On the Recycling of a Biodegradable Polymer: Multiple Extrusion of Poly (Lactic Acid)

Gonçalves, Lívia M.G.; Rigolin, Talita Rocha; Frenhe, Bianca Maia; Bettini, Sílvia Helena Prado

doi:10.1590/1980-5373-mr-2020-0274

Cited by 17 publications

(10 citation statements)

References 24 publications

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“…In particular, the blends containing MLO cause the greatest yellowing in the samples. This index has a great advantage from the point of view of the packaging of certain elements, allowing better protection against light [69]. Colour coordinates L*a*b* were measured on injection-moulded samples.…”

Section: Colour Measurement and Wetting Properties Of Pla/sebs Blendsmentioning

confidence: 99%

Improvement of Impact Strength of Polylactide Blends with a Thermoplastic Elastomer Compatibilized with Biobased Maleinized Linseed Oil for Applications in Rigid Packaging

et al. 2021

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This research work reports the potential of maleinized linseed oil (MLO) as biobased compatibilizer in polylactide (PLA) and a thermoplastic elastomer, namely, polystyrene-b-(ethylene-ran-butylene)-b-styrene (SEBS) blends (PLA/SEBS), with improved impact strength for the packaging industry. The effects of MLO are compared with a conventional polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene-graft-maleic anhydride terpolymer (SEBS-g-MA) since it is widely used in these blends. Uncompatibilized and compatibilized PLA/SEBS blends can be manufactured by extrusion and then shaped into standard samples for further characterization by mechanical, thermal, morphological, dynamical-mechanical, wetting and colour standard tests. The obtained results indicate that the uncompatibilized PLA/SEBS blend containing 20 wt.% SEBS gives improved toughness (4.8 kJ/m2) compared to neat PLA (1.3 kJ/m2). Nevertheless, the same blend compatibilized with MLO leads to an increase in impact strength up to 6.1 kJ/m2, thus giving evidence of the potential of MLO to compete with other petroleum-derived compatibilizers to obtain tough PLA formulations. MLO also provides increased ductile properties, since neat PLA is a brittle polymer with an elongation at break of 7.4%, while its blend with 20 wt.% SEBS and MLO as compatibilizer offers an elongation at break of 50.2%, much higher than that provided by typical SEBS-g-MA compatibilizer (10.1%). MLO provides a slight decrease (about 3 °C lower) in the glass transition temperature (Tg) of the PLA-rich phase, thus showing some plasticization effects. Although MLO addition leads to some yellowing due to its intrinsic yellow colour, this can contribute to serving as a UV light barrier with interesting applications in the packaging industry. Therefore, MLO represents a cost-effective and sustainable solution to the use of conventional petroleum-derived compatibilizers.

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Section: Colour Measurement and Wetting Properties Of Pla/sebs Blendsmentioning

confidence: 99%

Improvement of Impact Strength of Polylactide Blends with a Thermoplastic Elastomer Compatibilized with Biobased Maleinized Linseed Oil for Applications in Rigid Packaging

et al. 2021

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“…Antagonistically, CH abundance in degraded PLA is connected with the recombination between macroradicals (R–CH • + • HC–R) generated by the Norrish type I mechanism. FTIR spectra do not show a significant variation of the OH infrared signal, indicating no PLA hydrolysis that generates secondary alcohols . The XPS results in Figure c indicate a slight increase of C–OH (secondary alcohol), suggesting that PLA also degrades by the Norrish type I mechanism with the etching time, following the FTIR results.…”

Section: Resultsmentioning

confidence: 71%

Antimicrobial Performance of Bioinspired PLA Fabricated via One-Step Plasma Etching with Silver and Copper

Silva

Rosa

2022

ACS Appl. Polym. Mater.

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Nanotechnology has been adopted to mimic a biological system to design artificial nanostructures with properties suitable for advanced applications. In this way, bioinspired bactericidal surfaces with surface nanostructured like insect wings display antimicrobial properties that undergo a physicomechanical mechanism that disrupts the microbial cells, inhibiting their growth and proliferation. Herein, we describe a method to design nanocone patterns on the surface of poly(lactic acid) (PLA) via one step of argon plasma etching in the presence of silver and copper. In this contribution, PLA with nanocone patterns were successfully obtained using 30 and 60 s of plasma etching, mimicking the surface of cicada wings that avoids the attachment of Escherichia coli, which is suitable for self-disinfectant medical devices. However, the plasma etching during 120 s generates a maze-like topographical surface with nanoholes that hampers both the adhesion and proliferation of bacteria on the PLA surface, which are important functional characteristics to fabricate self-disinfecting personal protection equipment for healthcare professionals in hospital environments subject to a wide variety of pathogenic microorganisms that adhere and proliferate on the material surfaces.

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“…In many cases, material degradation after multiple extrusion has also been considered for both single-screw extrusion and twin-screw extrusion. [8,11,[23][24][25][26][27][28][29][30][31][32][33] Here, among other factors, different screw speeds or screw configurations were investigated. Greater degradation was found with higher shear rates in the single-screw extruder [23] and with the increased use of kneading blocks on the twin-screw extruder.…”

Section: State Of the Artmentioning

confidence: 99%

Measurement of material degradation in dependence of shear rate, temperature, and residence time

Schall

Schöppner

2022

Polymer Engineering & Sci

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During processing, plastics are frequently exposed to high stresses. These include, above all, shear and temperature within the scope of the residence time of the manufacturing process in order to achieve a homogeneous plastic melt for further processing. The stress of the manufacturing process can lead to molecular degradation, which can have a negative effect on the product properties. Since it makes sense to take molecular degradation into account for many processes, a test stand for material characterization was designed and a regression equation was derived for the mathematical description of the degradation behavior. With the help of this regression equation, a prediction of the expected material degradation can be made, provided that the shear rate, the temperature and the associated residence time are known.

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On the Recycling of a Biodegradable Polymer: Multiple Extrusion of Poly (Lactic Acid)

Cited by 17 publications

References 24 publications

Improvement of Impact Strength of Polylactide Blends with a Thermoplastic Elastomer Compatibilized with Biobased Maleinized Linseed Oil for Applications in Rigid Packaging

Improvement of Impact Strength of Polylactide Blends with a Thermoplastic Elastomer Compatibilized with Biobased Maleinized Linseed Oil for Applications in Rigid Packaging

Antimicrobial Performance of Bioinspired PLA Fabricated via One-Step Plasma Etching with Silver and Copper

Measurement of material degradation in dependence of shear rate, temperature, and residence time

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