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A 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) derivative is prepared. At first, an intermediate 4,4'‐((triazole)bis(azaneylylidene)bis(2,6‐dimethoxyphenol)) (SGA) is obtained from the Schiff‐base reaction between syringaldehyde (S) and 3,5‐diamino‐1,2,4‐triazole (GA). The further product DOPO‐SGA is then introduced into epoxy by blending to improve flame retardancy and mechanical properties. The flammability evaluation is implemented by limited oxygen index (LOI), UL‐94, and cone calorimeter tests. The presence of 3wt.% DOPO‐SGA increases the LOI to 33.2%, upgrades the UL‐94 rating to V‐0, and reduces the release of smoke and heat of epoxy. The tensile strength and impact strength are also enhanced after the introduction of DOPO‐SGA. The addition of 5% DOPO‐SGA increases the tensile strength and impact strength by 47% and 42%, respectively, compared with that of the control EP sample. It is suggested that the mechanical strengthening is ascribed to the ternary cross‐linked network among epoxy monomer, curing agent, and DOPO‐SGA. This work provides a feasible solution to obtain flame‐retardant epoxy resin with enhanced mechanical performance. [ABSTRACT FROM AUTHOR]

[Display omitted] Despite the advantages of easy moulding and excellent mechanical properties, there are still some shortcomings with polypropylene (PP) such as high flammability and poor ultra-violet (UV) resistance. In this work, modified zinc oxide (mZnO) was prepared by reacting zinc oxide nanoparticles (ZnO) with polysiloxanes, and the effect of mZnO on the effectiveness of intumescent flame-retardant and on the UV aging resistance of polypropylene were investigated. By introducing 16 wt% (intumescent flame-retardant /mZnO) and 0.3 wt% maleic anhydride-grafted PP (MAH-g-PP), the limiting oxygen index increased to 32.7 %, and passed UL-94V-0 rating. In comparison to the controls, the peak heat release rate and the peak smoke release rate were 88.5 % and 80 % lower, respectively. In addition, PP samples showed improved mechanical properties, with a 5 % increase in tensile properties compared to the pure PP sample. After 100 h of UV irradiation, the surface of the samples was relatively flat and smooth, and the carbonyl index decreased from 81.1 of neat PP to 26.7. PP composites with 100 h aging treatment still had excellent flame retardancy and mechanical properties. The results showed that mZnO was effective in improving the flame retardancy, mechanical properties and light aging tolerance of PP. This study provides a novel approach to fabricate long-life flame-retardant PP composites with low additive content. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium-sulfur batteries (LSBs) have become highly promising next-generation secondary lithium batteries owing to their high theoretical energy density and abundance of sulfur. Nevertheless, the large-scale application of LSBs is still restricted by the shuttle effect of lithium polysulfide (LiPSs) and the potential fire hazard caused by flammable electrolytes. Herein, three electrolyte-insoluble brominated flame retardants (BFRs) are selected and coated on both sides of commercial polypropylene separators by a facile slurry coating method. The effects of the three BFRs on the safety and electrochemical properties of LSBs are characterized and compared. The coating modification separators greatly improves the flame retardancy of LSBs through radical elimination mechanism. The self-extinguishing time of the electrolyte is reduced from 0.66 s/mg to 0.20 s/mg. Moreover, it is demonstrated that the oxygen (O)-containing BFRs exert a significant adsorption capacity and are more advantageous than O-free BFRs in LSBs. In addition, octabromoether (BDDP) coated separator is more effective in trapping LiPSs than decabromodiphenyl ether (DBDPO) due to higher O content, which can mitigate the shuttle effect and enhance the cycle and rate performance of LSBs. This simple coating strategy for separators with BFRs offers a strongly competitive option for the large-scale production of high-safety LSBs. [ABSTRACT FROM AUTHOR]

High efficient flame retardant surface treatment through a simple and universal strategy has attracted considerable interest. In this work, polyphosphonamide (PPA) was synthesized via an eco-friendly amine ester exchange reaction, and then the polydopamine-polyphosphonamide (PDA-PPA) coating was constructed by a mussel-inspired phenol-amine co-deposition on the surface of various substrates (cotton, polyethylene terephthalate, poly (lactic acid), polyamide, polypropylene fabrics, and flexible polyurethane foam). It was demonstrated that the PDA-PPA coating significantly improved the flame retardancy of the six substrates. For example, in the case of PDA-PPA coated cotton fabric sample, the limiting oxygen index was increased to 28.3%, the peak of heat release rate and total heat release was decreased by 70.6% and 48.2%, respectively. Especially in the vertical and horizontal burning tests, all PDA-PPA coated samples were self-extinguished and free of molten droplets. It was suggested that the PDA-PPA coating released P-containing radicals to capture active small free radicals and released non-combustible gases to dilute combustible volatiles in the gas phase. In addition, the coating showed excellent intumescent charring ability and promoted the char formation of all substates except polypropylene. Surprisingly, the coating also improved the breaking strength of the PDA-PPA coated fabric and the compressive stress of the PDA-PPA coated foam samples. It was believed that this work provides a scalable and promising strategy for preparing fire safety polymeric materials with a large specific surface area. [Display omitted] • Polyphosphonamide (PPA) was synthesized by an eco-friendly approach. • Polydopamine (PDA) -PPA coating was constructed on the surface of six substrates. • All PDA-PPA coated samples were self-extinguished and free of molten droplets. • The PDA-PPA coating exerted a comprehensive inhibition on combustion. • A facile, universal strategy for flame retardant surface treatment was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based lentinan (LNT) and ammonium phytate (APA) were introduced onto cotton fabric. • The flame retardancy of cotton fabric was significantly enhanced by the presence of APA and LNT. • The LNT outer layer improved the thermostability, durability, and breaking force of the APA-treated cotton fabric. As the most widely used natural fabric, cotton fabric is highly flammable with serious fire hazard concerns. The use of biomass materials to impart flame resistance to fabrics is always a hot topic of interest. In this work, a novel durable flame retardant cotton fabric (Cotton-APA/LNT) was fabricated by successively covalent bonding ammonium phytate (APA) and lentinan (LNT). The Cotton-APA/LNT fabric sample had a highly limiting oxygen index (LOI) value of 51.5 % and was self-extinguished in the vertical burning test (VBT) at 18.0 % weight gain. The peak heat release rate and total heat release values were decreased by 91.5 % and 46.0 %, respectively compared with those of the control cotton. Besides, after 50 laundering cycles (LCs), the fabric was still self-extinguished in the VBT with an LOI value of 34.2 %. APA fully strengthened the role of acid source by the presence of LNT. The constructed LNT outer layer showed comprehensive improvements in thermostability, flame retardancy, smoke suppression, durability, and breaking force. Specifically, the Cotton-APA/LNT sample had a higher LOI value (↑4.3 %), lower total heat release (↓23.8 %), lower total smoke production (↓29.1 %), higher thermostability (↑27 °C under air), better char formation ability (↑2.0 % under air), higher durability (self-extinguished in the VBT after 50 LCs), and higher breaking force (↑32.5 % in the warp direction and ↑33.9 % in the weft direction) compared with those of Cotton-APA sample. This work has proposed an advanced approach for fabricating eco-friendly durable fire-safety cotton fabrics. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel bio-based nano-flame retardant with core–shell structure (PA-Fe-HBT) are prepared. • PA-Fe-HBT improved the flame retardancy, UV resistance and recyclability of PLA. • The corresponding mechanisms are proposed. Polylactic acid (PLA) is one of the solutions to the white pollution and energy crisis. However, the using performance (such as flame retardant, weather resistance and mechanical properties) and recycling performance limit its wide application. In this work, a bio-based additive (PA-Fe-HBT) with core–shell structure is synthesized by tannins microspheres and phytic acid (PA). By the presence of 3 wt% PA-Fe-HBT, the limited oxygen index is increased to 25.5%, and the sample can pass UL-94 V-0 grade. At the same time, the mechanical properties of the composites remain good. Besides, the ultraviolet aging resistance and ultraviolet protection ability of the composite are significantly improved. The ultraviolet (UV) transmittance of PLA/3%PA-Fe-HBT sample shows a decrease of 99.97% compared with control PLA. More importantly, the chemical recycling of composites is promoted by PA-Fe-HBT in the absence of external heating. After a simple purification, 88% purity of lactic acid is obtained. It is believed that this work proposes an ingenious design strategy to prepare PLA/PA-Fe-HBT composites with flame-retardancy, UV resistance and chemical recycling performances. [ABSTRACT FROM AUTHOR]

The incorporation of flame retardants (FRs) is often applied to reduce the fire risk of flexible polyurethane foam (FPUF), however, the addition of FRs usually brings mechanical loss, and the emigration of FRs during service life results in a decrease in flame retardancy. In this work, a hyperbranched FR (HPNP) containing nitrogen and phosphorous was synthesized via transesterification between dimethyl methyl phosphonate (DMMP) and triethanolamine. The distribution of HNPN in FPUF was simulated by the Materials Studio software. The flammability was characterized by the open flame test, horizontal combustion test, limiting oxygen index (LOI) and cone calorimeter test. The FPUF sample containing only 4 wt% HPNP self-extinguished immediately after the removal of the ignitor. For the FPUF containing 8 wt% HPNP sample, the LOI was increased to 26.3% from 17.9%. The total heat release and total smoke production were reduced by 65% and 75%, respectively compared to that of the control FPUF sample. More importantly, the radical trapping action in the gas phase and the charring promotion in the condensed phase were simulated and verified based on the experimental data. Furthermore, the interfacial energy calculation and molecular dynamics simulation suggested that the improved compatibility of FPUF/HPNP resulted in the superior durability of HPNP in FPUF. In addition, the FPUF samples containing HPNP also showed enhanced mechanical properties. It was expected the hyperbranched HPNP would be an ideal additive to produce flame retardant FPUF with excellent comprehensive performance. [Display omitted] • A hyperbranched flame retardant (HPNP) was synthesized by transesterification. • FPUF containing 8 wt%HPNP showed self-extinguish effect with an LOI of 26.3%. • Total smoke release of FPUF was greatly reduced by the presence of 8 wt% HPNP. • The addition of HPNP also enhanced the mechanical properties of FPUF. • The improved compatibility of HPNP and FPUF suppressed the emigration of HPNP. [ABSTRACT FROM AUTHOR]

It is still a big challenge for textile industry in improving fire resistance and reducing melt dripping with minimal loss on the physical properties of polyethylene terephthalate (PET) fabrics. In this work, a highly-effective hyperbranched flame retardant (DT) was first synthesized by ester exchange without using any organic solvent. Then, the DT foam was prepared and blade coated on PET fabric to improve the fire performance. The prepared PET fabric with only 2.7% weight gain of DT was self-extinguished and did not produce any molten dripping during the vertical flammable test. The peak heat release rate and total heat release of the PET fabric sample with 19.4% DT were decreased by 42.0% and 57.1%, respectively compared with that of the control PET. Besides, the as-prepared PET fabric sample showed better physical properties such as breaking strength, vapor permeability, air permeability, antistatic property, and softness than the control PET fabric sample. The DT foam finishing process did not involve any organic solvent and consumed less water and energy compared with conventional fabric treatments. It is expected that this work provides a facile and eco-friendly strategy for fabricating flame retardant PET fabric with excellent comprehensive performances. [Display omitted] • A hyperbranched flame retardant (DT) was synthesized by a solvent-free approach. • Flame retardant PET fabrics were prepared by sustainable foam finishing. • The PET fabric with 2.7% DT was self-extinguished and free of molten drops. • The treated PET fabric showed excellent physical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Formaldehyde-free durable flame-retardant cotton fabrics were prepared. • The fabric had an LOI of 35.3% and was self-extinguishing after 300 washing cycles. • The durability was reinforced by the interface polymerization of PEI and TMC. Due to fire hazards and environmental concerns, considerable attention has been paid to the design of durable flame retardant fabrics. In this work, a formaldehyde-free flame retardant cotton fabric (Cotton-PEI/APP-TMC) with ultra washing durability was prepared via covalent bonding of ammonium polyphosphate (APP) and polyethyleneimine (PEI) followed by the interface polymerization between PEI and trimesoyl chloride (TMC). The prepared fabric exhibited excellent flame retardancy with a limiting oxygen index value (LOI) of 42.0 % and a damaged length of less than 40 mm in the vertical flammability test (VFT). Besides, the cotton-PEI/APP-TMC sample was not ignited in the 50 kW/m2 cone calorimeter test with a dramatic decrease in both the peak heat release rate and total heat release. Even after 300 washing cycles, the cotton-PEI/APP-TMC sample had an LOI value of 35.3 % and was still self-extinguishing in VFT. It was demonstrated that the interface polymerization between PEI and TMC stabilized the flame retardant coating and shielded the Na+ during washing cycles, which endowed the fabric with durable flame retardancy. It is expected this work paves a promising application prospect for the fabrication of bio-safe durable flame retardant cotton fabrics. [ABSTRACT FROM AUTHOR]

Flexible polyurethane foam (FPUF) is widely used in our life, but it is inherent flammable. The demand for environmental-friendly multi-functional FPUF has been increasing rapidly in the last decade. In this work, a novel bio-based flame retardant coating was constructed by chemically reacting sodium alginate (OSA) and polydopamine (PDA) on the FPUF, followed by depositing nanorod-like β-FeOOH molecules through complexation reaction to form a biomimetic structure. The limiting oxygen index of the coated FPUF samples reached 25.5%. The peak heat release rate was reduced by 45.0%, and the smoke density of the coated sample was decreased by 69.1% compared to that of the control FPUF sample. It was proposed that the OSA-PDA-β-FeOOH decomposed during combustion to promote the formation of compact crosslinked char and released inert gases to dilute the combustible gases, and the β-FeOOH transferred to Fe 2 O 3 to settled the smoke particles reducing the smoke release. Furthermore, the coating with shark skin like structure endowed FPUF antibacterial ability because of its good superoleophobicity underwater. This work provided a novel strategy to construct a biomimetic multifunctional coating on the FPUF. [Display omitted] • A biobased coating was constructed on flexible polyurethane foam (FPUF). • The coating with a biomimetic structure improved the flame retardancy of FPUF. • The LOI of the coated FPUF reached 25% after washing and/or abrasion. • The coating decreased the peak smoke density of FPUF by 68.5%. • FPUF with superoleophobicity underwater showed antibacteria for cleaning application. [ABSTRACT FROM AUTHOR]

An integrated multi-functional additive was fabricated by successively grafting melamine (MEL) and phytic acid (PhA) on multiwalled carbon-nanotubes (MWNCTs), and was then applied in PA6 to improve the flame retardancy and light aging resistance of the composite. The limit oxygen index of PA6 composite containing 7 wt% PhA-MEL-MWCNTs was increased to 26.4 from 21.0. The smoke and CO release were significantly reduced by 48% and 88% respectively, and the severe melt dripping of PA6 in burning was eliminated. It is proved that PhA-MEL-MWCNTs can absorb ultraviolet (UV) radiation, and hence significantly reduces the mechanical property loss of the PA6 composite after UV aging. The tensile strength of the aged PA6/7 wt%PhA-MEL-MWCNTs composite sample only decreased by 18.1%, which was significantly lower than the loss rate of the control aged PA6 sample (62.5%). This protocol provides a new opportunity for fabricating long-life flame retardant polyamide composites. [Display omitted] • PhA-MEL-MWCNTs was fabricated by grafting melamine and phytic acid on MWCNTs. • PhA-MEL-MWCNTs improved flame retardancy and light aging resistance of PA6. • The melt dripping of PA6 was eliminated by 7% PhA-MEL-MWCNTs. • The mechanical loss of PA6 after UV aging was reduced by PhA-MEL-MWCNTs. • The potential danger of PA6 in dairy usage was reduced. [ABSTRACT FROM AUTHOR]