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In this study, a shear-stiffening composite porous material (PU@CS) was developed using the dipping-drying technique, with polyurethane (PU) as the substrate. PU@CS not only overcomes the cold flow drawbacks of shear-stiffening gel (SSG) but also significantly enhances the mechanical properties of PU (with a one-order-of-magnitude increase in maximum storage modulus). The introduction of multi-walled carbon nanotubes (MWCNTs) overcomes the electrostatic aggregation drawback of PU. Due to its outstanding shear hardening effect, PU@CS exhibits superior explosion-proof compared to PU, and when filled to a length of 50 cm, it achieves complete quenching of hydrogen gas explosion flames, with a maximum explosion overpressure attenuation ratio of 87.2%. This work provides data support for the application of SSG in the field of explosion protection. [Display omitted] • Shear stiffening gel was applied in the explosion-proof for the first time. • The shear-stiffening composite explosion-proof material was prepared. • PU@CS has excellent antistatic properties and its explosion-proof mechanism is revealed. [ABSTRACT FROM AUTHOR]

Abstract A novel multi-component powder inhibitor was prepared by mixing conventional suppressants (ammonium polyphosphate and aluminium hydroxide) with porous kaolinite. The inhibition performance of this developed inhibitor was investigated using a 20-L spherical experimental explosion system. The explosion parameters, such as the maximum explosion pressure, maximum pressure rising rate, and time to peak explosion pressure, were obtained to evaluate the suppression effects. The results show that the multi-component inhibitor exhibits higher suppression performance than the single components. The thermal stability, decomposition behavior, and gaseous products were investigated using thermogravimetric analysis, differential scanning calorimetry, and thermogravimetric-mass spectrometry. The inhibition mechanisms are illustrated using physical and chemical explanations. The current work introduces a new gas explosion inhibitor with high performance resulting from the synergistic effect between its ingredients. Graphical abstract Inhibition mechanisms of the multi-component powder are investigated by explosion experiments and thermal decomposition analysis. Unlabelled Image Highlights • Inhibitor is prepared by mixing porous mineral with conventional suppressants. • Excellent explosion inhibition efficiency is achieved for this powder inhibitor. • Inhibition mechanisms of the multi-component inhibitor are investigated. [ABSTRACT FROM AUTHOR]

This work explores the feasibility of using graphene as an effective synergist for intumescent flame retardant (IFR). The flammability test and fire behavior under different fire scenarios are investigated. The incorporation of graphene results in different responses of IFR/polypropylene (PP) composites to small fire tests and burning under forced-flaming condition. The addition of graphene weakens the reaction of flame retardant PP to small flame. Lower loading of graphene is observed to improve the swelling of char, resulting in better insulation of the char and decrease in heat and smoke release. The further increase of graphene leads to the worsened fire safety. Flame retardant mechanism and model are proposed on the basis of the analyses of thermal decomposition products and process, and melt viscosity change. This works provides a solution to comprehensively assess the synergistic or antagonistic effect of graphene, and will be beneficial to developing its flame retardant mechanism. [ABSTRACT FROM AUTHOR]

Artificial nacre-like inorganic-organic hybrid films are fabricated by a facile evaporation-induced self-assembly method using graphene oxide (GO) nanosheets as rigid bricks and a natural polysaccharide of sodium alginate (SA) as soft mortar. To further improve tensile mechanical properties of the GO/SA films, Ca 2 + is utilized as a substitute for the most widely used glutaraldehyde to crosslink the films. Owing to the high chelation affinity for metal ions, the Ca 2 + modified (Ca-GO/SA) films show higher tensile mechanical properties than those of the original samples. Water uptake in the Ca-GO/SA film is greatly decreased and water stability is improved by the introduction of Ca 2 + . The Ca-GO/SA films exhibit water-triggered shape recovery behavior. The films show two-way shape memory effect and possess two original shapes, which can be reversibly transformed by immersion in water and removal of the absorbed moisture. This advanced hybrid film will broaden the applications for biomimetic materials and shows potential for applications in the fields of water-sensitive actuators and sensors. [ABSTRACT FROM AUTHOR]

B, N- and P, N-doped reduced graphene oxide (RGO) are prepared through high temperature annealing method using boric acid and phosphoric acid as the B and P sources, respectively. The synthesized RGO and dual-doped RGO are well characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The heteroatoms are found to be introduced into the graphene structure. The low level of doping (approximately 1.10 at%) exhibits significant improvement in thermal oxidative stability of RGO. In comparison with neat RGO, the temperature at maximum weight loss rate of B-RGO and P-RGO increase by as much as 52 °C and 130 °C, respectively. The mechanism for retarding RGO oxidation by B/P doping is clearly proposed. More stable bond configurations are formed in the B/P-doped RGO. The doped B and P atoms reduce the reactivity of carbon active sites and inhibit the carbon gasification. This work will provide an understanding of thermal oxidative stability of heteroatoms-doped RGO, and offer a strategy for fabricating graphene with elevated temperature applications. [ABSTRACT FROM AUTHOR]

Abstract: Multifunctional designs of biomimetic layered materials are in great demand for broadening their applications. Artificial hybrid films are fabricated using a simple evaporation-induced assembly method, using nacre as the structural model, two-dimensional reduced graphene oxide (RGO) and magnetic graphene (MG) as inorganic building blocks and poly(vinyl alcohol) (PVA) as glue. The nacre-like films exhibit good mechanical performance, such as high stiffness, strength and toughness. The biomimetic materials possess the shielding properties of electromagnetic pollution. MG based nacre-like films present more significant electromagnetic interference (EMI) shielding performance than RGO film, because of a synergism between dielectric loss of graphene and magnetic loss of magnetic nanoparticles. Average EMI shielding effectiveness (SE) reaches ∼20.3dB over the frequency range of 8.2–12.4GHz (X band) for MG hybrid film only 0.36mm thick. The lightweight, flexible and thin MG artificial hybrid films possess good potential for EMI shielding applications. [Copyright &y& Elsevier]

Highlights: [•] Graphene was prepared via a novel and facile solvothermal reduction method for graphite oxide. [•] Most of the oxygen functional groups of graphite oxide were removed. [•] The reduced graphene oxide obtained was featured with bilayer nanosheets. [Copyright &y& Elsevier]

• Thermokinetic suppression of APP powder on sucrose dust deflagration is researched. • Decomposition products of APP have a composite weakening effect on reaction exotherm. • Crosslinking reaction of PPA catalyzes the formation of more and dense carbon layer. • Suppression mechanisms of sucrose dust deflagration by APP powder is investigated. In this investigation, ammonium polyphosphate (APP) is applied to suppress the deflagration of sucrose dust. Through the systematic research on flame propagation images and temperature, decomposition behavior of powder samples and the compositions of deflagration residue, the suppression performance and mechanism of APP on sucrose deflagration are profoundly summarized. Timing diagrams show that APP contributes to reduce deflagration flame brightness, increases ignition delay time and flame fault area. The minimum inerting concentration of APP for sucrose deflagration is determined to be 8 %. From the collected deflagration flame temperature curves, it is confirmed that APP can delay peak temperature arrival time, weaken temperature fluctuation, and decrease peak values of flame temperature and temperature rising rate. Through the analysis on thermal decomposition of samples and deflagration residue, it is reflected that APP has superior composite suppression effect. It can not only absorb reaction heat, but also decrease deflagration exotherm to improve thermal stability of sucrose particles. Thus, the easily oxidized components in sucrose are protected, and deflagration intensity is effectively weakened. This work provides a new solution for prevention and suppression deflagration of dust waste in sugar industry. [ABSTRACT FROM AUTHOR]

• A novel and sensitive fire early alarm was designed based on GO-BA composite paper. • The sensitivity and stability of this novel alarm was excellent. • Flame alarm mechanism of GO-BA paper was described. Boric acid-modified graphene oxide (GO-BA) paper is prepared by a green and facile water evaporation-induced self-assembly method, and its application as an early fire-alarm sensor is investigated. The nacre structure is constructed by assembling graphene oxide (GO) and boric acid (BA) as brick and mortar, respectively. Compared with pure GO paper, improved thermal-oxidative stability is obtained for GO-BA. GO nanosheets are bonded with BA molecules by forming hydrogen bonds between hydroxyl in BA and the rich oxygen-containing functional groups on GO. Notably, the insulating GO-BA paper can be rapidly thermally reduced to conductive reduced graphene oxide under flame exposure, thus providing an ideal fire-alarm response with a quick flame-detection time of ∼0.8 s. In addition, boron oxide formed under flame attack covers the surface of GO, inhibiting further oxidation of GO paper, and effectively extending the duration time of GO-BA under combustion. These results indicate that the GO-BA paper prepared has a broad prospect in the field of fire early-alarm. [ABSTRACT FROM AUTHOR]

Electrical fire is the most frequently occurred fire accident, and fire sensors with self-cutting and ultrasensitive fire-alarm response capability are urgent to be designed and developed. Herein, conductive reduced graphene oxide paper (RGOP) with hierarchical structure is prepared by a facile evaporation-assisted self-assembly of graphene oxide (GO) dispersion and then reduction by hydrazine hydrate vapor. The oxidative decomposition of RGOP containing sodium chloride (RGOP-NaCl) is promoted by the addition of NaCl. When being exposed to flame, RGOP-NaCl strips are readily ruptured. Based on this distinctive self-cutting performance of RGOP-NaCl under fire attacking, a novel fire detection and alarm device is designed by establishing controlling and operation circuits. Under fire encountering, an ultrafast warning response (approximately 5.3 s) of RGOP-NaCl is triggered. Fire-alarm time of RGOP-NaCl is adjustable by varying the content of NaCl. Furthermore, this RGOP-NaCl has the function of fuse and can cut off the conductive circuit timely under fire attacking. This finding will provide a novel thought for the design of advanced fire-alarm sensor and will also expand the application of graphene paper. Image 1 • Conductive RGOP-NaCl is prepared by evaporation-induced self-assembly method. • This RGOP-NaCl exhibits ultrasensitive fire-warning response. • RGOP-NaCl has the function of fuse and self-cutting performance under fire attack. [ABSTRACT FROM AUTHOR]

Organically modified ammonium polyphosphate (APP) flame retardant is prepared by supramolecular assembly method using melamine formaldehyde (MF) resin and phytic acid (PA) as building blocks. Surface characteristics of APP are modified, resulting in the enhancements in water resistance, dispersion in the polymer matrix and their compatibility. This supramolecular assembly modified APP (APP@MF-PA) matches well with charring-foaming agent (CFA) to achieve excellent fire safety for polypropylene (PP), and the superiority over conventional APP is observed. Heat, CO and CO 2 releases of PP are greatly decreased by the intumescent flame retardant (IFR) formulation containing APP@MF-PA and CFA. The modification of APP with MF-PA supramolecules are beneficial to improve the yield, insulation properties, graphitization degree and compactness of char. Flame-retardant mechanisms are demonstrated according to the investigations on gaseous and condensed phase products. This novel and facile modification method provides a new strategy for improving the flame-retardant efficiency of IFR. Image 1 • The surface characteristics of APP were modified by supramolecular assembly. • Fire hazards of PP were greatly reduced by this modified APP and CFA. • Flame retardant mechanisms were proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel inhibitor was synthesized by supramolecular self-assembly. • This inhibitor exhibits a prolonged suppression effect on CH 4 /H 2 /air explosion. • A comprehensive inhibition mechanism is revealed. • By virtue of lotus leaf-like appearance, the hydrophilicity of inhibitors is weakened. A novel inhibitor of PA-MEL@NH 2 -Al 2 O 3 was synthesized by using supramolecular self-assembly technique with phytic acid (PA) and melamine (MEL) as the building blocks. Bauxite is a kind of mining waste, which is abundant in Al 2 O 3 and is used as loading matrix. By right of lotus leaf-like structure, the hygroscopicity of PA-MEL@NH 2 -Al 2 O 3 is greatly weakened. The feasibility of inhibiting CH 4 /H 2 /air explosion by different concentrations of PA-MEL@NH 2 -Al 2 O 3 was explored in a 20 L Spherical explosive vessel. The optimum inhibitory effect is obtained when the concentration is 0.25 g/L. The maximum pressure (P max) and maximum pressure rise rate ((dP/dt) max) decrease by 52.41 % and 83.50 % respectively. The induction time and the time to maximum pressure are prolonged to 193 and 400 ms, respectively. The synergistic inhibition mechanism of physics and chemistry is illustrated in the analysis of post-explosion residues. This work provides an efficient and promising approach for the suppression of CH 4 /H 2 /air explosion by synthesizing the prolonged action inhibitor with a lotus leaf-like structure. [ABSTRACT FROM AUTHOR]