be unchanged within 24 hours
Post time: Nov-07-2022