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Polymer blends of poly(lactic acid) and starch for the production of films applied in food packaging: A brief review

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Polymers from Renewable Resources 2023年第2期14卷 108-153页

作者： Carneiro da Silva, Lucas Rafael Rios, Alessandro de Oliveira Campomanes Santana, Ruth Marlene Postgraduate Program in Mining Metallurgical and Materials Engineering Laboratory of Polymeric Materials Federal University of Rio Grande do Sul Rio Grande do Sul Brazil Postgraduate Program in Food Science and Technology Laboratory of Bioactive Compounds Federal University of Rio Grande do Sul Rio Grande do Sul Brazil

The limited degradation of synthetic polymers used in food packaging when discarded in the environment is a major concern for society. Therefore, industry and academia have sought to develop biodegradable and eco-friendly materials for single-use in packaging. An interesting alternative for the food industry is biodegradable polymeric films, which is why different biopolymers have been used in the production of sustainable packaging. It is worth mentioning that the use of biodegradable polymers is one of the most successful innovations in the industry to address issues related to the environment. Among the available raw materials, starch extracted from different renewable sources is very promising for this purpose, due to its abundance, low-cost compared to other polymers and ability to produce non-toxic films. However, when used alone, pure starch has many limitations, which can be overcome by developing a mixture with other polymers (polymer blends), preferably from renewable and biodegradable sources, such as poly(lactic acid) (PLA). In this context, the absence of literature reviews evidencing the results of the application of films in foods led us to write this article, given the importance of polymer blends produced with different types of starch (cassava, corn, pea, potato, rice and wheat) and the PLA matrix. According to the results, it is clear that polymer blends based on PLA/Starch for food packaging are very promising, already being part of the industries solutions, aiming to minimize the large volume of plastic waste of petrochemical origin discarded in nature. Obviously, as with any technology, more research is needed to further improve the performance of the films, and while much research has made great strides, there are still limitations that prevent the commercialization of these materials. © The Author(s) 2023.

关键词： Starch

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Valorization potential of coffee capsule waste: an updated bibliometric review

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Environmental science and Pollution Research 2025年第4期32卷 1681-1692页

作者： dos Santos, Wallan Azevedo Holanda, José Nilson F. Postgraduate Program in Materials Science and Engineering Darcy Ribeiro Northern Fluminense State University RJ Campos Dos Goytacazes City28013-602 Brazil Laboratory of Advanced Materials Darcy Ribeiro Northern Fluminense State University RJ Campos Dos Goytacazes City28013-602 Brazil

In recent years, coffee capsule waste has been generated on an increasingly large scale worldwide, but disposing of it in an environmentally sustainable and economical manner still poses major challenges. This work maps the original scientific production focused on the valorization of coffee capsule waste through a bibliometric review based on scientific articles published in the last 10 years (from 2014 to 2024) in the Scopus database. The review identified different ways of valuing coffee capsule waste, including the development of composite materials, composting, energy production, jewelry and decorative items, and the construction of supercapacitors and sensors. Some significant aspects were also emphasized: (i) this subject has a high potential for further growth;(ii) the published articles considered only part of the components of the coffee capsule waste;and (iii) most of the published articles were based on laboratory-scale experiments. Thus, the valorization of coffee capsule waste requires even more development. To address these challenges, manufacturers, consumers, researchers, governments, and the recycling industry should make a joint effort to develop innovative solutions that enable the complete valorization of coffee capsule waste in an environmentally friendly way. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Circular economy

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Impact Of WC Addition And High-Energy Milling Time On The Properties Of Cu-WC Composite Powders

Impact Of WC Addition And High-Energy Milling Time On The Pr...

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2024 European Powder Metallurgy Congress and Exhibition, Euro PM 2024

作者： Queiroz e Silva, Thalita Mashhadikarimi, Meysam Vieira, Pâmala Samara Marques, Anderson Costa Dos Santos Vasconcelos, Gabriel Dos Santos, Lucas Marques Materials Science and Engineering Postgraduate Program Federal University of Rio Grande do Norte Natal59078-970 Brazil School of Science and Technology Federal University of Rio Grande do Norte Natal59078-970 Brazil

ISBN: (纸本)9781899072583

Composites formed by a copper matrix, reinforced by a ceramic and refractory material, stand out due to their relevance in electrical conductor applications. In this context, this study investigated the hardening of copper powder with the addition of different concentrations of tungsten carbide (5, 10, 15 and 20% by weight) prepared by high-energy milling (HEM) for 1, 2, 5, 10 and 20 hours. The powders were characterized by SEM, XRD and Vickers microhardness. The results showed that the milling method was efficient for obtaining Cu-WC composites, with strong bonds between the phases. The diffractograms showed characteristic copper and tungsten carbide peaks, with no secondary phases. The Vickers microhardness value is directly related to the amount of WC and the milling time;consequently, the 20% WC composite powder milled for 20 hours had a microhardness of 251 HV, exceeding the values of the other powders. © European Powder Metallurgy Association (EPMA)

关键词： Microhardness

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Surface analysis of different wood polymer composites exposed to artificial weathering

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Journal of Wood Chemistry and Technology 2024年第2期44卷 88-101页

作者： Andrey Pereira Acosta Sandro Campos Amico Rafael de Avila Delucis André Luiz Missio Marlon Bender Bueno Rodrigues Ana Carolina Rodrigues Ribeiro Matheus de Paula Goularte Darci Alberto Gatto a PostGraduate Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul Porto Alegre Brazil b PostGraduate Program in Materials Science and Engineering Federal University of Pelotas Pelotas Brazil c Materials Engineering Undergraduate Course Federal University of Pelotas Pelotas Brazil

This study presents a superficial analysis of different wood polymer composites (WPC) comprising polystyrene (WPSC), poly(furfuryl alcohol) (WPFAC), and pine resin (WPRC) when exposed to artificial weathering. The study investigates the influence of resin type on the composites, focusing on their chemical, colorimetric, morphological, and thermal properties. The main findings indicate WPSC exhibits poor resistance to weathering, allowing ultraviolet radiation damage on the lignocellulosic component of the composite, leading to oxidized groups formation. Conversely, WPFAC and WPRC demonstrate good wood protection capabilities by preventing significant deterioration of holocellulose and acting as filters for radiation and moisture. Moreover, WPFAC exhibits the lowest decrease in carbonyl index and O/C ratio, with reductions of 2.6 and 11.6%, respectively. These findings are significant as they demonstrate that poly(furfuryl alcohol) and pine resin can be used to produce WPCs that delay and mitigate wood degradation by weathering, contributing to the increased potential utilization of *** AbstractDisplay full size

关键词： Chemical changes discoloration surface color UV degradation

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Effect of exposure to a light-emitting diode (LED) on the physicochemical characteristics of natural latex biomembranes used to treat diabetic ulcers

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Research on Biomedical engineering 2022年第3期38卷 901-911页

作者： Santana, Thamis Fernandes Oliveira, Rebeca Hannah de Melo dos Santos, Ludmila Evangelista Lima, Eunice Paloma Nascimento Faria, Sylvia de Sousa Fonseca, Marcos Augusto Moutinho da Silva, Jaqueline Rodrigues Tatmatsu-Rocha, José Carlos Gomes, Marília Miranda Forte Fleury Rosa, Mário Fabrício Fleury Rosa, Suélia de Siqueira Rodrigues Carneiro, Marcella Lemos Brettas Postgraduate Program in Biomedical Engineering University of Brasilia Federal District Brasilia Brazil Postgraduate Program in Materials Science and Engineering Federal University of Campina Grande Paraiba Campina Grande Brazil Department of Electrical Engineering University of Brasilia Federal District Brasilia Brazil Postgraduate Program in Biology Animal University of Brasilia Federal District Brasilia Brazil Medicine Faculty Physical Therapy Department Federal University of Ceara Ceara Fortaleza Brazil Postgraduate Technology and Health Program University of Brasília Federal District Brasília Brazil

Purpose: Natural latex biomembrane has shown high therapeutic potential for the treatment of diabetic ulcers when associated with phototherapy. In this study, physical and chemical alterations in the latex biomembranes were evaluated after exposure to light-emitting diode (LED) irradiation and after contact with NaCl solution. Methods: There were three experimental groups: natural latex biomembranes (1) in natura;(2) after 35 min of LED light irradiation;and (3) after immersion in NaCl 0.9 g% solution. The samples were analyzed by tensile strength test, thermogravimetry, contact angle wettability, and Fourier-transform infrared spectroscopy. Results: The biomembranes that were submitted to contact with NaCl aqueous solution or exposure to LED did not undergo impairment of mechanical resistance. The thermogravimetry analysis indicated that increasing temperature led to mass loss in all samples, referring to their decomposition temperatures. In the wettability test, biomembranes exposed to LED showed a significant reduction in the contact angle between 0 and 10 min, indicating an increase in hydrophilicity, suggesting water storage capacity. The Fourier-transform infrared spectrometry assay showed that there was a more significant reduction in vibration intensity after immersion in NaCl solution compared to untreated biomembranes. An increase in the intensity of the entire spectrum of biomembranes exposed to LED was observed in comparison with the other samples, which may be related to photodegradation caused by LED light irradiation. Conclusion: The biomembranes underwent significant changes in its chemical structure after being subjected to different types of exposure and maintained its elasticity and tensile strength properties, in addition to showing good water retention capacity after exposure to LED. Thus, it maintains many of its properties for application as a tissue-regenerating biomaterial, even when subjected to LED irradiation and a humid environment. © 20

关键词： Tissue regeneration

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Study Of The Influence Of Milling Time On The Synthesis Temperature Of Monoclinic And Orthorhombic Nanostructured Cunb2o6 Via High-Energy Milling

Study Of The Influence Of Milling Time On The Synthesis Temp...

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Euro Powder Metallurgy 2023 Congress and Exhibition, PM 2023

作者： Gomes, Uilame Umbelino de Araújo, Kívia Fabiana Galvão José, Maria Lima, Santos De Souza, Vitor Manoel Silva Fernandes da Silva Lourenço, Cléber Raimundo, Rafael Alexandre Materials Science and Engineering Postgraduate Program Federal University of Rio Grande do Norte Natal59078-970 Brazil Department of Physics Federal University of Paraíba João Pessoa58051-900 Brazil

Copper niobate (CuNb2O6) has been studied for technological and environmental applications, such as in solar cells and photocatalysts, for example. And to make the application of CuNb2O6 even more feasible, in this study, therefore, high-energy milling was applied in its synthesis process with variation in the milling time, from the precursor powders Nb2O5 and CuO. The calcination occurred in a muffle with temperatures in the range of 500 °C to 1000 °C, for 3 h and heating rate of 5 °/min. Then, the powders were characterized by XRD, SEM, EDS and Raman. The powders showed crystallite sizes smaller than 80 nm, good homogeneity and high purity. The particle morphologies and the Raman spectrum are coherent with the literature. It was also verified that the increase in milling time reduced the initial formation temperature of the monoclinic phase and the calcination time for the complete formation of the orthorhombic phase. © European Powder Metallurgy Association (EPMA)

关键词： Mechanical alloying

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Methane reforming reactions for hydrogen production using hydrotalcite precursors and nanofibers based catalysts 12

Methane reforming reactions for hydrogen production using hy...

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12th International Renewable Energy Congress, IREC 2021

作者： Silva, Thamyscira Chaghouri, Muriel Tidahy, Lucette Haingomalala Gennequin, Cedric Abi-Aad, Edmond Cesario, Moises MacEdo, Daniel Dunkerque France Federal University Of Paraiba Materials Science And Engineering Postgraduate Program Joao Pessoa Brazil

ISBN: (纸本)9781665432900

CoNiMg4Al2 catalysts were synthesized using two different methods: solution blow spinning to produce nanofibers (NF), and co-precipitation to produce hydrotalcite precursors (HT). Part of the hydrotalcite sample was ground (GR) using mechanical milling to determine the effect of grinding on the catalytic performance. The three materials (NF, HT and GR) were tested in the dry and steam reforming of methane (DRM, SRM respectively) reactions during 12h stability tests at 700°C. The calcined and the used catalysts were characterized using XRD and DTA/TG analysis. All catalysts were active during the SRM and DRM tests;however, nanofibers showed a slightly higher activity in both reactions. The dry reforming of methane reaction was more susceptible to the formation of carbon deposition leading to the deactivation of the ground catalyst. © 2021 IEEE.

关键词： Methane

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Thermo-optical properties of erbium-doped germanate-bismuth glasses

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Optical materials 2025年 166卷

作者： Silva, Adriano Almeida Lima, Lucas Batista Silva da Silva, Isis Lee Garcia, Hans Anderson Bell, Maria José Valenzuela Kassab, Luciana Reyes Pires Santos, Francisco Eroni Paz Postgraduate Program in Physics Federal University of Piauí PI 64049550 Brazil Department of Physics Federal University of Juiz de Fora MG Juiz de Fora36036-900 Brazil Faculdade de Tecnologia São Paulo CEETEPS SP São Paulo01124060 Brazil Postgraduate Program in Engineering and Materials Science Federal University of Teresina PI 64049550 Brazil

In this study, we investigate the thermo-optical properties of GeO2–Bi2O3 glasses doped with different concentrations of rare earth ions by thermal lens technique;UV-VIS and photoluminescence (PL) spectroscopy, as well as measurements of thermal diffusivity, thermal conductivity and quantum efficiency, are presented aiming at potential photonic applications. High infrared fluorescence lifetimes around 4 ms and quantum efficiencies of ∼80 % for 1 % Er3+ concentration, determined via lifetime and thermal lens methods, enabled efficient laser operation. Positive ds/dT values confirmed the self-focusing nature beneficial for high-power systems. While quantum efficiencies decreased exponentially with rising Er3+ due to non-radiative relaxation from erbium-matrix interactions, reasonably high efficiencies above 74 % persisted at 1 % doping. The thermal diffusivity and conductivity exhibited little changes with varying Er3+ concentration and showed to be matrix dependent. © 2025 Elsevier B.V.

关键词： Quantum efficiency

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Transient Ruddlesden-Popper-Type Defects and Their Influence on Grain Growth and Properties of Lithium Lanthanum Titanate Solid Electrolyte

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ACS Nano 2024年第16期18卷 10850-10862页

作者： Borštnar, Petruša Dražić, Goran Šala, Martin Lin, Che-An Lin, Shih-Kang Spreitzer, Matjaž Daneu, Nina Advanced Materials Department Jožef Stefan Institute Jamova cesta 39 Ljubljana1000 Slovenia Jožef Stefan International Postgraduate School Jamova cesta 39 Ljubljana1000 Slovenia Department of Materials Chemistry National Institute of Chemistry Hajdrihova 19 Ljubljana1000 Slovenia Department of Analytical Chemistry National Institute of Chemistry Hajdrihova19 Ljubljana1000 Slovenia Department of Materials Science and Engineering National Cheng Kung University Tainan70101 Taiwan Research Center National Cheng Kung University Tainan70101 Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan70101 Taiwan Core Facility Center National Cheng Kung University Tainan70101 Taiwan

Lithium lanthanum titanate (LLTO) perovskite is one of the most promising electrolytes for all-solid-state batteries, but its performance is limited by the presence of grain boundaries (GBs). The fraction of GBs can be significantly reduced by the preparation of coarse-grained LLTO ceramics. In this work, we describe an alternative approach to the fabrication of ceramics with large LLTO grains based on self-seeded grain growth. In compositions with the starting stoichiometry for the Li0.20La0.60TiO3 phase and with a high excess addition of Li (Li:La:Ti = 11:15:25), microstructure development starts with the formation of the layered RP-type Li2La2Ti3O10 phase. Grains with many RP-type defects initially develop into large platelets with thicknesses of up to 10 μm and lengths over 100 μm. Microstructure development continues with the crystallization of LLTO perovskite, epitaxially on the platelets and as smaller grains with thinner in-grain RP-lamellae. Theoretical calculations confirmed that the formation of RP-type sequences is energetically favored and precedes the formation of the LLTO perovskite phase. At around 1250 °C, the RP-type sequences become thermally unstable and gradually recrystallize to LLTO via the ionic exchange between the Li-rich RP-layers and the neighboring Ti and La layers as shown by quantitative HAADF-STEM. At higher sintering temperatures, LLTO grains become free of RP-type defects and the small grains recrystallize onto the large platelike seed grains via Ostwald ripening. The final microstructure is coarse-grained LLTO with total ionic conductivity in the range of 1 × 10-4 S/cm. © 2024 The Authors. Published by American Chemical Society.

关键词： Solid electrolytes

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Integrated Approachs for Calcination-Free Lithium Extraction from Beta-Spodumene and Synthesis of Lta-Type Zeolite: Experimental Insights and Computational Analysis

SSRN

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SSRN 2024年

作者： Dos Santos, Leonardo Leandro Do Nascimento, Rubens Maribondo Castellã Pergher, Sibele Berenice Department of Chemistry Federal University of Rio Grande do Norte Natal59078970 Brazil Postgraduate Program in Materials Science and Engineering Federal University of Rio Grande do Norte Natal59078970 Brazil

This study presents a novel approach to extract lithium from beta-spodumene and synthe- size LTA-type zeolite as a by-product, with no organic solvents or calcination. The process involves solubilization with sodium salts and the recycling of the mother liquor, with lithium content quantified via atomic absorption spectroscopy (AAS) from the supernatant. Syn- thesis conditions were carefully optimized to achieve the concurrent synthesis of LTA-type zeolite, denoted as LPM-15, characterized by cubic morphology and spherical facets. Com- putational simulations using density functional theory (DFT) were employed to investigate the impact of cation exchange processes (Na+/Al3+, NH4+/Al3+, and Ca2+/Al3+) on the stability of the LPM-15 structure and molecular diffusion within its zeolitic pores. Addi- tionally, the mobility of cations within the LPM-15 was assessed through cation exchange capacity (CEC) measurements. This comprehensive approach elucidates the fundamental mechanisms underlying LTA zeolite synthesis and provides valuable insights into potential applications, particularly in water purification. © 2024, The Authors. All rights reserved.

关键词： Density functional theory

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