Enhanced Mechanical and Acoustic Properties of Basalt Fiber/Polyurethane Composites by Silane Coupling Agents.

Modified basalt microfiber-reinforced polyurethane elastomer composites were prepared by a semi-prepolymer method with two different silane coupling agents (KH550 and KH560) in this study. Infrared spectroscopy was used to quantify the degree of microphase separation and analyze the formation of hydrogen bonding in polyurethane. The interfacial surface and the morphology of fibers and composites from tensile fracture were examined by a scanning electron microscope.

Chemodynamic covalent adaptable network-induced robust, self-healing, and degradable fluorescent elastomers for multicolor information encryption.

Elastomers are of great significance in developing smart materials for information encryption, and their unique self-healing and highly flexible properties provide innovative solutions to enhance security and anti-counterfeiting effectiveness. However, challenges remain in the multifunctional combination of mechanical properties, self-healing, degradability, and luminescence of these materials. Herein, a chemodynamic covalent adaptable network (CCAN)-induced robust, self-healing, and degradable fluorescent elastomer is proposed.

A dual-nucleophilic ester-induced supramacromolecular fire-proof hydrogel coating for protecting polymers.

Polymer materials are highly vulnerable to fire disaster. However, current research focuses on flame retardancy rather than protection. In this work, two natural extracts of phytic acid (PA) and tannic acid (TA), were successfully compounded via dual-nucleophilic esterification, which facilitated the formation supramolecular hydrogel (T-P-PAA).

Improvement of Mechanical and Acoustic Characteristics of Halloysite Nanotube-Reinforced Polyurethane Elastomer Composites and Their Applications.

Polyurethane incorporated with nanofillers such as carbon nanotubes, basalt fibers, and clay nanoparticles has presented remarkable potential for improving the performance of the polymeric composites. In this study, the halloysite nanofiller-reinforced polyurethane elastomer composites were prepared via the semi-prepolymer method. The impact of different halloysites (halloysite nanotubes and halloysite nanoplates) in polyurethane composites was investigated.

Sustainable Cathodic Performances of VS in Rechargeable Magnesium Batteries by Cobalt Substitution.

Vanadium tetrasulfide (VS) is one of the most promising cathodic materials for rechargeable magnesium battery systems (RMBSs). Elemental substitution to expand layers, creation of sulfur vacancies, and reduction of particle sizes of VS are undoubtedly effective strategies to enhance cathodic performances. Experimental and DFT analysis revealed that valence states of vanadium and cobalt have been elevated from V to V and Co to Co in VS and that the Co-S bond length shortened due to cobalt substitution, which resulted in enhanced overall internal polarization in the layered atomic structure of VS by increasing cobalt concentrations.

One-Pot Etching Pyrolysis to Defect-Rich Carbon Nanosheets to Construct Multiheteroatom-Coordinated Iron Sites for Efficient Oxygen Reduction.

Constructing multiheteroatom coordination structure in carbonaceous substrates demonstrates an effective method to accelerate the oxygen reduction reaction (ORR) of supported single-atom catalyst. Herein, the novel etching route assisted by potassium thiocyanate (KCNS) is developed to convert metal-organic framework to 2D defect-rich porous N,S-co-doped carbon nanosheets for anchoring atomically dispersed iron sites as the high-performance ORR catalysts (Fe-SACs). The well-designed KCNS-assisted etching route can generate spatial confinement template to direct the carbon nanosheet formation, etching condition to form defect-rich structure, and additional sulfur atoms to coordinate iron species.

Energetic and Protective Coating via Chemical and Physical Synergism for High Water-Reactive Aluminum Powder.

Aluminum powder plays important role in the field of energetic materials. However, it is often vulnerable to oxygen and water due to the high reactivity of aluminum, and it is challenging to build up uniform and passivated coating via existing means. In this work, (Heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane (FAS-17) and glycidyl azide polymer (GAP) were used to coat the surface of high water-reactive aluminum powder (w-Al) to form inactivated w-Al@FAS-17@GAP energetic materials, via the synergy of chemical bonding and physical attraction.

Curing Kinetics of Methylene Diphenyl Diisocyanate-Based Polyurethane Elastomers.

The curing kinetics of MDI-based polyurethane elastomers were studied by non-isothermal differential scanning calorimetry (DSC). The kinetic parameters of the reaction system were calculated by the Kissinger method. The changing activation energy was observed by the Flynn−Wall−Ozawa method and the Friedman method.

Enhanced Hydrogen Generation Performance of Al-Rich Alloys by a Melting-Mechanical Crushing-Ball Milling Method.

The main problem for the application of hydrogen generated via hydrolysis of metal alloys is the low hydrogen generation rate (HGR). In this paper, active Al alloys were prepared using a new coupled method-melting-mechanical crushing-mechanical ball milling method to enhance the HGR at room temperature. This method contains three steps, including the melting of Al, Ga, In, and Sn ingots with low melting alloy blocks and casting into plates, then crushing alloy plate into powders and ball milling with chloride salts such as NiCl and CoCl were added during the ball milling process.

Non-Isothermal Crystallization Kinetics of Poly(ethylene glycol) and Poly(ethylene glycol)-B-Poly(ε-caprolactone) by Flash DSC Analysis.

The non-isothermal crystallization behaviors of poly (ethylene glycol) (PEG) and poly (ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) were investigated through a commercially available chip-calorimeter Flash DSC2+. The non-isothermal crystallization data under different cooling rates were analyzed by the Ozawa model, modified Avrami model, and Mo model. The results of the non-isothermal crystallization showed that the PCL block crystallized first, followed by the crystallization of the PEG block when the cooling rate was 50-200 K/s.

Non-Isothermal Crystallization Kinetics of Poly(Ethylene Glycol)-Poly(l-Lactide) Diblock Copolymer and Poly(Ethylene Glycol) Homopolymer via Fast-Scan Chip-Calorimeter.

The non-isothermal crystallization kinetics of double-crystallizable poly(ethylene glycol)-poly(l-lactide) diblock copolymer (PEG-PLLA) and poly(ethylene glycol) homopolymer (PEG) were studied using the fast cooling rate provided by a Fast-Scan Chip-Calorimeter (FSC). The experimental data were analyzed by the Ozawa method and the Kissinger equation. Additionally, the total crystallization rate was represented by crystallization half time .

3D Phase Field Modeling of Multi-Dendrites Evolution in Solidification and Validation by Synchrotron X-ray Tomography.

In this paper, the dynamics of multi-dendrite concurrent growth and coarsening of an Al-15 .% Cu alloy was studied using a highly computationally efficient 3D phase field model and real-time synchrotron X-ray micro-tomography. High fidelity multi-dendrite simulations were achieved and the results were compared directly with the time-evolved tomography datasets to quantify the relative importance of multi-dendritic growth and coarsening.

A Novel Lightweight Polyurethane Composite for Application on Ultra-High-Voltage Insulator Core Filler.

This study aimed to prepare a new lightweight ultra-high-voltage insulator core filler composite, which can solve the problem of bulkiness. In this study, rigid polyurethane foam pellets with different densities are used as lightweight fillers and polyurethane resins to compound lightweight composite materials. On accounting for working conditions, the density, insulation, heat resistance, water absorption and mechanical properties are tested.

Effect of the Aromatic Amine Curing Agent Structure on Properties of Epoxy Resin-Based Syntactic Foams.

Epoxy resin is one of the commonly used matrixes of syntactic foams as a buoyancy material, the curing agents of which affect some of the properties for syntactic foams. Therefore, the curing reactions of ,,','-tetraepoxypropyl-4,4'-diaminodiphenylmethane (AG-80) epoxy resin between 4,4-diaminodiphenyl methane (DDM) and the mixture of -xylylenediamine and DDM (DDM--XDA) systems are studied. The DDM mixed with -XDA enhances curing reactions with the AG-80 epoxy resin, and the mechanisms of the two curing systems are different through nonisothermal kinetics.

Tetrafunctional Epoxy Resin-Based Buoyancy Materials: Curing Kinetics and Properties.

In order to synthesize a new kind of buoyancy material with high-strength, low-density and low-water-absorption and to study the curing reaction of tetraglycidylamine epoxy resin with an aromatic amine curing agent, the non-isothermal differential scanning calorimeter (DSC) method is used to calculate the curing kinetics parameters of N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane epoxy resin (AG-80) and the m-xylylenediamine (m-XDA) curing process. Further, buoyancy materials with different volume fractions of hollow glass microsphere (HGM) compounded with a AG-80 epoxy resin matrix were prepared and characterized. The curing kinetics calculation results show that, for the curing reaction of the AG-80/m-XDA system, the apparent activation energy increases with the conversion rates increasing and the reaction model is the Jander equation (three-dimensional diffusion, 3D, n = 1/2).

Carbazole-functionalized hyper-cross-linked polymers for CO uptake based on Friedel-Crafts polymerization on 9-phenylcarbazole.

To systematically explore the effects of the synthesis conditions on the porosity of hyper-cross-linked polymers (HCPs), a series of 9-phenylcarbazole (9-PCz) HCPs (-) has been made by changing the molar ratio of cross-linker to monomer, the reaction temperature , the used amount of catalyst and the concentration of reactants. Fourier transform infrared spectroscopy was utilized to characterize the structure of the obtained polymers. The TG analysis of the HCPs showed good thermal stability.

Bacteria-Instructed In Situ Aggregation of AuNPs with Enhanced Photoacoustic Signal for Bacterial Infection Bioimaging.

The emergence of drug-resistant bacteria is becoming the focus of global public health. Early-stage pathogen bioimaging will offer a unique perspective to obtain infection information in patients. A photoacoustic (PA) contrast agent based on functional peptide modified gold nanoparticles (AuNPs@P1) is developed.

Curing and Characteristics of N,N,N',N'-Tetraepoxypropyl-4,4'-Diaminodiphenylmethane Epoxy Resin-Based Buoyancy Material.

Buoyancy material is a type of low-density and high-strength composite material which can provide sufficient buoyancy with deep submersibles. A new buoyancy material with N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane epoxy resin (AG-80) and m-xylylenediamine (m-XDA) curing agent as matrix and hollow glass microsphere (HGM) as the filler is prepared. The temperature and time of the curing process were determined by the calculations of thermal analysis kinetics (TAK) through differential scanning calorimetry (DSC) analysis.

Investigation of the agglomeration reduction mechanism of the aluminized HTPB propellant containing ferric perfluorooctanoate [Fe(PFO)].

In this study, ferric perfluorooctanoate [Fe(PFO)] was used in the aluminized HTPB propellant to reduce Al agglomeration during solid propellant combustion, and the agglomeration reduction mechanism was experimentally demonstrated the burning rate measurement, heat of explosion and Al agglomeration analysis. The behavior of the burning particles on the burning surface as well as the morphology and composition of the quenched burning particles were characterized by microscopic high-speed photography and X-ray photoelectron spectroscopy, respectively; the thermal decomposition properties and gaseous decomposition products of Fe(PFO) were investigated by thermal gravimetry-differential scanning calorimetry joint analysis (TG-DSC), Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS). The results show that Fe(PFO) can significantly increase the burning rate of the aluminized HTPB propellant and reduce Al agglomeration.