Bionanocomposites containing SnO2 with improved chemical resistance and hydrophobic behaviours for applications in food packaging industry

The influence of poly(asparagine-co-phenylalanine) (P(Asn-co-Phe)/SnO2) on the protection performance of epoxy coating was investigated. The electrochemical impedance spectroscopy (EIS) analysis indicates the better protection against coating degradation of epoxy (EP)−P(Asn-co-Phe)/SnO2 nanocomposite on tinplate compared to that of pure epoxy coatings. The coating resistance (Rcoat) of the EP−P(Asn-co-Phe)/SnO2 nanocomposite is found to be 3854.70 kΩ·cm2. The Rcoat of EP−P(Asn-co-Phe)/SnO2 nanocomposite coating is found to be over 38 times greater than that of the EP coating. Scanning electrochemical microscopy (SECM) analysis shows less current distribution for the EP−P(Asn-co-Phe)/SnO2. The analyses of degradation products by XRD and SEM/EDX confirm the influence of functionalized SnO2 particles on the protecting ability of epoxy coating. The hydrophobic nature of the EP−P(Asn- co-Phe)/SnO2 nanocomposite coating (θ=133°) is confirmed by water contact angle measurement. The resultant nanocomposite coatings display enhanced mechanical properties. The results show that the EP−P(Asn-co-Phe)/SnO2 nanocomposite in wells increased the antibacterial activity as compared with pure EP. Therefore, it is concluded that the newly synthesized EP−P(Asn-co-Phe)/SnO2 nanocomposite provides an outstanding barrier and mechanical properties due to the addition of P(Asn-co-Phe)/SnO2 nanoparticles to the epoxy matrix, which obstructs the degradation of materials and assists in prolonging the life of the coated steel.