Starch/alginate/ Cu-g-C3N4 nanocomposite film for food packaging

In recent years, the researches in food packaging have been focused on the development of biodegradable antimicrobial packaging with outstanding mechanical properties. In the present research, Cu deposited graphitic carbon nitride (g-C3N4) nanoparticles were used as reinforcement and antibacterial agents in the fabrication of starch/sodium alginate (NaAlg) film for food packaging application. For this purpose, g-C3N4 with different loading percent of Cu has been synthesized and the effect of starch/NaAlg ratio, the percentage of nanoparticle in the polymer matrix, and the type of nanoparticles (g-C3N4 and Cu-g-C3N4) on the mechanical properties of the film was evaluated and optimized using Taguchi method. Based on the ANOVA results, the starch/NaAlg ratio with contributions percent of 59.17%, was the most influential factor in the tensile strength of nanocomposite film. The results of the mechanical test showed that the addition of 0.5 wt% Cu5%-g-C3N4 could increase the tensile strength from 23.67 ± 0.7 MPa to 36.57 ± 0.09 MPa. Additionally, the WVP of starch/NaAlg film decreased from (7.5 ± 0.1) × 10−13 kg/m s Pa to (3.05 ± 0.1) × 10−13 kg/m s Pa, after the addition of nanoparticles. Also, results demonstrate that Cu5%-g-C3N4 can effectively hinder the growth of both gram-positive and gram-negative bacteria. Finally, it can be concluded that Cu deposited g-C3N4 nanoparticles can be considered as a promising candidate to enhance the packaging properties of biopolymer films.