羧甲基纤维素钠（CMC Na）.docVIP

羧甲基纤维素钠（CMC Na） CMC Na Sodium carboxymethyl cellulose, NaCMC, or CMC, is a water-soluble cellulose ether that changes the viscosity of most commonly used aqueous solutions between several cP to several thousand cP. The simplified formula for NaCMC is as follows: Cell-O-CH2-COONa NaCMC is obtained by the interaction of chloroacetic acid with alkali cellulose. Alkali cellulose itself is produced by the reaction of cellulose with sodium hydroxide. The steps of the alkali cellulose are necessary to simplify the reaction between the etherification agent and the cellulose chain. Degree of substitution (DS) and degree of polymerization (DP) are typical indicators of various grades of NaCMC. 1. degree of substitution and solubility degree of substitution mean the average number of carboxyl sodium groups attached to each cellulose unit. The glucose anhydride on the cellulose molecule has three alcohol groups: one primary alcohol and two secondary alcohols. Three alcohol groups can react with sodium chloroacetate. The primary alcohol group has the greatest reactivity, so the substituent first replaces the group and grows the reactant molecule. The maximum degree of substitution is 3, but the greatest use in industry is the substitution of NaCMC between 0.5 and 1.2. The degree of substitution of 0.2-0.3 is NaCMC, and there is a great difference between the NaCMC with the degree of substitution of 0.7-0.8. The former is only partially soluble in water with a pH of 7, but the latter is completely soluble. Under alkaline conditions, the opposite is true. 2. degree of polymerization and viscosity, polymerization degree refers to the length of cellulose chain, determines the size of viscosity. The longer the cellulose chain, the greater the viscosity, and so does the NaCMC solution. NaCMC molecules exhibit a linear structure, so they can form highly viscous solutions. Viscosity reflects the interaction between molecules. Therefore, products with different degrees of polymerization