Effect of Iignocellulosic Nanoparticles Extracted from Yerba Mate (Ilex paraguariensis) on the Structural, Thermal, Optical and Barrier Properties of Mechanically Recycled Poly(lactic acid)

Abstract

In this work, yerba mate nanoparticles (YMNs) were extracted from Ilex paraguairiencis yerba mate wastes and further used to improve the overall performance of mechanically recycled PLA (PLAR). Recycled PLA was obtained by melt reprocessing PLA subjected to an accelerated ageing process, which involved photochemical, thermal and hydrothermal ageing steps, as well as a final demanding washing step. YMNs (1 and 3 wt. %) were added to the PLAR during the melt reprocessing step and further processed into films. The main goal of the development of PLAR-YMNs bionanocomposites was to increase the barrier properties of recycled PLA, while showing good overall performance for food packaging applications. Thus, optical, structural, thermal, mechanical and barrier properties were evaluated. The incorporation of YMNs led to transparent greenish PLAR-based films with an effective blockage of harmful UV radiation. From the backbone FTIR stretching region (bands at 955 and 920 cm−1), it seems that YMNs favor the formation of crystalline domains acting as nucleating agents for PLAR. The morphological investigations revealed the good dispersion of YMNs in PLAR when they are used in the lowest amount of 1 wt. %, leading to bionanocomposites with improved mechanical performance. Although the addition of high hydrophilic YMNs increased the water vapor transmission, the addition of 1 wt. % of YMNs enhanced the oxygen barrier performance of the produced bionanocomposite films. These results show that the synergistic revalorization of post-consumer PLA and nanoparticles obtained from agri-food waste is a potential way for the production of promising packaging materials that meet with the principles of the circular economy.

Effect of Yerba Mate and Silk Fibroin Nanoparticles on the Migration Properties in Ethanolic Food Simulants and Composting Disintegrability of Recycled PLA Nanocomposites

“…PLA is a biodegradable material; however, newer grades are very resistant and only biodegradable under industrial composting conditions, i.e., approximately 58 • C, a relative produced an improvement in the overall properties of mechanically recycled PLA mainly because a good dispersion of the nanoparticles into the polymeric matrix was achieved. Meanwhile, the incorporation of 3 wt.% of yerba mate nanoparticles tend to aggregate [23]. However, the control of the release of potentially migrant compounds from the packaging material to the foodstuff is of fundamental importance in PLA-based food packaging materials.…”

“…Thus, in the case of mechanically recycled PLA materials, in which the polymer undergoes degradation during the service and recycling process leading to a reduction in the molecular weight with the formation of shorter polymeric chains, an increase in the migration phenomenon is expected. Nevertheless, different results were obtained for recycled PLA-based nanocomposites reinforced with yerba mate and silk fibroin nanoparticles in which the homogeneous distribution of nanoparticles into the polymeric matrix leads to materials with improved overall performance [23,24], and thus with potentially more complex migration processes.…”

Improvement of PBAT Processability and Mechanical Performance by Blending with Pine Resin Derivatives for Injection Moulding Rigid Packaging with Enhanced Hydrophobicity

“…Naturally occurring microorganisms offer the opportunity to enzymatically degrade biodegradable polymers into small molecules (carbon dioxide and water) [7]. However, biodegradable polymers present reduced overall performance with respect to traditional petroleum-based counterparts, such as higher sensitivity to humidity and thermal degradation, as well as poor barrier and mechanical performance, which hinder its massive industrial exploitation [8][9][10]. Among biodegradable polymers, biopolyesters are positioned in the packaging sector as the most suitable polymers to replace petrol-based plastics in food packaging applications; thus, there are many research studies focused on improving biopolyesters' performance, including poly(lactic acid) (PLA), polyhydroxyalkanoates (PHAs) and its derivatives [11], poli(ε-carpolactone) (PCL), and poly(butylene adipate-co-terephthalate) (PBAT) [12][13][14].…”

Influence of plasticizers on the compostability of polylactic acid

“…PLA wastes are potentially recyclable (Agüero et al, 2019;Beltrán, Arrieta, Gaspar, de la Orden, & Urreaga, 2020;Beltrán, Lorenzo, de la Orden, & Martínez-Urreaga, 2016), but although the corresponding sorting technology is already available, no separate recycling stream yet exists (Bioplastics, 2020). Additionally, consumers also have low information regarding where they have to throw away biodegradable plastics after their useful life (Arrieta, Samper, et al, 2017).…”