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Dihydroxylammonium 5,5′- bistetrazole-1,1′-diolate (TKX-50) was used to prepare TKX-50-based polymer bonded explosive (PBX) for the first time in this study. The thermal stabilities and the kinetic parameters of TKX-50 and TKX-50-based PBX were compared via Differential Scanning Calorimetry (DSC), Thermal Gravity-Differential Thermal Gravity (TG-DTG) and Accelerating Rate Calorimeter (ARC). Furthermore, in order to know about their thermal safeties comprehensively, an advanced thermal analysis program based on Friedman method was employed to calculate the thermal safety parameters for TKX-50 and its PBX. With its help, two important safety parameters (time to maximum rate under adiabatic conditions ( TMR ad ) and self-accelerating decomposition temperature ( SADT )) for the two energetic materials were calculated and discussed. Finally, based on the safety parameters, effects of storage conditions and ambient temperatures on the thermal explosions of TKX-50 and TKX-50-based PBX were further studied by using finite element analysis (FEA). [ABSTRACT FROM AUTHOR]

Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) is a newly synthesized energetic material with excellent comprehensive properties. Cyclotrimethylenetrinitramine (RDX) is currently one of the most widely used energetic materials in the world. TKX-50 and RDX supercell models and TKX-50/RDX cocrystal model were constructed based on their crystal cell parameters and the formation mechanism of cocrystal, respectively, then they were simulated by molecular dynamics (MD) simulations. The maximum trigger bond (N NO 2 ) length(L max ), binding energy (E bind ), radial distribution function (RDF), cohesive energy density(CED) and mechanical properties were simulated at different temperatures based on the simulated equilibrium structures of the models. The simulated results indicate that hydrogen bond and van der Waals force interactions exist in the cocrystal system and the hydrogen bonds are mainly derived from the hydrogen atom of TKX-50 with the oxygen or nitrogen atom of RDX. Moreover, TKX-50/RDX cocrystal structure significantly reduces the sensitivity and improves the thermodynamic stability of RDX, and it also shows better mechanical properties than pure TKX-50 and RDX, indicating that it will vastly expand the application scope of the single compound explosives. [ABSTRACT FROM AUTHOR]

A simple naphthalene based chemosensor was designed as a quantitatively operating lab-on-a-molecule for the selective detection of fluoride, cyanide and nitroaromatic explosives, showing significant emission quenching and absorption enhancement in dual channel along with a distinct solution color change. In addition, the sensing mechanism was evaluated by NMR titration and fluorescent titration. [ABSTRACT FROM AUTHOR]

A simple dual sensing of CN − and Ag + was first time reported by naphthalene based lab-on-a-molecule containing benzothiazole in DMF buffered aqueous solution. With CN − and Ag + , probe 1 showed highly selective and sensitive responses towards CN − and Ag + in both UV–Vis and fluorescence channels over other tested ions. Meanwhile, the sensing mechanism of both title ions was further studied by NMR titration and XPS experiments. [ABSTRACT FROM AUTHOR]

[Display omitted] • The TETA-PAO/GF electrode material was prepared by a simple and green method. • The TETA-PAO/GF electrode material exhibits excellent electrocatalytic reduction of U(VI) under electric field conditions. • The TETA-PAO/GF electrode material has good selectivity and reusability. • The TETA-PAO/GF electrode material can electrocatalytically reduce U(VI) in real seawater under electric field conditions. The amidoxime-based material is one of the effective materials for adsorbing uranium. The electrocatalysis can be used as an effective strategy for separating uranium. In this study, conductive graphite felt was used as substrate, amine-amidoxime modified polyacrylonitrile (PAN) graphite felt was prepared by heterogeneous method. With the successful synthesis of the material with bifunctional groups, the bifunctional modified PAN graphite felt (TETA-PAO/GF) had good uranium adsorption performance by the way of electrocatalysis technology. It was characterized by SEM, FT-IR, XPS, XRD, ICP-MS, etc. The adsorption capacity of the electrode material to uranium reached 1 142 mgU·g−1 in unsaturated state in 1 000 mg·L-1 spiked seawater. In real seawater adsorption experiment, 90.08 % uranium was extracted from 16 L seawater. Ultimately, the assessment of the reusability and ion selectivity of TETA-PAO/GF revealed that it has a certain use value for uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

The abrasive wear tests were performed on the prepared SiC p –Sialon composite refractories with quartz particles as abrasives. The study aims to explore the effects of load and wear time on wear loss of SiC p –Sialon composite refractories as well as the mechanism of material removal. SiC p –Sialon composite refractories prepared by nitriding reaction sintering consisted of α-SiC, β-Si 3 N 4 , and Si 4 Al 2 O 2 N 6 . The wear loss of SiC p –Sialon composite refractories increased significantly with the increases in test load and test time. The primary wear mechanism of SiC p –Sialon composite refractories is micro-cutting. The mechanism of material removal mainly involves the matrix. The micro-cutting occurred firstly in the matrix and caused the loss of the matrix. Without the protection from the surrounding matrix, the SiC aggregates were eventually stripped. [ABSTRACT FROM AUTHOR]

The conventional electrospinning process for the preparation of fibers usually require complex equipment and complicated preparation processes, as well as chemical crosslinkers and organic solvents, which limits its application in the preparation of biomedical materials. In the current study, carboxymethyl cellulose/N-2-hydroxylpropyl trimethyl ammonium chloride chitosan (CMC/HACC) composite fibers were fabricated by polyelectrolyte complexation (PEC) and freeze drying coupled method in both pure water and NaCl solution. The structures of the as-prepared fibers and the effects of NaCl concentration on the structures of fibers were studied by FTIR, solid 13C NMR, XRD, XPS and SEM. The formation mechanism of the composite fiber and the effects of NaCl concentration on structure and properties of the composite fiber were simulated in the Materials Studio software and discussed. The swelling properties and the thermal decomposition kinetics of the composite fiber were studied. The results suggest that the addition of NaCl electrolyte to the complexing system significantly affects the structure and properties of the PEC fiber. Our work has provided a new preparation route to the composite fibers of natural polymers with controllable structures and properties by the combination of PEC and freeze drying techniques using NaCl with desired concentration as the electrolyte. • CMC/HACC composite fibers were prepared by PEC-freeze drying coupled method; • MS simulation was used to discuss formation mechanism of the PEC fibers; • Adding of electrolyte affects the structure and properties of the PEC fiber; • The route to prepare controllable PEC fibers was explored. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA) and dibutyl phthalate (DBP) binary system was simulated by molecular dynamics (MD) simulations with the COMPASS force field to predict properties of PMMA/DBP blends such as the miscibility, the glass transition temperature ( T g ) and mechanical properties of polymer/plasticizer blends. Results show that PMMA/DBP is a miscible system, which can be predicted by comparing the difference of the solubility parameters value (|Δ δ |<2.0 MPa 0.5 ) between PMMA and DBP. The free volumes ( V F ) and density ( ρ ) of PMMA/DBP system were simulated to study the T g . It is found that the V F and ρ of PMMA/DBP change regularly along with the increase of DBP mass fraction and the transition occurred at the turning point. We also predicted the effects of temperature and DBP on the mechanical properties of PMMA including Young's modulus ( E ), Bulk modulus ( K ), Shear modulus ( G ) and Poisson's ratio ( v ). The mechanical properties can be effectively improved by the temperature and the addition of DBP plasticizer, which may provide a more flexible mixture with a lower E , K , G and an increased ductility. Accordingly, the method used in this work is not only a useful tool to provide properties of a given polymer/plasticizer blend but also a promising technique to help screen the formulations of polymer bonded explosive (PBX) and propellants before experiments. [ABSTRACT FROM AUTHOR]

A derivative of squaramide (cyclobuta[b]quinoxaline-1, 2(3H, 8H)-dione) has been synthesized for the ratiometric and colorimetric sensing of F − in aqueous solution in competitive fashion. With F − , probe 1 showed a highly selective naked-eye detectable color change along with a characteristic UV–Vis absorbance over other tested ions, which probably originates from the deprotonation occurred between 1 and F − , as proved by the 1 H NMR titration experiments and DFT calculations. [ABSTRACT FROM AUTHOR]

Hydrophobic AlCoCrFeNi high-entropy alloy (HEA) was prepared by electrochemical dealloying using 5% of weight percent H 2 SO 4 aqueous solution at low temperature. The results of energy-dispersive spectrometer (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the element contents of Al and Ni were greatly reduced after dealloying treatment, leading to the increase of body centered cubic (BCC, Fe-Cr) phase and consequently, the achievement of the protective barrier of Cr- enriched oxide film on the substrate surface. The static water contact angle increased with the extension of dealloying period and reached a maximum value of 127 ± 1°, showing pronounced hydrophobic performance after dealloying treatment. Meanwhile, the AlCoCrFeNi HEA specimens showed excellent mechanical properties involved compressive strength and micro-hardness. Compared with the as-cast AlCoCrFeNi HEA, the HEA specimens after dealloying treatment exhibited superior corrosion resistance in an acidic aqueous solution of 3-nitro-1, 2, 4-triazole-5-one (NTO) aqueous solutions confirmed by potentiodynamic polarization tests and electrochemical impedance spectra (EIS) analyses, which was credited to the Cr- and Fe- enriched oxide and hydrophobic surface. The raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study. [Display omitted] • Hydrophobic AlCoCrFeNi HEAs with superior corrosion resistance were prepared. • Aggregation of nanoscale rod-like particles enhance the surface hydrophobicity. • Structures with the "lotus effect" were found to prevent detection of H 2 O and NTO. • The protective barrier of Cr-rich oxides against NTO aqueous solution was proved. [ABSTRACT FROM AUTHOR]

Solid particle erosion wear tests were performed on the prepared SiC–Si 3 N 4 composite ceramic at elevated temperatures using sharp SiC particles with the diameter of 325–830 µm. The study aims to explore the effects of erosion temperature and impingement angle on the high temperature erosion resistance of SiC–Si 3 N 4 composite ceramic. The phase compositions of SiC–Si 3 N 4 composite ceramic prepared by nitriding reaction sintering consisted of α-SiC, β-Si 3 N 4 , Si 2 N 2 O and Si. The volume erosion rate of SiC–Si 3 N 4 composite ceramic increases firstly and then decreases with the increase of the erosion temperature, while it increases gradually as increasing the impingement angle. The minimum volume erosion rate was obtained at the erosion temperature of 1400 °C and the impingement angle of 30°. The removal of materials at low erosion temperatures is mainly caused by brittle fracture and stripping of aggregates which are due to lose the protection from the matrix. The primary erosion mechanisms of SiC–Si 3 N 4 composite ceramic at high temperatures are ascribed to plastic deformation and oxidation protection. [ABSTRACT FROM AUTHOR]

Pd/mpg-C 3 N 4 was prepared by depositing palladium nanoparticles on mpg-C 3 N 4 using chemical reduction method, and was firstly used for the catalytic hydrogenolysis of HBIW in hydrogen under atmosspheric pressure. Due to the unique "nitrogen ring" and the larger specific surface area of the mpg-C 3 N 4 , Pd/mpg-C 3 N 4 showed a better performance than Pd/C and the unprecedented recyclability in the conversion of HBIW to TADBIW. Such results do not only promote the application of HNIW but also enlighten the design of heterogeneous catalysts for hydrodebenzylation. [Display omitted] • Although Pd/mpg-C 3 N 4 was widely applied in hydrogenation, it was reported in the catalytic hydrogenation of debenzylation for the first time. • Pd/mpg-C 3 N 4 exhibited higher performance than Pd/C in the hydrodebenzylation of HBIW in terms of both recyclability and the activity. • Pd/mpg-C 3 N 4 displayed the unprecedented recyclability in the conversion of HBIW into TADBIW, which is significant for the application of HNIW. The low stability and poisoning of the palladium-based catalysts in the debenzylation of HBIW elevated the cost of the hydrogenolysis, and thus restricted the application of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW). To address this problem, Pd/mpg-C 3 N 4 was prepared by depositing palladium nanoparticles on mesoporous graphite carbon nitride (mpg-C 3 N 4), and used for the catalytic hydrogenolysis in the conversion of HBIW to TADBIW under the atmospheric pressure. After optimizing the reaction condition and the usage amount, the highest yield of 81.7 % was obtained at 45℃ after reaction for 8 h when the ratio of palladium to HBIW was 1%. A yield of 74 % was obtained when the ratio of palladium to HBIW was 0.4 %. More importantly, Pd/mpg-C 3 N 4 can be recycled unprecedently for three times in the conversion of HBIW to TADBIW while preserving the reasonable activity. Such results should benefit for promoting the application of HNIW and also the design of the heterogeneous catalysts for hydrodebenzylation. [ABSTRACT FROM AUTHOR]

• Controllable and stable physical hydrogel based on chitosan was prepared. • Compositing of polyacrylate improved the swelling and adsorption properties. • Graphene oxide enhanced mechanical and adsorption properties of the hydrogel. • The products showed properties of adjustable polyampholyte hydrogel. • The composite hydrogel could simultaneously adsorb cationic and anionic dye. In the current study, a novel CTS/PAA/GO composite polyampholyte physical hydrogel was prepared by the SD-A-SGT method to achieve desired adsorption properties for printing and dyeing wastewater treatment. The hydrogels exhibited controllable and stable structure. The linear PAA significantly improved the swelling and adsorption properties of the hydrogel, and the composition of GO enhanced its mechanical and adsorption properties. The batch adsorption experiments revealed the ability to simultaneously absorb the cationic model dye, MB, and anionic model dye, FY3, with the similar equilibrium adsorption capacities of 296.5±31.7 mg·g−1 and 280.3±23.9 mg·g−1, respectively. The factors affecting the dye adsorption performance, including the hydrogel composition, initial dye concentration and dye solution pH, were investigated. The dye adsorption kinetics was studied and the adsorption mechanisms were proposed. The unique structure and properties of the hydrogel make it a great candidate adsorbent for wastewater treatments. [ABSTRACT FROM AUTHOR]