Excellent Thermostability Research Articles

A potential insensitive-highly-energetic material through conjugation-promoted N-oxidation strategy

Striking a well balance between energy, sensitivity and thermostability of high performing organic materials has become a big challenge in the community of energetic materials. In the recent years, simple N-oxidation approach based on nitropyrimidine and nitropyridazine has been disclosed since the year of 1995 when nitropyrazine-N-oxides (such as LLM-105:2,6-diamino-3,5-dinitropyrazine-1-oxide) was developed, however, the development of facile N-oxidation via fused heterocylic ring is still stagnant, which has strongly limited the appearance of advanced materials. Herein, we present the specific synthesis of novel energetic materials with excellent properties in different aspects based on pyrazolium[5,1-C][1,2,4]triazine framework. Especially, for the first time we synthesized pyrazolium[5,1-C][1,2,4]triazine N-oxide, which also suggests that N-oxidation has introduced more intramolecular hydrogen bonds and resulted in larger conjugation effect at the molecular level, giving rise to an effective strategy in improving energy, safety and thermostability of energetic materials simultaneously. All compounds exhibit high densities (1.872–1.917 g·cm−3) and energetic performance (8657–8990 m·s−1). Among them, 8-nitro-3-(1H-tetrazol-5-yl)pyrazolo[5,1-c]00triazine-4,7-diamine (FPT-3) and 4-amino-7,8-dinitro-3-(1H-tetrazol-5-yl)pyrazolo[5,1-c][1,2,4]triazine-2-oxide (FPT-4) hold brilliant onset decomposition temperatures (FPT-3: Td = 335 °C; FPT-4: Td = 273 °C), good detonation properties (FPT-3: Vd = 8657 m s−1; FPT-4: Vd = 8851 m·s−1) and very low sensitivities (FPT-3: IS > 60 J, FS > 360 N; FPT-4: IS > 55 J, FS > 360 N), which indicate that both compounds are high energy explosives with very low sensitivity and excellent thermostability.

Ligand-regulated polymerization of conjugated dienes catalyzed by confined iminopyridine iron complexes with high activity and thermal stability

A range of confined iminopyridine iron complexes with skeleton of 8-(arylimino)-5,6,7-trihydroquinolyl have been prepared and well characterized by HRMS spectroscopy, FT-IR spectroscopy as well as elemental analysis. These iron complexes (Fe1–Fe5) serve as highly efficient pre-catalysts for conjugated dienes polymerization. By adjusting substituents of ligand framework, the stereoselectivity about 1,4-cis/trans could be switched from <1/99 to 96/4. An outstanding polymerization activity up to 108 g mol−1 h−1 was achieved with high molecular weight by employing Fe1 as pre-catalyst under optimum experimental conditions. What's more, the Fe1/MAO catalytic system showed excellent thermostability, which could lead to full conversion even at 100 °C within 10 min. Surprisingly, the polymerization activities of bio-based monomer β-farnesene and β-myrcene were able to reach 106 g mol−1 h−1 by Fe-1/MAO catalytic system, which was the highest activity of iron complex family to deliver the “green rubbers” with high molecular weights.

Thermostable physically crosslinked cryogel from carboxymethylated konjac glucomannan fabricated by freeze-thawing

Physically crosslinked cryogels of carboxymethylated konjac glucomannan (CMKGM) with different molecular weights (Mw, 1.57 × 105–7.33 × 105 Da) and degrees of substitution (DS, 0.19–1.63) were fabricated by using the freeze-thaw technique. The acidification of CMKGM solution at a sufficiently low pH of 1.0 is a prerequisite to produce a cryogel. Both the Mw and DS of CMKGM significantly affected the formation and mechanical strength of the cryogels. A high DS value cannot ensure the formation of the cryogel when the Mw of CMKGM is not sufficiently high. While the cryogel from CMKGM with the highest Mw of 7.33 × 105 Da and lowest DS of 0.19 exhibited the highest gel strength, cryogels could not be effectively formed for CMKGM with a DS beyond 1 and Mw below 2.24 × 105 Da. Furthermore, the gel strength could be enhanced by increasing polysaccharide concentration, freezing time, and the number of freeze-thaw cycles or thawing at a moderate temperature (25 °C). It was demonstrated that the intermolecular multiple hydrogen bonding was the major driving force in the formation of CMKGM cryogels with negligible, if any, participation of crystalline ordered structures. Detailed hydrogen bonding patterns in the gel network were proposed. In acidic cryogels, there existed three types of hydrogen bonds formed by –COOH and –OH groups, whereas in neutral cryogels, two kinds of hydrogen bonding among -COO- and –OH groups were involved. The intermolecular multiple hydrogen bonding endows the physical hydrogels with excellent thermostability.

Covalent Organic Framework Membranes for Efficient Chemicals Separation

Covalent organic frameworks (COFs) are an emerging class of organic porous crystalline materials that are composed entirely by organic linkers and connected by strong covalent bonds. The unique characteristics including well‐ordered and tailorable pore channels, high and permanent porosity, excellent thermostability and chemical stability, and ease of functionalization enable COFs to perfectly meet the requirements for the fabrication of advanced separation membranes. Significant progress has been made in the preparation and application of COF membranes over the past few years. Herein, the structure—performance relationship of COF materials on membrane separation is first proposed. The effects of the intrinsic properties of COF materials on membrane separation performance are systematically summarized. The fabrication methods of COF membranes, including both bottom‐up strategy (in situ growth and interface‐assisted synthesis) and top‐down strategy (blending and layer‐by‐layer [LBL] stacking), are then discussed in detail. The application of COF membranes in gas separation (H2 purification, CO2 capture, hydrocarbon separation) and liquid phase separation (water treatment, organic solvent nanofiltration, pervaporation) is highlighted. Finally, the remaining challenges and issues to be resolved in the COF membranes are prospected from the perspective of COF materials.

High through-plane thermal conductivity and light-weight of UHMWPE fibers/PDMS composites by a large-scale preparation method

The high through-plane thermal conductivity of thermal interface materials (TIMs) is a major challenge in the thermal management of electronic devices. In this work, we have developed a large-scale fabrication process for high through-plane thermal conductivity of ultrahigh molecular weight polyethylene (UHMWPE) fibers/PDMS unidirectional (UD) composites using aligned UHMWPE fibers as filler and PDMS as the matrix. Due to the high orientation (0.93) and high crystallinity (90%), the UHMWPE fibers provided an effective thermal conductive pathway along with the fiber's axis. The results showed the thermal conductivity of UHMWPE fibers/PDMS UD composites was up to 4.03 W/m·K, which is increasing by ca. 2140% compared with that of pure PDMS (0.22 W/m·K). Moreover, the composites have versatile properties such as low density (ca. 1.0 g/cm3), good compressibility, and excellent thermostability. It has great potential in industry-scale applications for TIMs.

A flexible, heat-resistant and self-healable “rocking-chair” zinc ion microbattery based on MXene-TiS2 (de)intercalation anode

The requirement for rechargeable microbatteries (MBs) continues to increase due to the rapidly development of wearable and integrated electronics. However, the ever-reported mainstream MBs, such as lithium ion MBs, have intrinsic drawbacks of security threats and environmental hazards, and are not suitable as an energy supply component for wearable electronics. Here, a safe and environmentally friendly zinc ion microbattery (ZIMB) based on MXene-TiS2 (de)intercalation anode, multi-walled carbon nanotubes-vanadium dioxide (B) (MWCNTs-VO2 (B)) cathode, zinc sulfate-polyacrylamide (ZnSO4-PAM) hydrogel electrolyte and self-healable polyurethane (PU) protective shell is exploited. The ZIMB exhibit satisfactory electrochemical performance with a capacity of 40.8 μAh cm-2, maximum power density of 32.5 μWh cm-2 and maximum energy density of 1.2 mW cm-2. In addition, the ZIMB also exhibits the excellent flexibility, thermostability and self-healability, i.e., no significant attenuation in capacity can be observed when the ZIMB is placed on the specific conditions, such as the high bending angle of 150°, high temperature of 100 °C, and multiple damage and repair cycles. This study provides a feasible strategy to develop advanced high reliable and stable micro energy storage devices for wearable and integrated electronics.

Thermal and Mechanical Performances of the Superflexible, Hydrophobic, Silica-Based Aerogel for Thermal Insulation at Ultralow Temperature.

A superflexible hydrophobic silica-based aerogel (FHSA) was prepared via a facile sol-gel process and ambient pressure drying method. The FHSA was treated at different temperatures varying from -196 to 450 °C to evaluate its thermal and mechanical performances. The evolutions of the physical property, hydrophobicity, microstructure, pore structure, and chemical structure of the FHSA with the various treatment temperatures were investigated comprehensively. The structure of the FHSA did not show an obvious change after treatment in the liquid nitrogen. The bulk density of the FHSA increased from 0.047 to 0.077 g cm-3 when the thermal treatment temperature increased from 25 to 450 °C. The specific surface area and pore volume of the FHSA increased with the treatment temperature owing to the decomposition of the organic moieties. The Fourier transform infrared spectra showed that the methyl groups in the FHSA had excellent thermostability up to 400 °C. The water contact angles of the FHSA after treatment at -196, 25, 200, 300, 350, 400, and 450 °C were 131, 151, 162, 150, 132, 119, and 34°, respectively. The thermal conductivity of the FHSA at a low temperature of -10 °C was 0.022 W m-1 K-1. The reversible deformation rate of the FHSA was more than 80% within 100 compression cycles. After treatment in liquid nitrogen, the reversible deformation rate of the FHSA remained at 50%. The synthesis method of the FHSA is simple, the resulting FHSA showed good performance both in thermostability and flexibility, and it is promisingly applied for thermal insulation and sealing in ultralow-temperature environments.

Extra disulfide and ionic salt bridge improves the thermostability of lignin peroxidase H8 under acidic condition

The development of a lignin peroxidase (LiP) that is thermostable even under acidic pH conditions is a main issue for efficient enzymatic lignin degradation due to reduced repolymerization of free phenolic products at acidic pH (< 3). Native LiP under mild conditions (half-life (t1/2) of 8.2 days at pH 6) exhibits a marked decline in thermostability under acidic conditions (t1/2 of only 14 min at pH 2.5). Thus, improving the thermostability of LiP in acidic environments is required for effective lignin depolymerization in practical applications. Here, we show the improved thermostability of a synthetic LiPH8 variant (S49C/A67C/H239E, PDB: 6ISS) capable of strengthening the helix–loop interactions under acidic conditions. This variant retained excellent thermostability at pH 2.5 with a 10-fold increase in t1/2 (2.52 h at 25 °C) compared with that of the native enzyme. X-ray crystallography analysis showed that the recombinant LiPH8 variant is the only unique lignin peroxidase containing five disulfide bridges, and the helix–loop interactions of the synthetic disulfide bridge and ionic salt bridge in its structure are responsible for stabilizing the Ca2+-binding region and heme environment, resulting in an increase in overall structural resistance against acidic conditions. Our work will allow the design of biocatalysts for ligninolytic enzyme engineering and for efficient biocatalytic degradation of plant biomass in lignocellulose biorefineries.

Identification and Characterization of an O-Succinyl-L-Homoserine Sulfhydrylase From Thioalkalivibrio sulfidiphilus.

L-methionine is an important natural amino acid with broad application prospects. A novel gene encoding the enzyme with the ability to catalyze O-succinyl-L-homoserine (OSH) to L-methionine was screened and characterized. The recombinant O-succinyl-L-homoserine sulfhydrylase from Thioalkalivibrio sulfidiphilus (tsOSHS) exhibited maximum activity at 35°C and pH 6.5. OSHS displayed an excellent thermostability with a half-life of 21.72 h at 30°C. Furthermore, the activity of OSHS increased 115% after Fe2+ added. L-methionine was obtained with a total yield reaching 42.63 g/L under the concentration of O-succinyl-L-homoserine 400 mM (87.6 g/L). These results indicated that OSHS is a potential candidate for applying in the large-scale bioproduction of L-methionine.

Structural insights into the thermostability mechanism of a nitrile hydratase from Caldalkalibacillus thermarum by comparative molecular dynamics simulation.

Nitrile hydratase (NHase), an excellent bio-catalyst for the synthesis of amide compounds, was composed of two heterologous subunits. A thermoalkaliphilic NHase NHCTA1 (Tm = 71.3°C) obtained by in silico screening in our study exhibited high flexibility of α-subunit but excellent thermostability, as opposed to previous examples. To gain a deeper structural insight into the thermostability of NHCTA1, comparative molecular dynamics simulation of NHCTA1 and reported NHases was carried out. By comparison, we speculated that β-subunit played a key role in adjusting the flexibility of α-subunit and the different conformations of linker in "α5-helix-coil ring" supersecondary structure of β-subunit can affect the interaction between β-subunit and α-subunit. Mutant NHCTA1-α6 C with a random coil linker and mutant NHCTA1-αβγ with a truncated linker were therefore constructed to understand the impact on NHCTA1 thermostability by varying the supersecondary structure. The varied thermostability of NHCTA1-α6 C and NHCTA1-αβγ (Tmα6C = 74.4°C, Tmαβγ = 65.6°C) verified that the flexibility of α-subunit adjusted by β-subunit was relevant to the stability of NHCTA1. This study gained an insight into the NNHCTA1 thermostability by virtual dynamics comparison and experimental studies without crystallization, and this approach could be applied to other industrial-important enzymes.

IgY antibodies against Ebola virus possess post-exposure protection in a murine pseudovirus challenge model and excellent thermostability.

Ebola virus (EBOV) is one of the most virulent pathogens that causes hemorrhagic fever and displays high mortality rates and low prognosis rates in both humans and nonhuman primates. The post-exposure antibody therapies to prevent EBOV infection are considered effective as of yet. However, owing to the poor thermal stability of mammalian antibodies, their application in the tropics has remained limited. Therefore, a thermostable therapeutic antibody against EBOV was developed modelled on the poultry(chicken) immunoglobulin Y (IgY). The IgY antibodies retaining their neutralising activity at 25°C for one year, displayed excellent thermal stability, opposed to conventional polyclonal antibodies (pAbs) or monoclonal antibodies (mAbs). Laying hens were immunised with a variety of EBOV vaccine candidates and it was confirmed that VSVΔG/EBOVGP encoding the EBOV glycoprotein could induce high titer neutralising antibodies against EBOV. The therapeutic efficacy of immune IgY antibodies in vivo was evaluated in the newborn Balb/c mice who have been challenged with the VSVΔG/EBOVGP model. Mice that have been challenged with a lethal dose of the pseudovirus were treated 2 or 24 h post-infection with different doses of anti-EBOV IgY. The group receiving a high dose of 106 NAU/kg (neutralising antibody units/kilogram) showed complete protection with no symptoms of a disease, while the low-dose group was only partially protected. Conversely, all mice receiving naive IgY died within 10 days. In conclusion, the anti-EBOV IgY exhibits excellent thermostability and protective efficacy. Anti-EBOV IgY shows a lot of promise in entering the realm of efficient Ebola virus treatment regimens.

Biphasic organohydrogels based on phase change materials with excellent thermostability for thermal management applications

Abstract Innovative thermal management materials are in high demand for construction of energy-efficient systems. Evaporative cooling hydrogel has been extensively investigated in passive building cooling owing to its cost-effective and environmental-friendly characteristics. However, poor mechanical properties and shape instability severely restrict its scope and lifespan. In this study, we report an ingenious and effective thermal management material, the PCMs organohydrogel, with advanced thermal performance and outstanding shape and thermal stability, which integrates the advantages of evaporative cooling performance of water and latent heat storage capability of eicosane. The biphasic PCMs organohydrogel was synthesized by the CAA-HRP-H2O2 ternary enzyme-mediated polymerization of the eicosane-in-water emulsion stabilized by the cellulose acetoacetate (CAA). CAA played important roles in the system not only as the emulsifier but also as the polymerization mediator. The encapsulation of PCMs by the organohydrogel provides the composites outstanding thermal stability as the decomposition temperature of the eicosane was elevated by 101 °C. Furthermore, the PCMs organohydrogel exhibits excellent thermomechanical performance and shape memory effect because of the wrapped phase-transition micro-inclusions and the interfacial tension of heterophases. The application of the PCMs organohydrogel as passive cooling material on the model house roof was demonstrated. The cooling effectiveness of the PCMs organohydrogel was investigated, indicating that the biphasic PCMs organohydrogel is expected to be an efficient and reliable passive thermal management material in building thermoregulations.

Two-Dimensional Carbonitride MXenes as an Efficient Electrocatalyst for Hydrogen Evolution

Owing to their excellent thermostability, superior electrical conductivity, and tunable surface chemistry, two-dimensional transition-metal carbides, nitrides, and carbonitrides (MXenes) are highly...

Enhanced dielectric properties and thermostability in polyimide composites with core-shell structured polyimide@BaTiO3 nanoparticles

Polymer composites with high dielectric constant and thermal stability have shown great potential applications in the fields relating to the energy storage. Herein, core-shell structured polyimide@BaTiO3 (PI@BT) nanoparticles were fabricated via in-situ polymerization of poly(amic acid) (PAA) and the following thermal imidization, then utilized as fillers to prepare PI composites. Increased dielectric constant with suppressed dielectric loss, and enhanced energy density as well as heat resistance were simultaneously realized due to the presence of PI shell between BT nanoparticles and PI matrix. The dielectric constant of PI@BT/PI composites with 55 wt% fillers increased to 15.0 at 100 Hz, while the dielectric loss kept at low value of 0.0034, companied by a high energy density of 1.32 J·cm−3, which was 2.09 times higher than the pristine PI. Moreover, the temperature at 10 wt% weight loss reached 619°C, demonstrating the excellent thermostability of PI@BT/PI composites. In addition, PI@BT/PI composites exhibited improved breakdown strength and toughness as compared with the BT/PI composites due to the well dispersion of PI@BT nanofillers and the improved interfacial interactions between nanofillers and polymer matrix. These results provide useful information for the structural design of high-temperature dielectric materials.

Wood/polyimide composite via a rapid substitution compositing method for extreme temperature conditions

Wood is a common-sense thermostable construction material, but the decrease in its structural stability and mechanical strength due to the degradation of lignin and hemicelluloses limits its practical applications in extreme environments. Here, we synthesize a high-performance wood/polyimide composite via the partial substitution of lignin and hemicellulose with super thermostable polyimide. This method involves the rapid partial removal of lignin and hemicellulose in only 3 min using microwave-assisted deep eutectic solvent (DES) pretreatment and subsequent impregnation of polyimide into the pretreated wood. The microwave-assisted DES pretreatment greatly reduced the processing time for lignin and hemicellulose extraction, while preserving the natural cellular scaffold of wood and opening more channels for polyimide infiltration. The obtained wood/polyimide composite showed a 17% improved Young's modulus and a 63% higher dynamic storage modulus than natural wood. The temperature of the first maximum decomposition rate of the wood/polyimide composite significantly increased to 290 °C due to the infiltration of the thermostable polyimide. Furthermore, the wood/polyimide composite exhibited a smoke suppression property (33% decrease), and the time to produce smoke was delayed by 200 s. Our work provides a rapid pretreatment method for wood and a substitution compositing method to produce wood-framed polyimide composites with excellent thermostability.

Nanobody-Based Indirect Competitive ELISA for Sensitive Detection of 19-Nortestosterone in Animal Urine.

Nanobody (Nb), a new type of biorecognition element generally from Camelidae, has the characteristics of small molecular weight, high stability, great solubility and high expression level in E. coli. In this study, with 19-nortestosterone (19-NT), an anabolic androgenic steroid as target drug, three specific Nbs against 19-NT were selected from camel immune library by phage display technology. The obtained Nbs showed excellent thermostability and organic solvent tolerance. The nanobody Nb2F7 with the best performance was used to develop a sensitive indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for 19-NT detection. Under optimized conditions, the standard curve of ic-ELISA was fitted with a half-maximal inhibitory concentration (IC50) of 1.03 ng/mL and a detection limit (LOD) of 0.10 ng/mL for 19-NT. Meanwhile, the developed assay had low cross- reactivity with analogs and the recoveries of 19-NT ranged from 82.61% to 99.24% in spiked samples. The correlation coefficient between ic-ELISA and the ultra-performance liquid chromatography/mass spectrometry (UPLC-MS/MS) method was 0.9975, which indicated that the nanobody-based ic-ELISA could be a useful tool for a rapid analysis of 19-NT in animal urine samples.

Microstructure and Mechanical Properties of an Austenitic Heat-Resistant Steel after Service at 570\xa0\xb0C and 25.4\xa0MPa for 18\xa0Years

Microstructure and mechanical properties of an austenitic heat-resistant steel (12Cr18Ni12Ti) serviced in a supercritical power plant at 570 °C/25.4 MPa for 160,000 h were investigated. The results show that the hardness and the tensile strength did not decrease; however, the impact toughness was remarkably reduced. The TiC precipitate shows excellent thermostability; for example, it hardly grew up, and no big M23C6 carbides were found. However, large Fe, Cr-rich σ-phase was doomed to precipitate along grain boundary, which should be responsible for the reduced toughness. The growth of σ-phase was observed to have an interaction with the preexisted carbides.

Recent advance in hollow-core fiber high-temperature and high-pressure sensing technology [Invited

The pure-silica hollow-core fiber (HCF) has excellent thermostabilities that can benefit a lot of high-temperature sensing applications. The air-core microstructure of the HCF provides an inherent gas container, which can be a good candidate for gas or gas pressure sensing. This paper reviews our continuous efforts to design, fabricate, and characterize the high-temperature and high-pressure sensors with HCFs, aiming at improving the sensing performances such as dynamic range, sensitivity, and linearity. With the breakthrough advances in novel anti-resonant HCFs, sensing of high temperature and high pressure with HCFs will continuously progress and find increasing applications.

Fluoroarene derivative based passivation of perovskite solar cells exhibiting excellent ambient and thermo-stability achieving efficiency &gt;20%

Trap states in perovskite thin films were passivated effectively by pentafluoroaniline (PFA) additive, thereby significantly enhancing the photovoltaic performances as well as the overall device stability.

Aluminum-based metal-organic frameworks (CAU-1) highly efficient UO22+ and TcO4− ions immobilization from aqueous solution

In this research, an Al-based metal-organic framework (MOFs), CAU-1 was prepared through complexation between 2-aminoterephthalic acid and Al (III) by solvothermal approach, and simple operation and cost-effective synthetic route. The objective was to immobilize the typical positive/negative radionuclide ions (UO22+/TcO4−) in aqueous solution. The synthesized CAU-1 was characterized by XRD, FT-IR, TGA, FESEM, TEM-SAED, pHpzc, XPS and N2 physisorption analysis. The structure of CAU-1 possessed excellent thermostability, rich functional groups (‒NH2 and ‒OH groups), as well as large surface area (1636.3 m2/g) and the micropore volume (0.51 m3/g). Furthermore, batch experiments demonstrated that CAU-1 with superior adsorption capacity was 648.37 (UO22+) mg/g and 692.33 (ReO4−) mg/g calculating from Langmuir isotherm model, respectively. Thermodynamic investigation showed the adsorption process was endothermic and spontaneous. In addition, the adsorption mechanism of ReO4− ion onto CAU-1 could be electrostatic attraction and chelation effect, while for UO22+ ion, was mainly chelation effect induced by nitrogen-containing and oxygen-containing functional groups. Hence, the inexpensive and high-capacity CAU-1 could be considered as a practical material for sequestrations of radioactive pollutants from water environment.