Poly(lactic acid)/silver/benzyl dodecyl dimethylammonium modified montmorillonite nanocomposite with antifungal activity for food packaging application

Active biodegradable food packaging with antimicrobial properties is desirable for prolonging the shelf life of food products while minimising waste streams originating from the food supply chain. In the present work, a novel antifungal nanocomposite was prepared by a two-step melt-blending process using poly(lactic acid) (PLA) incorporated with 5 and 8 php of modified clay. The modified clay consisted of sodium montmorillonite (Na+-Mt) +-Mt) modified with silver (Ag) and benzyl dodecyl dimethylammonium chloride (BDAC) at different Ag and BDAC ratios. X-ray diffraction spectra and photomicrographs revealed the distribution of Ag particles and modified Mt layers in the PLA matrix, resulting in an intercalated structure. The antifungal activity of the PLA-based nanocomposites was tested against some foodborne pathogenic fungi Penicillium roqueforti and Fusarium moniliforme. . The tensile strength and elongation at break of the nanocomposites decreased, whereas Young's modulus increased compared with neat PLA. Incorporating 5 php of Ag20/BDAC80-Mt into the nanocomposite resulted in the highest impact strength. The water vapour permeability of the nanocomposite was comparable to that of neat PLA. Differential scanning calorimetry (DSC) showed a decrease in the T-g and T-cc of the nanocomposites, although the Tm did not change. For the PLA/Ag20/BDAC80-Mt-5 nanocomposite, the overall migration in distilled water, acetic acid (3%, w/v), and ethanol (10%, v/v) was below 10 mg/dm(2). Overall, the present work demonstrated the potential of the modified clay for developing antifungal active bionanocomposites for food packaging applications.