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Lithium‐ion batteries have found extensive applications due to their high energy density and low self‐discharge rates, spanning from compact consumer electronics to large‐scale energy storage facilities. Despite their widespread use, challenges such as inherent capacity degradation and the potential for thermal runaway hinder sustainable development. In this study, we introduce a unique approach to synthesize anode materials for lithium‐ion batteries, specifically imidazole‐intercalated cobalt hydroxide. This innovative material significantly enhances the Li+ desolvation/diffusion reaction and flame‐retardant dynamics through complexing and catalytic synergetic effects. The lithium‐ion batteries incorporating these materials demonstrate exceptional performance, boasting an impressive capacity retention of 997.91 mAh g−1 after 500 cycles. This achievement can be attributed to the optimization of the solid electrolyte interphase (SEI) interface engineering, effectively mitigating anode degradation and minimizing electrolyte consumption. Experimental and theoretical calculations validate these improvements. Importantly, imidazole intercalated Co(OH)2 (MI−Co(OH)2) exhibits a remarkable catalytic effect on electrolyte carbonization and the conversion of CO to CO2. This dual action suppresses smoke and reduces toxicity significantly. The presented work introduces a novel approach to realizing high‐performance and safe lithium‐ion batteries, addressing key challenges in the pursuit of sustainable energy solutions. [ABSTRACT FROM AUTHOR]

Graphite anode materials and carbonate electrolyte have been the top choices for commercial lithium-ion batteries (LIBS) for a long time. However, the uneven deposition and stripping of lithium cause irreversible damage to the graphite structure, and the low flash point and high flammability of the carbonate electrolyte pose a significant fire safety risk. Here, we proposed a multifunctional electrolyte additive diphenylphosphoryl azide (DPPA), which can construct a solid electrolyte interphase (SEI) with high ionic conductivity lithium nitride (Li3N) to ensure efficient transport of Li+. This not only protects the artificial graphite (AG) electrode but also inhibits lithium dendrites to achieve excellent electrochemical performance. Meanwhile, the LIBS with DPPA offers satisfactory flame retardancy performance. The AG//Li half cells with DPPA-0.5M can still maintain a specific capacity of about 350 mAh/g after 200 cycles at 0.2 C. Its cycle performance and rate performance were better than commercial electrolyte (EC/DMC). After cycling, the microstructure surface of the AG electrode was complete and flat, and the surface of the lithium metal electrode had fewer lithium dendrites. Importantly, we found that the pouch cell with DPPA-0.5M had low peak heat release rate. When exposed to external conditions of continuous heating, DPPA significantly improved the fire safety of the LIBS. The research of DPPA in lithium electrolyte is a step towards the development of safe and efficient lithium batteries. [ABSTRACT FROM AUTHOR]

Unsaturated polyester resins (UPR) are broadly applied in chemical, construction, transportation and electrical fields, etc. However, UPR materials are extremely flammable. Through radiation, conduction and convection, the released heat brings serious thermal hazards to surrounding life and the environment. Meanwhile, the combustion of UPR also releases a vast of toxic pyrolysis gases and smoke, causing extremely serious non-thermal hazards, endangering life and health, reducing fire visibility and hindering escape and rescue efforts. Therefore, the flame retardant modification of UPR materials is an inevitable measure to reduce its flammability and broaden its application breadth. In this review, the flammability of UPR materials is firstly analyzed from the perspective of their compositions and structures. Meanwhile, based on the differences in preparation methods of flame retardant UPR (FR-UPR) in literature research, it is divided into additive flame retardant, intrinsic flame retardant and interfacial flame retardant methods. The relationship between the highly efficient flame retardant structures and the properties, and the gaseous-phase flame retardant and condensed-phase mechanisms in FR-UPR composites are analyzed. Compared with traditional additive flame retardants, polymeric flame retardants, nanosheet flame retardants and intrinsic flame retardant method are important directions for the future development of FR-UPR composites. In addition, the interfacial flame retardant method can effectively improve the interfacial adhesion and flame retardant properties of fiber-reinforced UPR composites, and also has application prospects. This review analyzes the current challenges faced by FR-UPR, and looks forward to its possible future development directions to guide the preparation and application of high-performance FR-UPR. [ABSTRACT FROM AUTHOR]

Herein, piperazine phosphoramide derivatives (PPDO) and titanium carbide modified by hexadecyl trimethyl ammonium bromide (c-Ti3C2) were blended with epoxy resin (EP) to fabricate EP/c-Ti3C2/PPDO nanocomposites. According to thermogravimetric analyzer (TGA) results and pyrolysis kinetic analysis, EP/c-Ti3C2/PPDO nanocomposites can improve the thermal stability and the activation energy of EP. Furthermore, thermal degradation mechanism of EP and its nanocomposites with conversion between 0.55 and 0.99 conforms to the F3 model. With 1 wt% c-Ti3C2 and 3 wt% PPDO incorporated, the LOI value of EP/c-Ti3C2-1/PPDO-3 can reach up to 32% while achieves V-0 rating in the UL-94 test. Based on the cone calorimeter results, the peak heat release rate of EP/c-Ti3C2-1/PPDO-3 reduced by 40.1%. More continuous and dense phosphorus-rich char residues were produced for EP/c-Ti3C2-1/PPDO-3 nanocomposites, which can act as a physical barrier to hinder the heat transfer, protect the underlying polymers from further decomposition and isolate the diffusion of combustible gases. The synergistic effect between c-Ti3C2 and PPDO in catalytic carbonization obviously accounts for the improved flame retardant performance. This work provides an insight into the flame retardant mechanism and the thermal degradation mechanism of c-Ti3C2 and PPDO on EP, showing a promising application potential of c-Ti3C2 and PPDO in enhancing the thermal stability and flame retardancy of EP. [ABSTRACT FROM AUTHOR]

The output of bio-based polyvinyl alcohol (PVA) has been growing rapidly with a substantial increase of developments both in academic and industrial research areas in the past decade, which is due to its water solubility, plasticity, and degradability. However, PVA is highly flammable with a limiting oxygen index of only 19% owning to its inherent macromolecular structure composed of carbon, hydrogen, and oxygen atoms. The demand for flame retardancy of PVA has been increased rapidly and is generally satisfied by introducing flame retardants via chemical grafting, physical blending, and coating. This review summarizes the flame retardants applied in PVA and their influence on the flammability and mechanical properties of PVA materials. The type of flame retardant additives and their application technologies for various PVA products are presented in terms of various PVA products, such as films, aerogel, fibers, foams, and bulk composites. The films dominate the whole research of flame retardant PVA materials owing to their widespread application. The fire performance and flame retardant mechanism are compared and discussed. Additionally, PVA acted as an assistant agent in some polymeric flame-retardant formulations is also discussed and reviewed. [ABSTRACT FROM AUTHOR]

In this work, apigenin was chosen as a raw material to synthesize a novel epoxy monomer (DGEA), while the bio-based epoxy resin was further obtained after curing with 4,4′-diaminodiphenylmethane (DDM). The control samples were prepared by curing diglycidyl ether of bisphenol A (DGEBA) with DDM. The non-isothermal differential scanning calorimeter (DSC) method was utilized to further investigate the curing behavior and curing kinetics of the DGEA/DDM system. Despite no flame retardant active elements, the DGEA/DDM thermoset still exhibited exceptional anti-flammability. Specifically, the DGEA/DDM thermoset reached a V-0 rating in the UL-94 test and owned a high limiting oxygen index (LOI) value of 37.0%, while DGEBA/DDM resins were consumed completely in the vertical combustion test with a low LOI of 23.0%. Furthermore, the microscale combustion calorimetry (MCC) results manifested that compared with DGEBA/DDM resins, both PHRR and THR values of the DGEA/DDM resins were dropped by 84.0% and 57.6%, respectively. Additionally, the DGEA/DDM resin also presented higher storage modulus and tensile strength compared with DGEBA/DDM one. Particularly, in contrast with that of the cured DGEBA/DDM one (156 °C), the DGEA/DDM thermoset displayed an extremely high glass transition temperature (232 °C). This study breaks new ground on how to produce bio-based monomers with aromatic structures and achieve high-performance thermosetting polymers. [ABSTRACT FROM AUTHOR]

Phosphorus–nitrogen–silicon-containing coatings consisting of tris(hydroxymethyl)phosphine oxide (THPO), 3,5-diamino-1,2,4-triazole (guanazole), and polydimethylsiloxane (PDMS) were prepared via a simple spraying deposition technique and applied to the cotton fabric to impart flame retardancy and hydrophobicity. SEM image reveals that THPO/Guanazole/PDMS-coated fabric has a rough surface and XPS spectra confirm the composition of the coating on the cotton surface. Direct flame testing indicates that the as-prepared coating can protect the cotton from burning. The limiting oxygen index increased from 18.0% for the uncoated fabric to 32.0% for the THPO/Guanazole-treated sample and 27.0% for the THPO/Guanazole/PDMS-treated sample. Furthermore, with additional THPO/Guanazole, there was a gradual reduction in PHRR values, 60% (79.0 kW/m2) for C2 and 76% (48.2 kW/m2) for C3 lower than that of untreated cotton. After hydrophobic treatment of C2 with PDMS, the PHRR is reduced to 127.5 kW/m2 (35.5% for C2-PDMS). Additionally, the coated cotton displays impressive hydrophobicity with a water contact angle of 133°. This unique approach provides a facile and effective flame retardant and hydrophobic treatment for cotton fabric. [ABSTRACT FROM AUTHOR]

A high content of flame retardant in non‐combustible electrolytes leads to deterioration of the electrochemical performance of lithium‐ion batteries (LIBs). Besides, fire hazard of most non‐flammable electrolytes is studied in coin cell, for which it is impossible to reveal real performance. Thus, the stable interfacial, phosphorus‐fixed nonflammable gel polymer electrolyte (GPE) with low content of flame retardant (7.5 wt.%) has been designed by in situ polymerization of tri(acryloyloxyethyl) phosphate and triethylene glycol dimethacrylate in electrolyte. After being heated by fire for >10 s, the GPE is still not ignited. The average capacity attenuation rate of graphite//GPE//Li (0.008%) is much lower than that of the liquid electrolyte (0.039%). Besides, the nonflammable GPE based pouch cell with good flexibility and excellent fire safety is prepared. No fire, no thermal runaway and no electrolyte leakage occur for 1 Ah flexible pouch cell with 100% SOC. The mechanism for high safety of pouch cell has also been revealed. First the amount of combustible pyrolysis products from thermal degradation of GPE is reduced through forming P and F containing char. Second, the combustion of GPE is extinguished through OH free radical quenching effect of flame retardant molecular. This work provides a guideline for designing high‐safety LIBs. [ABSTRACT FROM AUTHOR]

Wildfires have been recognized as a natural incident in some forests, however, fire season is now more severe and extensive, even in tropical rainforests in which fire could have damaging impacts. A hydrogel is a 3-D polymeric structure encompassing cross-linked and hydrophilic macromolecules. In comparison with water, hydrogels have shown some superiorities in terms of water-binding, cooling, and sealing, which make them be applied in forest fire prevention programs for improving fire-extinguishing performance. In this study, an environmentally friendly phosphorus-modified methylcellulose/silica hybrid hydrogel was prepared based on the modified methylcellulose by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide–itaconic acid (DOPO-ITA) and silica nanoparticles. In the fire prevention experiments, the grass treated with the methylcellulose@DOPO-ITA@silica hybrid hydrogel shows self-extinguishing behavior, whereas those treated with ordinary water or methylcellulose hydrogel can be easily ignited after one week. In the firefighting experiments, the methylcellulose@DOPO-ITA@silica hybrid hydrogel displays a much shorter extinguishing time and lower consumption volume than ordinary water and the methylcellulose@DOPO-ITA hydrogel. This work presents an environmentally friendly, non-toxic, and biodegradable cellulose-based hybrid hydrogel for the fire prevention and firefighting of wildfires. [ABSTRACT FROM AUTHOR]

Rice, as one of the most valuable bio-resources, is combustible in nature, which poses an inevitable fire risk for the storage and transport processes. The propensity of rice mold could change the fire hazard and endangers the food security of human beings. In this work, the smoldering spread of normal rice, mildly and severely molded rice were studied under the forced opposed airflow. As the rice molding degree increased, the particle pore surface area increased to enhance the char oxidation. Consequently, the smoldering temperature was higher, the propagation rate became larger, and smoldering was more likely to transition to flame, showing a significant fire hazard and explosion risk. Results also showed that as the moisture content increased, both the smoldering temperature and the propensity to flaming increased, probably because of the increased airflow speed after the expansion of rice particles. This research proves that the molding degree has a significant impact on the fire risk and hazard of rice storage and drying process, thus helping provide a scientific guideline for the safe storage and transportation of rice. [ABSTRACT FROM AUTHOR]

In order to reduce greenhouse gas emissions, developing flame retardants from bio-based resources has aroused extensive interest in recent years. In this work, we utilized furfural (biomass) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to synthesize a bio-based co-curing agent (FGD) to combine with 4,4'-diaminodiphenyl methane (DDM) for obtaining a low-phosphorus loading flame-retardant epoxy thermosets. The introduction of FGD decreased the activation energy of the curing progress, enhanced the mechanical properties of the epoxy thermosets, and did not affect the glass transition temperature of the epoxy thermosets. EP-5.0 had a lower thermal degradation rate and a doubled char yield compared with EP-0. The phosphorus content of EP-5.0 was only 0.45 wt%, while EP-5.0 reached the UL-94 V-0 rating with a high LOI value of 32%. Compared with EP-0, the PHRR of EP-2.5 and EP-5.0 decreased by 22.3% and 31.3%, respectively. The SEM results showed that the addition of FGD made the char residues more uniform and denser, which could effectively prevent combustible volatiles from escaping from the degradation area to the flame area and isolate the heat transfer so that the epoxy thermosets had an excellent flame-retardant performance. [ABSTRACT FROM AUTHOR]

A systematic series of flexible polyurethane foams (FPUF) with different concentrations of flame retardants, bis([dimethoxyphosphoryl]methyl) phenyl phosphate (BDMPP), and melamine (MA) or expandable graphite (EG) was prepared. The mechanical properties of the FPUFs were evaluated by a universal testing machine. The pyrolysis behaviors and the evolved gas analysis were done by thermogravimetric analysis (TGA) and TGA coupled with Fourier‐transform infrared (TG‐FTIR), respectively. The fire behaviors were studied by limiting oxygen index (LOI), UL 94 test for horizontal burning of cellular materials (UL 94 HBF), and cone calorimeter measurement. Scanning electronic microscopy (SEM) was used to examine the cellular structure's morphology and the postfire char residue of the FPUFs. LOI and UL 94 HBF tests of all the flame retarded samples show improved flame retardancy. BDMPP plays an essential role in the gas phase because it significantly reduces the effective heat of combustion (EHC). This study highlights the synergistic effect caused by the combination of BDMPP and EG. The measured char yield from TGA is greater than the sum of individual effects. No dripping phenomenon occurs during burning for FPUF‐BDMPP‐EGs, as demonstrated by the result of the UL 94 HBF test. EG performs excellently on smoke suppression during burning, as evident in the result of the cone calorimeter test. MA reduces the peak heat release rate (pHRR) significantly. The synergistic effect of the combination of BDMPP and EG as well as MA offers an approach to enhance flame retardancy and smoke suppression. [ABSTRACT FROM AUTHOR]

As one of the most used polyurethane, flexible polyurethane foam (FPUF) still confronted highly flammable problems. However, current flame retardant employed in FPUF deteriorated the other utilization performances, such as mechanical properties. In this work, cerium stannate decorated graphene nanosheets (GNS@Ce2Sn2O7, GCSO) was prepared to fabricate flame retardant FPUF composites. Compared to pure FPUF, the tensile strength and average compression strength of FPUF composites accomplished 100 and 412% increase, respectively, while the average rebound was basically maintained. In contrast to pure FPUF, total heat release and total smoke production of FPUF composites displayed a 42.2 and 75.1% reduction, respectively. Furthermore, the released toxic gases (such as, CO2, CO and NOx) during combustion were greatly decreased. These results were due to the catalytic and barrier effect of GCSO promoting the formation a high‐quality char residue with a compact, intact and dense morphology. Therefore, it provides a facile method to fabricate FPUF composites with advanced comprehensive performance for the furniture field. [ABSTRACT FROM AUTHOR]

Cellulose as a bio-based material has attracted increasing attention due to its excellent properties. However, cellulose is very flammable and it is necessary to impart flame retardancy to cellulose nanofiber (CNF) foams. In this work, phytic acid (PA)-guanazole (GZ)-CNF composite foams were prepared by a simple freeze-drying method. SEM images indicated that the resultant PA-GZ-CNF composite foams exhibited a hierarchical porous structure. Moreover, the introduction of PA and GZ slightly affected the thermal conducting property of CNF foams. PA-GZ-CNF composite foams possessed excellent flame retardancy with a much higher LOI value and a UL-94 V-0 rating compared to that of pure CNF foams. Moreover, the peak of the heat release rate of PA-GZ-CNF composite foams exhibited a significant decrease from 57.80 to 29.27 kW/m2 and the total heat release declined from 2.10 to 1.21 MJ/m2. PA-GZ-CNF composite foams formed a protective char layer covered on the surface, which produced less thermal decomposition volatiles and prevented the spread of pyrolysis products into the gas phase. Additionally, PA-GZ-CNF composite foams achieved hydrophobicity with a water contact angle of 104.0° after hydrophobic treatment without sacrificing their flame retardancy. [ABSTRACT FROM AUTHOR]

The high fire safety of polymer nanocomposites is being pursued by research institutions around the world. In addition to intrinsic flame retardancy strategy, the additive-type flame retardants have attracted increasing attention due to low commercial cost and easy fabrication craft. However, traditional additive-type flame retardants usually need high addition amount to achieve a desirable effect, which causes many side-effects on the overall performance of polymer materials, such as deteriorated mechanical property and processability. At present, two-dimensional (2D) nanomaterials have also been applied to reduce the fire hazards of polymer (nano)composites with the coupling of barrier function and catalysis as well as carbonization effect. Even though most research work mainly focus on graphene-based flame retardants, more emerging two-dimensional nanomaterials are taking away research attention, due to their complementary and unique properties, mainly including hexagonal boron nitride (h-BN), molybdenum disulfide (MoS2), metal organic frameworks (MOF), carbon nitride (CN), titanium carbide (MXene) and black phosphorene (BP). In this review, except for graphene, the flame retardant mechanism involving different layered nanomaterials are also reviewed. Meanwhile, the functionalization method and flame retardancy effect of different layered nanomaterials are emphatically discussed for offering an effective reference to solve the fire hazards of polymer materials. Moreover, this work objectively evaluates the practical significance of polymer/layered nanomaterials composites for industrial application. [ABSTRACT FROM AUTHOR]

• Multi-elemental based flame retardant treatment was done for PA66 textiles • The flame retardancy and thermal stability were escalated in a several fold • P, N and Si elements based coating improved the LOI value by 25.5 % • A reduction by 34 % in pHRR was achieved from P, N, Si and B elements • A minimal add on % can surely impart total fire retardancy to PA66 textiles Multi-elements based hybrid (i.e., organic/inorganic) flame retardant compounds, namely phenyl dichlorophosphate (PDP) based two different engineered structures synthesized with (3-Aminopropyl) triethoxysilane (APTES) (i.e., containing P, N and Si) and boric acid-doped-APTES (BA-d-APTES) (i.e., containing P, N, Si and B) were considered in escalating the fire performance of polyamide 66 (PA66) textiles. All the treated fabrics irrespective of type and loading % (i.e., 5–10 wt. %) of flame retardant compounds exhibited better thermal stability at a higher temperature range and produced enhanced charring. In line, such treatment increased the limiting oxygen index (LOI) value by up to 25.5 % for the fabric sample modified with 10 wt. % of PDP-APTES (i.e., PA66-PDP-A-10W). Moreover, the applied finishing diminished the serious dripping of PA66 textiles completely and brought a significant reduction in the peak heat release rate (pHRR) by 34 % along with a slight reduction in the total heat release rate (THR) by about 5 %. Even more, such treatment left a negligible impact of mechanical properties of treated textiles while offered a considerable durability against home laundering. Thus, these multi-elemental based hybrid compounds optimized in the condensed phase mechanism were found to be an effective flame retardant for PA66 textiles. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• TiO 2 /SiO 2 NPs based multifunctional coatings were prepared for PA66 textiles • The flame retardancy and hydrophilicity were escalated in a several fold • The TiO 2 nanoparticle along with phytic acid improved the LOI value by 24.5% • TiO 2, phytic acid and chitosan handed a substantial reduction in pHRR by 25% • SiO 2 nanoparticle and phytic acid formulation enhanced hydrophilicity markedly Novel nanoparticles (NPs) namely, TiO 2 and SiO 2 along with naturally derived phytic acid (PA) and chitosan (CS) were used to improve the flame retardant and hydrophilic properties of polyamide 66 (PA66) fabrics via pad-dry-cure technique. The application of PA-TiO 2 enhanced the limiting oxygen index (LOI) value up to 24.5 % for the treated fabrics from 19.5% of the pure fabric and accelerated char yield%. Conversely, the introduction of chitosan (CS) into the PA-TiO 2 /SiO 2 formulations brought a significant reduction in the peak heat release rate (pHRR) where a maximum reduction of 25 % was achieved for the PA66-PA-CS-T fabric sample. Meanwhile, the hydrophilicity of treated fabrics was improved significantly, especially with PA-SiO 2 formulation as the water contact angle was reduced to 29˚ for the treated fabrics from 112˚ for the pure PA66. In addition, the formulations containing nanoparticles (TiO 2 /SiO 2) along with PA boosted up the tensile strength of treated textiles. [ABSTRACT FROM AUTHOR]

Fabrics with high flame-retardancy have been extensively applied for numerous applications including textile, garments, automobile industries, pants, shirts, suits bed sheets, and indoor decorations. Coatings consisting of ammonium hexametaphosphate (NH4-HMP), laponite (LAP), and hexadecyltrimethoxysilane were synthesized through sol–gel method; they were then employed on the cotton fabrics to enhance their hydrophobicity and flame retardancy. The influences of LAP concentration on fire-retardancy of the samples were evaluated. The combustion behavior, morphological structures, thermal stability, and hydrophobic properties of the cotton fabrics were studied. Results indicated the excellent flame retardant property of the treated cotton fabrics as they immediately extinguished upon removal of the flame source. The limiting oxygen index of the treated cotton was enhanced to 29% in comparison to that of the pure one (19.5%). The findings also indicated that a higher concentration of LAP is useful for improving flame retardancy of the coated substrate. In addition, the hydrophobicity of the fabric surface was measured by a water contact angle of 138°, while its superoleophilicity was assessed by an oil contact angle of 0°. To separate water–oil mixtures, the as-prepared cotton sample was utilized as operative substances. Overall, in this study a facile technique is provided for preparing cotton fabrics with considerably enhanced flame retardancy and superior self-cleaning features toward different fluids making them suitable as a promising candidate for water–oil separation. [ABSTRACT FROM AUTHOR]

In the current study, Zeolitic Imidazole Framework-8 (ZIF-8) was in situ grown on the surface of cellulose fibers and the ZIF-8@cellulose composite aerogels were fabricated by a freeze-drying method. The flame-retardant, thermal and mechanical characteristics of the cellulose-based aerogels were investigated. SEM images indicated that ZIF-8 was evenly deposited on the surface of the cellulose fibers in the aerogel owing to formation of hydrogen bonding with cellulose molecules. The addition of ZIF-8 enhanced thermal stability and flame retardancy of the host cellulose aerogel. The peak of heat release rate of the ZIF-8@cellulose-3 composite aerogel exhibited a drastic decline from 128 W g−1 to 63 W g−1 and the total heat release from 25.9 kJ g−1 to 14.8 kJ g−1. In the UL-94 vertical burning test, the samples showed self-extinguishing behavior. Additionally, ZIF-8 induced a dramatic enhancement in the mechanical properties of the host cellulose. Specifically, the compressive stress of the ZIF-8@cellulose composite aerogel showed a significant increase from 0.45 to 34.80 MPa. Moreover, the ZIF-8@cellulose composite aerogel can selectively remove the organic pollutants from water and adsorb a wide range of liquid oils with considerable capacities. The current study presented a feasible approach to synthesis of strong and flame-retardant cellulose-based aerogels for waste water purification. [ABSTRACT FROM AUTHOR]

Inhalation exposure to flame retardants used as additives to minimize fire risk and plasticizers is ubiquitous in human daily activities, but has not been adequately assessed. To address this research gap, the present study conducted an assessment of human health risk for four age groups through inhalation exposure to size fractionated particle-bound and gaseous halogenated flame retardants (polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs)) and organophosphate esters (OPEs) at indoor and outdoor environments (school, office, and residence) in three districts of a megacity (Guangzhou, China). Results demonstrated that OPEs were the dominant components among all targets. Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels for all age groups. Gaseous OPEs contributed significantly greater than particle-bound compounds to daily intakes of all target compounds. Based on the different life scenarios, hazard quotient (HQ) and incremental life cancer risk (ILCR) from adults exposure to PBDEs and OPEs in indoor and outdoor settings were the greatest, followed by adolescents, children, and seniors. The estimated HQ and ILCR for all age groups both indoors and outdoors were lower than the safe level (HQ = 1 and ILCR = 10−6), indicating that the potential health risk for local residents in Guangzhou via inhalation exposure to atmospheric halogenated flame retardants and OPEs was low. Image 1 • Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels. • Daily intakes of gaseous OPEs were greater than particle-bound OPEs. • Inhalation exposure health risk for residents in Guangzhou to PBDEs and OPEs was low. Comprehensive investigation of indoor and outdoor polybrominated diphenyl ethers and organophosphate esters are conducted to provide new insight in risk assessment of human inhalation exposure to atmospheric halogenated flame retardants and plasticizers in an urban zone. [ABSTRACT FROM AUTHOR]

Graphene‐polyaniline/nickel hydroxide ternary hybrid (RGO‐PANI/Ni(OH)2) was synthesized and incorporated into epoxy resin (EP) to improve the fire retardant property. Thermogravimetric analysis results showed that the RGO‐PANI/Ni(OH)2 nanohybrid could catalyze the thermal degradation of epoxy matrix that was essential to trigger the char formation. The char yield of the RGO‐PANI/Ni(OH)2/EP composite was improved compared with that of the samples with graphene and polyaniline only. With 3.0‐wt% RGO‐PANI/Ni(OH)2, significant reduction in peak heat release rate (40%) and peak smoke production rate (36%) was observed in the cone calorimeter tests. Thermogravimetric analysis/infrared spectrometry (TG‐IR) results indicated that the flammable volatiles of the RGO‐PANI/Ni(OH)2/EP composite was reduced compared with those of the EP and RGO‐PANI/EP. The superior flame retardant and smoke suppressant behaviors of the RGO‐PANI/Ni(OH)2 nanohybrid over RGO‐PANI were attributed to the combination of good barrier effect of graphene with catalytic ability of char formation of PANI and metal hydroxide. [ABSTRACT FROM AUTHOR]

A novel and highly effective flame retardant (FR), DOPO‐TPMP oligomer, was synthesized by a simple condensation of 4‐(hydroxymethyl)‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane‐1‐oxide and phosphorus oxychloride followed by a polycondensation reaction with 6‐(2,5‐dihydroxyphenyl)‐6H‐dibenzo[c,e][1,2]oxaphosphinine‐6‐oxide. The chemical structure of DOPO‐TPMP was well characterized using Fourier transform infrared and NMR spectra. DOPO‐TPMP was used as an additive‐type FR for epoxy resin (EP). The FR properties of the resultant EP composites were investigated by limiting oxygen index (LOI) test, UL‐94 vertical burning test and cone calorimeter measurements. Specifically, the EP composite containing 10.0% DOPO‐TPMP achieved a LOI value of 36.1%, V‐0 rating in the UL‐94 test and a 58% reduction in peak heat release rate. Further mechanism analysis attributed the enhanced flame retardancy to the increased char yield on the addition of DOPO‐TPMP. © 2019 Society of Chemical Industry A novel oligomeric flame retardant, DOPO‐TPMP, was synthesized, which imparted high flame‐retardant performance to epoxy resins. [ABSTRACT FROM AUTHOR]

In this work, two kinds of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based phosphonamidate flame retardants named 4,4′-diamino-diphenyl methane (DDM)-DOPO and morpholine (MPL)-DOPO are successfully synthesized by the classic Atherton–Todd reaction, and their chemical structures are characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Epoxy composites containing DDM-DOPO or MPL-DOPO are prepared, which still retain relatively high transparency compared with pure epoxy resin (EP). Its fire behavior is studied in terms of vertical burning test (UL-94), limiting oxygen index (LOI), and cone calorimeter tests. The LOI values can achieve 30% and UL-94 test past V-0 rating for DDM-DOPO-modified epoxy composites with 0.25 wt% phosphorus content. The cone calorimeter results indicate that the modified epoxy composites can release less heat and smoke compared with pure EP. Also, thermal degradation behavior and flame-retardant mechanism of epoxy composites are investigated by thermogravimetric analysis and thermogravimetric analysis/infrared spectrometry. The results indicate that two DOPO-based phosphonamidates show a significant gaseous-phase effect on reducing the release of combustible volatiles. [ABSTRACT FROM AUTHOR]

Building energy consumption is an important component in the total social energy consumption. How to reduce building energy consumption became an important issue in today's society. Therefore, building insulation materials, as a kind of effective energy saving method, has been widely used for the external walls. However, the occurrence of many building fires caused by the ignition of the flammable insulation materials has brought serious damage to people. Consequently, it is significant to develop insulation materials which possess high level of fire safety. The aim of this study was to develop high efficient phosphorus‐based flame‐retardant system for polyisocyanurate‐polyurethane (PIR‐PUR) foam. Ammonium polyphosphate (APP) was used as condensed phase flame retardant and dimethyl methylphosphonate (DMMP) were used as gas phase flame retardant for preparing flame‐retardant PIR‐PUR foam. The flame retardancy, thermal decomposition, and combustion behaviors of PIR‐PUR foams were evaluated by limiting oxygen index (LOI) test, vertical burning test, thermogravimetric analysis, cone calorimeter test (Cone), and microscale combustion calorimeter test, respectively. The LOI results showed that the PIR‐PUR sample simultaneously containing APP and DMMP possessed higher flame retardant efficiency, which indicated that APP and DMMP possessed synergistic flame‐retardant effect in PIR‐PUR foam. Cone results indicated that the presence of DMMP can delay the ignition of specimen and delay the time to reach the maximal peak heat release rate. Moreover, the mechanical performance and thermal insulating properties were evaluated, respectively. [ABSTRACT FROM AUTHOR]

The exploration of green flame retardants is of great significance for fire safety, ecological environment protection, and resource saving. Herein, a novel phosphorus containing chitosan‐cobalt complex (CS‐P‐Co) was successfully synthesized for the first time and then introduced into polylactic acid matrix. Owning to the formation of cobalt salts, the CS‐P‐Co exhibits good thermal stability and catalytic char effect. The as‐fabricated biodegradable polylactic acid/CS‐P‐Co composites with small amounts of CS‐P‐Co (≤ 4.0 wt%) show remarkably improved flame retardancy, such as decreased peak heat release rate and total heat release by 23.0% and 20.0%, respectively. Scanning electron microscopy, Thermogravimetric analysis, and Raman results demonstrate that compact graphitized char layers are formed on the composite surface during combustion, attributed to the catalytic effect of CS‐P‐Co. The char inhibits diffusion of heat, mass, and oxygen, which plays a key role in the flame retardancy enhancement. [ABSTRACT FROM AUTHOR]

A series of boron-nitrogen polymers (PEIPAs) were synthesized to provide a green alternative for flame retardant finishing on cotton fabrics. An organic boron compound, phenylboronic acid (PA) was successfully bonded to the branched polyethylenimine, which was confirmed by H NMR and FTIR analysis. Thermogravimetric analysis showed that the polymer with molar ratio 1:1 of ethylenimine:PA (PEIPA 1:1), presented the optimal thermal-oxidative stability. PEIPA 1:1 was easily applied on cotton fabrics through a simple dipping method with high uptake in acetone medium. The fabric with 33.8 wt% add-on got self-extinguishing ability. SEM analysis on the char morphology of the treated fabrics revealed the fire protection by the coating through intumescent flame retardant mechanism. TGIR analysis showed the coated fabric has significant reduction in the flammable volatiles production. Further improvement of the coating washing durability was achieved by a novel formaldehyde-free cross-linking treatment. The new washing stable coating achieved LOI values 29.6 and 23.2% before and after repeated launderings respectively with 30 wt% add-on. Cone calorimetry analysis showed that the total heat releases of PEIPA 1:1 treated sample and cross-linked sample (PEIPA 3:1/NeoFR treated) were decreased by 30.3 and 45.5% respectively. Smoke analysis revealed that the treated fabrics have significant decrease in CO/CO ratio, indicating an effective flame inhibition in gas phase. The novel coatings, simple to synthesize and easy to apply with low waste, are suitable alternative to toxic halogenated flame retardants for cellulosic products. [ABSTRACT FROM AUTHOR]

A new type of fire suppressant powders of magnesium hydroxide (Mg(OH) 2 ) modified by DOPO-VTS has been manufactured. And the fire suppression effectiveness and physical-chemical properties were studied in this paper. Three kinds of powders were used to study their fire suppression efficiency through laboratory scale experiments in a confine space of 1*1*1m. The physical and chemical characteristics of pure Mg(OH) 2 and its modified powder were characterized by thermal gravity analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results exhibited that these three kinds of powder were all high efficient for fire suppression and the modified Mg(OH) 2 powders by added 3% DOPO-VTS was more efficient than the Mg(OH) 2 powders added 1% DOPO-VTS and the origin powder. And the modified Mg(OH) 2 powder by added 3% DOPO-VTS could release the least CO and decrease the flame temperature sharply. Fire extinguishing and possible fire-suppression mechanisms have also been analyzed from three aspects: chemical inhibition, cooling effect and asphyxiation effect. [ABSTRACT FROM AUTHOR]

Low flame retardant efficiency is a key bottleneck for currently available retardants against the flammable polypropylene (PP). Herein, the organically modified montmorillonite (OMMT) was utilized as a synergist for our previously reported intumescent flame retardant (IFR) that was constructed from ammonium polyphosphate (APP) and hyperbranched charring foaming agent (HCFA) to further enhance the retardant efficiency against PP. The resultant's combustion behavior was thoroughly investigated by cone calorimetry, limiting oxygen index (LOI), vertical burning test (UL-94), and scanning electron microscopy (SEM). The results showed that 20% addition of IFR with OMMT showed a positive effect and improved the flame retardancy of the PP systems. Especially, addition of 2 wt% OMMT obviously increased the LOI values of PP systems with 20% total loading flame retardants from 29% to 31.5% and the samples meet V-0 rating as well as the reduction of the heat release rate (HRR), total heat release (THR), CO2, and CO production occurred. On the other hand, the SEM images were also revealed that OMMT initiated a dense and strong char on the surface of the material, which resulted in efficient flame retardancy of PP matrix during combustion. In addition, thermal degradation behavior discussed by thermogravimetric analysis (TGA) indicated that OMMT could improve the thermal stability of PP systems under high temperature, and promoted char residues of PP/IFR systems. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO3) microrods, nanofibers, and nanoplates were synthesized via the hydrothermal method and high-temperature calcination method, respectively. Then the MoO3 was added into polyurethane elastomer, respectively. The flame retardancy and smoke suppression of the composites added with different MoO3 were studied by thermal gravimetric analysis, cone calorimeter, and smoke density. The results show that the three kinds of MoO3 with different morphologies could promote the formation of char and possess flame retardancy and smoke suppression, and MoO3 nanofibers exhibit a higher degree of flame retardancy, and 1 wt% addition could make the peak heat release rate of polyurethane elastomer composites reduce from 881.6 kW m−2 for a pure sample to 343.4 kW m−2, a decrease by 61.0%. As for smoke suppression, MoO3 nanoplates possess the best smoke suppression; 5 wt% could decrease a pure sample's smoke density by 41.3% from 361 to 212. Moreover, the char residue of composites after combustion was analyzed by Raman spectra and X-ray photoelectron spectroscopy, and the flame retardancy and smoke suppression mechanisms of MoO3 were discussed. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is modified by melamine (MA) via the strong π- π interactions, hydrogen bonding, and electrostatic attraction. PP composites are prepared by melt compounding method, and GO/functionalized graphene oxide (FGO) is in situ thermally reduced during the processing. The results of scanning electron microscopy and transmission electron microscopy indicate that FGO nanosheets are homogeneously dispersed in polymer matrix with intercalation and exfoliation microstructure. The FGO/PP nanocomposite exhibits higher thermal stability and flame retardant property than those of the GO counterpart. During the thermal decomposition, the intercalated MA is condensed to graphitic carbon nitride (g-CN) in the confined micro-zone created by GO nanosheets. This in situ formed g-CN provides a protective layer to graphene and enhances its barrier effect. The heat release rate and the escape of volatile degradation products are reduced in the FGO-based nanocomposites. [ABSTRACT FROM AUTHOR]

A flame retardant nanocoating made from chitosan and titanate nanotubes was deposited on the surface of cotton fabric by the layer by layer assembly to improve its flame retardancy. Firstly, the hydrothermal method was used to prepare titanate nanotubes. Then, coated cotton fabrics were prepared by alternately submersing cotton fabrics into chitosan solution and titanate nanotube suspension. The structure of nanocoating on cotton fabric surface was tailored by altering number of bilayers and the concentration of titanate nanotube suspension. X-ray photoelectron spectroscopy confirmed that titanate nanotube filled nanocoating was successfully deposited on the surface of cotton fabric. Furthermore, the titanate nanotubes assembled a randomly oriented and entangled network structure, as can be observed by scanning electron microscopy. The thermogravimetric analysis result indicated that the thermal and thermal-oxidation stability of all coated cotton fabrics were both improved in the high temperature range from 330 to 700 °C. The microscale combustion calorimeter result showed that all coated cotton fabrics have the reduction in peak heat release rate and total heat release compared with that of pristine cotton fabric. Moreover, the reduction was dependent on the concentration of titanate nanotube suspension and number of bilayers. The improved flame retardancy can be ascribed to the protective effect of the titanate nanotube network structure formed, which acts as a physical barrier to retard the heat, oxygen and mass transfers between the flame and underlying material. [ABSTRACT FROM AUTHOR]

Organophilic α-zirconium phosphate (α-ZrP, OZrP) with a lamellar structure is used as a synergistic agent with aluminum hydroxide (ATH) to improve the flame retardancy of low-density polyethylene and ethylene-vinyl acetate (LDPE/EVA) hybrid. The structures of LDPE/EVA/(ATH, OZrP) hybrids are characterized by X-ray diffraction, transmission electron microscopy, and high resolution transmission electronic microscopy. The results indicate that the intercalated and exfoliated nanocomposites are formed. The flammability characterization and synergistic effects of LDPE/EVA/(ATH, OZrP) hybrids have been investigated by cone calorimeter test, limiting oxygen index, and UL-94 tests. The analyses show that hybrids with a given amount of OZrP have apparently reduced the heat release rates and can pass the V-0 rating in the UL-94 test. Based on these findings, a possible and reasonable synergistic flame retardant mechanism of OZrP and ATH is given in the discussion. [ABSTRACT FROM AUTHOR]

Polyelectrolytes multilayer (PEM) films based on fully biobased polysaccharides, chitosan and phosphorylated cellulose (PCL) were deposited on the surface of cotton fabric by the layer-by-layer assembly method. Altering the concentration of PCL could modify the final loading on the surface of cotton fabrics. A higher PCL concentration (2 wt%) could result in more loading. Attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis directly showed that chitosan and PCL were successfully deposited onto the surface of cotton fabric. In the vertical flame test, the cotton fabric with 20 bilayers at the higher PCL concentration (2 wt%) could extinguish the flame. Microcombustion calorimetry results showed that all coated cotton fabrics reduced the peak heat release rate (HRR) and total heat release (THR) relative to the pure one, especially for (CH0.5/PCL2), which showed the greatest reduction in peak HRR and THR. Thermogravimetric analysis results showed that the char residue at temperatures ranging from 400 to 700 °C was enhanced compared to that in the pure cotton fabric, especially in the case of higher PCL concentration (2 wt%). The work first provided a PEM film based on fully biobased polysaccharide, chitosan and PCL on cotton fabric to enhance its flame retardancy and thermal stability via the layer-by-layer assembly method. [ABSTRACT FROM AUTHOR]

Ethyl cellulose, a widely used bio-degradable shell material, microencapsulated ammonium polyphosphate (MAPP) was added to the bio-degradable poly(butylene succinate) (PBS) to improve its flame retardancy, compatibility, and thermal stability. The MAPP was well characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), water contact angle, and thermogravimetric (TG) analysis. The SEM results indicate the improved dispersion of MAPP into PBS matrix and the formation of the strong interfacial adhesion between MAPP and PBS than APP. With the incorporation of MAPP and char-forming agent into PBS, the limiting oxygen index of the composite was increased to 35.5 %, and the sample can pass the UL-94 V-0 rating, while the un-microencapsulated counterpart cannot reach the rating. The cone calorimeter test showed that the peak heat release rate was decreased by 46.7 % and the burning time was also prolonged compared to the pure PBS. The increased melt flow index and rheology test indicated the increase of viscosity and the improvement of anti-dripping properties. Moreover, the mechanical properties and thermal stability of MAPP composite were also obviously enhanced after the microencapsulation by mechanical, dynamical mechanical thermal analysis, and TG analysis. [ABSTRACT FROM AUTHOR]

In this paper, three typical transition metal phosphide nanocrystallines (MxPy, M = Ni, Co, and Cu) were synthesized by a novel hydrothermal method, and their structures were characterized by X-ray diffraction and transmission electron microscopy. Then they were used as synergistic agents with intumescent flame retardant (IFR) to improve the fire safety of polypropylene (PP). Thermogravimetry analysis (TGA) results indicated that the introduction of these synergists could improve the thermal stability and char yields of the PP/IFR system. The addition of 2 wt.% Ni12P5 and Co2P increased the limiting oxygen index values of the PP/IFR system significantly from 28% to 36% and 34%, respectively, and the system could reach V-0 rating. The cone calorimeter test results revealed that the combination of transition metal phosphide nanocrystallines and IFR system could result in excellent flame retardancy. The incorporation of these synergists into IFR led to a remarkable influence on charring of PP composites as revealed by TGA and cone data. The morphological structure of char residue proved that the addition of transition metal phosphide nanocrystallines was capable of forming a compact and homogeneous char on the surface, which turned out to be of most importance for the flame retardancy. Thermogravimetric analysis/infrared spectrometry results indicated that the flame retardant mechanism of PP/IFR/MxPy (M = Ni, Co, and Cu) system was in the condensed phase rather than in the gas phase. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A novel halogen‐free flame‐retardant material consisting of a novel cyclotriphosphazene‐based char‐forming agent, aluminum diethyl phosphinate, nickel trioxide (Ni2O3), an oil‐filled styrene–ethylene–butadiene–styrene block copolymer, and polypropylene was studied. On the basis of their UL‐94 ratings and limiting oxygen index (LOI) data, the flame retardants exhibited very effective flame‐retardant properties in the material. When the loading of flame retardant (FR) was only 35 wt %, the flame‐retardant material attained a UL‐94 V‐0 (1.6 mm) rating, and its LOI value reached 31%. The thermogravimetric analysis data indicated that the flame retardant effectively reduced the peak mass loss because of the formation of abundant char residue. Moreover, the flammability parameters of the material obtained from UL‐94, LOI, and cone calorimetry tests demonstrated that the fire safety performance of the material with Ni2O3 obviously improved. The morphological structure of the char residue of the material with the flame retardant and Ni2O3 showed a dense and continuous carbon layer. The high‐quality carbon layer formed on the surface of the polymer material matrix showed a heat‐insulating effect. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46888. [ABSTRACT FROM AUTHOR]

In this work, microcrystalline cellulose (MCC) treated polyamide 66 (PA66) textiles were coated with green and naturally abundant polysaccharides specifically, chitosan (CS) and sodium alginate (SA) together with phytic acid (PA) via layer by layer (LbL) deposition. The prime focus of such treatment was to intensify both the hydrophilic and flame retardant properties of PA66 fabric substrates. Subsequently, the prepared coatings were further subjected to cross-linking modification by dipping them into the barium (Ba) salt solution. Obtained results indicated that the MCC-modified PA66 exhibited a water contact angle (WCA) value of 00 and revealed a drop in peak heat release rate (pHRR) up to 31 % with complete suppression of melt-dripping. Meanwhile, the Ba-ion-induced cross-linking treatment further escalated this reduction up to 36 % by adding enhanced thermal stability, improved char quality along better wash durability of as prepared coatings. In addition, the combined modification of PA66 textiles with MCC and Ba-ion handed a superb enhancement of physical properties like tensile strength by ca. 50 % compared to the pure PA66. Thus, this MCC-assisted surface modification paves the way for a new kind of greener treatment of PA66 textiles in attaining superior hydrophilic and flame retardant properties of the same. • MCC-assisted surface engineering of PA66 fabrics was done. • Green polysaccharides were deposited on PA66 surfaces in LbL assembly. • MCC-modified and LbL deposited fabric surfaces exhibited superhydrophilicity. • MCC-modified and LbL deposited showed a substantial reduction in pHHR by 36 %. • Ba ion cross-linking helped to obtain superior wash durability to developed coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A core-shell structured piperazine pyrophosphate microcapsules (MT@PAPP) is constructed. • The MT@PAPP enhances the compatibility and mechanical property of TPE/MT@PAPP composites. • Compared with pure TPE, the PHRR and PSPR of TPE/MT@PAPP were reduced by 78.5% and 60.0%, respectively. In this study, core-shell structured piperazine pyrophosphate (PAPP) is designed to enhance the fire safety and mechanical property of styrenic thermoplastic elastomer (TPE) composites. The PAPP is microencapsulated with carbon nanotube modified melamine-formaldehyde resin to prepare core-shell structured flame retardants (MT@PAPP). Due to the excellent compatibility between the MT@PAPP and TPE matrix, the mechanical property of TPE/MT@PAPP is improved. Compared with TPE, the peak heat release rate and peak smoke production rate of TPE/MT@PAPP are decreased by 78.5% and 60.0%, respectively. Thus, the core-shell structured piperazine pyrophosphate microcapsule strategy provides an excellent approach to obtain high-performance TPE composites. [ABSTRACT FROM AUTHOR]

The fire hazard assessment of polymers and the effect of flame retardants constitutes the foundation for preventing and managing fire risks to public safety. This study addresses key challenges by considering intrinsic hazards, indicator volatility and correlations, while overcoming subjectivity in weight assignment and the neglect of flame-retardant treatments. Firstly, we initiate two novel steps of Pearson correlation analysis and predefined comparative scales for indicators, which enhance the objectivity, scalability and repeatability of analytic network process (ANP) weights. Secondly, we utilize the CRITIC method to incorporate indicator volatility and correlations, surpassing the limitations of separate calculations and subsequent combinations. The newly developed pure sample normalization method enhances the interpretability and scientific validity of CRITIC weights. Combining the ANP and CRITIC weights using Nash equilibrium theory, the results rectify the underestimated T -5% from 0.72% to 3.64%, reducing the overestimated PCO 2 , PSP and TSP from 11.98%, 9.62% and 9.59–7.25%, 9.12% and 5.69%, respectively. Finally, the fire hazards value effectively captures the increased fire hazards resulting from specific degraded indicators following flame retardant treatments. The research findings provide a fresh perspective for the safe design of flame-retardant polymers and fire hazard assessment, offering valuable insights for fire risk prevention and management. [ABSTRACT FROM AUTHOR]

• A syringaldehyde derived epoxy resin monomer (SA-TAG-EP) was developed. • The bio-based epoxy system showed a record T g of 224 °C, high strength and modulus. • The bio-based epoxy system showed satisfactory intrinsic flame retardancy. Due to increasing environmental concerns, global warming, and the decline of oil reservoirs, the use of bio-epoxy resins derived from sustainable resources is recommended. The development of bio-based epoxy resins with considerable thermal stability, mechanical strength, and appropriate intrinsic flame retardant potential is highly demanded. In this study, a new Schiff-based epoxy monomer, triglycidyl ether of syringaldehyde (SA-TAG-EP), was synthesized from renewable syringaldehyde. After the 4,4′-diaminodiphenylmethane (DDM)-based curing process, an intrinsically flame-retardant resin (SA-TAG-EP/DDM) with C, H, N, and O elements was achieved. SA-TAG-EP/DDM showed higher glass transition temperature (224.9°C) and greater mechanical strength, including a tensile strength of 66.8 MPa and an elongation at break of 3.91%, compared to petroleum-based bisphenol A epoxy thermoset. It also passed the V-0 flammability rating in the UL-94 test and exhibited a 38.5% limiting oxygen index, 48.9% char yield under N 2 , and a lower peak heat release rate than that of petroleum-based bisphenol A epoxy thermoset. We proposed a simple and sustainable route for the synthesis of Schiff base epoxy compounds from biomass-derived resources, which demonstrates significant mechanical properties and increased flame retardant potential. [ABSTRACT FROM AUTHOR]

A novel polymeric flame retardant poly (pentaerythritol phosphate phosphinic acyl piperazine) (PPAP) was synthesized successfully. The structure was confirmed by Fourier transform infrared spectra (FT-IR) and nuclear magnetic resonance spectra (NMR). The flame retardant property was characterized by limited oxygen index (LOI) and cone calorimetry test. Compared with 19% of epoxy resin, the LOI value of epoxy resin/PPAP composites (EP/PPAP) could reach high up to 35% when PPAP content was 20 wt % (EP-4) and the photographs of char residues demonstrated excellent char-forming ability of PPAP. The increasing char residues in thermogravimetric analysis (TGA) and analyses of real time FT-IR (RT-FTIR) showed improved thermal stabilities of EP/PPAP composites. The formation of enhanced stable char layer were proved by FT-IR, scanning electron microscopy (SEM) and Raman spectroscopy. The dynamic mechanical properties of EP/PPAP composites such as storage modulus and crosslinking density were substantially enhanced. [ABSTRACT FROM AUTHOR]

A novel flame‐retardant unsaturated polyester (UP) was obtained by introducing ammonium polyphosphate (APP) and aluminum hypophosphite (AHP) into UP matrix. The UP/APP/AHP composites obtained were characterized by Fourier Transform Infrared Spectra (FTIR). From limiting oxygen index (LOI), microscale combustion calorimetry (MCC), and UL‐94 tests, the UP/APP/AHP composites present significantly enhanced flame retardancy when compared to pure UP, such as passed UL‐94 V‐0 classification, decreased peak heat release rate (PHRR) maximally by 50.0% and total heat release (THR) maximally by 22.0%, and increased LOI by 34.8%. Thermal degradation behaviors of composites studied by thermogravimetric analysis (TGA) suggest that APP/AHP hybrids have a higher catalytic charring efficiency than APP alone. Char morphology investigated by scanning electron microscopy (SEM) indicates that the UP/APP/AHP composites form a compact and intumescent char on the sample surface during combustion, which could retard the transfer of heat and oxygen. Thermogravimetric analysis/infrared spectrometry (TGIR) results reveal that the APP/AHP hybrids reduce the release amount of combustible gas from polymer matrix during combustion. The UP/APP/AHP system acts in gas phase through flame inhibition and in condensed phase through charring, resulting in significantly enhanced flame retardancy. This work combining condensed‐phase mechanisms with gas‐phase mechanisms in flame retardance of UP would stimulate more efforts to explore highly effective flame‐retardant system of polymers. POLYM. COMPOS., 39:1763–1770, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

[Display omitted] • FPUF composites was formed after the introduction of Ti 3 C 2 T x @BPA@PCL and DH-DOPO. • Compression strength of FPUF-DH-Ti 3 C 2 T x @BPA@PCL are increased by 253% and is highly fatigue-resistance. • 36.1% and 44.0% reductions in pHRR and THR of FPUF-DH-Ti 3 C 2 T x @BPA@PCL are achieved. • FPUF-DH-Ti 3 C 2 T x @BPA@PCL is self-extinguished and passes the vertical burning test. It is of great importance to fabricate flexible polyurethane foam (FPUF) with superior mechanical properties and flame retardancy for practical applications. Herein, organosilicon and phenyl phosphorus compounds were synthesized and grafted on the surface of Ti 3 C 2 T x (Ti 3 C 2 T x @BPA@PCL) via in-situ polymerization. Then, the FPUF composites were fabricated, combining intrinsic flame retardancy (9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide-diethanolamine: DH-DOPO) (addition amount: 20 wt%) and Ti 3 C 2 T x @BPA@PCL (addition amount: 4 wt%). Attributed to the rigid structure of Ti 3 C 2 T x @BPA@PCL, the tensile strength and compression strength of FPUF showed 24.0% and 253% increase, respectively. In addition, anti-fatigue properties of FPUF composites during the cyclical test were dramatically enhanced. In contrast to pure FPUF, 36.1% and 44.0% reductions in peak heat release rate (pHRR) and total heat release (THR) were achieved for the FPUF containing Ti 3 C 2 T x @BPA@PCL and DH-DOPO, the production rate of carbon dioxide (CO 2) and carbon oxide (CO) also decreased by 40.3% and 52.1%, respectively. FPUF4 showed self-extinguishing behavior, and passed the vertical burning test (VBT). This work provides a facile approach to preparing high-performance FPUF with enhanced mechanical property and flame retardancy. [ABSTRACT FROM AUTHOR]

[Display omitted] Aiming at enhancing the toughness and fire safety of bismaleimide (BMI), BMI monomers containing phosphate and phosphonate structure (BDTP and BDTDP) were designed and prepared. With incorporation of 5 wt% BDTP and BDTDP, the peak value of heat release rate (PHRR) of BMI/BDTP-5 and BMI/BDTDP-5 decrease by 59.4% and 52.4%, respectively. The total smoke production (TSP) of BMI/BDTP-5 and BMI/BDTDP-5 are of 8.3% and 13.1% reduction, respectively. Meanwhile, BMI/BDTP-5 and BMI/BDTDP-5 possess UL-94V-0 rating, which indicates that BMI is endowed with better flame retardant performance by modification of designed BMI monomers. Besides, the impact strength of BMI/BDTP-5 and BMI/BDTDP-5 increase by 146.3% and 90.2%, respectively. The comprehensive performance of BMI/BDTP-5 is better than that of BMI/BDTDP-5. And the effect of phenyl phosphate structure in BDTP and phenyl phosphonate structure in BDTDP on BMI performance is explored. [ABSTRACT FROM AUTHOR]

• A series of coatings with high transparency and excellent pencil hardness levels were prepared on polycarbonate (PC) substrates via a two-step UV-curing process with TAEP and MAAR. • The coupling effect of the combustion behaviours of the UV-cured coatings and the PC substrates was particularly investigated to give insight into a holistic picture of the combustion of the coated PC composites. • The composite UV-cured coatings successfully suppressed the heat release and improved the flame retardancy of the PC samples thanks to the phosphorus-nitrogen synergistic flame-retardant effect in the condensed phase. • A potential strategy to further enhance the flame-retardant ability of the UV-cured coatings lies in improving the thermal and mechanical stabilities of the intumescent char layers. There is an urgent demand for flame retardant treatment of polycarbonate (PC) with as little adverse impact on the inherent advantages of PC as possible, especially the high transparency. Herein, a flame-retardant coating with high transparency was successfully prepared on PC via a two-step ultraviolet-curing (UV-curing) process with tri(acryloyloxyethyl) phosphate and melamine acrylate resin. All the coated PC composites showed high transparency and excellent pencil hardness levels (6H). The coupling effect of the combustion behaviours of the UV-cured coatings and the PC substrates was particularly investigated to give insight into a holistic picture of the combustion of the coated composite systems. Specifically, all the composite UV-cured coating samples (T2M1, T1M1 and T1M2) formed highly expanded char with honeycomb-like inner structure due to the phosphorus-nitrogen synergistic effects, which could efficiently suppress mass and heat transfer, thereby protecting the PC substrates from the harsh conditions of high temperature and realizing significantly enhanced flame retardancy of the PC samples. Improving the thermal and mechanical stabilities of the intumescent carbon layers may be a practical strategy to achieve further improved flame retardant capabilities of the PC samples. Additionally, the PC-T2M1 composite exhibited the optimal flame retardant effect, realizing significantly suppressed heat release in the cone calorimeter tests, reaching UL94 V-0 rating and showing long fire resistance time thanks to the intumescent char. The UV-cured coating method introduced in this work had great potential in spawning new strategies for designing advanced flame retardant coatings for polymer substrates. [Display omitted] [ABSTRACT FROM AUTHOR]

Due to the high polarizability of traditional flame retardants, it is difficult to meet the excellent dielectric properties and flame retardancy required for electronic packaging materials. Therefore, we have designed a novel linear polyphosphazene that can balance the dielectric properties and flame retardancy of bismaleimide (BMI) composites. Here, fluorinated aromatic ring structure with the large freedom volume is connected to the main chain of polydichlorophosphazene (PDCP) as a side group, resulting in multifunctional fluorinated linear polyphosphazene (PBTFP). Attributed to the excellent P/N/F combination flame retardant strategy, extremely low polarizability, and large molecular free volume, PBTFP simultaneously improves the dielectric properties and flame retardancy of the BMI composites, including UL-94 rating of V0, and a dielectric constant (D k) as low as 2.69. In addition, as an elastomer, PBTFP exhibits positive effects on improving the hydrophobicity and toughness of BMI. Therefore, through a simple affinity substitution reaction, we prepared a multifunctional fluorinated linear polyphosphazene modified BMI based electronic packaging substrate material that can be applied to 5G high-frequency communication. [Display omitted] [ABSTRACT FROM AUTHOR]

• The fire-proof TD-GPE with + 3 and + 5 phosphorus valence states was synthesized via in-situ polymerization. • The TD-GPE shows highly stable cycle performance for NCM811 and LFP full soft pack batteries (1 Ah). • The "jet fire" and leakage were suppressed in the thermal abuse test of NCM811 battery by using flame-retardant TD-GPE. Lithium-ion batteries (LIBs) have been widely used today owing to portability, high energy storage, and reusability. However, commercial liquid electrolytes in LIBs possess intensive mobility and terrible flammability. Accordingly, leakage, combusting, and even exploding can frequently occur when LIBs work under abuse conditions. Herein, a novel flame-retardant gel polymer electrolyte (GPE) containing + 3 and + 5 phosphorus valence states of phosphorus structures was designed by in-situ thermal polymerization of tri(acryloyloxyethyl) phosphate (TAEP), diethyl vinylphosphonate (DEVP), and pentaerythritol tetraacrylate in electrolytes. After being ignited by fire, this GPE extinguished quickly with a combusting time of only 0.9 s, showing much lower flammability. Besides, the GPE is compatible with graphite anode, LiFePO 4 (LFP), and even LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathodes. The as-assembled LFP and NCM811-based pouch cells (1 Ah-type) with TD-GPE achieved stable cycling, maintaining 88.52 % and 95.2 % of the initial capacities, respectively after 200 and 190 cycles at 0.5C. Moreover, the as-prepared TD-GPE dramatically reduced the fire hazard of NCM811 batteries without sacrificing the electrochemical performance. The thermal abuse test demonstrates that the leakage and combustion of NCM811||TD-GPE||Graphite pouch cell could be significantly suppressed in the test process, indicating that battery safety improves significantly via the combined use of different phosphorus valence structures. This is because the + 5 phosphorus valence of TAEP promoted the formation of carbon layers, and the + 3 phosphorus structure in DEVP captured free radicals by quenching effect. This work paves a different path for designing safe and high-performance GPEs in LIBs based on gaseous-phase and condensed-phase mechanisms. [ABSTRACT FROM AUTHOR]

A synergistic flame retardant with a core-shell structure utilizes the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative as the outer shell and ammonium polyphosphate (APP) as the inner core. Three derivatives of DOPO (DOPO-GY, DOPO-DH and DOPO-GD) are synthesized by reacting DOPO with glyoxal, paraformaldehyde and diethanolamine, and glutaraldehyde, respectively. DOPO-GY@APP, DOPO-DH@APP and DOPO-GD@APP exhibit good radical scavenging activities. The oxidation induction time for EVA/DOPO-GY@APP is exceptionally high at 19.04 min, in contrast to EVA alone, which has an induction time of only 5.51 min. Simultaneously, after aging at 180 °C and 165 °C for 7 days, the retention rates of elongation at break for EVA/DOPO-GY@APP are 34.67 % and 55.50 %, respectively. These findings demonstrate the long-term anti-aging properties of EVA/DOPO-GY@APP without the need for additional antioxidants. Moreover, EVA/DOPO-GY@APP, EVA/DOPO-DH@APP and EVA/DOPO-GD@APP all achieve V-0 rating with 25 % addition of flame retardant. In comparison to pure EVA, their peak heat release rates and maximum smoke density decrease by 52 % and 47 %, 43 % and 54 %, and 51 % and 44 %, respectively. Additionally, compared to EVA/APP, their mechanical properties have been improved. Therefore, these microencapsulated flame retardants with DOPO derivatives as the shell effectively enhance the mechanical properties and fire safety of EVA composites. [Display omitted] • A multifunctional microencapsulated flame retardant is successfully designed. • The DOPO-GY@APP shows good radical scavenging activities. • The retention rate of EB from EVA/DOPO-GY@APP can reach 55.50 % after aging at 165 °C for 7 days. • EVA/DOPO-GY@APP reveal anti-aging properties without adding any antioxidant. • The pHRR and Ds max of EVA/DOPO-GY@APP are reduced by 52 % and 47 %, respectively. [ABSTRACT FROM AUTHOR]

Fire hazards are a primary concern in aircraft accidents, and controlling combustible materials is pivotal in managing cabin fire risks. This work aims to elucidate the impact of widespread measures that introduce phosphorus-based flame retardants (PFRs) on the fire safety of carbon fiber epoxy composites (CF/EP). Firstly, the hazardous indicators for flame retardant CF/EP composites exhibit two categories of optimization and degradation, which are caused by the intrinsic feature, pyrolysis characteristics and chemical valence states of PFRs. Secondly, the fire hazards of composites are assessed by fusing the analytic network process and information weights guided by Nash Equilibrium theory. The method combines the merits of subjective and objective weights from dimensions of intrinsic hazards, interrelationships and data dispersion of indicators. Finally, the assessed fire hazard rankings under 35 and 65 kW/m2 both are EP > CF/EP16%DOPO-HQ > CF/EP > CF/EP7%DPO. In conclusion, DOPO-HQ (+1) primarily increases the fire hazard of CF/EP due to gas-phase flame-retardant effects, while DPO (+3) predominantly reduces the fire hazard of CF/EP by contributing to condensed-phase effects. This work highlights the contradictory effects of PFRs on the fire safety of CF/EP composites due to structure and thermal stability. The proposed ANP and IW hybridization method provides a theoretical foundation for selecting flame retardants and assessing material fire hazards comprehensively. [ABSTRACT FROM AUTHOR]