Carboxymethyl cellulose

Carboxymethyl cellulose is a product substituted with carboxymethyl groups of cellulose. Depending on its molecular weight or degree of substitution, it can be a fully soluble or insoluble polymer, which can be used as a weakly acidic cation exchanger to separate neutral or basic proteins. Carboxymethyl cellulose can form high viscosity colloids, solutions, adhesion, thickening, flow, emulsifying dispersion, shaping, water retention, protective colloids, film molding, acid resistance, salt resistance, suspension and other characteristics, and is physiologically harmless Therefore, it has been widely used in the production of food, medicine, daily chemical, petroleum, paper, textile, construction and other fields.

  The appearance of carboxymethyl cellulose CMC is white or light yellow flocculent fiber powder or white powder, odorless, odorless, non-toxic; easily soluble in cold or hot water to form a gel, the solution is neutral or slightly alkaline, insoluble Organic solvents such as ethanol, diethyl ether, isopropanol, and acetone can be dissolved in 60% ethanol or acetone solution in water. It is hygroscopic, stable to light and heat, and the viscosity decreases with increasing temperature. The solution is stable at a pH of 2-10, the pH is lower than 2, solids precipitate, and the viscosity is lower than 10. Discoloration temperature is 227 ° C, carbonization temperature is 252 ° C, and surface tension of 2% aqueous solution is 71mn / n.

Uses: Sodium carboxymethyl cellulose (CMC) is the product with the largest output, most widely used and most convenient use among cellulose ethers, commonly known as "industrial monosodium glutamate".

  The important characteristics of CMC are the formation of high-viscosity colloids, solutions, adhesion, thickening, flow, emulsification, dispersibility, water retention, protective colloids, film molding, acid resistance, salt resistance, suspension, etc., and physiologically harmless. It is widely used in the production of food, medicine, daily chemical, petroleum, paper, textile, construction and other fields.

CMC quality index, main use, performance, characteristics (Note: The viscosity is measured by NDJ-79 viscometer, 2% aqueous solution, 25 ℃)

  The CMC is directly mixed with water to prepare a paste-like glue solution. When configuring the CMC paste, first add a certain amount of clean water to the batching tank with a stirring device. With the stirring device turned on, sprinkle the CMC into the batching tank slowly and evenly, keep stirring to make the CMC Fully fused with water, CMC can fully dissolve. When dissolving the CMC, the reason why it should be uniformly distributed and continuously stirred is to "in order to prevent the problem of agglomeration, agglomeration, and reduction of the amount of CMC when the CMC meets water", and to improve the dissolution rate of CMC. The time of stirring and the time of complete dissolution of CMC are two different concepts. Generally speaking, the time of stirring is much shorter than the time required for complete dissolution of CMC. The time required for the two depends on the specific situation.

The basis for determining the stirring time is: when the CMC is uniformly dispersed in the water and there are no obvious large agglomerates, the stirring can be stopped to allow the CMC and water to permeate and fuse with each other in a static state.

The basis for determining the time required for CMC to completely dissolve is as follows:

(1) CMC and water are completely bonded, and there is no solid-liquid separation between the two;

(2) The mixed paste is in a uniform state, and the surface is smooth and smooth;

(3) The color of the mixed paste is nearly colorless and transparent, and there is no particulate matter in the paste. The time required for the CMC to be mixed with water from the time it is put into the batch tank is 10 to 20 hours.