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The development of green nanocomposites based on biopolymers and bio-based nanofillers has attracted over the recent years the attention of academic and industrial research. Indeed, these nanocomposites could replace some oil-derived polymers and thus helping to overcome environmental problems. In this regard, PLA as matrix and polysaccharide nanocrystals as fillers are the most promising components to obtain high-performance green bio-nanocomposites suitable for different applications, particularly for packaging and biomedical applications. Indeed, at present, due to its processability, mechanical and biological properties, as well as its commercial availability, poly(lactic acid) (PLA) possesses one of the highest potentials among biopolymers whereas polysaccharide nanocrystals can be considered the most promising bio-based reinforcements due to their availability, renewability, versatility, biodegradability and high aspect ratio. Aim of this review is to give an overview on the preparation routes and main properties of PLA/polysaccharide nanocomposites highlighting the main differences among the three main polysaccharide nanocrystals, i.e. cellulose, chitin, and starch

Polyethylene-co-vinylacetate (EVA) films with different concentrations (3.5 wt% and 7 wt%) of essential oil constituents, carvacrol or cinnamaldehyde, were prepared and characterized by mechanical, antibacterial and antibiofilm properties. The incorporation of the compounds into copolymer films affected their elastic modulus, tensile stress and elongation at break. Carvacrol and cinnamaldehyde act as plasticizers which reduce the intermolecular forces of polymer chains, thus improving the flexibility and extensibility of the film. The analysis of the surface characteristics demonstrated that essential oil constituents lowered the contact angle values without causing any remarkable variation of the surface roughness. The films allowed progressive diffusion of the bioactive molecules and the kinetic of release was correlated with the damaging effect on bacterial growth. The kill curves proved that the film with essential oil constituents (7 wt%) had a significant bactericidal effect (reduction of 4 and 2 log CFU) against Staphylococcus aureus and Escherichia coli and a bacteriostatic effect against Staphylococcus epidermidis and Listeria monocytogenes (reduction of about 1 log CFU). With regard to biofilm formation the biomass formed on polymeric films surface was significantly reduced if compared with the pure copolymer control. The results were confirmed by fluorescence microscopy images by Live/dead staining. The reduction in the surface tension coupled to an inherent bactericidal property of carvacrol and cinnamaldehyde could in turn affect the initial attachment phase of bacteria and compromise the normal biofilm development.

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