Investigation of the physical and antimicrobial properties of sodium alginate - agar based bionanocomposite film containing nanosilver and cellulose nanofiber

In this study, antimicrobial quaternary sodium alginate-agar-cellulose nanofiber (CNF)-silver nanoparticles (Ag) bionanocomposite films were prepared by casting method and the effect of CNF (1, 5 and 10% wt) and Ag (0.1 and 0.5% wt) concentrations on the physical (structural, thermal, mechanical and barrier properties) and antimicrobial properties of the bionanocomposites was studied. Water vapor permeability (WVP) of alginate-agar films decreased and mechanical strength increased by increasing CNF and Ag content. However, the water vapor barrier and mechanical properties diminished by increasing of CNF content to 10%, due to the aggregation of nanofibers. The film containing 5% CNF and 0.5% Ag showed the highest tensile strength (23.07 MPa) and lowest WVP (1.07×10-10 g/m.s.Pa). Melting temperature increases by adding CNF, but the effect of CNF is more than Ag. Also, the films containing Ag showed lethal effect against E.coli. CNF, decreased Ag antimicrobial activity by controlling the release of Ag nanoparticles. Overall, resulted bionanocomposite film, exhibited significant improvement in barrier, mechanical, thermal and antimicrobial properties that revealed that it could be a good candidate for using as active packaging of foods.