Description
Carboxymethylcellulose sodium salt: a kind of cellulose derivate.
Carboxymethylcellulose sodium salt (Sodium carboxymethyl cellulose or CMC) is one of the most essential products of cellulose ethers, which are formed by natural cellulose modification as a kind of cellulose derivate with an ether structure. Because the acid form of CMC has poor water solubility, it is usually preserved as sodium carboxymethylcellulose, widely used in many industries and regarded as monosodium glutamate in industry. It is a non-toxic and biodegradable water-soluble polymer used as an adhesive and cross-linking agent in the pharmaceutical industry. CMC could be used as flocculating agent, chelating agent, emulsifier, thickening agent, water-retaining agent, sizing agent, film-forming material, and so on. CMC is also widely applied in electronics, pesticides, leather, plastics, printing, ceramics, and the daily-use chemical industry. Moreover, due to its excellent properties, wide application, and developing potential fields, CMC has broad application prospects.
Physical properties
Sodium carboxymethyl cellulose (CMC) is an anionic cellulose ether, with white or slightly yellow flocculent fiber powder or white powder appearance, odorless, tasteless, non-toxic; easily soluble in cold water or hot water, forming a certain viscosity clear solution[2]. The solution is neutral or slightly alkaline, insoluble in ethanol, ether, isopropanol, acetone and other organic solvents, soluble in 60% water-containing ethanol or acetone solution. It is hygroscopic, stable to light and heat, the viscosity decreases with the increase of temperature, the solution is stable at pH 2-10, pH is lower than 2, there is solid precipitation, and the viscosity decreases when pH is higher than 10. The discoloration temperature is 227℃, the carbonization temperature is 252℃, and the surface tension of 2% aqueous solution is 71mn/n.
Uses
Sodium carboxymethylcellulose is readily soluble in water and is insoluble
in organic solvents. The material is used as a soil-suspending agent in
detergents, suspending agent in latex paints and as an adhesive; it is also used
as a stabilizer in food products such as ice cream.
Application
Carboxymethyl cellulose (CMC) is a non-toxic and odorless white flocculent powder with stable performance and is easily soluble in water. Its aqueous solution is a neutral or alkaline transparent viscous liquid, soluble in other water-soluble glues and resins, and insoluble. in organic solvents such as ethanol. CMC can be used as adhesive, thickener, suspending agent, emulsifier, dispersant, stabilizer, sizing agent, etc. Sodium carboxymethyl cellulose (CMC) is the product with the largest output, the most widely used and the most convenient use among cellulose ethers, commonly known as "industrial monosodium glutamate".
Preparation
Sodium carboxymethylcellulose is prepared from alkali cellulose and sodium
monochloroacetate. The reaction may be represented as follows:
The extent of carboxymethylation may be regulated; commercial materials
generally have a degree of substitution within the range 0.5-0.85.
