The influence of manganese-cobalt oxide/graphene on reducing fire hazards of poly(butylene terephthalate)

Design of a metal-organic framework with flame-retardant performance and bionic hydrophobic surface inspired by lotus leaf

This research proposes a simple and feasible method to prepare hydrophobic structures and it is a fortuitous finding. In our previous publication, triethyl phosphate is adsorbed on porous metal-organic framework...

Preparation and study of the flame retardant properties of C60/PMMA microspheres

In this paper, highly flame retardant C₆₀/PMMA composites were prepared using an in situ polymerization method by introducing fullerene (C₆₀) into polymethyl methacrylate (PMMA) to improve its combustion characteristics. The apparent morphologies of PMMA and C₆₀/PMMA microspheres were observed by scanning electron microscopy (SEM), and the structure was characterized by infrared spectroscopy (FT-IR). The thermal stability and flame retardancy were characterized using a synchronous thermal analyzer, a cone calorimeter and an oxygen index tester. The results show that the maximum initial decomposition temperature of C₆₀/PMMA-2 (prepared using C₆₀ with a concentration of 2 mg mL⁻¹) is 234.89 °C, which is about 59.89 °C higher than that of PMMA, and the thermal stability is the best. The limiting oxygen index of the C₆₀/PMMA-2 composite is 21.8, which is 28.2% higher than that of pure PMMA. In addition, the peak heat release rate (PHRR) of C₆₀/PMMA is reduced by 630.4 kW m⁻² when compared with pure PMMA, which means that the flame retardant property is improved. Meanwhile, the mechanical properties of the PMMA are also improved by adding C₆₀.

In this paper, highly flame retardant C₆₀/PMMA composites were prepared using an in situ polymerization method by introducing fullerene (C₆₀) into polymethyl methacrylate (PMMA) to improve its combustion characteristics.

Machine Learning and Structural Design to Optimize the Flame Retardancy of Polymer Nanocomposites with Graphene Oxide Hydrogen Bonded Zinc Hydroxystannate

Designing flame-retardant polymers with high performance is a long-standing challenge, partly because of the time-consuming traditional approaches based on experiential intuition and trial-and-error screenings. Inspired by the effective new paradigm of data-driven material discovery, we used machine learning to analyze experimental data to accelerate the development of new flame-retardant polymers. To explore the relationship between limit oxygen index (LOI) and components, we prepared 20 composites and then trained a simple equation for the LOI using the method sure independence screening and sparsifying operator (SISSO). The data analysis allows us for a better understanding of the flame-retardant mechanism and components, and the equation has good accuracy in guiding the design of composites with high flame-retardant performance. Meanwhile, the increasing structural design of flame retardants is crucial to flame-retardant polymer composites. We proposed a structure of nano graphene oxide (GO) wrapped micro zinc hydroxystannate (ZHS) in a simple but effective way as a novel flame-retardant agent to enhance the flame retardancy and mechanical properties of polypropylene (PP) composites. The GO sheets were like "light yarns" wrapped onto the ZHS via hydrogen bonding in an ethanol solution. The selected samples were analyzed to confirm the predictive LOI model. The resultant composites with the substitution of intumescent flame retardant (IFR) by 1.0, 2.0, and 4.0 wt % ZHS@GO conferred better flame retardancy compared with PP composite containing only IFR, reflected by the efficient increase of LOI value and V0 rating of UL-94 vertical tests. The analysis principles and facile fabrication strategies proposed in this work could be important for developing highly flame retardant composites.

Peanut Shell Derived Carbon Combined with Nano Cobalt: An Effective Flame Retardant for Epoxy Resin

Biomass-derived carbon has been recognised as a green, economic and promising flame retardant (FR) for polymer matrix. In this paper, it is considered that the two-dimensional (2D) structure of carbonised peanut shells (PS) can lead to a physical barrier effect on polymers. The carbonised sample was prepared by the three facile methods, and firstly adopted as flame retardants for epoxy resin. The results of thermal gravimetric analysis (TGA) and cone calorimeter tests indicate that the carbon combined with nano Cobalt provides the most outstanding thermal stability in the current study. With 3 wt.% addition of the FR, both peak heat release rate (pHRR) and peak smoke production rate (PSPR) decrease by 37.9% and 33.3%, correspondingly. The flame retardancy mechanisms of the FR are further explored by XPS and TG-FTIR. The effectiveness of carbonised PS can be mainly attributed to the physical barrier effect derived by PS's 2D structure and the catalysis effect from Cobalt, which contribute to form a dense char layer.

Synthesis of Transition Metal Complexes and Their Effects on Combustion Properties of Semi-Rigid Polyvinyl Chloride

Using introduction of MoO₄²⁻ and Fe³⁺, Cu²⁺, or Zn²⁺ into amphiphilic polymers (DN) via an ion-exchange reaction, different transition metal complexes, as retardants and smoke suppressants, including (DN)Mo, Fe(DN)Mo, Cu(DN)Mo, and Zn(DN)Mo were synthesized. Combined with the results of X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), it could be determined that ionic bonding of these ions with DN occurred. Subsequently, the influence of flame-retardant, smoke-suppression, and mechanical properties of (DN)Mo, Fe(DN)Mo, Cu(DN)Mo, and Zn(DN)Mo on polyvinyl Chloride (PVC) were tested. It was demonstrated that transition metal complexes of three metal elements, Fe(DN)Mo, Cu(DN)Mo, and Zn(DN)Mo, showed better flame retardancy, smoke suppression, and thermal stability as confirmed by microcalorimetry, limiting oxygen index (LOI), smoke density, and thermogravimetric analysis (TGA) tests, in which Cu(DN)Mo worked best due to the Lewis acid mechanism and reductive coupling mechanism. Scanning electron microscopy (SEM) showed that the addition of (DN)Mo, Fe(DN)Mo, Cu(DN)Mo, and Zn(DN)Mo promoted the formation of a dense carbon layer on the PVC surface during combustion, which could protect the interior PVC. The addition of these transition metal complexes hardly impaired the mechanical properties of PVC.

Ultra-long cycle life and binder-free manganese-cobalt oxide supercapacitor electrodes through photonic nanostructuring

We report a novel photonic processing technique as a next-generation cost-effective technique to instantaneously synthesize nanostructured manganese-cobalt mixed oxide reduced graphitic oxide (Mn-Co-rGO) for supercapacitor electrodes in energy storage applications. The active material was prepared directly on highly conductive Pt-Si substrate, eliminating the need for a binder. Surface morphological analysis showed that the as-prepared electrodes have a highly porous and resilient nanostructure that facilitates the ion/electron movement during faradaic redox reactions and buffers the volume changes during charge-discharge processes, leading to the improved structural integrity of the electrode. The presence of distinct redox peaks, due to faradaic redox reactions, at all scan rates in the cyclic voltammetry (CV) curves and non-linear nature of the charge-discharge curves suggest the pseudocapacitive charge storage mechanism of the electrode. The electrochemical stability and the life cycle were examined by carrying out galvanostatic charge-discharge (GCD) measurements at 0.40 mA cm^-2 constant areal current density for 80 000 cycles, and the electrode showed 95% specific capacitance retention, exhibiting excellent electrochemical stability and an ultra-long cycle life. Such remarkable electrochemical performance could be attributed to the enhanced conductivity of the electrode, the synergistic effect of metal ions with rGO, and the highly porous morphology, which provides large specific surface area for electrode/electrolyte interaction and facilitates the ion transfer.

Hydrothermal Synthesis of Lanthanum-Doped MgAl-Layered Double Hydroxide/Graphene Oxide Hybrid and Its Application as Flame Retardant for Thermoplastic Polyurethane

A novel lanthanum-doped MgAl-layered double hydroxide/graphene oxide hybrid (La LDH/GO) with a La3+/Al3+ molar ratio of 0.05 was successfully synthesized by the hydrothermal method. The structure and morphology of as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). Then, La LDH/GO was added into thermoplastic polyurethane (TPU) to investigate its effect on flame retardancy, smoke suppression, and thermal stability of TPU composites. The cone calorimeter test (CCT) results indicated that the peak heat release rate (PHRR) and peak smoke production rate (PSPR) values of TPU with La LDH/GO decreased by 33.1% and 51% compared with neat TPU, respectively. Therefore, La LDH/GO can play a good role in flame retardancy and smoke suppression of TPU matrix during combustion. In the meantime, La LDH/GO could improve the char yield of TPU composites, which is attributed to the interaction between the physical barrier effect of GO and the catalytic effect of 0.05 La LDH.

The influence of highly dispersed Cu2O-anchored MoS2 hybrids on reducing smoke toxicity and fire hazards for rigid polyurethane foam

The extensive utilization of rigid polyurethane foam (RPUF) as construction insulation material has brought two main troubles to our society: fire risks and toxic hazards. To reduce the fire hazards of RPUF, a layered MoS₂ decorated with Cu₂O nanoparticles was creativity obtained by hydrothermal technology and facile wet chemical treatment for reducing the toxic product formations of polyurethane nanocomposites during combustion. Due to the low weight ratio of Cu₂O attached onto MoS₂, the resulting Cu₂O-MoS₂ hybrid effectively prevented the MoS₂ nanosheets from restacking. However, the Cu₂O-MoS₂-M hybrid was produced by increasing content of Cu₂O, which has the characteristic stacked layer structure of MoS₂. Reduced harmful organic volatiles and the toxic gases (e.g. a respective decrease of ca. 28% and 53% for CO and NO_x products) were obtained because of synergistic effect between the physical adsorption of MoS₂ and catalysis action of Cu₂O. Notably, the addition of Cu₂O-MoS₂ hybrids led to high char formation of the RPUF nanocomposite, indicating the effectively catalytic carbonization property. In addition, the N-Gas model for predicting fire smoke toxicity was developed and demonstrated. Furthermore, the research offers direct proofs of the negative influence of the stacked MoS₂ on reducing the smoke toxicity for RPUF nanocomposites.

Interface decoration of exfoliated MXene ultra-thin nanosheets for fire and smoke suppressions of thermoplastic polyurethane elastomer

Thermoplastic polyurethane (TPU) has broad applications as lightweight materials due to its multiple advantages and unique properties. Nevertheless, toxicity emission under fire conditions remains a major concern, particularly in building fire scenarios. To circumvent the problem, it is imperative that an effective flame retardant is sought to suppress the flame and release of combustion/smoke products whilst maintaining the favorable material properties of TPU. In the current work, a simple method is proposed for the preparation and utilization of cetyltrimethyl ammonium bromide (CTAB) and tetrabutyl phosphine chloride (TBPC) modified Ti₃C₂ (MXene) ultra-thin nanosheets. During the cone calorimeter tests, significant reduction in peak heat release rate (51.2% and 52.2%), peak smoke production rate (57.1% and 57.4%), peak CO production (39.4% and 41.6%) and peak CO₂ production (49.7% and 51.7%) were recorded by the mere introduction of 2 wt.% CTAB-Ti₃C₂ and TBPC-Ti₃C₂ to TPU. These superior fire safety properties resulting from the significant reduction of the fire, smoke and toxicity hazards are attributed to the excellent dispersion, catalytic and barrier effect of Ti₃C₂ ultra-thin nanosheets in TPU. Future applications of exfoliated MXene nanosheets as flame retardant appear to be very promising.

Functionalization of MXene Nanosheets for Polystyrene towards High Thermal Stability and Flame Retardant Properties

Fabricating high-performance MXene-based polymer nanocomposites is a huge challenge because of the poor dispersion and interfacial interaction of MXene nanosheets in the polymer matrix. To address the issue, MXene nanosheets were successfully exfoliated and subsequently modified by long-chain cationic agents with different chain lengths, i.e., decyltrimethylammonium bromide (DTAB), octadecyltrimethylammonium bromide (OTAB), and dihexadecyldimethylammonium bromide (DDAB). With the long-chain groups on their surface, modified Ti3C2 (MXene) nanosheets were well dispersed in N,N-dimethylformamide (DMF), resulting in the formation of uniform dispersion and strong interfacial adhesion within a polystyrene (PS) matrix. The thermal stability properties of cationic modified Ti3C2/PS nanocomposites were improved considerably with the temperatures at 5% weight loss increasing by 20 °C for DTAB-Ti3C2/PS, 25 °C for OTAB-Ti3C2/PS and 23 °C for DDAB-Ti3C2/PS, respectively. The modified MXene nanosheets also enhanced the flame-retardant properties of PS. Compared to neat PS, the peak heat release rate (PHRR) was reduced by approximately 26.4%, 21.5% and 20.8% for PS/OTAB-Ti3C2, PS/DDAB-Ti3C2 and PS/DTAB-Ti3C2, respectively. Significant reductions in CO and CO2 productions were also obtained in the cone calorimeter test and generally lower pyrolysis volatile products were recorded by PS/OTAB-Ti3C2 compared to pristine PS. These property enhancements of PS nanocomposites are attributed to the superior dispersion, catalytic and barrier effects of Ti3C2 nanosheets.

Synergetic Improvement in Thermal Conductivity and Flame Retardancy of Epoxy/Silver Nanowires Composites by Incorporating "Branch-Like" Flame-Retardant Functionalized Graphene

The significant fire hazards on the polymer-based thermal interface materials (TIM) used in electronic devices are but often neglected. Also, high filler loading with the incident deterioration of mechanical, thermal, and processing properties limits the further application of the traditional polymer-based TIMs. In this work, a ternary TIMs with epoxy resin (EP) matrix, silver nanowires (AgNWs), and a small amount of flame-retardant functionalized graphene (GP-DOPO) were proposed to address the above questions. Briefly, a facile "branch-like" strategy with a polymer as the backbone and flame-retardant molecule as the branch was first used to functionalize reduced graphene oxide (RGO) toward increasing the flame-retardant grafting ratio and RGO's compatibility in matrix, and the resulted GP-DOPO was then in situ introduced into the EP/AgNW composites. As expected, the incorporation of GP-DOPO (2 wt %) can increase the thermal conductivity to 1.413 W/(m K) at a very low AgNW loading (4 vol %), which is 545 and 56% increments compared to pure EP and EP/AgNW, respectively. The prominent improvement in thermal conductivity was put down to the synergetic effect of AgNW and GP-DOPO, i.e., the improving dispersion and bridging effect for AgNWs by adding GP-DOPO. Moreover, the high flame-retardant grafting amount and the excellent compatibility of GP-DOPO resulted in a strong catalytic charring effect on EP matrix, which further formed a robust protective char layer by combining the AgNW and graphene network. Therefore, the flame retardancy of EP/AgNW was significantly improved by introducing GP-DOPO, i.e., the peak heat release rate, total heat release and total smoke production reduced by 27.0, 32.4, and 30.9% reduction compared to EP/AgNW, respectively.

Study on the Synergetic Fire-Retardant Effect of Nano-Sb₂O₃ in PBT Matrix

Nano-Sb₂O₃ has excellent synergistic flame-retardant effects. It can effectively improve the comprehensive physical and mechanical properties of composites, reduce the use of flame retardants, save resources, and protect the environment. In this work, nanocomposites specimens were prepared by the melt-blending method. The thermal stability, mechanical properties, and flame retardancy of a nano-Sb₂O₃–brominated epoxy resin (BEO)–poly(butylene terephthalate) (PBT) composite were analyzed, using TGA and differential scanning calorimetry (DSC), coupled with EDX analysis, tensile testing, cone calorimeter tests, as well as scanning electron microscopy (SEM) and flammability tests (limiting oxygen index (LOI), UL94). SEM observations showed that the nano-Sb₂O₃ particles were homogeneously distributed within the PBT matrix, and the thermal stability of PBT was improved. Moreover, the degree of crystallinity and the tensile strength were improved, as a result of the superior dispersion and interfacial interactions between nano-Sb₂O₃ and PBT. At the same time, the limiting oxygen index and flame-retardant grade were increased as the nano-Sb₂O₃ content increased. The results from the cone calorimeter test showed that the peak heat release rate (PHRR), total heat release rate (THR), peak carbon dioxide production (PCO₂P), and peak carbon monoxide production (PCOP) of the nanocomposites were obviously reduced, compared to those of the neat PBT matrix. Meanwhile, the SEM–energy dispersive spectrometry (EDX) analysis of the residues indicated that a higher amount of C element was left, thus the charring layer of the nanocomposites was compact. This showed that nano-Sb₂O₃ could promote the degradation and charring of the PBT matrix, improving thermal stability and flame retardation.

Comparative Studies on Thermal, Mechanical, and Flame Retardant Properties of PBT Nanocomposites via Different Oxidation State Phosphorus-Containing Agents Modified Amino-CNTs

High-performance poly(1,4-butylene terephthalate) (PBT) nanocomposites have been developed via the consideration of phosphorus-containing agents and amino-carbon nanotube (A-CNT). One-pot functionalization method has been adopted to prepare functionalized CNTs via the reaction between A-CNT and different oxidation state phosphorus-containing agents, including chlorodiphenylphosphine (DPP-Cl), diphenylphosphinic chloride (DPP(O)-Cl), and diphenyl phosphoryl chloride (DPP(O₃)-Cl). These functionalized CNTs, DPP(Ox)-A-CNTs (x = 0, 1, 3), were, respectively, mixed with PBT to obtain the CNT-based polymer nanocomposites through a melt blending method. Scanning electron microscope observations demonstrated that DPP(Ox)-A-CNT nanoadditives were homogeneously distributed within PBT matrix compared to A-CNT. The incorporation of DPP(Ox)-A-CNT improved the thermal stability of PBT. Moreover, PBT/DPP(O₃)-A-CNT showed the highest crystallization temperature and tensile strength, due to the superior dispersion and interfacial interactions between DPP(O₃)-A-CNT and PBT. PBT/DPP(O)-A-CNT exhibited the best flame retardancy resulting from the excellent carbonization effect. The radicals generated from decomposed polymer were effectively trapped by DPP(O)-A-CNT, leading to the reduction of heat release rate, smoke production rate, carbon dioxide and carbon monoxide release during cone calorimeter tests.

Graphene and activated carbon-wrapped and Co3O4-intercalated 3D sandwich nanostructure hybrid for high-performance supercapacitance

The graphene/Co₃O₄/activated carbon (GCA) 1 : 9 capacitor shows the best electrochemical properties with Co₃O₄ particles that were homogeneously dispersed between the graphene/Co₃O₄ (GC) layers.

Synthesis of graphene-transition metal oxide hybrid nanoparticles and their application in various fields

Single layer graphite, known as graphene, is an important material because of its unique two-dimensional structure, high conductivity, excellent electron mobility and high surface area. To explore the more prospective properties of graphene, graphene hybrids have been synthesised, where graphene has been integrated with other important nanoparticles (NPs). These graphene-NP hybrid structures are particularly interesting because after hybridisation they not only display the individual properties of graphene and the NPs, but also they exhibit further synergistic properties. Reduced graphene oxide (rGO), a graphene-like material, can be easily prepared by reduction of graphene oxide (GO) and therefore offers the possibility to fabricate a large variety of graphene-transition metal oxide (TMO) NP hybrids. These hybrid materials are promising alternatives to reduce the drawbacks of using only TMO NPs in various applications, such as anode materials in lithium ion batteries (LIBs), sensors, photocatalysts, removal of organic pollutants, etc. Recent studies have shown that a single graphene sheet (GS) has extraordinary electronic transport properties. One possible route to connecting those properties for application in electronics would be to prepare graphene-wrapped TMO NPs. In this critical review, we discuss the development of graphene-TMO hybrids with the detailed account of their synthesis. In addition, attention is given to the wide range of applications. This review covers the details of graphene-TMO hybrid materials and ends with a summary where an outlook on future perspectives to improve the properties of the hybrid materials in view of applications are outlined.

Effects of α-ZrP on Crystallinity and Flame-Retardant Behaviors of PA6/MCA Composites

Novel flame-retardant Polyamide6/Melamine cyanurate-alpha-zirconium phosphate (PA6/MCA-α-ZrP) composites were prepared via the incorporation of the modified MCA (MCA-α-ZrP) into PA6. MCA-α-ZrP were synthesized through the self-assembly of α-ZrP, Melamine (ME), and cyanuric acid (CA) molecules. The results of differential scanning calorimetry (DSC) and X-ray diffraction (XRD) showed that the incorporation of enough α-ZrP (30 wt% MCA) caused the increased crystallinity of PA6 and tended to form γ phase. The thermogravimetric analysis (TGA) and heat distortion temperature (HDT) test illustrated that the α-ZrP could increase the residue and HDT values of PA6/MCA and showed a synergistic effect with MCA. The combination of MCA and α-ZrP caused the enhancement of vertical burning test (UL-94) rating. Cone calorimeter test (CCT) gave clear evidences that PA6/MCA-10α-ZrP composites with low heat release rate (HRR), low total heat release (THR), and high amounts of char residues after combustion compared with PA6/MCA and PA6/MCA-30α-ZrP. What is more, excellent mechanical properties were kept even though MCA and α-ZrP were dispersed not as good as expected.

Simultaneous enhancements in the mechanical, thermal stability, and flame retardant properties of poly(1,4-butylene terephthalate) nanocomposites with a novel phosphorus–nitrogen-containing polyhedral oligomeric silsesquioxane

A novel functionalized POSS greatly reinforced the mechanical, thermal stability, and flame retardant properties of PBT.

A novel triazine-rich polymer wrapped MMT: synthesis, characterization and its application in flame-retardant poly(butylene terephthalate)

A novel flame retardant (PTAC–MMT) was successfully prepared by wrapping montmorillonite (MMT) with poly(2,4,6-triallyloxy-1,3,5-triazine) (TAC) via in situ polymerization, and its structure and properties were systematically characterized.

Space-Confined Growth of Defect-Rich Molybdenum Disulfide Nanosheets Within Graphene: Application in The Removal of Smoke Particles and Toxic Volatiles

In this work, molybdenum disulfide/reduced graphene oxide (MoS₂/RGO) hybrids are synthesized by a spatially confined reaction to insert the growth of defect-rich MoS₂ nanosheets within graphene to enable incorporation into the polymer matrix for the application in the removal of smoke particles and toxic volatiles. The steady-state tube furnace result demonstrates that MoS₂/RGO hybrid could considerably reduce the yield of CO and smoke particles. The TG-IR coupling technique was utilized to identify species of toxic volatiles including aromatic compounds, CO, and hydrocarbons and to investigate the removal effect of MoS₂/RGO hybrids on reducing toxic volatiles. The removal of smoke particles and toxic volatiles was attributed to the adsorption capacity derived from edges sites of MoS₂ and the honeycomb lattice of graphene, as well as the inhibition of nanobarrier resulting from two-dimensional structure. The work will offer a strategy for fabricating graphene-based hybrids by the space-confined synthesis and exploiting the application of space-confined graphene-based hybrid.

In situ loading ultra-small Cu2O nanoparticles on 2D hierarchical TiO2-graphene oxide dual-nanosheets: Towards reducing fire hazards of unsaturated polyester resin

Fire hazards have seriously hindered the commercial application of unsaturated polyester resin (UPR), and polymer inorganic nanosheet nanocomposites hold great promise in improving their flame-retardant properties. Herein, the hierarchical structured Cu₂OTiO₂GO nanosheets were synthesized and characterized by XRD, Raman, TEM and XPS. Then Cu₂OTiO₂GO nanosheets were incorporated into UPR matrix to obtain flame-retardant UPR nanocomposite. Incorporation of 2wt% Cu₂OTiO₂GO nanosheets into UPR matrix resulted in an obvious reduction in PHRR and THR by 29.7 and 19.1%. TG-IR-MS results revealed that toxic pyrolysis gas such as benzene, CO and aromatic compounds greatly were decreased. In addition, RIIR spectra demonstrated the limited influence of Cu₂OTiO₂GO nanosheets on thermal degradation of UPR matrix, and SEM images of char residues showed that Cu₂OTiO₂GO nanosheets could improve their compactness. Based on the analysis of gaseous and condensed phase, a plausible flame-retardant mechanism was hypothesized to elaborate how Cu₂OTiO₂GO nanosheets work inside the flaming UPR nanocomposite. This innovative idea may be expanded to other polymer system and open a new door to develop polymeric nanocomposites with high performance.

The influence of zinc hydroxystannate on reducing toxic gases (CO, NO(x) and HCN) generation and fire hazards of thermoplastic polyurethane composites

A uniform zinc hydroxystannate (ZnHS) microcube was synthesized to reduce toxicity and fire hazards of thermoplastic polyurethane (TPU) composites using ammonium polyphosphate as a flame retardant agent. The structure, morphology and thermal properties of ZnHS were characterized by X-ray diffraction, transmission electron microscopy and thermogravimetric analysis, respectively. Smoke suppression properties and synergistic flame retardant effect of ZnHS on flame retardant TPU composites were intensively investigated by smoke density test, cone calorimeter test, and thermalgravimetric analysis. Thermogravimetric analysis/infrared spectrometry and tube furnace were employed to evaluate the toxic gases (CO, NOx and HCN) of TPU composites. The incorporation of ZnHS into TPU matrix effectively improved the fire safety and restrained the smoke density, which is attributed to that the char residue catalyzed by ZnHS enhanced barrier effect that reduced peak heat release rate, total heat release, smoke particles and organic volatiles during combustion. Furthermore, the ZnHS synergist demonstrated high efficiency in catalytic degradation of the toxic gases, which obviously decreased total volatiled product and toxic volatiles evolved, such as the CO, HCN and NOx, indicating suppressed toxicity of the TPU composites.

Fabrication of binary hybrid-filled layer-by-layer coatings on flexible polyurethane foams and studies on their flame-retardant and thermal properties

A binary hybrid-filled flame-retardant coating, consisting of graphene oxide (GO) and amino-terminated silica nanospheres (KH-550-SiO₂), was fabricated onto a flexible polyurethane (FPU) foam using the layer-by-layer assembly method.

The effect of carbon nanotubes/NiFe2O4 on the thermal stability, combustion behavior and mechanical properties of unsaturated polyester resin

The incorporation of MWCNT@NiFe₂O₄ into the UPR matrix exhibit significant improvements in flame retardancy and mechanical properties, compared to that of pure UPR.

Hyper-branched polymer grafting graphene oxide as an effective flame retardant and smoke suppressant for polystyrene

A well-defined functionalized graphene oxide (FGO) grafted by hyper-branched flame retardant based on N-aminoethyl piperazine and phosphonate derivative was synthesized to reduce flammability and toxicity of polystyrene (PS). The chemical structure, morphological and thermal properties were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric analysis, respectively. Micro combustion calorimeter and steady state tube furnace were employed to evaluate the heat and non-heat fire hazards of PS nanocomposites. The incorporation of FGO into PS matrix effectively improved the flame retardancy and restrained the toxicity of the volatiles escaped, which is attributed to that the homogeneous dispersion of FGO in the PS matrix enhanced barrier effect that reduced peak heat release rate, total heat release and toxic gas release during combustion. Furthermore, PS-FGO nanocompsites obviously decreased the amount of flammable and toxic volatiles evolved, such as the aromatic compounds, carbonyl compounds, carbon monoxide, indicating suppressed fire hazards of the PS composites.

Aluminum hypophosphite microencapsulated to improve its safety and application to flame retardant polyamide 6

Aluminum hypophosphite (AHP) is an effective phosphorus-containing flame retardant. But AHP also has fire risk that it will decompose and release phosphine which is spontaneously flammable in air and even can form explosive mixtures with air in extreme cases. In this paper, AHP has been microencapsulated by melamine cyanurate (MCA) to prepare microencapsulated aluminum hypophosphite (MCAHP) with the aim of enhancing the fire safety in the procedure of production, storage and use. Meanwhile, MCA was a nitrogen-containing flame retardant that can work with AHP via the nitrogen-phosphorus synergistic effect to show improved flame-retardant property than other capsule materials. After microencapsulation, MCA presented as a protection layer inhibit the degradation of AHP and postpone the generation of phosphine. Furthermore, the phosphine concentration could be effectively diluted by inert decomposition products of MCA. These nonflammable decomposition products of MCA could separate phosphine from air delay the oxidizing reaction with oxygen and decrease the heat release rate, which imply that the fire safety of AHP has been improved. Furthermore, MCAHP was added into polyamide 6 to prepare flame retardant polyamide 6 composites (FR-PA6) which show good flame retardancy.

Graphene-based transition metal oxide nanocomposites for the oxygen reduction reaction

The development of low cost, durable and efficient nanocatalysts to substitute expensive and rare noble metals (e.g. Pt, Au and Pd) in overcoming the sluggish kinetic process of the oxygen reduction reaction (ORR) is essential to satisfy the demand for sustainable energy conversion and storage in the future. Graphene based transition metal oxide nanocomposites have extensively been proven to be a type of promising highly efficient and economic nanocatalyst for optimizing the ORR to solve the world-wide energy crisis. Synthesized nanocomposites exhibit synergetic advantages and avoid the respective disadvantages. In this feature article, we concentrate on the recent leading works of different categories of introduced transition metal oxides on graphene: from the commonly-used classes (FeOx, MnOx, and CoOx) to some rare and heat-studied issues (TiOx, NiCoOx and Co-MnOx). Moreover, the morphologies of the supported oxides on graphene with various dimensional nanostructures, such as one dimensional nanocrystals, two dimensional nanosheets/nanoplates and some special multidimensional frameworks are further reviewed. The strategies used to synthesize and characterize these well-designed nanocomposites and their superior properties for the ORR compared to the traditional catalysts are carefully summarized. This work aims to highlight the meaning of the multiphase establishment of graphene-based transition metal oxide nanocomposites and its structural-dependent ORR performance and mechanisms.