Thermal Treatment Procedure Research Articles

Considerations for the safe handling and processing of unstable materials

AbstractWe evaluate the instability hazards of initiators, monomers, and other unstable materials during storage and handling in individual containers, pallets of containers, and storage and process vessels. We propose a simplistic model to analyze the temperature–time profile of an unstable chemical, given heat transfer from/to the environment, heat generation due to decomposition and other reaction kinetics, and heat generated from auxiliary equipment (e.g., agitators/mixers, pumps, vessel jackets). Lumped capacitance‐based heat transfer and decomposition kinetics are integrated to predict self‐accelerating decomposition temperature (SADT), self‐accelerating polymerization temperature (SAPT), and the temperature profile given exposure conditions (e.g., ambient temperature and additional sources of heat). Case studies related to the storage and processing of unstable liquid monomers (i.e., methyl methacrylate, MMA), and organic peroxides, (i.e., tert‐butyl peroxybenzoate, TBPB), are presented. We also provide recommendations on determining safe storage and processing temperatures and steps to prevent emergency situations and include an overview of thermal analysis and data treatment procedures which might affect chemical process safety recommendations.

The Role of Surface Oxygen in Eliminating Fluorine Impurities and Relithiation Towards Direct Cathode Recycling

Recycling materials back to supply chain not only mitigates the shortage of critical materials such as the metals of Li, Ni, Co, etc, but also protects global environment. Direct recycling of lithium nickel manganese cobalt oxides (NMC) mainly relies on a relithiation process based on purified spent NMC cathode materials. How to efficiently get rid of chemically bonded surface impurities on spent NMC and obtain a clean surface is critical for relithiation. One of the unavoidable impurities is fluorine, which exists in the form of either carbon fluoride (CFx) or metal fluoride (M-F) and can be eliminated by either thermal treatment or hydrothermal procedure under alkaline environments depending on the state of the F.1,2 Generally the hydrothermal method needs relative high temperature (> 200 °C ) and long reaction time (> 16 hours) due to the slow kinetics. A redox mediator such as H2O2, ethanol or ethylene glycol has been reported to be effective to lower the temperature and pressure for relithiation of recycled NMC111 and NMC622, which was pretreated with N-Methyl-2-pyrrolidone solvent.3 However the mechanism is still not fully understood.This work combines material characterizations and electrochemistry and density functional theory (DFT) calculations to study the role of surface oxygen in eliminating fluorine species on recycled NMC532 cathode material. The recycled NMC532 powders were separated from graphite by froth flotation method and there were significant amount of fluorine impurity species on the surface confirmed by XPS. Initial trial of the addition of small amount of H2O2 additive to LiOH aqueous solution during the hydrothermal process was able to decrease the reaction time significantly to fully eliminate both CFx and M-F species compared to the reaction without H2O2. Further calcination steps with the addition of 5% excessive lithium source using LiOH successfully recovered the recycled NMC532 and the half coin cell using the rejuvenated cathode materials shows a discharge capacity of 154 mAh/g at 0.2 C within 2.7 to 4.2 V voltage range. DFT calculations was conducted on a NMC (012) surface and both lithium hydroxide and sodium hydroxide were selected to understand the role of OH- group and surface oxygen species. The kinetics study was conducted with transition state theory4 and the activation energy barriers were calculated by climbing image nudged elastic band (cNEB) method.5,6 The removal of surface F- takes place with the displacement of F- with OH- (*-(M)F(s) +XOH(s) à XF(s) + *-(M)OH(s), X= Li, Na). F- displacement reactions require more than one basic molecule per F- removal with the formation of either LiF or NaF, which is soluble in water and can be removed by a filtration process. Depending on the surface ‘foreign’ oxygen species, the reaction can either go with a hydroxide pathway or a peroxide pathway, with the latter involving the formation of a peroxide intermediate with a ‘foreign’ oxygen atom leading to much smaller barrier energy compared to that in the hydroxide pathway. On a delithiated surface, the barrier energy for F- removal is predicted to be higher than pristine surfaces as the delithiated surface is less reactive to bind ‘foreign’ oxygen. This is consistent with the experimental results in which the additive of H2O2 can provide ‘foreign’ oxygen atoms and favors peroxide pathway leading to shorter time to remove surface fluorine. Additionally, the reaction with NaOH has a lower barrier than that with LiOH for the removal of fluoride species. Future work will investigate alternative additives as well as fluorine surface-bulk transfer which potentially happen if small amount of fluorine residues exist during calcination step.

Eigenvalue approach for investigating thermal and mechanical responses on living tissues during laser irradiation with experimental verification

This study provides analytical solutions for the non-Fourier theory, which accounts for bioheat transfer in biological tissue when exposed to laser irradiation. To perform thermal treatment procedures effectively, a thorough comprehension of both the heat transmission mechanism and the subsequent thermal and mechanical interaction within the patient's human tissue is essential. The assessment of thermal injuries to the tissue involves determining the extent of denatured proteins using the Arrhenius formulation. The bio-thermoelastic model presented employs Laplace transforms and analytical techniques to establish governing formulations. Subsequently, an eigenvalues scheme is utilized to derive solutions to these equations. Graphical representations of the results for temperature, displacements, and stress are provided. The analytical solution's accuracy is verified through a comparison with numerical and experimental data. Results indicate that, when both have zero thermal lag times, the generalized non-Fourier model aligns with the Pennes bioheat transfer model. Furthermore, the effectiveness of the mathematical model in evaluating bioheat transfer in biological tissues is validated by comparing it with established experimental data.

The impact of fractional derivative on thermomechanical interactions in two-dimensional skin tissues throughout hyperthermia treatment

This work aims to study the influence of fractional derivatives and thermal relaxation time on two-dimensional biological tissues using an eigenvalue-based approach. Understanding the heat transfer mechanism and its thermomechanical interactions with the skin tissue of patients is crucial for the successful implementation of thermal treatment procedure. The study employs Laplace and Fourier transforms, and the resulting formulations are applied to human tissues undergoing regional hyperthermia treatment for tumor therapy. The numerical inversion process for Laplace and Fourier transformations utilizes the Stehfest numerical inverse method. The results demonstrate that thermal relaxation time and fractional order parameter significantly influence all analyzed distributions. The numerical findings suggest that thermo-mechanical waves propagate through the skin tissue over finite distances, which helps mitigate the unrealistic predictions made by the Pennes' model.

Block copolymer-templated gasochromic WO3 thin films with uniform mesopores for fast optical hydrogen sensing

A method to prepare mesoporous WO3 thin films (represented by MP-WO3) with a uniform pore size of ∼18 nm is developed successfully by utilizing poly(ethylene oxide)-b-polystyrene (PEO-b-PS) as the structure-directing agent (SDA). The properties of the gasochromic MP-WO3 thin film are studied in detail and compared with the control groups prepared by using homopolymer PEO, PS, or their mixtures as SDA. Utilizing an optimized thermal treatment procedure, the gasochromic MP-WO3 thin film of which the transmittance change ΔT is 59.1% exhibites the fastest coloration and bleaching speed with a coloration time of 27.3 s and a bleaching time of 19.7s as well as excellent reversibility within 90 cycles. This study offers a new strategy and insight into the development of mesoporous WO3 hydrogen gasochromic films with excellent performances and paves its way toward the application of an optical hydrogen sensor.

Computer simulation of two phase power-law nanofluid of blood flow through a curved overlapping stenosed artery with induced magnetic field: entropy generation optimization

PurposeThe purpose of this study is to determine the impact of two-phase power law nanofluid on a curved arterial blood flow under the presence of ovelapped stenosis. Over the past couple of decades, the percentage of deaths associated with blood vessel diseases has risen sharply to nearly one third of all fatalities. For vascular disease to be stopped in its tracks, it is essential to understand the vascular geometry and blood flow within the artery. In recent scenarios, because of higher thermal properties and the ability to move across stenosis and tumor cells, nanoparticles are becoming a more common and effective approach in treating cardiovascular diseases and cancer cells.Design/methodology/approachThe present mathematical study investigates the blood flow behavior in the overlapped stenosed curved artery with cylinder shape catheter. The induced magnetic field and entropy generation for blood flow in the presence of a heat source, magnetic field and nanoparticle (Fe3O4) have been analyzed numerically. Blood is considered in artery as two-phases: core and plasma region. Power-law fluid has been considered for core region fluid, whereas Newtonian fluid is considered in the plasma region. Strongly implicit Stone’s method has been considered to solve the system of nonlinear partial differential equations (PDE’s) with 10–6 tolerance error.FindingsThe influence of various parameters has been discussed graphically. This study concludes that arterial curvature increases the probability of atherosclerosis deposition, while using an external heating source flow temperature and entropy production. In addition, if the thermal treatment procedure is carried out inside a magnetic field, it will aid in controlling blood flow velocity.Originality/valueThe findings of this computational analysis hold great significance for clinical researchers and biologists, as they offer the ability to anticipate the occurrence of endothelial cell injury and plaque accumulation in curved arteries with specific wall shear stress patterns. Consequently, these insights may contribute to the potential alleviation of the severity of these illnesses. Furthermore, the application of nanoparticles and external heat sources in the discipline of blood circulation has potential in the medically healing of illness conditions such as stenosis, cancer cells and muscular discomfort through the usage of beneficial effects.

Bifunctional TiCo electrocatalysts based on N-doped graphene cryogels for the oxygen evolution and reduction reactions

Three-dimensional N-doped graphene cryogels (NGC) modified with Ti and Co nanoparticles are investigated as bifunctional oxygen electrocatalysts for potential application in unitized regenerative fuel cells (URFCs). These composites have been successfully produced via a combined solvothermal, freeze-drying, and thermal treatment procedure. Crystallographic structure, surface properties, and morphology are analyzed to study the influence of each metal and the bimetallic combination in forming active sites for oxygen reduction (ORR) and oxygen evolution (OER) reactions. The intrinsic catalytic activity of the composites was determined by rotating disk electrode and further assessed in a gas diffusion electrode to test them in more realistic conditions for URFCs in 6 M KOH. Results revealed the remarkable bifunctional activity of Co/NGC and bimetallic TiCo/NGC composites. The synergistic effect of the metallic cobalt and surface atomic composition of Co3O4 distributed on the N-doped graphene cryogel in Co/NGC is responsible for the high bifunctional performance. Moreover, the partial substitution of cobalt for a less critical raw material, such as titanium, allows the electrocatalyst to maintain great bifunctional activity and stability. The nitrogen doping of the graphene cryogel structure can influence the anatase/rutile titania ratio that forms during pyrolysis. As a result, defects, oxygen vacancies, and Ti3+ species are formed, which, when combined with Co nanoparticles, contribute to the outstanding performance and stability of the TiCo/NGC composite. The excellent performance of N-doped graphene cryogel-based electrocatalysts in GDE conditions indicates their potential use in electrochemical processes, which involve gas-phase reactions.

Effects of ultrasonic treatment on the structural, functional properties and beany flavor of soy protein isolate: Comparison with traditional thermal treatment

This research explored the influences of ultrasonic and thermal treatments on the structure, functional properties, and beany flavor of soy protein isolate (SPI). In comparison with traditional thermal treatment, ultrasonic treatment effectively induced protein structural unfolding and exposure of hydrophobic groups, which reduced relative content of α-helix, increased relative content of β-turn, β-sheet and random coil, and improved the solubility, emulsifying and foaming properties of SPI. Both treatments significantly decreased the species and contents of flavor compounds, such as hexanal, (E)-2-nonenal, (Z)-2-heptenal and (E)-2-hexenal in SPI. The relative content of hexanal in the major beany flavor compound decreased from 11.69% to 6.13% and 5.99% at 350 W ultrasonic power and 150 s thermal treatment procedure, respectively. After ultrasonic treatment, structural changes in SPI were significantly correlated with functional properties but showed a weak correlation with flavor. Conversely, the opposite trend was observed for thermal treatment. Thus, using ultrasonic treatment to induce and stabilise the denatured state of proteins is feasible to improve the functional properties and beany flavor of SPI.

Performance and reliability enhancement of flexible low-temperature polycrystalline silicon thin-film transistors via activation-annealing temperature optimization

The high performance and reliability of low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) on flexible substrates need to be ensured for the proper operation of advanced flexible organic light-emitting diode (OLED) displays. However, due to the heat-sensitive components of flexible LTPS TFTs, their fabrication process faces challenges in the temperature management of its thermal treatment procedures such as activation annealing, which is an essential step in the in-line fabrication process of LTPS TFTs for activating dopants and reducing silicon lattice-related structural defects. In this work, we investigate the optimization of the activation-annealing process through the modulation of its process temperature. As the activation-annealing temperature was increased from 320 °C to 370 °C, the electrical characteristics and reliability of flexible LTPS TFTs improved owing to a decrease in the gate dielectric/channel interface and bulk channel defects. However, as the temperature was further increased to 420 °C, considerable degradations in device performance and reliability were observed due to a significant increase in the deep-level gate dielectric/channel interface and bulk channel defects. Physical analysis revealed that significant dehydrogenation, in which the breakage of Si−H bonds causes excess Si dangling bonds, occurred at 420 °C. This work shows that a fine temperature optimization of the activation annealing process is a necessary procedure for ensuring highly performant and reliable LTPS TFTs on flexible substrates.

The Effect of Fractional Derivatives on Thermo-Mechanical Interaction in Biological Tissues during Hyperthermia Treatment Using Eigenvalues Approach

This article studies the effects of fractional time derivatives on thermo-mechanical interaction in living tissue during hyperthermia treatment by using the eigenvalues approach. A comprehensive understanding of the heat transfer mechanism and the related thermo-mechanical interactions with the patient’s living tissues is crucial for the effective implementation of thermal treatment procedures. The surface of living tissues is traction-free and is exposed to a pulse boundary heat flux that decays exponentially. The Laplace transforms and their associated techniques are applied to the generalized bio-thermo-elastic model, and analytical procedures are then implemented. The eigenvalue approach is utilized to obtain the solution of governing equations. Graphical representations are given for the temperature, the displacement, and the thermal stress results. Afterward, a parametric study was carried out to determine the best method for selecting crucial design parameters that can improve the precision of hyperthermia therapies.

Compositing ultrafine CoFe2O4 spinel with porous silica as catalyst for photothermal PMS activation and interfacial water evaporation

Although spinel oxides have been promising in advanced oxidation processes (AOP), multidimensional coupling via bimetallic redox cycles and photothermal synergy is still rare in AOP and environmental governance. Here, ultrafine plasmonic CoFe2O4 spinel nanoparticles (∼20 nm) were composited with porous silica and followed by a tuned thermal treatment procedure (600–900 °C) in N2 condition to obtain bimetallic nanocomposites. The resulting catalysts exhibited significant active interfacial effects and an increased proportion of Co (II) species in the spinel structure after the calcination process. The CoFe/SiO2-8 nanocatalysts effectively showed significant advantages in size structure and valence modulation compared to CoFe2O4 alone, and the prepared catalysts showed great potential for multiphase PMS activation with better photothermal effects. In addition, the introduction of SiO2 in the CoFe/SiO2-8 catalyst allows a higher activation efficiency of PMS during the catalytic degradation of bisphenol A. We also demonstrated that under photothermal (a simulated sunlight) conditions, 30 ppm BPA can be completely degraded within 30 min by coupling the photothermal effect with the catalyst, which is significantly better than the catalytic degradation behavior of only catalyst-participated BPA, achieving a promotive thermodynamic behavior and conversion efficiency. More importantly, solar-driven interfacial water evaporation by virtue of CoFe/SiO2-8 was explored to identify the practical potential possibility for the regeneration of freshwater from the polluted water resource.

Highly exfoliated graphitic carbon nitride for efficient removal of wastewater pollutants: Insights from DFT and statistical modelling

The present work entails the synthesis of thermally modified graphitic carbon nitride (GCN) using a two-step thermal treatment procedure and its subsequent use in the photocatalytic reduction of toxic pollutants such as rhodamine B dye (RhB) and chromium (VI) (Cr(VI)) from aquatic environments. The as-synthesised exfoliated GCN (GCNX) is characterised by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller analysis (BET), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). These characterisations helped to elucidate the phase formation, chemical structure, composition, surface area, optical properties, and morphology of the sample. With assistance from a visible light source, GCNX can degrade RhB dye within 30 min in the presence of hydrogen peroxide (H2O2) and reduce Cr(VI) to Cr(III) in under 2 h in the presence of formic acid (FA/HCOOH). Variations in different catalytic parameters, including catalyst amount, pH of the solution, initial RhB or Cr(VI) concentration, and variation in H2O2 or FA concentration, are performed to inspect their effects on the photodegradation activity of GCNX. Moreover, the GCNX catalyst exhibits impressive stability and reusability. A thorough statistical evaluation follows the response surface methodology to understand the complex interaction between the factors contributing to the catalytic activity. The band alignment of differently functionalised GCN blocks in their pristine form and their H2O2/FA-adsorbed states is investigated using first-principles calculations to provide a further understanding of the RhB and Cr(VI) reduction mechanisms. The modified GCN can thus be effectively employed as a low-cost material for removing contamination from aquatic environments.

Identifying Biological and Biophysical Features of Different Maturation States of α-Synuclein Amyloid Fibrils.

Protein aggregates, hereunder amyloid fibrils, can undergo a maturation process, whereby early formed aggregates undergo a structural and physicochemical transition leading to more mature species. In the case of amyloid-related diseases, such maturation confers distinctive biological properties of the aggregates, which may account for a range of diverse pathological subtypes. Here, we present a protocol for the preparation of α-synuclein amyloid fibrils differing in the level of their maturation. We utilize widely accessible biophysical techniques to characterize the structure and morphology and a simple thermal treatment procedure to test their thermodynamic stability. Their biological properties are probed by means of binding to native plasma membrane sheets originating from mammalian cell lines.

Structure‐Property Relations of Nickel and Cobalt Substituted Yttrium Aluminum Garnets as Catalyst Materials for Dry Reforming of Methane

AbstractNickel‐ and cobalt‐substituted yttrium aluminum garnets (YAGs) were synthesized varying their stoichiometries and the details of the thermal treatment procedures at elevated temperatures. Ni and/or Co substitution into the framework of Y3Al5O12 was found to be feasible up to molar metal contents of 6 mol %. The synthesis conditions were optimized towards a compromise of high phase purity of the high‐temperature phase of YAG, still maintaining sensible specific surface areas of the resulting catalyst materials. The two synthetic procedures evaluated in the study allow introduction of nickel and cobalt into the oxidic framework of the YAG oxide, from which under reducing conditions, both metals can be exsolved. The catalysts were studied in the catalytic dry reforming of methane under stoichiometric ratio of CO2/CH4 at atmospheric pressure. The catalytic results indicate that for the best candidate materials performance is stable and a syngas of the desired ratio nH2/nCO = 1 is formed. Trends were observed towards nickel being the catalytically more active metal compared to cobalt.

Finely tuning the microporosity in dual thermally crosslinked polyimide membranes for plasticization resistance gas separations

Thermally induced chemical crosslinking has attracted substantial attention for fabricating plasticization resistant membranes due to the facile structure tunability that enables the construction of robust and well-defined architecture for gas separation. In this study, we report a new series of dual thermally crosslinkable polyimides derived from 4,4′-diamino-2,2′-biphenyldicarboxylic acid (DCB) containing two carboxyl groups, and a systematic investigation of the thermal treatment above and below Tg demonstrated the decarboxylation-induced crosslinking. The dual thermally crosslinked membranes were insoluble in common organic solvents and maintained excellent mechanical properties. Due to the evolution of CO2 and collapse of chain segments during thermal treatment, the crosslinked membranes exhibited hierarchical microcavity size distribution featuring ultra-micropore size in the range of 2.0–6.0 Å and micropore size in the range of 6.5–10.0 Å. Gas transport properties of the crosslinked membranes were feasibly tuned through the chemical compositions and thermal treatment procedures. For instance, the CO2 permeability of crosslinked 6FDA-DAM0.7-TFMB0.1-DCB0.2 increased almost three-fold with only a slight decrease in CO2/CH4 selectivity. The crosslinked membranes also demonstrated superior plasticization resistance with mixed-gas feed pressure up to 40 bar and excellent low-temperature gas separation performance at −30 °C, making them attractive for aggressive gas separations.

Enabling Efficient Aerobic 5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid in Water by Interfacial Engineering Reinforced Cu-Mn Oxides Hollow Nanofiber.

Herein, a one-dimensional hollow nanofiber catalyst composed of tightly packed multiphase metal oxides of Mn2 O3 and Cu1.4 Mn1.6 O4 was constructed by electrospinning and tailored thermal treatment procedure. The characterization results comprehensively confirmed the special morphology and composition of various comparative catalysts. This strategy endowed the catalyst with abundant interfacial characteristics of components Mn2 O3 and Cu1.4 Mn1.6 O4 nanocrystal. Impressively, the tuning thermal treatment resulted in tailored CuI sites and surface oxygen species of the catalyst, thus affording optimized oxygen vacancies for reinforced oxygen adsorption, while the concomitant enhanced lattice oxygen activity in the constructed composite catalyst ensured the higher catalytic oxidation ability. More importantly, the regulated proportion of oxygen vacancy and lattice oxygen in the composite catalyst was obtained in the best catalyst, beneficial to accelerate the reaction cycle. Compared to other counterparts obtained by different temperatures, the CMO-500 sample exhibited superior selective aerobic 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA, 96 % yield) in alkali-bearing aqueous solution using O2 at 120 °C, which resulted from the above-mentioned composition optimization and interfacial engineering reinforced surface oxygen consumption and regeneration cycle. The reaction mechanism was further proposed to uncover the lattice oxygen and oxygen vacancy participating HMF conversion process.

A General Access Route to High‐Nuclearity, Metal‐Functionalized Molecular Vanadium Oxides

AbstractMolecular metal oxides are key materials in diverse fields like energy storage and conversion, molecular magnetism and as model systems for solid‐state metal oxides. To improve their performance and increase the variety of accessible motifs, new synthetic approaches are necessary. Herein, we report a universal, new precursor to access different metal‐functionalized polyoxovanadate (POV) clusters. The precursor is synthesized by a novel solid‐state thermal treatment procedure. Solution‐phase test reactions at room temperature and pressure show that reaction of the precursor with various metal nitrate salts gives access to a range of metal‐functionalized POVs. The first nitrate‐templated molecular calcium vanadate cluster is reported. We show that this precursor could open new access routes to POV components for molecular magnetism, energy technologies or catalysis.

A General Access Route to High-Nuclearity, Metal-Functionalized Molecular Vanadium Oxides.

Molecular metal oxides are key materials in diverse fields like energy storage and conversion, molecular magnetism and as model systems for solid‐state metal oxides. To improve their performance and increase the variety of accessible motifs, new synthetic approaches are necessary. Herein, we report a universal, new precursor to access different metal‐functionalized polyoxovanadate (POV) clusters. The precursor is synthesized by a novel solid‐state thermal treatment procedure. Solution‐phase test reactions at room temperature and pressure show that reaction of the precursor with various metal nitrate salts gives access to a range of metal‐functionalized POVs. The first nitrate‐templated molecular calcium vanadate cluster is reported. We show that this precursor could open new access routes to POV components for molecular magnetism, energy technologies or catalysis.

Rich Surface Oxygen Vacancies of MnO2 for Enhancing Electrocatalytic Oxygen Reduction and Oxygen Evolution Reactions

Development of catalysts for the electrochemical oxygen reactions, namely, oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), is critical for the application of various renewable energy technologies. The aim of this work is to prepare low‐cost MnO2 electrocatalyst with high activity for the ORR and OER via introduction of surface oxygen vacancies (OVs). Herein, the procedure of thermal heating treatment under air or H2 has been demonstrated as an efficient way to create OVs on the surface of α‐MnO2 and β‐MnO2 nanorods, which are found to be highly active for both ORR and OER. The existence of surface OVs can modulate the intrinsic activity of α‐MnO2 and β‐MnO2 and improve their ORR and OER kinetics. More importantly, the H2‐treated MnO2 possesses much more surface OVs and thus exhibits much better catalytic performances for ORR and OER in comparison with MnO2 obtained by common annealing treatments under air. Especially, the H2‐treated α‐MnO2 nanorods show the best activity for the ORR and OER. The results confirm that the heating treatment under H2 reducing atmosphere can be a facile and efficient process to develop bifunctional Mn‐based electrocatalysts for electrochemical oxygen reactions.

A facile crosslinking strategy endows the traditional additive flame retardant with enormous flame retardancy improvement

With great chemical and physical properties, epoxy resins (EPs) are used almost everywhere in life and engineering, but poor flame-retardant performance hinders them for a wider use. Traditional flame retardants (the most commonly used and researched) usually have dispersion and migration problems (additive ones) or are difficult to synthesize (reactive ones). Herein, a facile crosslinking strategy is used to make traditional additive flame retardants exhibit much better properties. Firstly, a nitrogen/phosphorus containing additive flame retardant with nitrile groups is designed, successfully synthesized, and directly mixed with EP matrix, the secondary crosslinking reaction of nitrile groups inner the flame retardants will occur in cured EP thermosets which was driven by a facile thermal treatment procedure. Then the properties of the flame retardant mixed and crosslinked EP composites are measured by limiting oxygen index (LOI) test, thermogravimetric analyses (TG), UL-94 vertical burning tests, dynamic mechanical analysis and cone calorimeter test, the results show that the crosslink of the additive flame retardant greatly improved the flame-retardant properties, and with 20 wt% loading content of the crosslinked flame retardant, the LOI value reach 46.2% and the peak heat release rate decreases for 77.4% compared with neat EP, furthermore the heat resistance and dynamic mechanical property of the crosslinked samples also get promoted compared with the physical mixed ones.