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Effect of Concentration and Residence Time of Joncryl■ADR4368 on Melt Processability of Poly(3-hydroxybutyrate)

Journal of Renewable materials 2024年第12期12卷 2079-2094页

作者： Jéssica da Silva Chagas JoséElson Soares Filho Natália Fernanda Inocêncio Silva Marcelo Massayoshi Ueki Eliton Souto de Medeiros Renate Maria Ramos Wellen Mauricio Pinheiro de Oliveira Gelsoneide da Silva Gois Yêda Medeiros Bastos de Almeida Amélia S.F.Santos Post-Graduation Program in Materials Engineering(PPCEM) Federal University of Paraíba(UFPB)João PessoaPB 58051-900Brazil Laboratory of Materials and Biosystems(LAMAB) Federal University of Paraíba(UFPB)João PessoaPB 58051-900Brazil Department of Materials Engineering Federal University of Sergipe(UFS)Jardim Rosa ElzeSão CristóvãoSE 49100-000Brazil Institute of Science and Technology Federal University of São Paulo(UNIFESP)São Josédos CamposSP 12231-280Brazil Department of Chemical Engineering Federal University of Pernambuco(UFPE)Cidade UniversitáriaRecifePE 50670-901Brazil

Poly(3-hydroxybutyrate)(PHB)is a biothechnological and biodegradable thermoplastic polymer from the polyhydroxyalkanoates(PHAs)family,whose chain regularity,high molecular weight,and physical and mechanical properties comparable to polypropylene(PP)are characteristics that have made PHB a prominent commercial ***,its susceptibility to thermal degradation and hydrolysis has limited many *** address the challenges associated with processing,a random copolymer of 95.86 mol%3-hydroxybutyrate and 4.14 mol%3-hydroxyvalerate(referred as PHB)was compounded without(neat PHB)and with 0.25,0.5,1,and 1.5 wt%of chain extender(Joncryl■ADR 4368),consisting of multifunctional epoxy groups,and melt mixed in an internal mixer at 170℃,50 rpm,and residence times of 5,10,and 15 *** effect of chain extender concentration and residence time on the effectiveness of Joncryl■ADR 4368 to recover the pristine PHB properties were investigated through torque rheometry,melt flow index(MFI),differential scanning calorimetry(DSC),tensile testing,and thermogravimetric *** results indicated that an increase in residence time strongly influenced the prevalence of thermomechanical degradation reactions over chain extension reactions of PHB during processing in the molten *** residence times favored chain extension,while longer times favored chain *** trend led to no enhancement of PHB mechanical properties processed for 10 and 15 min,regardless of additive content *** flow index,thermogravimetric analysis and tensile strength exhibited an asymptotic behavior with the increase in additive concentration,exhibiting a noteworthy improvement in tensile strength and temperature at the highest rate of thermal degradation(TMAX),and a decrease in melt flow index of neat PHB with only 0.25 wt%of additive mixed for 5 *** results found in this work allow additional data for processing PHB by manipulating the ratios of multifunctional chain

关键词： PHB chain extender degradation epoxy groups viscosity

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CO2 Capture Using Silica-Immobilized Dicationic Ionic Liquids with Magnetic and Non-Magnetic Properties

SSRN

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SSRN 2024年

作者： Duarte, Evandro Bernard, Franciele Moreira Dos Santos, Leonardo Polesso, Bárbara B. Duczinski, Rafael Forneck, Vitor Geshev, Julian Einloft, Sandra Post-Graduation Program in Materials Engineering and Technology Pontifical Catholic University of Rio Grande do Sul – PUC RS Brazil School of Technology Pontifical Catholic University of Rio Grande do Sul – PUC RS Brazil Institute of Physics Federal University of Rio Grande do Sul RS Porto Alegre Brazil

The need to find alternative materials to replace aqueous amine solutions for CO2 capture in post-combustion technologies is pressing. This study assesses the CO2 sorption capacity and CO2/N2 selectivity of three dicationic ionic liquids with distinct anions immobilized in commercial mesoporous silica support (SBA-15). The samples were characterized by UART-FTIR, NMR, Raman, FESEM, TEM, TGA, Magnetometry (VSM), BET and BJH. The highest CO2 sorption capacity and CO2/N2 selectivity were obtained for sample SBA@DIL_2FeCl4 [at 1 bar and 25°C;57.31 (±0.02) mg CO2/g;12.27 (±0.72)]. The results were compared to pristine SBA-15 and revealed a similar sorption capacity, indicating that the IL has no impact on the silicás CO2 sorption capacity. On the other hand, the selectivity was improved by approximately 3.8, demonstrating the ionic liquid´s affinity for the CO2 molecule. The material underwent multiple sorption/desorption cycles and proved to be stable and a promising option for use in industrial CO2 capture processes. © 2024, The Authors. All rights reserved.

关键词： Carbon dioxide

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A Methodology for Obtaining and Validating Parameters for Surface Repairs Using the Pulsed Gmaw Process

SSRN

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SSRN 2023年

作者： Muñoz Chávez, Jairo José de Souza Lira, Margareth Nascimento Bestard, Guillermo Alvarez da Cruz Payão Filho, João Alfaro, Sadek Crisostomo Absi Post-Graduation Program in Mechatronics Engineering Department of Mechanical Engineering University of Brasilia CEP 70.910-900 Brazil Federal University of Rio de Janeiro Department of Metallurgical and Materials Engineering National Laboratory of Welding Technology Rio de Janeiro RJ Ilha do FundãoCEP 21941-972 Brazil

This study aims to develop a methodology for obtaining and validating surface parameters using the pulsed GMAW process, capable of producing a weld with appropriate geometric properties as a response. For this purpose, profiling was used as a capture tool together with stability analysis algorithms and metallic transfer criteria. The Fast Fourier Transform was used to analyze the intensity of electric current and voltage oscillogram for the delimitation of the most efficient pulse, detachment characteristics, and drop frequency in each analyzed parameter. In parallel, mathematical modelling of the overlapping of welding beads and volume filling simulation was carried out to obtain a repair methodology of satisfactory quality. Such strategies defined a working window with a voltage between 22 V and 28 V and an intensity of electric current between 190 A and 220 A. For the analyzed material, the best response values were at the base intensity of electric current of 80 A, base time of 1.47 ms, drop separator intensity of electric current of 110 A, drop separator time of 0.5 ms, the peak intensity of electric current of 375 A and peak time of 2.2 ms, corresponding to a working frequency of 240 Hz. With this work methodology, using signal analysis and profiling filming, it is possible to adapt the choice of process parameters to any material with energy and cost savings. These techniques are highly efficient and low-cost. In addition, the GMAW-P transfer mode allows quality work with the intensity of electric current values lower than conventional GMAW. © 2023, The Authors. All rights reserved.

关键词： Drops

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A New Class of Fillers in Mixed Matrix Membranes: Use of Synthetic Silico-Metallic Mineral Particles (Ssmmp) as a Highly Selective Component for Co2/N2 Separation

SSRN

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SSRN 2023年

作者： Ferrari, Henrique Z. Rodrigues, Daniela M. Bernard, Franciele L. dos Santos, Leonardo M. Le Roux, Christophe Micoud, Pierre Martin, François Einloft, Sandra Post-Graduation Program in Materials Engineering and Technology School of Technology Pontifical Catholic University of Rio Grande do Sul – PUCRS Brazil School of Technology Pontifical Catholic University of Rio Grande do Sul - PUCRS Porto Alegre Brazil Université de Toulouse ERT Géomatériaux Toulouse France

Membrane-based CO2 separation technology is a promising technology of low operating and energy costs and high scalability. This work describes the influence of synthetic silico-metallic mineral particles (SSMMP) and SSMMP/ionic liquids (IL) associated with polysulfone (PSF) to produce new mixed matrix membranes (MMM) for post-combustion technology. SSMMP is the precursor of synthetic talc undergoing no hydrothermal process resulting in a low-cost, energy-demanding, and CO2-free emission material due to its synthesis process. SSMMP have many reactive OH groups free on their surface making this material ideal to be compatibilized in a polymeric matrix. IL was immobilized in SSMMP to further improve CO2 affinity. As far as we know is the first time this material is used to obtain MMMs. MMMs were prepared with concentrations of 0.5, 1, 2 and 3 wt% of fillers via melting solution and solvent evaporation. The obtained MMMs were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) with elemental mapping, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Permeability analyzes were carried out at 25°C and 0.4MPa. The addition of pristine SSMMP and SSMMP/Im(nBu)Tf2N, improved membrane selectivity decreasing the permeability for the majority tested filler content. When using SSMMP/Im(nBu)I to obtain MMMs a different behavior was observed decreasing selectivity (except for MMM with 2% (w/w) of filler) and increasing permeability in all studied concentrations. The best result was obtained for sample SSMMP/Im(nBu)Tf2N (2%w/w) achieving a selectivity of 71.9, four times higher than pristine polysulfone membrane. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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Co2 Capture Using Silica-Immobilized Dicationic Ionic Liquids with Magnetic and Non-Magnetic Properties

SSRN

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SSRN 2023年

作者： Duarte, Evandro Bernard, Franciele Dos Santos, Leonardo Moreira Polesso, Bárbara B. Duczinski, Rafael Forneck, Vitor Geshev, Julian Einloft, Sandra Post-Graduation Program in Materials Engineering and Technology Pontifical Catholic University of Rio Grande do Sul – PUC RS Brazil School of Technology Pontifical Catholic University of Rio Grande do Sul – PUC RS Brazil Institute of Physics Federal University of Rio Grande do Sul RS Porto Alegre Brazil

关键词： Carbon dioxide

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Revolutionary valorization of carbon dioxide into dimethyl carbonate is catalyzed by sodium chloride: cheap, clean, one-pot, and water-free synthesis

arXiv

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arXiv 2023年

作者： Chaban, Vitaly V. Andreeva, Nadezhda A. Santos, Leonardo Moreira dos Einloft, Sandra Yerevan State University Yerevan0025 Armenia Peter the Great St. Petersburg Polytechnic University Saint Petersburg Russia School of Technology Pontifical Catholic University of Rio Grande do Sul - PUCRS Porto Alegre Brazil Post-Graduation Program in Materials Engineering and Technology School of Technology Pontifical Catholic University of Rio Grande do Sul – PUCRS Brazil

The robust valorization of carbon dioxide (CO2) stays at the center of sustainable development. Since CO2 represents a low-energy compound, its transformation into commercially coveted products is cumbersome. In the present work, we report a revolutionary method to obtain dimethyl carbonate (DMC) out of methanol (CH3OH) and CO2 catalyzed by sodium chloride (NaCl) and similar inorganic salts. The computational exploration revealed a mechanism of favorable catalysis, which was subsequently confirmed experimentally. Unlike all competitive syntheses of DMC, the new one does not produce water and, therefore, the hydrolysis of a carbonate does not occur. No dehydrating agents are necessary. The employed catalyst is cheap and permanently exists in the same phase with the reactants and products. The action of NaCl was compared to those of other alkali metal salts, LiI, LiCl, and KI, and competitive performances were recorded. The experimentally obtained result outperforms most competing technologies according to the DMC yield, 19% with molecular sieves and 17% without molecular sieves. All existing competitors are excelled by the simplicity and cleanness of the synthesis. The reported advance substantially simplifies the synthesis of linear organic carbonates and robustly valorizes CO2 © 2023, CC BY.

关键词： Methanol

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Influence of Phase Transformation Coefficient on Thermomechanical Modeling of Laser Powder Bed Fusion for Maraging 300 Steel

SSRN

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SSRN 2024年

作者： dos Santos Silva, Bruno Caetano de Figueiredo Soares, Lucas Coelho, Rodrigo Santiago Sitek, Wojciech Król, Mariusz Batalha, Gilmar Ferreira University Center SENAI CIMATEC SENAI Innovation Institute for Forming and Joining of Materials Av. Orlando Gomes 1845 Piata BA Salvador41650-010 Brazil Department of Mechatronics and Mechanical Systems Engineering Polytechnic School of Engineering University of Sao Paulo Av. Prof. Mello Moraes 2231 Butantã SP Sao Paulo05508-030 Brazil University Center SENAI CIMATEC Post-Graduation Program MPDS/GETEC/MCTI Av. Orlando Gomes 1845 Piata Salvador-BA41650-010 Brazil Department of Engineering Materials and Biomaterials Faculty of Mechanical Engineering Silesian University of Technology 18A Konarskiego St. Gliwice44-100 Poland

Manufacturing maraging steel components using laser-based powder bed fusion (LPBF) presents an attractive proposition for industries due to the material's combination of mechanical properties such as hardness, wear resistance, and toughness, and the capability to produce parts with complex geometries and high precision. Despite these advantages, the LPBF process induces defects such as distortion and residual stress associated with the complex thermal cycles, compromising final part quality. Numerical simulations have been developed to predict these defects. However, LPBF simulations remain challenging due to the complexity of the process and the substantial computational resources required. For maraging steel, for example, the occurrence of phase transformation promotes compressive stress that interferes in results and makes simulations inaccurate. This research aims to simulate a geometry with a circular inner channel and investigate distortion, volume fraction of martensite and equivalent stress results. Modeling was performed by varying phase transformation rate parameters to assess the impact of transformations on simulation outcomes. Results showed minimal impact of these parameters on distortions and equivalent stress. Equivalent stress results were compared with literature findings, while distortion results were validated against experimental data to validate the accuracy of the model. © 2024, The Authors. All rights reserved.

关键词： Phase transitions

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Theoretical insights into the chemical bonding, electronic structure, and spectroscopic properties of the lanarkite Pb2SO5 structure

arXiv

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arXiv 2023年

作者： Fabris, Guilherme S.L. Ferrer, Mateus M. Sambrano, Julio R. Almeida, Cláudio R.R. Paskocimas, Carlos A. La Porta, Felipe A. Graduate Program in Materials Science and Engineering Technological Development Center Universidade Federal de Pelotas RS Pelotas96010-610 Brazil Modeling and Molecular Simulation Group São Paulo State University Bauru São Paulo17033-360 Brazil Department of Materials Engineering Federal University of Rio Grande do Norte RN Natal59078-970 Brazil Postgraduate Program in Science and Engineering of Materials Federal University of Rio Grande do Norte RN Natal59078-970 Brazil Federal University of Technology - Paraná Nanotechnology and Computational Chemistry Laboratory Avenida dos Pioneiros 3131 CEP PR Londrina86036-370 Brazil State University of Londrina Post-Graduation Program in Chemistry Rodovia Celso Garcia Cid 445 km 380 CEP PR Londrina86057-970 Brazil

Lanarkite is a mineral formed by a combination of lead, sulphur, and oxygen atoms arranged in the general chemical formula Pb2SO5 (PSO) that crystallises with monoclinic symmetry (belonging to the C2/m space group, No. 12). This mineral was first discovered in Lanarkshire, Scotland and was named after its location. PSO has a unique structure comprising alternating penta-coordinated lead [PbO5] and tetra-coordinated sulphur [SO4] clusters. This lanarkite-type structure has recently attracted significant scientific interest and has been the focus of the superconducting material research community. However, its chemistry needs to be explored further. This article presents a comprehensive investigation on the chemical bonding, electronic structure, and spectroscopic properties of the lanarkite-type PSO structure from a computational perspective. Thus, different functionals in the DFT (e.g., PBE, PBE0, PBESOL, PBESOL0, BLYP, WC1LYP37, and B3LYP) were assessed to accurately predict their fundamental properties. All the DFT calculations were performed using a triple-zeta valence plus polarisation basis set. Among all the DFT functionals tested in this study, PBE showed the best agreement with the experimental data available in the literature. Our results also reveal that the [PbO5] clusters are formed with three Pb–O bond lengths, with values of about 2.32, 2.59, and 2.84 Å, respectively, while the [SO4] clusters have the same S–O bond length of 1.57 Å. We performed a complete topological analysis of this system to comprehend these structural differences. Additionally, the PSO structure has an indirect band gap energy of 2.9 eV and an effective mass ratio (mℎ∗ /me∗) of about 0.415 (using PBE calculations) which may, in principle, indicate a low recombination of electron-hole pairs in the lanarkite structure. Therefore, we believe that a detailed understanding of their electronic structures, spectroscopic properties as well as their chemical bonding is critically important

关键词： Lead compounds

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CO₂ sorption using encapsulated imidazolium-based fluorinated ionic liquids

引用

Environmental Challenges 2021年 4卷

作者： Bernard, Franciele L. Duarte, Evandro A. Polesso, Barbara B. Duczinski, Rafael B. Einloft, Sandra School of Technology Pontifical Catholic University of Rio Grande do Sul - PUCRS Porto Alegre Brazil Post-Graduation Program in Materials Engineering and Technology School of Technology Pontifical Catholic University of Rio Grande do Sul – PUCRS Brazil

The development and testing of new sorbents for the efficient removal of CO2 from flue gases is essential. Encapsulated room-temperature ionic liquids (RTILs) can be potentially employed in CO2 capture. In this work, ... 详细信息

The development and testing of new sorbents for the efficient removal of CO₂ from flue gases is essential. Encapsulated room-temperature ionic liquids (RTILs) can be potentially employed in CO₂ capture. In this work, we report the preparation and characterization of encapsulated imidazolium-based fluorinated RTILs for CO₂ capture. [Emim][TF₂N], [Bmim][TF₂N], and [Hmim][TF₂N] RTILS were encapsulated in polysulfone (PSF) using an emulsification method and characterized by several techniques. The pressure-decay technique was used to assess the CO₂ sorption capacity and reusability. Encapsulated RTILs showed improved utility for CO₂ capture processes compared with non-encapsulated RTILs, including higher CO₂ sorption capacity and faster CO₂ sorption/desorption. The CO₂ absorption/desorption cycles demonstrated the reuse capacity of all microcapsules under mild conditions. The highest CO₂ sorption capacity was noted for encapsulated [Emim][TF₂N] (39.5 mg CO₂ g⁻¹ at 298.15 K and 1 bar;62.7 mg CO₂ g⁻¹ at 298.15 K and 10 bar). It is worth emphasizing that the encapsulated [Emim][TF₂N] contained a lower ionic liquid (IL) content (37.5. ± 0.6) when compared to other encapsulated samples. Moreover, encapsulated [Emim][TF₂N] presented a higher CO₂ affinity than the encapsulated ILs reported in the literature. © 2021

关键词： CO2 capture Encapsulated ionic liquid Ionic liquid Microcapsules

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Special issue on membrane separation processes. A tribute to Professor Maria Norberta de Pinho

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Separation and Purification technology 2025年

作者： Alexandre Giacobbo Andréa Moura Bernardes Marco Antônio Siqueira Rodrigues Post-Graduation Program in Mining Metallurgical and Materials Engineering (PPGE3M) Federal University of Rio Grande do Sul (UFRGS) Av. Bento Gonçalves n. 9500 Porto Alegre 91509-900 Rio Grande do Sul Brazil Post-Graduation Program in Mining Metallurgical and Materials Engineering (PPGE3M) Federal University of Rio Grande do Sul (UFRGS) Av. Bento Gonçalves n. 9500 Porto Alegre 91509-900 Rio Grande do Sul Brazil Post-Graduation Program in Materials Technology and Industrial Processes Feevale University Rodovia RS-239 n. 2755 Vila Nova Novo Hamburgo 93525-075 Rio Grande do Sul Brazil

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