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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]

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]

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]

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]

Although hexagonal boron nitride (h‐BN) has presented a potential prospect in polymer composite fields, undesirable interfacial interaction with polymer matrix that generates serious aggregation of nanomaterials has suppressed its enhancement effect. Moreover, the chemically inert surface of h‐BN also makes the commonly used approach that improves the interfacial interaction between nanofillers and polymeric matrix invalid. Herein, the functionalized modification of chemically inert h‐BN was successfully fabricated by the adsorption of cetyl‐trimethylammonium bromide, with electrostatic interactions. The obtained h‐BN (cetyl‐trimethylammonium bromide‐BN) was well characterized by systematic tests and then added into thermoplastic polyurethane (TPU) matrix. The inclusion of functionalized h‐BN can dramatically improve thermal stability, flame retardant, and mechanical properties of TPU composites. With the incorporation of as low as 4.0 wt% nanofillers, maximal value of heat release rate and total heat release of TPU were reduced by 57.5% and 17.8%, compared with those of pure TPU, respectively. Moreover, tensile strength of TPU composite with a loading of 2.0 wt% was increased by 79.3% in comparison with that of neat TPU. The facile functionalized approach of chemically inert h‐BN paves the way for promising applications of h‐BN in the development of flame retardant polymer materials. [ABSTRACT FROM AUTHOR]

In this work, a novel hyperbranched and phosphorus‐containing triazine derivative (HPCFA) is synthesized. HPCFA is used as charring‐foaming agent and combined with ammonium polyphosphate (APP) as intumescent flame retardant to flame retard polypropylene (PP). PP/HPCFA/APP composite can achieve limited oxygen index value of 31% and pass UL 94V‐0 rating by addition of 20 wt% HPCFA/APP (1/2, w/w). Besides, HPCFA is compared with another hyperbranched charring‐foaming agent (HCFA). HPCFA and HCFA have similar chemical structure, and their only difference is that HPCFA has phosphorus‐containing unit in the main chain compared with HCFA. HPCFA/APP system exhibits superior flame retardancy compared with HCFA/APP system. Char residue analysis demonstrates that HPCFA/APP system can form denser and more compact char layer in comparison with that of HCFA/APP system. [ABSTRACT FROM AUTHOR]

Magnesium hydroxystannate [MgSn(OH)6, MgHS] was successfully prepared by a facile coprecipitation method. Then, MgHS was used to intumescent flame-retardant polypropylene systems. Thermogravimetry analysis results indicated that the introduction of MgHS can improve the thermal stability of the intumescent flame-retardant polypropylene system. Limiting oxygen index and UL-94 vertical burning test data show that the addition of MgHS can significantly improve the flame retardancy of intumescent flame-retardant polypropylene system. From the cone calorimetry results, it can be observed that the peak heat release rate is decreased in comparison with intumescent flame-retardant polypropylene. Moreover, the addition of MgHS significantly reduced the gaseous products, especially carbon monoxide. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of flame retarding rigid polyurethane foam (RPUF) composites based on expandable graphite (EG) and aluminum hypophosphite (AHP) were prepared by the one-pot method. The properties were characterized by limiting oxygen index (LOI) test, cone calorimeter test, thermogravimetric analysis (TGA), real-time Fourier transform-infrared spectra (RT-FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), etc. The results indicate that both EG and AHP could enhance the flame retardency of RPUF composites. Besides, the flame retardant effect of EG was better than that of AHP. The results also show that partial substitution of EG with AHP could improve the flame retardency of RPUF, and EG and AHP presented an excellent synergistic effect on flame retardancy. What is more, compared with RPUF/20EG and RPUF/20AHP, the heat release rate (HRR) and total heat release (THR) of RPUF/15EG/5AHP were lower.TGA results indicate that partial substitution of EG with AHP could improve the char residue which provided better flame retardancy for RPUF composites. The thermal degradation process of RPUF composites and the chemical component of the char residue were investigated by RT-FT-IR and XPS. And the results prove that RPUF/15EG/5AHP had higher heat resistance in the later stage. Compared with the RPUF composites filled with EG, a better cell structure and mechanical properties were observed with the substitution of AHP for part of EG. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42842. [ABSTRACT FROM AUTHOR]

ABSTRACT Microsphere aluminum hypophosphite (AHP) is prepared via the hydrothermal method and characterized by Fourier transform infrared spectrometry, X-ray diffraction, and scanning electron microscopy. Then the hydrothermal AHP and the precipitation AHP are added to the polyurethane elastomer (PUE). The flame retardant properties, thermal stability, and mechanical properties of the PUE with different kinds of AHP added are studied. The results show that the hydrothermal AHP is microsphere with a uniform particle size of around 5 µm. The limited oxygen index of the PUE with the addition of 5% hydrothermal AHP increases to 28.5 vol %. Compared with the PUE including different kinds of AHP, the peak heat release rate of added hydrothermal AHP decreases by about 6%. Hydrothermal AHP could improve the char yield which provides better flame retardancy for PUE. Meanwhile, the hydrothermal AHP-added PUE has better mechanical properties than that with precipitation AHP added. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42370. [ABSTRACT FROM AUTHOR]

This work aimed to study the influence of γ-irradiation on the mechanical and thermal properties of flame retardant EVA/LDPE/ATH blends. Flame retardant poly(ethylene vinyl acetate)/low-density polyethylene/aluminum hydroxide (EVA/LDPE/ATH) blends were prepared, with a LOI value of 40 % and UL-94 V0 rating. The influence of different γ-irradiation levels on flammability as well as mechanical, electrical, and thermal properties of EVA/LDPE/ATH blends was investigated. The flame resistance of EVA/LDPE/ATH blends was found to be slightly improved after γ-irradiation, and meanwhile the mechanical, electrical, and thermal properties were all enhanced due to the increase of cross-linking density. Moreover, thermogravimetric analysis/infrared spectra (TG-IR) were used to explore the thermal degradation process of the EVA/LDPE blends. TG-IR results indicated that the thermal degradation of EVA/LDPE/ATH blends was delayed after γ-irradiation, and the reduced pyrolysis products amounts were responsible for the improved fire resistance and thermal stability. [ABSTRACT FROM AUTHOR]

Eco-friendly thermally insulating cellulose aerogels made from environmentally friendly resources are very attractive in materials chemistry, but the high flammability limits their application. Herein, a novel phosphorus-containing flame retardant modifying agent (DOPO-IA) was incorporated into the cellulose nanofiber aerogel and the cellulose composite aerogels were prepared by esterification and followed by a freeze-drying process. The thermal conductivity of the resultant cellulose composite aerogels was in the range of 28.6–31.2 mW/(mK). Meanwhile, the cellulose aerogels modified with DOPO-IA showed significantly enhanced thermal stability, mechanical property, and flame retardant performance compared with the pure cellulose aerogel. The CNF-DI-3 showed a high char residue (19.8 wt%) at 700 °C, which was 187% higher than CNF. Specifically, CNF-DI-3 exhibited remarkable reductions in its PHRR and THR values which were 67% and 60%, respectively, as compared to those of CNF. In summary, it is of significance to synthesize mechanically robust and flame-retardant cellulose aerogels. [Display omitted] [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]

In this article, MMT (montmorillonite) and ABS (acrylonitrile butadiene styrene) blends were prepared via melt blending process using a twin‐screw extruder. Differences of flame spread characteristics and smoke toxicity with addition of MMT was analyzed. Flame spread properties of materials with different geometric dimension and the side covering degree were investigated with a high definition digital camera and image processing technology. Smoke toxicity under different ventilation condition were studied using a steady state tube furnace (BS 7900, ISO TS 19700). The addition of MMT remarkably reduced the flame spread rate of ABS especially for burning without sidewall. In well‐ventilated conditions, MMT increase the toxicity of the effluent by increasing the CO yield. In under‐ventilated conditions, the FED values of two materials were almost same. POLYM. COMPOS., 39:1234–1241, 2018. © 2016 Society of Plastics Engineers [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]

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]

[Display omitted] • A flame-retardant and photo-thermal microstructure is synthesized. • Thermochromic materials and bio-based flame retardants are used as core and shell. • Heat release and smoke production are effectively suppressed. • The melting and slide of ice block is accelerated by solar-thermal conversion. Due to the extreme dynamic weather, important industrial facilities and infrastructure providing vital support for people's lives usually face the hazards of fire and icing, especially in the weather of thunderstorm and ice. Therefore, to further establish a safe community, we develop a dual-functional polyurea (PUA) coating used as protective materials by introducing flame retardancy and solar de-icing performance. Based on the microencapsulation and electrostatic self-assembly technologies, flame-retardant and thermochromic microcapsules (TCM) are firstly prepared and then added into PUA resin, by using melamine resin and bio-based phytic acid/chitosan (PA/CS) hybrids as double-shell materials. The high phosphorus content of PA and the carbon-forming effect of CS together play a synergistic flame retardant effect, not only improving the thermal stability of microcapsules but also enhancing the flame retardant property of PUA coating. In the cone calorimetry test, the ignition time of TCM@PA/CS@PUA-3 is longer, and the pHRR is reduced by 19.93 %, which shows the improvement of flame retardant performance. Due to the thermochromic mechanism, TCM@PA/CS@PUA composite coatings are able to adjust the photo-thermal conversion ability according to different environment temperature, achieving less temperature in hot environment and higher temperature in cold environment. The excellent photo-thermal conversion ability also promotes the ice melting and slide in 525 s. This polyurea composite coating with both flame retardant and de-icing properties shows great potential for maintaining the normal operation and safety of outdoor industrials and infrastructure in extremely dynamic weather conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • This work focuses on the sustainability and safety of radiative cooling materials. • Bio-based chitosan and phytic acid are used to prepare radiative cooling film. • The radiative cooling effect and fireproof performance are presented simultaneously. Even though significant advantages in the energy-free regulation of temperature are presented, the practical applications of radiative cooling materials in buildings and human surfaces still involve many safety issues, especially for fire hazards of polymer-based materials. Meanwhile, renewable and environmentally friendly materials are urgently needed to develop suitable radiative cooling materials with no adverse environmental impact. Herein, a chitosan-derived composite aerogel film with high solar reflection provided by the addition of melamine-phytic acid (MA/PA) hybrids is designed and prepared, presenting radiative cooling and fireproof performances. The instinct deep-yellow color of chitosan (CS) is successfully shielded by high-reflective MA/PA hybrids, while IR emissivity of up to 90.4 % and solar reflectivity of ∼ 89.3 % are achieved. In outdoor environments, this composite aerogel shows sub-ambient temperature drops of ∼ 4.3 °C and ∼ 3.1 °C in cloudless and cloudy weather, presenting a robust cooling effect. In addition, CS-MA/PA composite aerogel film with 3 mm thickness can isolate the fire of ∼ 500 °C, showing superior fire safety attributed to the synergistic flame retardant effects among chitosan, phytic acid, and melamine, which suppress the initial growth of fire and promote the rapid formation of protective char layer. This work provides a bio-based, fire-safe, and radiative cooling material to decrease the energy consumption of temperature regulation with a more environmentally friendly and safer approach, further promoting the practical application of radiative cooling materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZIF-8@Ti 3 C 2 T x was synthesised and applied to prepare flame-retardant flexible polyurethane foam composites. • Flame-retardant flexible polyurethane foam composites displayed excellent heat and toxic gases suppression performance. • Flame-retardant flexible polyurethane foam composites showed notable mechanical properties during compression and tensile tests. • The flame-retardant mechanism of ZIF-8@Ti 3 C 2 T x was systematically explored through gas and condensed products. Flexible polyurethane foam (FPUF) is the most used polyurethane, but the highly flammable characteristic limits its widespread usage. In this work, ZIF-8@Ti 3 C 2 T x was synthesized to reduce the heat and toxic gases of FPUF. Flame-retardant FPUF was characterized by cone calorimeter (Cone), thermogravimetric analysis/fourier-transform infrared spectroscopy (TG-FTIR), tensile and compression tests. Compared with pure FPUF, these results showed that the peak of heat release rate (PHRR), total heat release (THR), CO and HCN of FPUF6 decreased by 46%, 69%, 27% and 43.5%, respectively. Moreover, the tensile and compression strength of FPUF6 demonstrated a 52% and 130% increment, respectively. The superior dual metal catalytical charring-forming effect and physical barrier effect of ZIF-8@Ti 3 C 2 T x were achieved. In summary, a simple and reliable strategy for preparing flame-retardant FPUF with reinforced mechanical and fire safety properties was provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • The free switch of passive radiation cooling and solar thermal conversion is realized. • An average temperature drop of ∼5.62 °C is achieved under the hot environment. • A temperature increase of 28.3 °C is achieved under the cold environment. • The fire hazards of materials designed are suppressed significantly. Seasonable and spontaneous replacement approach of daytime radiative cooling to solar thermal conversion is challenging yet imperative for year-round thermal management materials. Meanwhile, the fire safety of thermal management materials is extremely important but often overlooked. Herein, we report a bio-inspired and fireproof aerogel presenting dynamically self-switchable ability of daytime radiative cooling and solar thermal conversion, composed of thermochromic microcapsules (TC), boron nitride nanosheets (BN), and bio-based materials (alginate and phytate). In hot environments, TC/BN composite aerogel shows solar reflectivity of 91.8 % and IR emissivity of 84.3 %, promoting heat radiation to outer space and achieving an average temperature drop of ∼5.62 °C. Attributed to the thermochromic mechanism, TC/BN composite aerogel can harvest visible light of 87 % in the solar spectrum to increase the material temperature by 28.3 °C, under an environment of −8.8 °C. Based on the EnergyPlus simulation, the employment of TC/BN composite aerogel contributes to decreasing the energy consumption of buildings in both hot and cold regions, including Cairo, Singapore, Alaska, Yakutsk, and so on. Besides, the peak values of heat release rate and total heat release during the combustion of TC/BN composite aerogels are significantly decreased by 70.6 % and 58.4 %, compared to those of TC composite aerogel. The produced protective char layer enhanced by BN nanosheets is capable of isolating the fire and suppressing the fire propagation, improving the fire safety of composite aerogels designed. The TC/BN composite aerogels provide a smart thermal regulation mode for radiative cooling and solar heating, overcome the problems from changing weather and environment, and significantly promote the practical application by enhanced fire safety. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual network interpenetration strategy significantly improves impact toughness. • Exceptional fire shielding performances, ∼32.8 % reduction in total heat release. • 48.4% decrease in total smoke production and LOI of 34.5% are achieved. • The optimized composite material has a dielectric constant as low as 2.67. The high-frequency transmission of 5th-Generation Mobile Communication Technology (5G) and more integrated mobile terminals pose a challenge to the safety and dielectric properties of existing electronic packaging materials. This work innovatively designs a linear polyphosphazene compound (PABN) with benzonitrile as the reactive side group. The prepared bismaleimide (BMI)/PABN is an excellent dielectric composite material, breaking the technical barrier of balancing fire safety and dielectric performance. With only 1 wt% PABN, the UL94 rating of BMI composite reaches V0, and the impact strength increases by 48.5 %, demonstrating excellent fire safety and toughness. Specifically, the dielectric constant (D k) of the composite containing 4 wt% PABN is as low as 2.67, far meeting the requirements of 5G. In addition, the glass transition temperature (Tg) of all BMI/PABN composites is around 290 °C, and the initial decomposition temperature exceeds 400 °C, indicating potential applications in the integration and miniaturization of microelectronic devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cardanol was applied to capture excess carbon dioxide from industry. • The bio-based NIPUs were synthesized from cardanol and carbon dioxide. • The comprehensive improvement effect of +5 valence of P was better than that of +3. • The modification of the intrinsic structure achieved eminent adhesion performance. Under the background of fossil fuel depletion and global warming, the large amount of carbon dioxide (CO 2) produced by industrial production was a renewable, clean and natural C1 feedstock that was becoming an ideal feedstock to produce value-added chemicals. The synthesis of non-isocyanate polyurethanes (NIPU) from cyclic carbonates as intermediate products was a typical way to realize the efficient recycling of CO 2. To improve the low carbonization, flammability and poor mechanics of NIPU and expand its application scenarios, the NIPU was synthesized from biological cardanol and CO 2 by a relatively green synthesis route, and modified by flame retardants containing different valence phosphorus. Compared with ECH-CarCO 2 -HMDA, the char residue of PO-CarCO 2 -HMDA and PP-CarCO 2 -HMDA increased by 248.8 % and 172.7 % respectively under nitrogen atmosphere, and 345.7 % and 151.9 % respectively under air atmosphere. More importantly, the peaks of heat release rate of modified NIPUs were reduced by 30.0 % and 18.4 %, and their total heat release were decreased by 15.2 % and 10.4 %, respectively. After various characterization analysis, this was mainly due to the generation of heat-stable structure containing phosphorus and oxygen during the burning process. Simultaneously, the toughness of PO-CarCO 2 -HMDA and PP-CarCO 2 -HMDA increased by 261.0 % and 105.1 %. In addition, the synthetic NIPU as an adhesive in different materials was also explored, and the adhesion strength can reach 2.47 MPa. This study provided a new idea for preparing bio-based NIPU which was more widely used. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultra-microporous COF-N with flame retardant, dielectric and toughening properties. • Cleverly designed to balance flame retardancy and dielectric properties. • ∼37.9 % reduction in PHRR and ∼55.6 % decrease in TSP. • The optimized composite material has a dielectric constant as low as 2.76. Most common flame retardants have high polarizability, so introducing flame retardants with simple structures to simultaneously improve the flame retardancy and dielectric properties of bismaleimide resin is a technical challenge. This work utilized the unique microporous structure of covalent organic framework (COF) as a low dielectric factor combined with molecular design to synthesize phosphonitrile based COF-N with a pore size of approximately 1.8 nm. The dielectric constant (D k) of BMI composite containing 1 wt% COF-N (BMI/COF-N 1.0) is as low as 2.76, far exceeding the requirement of less than 3. Moreover, BMI/COF-N 1.0 achieved UL94 at V0 rating, with a 37.9 % reduction in total heat release (THR) and a 55.6 % reduction in total smoke production (TSP), demonstrating excellent fire safety. In addition, the glass transition temperature (Tg) exceeds 290 ℃, which is greater than the heat resistance required for lead-free reflow soldering at 260 ℃. Therefore, a simple method is provided to prepare high-performance BMI based electronic packaging substrates. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three copper salt decorated graphene hybrids were successfully synthesized (rGO@CuO, rGO@Cu 2 O and rGO@CSOH). • Copper salt hybrids impart hybrid FPUF with excellent tensile, compression and buffering performance. • The hybrid FPUF reveals excellent flame retardancy and smoke suppression properties. • The rGO@CSOH shows a significant decreasement in reducing the heat hazard of hybrid FPUF. • The rGO@Cu 2 O demonstrates excellent smoke and toxic gases suppression in hybrid FPUF. Flexible polyurethane foam (FPUF) is the most commonly used polyurethane, but its highly flammable characteristics makes it ignite easily and release a lot of heat and toxic gases. Here, the effect of different forms of copper salt modified graphene (rGO@CuO, rGO@Cu 2 O and rGO@CSOH) on improving the fire protection efficiency and mechanical property of FPUF is explored. Hybrid FPUF is characterized by thermogravimetric analysis (TGA), cone calorimeter, thermogravimetric analysis/Fourier transform infrared spectroscopy (TG-IR), tension, compression, and falling ball rebound testing. Compared with pure FPUF, the FPUF/rGO@CSOH show a significant decreasement in reducing the heat release of FPUF, the PHRR and THR are reduced by 36.9% and 29.4%, respectively. While the FPUF/rGO@Cu 2 O demonstrate excellent smoke and toxic gases suppression in FPUF, the PSPR and TSR are reduced by 24.6% and 51.9%, and the COP and COY are also reduced by 51.9% and 55.3%, respectively. After adding the copper salt hybrid, the buffering performance of FPUF did not change. Fortunately, the tensile and compressive strength increase obviously. The flame retardant and smoke suppression mechanism of hybrid FPUF has also been studied. This article gives a effective strategy for the preparation of FPUF with outstanding mechanical property, flame retardant and smoke suppression properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three kinds of flame retardant with different phosphorus content were synthesized. • MPBT exerted the best synergistic flame retardant effect. • The dual-phase flame retardant mechanism was analyzed in detail. • Tensile strength of flexible polyurethane foam was improved to a large extent. Herein, three different phosphorus-containing compounds (methyl phosphoryl dichloride, phenyl phosphoryl dichloride and phenyl dichlorophosphate) were reacted with 2-aminobenzothiazole respectively, and a series of synergistic flame retardants with phosphorus, nitrogen and sulfur elements were synthesized, named MPBT, PPBT and POBT respectively. Then, they were added to prepare flame-retardant flexible polyurethane foam (FPUF). Through the analysis of thermal stability, pyrolysis, heat release and smoke release behavior, the influence of different phosphorus-containing structures on the flame-retardant performance of FPUF was studied, and their flame-retardant mechanism was explored in detail. Among them, MPBT had the highest flame retardant efficiency with the same addition amount (10 wt%). The limiting oxygen index (LOI) value of PU/10.0% MPBT reached 22.5 %, and it successfully passed the vertical burning test. Subsequently, the addition amount of MPBT was increased and the best comprehensive performance of flame-retardant FPUF was explored. The results showed that the LOI value of PU/15.0% MPBT was increased to 23.5%. As for PU/15.0% MPBT, the peak heat release rate (PHRR) was 453 KW/m2, which was reduced by 46.64 %; and the flame retardancy index (FRI) value was also increased to 6.88. At the same time, the mechanical properties of flame-retardant FPUF were studied. The tensile strength of PU/15.0% MPBT reached 170 KPa, and the permanent deformation of FPUF/10% MPBT was only 4 %, showing its excellent resilience. The above results show that this phosphorus-containing element hybrid synergistic flame retardant (MPBT) has a very good application prospect in the field of flame-retardant polymer materials. [ABSTRACT FROM AUTHOR]

A SiO 2 based polymeric composite coating is developed via a facile strategy to get fire resistance for wooden materials. The composite coatings exhibit strong interfacial adhesion to versatile flammable substrates. The coating-treated wood features well flame resistance, a high LOI of 48.0%, a desired V-0 rating during vertical burning, low heat release rate and long ignition time. [Display omitted] Fire resistant coatings have been proven as an efficient way to improve fire safety in three aspects: reducing the Heat Release Rate (HRR), delaying the ignition time and preventing heat transfer. Herein, a SiO 2 based polymeric composite coating with a lower thermal conductivity and brilliant fire resistance was developed. Isocyanate and sodium silicate could form the final Si-O-Si network structure by polymerization. Compared to the wood without coating, the coated wood shows a significantly increase in limit oxygen index (LOI), has reached 48.0 vol% in the test. As for the cone calorimetry test, coated wood shows a 55.3% decrease in the first peak Heat Release Rate (pHRR) and the Total Heat Release (THR) obtains fire-resistant standard. After exposed to butane flame for 30 mins, the coated wood could still maintain its structural integrity with only 180℃ on the non-exposed side. The commercial standard test of the coating was also investigated. To better understand what role does the polyurea play in the system, a theoretical calculation was done during the research to discuss the interaction between the silica and polyurea. As a fast brush-formed coating, it exhibits a great potential in the field of fire-resistant materials, and may broaden the application prospects of wood. [ABSTRACT FROM AUTHOR]

Considerable toxic gases and high temperature smoke will be generated during the combustion of polystyrene (PS), which restricts its application. Here, a cobalt-based MOF-71-NH 2 (hereinafter referred to as MOF-NH 2) has been synthesized and further modified with phosphonitrilic chloride trimer (PCT) by a post-synthesis modification (PSM) strategy, named as PCT@MOF-NH 2 , which was used to enhance the flame retardancy of PS. Desirable results were obtained as expected: the fire safety and tensile strength of PS were prominently improved after adding PCT@MOF-NH 2. Compared with pure PS, there were more than 40% and 31% decreases in the value of pHRR and THR with 3.0 wt% content of PCT@MOF-NH 2. From the analysis of gaseous and condensed products after combustion, the possible flame retardancy mechanism of PS nanocomposites can be attributed to the barrier effect of PCT@MOF-NH 2 , which provides a promising application field of MOFs to improve flame retardation of polymer materials. [ABSTRACT FROM AUTHOR]

• A simple sol-gel method is employed to modify the surface of ZrP nanosheets. • EP/IFR/OZrP composite successfully pass UL94 V0 rating and obtain LOI of 44. • The impact strength of EP/IFR/OZrP composite is effectively improved. Even though the incorporation of zirconium phosphate (ZrP) nanosheets can enhance fire safety of epoxy (EP) resin, the sole addition of ZrP nanosheets cannot make EP resin pass the UL94 V0 rating and obtain high limit oxygen index (LOI). Meanwhile, traditional intumescent flame retardants (IFR) also deteriorate the mechanical properties of EP/ZrP composites. Herein, for optimizing fire safety and mechanical property, organically modified ZrP (OZrP) nanosheets are prepared based on simple sol-gel chemistry and further combined with IFR to enhance the overall performance of EP composite. Compared to LOI values of pure EP (25) and EP/IFR composite (38), incorporating 2.0 wt% OZrP nanosheets further increase LOI to 44. Meanwhile, EP/IFR/2.0 wt% OZrP composite successfully pass the UL94 V0 rating at the thickness of 0.8, 1.6, and 3.2 mm. As expected, the deterioration of mechanical performance of epoxy resin caused by the addition of IFR is obviously suppressed by introducing OZrP nanosheets, confirmed by impact strength of up to 12.7 kJ/m2 of EP/IFR/3.0 wt% OZrP composite. In the cone calorimeter test, the combination of 2.0 wt% OZrP and 20.0 wt% IFR significantly decreases the peak value of heat release rate and total heat release of EP resin by 83.9 % and 59.7 %. According to the microstructure and chemical composition of char residue, an intumescent and graphitized char formation mechanism is raised for the significantly enhanced fire safety in EP/OZrP/IFR composites. The optimization effect of OZrP nanosheets in the fire safety and mechanical property of epoxy/intumescent flame retardant composites further promote the practical application of epoxy resin. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A hierarchical MoS 2 @TiO 2 structure is firstly designed and synthesized. • The combination properties of BD with 2 wt% MoS 2 @TiO 2 loading is greatly enhanced. • The mechanism of MoS 2 @TiO 2 in enhancing combination properties of BD is proposed. Abstract Bismaleimide/diallyl bisphenol A (BD), a kind of allyl-modified bismaleimide (BMI) system, which is widely used in the fields of aviation, aerospace, machinery, and electronics. However, the further applications of BD are severely restricted by its high crosslink density, brittleness, and undesirable flammability. In order to overcome these drawbacks, a hierarchical MoS 2 @TiO 2 structure is designed and synthesized to improve the mechanical and fire safety of BD, which are well matched with the high curing temperature and application temperature of BD. Specifically, with a relatively low loading of 2 wt% MoS 2 @TiO 2 , then the peak heat release rate (pHRR) and total heat release (THR) of BD composites are 314.25 kW/m2 and 53.58 MJ/m2, respectively, which are decreased by 32.5% and 15.0% in comparison to those of the pristine BD. Meanwhile, the TSR and yields of poisonous gases, especially CO and nitric oxide of BD/MoS 2 @TiO 2 2.0 are greatly decreased which indicates that the fire safety is effectively enhanced. The impact strength of BD/MoS 2 @TiO 2 2.0 sample is increased to 12.44 kJ/m2, which corresponding to a 96.8% compared with that of pure BD, and its storage modulus is 44462 MPa, a little higher than that of pure BD. Furthermore, Tg of BD/MoS 2 @TiO 2 2.0 is increased to 326 °C with a lower cross-linking density while that of BD is 316 °C. Conclusively, this investigation demonstrates that the MoS 2 @TiO 2 is a significant nano-additive for developing high-performance BD resins with excellent fire safety and mechanical properties, which provides a novel strategy for designing advanced BD composite material. [ABSTRACT FROM AUTHOR]

A novel charring agent (PEPAPC) containing pentaerythritol and triazine structure, was successfully prepared via the nucleophilic substitution reaction of cyanuric chloride, 2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-4-methanol (PEPA), and piperazine. Then, different proportions of PEPAPC and ammonium polyphosphate (APP) were added into polypropylene (PP) at a 20% total loading via melt blending. The results of limiting oxygen index (LOI), vertical burning test (UL-94), thermogravimetric analysis (TGA) and cone calorimeter test revealed that PEPAPC/APP system could effectively enhance the thermal stability and flame retardance of PP. When the weight ratio of APP to PEPAPC was 3:1 with a 20% loading (PP6), the PP composite achieved the highest LOI value of 28% and passed the vertical burning test (UL-94) V-0 rating. Meanwhile, PP6 showed the highest amount of char residues via TGA test and the lowest PHRR (253 kW/m 2 ) via cone calorimeter test. Moreover, Scanning electron microscopy (SEM) also indicated that PEPAPC/APP system benefited to the formation of more compact char layer which hindered the transfer of volatiles and heat during burning. The investigation of their water resistance demonstrated that the PP6 still obtained a UL-94 V-0 rating after 72 h dipping in hot water. [ABSTRACT FROM AUTHOR]

Bio-based and phosphorus-free coating was fabricated by layer-by-layer assembly method to obtain the flame retardant cotton fabric. For the first time, the modified cotton fabrics were prepared by utilizing positively charged polyethylenimine and negatively charged alginate together with subsequent crosslinking of barium, nickel and cobalt ions. Scanning electron microscopy and energy-dispersive X-ray demonstrated that the metal ions crosslinked coating was successfully constructed on the substrate. The thermal stability and flame retardancy were investigated by thermogravimetric analysis (TGA) and horizontal flame tests. TGA results showed that the degradation of the coated cotton fabrics were retarded at high temperature and the char residue of the cotton fabrics were improved after covered with the barium, nickel and cobalt ions crosslinked coatings. Furthermore, the fire resistance of cotton-Ba sample was enhanced significantly compared with the untreated sample, as evidenced by the obvious reduction (28%) of flame spread rate and complete char residue. Finally, the washing durability of coating on the fabric was enhanced after metal ions crosslinked with alginate based coating. [ABSTRACT FROM AUTHOR]

Carbon derived from peanut shell (CPS) with 2D structure has been proved to own sufficient thermal stability and is a promising flame retardant (FR) additive for EP in our previous work. To further explore the feasibility of implementing CPS into the intumescent fire retardant (IFR) system, a novel green IFR system was first proposed in this study. Environmental-friendly chemicals phytic acid (PA) and melamine were self-assembled on the carbon's surface through the hydrothermal method. Cone calorimeter test results reveal that 3 wt% loading of the proposed IFR reduces total heat release (THR) by 38.8 % and total smoke release (TSR) by 31.3 %. What's more, the char residue grows significantly, from 5.8 % to 14.3 %. The fire retardancy mechanism was also studied. For the gaseous phase, the release of inert gas products from melamine prevents volatile decomposition products into the combustion zone. In terms of the solid phase, a synergistic barrier effect is provided by 2D structure of peanut shell derived carbon and the intumescent residue with a compact exterior layer, protecting the underlying polymer matrix. This green IFR system provides better fire performance, which can be a potential alternative for EP and extend its application. • A novel bio-inspired IFR system was firstly constructed. • Phytic acid and melamine were successfully self-assembled on peanut shell derived carbon. • 3 wt% loading of the proposed IFR reduced THR and TSP by 38.8 % and 31.3 %, respectively. • The synergistic physical barrier effect was provided by 2D structure carbon and the intumescent effect for char formation. [ABSTRACT FROM AUTHOR]

A novel phosphorus/nitrogen-containing hyperbranched polymer (PN-HBP) was synthesized via esterification reaction of 2-carboxyethyl (phenyl) phosphinic acid (CEPPA) and tris (2-hydrooxyethyl) isocyanurate (THEIC). PN-HBP was characterized by Fourier transform infrared (FTIR) spectrometry and 1 H nuclear magnetic resonance ( 1 H NMR) spectrometry. Its initial decomposition temperature (T −5wt% ) is around 300 °C as the thermogravimetric analysis (TGA) showed. The flame-retardant polypropylene (PP) composites were prepared with the combination of PN-HBP and ammonium polyphosphate (APP) via melt blending. A higher limiting oxygen index (LOI) and a V-0 rating in the UL-94 vertical burning test were realized, indicating an apparent synergistic effect. The peak heat release rates (PHRR) of composites were reduced significantly compared with that of PP. The structure of the char residue was tested by Raman spectroscopy, indicating that the combination of PN-HBP and APP can prompt the formation of graphitized carbon layers and therefore improves the flame-retardancy of the PP composite. [ABSTRACT FROM AUTHOR]

In this research, a novel triazine-based polymeric flame retardant (TBMC) was synthesized. The intumescent flame retardant (IFR) system was formed by combining. TBMC with ammonium polyphosphate (APP), and is applied to retard the combustion of polypropylene (PP). PP/IFR samples (APP/TBMC = 3/1 to 1/1) achieved increased limited oxygen index (LOI) values and passed the vertical burning (UL-94) V-0 rating. Herein, cone calorimeter tests show that the heat release rate (HRR) and fire growth index (FGI) of PP/APP/TBMC blends were obviously decreased compared to those of pure PP and PP with 25 wt% APP. The thermogravimetric analytical (TGA) results showed that the TBMC/APP system could improve the thermal and thermal-oxidative stability of the char residues. The char residues were further investigated by visual observation and scanning electron microscopy (SEM). The compact char residues formed hindered the transfer of gas and heat during combustion, ultimately endowed PP/IFR systems improved flame retardancy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Utilizing the flame retardancy advantages of polyphosphazene and melamine, PPM was firstly designed and synthesized. • PPM has a positive effect on enhancing the fire safety and mechanical properties of BMI. • PPM is an integrated intumescent flame retardant and the cooperation effect of polyphosphazene and melamine in PPM is revealed. In view of the problems of poor toughness and high fire risk of bismaleimide (BMI), a novel maleimide-functionalized triazine-rich polyphosphazene microsphere (PPM) was designed and prepared in this work by combining the flame retardant advantages of polyphosphazene and melamine. The functionalization of organic maleimide in PPM can improve the interfacial compatibility between PPM and BMI. With addition of 2.0 wt% PPM, the peak value of heat release rate (PHRR) and total smoke production (TSP) of BMI/PPM-2.0 decrease by 52.8 % and 30.8 %, respectively, while its impact strength increases by 97.5 %, which means that the fire safety and toughness of BMI/PPM are much better. The study on flame retardant mechanism of PPM reveals that PPM has obvious condensed-phase intumescent flame-retardant effect, which may be due to the similar composition of PPM and intumescent flame retardant. In addition, PPM has the phosphorus-oxygen radical flame-retardant effect in gas phase and also has the toughening effect of inorganic rigid particles on BMI performance. [ABSTRACT FROM AUTHOR]

Devoting to coping with safety risk spreading with polymers, this work achieves dramatic synergistic improvements in composite toughness, photothermal healing, and fire safety through a novel targeted modification strategy for black phosphorus (BP). In detail, we herein use the emerging 2D BP as a template for in-situ growth by covalent triazine framework (HBP-CTF). Incorporating gradient increased HBP-CTF (1, 2, 4 wt%) into polystyrene (PS), the elongation at break increased by 61.59%, 74.60% and 62.82% for composites, respectively. This is attributed to the synergistic effects of two components of HBP-CTF as stress conduction unit and interface and dispersion improver, respectively. Furthermore, PS/HBP-CTF composites achieve photothermal healing over 96% in strength and elongation at break induced by outstanding photothermal properties (linearly quantifiable, R2 > 0.997). Noted, PS/HBP-CTF 2.0 and PS/HBP-CTF 4.0 achieve record reductions of 61.77% and 69.85% in peak heat release rate, accompanied by dramatically reduced total heat release. Taking the pyrolysis of HBP-CTF as an index, this work proposes the idea of using P 4 as the key product to monitor and distribute gas phase effects for BP-based flame retardants. The hybridization of CTF to HBP promotes the slow and continuous release of P 4 in the gas phase, revealing the structure and composition of char that cross-linking P and N. This work provides strategies for synergistically overcoming composite brittleness, crack failure, and high flammability, paving the way for practical applications. [ABSTRACT FROM AUTHOR]

A series of graphitic carbon nitride (g-C 3 N 4 ) wrapped ammonium polyphosphate (APP) (CNAPP) were firstly prepared, and then incorporated into polystyrene (PS). The results indicated the successful wrapping of APP by g-C 3 N 4 . The CNAPP exhibited the higher thermal stability than pure APP. Enhanced interfacial interactions between CNAPP and PS were obtained upon introduction of CNAPP. The thermal stability of PS/CNAPP composites was significantly improved, compared with that of PS containing an equal amount of APP. Moreover, cone results showed that the heat release rate and total heat release were reduced greatly for PS/CNAPP20. It was confirmed that the formation of P O C and P N C structures could remarkably improve the stability of char layer and thus result in the better flame retardancy of CNAPP, besides the enhanced thermal stability. The work provides a new paradigm for potential application of APP in polymeric materials. [ABSTRACT FROM AUTHOR]

Aiming to address the problems of flammability and brittleness of BMI and reduce the use of petroleum-based materials, three kinds of cardanol-based co-curing agents (CDPO, CDPC, CDCP) were synthesized and applied to prepare advanced BMI. Compared to the neat BMI, the modified BMI exhibited better thermal stability with higher decomposition temperatures and char yields. The BMI/CDCP-10 containing 4.5 wt% CDCP possessed the best flame retardancy with 50.4% reduction in PHRR, 27.5% reduction in THR and 21.2% reduction in TSP compared to those of neat BMI. Moreover, with the 4.5 wt% incorporation of CDPO, CDPC and CDCP, the impact strength of BMI was enhanced by 95%, 133.8% and 127.5% respectively, due to the flexible fatty chains and the decreased crosslinking density. The reason for different modification effects among modified BMI systems is studied from the structure of modifiers, finding that the phosphorylated cardanol with higher content of O and higher valence of P can be utilized to improve the mechanical property and fire safety of BMI. This work provides a new way to reduce the dependence on the petroleum-based materials and expand the application areas of BMI. [Display omitted] • Three cardanol-based co-curing agents (CDPO, CDPC, CDCP) with different phosphorous structure were synthesized. • The PHRR, THR and TSP of BMI with 4.5 wt% CDCP can be declined by 50.4%, 27.5% and 21.2%, respectively. • The impact strength of BMI was maximally increased by 133.8% with the 4.5 wt% CDPC. • The thermal stability, flame retardancy and mechanical performance of BMI were greatly elevated by the modifiers. [ABSTRACT FROM AUTHOR]

A novel carbon fiber/MXene coalition (CF-Ar-MXene) is synthesized via a bidirectional aryl diazonium chemistry method using p-phenylenediamine as a chemical bridge, which effectively combines the two materials with different dimensions and makes full use of the advantages of both. CF-Ar-MXene coalition materials achieve high surface roughness and rich oxygen-containing active groups due to the presence of MXene on the surface of CF, which leads to the favorable interfacial interaction and compatibility between CF-Ar-MXene and epoxy resin (EP) matrix. As expected, after the incorporation of CF-Ar-MXene coalition into EP matrix, the flame retardancy and mechanical properties of EP composites are significantly improved. For example, with the addition of 3 wt% CF-Ar-MXene coalition, the peak heat release rate (PHRR), total heat release (THR) and total smoke production (TSP) of EP composites decrease by 42.6%, 48.2% and 32.1%, respectively. Meanwhile, the TG-IR results indicate that the amount of combustible volatile products and toxic gases also significantly decrease. Notably, with 2 wt% loading of CF-Ar-MXene coalition in EP composites, the tensile strength and elongation at break increase by 49.9% and 40.5%, respectively. Therefore, the efficient cooperation between CF and MXene in CF-Ar-MXene coalition and excellent interface compatibility with EP matrix are the main reasons for the excellent flame retardancy and mechanical properties of EP/CF-Ar-MXene composites. [Display omitted] • CF-Ar-MXene coalitions were prepared by a bidirectional aryl diazonium chemistry method for the first time. • The method used in this experiment is efficient and eco-friendly compared with the traditional modification method for CF. • CF-Ar-MXene coalitions achieved high filler efficiency in reducing the fire hazards and smoke production of EP. • Mechanical properties of EP/CF-Ar-MXene composites were efficiency enhanced. [ABSTRACT FROM AUTHOR]

The weak anti-oxidation and smoke-suppression abilities limit the use of black phosphorus (BP) in the preparation of high-performance flame-retardant epoxy resin (EP) composites. Here, aromatic diazonium chemistry was used to graft phenylboronic acid on the surface of few-layer BP nanosheets (BPNSs) to obtain passivated BP-based nanomaterials (BP-DPBA). Then, a novel multifunctional nano flame retardant BP-DPBA@Co-BO was obtained by anchoring amorphous cobalt-based borate (Co-BO) on the surface of BP-DPBA through a low-temperature reduction reaction. Subsequently, BP-DPBA@Co-BO was incorporated into EP matrix in the form of nanofillers and formed a mechanically enhanced system. As expected, EP nanocomposites containing 2 wt% BP-DPBA@Co-BO achieves greatly improvements in thermal stability and fire safety, with 93% increase in char yield (CY) during pyrolysis, 48.4% and 41.7% decrease in peak heat release rate (PHRR) and total heat release (THR) during combustion respectively, a limiting oxygen index (LOI) value up to 32.5% and a UL94 rating of V0. In addition, the presence of Co-BO greatly improves the ability of BP to suppress toxic smoke. Specifically, EP/BP-DPBA@Co-BO 2.0 achieves a 25.4% reduction in total smoke production (TSP) during combustion. In particular, the maximum 36.2% and 73.2% increases are achieved in storage modulus and impact strength, respectively, confirming that BP-DPBA@Co-BO can effectively enhance the mechanical properties of EP. Therefore, this work provides a feasible solution for loading high-valence metal compounds on the surface of BPNSs, and prepared high-performance EP nanocomposites with enhanced fire safety and mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

With the advent of the 5G era, preparing conductive polymers to accomplish electromagnetic interference (EMI) shielding, mechanical enhancement, and flame retardancy are of vital importance. Graphite felt (GF) acts as a three-dimensional structure and organophosphorus derivatives containing different valences work as a flame retardant to form a novel EP composite. With GF incorporated into EP, EMI shielding effectiveness (SE) achieves around 60 dB, and absorption is dominated in the X band (8.2–12.4 GHz). Meanwhile, GF could exert a fiber reinforcement effect to enhance the mechanical properties of EP composites, tensile strength and impact strength of EP/GF are increased by 19.1% and 64.2%, respectively. However, owing to the "wick effect" of GF, 20 wt% DOPO-PEPA is added to acquire flame-retardant EP composites. Herein, a potential strategy broadens applications of EP composites in the high-end field and is provided to prepare polymer composites. [Display omitted] • A cost-reasonable EP composites composed of 3D GF and two-valence phosphorous derivatives is successfully fabricated. • The EMI SE EP composites achieve around 60 dB in the X band. • The pHRR and THR of EP/GF/20FR are reduced by 53.4% and 35.3%, respectively. • EP composites exhibit potential promise for large-scale production and industrial applications. [ABSTRACT FROM AUTHOR]

A novel hyperbranched charring foaming agent (HCFA), successfully prepared via an A 2 B 3 approach with about 97% yield, was combined with ammonium polyphosphate (APP) to flame-retard polypropylene (PP) at a 30 wt% loading. The results of thermogravimetric analyses of various PP samples in air and nitrogen showed that the HCFA/APP system could effectively improve the thermal and thermal-oxidative stabilities of the char residues. And PP3 with a 3/1 mass ratio of APP to HCFA left the highest amount of char residue at 800 °C. The studies of their flammability revealed that the addition of HCFA can make great contribution to the increase of the limiting oxygen index and the UL-94 V0 rating, and the decrease of the heat release rate (HRR) and fire growth index (FGI) of PP/APP/HCFA composites relative to PP with 30 wt% APP. The investigation of their water resistance demonstrated that the PP composites with a mass ratio of APP to HCFA being between 3:1 and 1:1 still obtained a UL-94 V-0 rating after 168 h soaking in hot water, due to the delayed migration of intumescent flame retardant from the complexation between hydrophilic APP and hydrophobic HCFA. Besides, their mechanical properties were also investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • BP-Ti 3 C 2 nanohybrids were obtained by two-electrode electrochemical exfoliation method. • The smoke release of WPU/BP nanocomposites during combustion was suppressed with the introduction of Ti 3 C 2. • The mechanical properties and fire safety of WPU were simultaneously improved. The low exfoliation yield and large solvents consumption have become the major issue that limits the commercial application of two-dimensional nanomaterials. Emerging as an effective and environmentally friendly approach, electrochemical exfoliation has been attached by extensive concern. Hence, a simple and environmentally friendly two-electrode electrochemical exfoliation method was put forward to prepare black phosphorus-MXene (BP-Ti 3 C 2) nanohybrids without consumption of any organic solvents. The integration of BP and Ti 3 C 2 also imparts higher fire safety and mechanical properties to waterborne polyurethane (WPU). With the incorporation of 2.0 wt% BP-Ti 3 C 2 , the peak heat release rate, total heat release, total smoke production and total CO 2 yield of WPU were decreased by 42.2%, 12.9%, 12.6% and 16.5%, respectively, exhibiting a great flame retardancy effect. The employment of electrochemical exfoliation method towards BP and Ti 3 C 2 nanosheets not only imparts higher fire safety to polymer composites, but also provides a referable environmentally friendly preparation for two-dimensional nanomaterials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel phosphine oxide-containing hyperbranched polyol was synthesized. • RPUF containing POCHP and EG exhibit excellent fire safety and physical properties. • The production of CO and NO x during combustion of RPUF are significantly decreased by combination of POCHP and EG. In this work, a novel phosphine oxide-containing hyperbranched polyol (POCHP) was synthesized. Then POCHP and/or expandable graphite (EG) were incorporated into rigid polyurethane foam (RPUF). EG increases foam density and deteriorates compressive strength and thermal conductivity, but POCHP has opposite effects. A 12.8% improvement of compressive strength and slightly decreased density and thermal conductivity are achieved by ERPUF50 containing POCHP and EG. And it reaches a limited oxygen index of 30.0% and UL-94 V-0 rating with immediate self-extinguishing behavior after removing flame. The peak heat release rate, total heat release and total smoke production of ERPUF50 are reduced by 71.1%, 52.2% and 71.1% respectively via bi-phase flame retardant mechanisms. Interesting phenomena were observed that POCHP promotes the intumescence of EG after combustion. The results of combustion gas analysis reveal that single POCHP or EG reduces the production of CO but increases the generation of NO x. ERPUF50 exhibits a 52% decrement of CO and an unexpected 40% diminishment of NO x. ERPUF50 with excellent comprehensive properties can not only be used as fire safe thermal insulation material with high physical performances, but also significantly reduce the release of contaminative smoke, CO and NO x in fires and waste RPUF disposal by combustion. [ABSTRACT FROM AUTHOR]

• Hydrophobic hierarchical OH-BN@CuCoOx was innovatively prepared by the MOF-derived strategy. • OH-BN@CuCoOx achieved high filler efficiency in reducing THR and TSP of BMI. • BMI/OH-BN@CuCoOx 0.5 achieved an 80 % increase in impact strength. • BMI/OH-BN@CuCoOx 0.5 achieved a 49 °C increase in Tg. In this work, the MOF-derived strategy was used to generate copper-cobalt metal oxide (CuCoOx) in situ on the surface of hydroxylated boron nitride (HO-BN), and a new type of nano-hybrid (HO-BN@CuCoOx) was obtained. Then, HO-BN@CuCoOx was dispersed in the bismaleimide resin (BMI) matrix in the form of a layered structure, forming a strong interface interaction. The results of the cone calorimeter test exhibited that the fire hazard and toxic smoke release of BMI nanocomposites containing 2 wt% HO-BN@CuCoOx were effectively suppressed, such as a 37.2% reduction in total heat release rate (THR), a 38.5% reduction at peak heat release rate (PHRR), 24.3% decrease in total smoke production (TSP) and 62.2% decrease in peaks of carbon monoxide (CO) production rate. Compared with previous studies, higher filling efficiency was achieved. In addition, BMI/HO-BN@CuCoOx 0.5 achieved an 80% increase in impact strength, revealing excellent toughness. In particular, the glass transition temperature (Tg) of BMI/HO-BN@CuCoOx 0.5 reached 330 °C, an increase of 49 °C compared to the pure sample, which increased the potential for application in extreme environments. Therefore, the developed new BMI/HO-BN@CuCoOx nanocomposites expanded the application potential of BMI in the high-end field. [ABSTRACT FROM AUTHOR]