Potential of Lignins as Antioxidant Additive in Active Biodegradable Packaging Materials

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Abstract Due to their polyphenolic structure lignins bear a number of interesting functional properties, such as antioxidant activity. Natural antioxidants are very much looked for in the aim of protection of light or oxygen sensitive goods and are being used in active packaging. Poly(lactide) (PLA)-lignin films were prepared by twin screw extrusion followed by thermo-compression using two different commercial sources of alkali lignins obtained from gramineous plants. A good dispersion of lignin in the matrix was observed. Mechanical properties of the compounded material were merely diminished and oxygen barrier properties slightly enhanced. The chromatographic study of the lignins revealed that the low molecular weight fraction of both lignins increased during the polymer processing. The migration of low molecular weight compounds in an ethanol/water solution simulating fatty foodstuff was performed and the antioxidant activity of the extract was analysed. It was found that the activity increases with increasing severity of the heat treatment because of the generation of free phenolic monomers during processing. These results open an interesting way for application of lignins as an active compound in packaging materials. Lignins do not impair the mechanical and barrier performance of the polymer and the plastics processing even allows for the generation of active substances.

Kraft lignin as filler in PLA to improve ductility and thermal properties

“…There was a big difference between composites elaborated with PLA and KL and composites with AKL addition. Other study in which was elaborated a PLA/unmodified commercial lignin composite by similar methods were also observed a decrease in the stress at concentrations of 5% and 10% (Domenek et al, 2013). This may be the result for the best interaction between PLA and acetylated Kraft lignin than PLA with unmodified lignin.…”

Effect of processing conditions and lignin content on thermal, mechanical and degradative behavior of lignin nanoparticles/polylactic (acid) bionanocomposites prepared by melt extrusion and solvent casting

“…The measured values of T g in the case of cast systems, at first heating scan, were lower than glass transition temperatures of extruded samples, due to the presence of residual solvent. The glass transition temperature of extruded PLA films containing 1 wt.% of LNPs was slightly lower than the one of the neat PLA, and this may be attributed to a plasticizing effect of a low molecular weight fraction of lignin [31]. When increased amount of lignin was added to PLA, the cold crystallization temperature shifted to lower temperatures in the case of extruded material (from the original 101.7°C to 100.8°C and 96.1°C for E-PLA/1LNP and E-PLA/3LNP, respectively).…”

Natural antioxidants as stabilizers for polymers

“…Both lignin and tannins are more likely applied as additives in food packaging materials because of their antioxidant and antimicrobial activities [147][148][149].…”