Mechanical recycling of poly(lactic acid): Evaluation of a chain extender and a peroxide as additives for upgrading the recycled plastic.

Beltrán, Freddys R.; Infante, Celia; Orden, Ma Ulagares de la; Urreaga, Joaquín Martínez

doi:10.1016/j.jclepro.2019.01.206

Cited by 70 publications

(48 citation statements)

References 23 publications

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“…One of the main problems during the recycling of PLA is its thermal degradation during reprocessing which involves several mixing cycles at high temperatures 7,8 . The thermomechanical degradation process of PLA is very complex, including various nonradical and radical reactions 9 .…”

Section: Introductionmentioning

confidence: 99%

Multiscale analysis on multiextruded poly(lactic acid)/organoclay nanocomposites: Insights into the underlying mechanisms of thermomechanical degradation

Chen

et al. 2020

Polymers for Advanced Techs

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Due to the growing market and the relatively high price of poly(lactic acid) (PLA), the possibility to recycle PLA has attracted a tremendous attention, aiming to reduce the environmental impact related to the life cycle of PLA-based products. However, the comprehensive structural and properties changes of PLA and PLA/clay nanocomposites induced by reprocessing are still not clear. In this work, PLA and its organoclay nanocomposites (PCN5) were subjected to repeated extrusion for 1 and 4 cycles to reveal their recycling characteristics by the observation of the changes in the microstructure, thermal and mechanical properties. Gel permeation chromatography, rheology and morphology analyses were utilized to deeply explore effects of the cycle number on the evolution of chemical structures and clay dispersion. It is found that reprocessing leads to a significant reduction in the weight average molecular mass of PLA by 24.0% and of PCN5 by 37.3%, whereas a more uniform dispersion of clay and a stronger clay-polymer interaction are also found after reprocessing. A direct correlation between the molecular chain scission and deterioration of thermal/ mechanical properties is observed both for PLA and PCN5 subjected to reprocessing cycles. The crystallization rate of PLA is suppressed by the addition of clay, while is accelerated by clay after their processing. Additionally, the presence of clay is found to reduce the differences in the thermal stability between the samples reprocessed after 1 and 4 cycles, which is ascribed to the competition between intensive chain scission and better dispersion of clay in the PLA matrix.

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Section: Introductionmentioning

confidence: 99%

Multiscale analysis on multiextruded poly(lactic acid)/organoclay nanocomposites: Insights into the underlying mechanisms of thermomechanical degradation

Chen

et al. 2020

Polymers for Advanced Techs

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“…Therefore, the development of cost-effective and environmentally friendly methods to recover the properties of mechanically recycled PLA, and thus improve its recyclability, is a key challenge. In this regard, several alternatives have been proposed as valid approaches to increase the overall performance of recycled PLA, such as the use of thermal treatments [17], reactive extrusion with cross-linking agents and chain extender additives [18,19] and the use of inorganic fillers [3]. Furthermore, to guarantee the packaging green nature, another potential alternative is the utilization of reinforcements derived from renewable resources.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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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.

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“…Similarly, Morreale et al [ 11 ] observed no significant loss of mechanical properties in green composites from biopolymer matrix (Bioflex) and wood flour as a result of multiple processing cycles. Beltran et al [ 12 , 13 ] studied the reprocessing effect on the properties of postconsumer poly(lactic acid) (PLA) subjected to multiple extrusion cycles. The results showed that recycled PLA with good properties can be obtained by adding small amounts of additives during mechanical recycling.…”

Section: Introductionmentioning

confidence: 99%

Recycling of a Biodegradable Polymer Blend

et al. 2020

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Mechanical recycling is one of the possible ways to enhance the value of postconsumer plastic materials. However, the final performance of the recycled material will strongly depend on the quality of the selection made on the recycled product and on the degradation of the properties. In this context, the present study examines the effect of reprocessing for five successive extrusion cycles on the rheological, mechanical and thermal properties of a poly(butylene adipate-co-terephthalate) (PBAT)-based blend on samples reprocessed in both dry and wet conditions. The results showed that when the sample was processed after drying, degradation of the material was less than when it was processed in wet conditions. However, the experimental results showed that the decrease of rheological and mechanical properties was not so dramatic, and therefore the material could be reused in both cases.

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Mechanical recycling of poly(lactic acid): Evaluation of a chain extender and a peroxide as additives for upgrading the recycled plastic.

Cited by 70 publications

References 23 publications

Multiscale analysis on multiextruded poly(lactic acid)/organoclay nanocomposites: Insights into the underlying mechanisms of thermomechanical degradation

Multiscale analysis on multiextruded poly(lactic acid)/organoclay nanocomposites: Insights into the underlying mechanisms of thermomechanical degradation

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

Recycling of a Biodegradable Polymer Blend

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