Melt Production and Antimicrobial Efficiency of Low-Density Polyethylene (LDPE)-Silver Nanocomposite Film

Abstract

Colloidal silver nanoparticles with a size of 5.5± 1.1 nm were prepared by chemical reduction using polyethylene glycol (PEG). Silver nanoparticles were incorporated into low-density polyethylene (LDPE) by melt blending and subsequent hot pressing at 140°C to produce nanocomposite film with an average thickness of 0.7 mm. PEG was added at 5% weight of polymer as a compatibilizer agent in order to prevent agglomeration and provide uniform distribution of nanoparticles in polymer matrix. Antimicrobial activity of silver nanocomposites against Escherichia coli ATCC 13706, Staphylococcus aureus ATCC12600, and Candida albicans ATCC10231 was evaluated by semi-qualitative agar diffusion test and quantitative dynamic shake flask test. Mechanical properties of nanocomposites were not significantly different from silverfree LDPE-containing PEG films (p>0.05), and silver nanoparticles did not form chemical bonding with the polymer. LDPE-silver nanocomposite samples by more than 6.69 ppm silver nanoparticles showed considerable antimicrobial clear zone. LDPE-silver nanocomposite affected growth kinetic parameters of the examined bacteria and is more efficient on S. aureus than E. coli. Polyethylene-silver nanocomposites containing 22.64 ppm silver nanoparticles could reduce 57.8% growth rate and 23.3% maximum bacterial concentration and increase 35.8% lag time of S. aureus. This study shows the potential use of LDPE-silver nanocomposite as antimicrobial active film. Antimicrobial efficiency of silver nanocomposite depends on silver nanoparticles concentration; however, high level of silver nanoparticles may lead to weakening of mechanical properties.

Polyethylene Films Containing Silver Nanoparticles for Applications in Food Packaging: Characterization of Physico-Chemical and Anti-Microbial Properties

“…These results are in agreement with literature, 44 where a better inhibitory effect on Gram-positive S. aureus than Gram-negative E. coli yeast was observed. The antimicrobial action is related to differences between gram-positive and gram-negative bacteria membranes due to the thickness of the peptidoglycan layer.…”

A Review of Poly(Lactic Acid)‐Based Materials for Antimicrobial Packaging

“…To date, one of the extremely challenging AP technologies is the use of antimicrobial additives that can minimize the risk of food spoilage and contamination by suppressing the activities of targeted microorganisms (Labuza and Breene ; Lim and Mustapha ; Mauriello and others ; Joerger ; López‐Mendoza and others ; Sung and others ; Guo and others ). A wide range of additives have been successfully incorporated directly into food products as well as into packaging materials, including organic acids and their salts, bacteriocins, enzymes, chelators such as ethylenediaminetetraacetic acid (EDTA), lactoferrin, and a range of plant extracts (Cooksey ; Sanchez‐Garcia and others ; Jin and Niemira ; Barbiroli and others ; Jokar and others ; Torres and others ). This technology also combines antimicrobial additives with the packaging material that slowly and continuously release the additives over the required period of time and maintain a high concentration of the antimicrobial in the product (Quintavalla and Vicini ).…”

Green Synthesis, Characterization, and Antibacterial Activity of Silver/Polystyrene Nanocomposite

“…For these reasons, the polymeric materials must be protected against microorganisms in order to suppress their growth and dissemination. Owing to the high antimicrobial activity, relatively low cost, and easy production in a polymer-embedded form, nanoscopic silver could be a very adequate filler for such a purpose [6].…”