Preparation, Characterization, and Applications of Some Chitosan Derivatives

Abstract

Chemical modifications of chitosan (Cs) and carboxymethyl chitosan (CMCs) in absence and in presence of silver nanoparticles have been performed; the products were characterized, and then evaluated as antimicrobial agents. The first type of modification was attained by the reaction of Cs (CMCs) with various types of aldehydes to obtain the corresponding chitosan/Schiff-base/AgNPs derivatives. The aldehydes used in this modification are aliphatic, aromatic, and heterocyclic aldehydes as well as some prepared aldehydes of pyrazole derivatives. The second modification was obtained upon reactions of Cs(CMCs) with different carboxylic acids to get Cs(CMCs)/carboxylic acid adducts nanocomposites. Different carboxylic acids as monobasic, dibasic, aliphatic and aromatic acids were utilized to modify Cs (CMCs). Characterization of the prepared compounds via elemental analyses and FT-IR spectroscopy confirmed the chemical structures of the products. SEM micrographs showed the homogeneity and the well distribution of AgNPs in the polymeric matrix, where TEM images showed that the size of the AgNPs ranged from 4 to 45 nm for all derivatives.TGA analysis revealed that the prepared compounds are characterized by good thermal stability. Water uptake determination of the prepared products was also carried out, and the results showed th