Jatorri berriztagarria duten zuntz zelulosikoz indarturiko polimero konpositeak

255 p.Azken urteetan, zenbait aplikazioetan erabiltzen diren material konposite sintetikoakordezkatzeko asmoz, biokonpositeak erabiltzeko interesa handitzen ari da. Hartaz,lanaren helburu nagusia jatorri berriztagarria duten material konpositeak prestatzeaeta ezaugarritzea izan da. Horretarako, sisal zuntzen gainazala eraldatu eta poli(azidolaktikoa) (PLA) polimeroan oinarritutako konpositeak prestatu dira. Jatorrizko PLAoso hauskorra dela ikusirik, jatorri ezberdineko landare olio mota ezberdinezplastifikatu da eta ondoren, alkali tratamenduaz eraldaturiko sisal zuntzez indartudira plastifikaturiko PLA matrizeak. Bestalde, almidoi termoplastikoa (TPS), matrizehidrofiloa prestatu eta landare zuntzetatik isolaturiko nanozelulosaz indartu da

Water Uptake Behavior and Young Modulus Prediction of Composites Based on Treated Sisal Fibers and Poly(Lactic Acid)

The main aim of this work was to study the effect of sisal fiber surface treatments on water uptake behavior of composites based on untreated and treated fibers. For this purpose, sisal fibers were treated with different chemical treatments. All surface treatments delayed the water absorption of fibers only for a short time of period. No significant differences were observed in water uptake profiles of composites based on fibers with different surface treatments. After water uptake period, tensile strength and Young modulus values of sisal fiber/poly(lactic acid) (PLA) composites were decreased. On the other hand, composites based on NaOH + silane treated fibers showed the lowest diffusion coefficient values, suggesting that this treatment seemed to be the most effective treatment to reduce water diffusion rate into the composites. Finally, Young modulus values of composites, before water uptake period, were predicted using different micromechanical models and were compared with experimental data.The authors are grateful for the financial support from the Basque Country Government in the frame of Consolidated Groups (IT-776-13) and Elkartek 2015 FORPLA3D project. Technical and human support provided by SGIker (Universidad del Pais Vasco-Euskal Herriko Unibertsitatea (UPV/EHU), Ministerio de Economia y Competitividad (MINECO), Gobierno Vasco-Eusko Jaurlaritza (GV/EJ), European Regional Development Fund (ERDF) and European Science Foundation (ESF)) is also gratefully acknowledged

Jatorri berriztagarria duten zuntz zelulosikoz indarturiko polimero konpositeak

255 p.Azken urteetan, zenbait aplikazioetan erabiltzen diren material konposite sintetikoakordezkatzeko asmoz, biokonpositeak erabiltzeko interesa handitzen ari da. Hartaz,lanaren helburu nagusia jatorri berriztagarria duten material konpositeak prestatzeaeta ezaugarritzea izan da. Horretarako, sisal zuntzen gainazala eraldatu eta poli(azidolaktikoa) (PLA) polimeroan oinarritutako konpositeak prestatu dira. Jatorrizko PLAoso hauskorra dela ikusirik, jatorri ezberdineko landare olio mota ezberdinezplastifikatu da eta ondoren, alkali tratamenduaz eraldaturiko sisal zuntzez indartudira plastifikaturiko PLA matrizeak. Bestalde, almidoi termoplastikoa (TPS), matrizehidrofiloa prestatu eta landare zuntzetatik isolaturiko nanozelulosaz indartu da

Biocomposites Based on Poly(Lactic Acid) Matrix and Reinforced with Lignocellulosic Fibers: The Effect of Fiber Type and Matrix Modification

in composite materials, two or more different components are combined to produce a new material with different characteristics from the individual components. In recent years, due to environmental concerns, the development of biocomposites based on natural fibers has attracted great interest of researchers. The mechanical properties of biocomposites are dependent, among other parameters, on matrix properties, fiber properties as well as fiber/matrix adhesion. There are different approaches to improve fiber/matrix adhesion, such as, the use of fiber surface treatments and the use of matrix modifiers, i.e.,: coupling agents. In this work, poly(lactic acid) matrix composites reinforced with two different lignocellulosic fibers (sisal and flax) were prepared and the mechanical properties of both types of composites were compared. On the other hand, poly(lactic acid) polymer was modified with maleic anhydride in the presence of dicumyl peroxide. The mechanical properties of PLA/lignocellulosic fiber composites modified with maleic anhydride-modified poly(lactic acid) were also studied.Authors are grateful for the financial support from the Basque Country Government in the frame of Elkartek “Provimat” KK-2018/00046 and PIBA19-0044 projects and from the University of the Basque Country in the frame of GIU 18/216 project. The authors also thank for technical and human support provided by SGIker of UPV/ EHU and European funding (ERDF and ESF). 6. Reference

Designing Spinel Li₄Ti₅O₁₂ Electrode as Anode Material for Poly(ethylene)oxide-Based Solid-State Batteries

The development of a promising Li metal solid-state battery (SSB) is currently hindered by the instability of Li metal during electrodeposition; which is the main cause of dendrite growth and cell failure at elevated currents. The replacement of Li metal anode by spinel Li4Ti5O12 (LTO) in SSBs would avoid such problems, endowing the battery with its excellent features such as long cycling performance, high safety and easy fabrication. In the present work, we provide an evaluation of the electrochemical properties of poly(ethylene)oxide (PEO)-based solid-state batteries using LTO as the active material. Electrode laminates have been developed and optimized using electronic conductive additives with different morphologies such as carbon black and multiwalled carbon nanotubes. The electrochemical performance of the electrodes was assessed on half-cells using a PEO-based solid electrolyte and a lithium metal anode. The optimized electrodes displayed an enhanced capability rate, delivering 150 mAh g−1 at C/2, and a stable lifespan over 140 cycles at C/20 with a capacity retention of 83%. Moreover, postmortem characterization did not evidence any morphological degradation of the components after ageing, highlighting the long-cycling feature of the LTO electrodes. The present results bring out the opportunity to build high-performance solid-state batteries using LTO as anode material

The Importance of Coupling Agent on Tensile and Thermomechanical Performance of Annealed Composites Based on Poly(Lactic Acid)/Poly(Methyl Methacrylate) Matrix and Sisal Fiber Bundles

The main aim of this work is to study the importance of the coupling agent on tensile and thermomechanical performance of annealed composites based on poly (lactic acid)/poly (methyl methacrylate) matrix and sisal fiber bundles. As coupling agent poly (styrene-co-glycidyl methacrylate) copolymer was used. Results obtained in the current study suggested that the presence of the copolymer is crucial to form a strong adhesion between the fibers and polymeric matrix and consequently to improve both thermomechanical performance and tensile properties after annealing process. It must highlight that the estimated heat deflection temperature (HDT) of annealed composite with 40 wt% of fiber increased around 40 ºC respect to respect to commercial neat PLA.This work was supported by the Eusko Jaurlaritza [KK-2018/00046]; Ministerio de Ciencia y Tecnología [PID2019-105090RB-I00

The Importance of Fiber/Matrix Adhesion and Annealing Process in Water Uptake of PLA/PMMA Matrix Composites Reinforced with Sisal Fibers: The Effect of Coupling Agent Addition

With the aim to open new applications possibilities to novel biocomposites based on PLA/PMMA matrix and reinforced with sisal fibers, it was studied the effect of water immersion aging on biocomposite tensile properties. In the current study it was evidenced the importance of the annealing process and fiber/matrix adhesion on the mechanical performance of composites after immersing in water for around 7 months. The presence of the copolymer and the annealing process led to the minor extent of damage of mechanical properties of prepared biocomposites. Results obtained in the current study suggested that although the amount of copolymer incorporated in composites was low, the presence of copolymer is crucial to improve fiber/matrix adhesion and consequently the mechanical performance of composites after immersing in water. It was observed that even though the water uptake damaged the interfacial adhesion, leading to the tensile strength reduction; however, annealed composite with 30 wt% of fiber and modified with the copolymer showed a strength value of around 53.5 MPa. It must highlighted that even though water aged for 7 months, the annealed composite with copolymer showed yet a higher strength value than dried commercial mineral-filled PP composites reported in the literature

Preparation and characterization of composites based on poly(lactic acid)/poly(methyl methacrylate) matrix and sisal fiber bundles: The effect of annealing process

The interest on poly(lactic acid) (PLA)/poly(methyl methacrylate) (PMMA) blends has increased during the last years due to their promising properties. The novelty of the current work focuses on the preparation and characterization of biocomposites based on PLA/PMMA matrix and NaOH-treated sisal fibers. The effect of the addition of treated sisal fibers on the physico-mechanical properties of high polylactide content composites was studied. For this purpose, PLA/PMMA blend (80/20 wt%) was prepared by melt-blending and reinforced with different fiber contents. Although composites showed interesting specific tensile properties, the estimated heat deflection temperature (HDT), that is, the maximum temperature at which a polymer system can be used as a rigid material, barely increased 4°C respect to unreinforced system. After the annealing process, the HDT of the unreinforced polymer blend increased around 25°C, whereas the composites showed an increase of at least 38°C. Nonetheless, the specific tensile strength of composite decreased approximately 48% because the adhesion between fiber and polymer matrix was damaged and cracks were formed during annealing process.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was financially supported by the Basque Country Government in the frame of Elkartek “Provimat” KK-2018/00046 and PIBA19-0044 projects

Enhancing the Performance of Ceramic-Rich Polymer Composite Electrolytes Using Polymer Grafted LLZO

Solid-state batteries are the holy grail for the next generation of automotive batteries. The development of solid-state batteries requires efficient electrolytes to improve the performance of the cells in terms of ionic conductivity, electrochemical stability, interfacial compatibility, and so on. These requirements call for the combined properties of ceramic and polymer electrolytes, making ceramic-rich polymer electrolytes a promising solution to be developed. Aligned with this aim, we have shown a surface modification of Ga substituted Li7La3Zr2O12 (LLZO), to be an essential strategy for the preparation of ceramic-rich electrolytes. Ceramic-rich polymer membranes with surface-modified LLZO show marked improvements in the performance, in terms of electrolyte physical and electrochemical properties, as well as coulombic efficiency, interfacial compatibility, and cyclability of solid-state cells

The effect of the carboxylation degree on cellulose nanofibers and waterborne polyurethane/cellulose nanofiber nanocomposites properties

[EN] There has been an exponential rise in the interest for waterborne polyurethanes (WBPU), due to the easy customizability of their properties and their ecofriendly nature. Moreover, their aqueous state facilitates the incorporation of hydrophilic reinforcements. Cellulose nanofibers (CNFs) have shown great potential, thanks to their renewability, large natural availability, low cost and great specific properties. However, CNFs often require some modification to obtain optimal compatibility. In this work, standard bleached hardwood kraft pulp has been subjected to a carboxylation process followed by mechanical disintegration. Varying treatment times and passes, CNF samples with different carboxylation degrees have been obtained. WBPU/CNF nanocomposites with different CNF content have been prepared. The effect of the carboxylation degree on the CNFs and on the nanocomposites properties has been studied. Although carboxylation damaged the cellulose structure, decreasing the crystallinity degree of CNF and reducing the thermal stability of fibers, composites showed better thermal and thermomechanical stability and improved mechanical properties than the unreinforced matrix counterpart. A maximum increase of 1670% in modulus, 377% in stress at yield and 86% in stress at break has been achieved for composites reinforced with carboxylated fibers. Therefore, it was observed that carboxylation improved matrix/ reinforcement interactions.Financial support from Basque Government (Grupos Consolidados IT776-13 and ELKARTEK (KK-2016/00043)), University of the Basque Country (GIU18-216 research group), Spanish Ministry of Economy, Industry and Competitiveness (MAT2016-76294-R) is acknowledged. We also wish to acknowledge the “Macrobehavior-Mesostructure-Nanotechnology” SGIker unit from the University of the Basque Country, for their technical support. I. L. thanks Basque Government for PhD Fellowship (PRE_2017_1_0085)