Influence of plasticizers on the compostability of polylactic acid

[EN] Poly(lactic acid) (PLA) has gained considerable attention as an interesting biobased and biodegradable polymer for film for food packaging applications, due to its many advantages such as biobased nature, high transparency and inherent biodegradable/compostable character. With the dual objective to improve PLA processing performance and to obtain flexible materials, plasticizer are use as strategy for extending PLA applications as compostable film for food packaging applications. Several plasticizers (i.e.: citrate esters, polyethylene glycol (PEG), oligomeric lactic acid (OLA), etc.) as well as essential oils and maleinized and/or epoxidized seed oils are widely used for flexible PLA film production. This article reviews the most relevant compostable PLA-plasticized flexible film formulations with an emphasis on plasticizer effect on the compostability rate of PLA polymeric matrix with the aim to get information of the possibility to use plasticized PLAbased formulatios as compostable films for sustainable industrial packaging production.M.P. Arrieta wants to thank Prof. Juan López-Martínez from Instituto de Tecnología de Materiales, Universitat Politècnica de València (EPSA-UPV, Spain) and Prof. José María Kenny from Civil and Environmental Engineering Department, Materials Engineering Centre, University of Perugia (UdR INSTM,, Italy), for their continuous support.Arrieta, MP. (2021). Influence of plasticizers on the compostability of polylactic acid. Journal of Applied Research in Technology & Engineering. 2(1):1-9. https://doi.org/10.4995/jarte.2021.14772OJS1921Abdelwahab, M.A., Flynn, A., Chiou, B.S., Imam, S., Orts, W., Chiellini, E. (2012). Thermal, mechanical and morphological characterization of plasticized PLA-PHB blends. Polymer Degradation and Stability, 97(9), 1822-1828. https://doi.org/10.1016/j.polymdegradstab.2012.05.036Agüero, A., Morcillo, M.C., Quiles-Carrillo, L., Balart, R., Boronat, T., Lascano, D.,... Fenollar, O. (2019). Study of the influence of the reprocessing cycles on the final properties of polylactide pieces obtained by injection molding. Polymers, 11(12), 1908. https://doi.org/10.3390/polym11121908Aragón-Gutierrez, A., Arrieta, M.P., López-González, M., Fernández-García, M., López, D. (2020). Hybrid Biocomposites Based on Poly (Lactic Acid) and Silica Aerogel for Food Packaging Applications. Materials, 13(21), 4910. https://doi.org/10.3390/ma13214910Arrieta, M.P., Fortunati, E., Dominici, F., López, J., Kenny, J.M. (2015). Bionanocomposite films based on plasticized PLA-PHB/cellulose nanocrystal blends. Carbohydrate Polymers, 121(0), 265-275. https://doi.org/10.1016/j.carbpol.2014.12.056Arrieta, M.P., Fortunati, E., Dominici, F., Rayón, E., López, J., Kenny, J.M. (2014a). Multifunctional PLA-PHB/cellulose nanocrystal films: Processing, structural and thermal properties. Carbohydrate Polymers, 107(0), 16-24.https://doi.org/10.1016/j.carbpol.2014.02.044Arrieta, M.P., Fortunati, E., Dominici, F., Rayón, E., López, J., Kenny, J.M. (2014b). PLA-PHB/cellulose based films: Mechanical, barrier and disintegration properties. Polymer Degradation and Stability, 107, 139-149. https://doi.org/10.1016/j.polymdegradstab.2014.05.010Arrieta, M.P., García, A.D., López, D., Fiori, S., Peponi, L. (2019). Antioxidant bilayers based on PHBV and plasticized electrospun PLA-PHB fibers encapsulating catechin. Nanomaterials, 9(3). https://doi.org/10.3390/nano9030346Arrieta, M.P., López, J., Hernández, A., Rayón, E. (2014). Ternary PLA-PHB-Limonene blends intended for biodegradable food packaging applications. European Polymer Journal, 50, 255-270. https://doi.org/10.1016/j.eurpolymj.2013.11.009Arrieta, M.P., López, J., López, D., Kenny, J.M., Peponi, L. (2016a). Biodegradable electrospun bionanocomposite fibers based on plasticized PLA-PHB blends reinforced with cellulose nanocrystals. Industrial Crops and Products, 93, 290- 301. https://doi.org/10.1016/j.indcrop.2015.12.058Arrieta, M.P., López, J., López, D., Kenny, J.M., Peponi, L. (2016b). Effect of chitosan and catechin addition on the structural, thermal, mechanical and disintegration properties of plasticized electrospun PLA-PHB biocomposites. Polymer Degradation and Stability, 132, 145-156. https://doi.org/10.1016/j.polymdegradstab.2016.02.027Arrieta, M.P., López, J., Rayón, E., Jiménez, A. (2014b). Disintegrability under composting conditions of plasticized PLAPHB blends. Polymer Degradation and Stability. https://doi.org/10.1016/j.polymdegradstab.2014.01.034Arrieta, M.P., Peponi, L. (2017). Polyurethane based on PLA and PCL incorporated with catechin: Structural, thermal and mechanical characterization. European Polymer Journal, 89, 174-184. https://doi.org/10.1016/j.eurpolymj.2017.02.028Arrieta, M.P., Peponi, L., López, D., Fernández-García, M. (2018). Recovery of yerba mate (Ilex paraguariensis) residue for the development of PLA-based bionanocomposite films. Industrial Crops and Products, 111, 317-328. https://doi.org/10.1016/j.indcrop.2017.10.042Arrieta, M.P., Perdiguero, M., Fiori, S., Kenny, J.M., Peponi, L. (2020). Biodegradable electrospun PLA-PHB fibers plasticized with oligomeric lactic acid. Polymer Degradation and Stability, 179. https://doi.org/10.1016/j.polymdegradstab.2020.109226Arrieta, M.P., Samper, M.D., Aldas, M., López, J. (2017). On the use of PLA-PHB blends for sustainable food packaging applications. Materials, 10(9), 1008. https://doi.org/10.3390/ma10091008Arrieta, M.P., Sessini, V., Peponi, L. (2017). Biodegradable poly(ester-urethane) incorporated with catechin with shape memory and antioxidant activity for food packaging. European Polymer Journal, 94, 111-124.https://doi.org/10.1016/j.eurpolymj.2017.06.047Auras, R.A., Harte, B., Selke, S., Hernandez, R. (2003). Mechanical, physical, and barrier properties of poly(lactide) films. Journal of Plastic Film and Sheeting, 19(2), 123-135. https://doi.org/10.1177/8756087903039702Auras, R., Harte, B., Selke, S.E. (2004). An overview of polylactides as packaging materials. Macromolecular Bioscience, 4(9), 835-864. https://doi.org/10.1002/mabi.200400043Balart, J., Montanes, N., Fombuena, V., Boronat, T., Sánchez-Nacher, L. (2018). Disintegration in compost conditions and water uptake of green composites from poly (lactic acid) and hazelnut shell flour. Journal of Polymers and the Environment, 26(2), 701-715. https://doi.org/10.1007/s10924-017-0988-3Beltrán, F.R., Arrieta, M.P., Gaspar, G., de la Orden, M.U., Urreaga, J.M. (2020). 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AN EXERGY COST ANALYSIS OF A COGENERATION PLANT

The exergy analysis, including the calculation of the unit exergetic cost of all flows of the cogeneration plant, was the main purpose of the thermoeconomic analysis of the STAG (STeam And Gas) combined cycle CHP (Combined Heat and Power) plant. The combined cycle cogeneration plant is composed of a GE10 gas turbine (11250 kW) coupled with a HRSG (Heat Recovery Steam Generator) and a condensing extraction steam turbine. The GateCycleTM Software was used for the modeling and simulation of the combined cycle CHP plant thermal scheme, and calculation of the thermodynamic properties of each flow (Mass Flow, Pressure, Temperature, Enthalpy). The entropy values for water and steam were obtained from the Steam Tab software while the entropy and exergy of the exhaust gases were calculated as instructed by. For the calculation of the unit exergetic cost was used the neguentropy and Structural Theory of Thermoeconomic. The GateCycleTM calculations results were exported to an Excel sheet to carry out the exergy analysis and the unit exergetic cost calculations with the thermoeconomic model that was created for matrix inversion solution. Several simulations were performed varying separately five important parameters: the Steam turbine exhaust pressure, the evaporator pinch point temperature, the steam turbine inlet temperature, Rankine cycle operating pressure and the stack gas temperature to determine their impact in the recovery cycle heat exchangers transfer area, power generation and unit exergetic cost

Supersolutions for a class of semilinear heat equations

A semilinear heat equation $u_{t}=\Delta u+f(u)$ with nonnegative initial data in a subset of $L^{1}(\Omega)$ is considered under the assumption that $f$ is nonnegative and nondecreasing and $\Omega\subseteq \R^{n}$. A simple technique for proving existence and regularity based on the existence of supersolutions is presented, then a method of construction of local and global supersolutions is proposed. This approach is applied to the model case $f(s)=s^{p}$, $\phi\in L^{q}(\Omega)$: new sufficient conditions for the existence of local and global classical solutions are derived in the critical and subcritical range of parameters. Some possible generalisations of the method to a broader class of equations are discussed.Comment: Expanded version of the previous submission arXiv:1111.0258v1. 14 page

Microstructure, mechanical, and thermogravimetric characterization of cellulosic by-products obtained from biomass seeds

The microstructural, thermal, and nanomechanical characterization of biomass by-products coming from the food industry were studied. Scanning electron microscopy showed a microstructure formed by polygonal grains. The thermal behavior of seeds, evaluated by thermogravimetric analysis, revealed three main components (hemicellulose, cellulose, and lignin). Walnut shell showed the highest thermal stability and also the highest amount of lignin. The nanomechanical aspects were evaluated by nanoindentation. Samples with higher amount of cellulose presented minor modulus values. In accordance with the thermal stability, the highest modulus and hardness were observed in walnut. These by-products could be useful as reinforcement materials for biodegradable plastic industry.This work has been supported by the Spanish Ministry of Science and Innovation (MAT2011-28468-C02-02) and the Autonomous Government of Valencia (Spain) through the research program Geronimo Forteza (62/2010, 9 de Junio DOCV no 6291). M.P. Arrieta is granted by Santiago Grisolia program (GRISOLIA/2011/007).Rayón Encinas, E.; Ferrándiz Bou, S.; Rico Beneito, MI.; López Martínez, J.; Arrieta, MP. (2015). Microstructure, mechanical, and thermogravimetric characterization of cellulosic by-products obtained from biomass seeds. International Journal of Food Properties. 18(6):1211-1222. https://doi.org/10.1080/10942912.2014.884578S1211122218

Utility of in vitro culture to the study of plant mitochondrial genome configuration and its dynamic features

Recombination activity plays an important role in the heteroplasmic and stoichiometric variation of plant mitochondrial genomes. Recent studies show that the nuclear gene MSH1 functions to suppress asymmetric recombination at 47 repeat pairs within the Arabidopsis mitochondrial genome. Two additional nuclear genes, RECA3 and OSB1, have also been shown to participate in the control of mitochondrial DNA exchange in Arabidopsis. Here, we demonstrate that repeat-mediated de novo recombination is enhanced in Arabidopsis and tobacco mitochondrial genomes following passage through tissue culture, which conditions the MSH1 and RECA3 suppressions. The mitochondrial DNA changes arising through in vitro culture in tobacco were reversible by plant regeneration, with correspondingly restored MSH1 transcript levels. For a growing number of plant species, mitochondrial genome sequence assembly has been complicated by insufficient information about recombinationally active repeat content. Our data suggest that passage through cell culture provides a rapid and effective means to decipher the dynamic features of a mitochondrial genome by comparative analysis of passaged and non-passaged mitochondrial DNA samples following next-generation sequencing and assembly

A Deeper Microscopic Study of the Interaction between Gum Rosin Derivatives and a Mater-Bi Type Bioplastic

[EN] The interaction between gum rosin and gum rosin derivatives with Mater-Bi type bioplastic, a biodegradable and compostable commercial bioplastic, were studied. Gum rosin and two pentaerythritol esters of gum rosin (Lurefor 125 resin and Unik Tack P100 resin) were assessed as sustainable compatibilizers for the components of Mater-Bi® NF 866 polymeric matrix. To study the influence of each additive in the polymeric matrix, each gum rosin-based additive was compounded in 15 wt % by melt-extrusion and further injection molding process. Then, the mechanical properties were assessed, and the tensile properties and impact resistance were determined. Microscopic analyses were carried out by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and atomic force microscopy with nanomechanical assessment (AFM-QNM). The oxygen barrier and wettability properties were also assayed. The study revealed that the commercial thermoplastic starch is mainly composed of three phases: A polybutylene adipate-co-terephthalate (PBAT) phase, an amorphous phase of thermoplastic starch (TPSa), and a semi-crystalline phase of thermoplastic starch (TPSc). The poor miscibility among the components of the Mater-Bi type bioplastic was confirmed. Finally, the formulations with the gum rosin and its derivatives showed an improvement of the miscibility and the solubility of the components depending on the additive usedThis research was funded by Spanish Ministry of Economy and Competitiveness (MINECO), project: PROMADEPCOL (MAT2017-84909-C2-2-R) and M.P.A. s contract: Juan de la Cierva-Incorporación (FJCI-2017-33536).Aldas-Carrasco, MF.; Rayón, E.; López-Martínez, J.; Arrieta, MP. (2020). A Deeper Microscopic Study of the Interaction between Gum Rosin Derivatives and a Mater-Bi Type Bioplastic. Polymers. 12(1):1-17. https://doi.org/10.3390/polym12010226S117121Keshavarz, T., & Roy, I. (2010). Polyhydroxyalkanoates: bioplastics with a green agenda. Current Opinion in Microbiology, 13(3), 321-326. doi:10.1016/j.mib.2010.02.006Aldas, M., Paladines, A., Valle, V., Pazmiño, M., & Quiroz, F. (2018). Effect of the Prodegradant-Additive Plastics Incorporated on the Polyethylene Recycling. International Journal of Polymer Science, 2018, 1-10. doi:10.1155/2018/2474176Arrieta, M. P., Peponi, L., López, D., & Fernández-García, M. (2018). Recovery of yerba mate (Ilex paraguariensis) residue for the development of PLA-based bionanocomposite films. Industrial Crops and Products, 111, 317-328. doi:10.1016/j.indcrop.2017.10.042Akrami, M., Ghasemi, I., Azizi, H., Karrabi, M., & Seyedabadi, M. (2016). A new approach in compatibilization of the poly(lactic acid)/thermoplastic starch (PLA/TPS) blends. Carbohydrate Polymers, 144, 254-262. doi:10.1016/j.carbpol.2016.02.035Elfehri Borchani, K., Carrot, C., & Jaziri, M. (2015). Biocomposites of Alfa fibers dispersed in the Mater-Bi® type bioplastic: Morphology, mechanical and thermal properties. Composites Part A: Applied Science and Manufacturing, 78, 371-379. doi:10.1016/j.compositesa.2015.08.023Sessini, V., Arrieta, M. P., Fernández-Torres, A., & Peponi, L. (2018). Humidity-activated shape memory effect on plasticized starch-based biomaterials. Carbohydrate Polymers, 179, 93-99. doi:10.1016/j.carbpol.2017.09.070Arrieta, M., Samper, M., Aldas, M., & López, J. (2017). On the Use of PLA-PHB Blends for Sustainable Food Packaging Applications. Materials, 10(9), 1008. doi:10.3390/ma10091008Aldas, M., Ferri, J. M., Lopez‐Martinez, J., Samper, M. D., & Arrieta, M. P. (2019). Effect of pine resin derivatives on the structural, thermal, and mechanical properties of Mater‐Bi type bioplastic. Journal of Applied Polymer Science, 137(4), 48236. doi:10.1002/app.48236Sessini, V., Navarro-Baena, I., Arrieta, M. P., Dominici, F., López, D., Torre, L., … Peponi, L. (2018). 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Interference of biodegradable plastics in the polypropylene recycling process

[EN] Recycling polymers is common due to the need to reduce the environmental impact of these materials. Polypropylene (PP) is one of the polymers called commodities polymers' and it is commonly used in a wide variety of short-term applications such as food packaging and agricultural products. That is why a large amount of PP residues that can be recycled are generated every year. However, the current increasing introduction of biodegradable polymers in the food packaging industry can negatively affect the properties of recycled PP if those kinds of plastics are disposed with traditional plastics. For this reason, the influence that generates small amounts of biodegradable polymers such as polylactic acid (PLA), polyhydroxybutyrate (PHB) and thermoplastic starch (TPS) in the recycled PP were analyzed in this work. Thus, recycled PP was blended with biodegradables polymers by melt extrusion followed by injection moulding process to simulate the industrial conditions. Then, the obtained materials were evaluated by studding the changes on the thermal and mechanical performance. The results revealed that the vicat softening temperature is negatively affected by the presence of biodegradable polymers in recycled PP. Meanwhile, the melt flow index was negatively affected for PLA and PHB added blends. The mechanical properties were affected when more than 5 wt.% of biodegradable polymers were present. Moreover, structural changes were detected when biodegradable polymers were added to the recycled PP by means of FTIR, because of the characteristic bands of the carbonyl group (between the band 1700-1800 cm(-1)) appeared due to the presence of PLA, PHB or TPS. Thus, low amounts (lower than 5 wt.%) of biodegradable polymers can be introduced in the recycled PP process without affecting the overall performance of the final material intended for several applications, such as food packaging, agricultural films for farming and crop protection.This research was funded by Conselleria d'Educacio, Investigacio, Cultura y Esport de la Generalitat Valenciana, grant number APOSTD/2018/209.Samper, M.; Bertomeu, D.; Arrieta, MP.; Ferri, JM.; López-Martínez, J. (2018). Interference of biodegradable plastics in the polypropylene recycling process. Materials. 11(10):1-18. https://doi.org/10.3390/ma11101886S1181110Plastics Europe, Plastics—The Facts 2017https://www.plasticseurope.org/application/files/5715/1717/4180/Plastics_the_facts_2017_FINAL_for_website_one_page.pdfAres, A., Bouza, R., Pardo, S. G., Abad, M. J., & Barral, L. (2010). Rheological, Mechanical and Thermal Behaviour of Wood Polymer Composites Based on Recycled Polypropylene. 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R., & Marconcini, J. M. (2016). Biodegradable Blends with Potential Use in Packaging: A Comparison of PLA/Chitosan and PLA/Cellulose Acetate Films. Journal of Polymers and the Environment, 24(4), 363-371. doi:10.1007/s10924-016-0785-4Avérous, L. (2004). Biodegradable Multiphase Systems Based on Plasticized Starch: A Review. Journal of Macromolecular Science, Part C: Polymer Reviews, 44(3), 231-274. doi:10.1081/mc-200029326Armentano, I., Fortunati, E., Burgos, N., Dominici, F., Luzi, F., Fiori, S., … Kenny, J. M. (2015). Processing and characterization of plasticized PLA/PHB blends for biodegradable multiphase systems. Express Polymer Letters, 9(7), 583-596. doi:10.3144/expresspolymlett.2015.55Arrieta, M. P., López, J., Rayón, E., & Jiménez, A. (2014). Disintegrability under composting conditions of plasticized PLA–PHB blends. Polymer Degradation and Stability, 108, 307-318. doi:10.1016/j.polymdegradstab.2014.01.034Garcia-Garcia, D., Ferri, J. M., Montanes, N., Lopez-Martinez, J., & Balart, R. (2016). Plasticization effects of epoxidized vegetable oils on mechanical properties of poly(3-hydroxybutyrate). Polymer International, 65(10), 1157-1164. doi:10.1002/pi.5164Russo, M. A. L., O’Sullivan, C., Rounsefell, B., Halley, P. J., Truss, R., & Clarke, W. P. (2009). The anaerobic degradability of thermoplastic starch: Polyvinyl alcohol blends: Potential biodegradable food packaging materials. Bioresource Technology, 100(5), 1705-1710. doi:10.1016/j.biortech.2008.09.026Neumann, I. A., Flores-Sahagun, T. H. S., & Ribeiro, A. M. (2017). Biodegradable poly (l-lactic acid) (PLLA) and PLLA-3-arm blend membranes: The use of PLLA-3-arm as a plasticizer. Polymer Testing, 60, 84-93. doi:10.1016/j.polymertesting.2017.03.013Khalid, S., Yu, L., Meng, L., Liu, H., Ali, A., & Chen, L. (2017). Poly(lactic acid)/starch composites: Effect of microstructure and morphology of starch granules on performance. 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Thermally-activated shape memory effect on biodegradable nanocomposites based on PLA/PCL blend reinforced with hydroxyapatite

[EN] In this work, the effect of the addition of different amount of nanosized hydroxyapatite (nHA) on the shape memory behavior of blends based on poly (lactic acid) (PLA) and poly (epsilon-caprolactone) (PCL) has been studied. In particular PLA/PCL blend with 70 wt % PLA has been reinforced with 0.5, 1 and 3 wt % nHA. Moreover, the relationship between the morphology and the final properties of the nanocomposites has been investigated by field emission scanning electron microscopy, confocal Raman spectroscopy and atomic force microscopy. In particular, PeakForce has been used to study quantitative nanomechanical properties of the multifunctional materials leading to conclusion that nHA increase the phase separation between PLA and PCL as well as act as reinforcements for the PCL-rich phase of the nanocomposites. Furthermore, excellent thermally-activated shape memory response has been obtained for all the nanocomposites at 55 degrees C. Finally, the disintegration under composting conditions at laboratory scale level was studied in order to confirm the biodegradable character of these nanocomposites. Indeed, these materials are able to be used for biomedical issues as well as for packaging applications where both thermally-activated shape memory effect and biodegradability are requested.Authors thank the Spanish Ministry of Economy, Industry and Competitiveness, MINEICO, (MAT2017-88123-P) and the Regional Government of Madrid (S2013/MIT-2862) for the economic support. M.P.A. and L.P. acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINEICO, respectively. The authors also thanks CSIC for the I-Link project (I-Link1149).Peponi, L.; Sessini, V.; Arrieta, MP.; Navarro-Baena, I.; Sonseca Olalla, Á.; Dominici, F.; Giménez Torres, E.... (2018). Thermally-activated shape memory effect on biodegradable nanocomposites based on PLA/PCL blend reinforced with hydroxyapatite. Polymer Degradation and Stability. 151:36-51. https://doi.org/10.1016/j.polymdegradstab.2018.02.019S365115

Innovative solutions and challenges to increase the use of poly(3-hydroxybutyrate) in food packaging and disposables

[EN] Poly(3-hydroxybutyrate) (PHB) has gain in recent years a huge interest in the food packaging field due to its renewable origin from waste as well as non-food crops, high mechanical strength, medium-to-high barrier performance, and inherent biodegradability in natural environments. Despite these advantages, PHB also shows a narrow processing window and high brittleness since this homopolyester shows low thermal stability and high crystallinity, limiting its industrial application. The present review provides an updated state of the art of the most relevant aspects in terms of processing and properties of PHB materials with a particular emphasis for their use in sustainable food packaging. It also describes the most potential strategies that can be applied to improve both the processability and mechanical properties of PHB, including the melt blending with green plasticizers and flexible biodegradable polymers as well as the development of more ductile co-polyesters. Finally, the waste management of the newly developed PHB-based articles is discussed, from their potential compostability to develop more biopolymers to more economically favored alternatives such as mechanical and chemical recycling technologies.This work was funded by the Spanish Ministry of Science and Innovation (MICINN, Spain), grant PID2021-123753NA-C32 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe", by the "European Union"; Comunidad de Madrid (Spain) by CIRCULAGROPLAST, a research Project that has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid; as well as by the Generalitat Valenciana (Spain) through the BEST Program (CIBEST/2021/94). S. Torres-Giner acknowledges the Spanish Ministry of Science and Innovation (MICINN, Spain) for his Ramón y Cajal contract (RYC2019-027784-I).Garcia-Garcia, D.; Quiles-Carrillo, L.; Balart, R.; Torres-Giner, S.; Arrieta, MP. (2022). Innovative solutions and challenges to increase the use of poly(3-hydroxybutyrate) in food packaging and disposables. European Polymer Journal. 178:1-20. https://doi.org/10.1016/j.eurpolymj.2022.11150512017