Development and Property Evaluation of Poly (Lactic) Acid and Cellulose Nanocrystals Based Films with Either Silver or Peptide Antimicrobial Agents: Morphological, Permeability, Thermal, and Mechanical Characterization

The main aim of this paper is to report the impact of the addition of cellulose nanocrystals (CNC) on the thermal, mechanical, and permeability properties of poly (lactic acid). The thin films were prepared using a modified solvent casting method. The films were fortified with either of two antimicrobial agents: silver (Ag) nanopowder or a peptide. The microstructure, morphology, oxygen and water vapour permeability, mechanical, and thermal behaviour were investigated.It was found that thepresence of the antimicrobial agents does not adversely affect the thermal properties investigated. But, addition of greater than 0.75 % (wt.) peptide into the thin films resulted in a reduction of the mechanical properties. In all cases, there were significant reductions in oxygen and water vapour permeability. For example, for the PLA+CNC+Ag systems, there were reductions up to 50 and 40 %, respectively. The holistic interaction of the Ag nanopowder and CNC resulted in significantly better reduction in the above values. The permeability values of the studied plastics are comparable to those of commercial plastics currently on the market used for packaging.