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Synthesis, thermal and antimicrobial studies of some Schiff bases of chitosan


The Schiff bases of chitosan are synthesized by the reaction of chitosan with different aromatic aldehydes. The structures of the biopolymeric Schiff bases are characterized by Fourier transform infrared spectroscopy, 1H-NMR spectroscopy and elemental analysis (C, H, N). The 1H NMR spectroscopy is used to determine degree of deacetylation of chitosan and degree of substitution of Schiff bases. The Schiff base polymers have greater degrees of substitution varying from 65 to 88.5 %. Thermogravimetry of Schiff base polymers shows that they have nearly the same decomposition temperature as the chitosan, indicating that Schiff bases are thermally stable. The antimicrobial activities of chitosan and its Schiff bases are tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Aspergillus niger and found that the antimicrobial activities of the Schiff bases of chitosan were stronger than those of chitosan.

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One of the authors, Sohan Lal, is extremely thankful to the Council of Scientific and Industrial Research and University Grant Commission, New Delhi, India, for providing the research grant.

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Correspondence to Sohan Lal.

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Lal, S., Arora, S. & Sharma, C. Synthesis, thermal and antimicrobial studies of some Schiff bases of chitosan. J Therm Anal Calorim 124, 909–916 (2016).

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  • Chitosan
  • Schiff bases
  • TG
  • Antimicrobial activity
  • FTIR
  • 1H NMR