Structural unit of sodium carboxymethyl cellulose
Everyone is quite familiar with sodium carboxymethyl cellulose, because this product has a wide range of applications, outstanding performance and good quality, but these are inseparable from the structural units of the CMC-Na molecular chain, among which the product The structural units are divided into three types, which can be understood through the following contents.
1. Contains an additional secondary hydroxyl group on the non-reducing unit. The reducing end unit is hemiacetal, has reducing ability, is sensitive to various oxidizing agents, can be oxidized into carboxylic acid, and can be used to determine the number average molecular weight of sodium carboxymethyl cellulose (end group method).
2. The reaction performance of the reducing end unit is low, the average degree of polymerization is low, and the reaction performance is high. Among them, the polymerization is too low (DP<200) and the content of too high part is too large to deteriorate the reaction performance.
3. The middle unit is all composed of anhydroglucose units. Since the degree of polymerization of the product is usually very high, although the end group has a non-negligible influence on the chemical reaction of sodium carboxymethyl cellulose, the morphology of cotton fiber is mainly The nature of is still determined by the intermediate unit.
Since most of the etherification reaction process does not change the degree of polymerization of the product much, the distribution of the degree of polymerization of the ether product mainly depends on the distribution of the degree of polymerization of the original raw material of sodium carboxymethyl cellulose.
In summary, the structural units of sodium carboxymethyl cellulose are divided into non-reducing end units, intermediate units and reducing end units. The different units have different functions in the product, and their respective performances can make CMC-Na Performance is improved and product usage efficiency is increased.