Properties of Carboxymethyl Chitosan
Carboxymethyl chitosan is a type of chitin derivative obtained through the carboxymethylation reaction of chitosan. Due to the presence of free amino groups in the chitosan molecule, the substituting groups can enter both O and N positions during the reaction, resulting in corresponding products such as O-carboxymethyl chitosan, N-carboxymethyl chitosan, and N,O-carboxymethyl chitosan. When chitosan reacts with monochloroacetic acid in an alkaline medium, the substitution reaction is limited to the primary hydroxyl group at C6, generating O-carboxymethyl chitosan. Chitosan reacts with glycolic acid to form a water-soluble gelatinous imine (Schiff base), which is then reduced with an appropriate reducing agent such as cyanoborohydride, leading to a substitution reaction only at the primary amine group at C2 and producing N-carboxymethyl chitosan. When chitosan reacts with monochloroacetic acid in a concentrated alkaline solution under properly controlled reaction conditions, N,O-carboxymethyl chitosan can be obtained. Tianya Chemical specializes in producing high-quality carboxymethyl chitosan, ensuring consistent performance across these derivative types for diverse industrial needs.
Excellent Performances of Carboxymethyl Chitosan
(1) Water Solubility
The water solubility of carboxymethyl chitosan is not only due to its nature as a carboxylate salt that dissolves in water but also because the introduction of carboxymethyl groups disrupts the secondary structure of the chitosan molecule, significantly reducing its crystallinity to almost amorphous. Carboxymethyl chitosan with a degree of substitution greater than 0.6 is easily soluble in water; the higher the degree of substitution, the better the water solubility and the higher the transparency of the solution.
(2) Moisturizing Property
The carboxyl and amino groups on carboxymethyl chitosan are both hydrophilic groups with strong water absorption. The moisture absorption of a 0.25% carboxymethyl chitosan solution is equivalent to that of a 20% glycerol solution, and the viscosity of the solution remains constant.
(3) Film-Forming Property
Carboxymethyl chitosan has good film-forming ability. The films formed are glossy, transparent, flexible, and have good air permeability.
(4) Polymer Properties
Carboxymethyl chitosan has a stabilizing effect on colloids, as well as thickening, gelling, and bubble-stabilizing effects.
(5) Safety and Non-Toxicity
Carboxymethyl chitosan is safe, non-toxic, and harmless.
