Structure and properties of chitin/alginate blend membranes from NaOH/urea aqueous solution

Chitin/alginate (CA) blend membranes were successfully prepared from 8 wt% NaOH/4 wt% urea aqueous solution by coagulating with 0.5 M CaCl2 aqueous solution containing 5 wt% HCl. Morphology, mechanical properties, thermal stability, and antimicrobial effects of the membranes were investigated by scanning electron microscopy, IR and UV spectroscopes, X-ray diffraction, tensile tests, thermogravimetric analysis, water swelling and antimicrobial tests. The CA blends were miscible when the content of alginate was range from 33 to 67 wt%. The crystallinity of the blend membranes decreased with an increase of alginate. Comparing with chitin membranes, the tensile strength and breaking elongation of the blend membranes were obviously improved in dry and wet states. The best values of the tensile strength and breaking elongation were 48 MPa and 27%, respectively. All the blend membranes still retained obvious antimicrobial effects toward S. aureus and E. coli. Therefore, they showed potential for biomedical application.