Stabilized nanosilver based antimicrobial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanocomposites of interest in active food packaging

摘要

Antimicrobial silver based nanocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) were successfully synthesized and characterized. For the synthesis, a masterbatch of in situ stabilized silver nanoparticles (AgNPs) produced into a mixed microbial cultures based poly(3-hydroxybutyrate-co-18 mol%-3-hydroxyvalerate) (PHBV18) was used, which was diluted by melt compounding with a commercial poly(3-hydroxybutyrate-co-3 mol%-3-hydroxyvalerate) (PHBV3) material. The incorporated AgNPs (0.04 wt.%) led to a surprising oxygen permeability drop of ca. 56% compared to the neat polymer. The thermal stability and optical properties of the nanocomposites were not significantly modified as compared to the neat PHBV3. Moreover, the antimicrobial performance of the PHBVs-AgNPs films against two of the most common food borne pathogens, Salmonella enterica and Listeria monocytogenes, showed a strong and sustained (even after seven-months) antibacterial activity. This study provides an innovative route to generate fully renewable and biodegradable antimicrobial nanocomposites that could potentially be of interest in film and coating applications such as active food packaging.