Synthesis, characterization, swelling and antimicrobial efficacies of chemically modified chitosan biopolymer

Abstract

Three heterocyclic compounds namely: (Z)-4-benzylidene-2-phenyl-1,3-oxazol-5-one (A), (Z)-4-(4-methoxybenzylidene)-2-phenyl-1,3-oxazol-5-one (B), (Z)-4-(2-thienyl methylene)-2-phenyl-1,3-oxazol-5-one (C) were prepared in one step reaction between hippuric acid and benzaldehyde, p-anisaldehyde and thiophene-2-carboxaldehyde, respectively. The prepared compounds were characterized using FTIR and 1 H NMR spectroscopy. Furthermore, chitosan was prepared from alkaline treatment of shrimp shells. These compounds were used to chemically modify chitosan biopolymer. The obtained modified chitosan biopolymers were characterized using FTIR spectroscopy. The swelling properties of the modified chitosan biopolymers were studied at different immersion times, temperature of 25–70 °C and at a wide range of pH of 2–9. The increase of immersion time and temperature increased the swelling efficiency, as well as, increasing the acidity and alkalinity of the aqueous solution increased the swelling than the moderate pH values at 5–6. The antimicrobial efficacies of the modified chitosan biopolymers were determined using agar diffusion technique against different strains of bacteria and fungi. The antimicrobial assay showed excellent activity of the modified biopolymers. The high antimicrobial activities were correlated and rationalized to the chemical structure of the heterocyclic moieties used in the chemical modification of chitosan.