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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]

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]

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]

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]

• 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]

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]

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]

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]

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]

• 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]

[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]

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]

• An organic-inorganic hybrid flame retardant (THPSU-MMT) was synthesized. • EP-MMT composites have good flame retardancy and comprehensive properties. • The thermal decomposition of EP-MMT composites was studied. • It provides a green and efficient method for exfoliation of montmorillonite. Traditional additive flame retardants pose issues including high dosage, easy precipitation, and poor compatibility with the matrix. Designing efficient organic-inorganic synergistic flame retardants can enhance the flame retardancy and mechanical properties of epoxy (EP) composites while reducing their smoke toxicity. In our study, we initially employed Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) for intercalation modification of montmorillonite (MMT). Subsequently, we achieved a green and efficient exfoliation of MMT by reacting urea with hydroxyl groups, resulting in the simultaneous preparation of efficient organic/inorganic synergistic flame retardants (THPSU-MMT). EP composites containing 5wt% THPSU-MMT can attain UL-94 V0 classification. Furthermore, the peak heat release rate (PHRR), total heat release (THR), and peak release rates of CO can be reduced by up to 78.42 %, 62.26 %, and 72.50 %, respectively. Simultaneously, we systematically investigated the synergistic flame retardant mechanism of the EP composite. The findings reveal that THPSU-MMT exhibits a dual flame retardant effect in both the gaseous and condensed phases. Moreover, the combination of MMT and THPSU substantially enhances the presence of phosphorus-containing pyrolysis products in the condensed phase. The fire performance index (FPI) of the flame retardant EP increased from 0.05 m2/s/W in pure EP to 0.36 m2/s/W, attributed to the enhanced catalytic carbonization and assisted gas-phase free radical capture. Additionally, the flame spread index (FGI) decreased from 11.55 kW/m/s in pure EP to 1.18 kW/m/s, signifying a substantial enhancement in fire safety. Furthermore, the THPSU-MMT synergistic flame retardants improved the tensile strength of EP composites. This study offers an environmentally friendly and efficient approach for the effective exfoliation of MMT, while also presenting novel concepts for the design of efficient organic-inorganic synergistic flame retardants. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] It's known that the application of bismaleimide resins (BMI) is limited due to its brittleness and poor flame retardancy. A novel type of BMI monomer (MADQ) based on the typical phosphorus series flame retardant DOPO is designed to improve the fire safety of BMI. Besides, aliphatic long chain structure is introduced in MADQ, which is supposed to be conducive to reducing the rigidity of the BMI cross-linked network and thus to improve the toughness of BMI. It's seen that with the incorporation of 5.24 wt% MADQ, the peak of heat release rate (PHRR) and total heat release (THR) of resultant BMI/MADQ-5 is reduced by 37.7% and 33.9%, respectively. Meanwhile, with modification of 1.07 wt% MADQ, BMI/MADQ-1 possesses UL-94V-0 rating. The relevant mechanism analysis reveals that the phosphaphenanthrene group in MADQ can exert flame retardancy effect both in condensed and gas phase. Besides, the impact strength of the BMI/MADQ is maximally increased by nearly 90.1%. Furthermore, the BMI/MADQ still maintains high tensile strength and thermal stability, which indicates the modification of MADQ did not deteriorate other properties of BMI. An innovative research idea and research basis for the preparation of intrinsic flame-retardant and toughened BMI is provided in this work. [ABSTRACT FROM AUTHOR]

[Display omitted] Polyolefin (PO) cables used in confined spaces need to have low smoke, low heat release, low toxic gas release and excellent physical properties. In this work, a series of rare earth stannates Re 2 Sn 2 O 7 (RES, Re = Nd, Sm, Gd) with high temperature catalytic performance were prepared by hydrothermal method for synergistic flame retardant PO/IFR. The flame retardancy, heat release, smoke density, toxic gas release and physical properties of PO composites were thoroughly studied in detail. The RES could enhance the vertical burning rating and the limiting oxygen index (LOI) of PO/IFR composites. Moreover, the residual char of the thermogravimetric analysis increased from 9.7% to 11.4 wt% after the RES added in PO/IFR system. Interestingly, the PO/IFR system containing Gd 2 Sn 2 O 7 exhibits the lowest peak heat release rate of 233.7 kW/m2. Excellent flame resistance due to the formation of a complete and compact protective char layer. In addition, the toxic release of PO during combustion is also effectively reduced by introducing the RES. The tube furnace combustion test shows that the emission of carbon oxide (CO) and hydrogen cyanide (HCN) of PO/IFR/Gd 2 Sn 2 O 7 are the lowest. It can be attributed to the catalytic effect of rare earth elements and the blocking effect of the dense char layer. In addition, compared with the PO/IFR composites, the PO/IFR/RES system demonstrate higher mechanical properties and volume resistivity. Therefore, the addition of RES has a positive effect on improving the physical properties and fire safety properties of the PO/IFR cable composites, especially suitable for using in confined spaces. [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] As an antioxidant, hindered phenol scavenges free radicals. Due to the oxidative degradation of black phosphorus (BP) in the presence of water and oxygen, free radical quenching of hindered phenol antioxidants can solve this issue and improve the environmental stability and flame retardant efficiency of BP. Herein, hydroxyl-modified BP (BP-OH) with active groups on the surface was obtained by hydroxylation, and then the hindered phenol antioxidant was grafted onto the surface of BP-OH through an isophorone diisocyanate bridging covalent reaction to obtain hindered phenol-modified BP (BP-HPL). The fire hazard of thermoplastic polyurethane (TPU) can be significantly reduced by introducing BP-HPL into TPU. Adding 2 wt% BP-HPL can reduce the heat release rate and total heat release values of TPU by 49.9% and 49.0%, respectively. In addition, the reductions in smoke volume and carbon monoxide production were also significant. Compared with BP-OH, the environmental stability of BP-HPL is significantly improved. This work provides a reference for the application of BP in the field of fire safety and simultaneously achieves the improvement of the environmental stability and flame retardant performance of BP. [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]

[Display omitted] A sandwich-like melamine/phytic acid/silicon nitride hybrid (SW-Si 3 N 4) sheets were prepared by supramolecular wrapping as the hybrid flame retardants for thermoplastic polyurethane (TPU). The introduction of Si 3 N 4 sheets as a template could not only induce the generation of two-dimensional phytic/melamine (PAMA) capping layers, but also produce the synergistic flame-retardant effect on TPU composites. Cone test showed that heat release rate (HRR), smoke production rate (SPR) and total smoke production (TSP) values of TPU were decreased obviously by adding SW-Si 3 N 4. TG-IR test indicated the dramatic inhibition of aromatic compound, hydrocarbons, CO and HCN release. Besides, the thermal conductivity of composites was obviously improved by adding SW-Si 3 N 4. This work may provide better reference for developing multi-functional TPU composites for diverse application. [ABSTRACT FROM AUTHOR]

The demand for "green" materials increases due to concerns about the effects of flame-retardant textiles. Using natural plant-base compounds such as phytic acid (PA) and the most abundant green amino polysaccharide chitosan (CS) as effective and durable flame retardants for textiles is essential for creating sustainable and ecological textile products. This study aims to develop a novel, eco-friendly, phosphorus- and nitrogen-containing flame retardant known as ammonium phytate (AP), intending to improve the flame retardant properties of polyamide 6.6 (PA6.6) textiles. UV-induced grafting with 2-acrylamide-2-methylpropane sulfonic acid (AMPS) increases the surface functional groups of PA6.6 fabrics. Later, the surface-modified fabrics were coated with phosphorus-containing heteroatom-based components, namely, sulfur, nitrogen, silicon, and boron, onto a single flame retardant system via layer-by-layer (LBL) deposition of positively charged chitosan/boron drop (3-aminopropyl) triethoxysilane/silicon dioxide (CS/BAPTES/SiO 2) sole solution and negatively charged AP solution to enhance superior hydrophilic and durable flame retardant performance. According to the data, a weight pick-up of 56.5% is attributable to only 4 BLs. However, all the flame-retardant-coated fabrics can completely stop the melting-dripping tendency and achieve B-3 to B-2 ratings after the UL-94 vertical burning test. In addition, the LOI values of treated fabrics increase from 18.5% to 23.5% compared to a pure sample. The AMPS grafted with a 4BL-deposited fabric sample exhibits a maximum decrease in peak heat release rate (PHRR) of more than 54%. Moreover, the thermogravimetric analysis (TGA) test reveals a significant increase in thermal stability and char yield. Additionally, the as-prepared phosphorus-containing heteroatom-based coatings impart a water contact angle value of approximately 0⁰ within 2 s, demonstrating that the treated fabrics exhibit superior hydrophilic performance. Moreover, using AMPS-grafted and only 2-BL-deposited treatments improves coating stability in washing and imparts durable flame retardancy that can resist up to 20 washing cycles. It is proposed that the sustainable phosphorus-containing heteroatom-based coating may be a potentially effective replacement for existing durable flame retardants routinely used in textile finishing operations. [Display omitted] • UV-induced grafting of AMPS onto the PA6.6 fabric surfaces was done. • A P-containing heteroatom-based coating was applied successfully. • A maximum reduction in PHRR of over 54% was realized in only 4BL-deposited fabric samples. • An improvement in the superior hydrophilic fabric surfaces was attained. • Only 2 BLs of finishing treatment could stop the melt-dripping tendency even after 20 washing cycles. [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]

A plant derived bio-macromolecule namely lignin (L) and a green phosphorus compound like phytic acid (PA) were functionalized with graphene oxide (GO) and subsequently, used to enhance the flame retardant properties of polyamide 66 (PA66) fabrics in a one pot deposition method. Meanwhile, we also considered pure phytic acid and one more bio-derived charring agent like chitosan (CS) to formulate a series of GO-based flame retardant finishing by altering the applied compounds in the formulation. The applied finishing with a minimum loading % (i.e., less than 10%) rarely altered the physical properties (i.e., color, handle and tensile strength, etc.) of treated textiles while provided enhanced thermal stability and added flame retardancy. Thus, a significant increase in limiting oxygen index (LOI) by 27% was received for the GO-lignin and GO-phytic acid modified fabric sample (i.e., PA66-A), indicating the supremacy of graphene-based compound. Furthermore, a substantial reduction in the peak heat release rate (pHRR) by 25% was also noticed for the fabric sample treated with GO-lignin, chitosan and phytic acid (i.e., PA66-D). Additionally, the as prepared finishing exhibited a considerable level of wash durability as a maximum reduction of pHRR by 17% was retained even after 5 washing cycles. Unlabelled Image • GO-functionalized biomolecules were used in developing flame retardant PA66 fabric. • This treatment rarely altered the color, handle and tensile strength of PA66 fabric. • GO-lignin and GO-phytic acid treated PA66 fabric received a LOI of 27%. • PA66 treated with GO-lignin, chitosan and phytic acid showed 25% pHRR reduction. • These flame retardant and thermally stable coatings were wash-durable as well. [ABSTRACT FROM AUTHOR]

• Two different flame retardants named as DOPO-GPTMS and DOPO-APTES were synthesized. • Flame retardant compounds were applied to PA66 fabric surfaces via sol-gel method. • The as prepared coatings could able to stop the melt-dripping of PA66. • PA66 treated with 20 wt% DOPO-APTES showed a maximum 36% reduction in pHRR. • Incorporation of Si-compounds enhanced charring ability of DOPO. Two different DOPO- Alkoxysilane based flame retardant compounds were synthesized and applied onto the polyamide 66 (PA66) fabric surfaces via sol-gel method to improve the thermal stability and flame retardant properties. The as prepared coatings exhibited a much higher char yield% compared to the pure PA66 and simultaneously suppressed the dripping tendency of PA66 in the vertical burning test. The fabric sample modified with 20 wt% of DOPO-APTES showed a significant reduction in the peak heat release rate (pHRR) by 36%, whereas the 20 wt% of DOPO-GPTMS treated fabric sample could manage a 20% reduction in pHRR. The supremacy of DOPO-APTES treated fabrics were due to the co-presence of P, Si, and N elements; where a DOPO structure showed a quenching effect in a vapor phase, and Si-compounds accelerated the limited charring of DOPO in a condensed phase and stabilized the char residues in a higher temperature range. Moreover, the as treated PA66 fabrics show some sort of wash durability and among them, the fabric sample treated with 20 wt% of DOPO-APTES can withstand against fierce laundering where it maintains UL-94V-1 rating even after 10 washing cycles. [ABSTRACT FROM AUTHOR]

For improving the flame retardancy of epoxy resin (EP), β‐cyclodextrin@ ferrocene@hollow mesoporous silica microspheres (β‐CD@FE@HMS) were prepared successfully by the self‐assembly method. Then, they were used as flame retardant to improve the fire safety of EP. EP/β‐CD@FE and EP/HMS composites were also prepared for comparative study. The results showed that β‐CD@FE@HMS could effectively improve the thermal stability of EP, in which the initial degradation temperature and the amount of char residue of EP were increased. The content of small molecule toxic gases produced by the combustion of EP composite was also reduced apparently. With the addition of 5 wt% β‐CD@FE@HMS, LOI value of EP was increased to 27.5% from 19.8%, and UL‐94 reached V‐1 rating. Comparing with pure EP, the peak heat release rate and total heat release values of EP were reduced by 11.0% and 12.3%, respectively, and the total smoke production was reduced by 30.6%. EP/β‐CD@FE@HMS composite formed a higher quality char layer. Therefore, β‐CD@FE@HMS microspheres could improve the fire safety of EP. [ABSTRACT FROM AUTHOR]

Chitosan (CS) and phosphorylated chitosan (PCS) were deposited onto the polyamide 66 (PA66) fabric surfaces along with poly-acrylate sodium (PAS) via 'one pot' and layer by layer (LbL) assembly methods in preparing flame retardant coatings. Subsequently, to stabilize the deposited coatings, some of the fabric samples were treated under the UV-irradiation and additionally, a thermal treatment was also carried out for the remaining fabric samples. The LbL assembled fabrics showed a better homogeneity in the coating structure over the one pot deposited fabrics as appeared in scanning electron microscopy (SEM). Nonetheless, the LbL treated fabric sample (i.e., PA66-10BL-UV) with a higher weight gain% exhibited a greater improvement in limiting oxygen index (LOI) (i.e., 23%), and a reduced peak heat release rate (pHRR) (i.e., 25%). Yet more, only the LbL assembled and thermally cross-linked fabric sample could able to retain the flame retardant behavior in the vertical burning test even after 5 washing cycles. • A flame retardant coating for PA 66 textiles was developed from chitosan polymers • Coatings were constructed via one pot deposition and layer by layer assembly method • LbL assembled coatings exhibited a better homogeneity over one pot deposition • A maximal reduction of 25% in pHRR was achieved for LbL assembled fabric sample • LbL assembly showed superior flame retardancy over one pot deposited fabric samples [ABSTRACT FROM AUTHOR]

Simultaneous flame retardancy and tensile strength enhancement of poly(lactic acid) (PLA) is particularly important due to its eco-friendliness and potential application as an engineering plastic. This work investigates the application of azo-boron (AZOB) modified reduced graphene oxide (RGO) intercalated by sodium metaborate (SMB) for simultaneous flame retardant (FR), smoke/toxic fumes suppression and tensile strength enhancement of PLA nanocomposites. The RGO-AZOB/SMB hybrid was prepared by aryl grafting of AZOB on GO followed by in-situ reduction/intercalation with sodium borohydride/SMB. Then RGO-AZOB/SMB hybrid was incorporated into PLA, and the properties were examined. Cone calorimeter test demonstrates improved FR performance by substantial reductions in peak heat release rate ∼76.5%, total heat release ∼76.9%, total smoke release ∼55.6%, peak CO production ∼25.9% and peak CO 2 production by ∼78.6%. A V-0 rating was attained in the UL 94 test with a higher LOI value of 31.2%. Considerable reductions in pyrolysis products, mainly hydrocarbons, CO, CO 2 , and carbonyl compounds were observed. The tensile strength and Young's Modulus were improved by 49.1% and 34.9% respectively. The FR mechanism of RGO-AZOB/SMB/PLA nanocomposites is based primarily on the glassy charring effect of the B–OH groups in AZOB and the inherent lamellar blocking effect of RGO. Image 1 [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional additive (MCMH) is carefully designed. • The microencapsulation technology improves the compatibility between MCMH and XLEVA. • The OIT value of XLEVA/MCMH was basically unchanged after extracted for 5 days. • The retention of EB of XLEVA/MCMH could reach 71.8% after aging at 165 °C for 14 days. • The PHRR and Ds max of XLEVA/MCMH are reduced by 89.4% and 53.6%, respectively. A multifunctional additive is carefully designed for crosslinked ethylene–vinyl acetate copolymer (XLEVA) composites to improve their mechanical properties, aging resistance and fire safety. In this study, first, a layer of silica was microencapsulated on magnesium hydroxide to give a large amount of hydroxyl group on the magnesium hydroxide surface; second, the primary antioxidant 3-(3, 5-di- tert -butyl-4 hydroxyphenyl) propionicacid was grafted on SiMH surface to prepare antioxidant microencapsulated flame retardants (MCMH). Compared with the pure XLEVA, the peak heat release rate and the maximum smoke density of flame retardant XLEVA/MCMH are decreased by 89.46% and 53.6%, respectively. Moreover, these oxidation induction time values of XLEVA/MH/AO and XLEVA/SiMH/AO decreased sharply after extracted for 1d. However, the OIT value of XLEVA/MCMH was basically unchanged after extracted for 5d. After aging at 165 °C for 14 days and γ-ray irradiation dose of 500 kGy, the retention of elongation at break could reach 71.8% and 86.6%, showing excellent aging resistance. These results show that MCMH has a good synergistic effect for enhancing the flame retardant, mechanical property as well as aging resistance of XLEVA composites. The "Killing three birds with one stone" strategy provides an excellent solution for obtaining high-performance XLEVA cable materials. [ABSTRACT FROM AUTHOR]

Due to the inherent flammability of polypropylene (PP), it is limited in the application of flame retardant materials. In this work, a novel char forming agent, hyperbranched phosphorus-containing polyurethane (HPPU), was synthesized and used as efficient char forming agent. When ammonium polyphosphate (APP) was combined with HPPU, APP/HPPU endow PP significantly improved flame retardancy than single APP. Although the total carbon monoxide production (TCOP) of some PP/APP/HPPU composites is higher than that of PP/APP composite, it is still lower than that of neat PP. LOI (limited oxygen index) and UL-94 tests reveal that PP composites with 25 wt% HPPU/APP with ratio of 4:1 are able to reach 27 vol% and V-0 rating, respectively. The addition of 25 wt% APP/HPPU with ratio of 2:1 into PP can result in decrease in peak heat release rate of about 72%, decrease in total heat release of about 38% and decrease in TCOP of about 93%. APP/HPPU promotes PP to form more stable, compact, and continuous char layer which effectively hinder heat and oxygen transfer and protect the inner matrix from decomposition. Thermogravimetric-infrared results reveal that the gas phase flame retardant mechanism of APP/HPPU is the dilution effect of ammonia from APP and the flame inhibition effect of phosphorus-containing species from HPPU. Image 1 • A novel hyperbranched phosphorus-containing polyurethane (HPPU) is firstly synthesized. • LOI and UL-94 tests revealed that the addition of 25 wt % HPPU/APP into neat PP was able to reach 27 % and V-0 rating. • APP/HPPU exhibit remarkable flame retardant and carbon monoxide (CO) suppression to PP composites. [ABSTRACT FROM AUTHOR]

Flame retardant flexible polyurethane foam (FPUF) was prepared through a free-foaming method with aluminum diethylphosphinate (ADP) as additive. The influence of ADP on the morphology, thermal and flame retardant properties of the FPUF was investigated, and the flame retardant mechanism was further explored. TGA results indicated that the addition of ADP slightly affected the initial degradation temperature and the maximum degradation temperature. With the increase of the ADP loading, the char yield of the resultant FPUF gradually increased. When the ADP loading was 20%, the peak heat release rate and the total heat release of the resultant FPUF was reduced by 35% and 33%, respectively, compared to the unmodified FPUF. The addition of ADP improved the char formation of the FPUF, which could inhibit the transfer of oxygen and flammable gases between the flame and the underlying polymer and thus improve the fire retardancy. • Influence of ADP loading on the flame retardant property of FPUFs was studied. • The presence of ADP almost did not affect the thermal stability of FPUF. • Addition of ADP decreased the peak heat release rate and total heat release of FPUF. • ADP functioned as flame retardant in both gas phase and condensed phase. [ABSTRACT FROM AUTHOR]

Rising concerns about the toxic effects and environmental issues associated with various fireproof treatments on textiles have led to a demand for "green" materials. Chitosan (CS) is an amino polysaccharide green, recyclable, and non-toxic highly biocompatible biopolymer that consists of multiple hydroxyl groups and has a wide range of applications, including as a flame retardant additive. In this study, an eco-friendly bio-based formaldehyde-free flame retardant containing a higher level of phosphorus and nitrogen in phytic acid ammonia (PAA) was synthesized to amplify the most plentiful green chitosan (CS)-modified polyamide 66 (PA66) fabric surface through a simple pad-dry-cure technique for the improvement of durable flame retardancy with hydrophilicity. The findings revealed that each UV-grafted CS fabric could entirely stop the melt-dripping tendency during the vertical burning (UL-94) test and reached a V -1 rating. Meanwhile, limiting oxygen index (LOI) testing showed a rapid increase from 18.5 % to 24 % for the PA66 control and the PAA-treated (i.e., PA66-g-5CS-PAA) fabric samples, respectively. Moreover, compared to the PA66 control sample, a dramatic decrease in the peak heat release rate (PHRR), fire growth rate (FGR), and total heat release (THR) by approximately over 52 %, 0.63 %, and 19.7 %, respectively, was observed for the PA66-g-5CS-PAA fabric sample. Additionally, this arrangement of PAA catalyzed the charring of grafted CS and acted as a condensed phase flame retardant, resulting in a significant improvement in char yield% in both air and N 2 atmospheres for the PA66-g-5CS-PAA fabric sample in TGA. In addition, only the lower grafting ratio of CS with PAA-treated fabric sample (i.e., PA66-g-2CS-PAA) could encourage it to gain its lowest water contact angle of 00, as well as impersonating a positive effect in improving the flame retardant coating durability in washing and sustaining even after 10 home laundering cycles. This phenomenon suggests that an actual hydrophilic and durable flame retardant finishing procedure for polyamide 66 fabrics might be applied with the novel, plentiful, sustainable, and environmentally friendly bio-based green PAA ingredient. [ABSTRACT FROM AUTHOR]

• A vanillin-derived bisDOPO co-curing agent (DVD) was successfully synthesized from vanillin and DOPO. • The introduction of DVD improved the mechanical properties of epoxy thermosets. • Epoxy with an ultra-low P content of 0.42 wt% exhibited an LOI of 30.5% and reached a UL-94 V-0 rating. To prepare transparent and flame-retardant epoxy thermosets, a vanillin-derived bisDOPO co-curing agent (DVD) was synthesized from vanillin and DOPO. The influence of DVD on the curing kinetics of the epoxy systems was investigated by non-isothermal differential scanning calorimetry (DSC). The introduction of DVD increased the activation energy of the curing process. Compared with pure epoxy, the storage modulus at 30 °C and tensile strength of EP/DVD-5% increased by 35.7% and 145%, respectively. Additionally, the epoxy thermosets still maintained excellent transparency. The addition of DVD improved the flame-retardant performance of epoxy thermosets by promoting the formation of char and reducing the thermal decomposition rate. Most importantly, DVD showed high flame retardant efficiency for the resulting epoxy thermosets. Specifically, with the incorporation of 5 wt% DVD (only 0.42 wt% phosphorus loading), the resulting epoxy thermoset exhibited a limiting oxygen index (LOI) value of 30.5% and reached a UL-94 V-0 rating. The cone calorimetry results showed that the total heat release (THR), peak value of heat release rate (PHRR), and total smoke production (TSP) of EP/DVD-5% decreased by 32%, 42%, and 21%, respectively, compared with the unmodified EP. The modes of action of flame retardant analysis indicated that DVD exhibited high flame retardant efficiency by serving as a charring promotor in the condensed phase and acting as a radical scavenger in the gaseous phase. The above results demonstrate that DVD is a promising flame retardant agent to render epoxy thermosets simultaneously improved flame retardancy, mechanical strength and transparency. [ABSTRACT FROM AUTHOR]

In this work, a flowering-branch like CNTs/Bi 2 Se 3 hybrids was synthesized by a facile in-situ method. CNTs as carrier could provide low agglomeration of layered Bi 2 Se 3 . As-prepared nanomaterials were added into epoxy resin (EP) to enhance its fire safety. Compared with neat EP, there were more than 44% and 23% decrease in the value of peak heat release and total heat release with 2 wt% content of CNTs/Bi 2 Se 3 , respectively, confirmed the enhancement of flame retardancy of EP composites. Meanwhile, the release of smoke and CO were also suppressed during EP combustion. From results of thermogravimetric analysis-infrared spectrometry, the addition of CNTs/Bi 2 Se 3 obviously reduced the release of organic gaseous products, which contributed to the improved fire safety of EP matrix. Based on the analysis of gas and condensed phases, the possible enhancement mechanisms can be mainly concluded as the barrier effect of as-synthesized binary hybrids and enhanced char layers. Meanwhile, the addition of CNTs/Bi 2 Se 3 enhanced the mechanical performance of EP composites. This work broadens the application fields of Bi 2 Se 3 and enriches the membership of CNTs-based binary compounds, which were used as flame retardants. [ABSTRACT FROM AUTHOR]

• An ionic confinement engineering approach is proposed to facilitate dynamic ionic crosslinking. • The ionomers deliver low dielectric-k property, high stretchability and fast self-healing capability. • The EGaIn-infused stretchable device is designed for electronic device reconfiguration. Ionomers are gaining much attention in the fields of soft robots, flexible electronics, and artificial intelligence. However, intrinsic dynamics modulation of ionomer molecules to achieve desirable properties is highly required and challenging due to a lack of understanding of the interactions between polymerics and ionic species. In this study, a novel ionic confinement engineering approach was employed, in which the composition of a copolymer, namely, PTAE-Fe, was adjusted to facilitate dynamic ionic crosslinking, which enables high stretchability (>10000 % elongation). The proportion of ionic functional groups in PTAE-Fe significantly enhanced the self-healing efficiency up to 95 %. The ionic confinement strategy also promotes electron momentum locking, resulting in a low dielectric-k property (D k < 2.5), while a reduction in the heat release rate of 69.1 % makes the ionomer an excellent flame retardant material. In addition, a eutectic gallium-indium (EGaIn)-infused stretchable device and low D k flexible ink were designed according to the ionic confinement strategy. The as-fabricated ionomer is expected to benefit a wide range of energy and storage technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phthalocyanine-zirconium polyphosphazene functionalized BP was obtained by crosslinking reaction. • BP-ZrPZN effectively reduced the total smoke release decreased by an impressive 62.7 %. • BP-ZrPZN can comprehensively improve the fire safety and mechanical properties of EP. The existence of lone pair electrons on the surface of black phosphorus (BP) is a good electron acceptor, which has good structural stability when it forms new electron donor-electron acceptor pairs when combined with electron donators such as phthalocyanine. In order to bond functional groups available for reaction on the surface of BP, the lamellae group density was increased by functionalizing BP with benzoic acid diazonium salt, and then the carboxylated BP was covalently grafted with phthalocyanine zirconium, and finally the phthalocyanine-zirconium polyphosphazene functionalized BP (BP-ZrPZN) was obtained by crosslinking reaction. Subsequently, BP-ZrPZN was added into the EP matrix as nano filler to form the reinforced system. The results showed that the thermal stability and fire safety of EP composites containing 2 wt% BP-ZrPZN were significantly improved. The peak heat release rate and total heat release rate were reduced by 56.8 % and 54.1 %, respectively, and the limited oxygen index was up to 33 % and UL94 value was V-0. In addition, the presence of BP-ZrPZN greatly improved the ability of BP to inhibit toxic smoke. The total smoke yield of EP composites decreased by 62.7 %. The tensile strength and impact strength increased by 36.1 % and 50.6 % respectively. Therefore, the functional strategy of phthalocyanine in this work will provide a reasonable and feasible way to optimize the flame retardancy and smoke suppression effect of BP. [ABSTRACT FROM AUTHOR]

The essence of this work lies in the large-scale production of high-quality graphene sheets and simultaneous functionalization with new electrochemical route. A multifunctional flame retardant with phosphazene rings is well designed to simultaneously exfoliate and functionalize graphene. Due to the antioxidant function of flame retardant, the electrochemically-exfoliated graphene sheets exhibit high quality and low defect (C/O = 10.4). Furthermore, the obtained graphene is noncovalently modified to form flame retardant functionalized graphene sheets (FGNS). Subsequently, the FGNS is applied to improve fire safety and mechanical performance of thermoplastic polyurethane (TPU). Compared to pure sample, the peak heat release rate and total heat release of TPU composites with the addition of 4 wt% FGNS are significantly decreased by 46.3% and 20.2%, respectively. The elongation at break and tensile strength of TPU are enhanced by 11.6% and 59.9%, respectively, with the addition of 2.0 wt% FGNS. The significant enhancement in fire safety is due to conjunct effects of FGNS and the flame retardant. Lower defect of graphene provides more stable layer structure, thus FGNS plays a remarkable barrier action to confine the escape of degradation products. The coated flame retardant is conducive to form compact and robust char residue by reacting with degradation products. In addition, the flame retardant facilitates the load transfer to the robust graphene sheets with improved interface interaction. Through an electrochemical route, designing a multifunctional flame retardant to simultaneously exfoliate and modify graphene provides new possibility for the industrialized application of graphene. [ABSTRACT FROM AUTHOR]

As one of the most widely used polymers, the intrinsic brittleness and high flammability bring about a stringent requirement for the practical application of epoxy resins (EPs). It is difficult to toughen EP without compromising its mechanical and thermal properties for many conventional toughening agents. Here, a novel furan-derived bio-based polyphosphazene (PFMP) with a flexible backbone and rigid side groups was prepared by the nucleophilic substitution reaction between polydichlorophosphazene (PDCP) and furfuralcohol. The resultant PFMP was incorporated into EP to realize exceptional toughening, strengthening, and flame retardant function. By adding 15% of PFMP, the limit oxygen index value is from 25% (EP) to 33% (EP/PFMP-15) and reaches the UL-94 V-0 rating. According to the cone calorimeter results, EP/PFMP-15 exhibits exceedingly reduced peak heat release rate (pHRR) (50.2%) and total heat release (THR) (49.6%). The significantly increased fire performance index (FPI) and decreased fire growth rate index (FIGRA) of EP/PFMP-15 demonstrate an improvement in its flame retardancy. The catalytic carbonization effect (condensed phase) and radical quenching effect (gas phase) of PFMP account for the greatly improved flame retardancy. Moreover, the impact and tensile tests indicate that PFMP can ameliorate the mechanical performance of EP with a maximum increase of impact strength (111.8%) and elongation at break (35.2%) for EP/PFMP-5. With 15% PFMP added, the tensile strength of EP/PFMP-15 increases by 40.4%. This work demonstrates that PFMP is expected to overcome shortcomings (flammability, toughness, and strength) of EP and spread its applied fields. [Display omitted] • Bio-based polyphosphazene with furfuralcohol side groups (PFMP) was synthesized. • PFMP exhibits evident flame retardant and mechanical enhancement effect on epoxy resins (EP). • The peak heat release rate of EP/PFMP-15 was 50.2% lower than pure EP. • The impact strength of EP/PFMP-5 was 111.8% higher than pure EP. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new flame retardant DOPONH 2 -S was synthesized. • It solved the problems of epoxy resin (EP) including flammability and brittleness. • DOPONH 2 -S achieved high efficiency in reducing THR, P -HRR and EHC of EP. • DOPONH 2 -S increased the impact strength and thermal stability of EP. Epoxy resin (EP) has two shortcomings: flammability and brittleness. Previous studies have improved brittleness or flame retardancy but they will compromise the glass transition temperature (T g) and thermal stability. Herein, a novel DOPO based phosphorus-, nitrogen- and sulfur-co-contained macromolecular flame retardant (DOPONH 2 -S) was synthesized and incorporated into EP to improve its flame retardancy and toughness with not damaging T g and thermal stability. After curing, both T g and the tensile strength of EP-2 improved at the addition of DOPONH 2 -S is 6.75 wt%. Simultaneously, the thermogravimetric analysis (TGA) results showed DOPONH 2 -S is helpful increasing the thermal stability of EP composites and protecting the polymer from further decomposition. In the fire safety test, EP-2 achieved V-0 rating in the vertical burning test and obtained a limiting oxygen index value of 30.5%. In comparison with pure EP, the peak heat release rate, total heat release and effective heat of combustion of EP-4 incorporated with 10.0 wt% DOPONH 2 -S were reduced by 59.1%, 58.5% and 46.3%, respectively. A two-phase mechanism was discussed to explain the combination effect in DOPONH 2 -S. In condensed-phase, rich char residue prevents the exchange of mass and heat during combustion. It also obstructs the release of combustible gases into the combustion zone. In gas-phase, the produced phosphorus- and sulfur-containing free radicals can capture active free radicals (H· and OH·), thus ending the chain reaction of combustion. Moreover, the addition of DOPONH 2 -S apparently improved the impact strength (62.5%). This work provided ideas for the development of multifunctional EP. [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]

[Display omitted] • Photothermal of EP/SL-EBP-CoP is linearly increased (r2 > 0.994). • EP/SL-EBP-CoP 2 separately reduces PHRR, THR and PCOP by 59.88%, 39.26% and 36.41%. • Phosphorus, P-O-P and P-O-C are nodes, units and capture bonds in 3D sutured char. • Rupture molecules of char layer (C n H 2n+2 PO 4 , m / z = 168, 139 and 124) are discovered. To overcome the high flammability of polymers and endow them with photothermal capability, we fabricate the targeted nanofiller black phosphorus (BP) based SL-EBP-CoP for epoxy. Interestingly, the good ability of photothermal for EP/SL-EBP-CoP 2.0 nanocomposite changes with irradiation power can be linearly quantified (r2 > 0.94). Secondly, EP/SL-EBP-CoP 2.0 separately reduces peak heat release rate (HRR), total HRR and peak carbon monoxide (CO) production by 59.88%, 39.26% and 36.41% compared with EP, along with the lowest fire growth index. The significantly reduced hazard of heat and CO is attributed to the combined effects of 2D BP, catalysis of CoP and the structure of sutured char. Finally, the pyrolysis of BP-based flame retardants produces P 4 , P 3 and P 2 with an abundance of 77.10%, 6.75% and 14.70%. Moreover, flame retardant composites are highly dependent on the final char. This work demonstrates that phosphorus and P-O-P (PO x) are nodes and bonding units in the char, PO x bonds to the hydrocarbon fragments through P-O-C bonds. Particularly, pyrolysis molecules of suture and rupture of char (C n H 2n+2 PO 4 , m / z = 168, 139 and 124) are first discovered. This work booms the path and lays the foundations for the photothermal and fire safety of BP nanocomposites. [ABSTRACT FROM AUTHOR]

• Microwave assisted grafting of AA onto the PA6.6 fabric surfaces was done. • Layer by layer deposition and HP cross-linking were followed. • A maximum reduction in pHRR by ca. 50% was achieved. • Super-hydrophilic surfaces were obtained. • Such coating could retain anti-dripping properties even after 10 launderings. Microwave-assisted surface modification of polyamide 6.6 (PA6.6) fabrics was carried out in a grafting polymerization technique in the presence of acrylic acid (AA) monomer with an aim to enhance the extent of surface functional groups onto the PA6.6 fabric surfaces. In the next step, the surface modified fabric substrate was gone through a layer by layer (LbL) deposition process in the presence of some hybrid (organic/inorganic) polyelectrolytes in imparting hydrophylic and flame retardant properties and finally, the as prepared coating was subjected to a cross-linking treatment aided by hypo-phosphorus acid (HP) in enhancing the stability of the same. From the obtained results, it was revealed that the simultaneous microwave assisted grafting, LbL deposition and HP cross-linking left positive impacts in improving the flame retardant performance and hydrophilicity of PA6.6 fabrics along with the enhancement of coating stability in laundering. For example, acrylic acid grafted PA6.6 fabric sample with a 5-BL deposition and cross-linked with HP (i.e., PA6.6-g-AA-5BL-HP) attained a limiting oxygen index (LOI) value up to 23.5%, while exhibiting a significant level of reduction in the peak heat release rate (pHRR) by ca. 50 %. In line, a super-hydrophilic surface was obtained for this fabric sample as the water contact angle value declined to 0º. Furthermore, such kind of surface modification displayed a considerable level of coating stability during laundering as the anti-dripping properties still exist even after 10 home launderings. [Display omitted] [ABSTRACT FROM AUTHOR]

A fully bio-based epoxy thermosetting network was prepared by curing a renewable luteolin-derived epoxy resin (DGELU) with a furan-derived hardener, 5, 5′-methylenedifurfurylamine (DFA). For comparison, a control sample was prepared by curing the petroleum-based commercial epoxy diglycidyl ether of bisphenol A (DGEBA) with a petroleum-based hardener, 4, 4′-diaminodiphenylmethane (DDM). The glass transition temperature (T g) was found to be 216 °C for the cured DGELU/DFA, which was 67 °C higher than that of the cured DGEBA/DDM. The storage modulus at 30 °C and the tensile strength of the cured DGELU/DFA were 82.5 % and 23.2 % higher than those of the cured DGEBA/DDM. The benzopyrone unit of the luteolin structure was conducive to exceptional charring, and the char yield for thermal decomposition in the nitrogen of the cured DGELU/DFA was 3.2-fold higher than that for the cured DGEBA/DDM. As expected, the cured DGELU/DFA displays a relatively high limiting oxygen index (LOI) of 38.0 % and a UL-94 V-0 classification, whereas the petroleum-based counterpart exhibited a much lower LOI of 24.0 % and no classification in the UL-94 test. An in-vitro cytotoxicity study indicated that the cured DGELU/DFA showed no cytotoxic effect against normal fibroblast cells after 24 and 72 h. Because of these fascinating features, the DGELU/DFA thermosetting network was deposited onto wood surfaces for evaluation as a flame-retardant coating. Compared with the wood treated using the cured DGEBA/DDM coating, wood coated with the cured DGELU/DFA showed a super fire-safe property that could lead to a 55.8 %, 12.4 %, and 11.5 % decrease in peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP), respectively. An anti-flammable, high strength and non-toxic bio-derived epoxy thermosetting network for highly safe epoxy coating applications has been developed. • A fully bio-based epoxy thermoset (DGELU/DFA) has been prepared from luteolin. • DGELU/DFA showed higher Tg and tensile strength than its petroleum-based counterpart. • DGELU/DFA displayed anti-flammability with a high LOI of 38.0 % and a UL-94 V-0 grade. • DGELU/DFA showed no cytotoxic effect against normal fibroblast cells. • DGELU/DFA is suitable as a flame-retardant and eco-friendly coating for wood. [ABSTRACT FROM AUTHOR]

Polyester fabric is ubiquitously applied for clothing, furniture and transportation, whereas its flammability with severe dripping often causes secondary hazards. Herein, it is highly imperative to impart excellent flame retardant to polyester fabric. In this work, a coating for polyester fabrics was prepared through a continuous dipping and ultraviolet (UV) curing process, which exhibited high-efficiency flame-retardant, anti-dripping and washing resistance. Firstly, the surface of polyester fabric was pretreated with plasma for providing more grafting sites of polyester fabric. Then, the flame retardant 6-((((2-(acryloyloxy) ethoxy) (oxo)(phenyl)phosphonio) oxy) methyl) dibenzo[c,e][1,2]oxaphosphinine 6-oxide (DPEA) and Tri(acryloyloxyethyl) phosphate (TAEP) were successfully synthesized and applied to the coating by UV-curing. In vertical burn test, the damage length of polyester with DPEA and TAEP (PET-D 3 /T 4.5) was reduced from 300 mm of pristine PET to 100 mm with no dripping. In the Thermogravimetric Analysis (TGA) test, the char residue of PET-D 3 /T 4.5 in nitrogen increased to 26.7 % compared with 9.7 % of pristine polyester. More specifically, the Peak Heat Release Rate (PHRR) and Total Heat Rate (THR) of PET-D 3 /T 4.5 decreased 43.3 % and 22.2 % in the Micro-scale Combustion Calorimetry (MCC) test, which reflected excellent thermal stability and flame retardant properties. In addition, the Limiting Oxygen Index (LOI) of PET-D 3 /T 4.5 only dripped from 24 % to 23.5 % after ten standard laundering cycles, indicating prominent water resistance. Remarkably, Thermogravimetric Analysis-Fourier transform infrared (TG-IR), Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS) have been performed for investigating the mechanism of flame retardant. Thus, a strategy with convenience and economics is proposed, which is of gargantuan significance to the improvement of coating durability through plasma surface treatment and UV-curing. [Display omitted] • The improvement of coating durability through plasma surface treatment and UV-curing. • The damage length of coated polyester is reduced to 100 mm with no dripping. • The peak heat release rate and total heat rate of coated polyester is decreased by 43.3 % and 22.2 %. • The flame-retardant mechanism of different valence phosphorus in coating is studied. • A simple coating strategy for giving versatility to polyester fabric. [ABSTRACT FROM AUTHOR]

• A vanillin-derived cyclotriphosphazene-cored triazole compound (HHCTP) was synthesized. • The HHCTP-modified epoxy achieved a UL-94 V-0 classification and an LOI of 31.5%. • The addition of HHCTP preserved the thermo-mechanical properties of epoxy resins. A vanillin-derived cyclotriphosphazene-cored triazole compound (HHCTP) was successfully synthesized as a flame retardant for epoxy thermosets with high efficiency while preserving their thermomechanical properties. 1H- and 31P nuclear magnetic resonance (NMR), as well as Fourier Transform infrared (FT-IR), were applied to confirm the molecular structure of HHCTP. The dynamic mechanical analysis (DMA) measurements demonstrated that the introduction of HHCTP improved the storage modulus of the epoxy composites but decreased the glass transition temperature. The epoxy thermoset containing 7.5 wt% HHCTP (EP/HHCTP-7.5) achieved a UL-94 V-0 classification and an LOI of 31.5%, manifesting its outstanding flame-retardant efficiency. In addition, the cone calorimeter results showed that the total heat release (THR) and the peak value of the heat release rate (PHRR) of EP/HHCTP-7.5 were decreased by 35.6% and 50.0%, respectively, in comparison with those of the unmodified epoxy. To further study the flame retardant mechanism of HHCTP, pyrolytic gas species were detected utilizing thermogravimetric-infrared spectroscopy (TG-FTIR). In addition, the microstructure of the char residues was analyzed via X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) techniques. The phosphazene groups in HHTCP clearly stimulated the production of an intumescent, compact, and strong char layer, which improved the flame retardancy of the DGEBA matrix during burning, according to the SEM data. As a result, the underlying components were protected from further degradation and combustion, resulting in effective flame retardancy of the DGEBA thermoset. [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 novel cactus-like structure of BP@MoS 2 hybrids was designed and synthesized. • The tensile strength and fracture strength of WPU/BP@MoS 2 -2.0 increase by 57.7% and 36.5%. • The PHRR and TSP of WPU/BP@MoS 2 -2.0 reduce by 50.3% and 52.0%. • BP and MoS 2 have a cooperative effect in suppressing the heat release behavior of WPU/BP@MoS 2. Design novel flame retardant and mechanical enhancing agents of waterborne polyurethane (WPU) is a crucial issue for expanding its application. Herein, BP@MoS 2 hybrids was designed and prepared to enhance the fire safety and mechanical properties of WPU and BP@MoS 2 possessed a novel cactus-like structure. BP@MoS 2 was prepared in a two-step method including preparation of black phosphorus (BP) sheets by chemical vapor transfer method and preparation of BP@MoS 2 by in situ growth of molybdenum disulfide (MoS 2). with adding 2.0wt% BP@MoS 2 , the tensile strength and fracture strength of WPU/BP@MoS 2 -2.0 increase by 57.7% and 36.5%, respectively. The peak value of heat release rate (PHRR) and total smoke production (TSP) of WPU/BP@MoS 2 -2.0 also reduce by 50.3% and 52.0%, which indicates that fire safety and mechanical performance of WPU/BP@MoS 2 -2.0 is effectively enhanced. Meanwhile, BP@MoS 2 has both condensed phase and gas phase flame retardant effect on WPU. In condensed phase, the residue char of WPU/BP@MoS 2 is with excellent physical barrier effect. In gas phase, BP@MoS 2 can inhibit the generation of flammable volatiles such as aromatic and aliphatic compounds during burning of WPU/BP@MoS 2 , thereby inhibiting the heat release and smoke release behavior of WPU/BP@MoS 2. [Display omitted] [ABSTRACT FROM AUTHOR]