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The purpose of this study was to investigate the dry friction and wear behavior of WC-4.3 wt%MgO-2wt.%ZrO 2 (WM2Z) composite. WM2Z composite prepared by high-energy ball milling and spark plasma sintering (SPS) technology exhibited excellent comprehensive mechanical properties and dense microstructure. Dry friction test results indicated that the increase of sliding speed will lead to the decrease of friction coefficient, while at the same sliding speed, the extension of sliding time has no significant effect on the friction coefficient. The wear volume increased proportionally with the sliding time, while the wear rate stabilized after reaching a certain duration. The wear mechanism was mainly slight abrasive wear. Additionally, some oxidation occurred on both the WM2Z composite and the Si 3 N 4 ball during friction, forming an oxide film that contributed to the reduction of the friction coefficient. The novelty of this study lies in the first systematic investigation of the effects of sliding speed and time on the wear performance of WM2Z composite, and the revelation that in high-speed sliding environments, even with shorter sliding times, the material experiences faster wear. This discovery emphasizes the important role of sliding speed in the wear process and provides new insights into understanding the wear mechanism of materials in practical applications. This study not only enriches the friction and wear theory of binderless WC matrix composites, but also provides important experimental data and theoretical support for the design and application of related materials, laying a solid foundation for wear resistance optimization and industrial applications. [ABSTRACT FROM AUTHOR]

Ultrafine-grained binderless cemented carbides using 0.4 µm WC particles were prepared by adding Cr3C2, VC, TaC, βt and various sizes of Ti(C,N) particles. SEM observations of the polished and fractured surfaces revealed that the WC grains became finer after the addition of the carbides or carbonitrides. In the Ti(C,N)-added binderless cemented carbides, the WC grains became finer with decreasing Ti(C,N) particle size and increasing Ti(C,N) content. The grain size of WC in the binderless cemented carbide containing 0.1 μm Ti(C,N) was comparable to that of the Cr3C2-containing binderless cemented carbide, although not as fine as that of the VC-containing binderless cemented carbide. The binderless cemented carbides containing fine Ti(C,N) grains were harder and had higher strengths than the other carbides. The combined addition of fine Ti(C,N) and Cr3C2 resulted in more homogeneous WC grains. These results indicate that the grain growth inhibition of binderless cemented carbides varies depending on the type and grain size of the added carbonitrides. These findings will contribute to the future development of binderless cemented carbides. [ABSTRACT FROM AUTHOR]

Free formaldehyde is released due to the addition of aldehyde-based adhesives during the production of fiberboard. This is harmful to human health and pollutes the environment, and for that reason binderless fiberboard has become a research hotspot. There have been reports about pretreatments with white-rot fungi or lignocellulase to produce binderless fiberboard, but there have been no such reports about optimizing the bio-pretreatment conditions. In this study, poplar wood shavings were used for fiberboard production, and the bio-pretreatment conditions with Coriolus versicolor were studied using response surface methodology. After single-factor optimization, the central levels of bran, molasses, and magnesium sulfate were obtained. Further optimization was carried out using Box-Behnken design to study the influence of the factors. A second-order polynomial equation was obtained, and the low p-value (0.001) implied that the model was highly significant. The optimized bio-pretreatment conditions for modulus of rupture (MOR) of the fiberboard were obtained by ridge analysis as 3.021 g of bran, 8.907 g of molasses, and 0.27 g of magnesium sulfate. Under the optimized conditions, MOR of fiberboard reached 27.21±0.64 MPa, which was 2.2 times that of the control fiberboard. Bio-pretreatment with C. versicolor should be a good choice to produce a high-strength binderless fiberboard.

In this study, binderless WC ceramics with grain size of 210 nm were obtained under a high-pressure of 200 MPa at a relatively low temperature of 1550 °C. The effects of high pressure on the densification behavior and grain growth were investigated. Increasing the sintering pressure accelerated the densification rate, decreased the sintering temperature, and inhibited grain growth. HRTEM observations revealed highly stable Σ 2 grain boundaries and numerous microscopic defects (stacking faults and Lomer-Cottrell locks), with dislocation density up to 4.26×1015 m−2. High-pressure strengthening effect enhanced the hardness and wear resistance by inducing plastic deformation. The high-pressure sintered WC ceramics exhibited enhanced hardness of 32.19 GPa and excellent tribological properties. Compared with the low-pressure samples, the hardness increased by 23%, the friction coefficient reduced by 30%, and the wear resistance improved by 63%, which were mainly related to the fine-grained microstructure, stable Σ 2 grain boundaries, and high-density defects. [ABSTRACT FROM AUTHOR]

Sugarcane (Saccharum officinarum L.) leaf is an abundant waste from agriculture. In this study, we prepared binderless fiberboards from sugarcane leaf with <3 % moisture (w/w) and <1 mm in size by hot‐pressing temperature in the 210–240 °C range, followed by surface coating with polyurethane. The effect of hot‐pressing temperature on the modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) strength, and thickness swelling of the binderless sugarcane leaves was investigated. An optimal pressing condition for preparing the binderless sugarcane leaf fiberboards was 230 °C for pressing temperature, 5 MPa for pressing pressure, and 600 s for pressing time, giving 1200 kg m−3 for board density, MOE of 657.1 MPa, MOR of 7.04 MPa, and IB strength of 0.277 MPa. The thickness swelling of the coated samples was almost completely eliminated by the surface coating. [ABSTRACT FROM AUTHOR]

Biomass development has been a key issue for the past few decades and will remain attractive in the future because of its cleanliness, renewability, carbon neutrality, and other advantages. This study aims to determine the optimal holding time for heating system briquettes by testing the heating value of empty fruit bunches fibers. The process of this research involves the use of one unit of briquette molding equipment by providing a heating system to the mold cylinder. Fibers were manually finetuned until they reached a size of 20 mesh (0.84 mm). Densification temperature is an essential factor that could affect the combustion properties, especially the calorific value. The Arduino program is used for setting the heating resistance time of the mold, which is 15, 20, and 25 min at a temperature of 200 °C, and the thermal controller is used to adjust the temperature variation. Results showed that the highest calorific value of the three varieties of holding time was at 25 min with a calorific value of 4480.2 cal/g, and the lowest cost at 15 min was 4022 cal/g. Meanwhile, a calorific value of 4432.5 cal/g was found at 20 min. This finding is due to the low moisture content and high charcoal content of the sample in the 25 min briquette mold. Therefore, briquettes at 25 min have a higher heating value compared with those at 15 and 20 min holding time. [ABSTRACT FROM AUTHOR]

Flexible and binderless electrodes have become a promising candidate for the next generation of flexible power storage devices. However, developing high-performance electrode materials with high energy density and a long cycle life remains a serious challenge for sodium-ion batteries (SIBs). The main issue is the large volume change in electrode materials during the cycling processes, leading to rapid capacity decay for SIBs. In this study, flexible electrodes for a SnSb alloy–carbon nanofiber (SnSb@NC) membrane were successfully synthesized with the aid of hydrothermal, electrospinning and annealing processes. The as-prepared binderless SnSb@NC flexible anodes were investigated for the storage properties of SIBs at 500 °C, 600 °C and 700 °C (SnSb@NC-500, SnSb@NC-600 and SnSb@NC-700), respectively. And the flexible SnSb@NC-700 electrode displayed the preferable SIB performances, achieving 240 mAh/g after 100 cycles at 0.1 A g−1. In degree-dependent I-V curve measurements, the SnSb@NC-700 membrane exhibited almost the same current at different bending degrees of 0°, 45°, 90°, 120° and 175°, indicating the outstanding mechanical properties of the flexible binderless electrodes.

Flexible and binderless electrodes have become a promising candidate for the next generation of flexible power storage devices. However, developing high-performance electrode materials with high energy density and a long cycle life remains a serious challenge for sodium-ion batteries (SIBs). The main issue is the large volume change in electrode materials during the cycling processes, leading to rapid capacity decay for SIBs. In this study, flexible electrodes for a SnSb alloy–carbon nanofiber (SnSb@NC) membrane were successfully synthesized with the aid of hydrothermal, electrospinning and annealing processes. The as-prepared binderless SnSb@NC flexible anodes were investigated for the storage properties of SIBs at 500 °C, 600 °C and 700 °C (SnSb@NC-500, SnSb@NC-600 and SnSb@NC-700), respectively. And the flexible SnSb@NC-700 electrode displayed the preferable SIB performances, achieving 240 mAh/g after 100 cycles at 0.1 A g−1. In degree-dependent I-V curve measurements, the SnSb@NC-700 membrane exhibited almost the same current at different bending degrees of 0°, 45°, 90°, 120° and 175°, indicating the outstanding mechanical properties of the flexible binderless electrodes. [ABSTRACT FROM AUTHOR]

According to reported polymer-based magnetoelectric (ME) laminates, which generate voltage via an external magnetic field, a binder is indispensable for the adhesion between phases. However, if the binder is excluded, the ME response is expected to improve via efficient strain transfer from the magnetostrictive phase to the piezoelectric phase. Nevertheless, an understanding of the binderless state has not yet been addressed in polymer-based ME laminates. In this study, cellulose/Ni (CN) laminates were designed to obtain binderless polymer-based ME laminates. The surface properties of Ni foil desirable for the anchoring effect and the electrostatic interactions required for binderless states were determined via heat treatment of the Ni substrate. Moreover, to confirm the potential of the binderless laminate in ME applications, the ferromagnetic and ferroelectric properties of the CN laminates were recorded. Consequently, the CN laminates exhibited remnant and saturation magnetizations of 29.5 emu/g and 55.2 emu/g, respectively. Furthermore, the significantly increased remnant and saturation polarization of the CN laminates were determined to be 1.86 µC/cm2 and 0.378 µC/cm2, an increase of approximately 35-fold and 5.56-fold, respectively, compared with a neat cellulose film. The results indicate that multiferroic binderless CN laminates are excellent candidates for high-response ME applications. [ABSTRACT FROM AUTHOR]

We report a unique technique in forming an entangled carbon fibers without any glue material. We describe here a phenomenon where spraying aerosol of short carbon fibers realizes a spontaneous formation of a clump of entangled carbon fibers in few seconds. We named this method as a fiber aerosol deposition (FAD) method. We investigated the origin of this phenomena with comparing the length of the raw carbon fiber materials. We found that a range of the length distribution from 85 to 111 µm of the fibers is necessary to reproduce the phenomenon. Also found that the appearance of an intermediate state layer in initial formation stage enhances the fast development of the entangled carbon fibers. We point out that a clump of glue less short carbon fibers may be applicable for the recycling process of the wasted carbon fibers that are increasing in modern industry which utilizes the carbon fiber technology. [ABSTRACT FROM AUTHOR]

Indium oxide (In 2 O 3) anode material exhibits significant potential in lithium-ion batteries due to its low operating voltage and high theoretical specific capacity. However, its poor conductivity and substantial volume changes during Li+ insertion and extraction result in subpar rate performance and cycling stability. To address these issues, a binderless carbon-coated In 2 O 3 anode is constructed, utilizing foam nickel as the current collector and liquid nitrile rubber (LNBR-820H) with high adhesion as the carbon source. This approach enhances conductivity and mitigates volume expansion problems. The synergistic effects of carbon coating and binderless construction yield the In 2 O 3 @C10%-Ni-BL anode with an initial discharge specific capacity of 1052.43 mAh g−1, a discharge specific capacity of 513.60 mAh g−1 after 200 cycles, and improved rate performance. These findings demonstrate the viability of this synergistic strategy, which not only circumvents the negative impact of binders on conductivity and enhances Li+ insertion/extraction efficiency but also increases the proportion of active materials, thereby improving both rate performance and cycling stability of the anode. • A binderless carbon-coated In 2 O 3 anode is constructed. • This approach enhances conductivity and mitigates volume expansion problems. • The In 2 O 3 @C10%-Ni-BL anode displays high electrochemical performances. [ABSTRACT FROM AUTHOR]

Anode is a critical component in improving the performance of microbial fuel cells (MFC). Carbon nanotubes (CNTs) anodes of varying concentrations were employed to coat carbon felt (CF) using the dyeing method without the need of any binder agent. The anode's large and conductive electrode surface area enhances the flow of electrons from the yeast to the current collector and the adhesion/growth of the biofilm. Additionally, the enhanced bioelectrochemical activity was demonstrated by complete cell electrochemical measurements on the MFC using the synthesized anode. The CF/CNT2 electrode (4% w/v of CNT) is the optimum electrode because it produces MFC comparable performance to the CF/CNT3 electrode (6% w/v of CNT). Using CF/CNT2 electrodes, yeast MFC yields voltages and Maximum Power Densities (MPDs) of 0.255 ​V and 72.46 ​mW/m2, respectively. When compared to MFCs employing CF without any modification with CNTs, these outputs were roughly 40 and 436% higher, respectively. While the glucose on the MFC substrate decreases by 95.97 ​± ​0.14%, the conductive biofilm developing on the electrode surface increases by 255 ​± ​13 ​mg, which helps to boost electron transfer fairly nicely. That seems to be, the modified CF/CNT2 anode promoted the enrichment of electro-active microorganisms.

The adsorptive separation of CH4 from low‐grade coal‐bed gas can be performed at decentralized and remote coal mines, and it uses more energy‐ and is cost‐efficient than the traditional cryogenic distillation process. Herein, we present a facile method to prepare ultramicroporous carbon granules with a narrow pore‐size distribution at 0.5–0.6 nm. To our knowledge, such centered and uniform pore‐size distribution in carbon granules has never been reported. The carbon granules can be directly utilized in adsorption columns without a granulation or pelletization process. The granular oil‐tea‐shell‐derived porous carbon (GOC‐2) exhibited a record‐high CH4 uptake of 1.82 mmol/g and CH4/N2 selectivity of 5.8 at 1.0 bar and 298 K among carbon granules. The excellent CH4/N2 separation performances were confirmed from the results of dynamic breakthrough experiments and pressure swing adsorption simulations. This work provides a novel strategy for developing ultramicroporous carbon granules and guides the future design of efficient CH4/N2 separation adsorbents. [ABSTRACT FROM AUTHOR]

The utilization of agricultural and forestry residues for the development and preparation of green binderless fiberboard (BF) is an effective way to realize high-value utilization of lignocellulose biomass resources. This study focuses on the fabrication of BF with excellent mechanical and waterproof properties, utilizing poplar wood residue (PWR) as raw material and Trametes hirsuta as a pretreatment method. During the fermentation process, lignin-degrading enzymes and biological factors, such as sugars, were produced by T. hirsuta , which activated lignin by depolymerizing lignin bonds and modifying structural functional groups, and forming new covalent bonds between poplar fibers, ultimately enhancing adhesion. Additionally, the activated lignin molecules and sugar molecules coalesce under high temperatures and pressures, forming a dense carbonization layer that bolsters the mechanical properties of the fiberboard and effectively shields it from rapid water infiltration. The bio-pretreated BF for 10 days shows a MOR and MOE of up to 36.1 Mpa and 3704.3 Mpa, respectively, which is 261% and 247.8% higher than that of the bio-untreated fiberboard, and the water swelling ratio (WSR) rate is only 5.6%. Chemical composition analysis revealed that repolymerization occurred among lignin, cellulose, and hemicellulose, especially the molecular weight of lignin changed significantly, with the Mw of lignin increasing from 312066 g/mol to 892362 g/mol, and then decreasing to 825021 g/mol. Mn increased from 277790 g/mol to 316987.5 g/mol and then decreased to 283299.5 g/mol at 21 days. Compared to other artificial fiberboards prepared through microbial pretreatment, the BF prepared by microorganisms in this study exhibited the highest mechanical properties among the poplar wood biobased panels. [Display omitted] • A fungal pretreatment process was developed to fabricate eco-friendly and binderless fiberboards from poplar wood residue. • These fiberboards displayed superior mechanical properties compared to other microbial-pretreated boards. • Water swelling ratio of 5.6% was significantly lower than other wood-based fiberboards. [ABSTRACT FROM AUTHOR]

Abstract Rice straw is a troublesome biomass for an industrial application because of its high silica content and the wax-like substances covering the surface. At manufacturing binderless boards, which are considered environmentally friendly as they do not contain synthetic resins, rice straw silica contributed to water resistance, while the wax-like substances adversely affected self-bonding. This study investigated the effects of steam treatment on the self-bonding of binderless boards manufactured from rice straw. The chemical changes during steam treatment were examined by gas chromatography–mass spectrometry (GC–MS), and their influence on the bonding properties is discussed. Internal bonding strength and water resistance significantly increased by steam treatment. They also increased with increasing pressing temperature, and decreasing particle size. GC/MS analysis showed that not only hemicellulose and lignin, but also amorphous cellulose was decomposed during the steam treatment. Among the degradation products, 5-hydroxymethylfurfural was suggested to contribute to self-bonding during hot-pressing, while furfural was vaporized from the rice straw. Fine-grinding to below 150 μm after steam treatment resulted in high water resistance and an internal bonding strength of 0.6 MPa, which met the Japan Industrial Standards (JIS) requirement for Type-30 medium-density fiberboard (MDF). This mild pretreatment offers an alternative to steam explosion.

Binderless poplar powder compacts were prepared using the hot-pressing technology. The effect of the forming process on the mechanical properties and surface color of the poplar powder compacts was studied. The effect of forming temperature on mechanical properties and surface color was more noticeable than the forming pressure and the holding time. With the change of the forming process parameters, the static bending strength of the compacts increased first and then decreased. The overall change trend of the surface hardness increased continuously. The overall color difference (ΔE*) of the compacts increased with the change of forming process parameters and the surface color deepened gradually. The results of Fourier transform infrared (FTIR) spectroscopy showed that hemicellulose, cellulose, and lignin in the compacts were greatly affected by the forming process parameters. The degradation of hemicellulose and cellulose produced many colored substances, and the content of lignin increased. These made the surface color of compacts deepen. [ABSTRACT FROM AUTHOR]

High-temperature oxidation tests were carried out on binderless tungsten carbide (WC) with different Y2O3 contents (0, 1, 2, 3, and 4 wt.%) and on YG3 cemented carbide. Results demonstrated that the addition of Y2O3 led to a significant improvement in the high-temperature oxidation resistance of binderless tungsten carbide compared with those of YG3 cemented carbide and pure tungsten carbide. After oxidation at 800°C for 120 min, the oxidation weight gain of binderless tungsten carbide with 1 wt.% Y2O3 was 58.54 mg cm−2, corresponding to the reduction by 47.7% compared with YG3 cemented carbide. In the high temperature oxidation process, WC in the triangle grain boundary was first oxidized to Y2WO6 due to the high activity of Y2O3 which is present mainly in the WC grain boundaries. The transport of W4+ outward along the grain boundary and the diffusion of O2− inward along the grain boundary were hindered by Y2WO6 with the high ionic radius and thus the antioxidant capacity of binderless tungsten carbide was improved. Meanwhile, the adhesive ability of oxidation layer on the substrate was enhanced with the “pinning effect” of Y2WO6, which also led to the improvement of oxidation resistance. With the Y2O3 content increasing from 1 to 4 wt.%, the antioxidant properties of binderless tungsten carbide gradually declined, and the antioxidant performance of binderless tungsten carbide with 1 wt.% Y2O3 was found to be the best.

Binderless cemented carbide contains very little (

In this paper, a two-step, solution-based method and post-calcination were employed to coat NiCo2O4 nanowires arrays onto dense SnO2 thin films which were grown on Ni foam substrates. Owing to the low charge transfer resistance and good electronic conductivity of the SnO2 thin films, the specific SnO2 thin films were used as the supporting backbone. X-ray diffraction and elemental mapping were applied to demonstrate the existence of Ni, Co, O, Sn while the hierarchical structure and morphology of SnO2@NiCo2O4 were analyzed by field emission scanning electron microscopy. The electrochemical performance of SnO2@NiCo2O4 was also investigated in a three-electrode system. The as-formed SnO2@NiCo2O4 electrode had outstanding electrochemical performance (1.49 F cm−2 at 1 mA cm−2) and good cycling stability (retaining 86% after 2000 cycles). On the one hand, the excellent pseudocapacitive performance was mainly due to the addition of the SnO2 thin films, which served as a conducting oxide thin film to provide low charge transfer resistance. On the other hand, the SnO2 thin films offered a more effective place for the growth of NiCo2O4 nanowires arrays than the bare Ni foam substrates. The perfect electrochemical performance of these hybrid nanomaterials showed their potential in supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

Rice straw is a troublesome biomass for an industrial application because of its high silica content and the wax-like substances covering the surface. At manufacturing binderless boards, which are considered environmentally friendly as they do not contain synthetic resins, rice straw silica contributed to water resistance, while the wax-like substances adversely affected self-bonding. This study investigated the effects of steam treatment on the self-bonding of binderless boards manufactured from rice straw. The chemical changes during steam treatment were examined by gas chromatography–mass spectrometry (GC–MS), and their influence on the bonding properties is discussed. Internal bonding strength and water resistance significantly increased by steam treatment. They also increased with increasing pressing temperature, and decreasing particle size. GC/MS analysis showed that not only hemicellulose and lignin, but also amorphous cellulose was decomposed during the steam treatment. Among the degradation products, 5-hydroxymethylfurfural was suggested to contribute to self-bonding during hot-pressing, while furfural was vaporized from the rice straw. Fine-grinding to below 150 μm after steam treatment resulted in high water resistance and an internal bonding strength of 0.6 MPa, which met the Japan Industrial Standards (JIS) requirement for Type-30 medium-density fiberboard (MDF). This mild pretreatment offers an alternative to steam explosion. [ABSTRACT FROM AUTHOR]

We report a simple strategy to fabricate electrodes for high temperature electrolyte membrane fuel cell (HT-PEMFC) by eliminating binder. The Electrophoretic Deposition (EPD) method was used to fabricate the Gas Diffusion Electrode (GDE) in the absence of the binder. For comparison, the same catalyst ink was used to make hand-spray binderless electrode, and both electrodes used as anodes for Membrane Electrode Assemblies (MEAs) in a HT-PEMFC operating at 140°C. XRD and SEM were used to investigate the microstructure and morphology of GDEs. The ECSA was studied, and CO oxidation and desorption were evaluated. Results indicated proper attachment of electrocatalyst on GDL and better results for CO oxidation and desorption, when binderless EPD method was used. The maximum power density 180 mW cm−2 was obtained for MEA prepared by binderless EPD method. Comparing these results by other works indicate that the binderless EPD electrode could be utilised as the anode for HT-PEMFC. [ABSTRACT FROM AUTHOR]

Highlights • Activated carbon monoliths from olive stone and lignins were obtained without binder. • Carbon monoliths with 25 or 120 channels/cm2 were prepared in a home-made extruder. • A stabilization step was optimized to reduce the plasticity and swelling of lignin. • Alcell lignin monolith shows relatively high specific capacitance 205 F/g. Abstract The valorization of lignocellulosic biomass waste into bio-based materials is proposed in this work in order to obtain low-cost materials and to reduce environmental impacts. Cylindrical activated carbon monoliths (ACMs) were prepared from Alcell®, Kraft lignin and olive stone by chemical activation with H 3 PO 4. To our best knowledge, there is no previous information about the preparation of ACMs from any type of lignin. In this sense, the development of value-added lignin-based products could be crucial to the economic success of the bio-ethanol production within a biorefinery context. The extrusion of the adequate mixing, without any kind of binder, was carried out in an extruder designed by ourselves with different dies. Carbon monoliths without and with holes (25 or 120 channels/cm2) were obtained. In case of lignin precursors, a stabilization step was optimized to minimize the problems of plasticity and swelling of lignin. N 2 adsorption–desorption at −196 °C and Hg porosimetry results show that activated carbon monoliths presented pore size distributions in the micro and mesopore range, with high surfaces areas (c.a. 1500 m2/g) and relatively high mesopore volume (0.35 cm3/g). The bulk density of the monoliths is also very high (∼1.1 g/cm3 for ACM from Alcell lignin), with compressive strength of 7.6 MPa. Electrochemical characterization of binderless activated carbon monolith electrodes was carried out by cyclic voltammetry and galvanostatic charge–discharge techniques. The ACM from olive stones presents the highest specific capacitance, with approximately 217 F/g and 205 F/cm3. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract Palm empty fruit bunch (EFB) has a high potential to be utilized as energy source in Indonesia. However, due to some of its properties such as low bulk density, low hydrophobicity, high moisture content, high chlorine and alkaline content, pretreatment of EFB is required before it can be utilized as fuel. This study examined the effects of hydrothermal treatment and pelleting temperature on physical characteristics of EFB pellets. EFB was hydrothermally treated using 10m3 batch type reactor and water leached using centrifugal machine. Single pellet making device was used for densification of both treated and untreated EFB. Pellets were compacted at a pressure of 60 MPa and temperature of 100, 150 and 200 °C. Pellet density, compressive strength and durability of each pellets were evaluated. Results indicated that combination of hydrothermal treatment and water leaching significantly improved pelletization performance of EFB especially when it was pelletized at 100 °C. At pelleting temperature of 100 °C, pellet durability index (PDI) and compressive strength of EFB increased from 78.1% and 2.85 MPa to 98.72% and 7.80 MPa respectively when it was hydrothermally treated. Notable increase in pellet properties of untreated EFB were also observed as pelletizing temperature increase. At pelleting temperature of 200 °C, PDI and compressive strength increased to 92.83% and 7.09 MPa respectively. However, only slight improvement in characteristics of the washed hydrochar pellets were observed as the pelletizing temperature increased. [ABSTRACT FROM AUTHOR]

This paper explores the possibility of producing all-lignocellulosic fiberboards from Arundo donax L. as a source of lignocellulosic fibers with no synthetic binders. This raw material was steam exploded with a thermomechanical aqueous vapor process in a batch reactor. The Arundo donax raw material and its obtained pulp were characterized in terms of chemical composition and the results were compared to other lignocellulosic materials. The chemical composition of steam exploded Arundo fibers showed high cellulose and a moderate lignin content suggesting it was a good raw material for fiberboard production. The all-lignocellulosic fiberboards were produced on laboratory scale; using the steam exploded Arundo donax by means of a wet process. The effects of pressing pressure on physical and mechanical properties were evaluated and the conditions that optimize the responses were found. The analyzed properties were density (d); water absorption (WA); thickness swelling (TS); modulus of elasticity (MOE); modulus of rupture (MOR); and internal bond strength (IB). The tested levels of the pressing pressure range from 0.35 to 15 MPa. The optimum IB; MOE; MOR; WA and TS were 1.28 MPa, 7439 MPa, 40.4 MPa, 17.6% and 13.3%, respectively. The obtained fiberboards were of very good quality and more than satisfy the requirements of the relevant standard specifications. [ABSTRACT FROM AUTHOR]

As the worldwide demand for fuels and materials increases, fossil resources are decreasing and global warming is a concern, and thus the need for alternative solutions is high. In the industries of furniture and housing, particleboards are interesting materials, as they reutilize wastes from other industries (wood, agriculture) although they also rely on chemical binders that are petroleum-based and toxic. A very promising alternative is then clearly identified in finding ways to produce binderless boards and associated materials. This review considers the state of the art in the field of binderless board production, and other processes making it possible to turn raw plant fibers into structural materials without using any external chemistry. The mechanical properties and water resistance are collected and compared. Identified chemistry changes occurring during the thermo-compressive process are discussed with an aim towards understanding of the mechanisms of cohesion.

The aim of this study was to produce dense, single phase polycrystals. The research was carried out on the submicron tungsten carbide powder without additives, with either a carbon or tungsten additive and on the powder with both additives. The primary task of carbon was to reduce surface oxide impurities which passivate WC grains; tungsten in turn bounds free carbon in the WC. The authors manufactured fine-grained, dense (96–98% T.D.) and single-phase WC polycrystals, using the technique of pressureless sintering at the temperature not exceeding 2000 °C. A positive effect of carbon addition on tungsten carbide sinterability was observed, whereby a dense, fine-grained polycrystals can be obtained at 1900 °C. It was also observed that a significant excess of temperature of sintering process resulted in a strong abnormal grain growth of WC grains. [ABSTRACT FROM AUTHOR]

Wet-formed particleboard panels were made using cellulose nanofibrils (CNF) as the bonding material. The effects of panel density, CNF addition ratio, particle size, and pressing method on the nail and face screw withdrawal strength, water absorption (WA), and thickness swelling (TS) were investigated. The nail and face screw withdrawal strength increased with an increased panel density and CNF addition ratio. Mixed-size particles were favorable for better face screw withdrawal strength. The WA decreased while TS increased with increased panel density. The WA decreased with increased CNF addition ratio. The effect of CNF addition ratio on the TS was influenced by an interaction effect of the particle size, density, and pressing method. Smaller wood particles and the constant thickness (CT) pressing method were better for both WA and TS performance. All of the high- and medium-density panels failed to satisfy the standard requirements for face screw withdrawal strength. For lowdensity panels, those manufactured with mixed-sized particles all satisfied the standard requirements; those manufactured with large particles required at least 15% CNF to meet the standard, and those manufactured with small particles required at least 20% CNF to achieve the standard requirements. None of the panels met the standard TS requirement (< 8%). [ABSTRACT FROM AUTHOR]

Wet-formed particleboard bonded with cellulose nanofibrils (CNF) was prepared in this work. The effects of density, CNF addition ratio, pressing method, and particle size on the bending strength were evaluated. The results showed that density had the most important effect on the modulus of elasticity (MOE), while the CNF addition ratio had the most important effect on the modulus of rupture (MOR). For panels with low density (< 640 kg/m3), the MOE and MOR did not change much with the configuration changes between particle size and pressing method. This was due to the synergistic effect of incomplete compression and poor bonding in the core area using a constant thickness (CT) pressing method, and lower face density and higher core density using a constant pressure (CP) pressing method. For panels with medium density (640 kg/m3 to 800 kg/m3), the combination of larger particles, higher CNF addition ratio, and CT pressing method contributed to the highest bending strength. Further increase to high density (> 800 kg/m3), the pressing method's effect was more important, compared to panels with low and medium densities. With increased density and CNF addition ratio, panels were able to meet lowdensity and some medium-density standard MOE and MOR requirements. [ABSTRACT FROM AUTHOR]

We report the combined experimental and theoretical investigations on high pressure structural stability of niobium carbide (NbC). The compressibility of NbC has been measured using angle-dispersive synchrotron X-ray diffraction in a diamond anvil cell (DAC) at room temperature and high pressure (up to 38.0 GPa), complemented with first-principles density-function theory calculations. The results imply that NbC shows bulk modulus of = 281 (6) GPa with a pressure derivative = 6.2 (1.5) for its strong covalent bonding. In addition, indentation testing on the well-sintered bulk NbC obtained at 5.0 GPa/1400°C yielded a Vickers hardness of 19.2 GPa and fracture toughness of 7.7 MPa m1/2at applied load of 10 kgf, demonstrating that binderless NbC prepared under high pressure should be a prospective hard material. [ABSTRACT FROM PUBLISHER]

The objective of the study was to investigate physical and mechanical properties of experimental particleboard panels manufactured from oil palm (Elaeis guineensis) biomass without using any adhesives. Different parts of oil palm, including the core and mid sections of trunks, fronds, bark, and leaves, were used to make the panels with an average target density of 0.80g/cm3. Based on the test results, it seems that panels made from bark and leaves did not have satisfactory strength and dimensional stability. However, the panels having particles from the core portion of the trunks exhibited the highest modulus of rupture and internal bond strength but lowest in thickness swelling and water absorption values among the samples. The panels made with particles of mid-section of trunks and fronds followed the samples having core portion trunks material. Three types of raw material, namely fronds, mid-, and core-parts of the trunks appeared as though they could have potential to manufacture particleboard panels with acceptable properties based on requirements stated in Japanese Industrial Standard (JIS). Similar to the above findings, surface quality of the samples were also found acceptable for the panels made from three types of particles. Based on the results of this work, oil palm in the form of biomass could be considered as an environmentally friendly alternative raw material to manufacture binderless particleboard panels.

The separation of ethylene from ethane is particularly complex due to their similar physical properties. Cryogenic distillation is the most common technology employed for this separation and is one of the most expensive operations in industry, being the driving force for the ongoing research to find a more cost-effective alternative. In the present work, a gas-phase simulated moving bed (SMB) bench unit was employed to produce polymer-grade ethylene from ethane/ethylene mixtures, using binderless 13X zeolite beads as adsorbent, and propane as desorbent. The achieved performance parameters demonstrated the high efficiency of the current technology, since ethylene was obtained with a purity of 99.8%, a recovery of 99.8%, and a productivity of 59.7 kgC2H4·h−1· [ABSTRACT FROM AUTHOR]

The phases, microstructures and mechanical properties of binderless WC bulk materials prepared by the spark plasma sintering technique were investigated systematically. The addition of carbon was added to eliminate the impurity phase W2C. The relative density, Vickers hardness and grain size increase obviously with increasing sintering temperature, but increase weakly with increasing pressure or sintering time. The high relative density of 99·1%, HV30 of 27·5 GPa and fracture toughness KIC of 4·5 MPa m1/2 of pure binderless WC bulk with a grain size of 400 nm was obtained by sintering the WC powders with a particle size of 200 nm and the addition of 0?63 wt-%C at 1800°C for 6 min under 70 MPa. [ABSTRACT FROM AUTHOR]

Membrane electrode assemblies (MEAs) with ultra-low Pt loading electrodes were prepared for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) based on acid doped polybenzimidazole. With no electrode binders or ionomers, the triple phase boundary of the catalyst layer was established by the acid transfer from the acid doped membrane to the electrodes and can therefore be tailored by using catalysts with varied Pt to C ratios. With a loading of ca. 0.1 mg Pt cm −2 on each electrode the best performance was obtained with electrodes prepared from 10 wt.% Pt/C due to the improved Pt dispersion, extended triple phase boundary upon the acid transfer and the alleviated acid flooding of the catalytic layer. The MEA delivered a peak power density of 482 mW cm −2 for H 2 /O 2 and 321 mW cm −2 for H 2 /air, corresponding to an overall Pt utilization of 2.5 and 1.7 kW g Pt −1 , respectively. The durability test revealed no net voltage decay during more than 1700 h of uninterrupted operation at 200 mA cm −2 and 160 °C. [ABSTRACT FROM AUTHOR]

Tantalum carbide (TaC) ceramics without sintering additives or transition metals were consolidated within a sintering temperature range of 1350–1900 °C using a resistance-heated hot-pressing technique. Dense TaC ceramics having relative density values above 98 vol.% were obtained at temperatures exceeding 1375 °C, and only the TaC phase with stoichiometric or closely stoichiometric compositions was detected in the sintered bodies. The average grain size of the TaC grains increased significantly with sintering temperature. Young's modulus for dense, pure TaC ceramics (relative density > 98 vol.%) ranged from 531 to 549 GPa; a fully dense TaC ceramic was estimated to have a Young's modulus value of 558 GPa. The hardness of the dense TaC ceramic was ~ 14 GPa, regardless of the TaC average grain size, and the fracture toughness was ~ 4 MPa m 0.5 . The electrical resistivity of the TaC ceramic was 0.36 μΩ m at 20 °C and increased linearly with temperature. The thermal conductivity of the TaC ceramic, 27.9 W (m K) − 1 at 25 °C, increased with temperature. [ABSTRACT FROM AUTHOR]

Current energy shortage and environmental issues resulting from the use of fossil fuels have led to exploitation of renewable energy resources that includes municipal waste and agricultural residues. These residues are available, indigenous and are environmental friendly but some cannot be used directly in combustion process due high moisture content and low volumetric energy unless by briquetting. The study was undertaken to assess the combustion characteristic of binder-less briquettes produced from waste paper and groundnut shell. Combustion characteristics investigated were ignition time, burning time, calorific values, burning rate, specific fuel consumption, fuel efficiency and water boiling time. The calorific values of the briquettes ranged from 19.51 - 19.92 MJ/kg, while the thermal efficiency ranges between 13.75 - 21.64%, other results shows that the average burning rate between 0.511 and 1.133 kg/hr and the specific fuel consumption ranges between 0.087 and 0.131 J/g. The recorded boiling time values were between 17.5 and 30.0 minutes for cold start and 15.0 and 20.0 minutes for hot start. The results shows that waste paper and groundnut shell up to 25% in composition composite briquettes were found to have good combustion characteristics which qualify them as alternative to firewood for domestic and industrial energy. However, production of briquettes from waste paper and groundnut shell at mixing ratio of 85:15 was found to comparatively better from all experiment conducted. [ABSTRACT FROM AUTHOR]

A fast and facile approach based on potentiostatic electrochemical polymerization was used to prepare a polypyrrole/graphene oxide/zinc oxide (PPy/GO/ZnO) nanocomposite deposited on a flexible nickel foam. Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy revealed the presence of zinc oxide on the PPy/GO/ZnO nanocomposite. A supercapacitor was fabricated by sandwiching a filter paper immersed in a sodium sulfate solution between two nickel foam electrodes coated with the PPy/GO/ZnO nanocomposite. The electrochemical performance of the supercapacitor was characterized using a two-electrode configuration, and the cyclic voltammetry curve recorded at a fast scan rate of 100 mV/s was pseudo-rectangular. A specific capacitance of 94.6 F/g at a current density of 1 A/g was obtained from constant current charge/discharge measurements. The utilization of the pseudo-capacitive behavior of the polypyrrole and zinc oxide, and the electrical double layer capacitance of the graphene oxide, gave rise to a high energy and power density of 10.65 Wh/kg and 258.26 W/kg at 1 A/g, respectively. The capacitance of the supercapacitor after 1000 galvanostatic charge/discharge cycles was 74% of its original value. The potential application of the as-fabricated supercapacitor in realistic energy delivery systems was demonstrated by its ability to light up a light emitting diode for about 2 minutes after being charged for approximately 30 seconds. [ABSTRACT FROM AUTHOR]

Rape straw as a waste product of the oilseed industry is available abundantly in the European Union. In this paper, the utilization of rape straw-based fibers for the preparation of binderless thermal insulation materials is investigated. The effect of steaming temperature, which can be considered as one of the most important parameters of the production process, on microstructure and mechanical, hygric and thermal properties of the insulation boards is analyzed. The experimental results show that the designed binderless rape straw fiberboards achieve the most suitable combinations of mechanical, hygric and thermal properties for the steaming temperatures of 180 °C and higher, which indicates 180 °C as the most promising solution. • Binderless rape straw fiberboards with a bulk density of 100 kg/m3 were designed. • The effect of steaming temperature is analyzed. • Thickness swelling decreased substantially with increasing steaming temperature. • The most suitable properties achieved fiberboards produced at 180 °C and 200 °C. • The thermal conductivity was within the range of 0.045–0.052 W/mK. [ABSTRACT FROM AUTHOR]

As the worldwide demand for fuels and materials increases, fossil resources are decreasing and global warming is a concern, and thus the need for alternative solutions is high. In the industries of furniture and housing, particleboards are interesting materials, as they reutilize wastes from other industries (wood, agriculture) although they also rely on chemical binders that are petroleum-based and toxic. A very promising alternative is then clearly identified in finding ways to produce binderless boards and associated materials. This review considers the state of the art in the field of binderless board production, and other processes making it possible to turn raw plant fibers into structural materials without using any external chemistry. The mechanical properties and water resistance are collected and compared. Identified chemistry changes occurring during the thermo-compressive process are discussed with an aim towards understanding of the mechanisms of cohesion. [ABSTRACT FROM AUTHOR]

The present paper reports work in development of biocomposite boards compression moulded from wheat straw. Unlike most traditional wood based fibre/chip boards with addition of adhesives or bonding agents, attempt was made to utilise the lignin'hemicellulosic natural resin within straw as bonding agent, resulting in a class of 'binderless' and more natural biocomposite boards. The effects of straw preparation and compression moulding conditions on structural and mechanical properties of the binderless straw boards were studied systematically in terms of size of chopped straw, pretreatment and the combination of pressure and temperature during compression moulding. The bonding mechanisms of the natural resin in the straw biocomposites were investigated in terms of its mobilisation using NaOH pretreatment of straw and its redistribution to the straw interfaces during compression moulding process. Without any fractionation of straw or any additional adhesive bonding agent, the mechanical properties of the binderless straw boards were comparable to some commercially available wood and straw board products using addition of adhesives. [ABSTRACT FROM AUTHOR]

Abstract: Cr3C2, NbC, or ZrC was added to WC–4.85mol% SiC–1mol% Mo2C ceramics and sintered at 1600°C using a resistance-heated hot-pressing machine. Dense ceramics containing 0–0.3mol% Cr3C2, 0–3mol% NbC, and 0–10mol% ZrC were obtained. An additive carbide-based solid solution was observed only for NbC and ZrC additions. The coarse plate-like WC grains disappeared with the addition of Cr3C2, NbC, or ZrC and the ceramics consisted of fine equiaxed WC grains. Higher hardnesses, 19.4–21.8GPa, were measured for the carbide-added WC–SiC–Mo2C ceramics than for the WC–4.85mol% SiC ceramics because of the disappearance of coarse plate-like grains. The addition of a small amount of ZrC improved the fracture toughness without reducing the hardness. [Copyright &y& Elsevier]

Pressing beech veneers at high temperatures has been shown to be a reliable method for manufacturing laminated boards without adhesives. The reasons behind the self-bonding phenomenon as well as the causes of the waterproof character gained by the boards being pressed at 250 °C were investigated. Water leachates from the dried and the hot-pressed veneers were analysed by UV-spectroscopy, high-performance liquid chromatography (HPLC), and solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C NMR). Press-plate temperatures during hot pressing were 200, 225, and 250 °C. After pressing, an increased content of 5-(hydroxymethyl)furfural (not at 250 °C) and conjugated phenols was observed in the bonding lines (interfaces) compared to the inner part of veneers of the self-bonded boards. Furfural contents were low and relatively similar, but 5-(hydroxymethyl)furfural (HMF) showed an abrupt decrease in the bonding line when the temperature increased from 200 °C to 225 °C and especially to 250 °C. The contribution of caramelization to browning and bonding is suggested. In studies with CP/MAS 13C NMR, a higher content of phenolic units in beech lignin was observed during hot pressing at 225 °C. Homolytical cleavage of β-O-4 structures in lignin as well as the condensation reactions involved are discussed. [ABSTRACT FROM AUTHOR]

Utilization of oil palm trunk waste for production of environmental friendly binderless particleboard was studied. Response surface methodology was used to optimize the manufacturing conditions. The steaming temperature (100 to 120°C), steaming time (25 to 50 min), hot pressing temperature (180 to 220°C), and hot pressing time (15 to 30 min) were optimized in the ranges shown. The optimum conditions for making the particleboard were found to involve steaming for 46 min at a temperature of 120°C before it was compressed using a pressure of 12 MPa, at a temperature 215 °C for 29 min. The internal bond (IB) strength, modulus of rupture (MOR), thickness swelling (TS), and water absorption (WA) were 0.54 MPa, 8.18 MPa, 22%, and 51%, respectively. The residual values of actual and model-based calculated IB, MOR, TS, and WA were found to be 0.1 MPa, 0.23 MPa, 2%, and 4%, respectively, which shows the significance of the study. [ABSTRACT FROM AUTHOR]

This paper describes the features of binderless particleboard manufactured from sugarcane bagasse, under a high pressing temperature of 200-280 °C. Mechanical properties [i.e., modulus of rupture (MOR) and elasticity (MOE) in dry and wet conditions, internal bonding strength (IB)] and dimensional stability [i.e., thickness swelling (TS)] of the board were evaluated to investigate the effect of high pressing temperature. Recycled chip binderless particleboards were manufactured under the same conditions for comparison, and particleboards bonded with polymeric methylene diphenyl diisocyanate (PMDI) resin were manufactured as reference material. The target density was 0.8 g/cm for all of the boards. The results showed that the mechanical properties and dimensional stability of both types of binderless boards were improved by increasing the pressing temperature. Bagasse showed better performance than that of recycled chip as a raw material in all evaluations. Bagasse binderless particleboard manufactured at 260 °C had an MOE value of 3.5 GPa, which was equivalent to the PMDI particleboard, and a lower TS value of 3.7 % than that of PMDI particleboard. The MOR retention ratio under the dry and wet conditions was 87.0 %, while the ratio for the PMDI particleboard was only 54.6 %. The obtained results showed the possibility of manufacturing high-durability binderless particleboard, with good dimensional stability and water resistance, which previously were points of weakness for binderless boards. Manufacturing binderless boards under high temperature was effective even when using particles with poor contact area, and it was possible to express acceptable properties to allow the manufacture of particleboards. Further chemical analysis indicated a contribution of a saccharide in the bagasse to the improvement of the board properties. [ABSTRACT FROM AUTHOR]

Abstract: Of all the challenges facing human beings in the near future, energy related issues are likely to be the grandest. To achieve a more sustainable society with adequate renewable energy and less environmental pollution, more versatile, robust and efficient approaches in electric energy storage and conversion are needed. To achieve these goals, the development of new electrode materials with high electrical conductivity, corrosion-resistance, high specific surface area, high porosity and low cost is highly desirable. Graphene aerogels (GAs) have been focused recently due to novel properties of graphene (extremely low electrical and thermal resistivity, large carrier mobility, high surface area and mechanical elasticity) and the low cost and easy preparation of graphene from graphite. The performance of GA-based electrodes strongly depends on the morphology and structure of the GAs. However, there has been little study on the optimization of the GA nanostructures in terms of surface area, pore size, pore volume and density for energy storage devices. In this work, the GA nanostructures synthesized from commercial graphite were controlled successfully. The graphene oxide (GO) was prepared from commercial graphite powder using a modified Hummers method. A hydrothermal method was used to synthesize GAs due to its simplicity, environmental friendliness and low cost. No binders were used to prevent their negative effects to the electrical conductivity of the aerogels. Effects of fabrication conditions and the GO concentration on the GA nanostructures were also quantified. A maximum Brunauer–Emmett–Teller (BET) surface area of 394m2/g and the lightest density of 0.042g/cm3 were achieved when the GA with 3mgGO/mL was hydrothermally treated at 180°C for 1.5h. The thermal durability analysis showed that the GAs could be stable up to 500°C in air, with 24h of hydrothermal treatment time. Preliminarily the GA hydrothermally treated for 6h had an electrical conductivity of 0.004S/cm. The experimental results of the study are useful for optimizing GA structures for energy storage applications. [Copyright &y& Elsevier]

The objective of the study was to investigate physical and mechanical properties of experimental particleboard panels manufactured from oil palm (Elaeis guineensis) biomass without using any adhesives. Different parts of oil palm, including the core and mid sections of trunks, fronds, bark, and leaves, were used to make the panels with an average target density of 0.80g/cm³. Based on the test results, it seems that panels made from bark and leaves did not have satisfactory strength and dimensional stability. However, the panels having particles from the core portion of the trunks exhibited the highest modulus of rupture and internal bond strength but lowest in thickness swelling and water absorption values among the samples. The panels made with particles of mid-section of trunks and fronds followed the samples having core portion trunks material. Three types of raw material, namely fronds, mid-, and core-parts of the trunks appeared as though they could have potential to manufacture particleboard panels with acceptable properties based on requirements stated in Japanese Industrial Standard (JIS). Similar to the above findings, surface quality of the samples were also found acceptable for the panels made from three types of particles. Based on the results of this work, oil palm in the form of biomass could be considered as an environmentally friendly alternative raw material to manufacture binderless particleboard panels. [ABSTRACT FROM AUTHOR]