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To improve the flame retardancy of phenolic foam from the perspective of sustainable development, it is a feasible way to add bio-based flame retardants into phenolic foam. Lignin has a similar structure to phenol, which provides a possibility to replace part of phenol. In this paper, we prepared a kind of reactive bio-based flame retardant based on enzymatic hydrolyzed lignin, in which side chain was chemically grafted with phosphorus and nitrogen and benzene ring would participate in the phenolic condensation reaction. According to elemental analysis and ICP-OES data, the content of nitrogen and phosphorus in modified lignin (NP-L) increased to 2.95% and 3.55% respectively. Compared with original lignin, the carbon residue rate of NP-L increased from 3.25% to 12.13% because of the presence of flame retardant elements N and P. Then lignin-based flame retardant was used to replace phenol for modifying phenolic foams (NPLPFX). The limited oxygen index (LOI) and compressive strength of phenolic foam were improved effectively by adding modified lignin when the substitution rate was less than 25%. The LOI and compressive strength of the modified phenolic foam with 5% replacement amount (NPLPF5) are 55.6% and 0.24 MPa, which increased by 88% and 60% compared with pure phenolic foam. The cone calorimetric data also showed that NPLPF5 had good flame retardancy, and the peak heat release rate and total heat release were significantly lower than PF. This work suggests a novel green strategy for improving the flame retardancy performance of phenolic foam and promoting the utilization of lignin. [ABSTRACT FROM AUTHOR]

A trade‐off dilemma exists for simultaneously improving the mechanical properties and flame resistance of flexible polyvinyl chloride (fPVC)/magnesium hydroxide (MH) composites. In this study, epoxy phosphate ester (EPE), a hydrophobic surface modifier of MH, was synthesized using a self‐emulsification method. After modification, EPE was bonded to the surface of MH (MHEPE) without altering its morphology. The results of limiting oxygen index and cone calorimetry tests indicated that fPVC/MHEPE exhibited better flame retardancy and smoke suppression effects than did fPVC/MH. The peak of the heat release rate, total heat release, peak of the smoke production rate, and total smoke production of the fPVC/MHEPE composite were 206.0 kJ m−2, 45.90 MJ m−2, 0.0729 m2 s−1, and 9.88 m2, which were 8.64%, 14.00%, 27.61%, and 9.02% lower than those of the fPVC/MH composite, respectively. For the fPVC/MHEPE composite, a compact and continuous char residue formed, which could inhibit heat and flammable volatile migration between the matrix and burning zones. In the gas phase, the dilution effect of H2O vapor reduced the concentrations of O2 and flammable volatiles. The free‐radical quenching effect of ·PO and ·PO2 also played a vital role in extinguishing flame and terminating combustion. Further, the introduction of EPE improved the tensile and impact strengths of the fPVC/MH composites because of the excellent interfacial compatibility between MHEPE and the fPVC matrix. This study provides a simple and workable solution for the trade‐off dilemma, and the remarkable flame retardancy and mechanical properties of the fPVC/MHEPE composite render it a promising cable material. [ABSTRACT FROM AUTHOR]

For effectively strengthening the comprehensive properties of intumescent flame‐retardant epoxy resins (EPs), a microencapsulating γ‐Fe2O3 by polypyrrole (PPy) named PPy‐Fe2O3 was synthesized and used as a synergist to simultaneously enhance the flame retardancy, smoke toxicity suppression and mechanical strength of EP composites containing diaminodiphenylmethane modified ammonium polyphosphate (DDP). The results demonstrate that the mixture of PPy‐Fe2O3 and DDP exhibits a surprising synergistic effect on strengthening the comprehensive properties of EP composites. Specifically, EP composite containing 0.2 wt% PPy‐Fe2O3 and 9.8 wt% DDP achieves the UL94 V‐0 rating with a limiting oxygen index (LOI) value of 35.5%, while 10 wt% DDP only imparts a UL94 V‐1 rating and a LOI value of 34.0% to EP. Furthermore, 0.2 wt% PPy‐Fe2O3 shows a 11.0% reduction in peak smoke production rate and a 12.3% reduction in peak heat release rate of the EP/DDP system. The enhanced fire security of EP/DDP/PPy‐Fe2O3 is attributed to the formation of more phosphorus‐rich structures retained in the char, thus reducing the release of harmful gases including NH3, CO, and CO2, and generating more incombustible gases including H2O to weaken burning intensity. Meanwhile, the satisfactory compatibility of PPy‐Fe2O3 with epoxy matrix imparts a superior mechanical strength to EP composites. [ABSTRACT FROM AUTHOR]

Two porous zirconium silicates were synthesized by the interaction of cubic octa(tetramethylammonium)silicate with zirconium oxychloride. The results show that the porosity of the obtained products depends on the synthesis conditions. The surface area of porous zirconium silicate ZrSi‐1 synthesized at room temperature was 3.45 m2/g, and the surface area of porous zirconium silicate ZrSi‐2 synthesized when heated to 65 °C was 23.77 m2/g. X‐ray diffraction data from ZrSi‐1 and ZrSi‐2 show that their structure is amorphous. The synthesized porous silicates were used as modifiers for intumescent fire‐retardant coatings. The obtained intumescent coatings were tested in a muffle furnace at 600 °C. It was found that the use of porous zirconium silicate in intumescent coatings increases their char expansion, which indirectly shows that the porous zirconium silicate increases the flame‐retardant properties of intumescent coating. Moreover, it was shown that the use of zirconium silicate with higher porosity leads to higher char expansion and as a result to higher efficiency of the fire‐retardant coating. So, the non‐modified coatings, coatings with 0.5 % ZrSi‐1, coatings with 0.5 % ZrSi‐2, coatings with 1 % ZrSi‐1, coatings with 1 % ZrSi‐2, had the char expansion of 17, 23, 32, 36, 38 times, respectively. [ABSTRACT FROM AUTHOR]

Polyurea (PUA) is widely used as a coating in construction, tunnels, bridges, and other fields because of its excellent performance. However, its combustion emits toxic gases and smoke, hindering escape and posing potential fatality risks. Enhancing the flame retardancy of PUA is crucial for safety and expanding its applications. The synthesis of two‐dimensional FePP nanosheets was reported in this paper, employing the solvothermal method, followed by the sequential growth of MoS2 and Ni‐MOF to establish a multilayer composite structure. The elemental composition and morphology of the synthesized FePP@MoS2@Ni‐MOF flame retardants were characterized and analyzed. The flame retardant properties of polyurea composites with varying amounts of FePP@MoS2@Ni‐MOF were investigated using Cone calorimeter tests. The results showed that the prepared flame retardant had good thermal stability and significantly improved fire safety properties. The PUA/FePP@MoS2@Ni‐MOF 3.0 composite exhibited notable improvements compared to pure PUA. Specifically, the peak heat release rate, total heat release rate and peak smoke production rate were reduced by 39.76%, 29.33% and 17.86%, respectively, while total smoke production and total CO production (COP) were reduced by 21.30% and 54.47%. This study provides new insights and experimental basis for the technological development of novel flame retardant coating materials. [ABSTRACT FROM AUTHOR]

Imparting good flame retardancy and mechanical properties to epoxy resin (EP), while pursuing the sustainable and safe application of EP, we synthesized a novel reactive phosphorus/nitrogen flame retardant for biomass through nucleophilic addition reaction, which contains flexible ether bonds and rigid aromatic ring structure (DVD). Owing to the cooperative effect of aryl ether diamine, phosphorus phenanthrene, and biomass vanillin, the DVD exhibited excellent flame retardancy. EP/DVD‐1 (0.4 wt% phosphorus content) achieved UL‐94 V‐0 rating, with an improvement in limiting oxygen index value from 26.5% (pure EP) to 32.5%. In the CCT, the modified DVD EP showed a 44.5% reduction in peak peak of heat release rate (PHRR) and a 38.0% reduction in total heat release compared to pure EPs. And flame retardant epoxy resin (FREP) still had good transparency after the addition of DVD, which indicated the nice compatibility between DVD andEP. What was noteworthiness was that at high levels of addition, the mechanical properties of modified EP for DVD was still improved compared to pure EP. These results demonstrate that DVD is an excellent and multifunctional bio‐based flame retardant with broad application prospects in the field of EP material modification. [ABSTRACT FROM AUTHOR]

The production of polyurethane foam (PUF) from green and sustainable agricultural waste reeds could replace traditional petroleum-based PUF. In this paper, reed naturally contains nano-SiO2.was liquefied to reed-based polyol (R-P) using Castor oil and PEG-400 as a compound solvent and H2SO4 as a catalyst, The liquefaction efficiency is as high as 97.16%; Reed-based polyurethane foam (R-PUF) was prepared with R-P, water, and isocyanate by one-pot and free rise method. Moreover, DOPO with a rigid ring and Phosphorus was introduced into the cross-linked structure of rigid PUF as a reactive-type flame retardant. The mechanical properties, microstructure, thermal stability, and flame retardance of the R-PUFs were investigated, The results showed that the density of R-PUF was 33.03 kg/m3, the thermal conductivity was 0.0350 W/(m·K), and the limiting oxygen index (LOI) was 20.5%, which was higher than petroleum-based polyurethane; the 6%-DOPO PUF has better flame retardant and thermal stability. The mechanism of R-PUF added DOPO is intrinsic flame retardant and the result of the presence of the gas phase inhibiting the combustion chain reaction and the coalescence phase blocking the transfer of oxygen and heat to the interior of the foam. [ABSTRACT FROM AUTHOR]

Tripropyl phosphate (TnPP) is a commonly used organic phosphate flame retardant in the textiles, plastics, and coating industries. Residues are commonly detected in samples from the environment and food. The availability of certified reference materials (CRMs) is essential to ensure the accuracy and traceability of detection results. In this study, a comprehensive characterization of a CRM for TnPP was carried out, and its purity was evaluated using two distinct methodologies: mass balance (MB) and quantitative nuclear magnetic resonance spectroscopy (qNMR). In the MB method, the levels of structurally related organic impurities are 1.37 mg/g. The water content was determined to be 3.16 mg/g, while inorganic impurities were found to be 0.87 mg/g, and no residual organic solvents were detected. Benzoic acid and monocrotophos were chosen as internal standards for 1H-qNMR and 31P-qNMR, respectively. The purity of the TnPP CRM was assessed as 994.6 mg/g, 994.1 mg/g, and 993.5 mg/g using MB, 1H-qNMR, and 31P-qNMR techniques, respectively. The verified purity of the TnPP CRM was ultimately determined to be 994.1 mg/g, with an expanded uncertainty of 3.4 mg/g (k = 2), ensuring traceability to the International System of Units (SI). This CRM can be effectively utilized for preparing calibration solutions suitable for the routine monitoring of TnPP residues in plastics and food samples. [ABSTRACT FROM AUTHOR]

Cotton fabric (CF) was coated with a new multifunctional flame-retardant system consisting of melamine phosphate (MP) and nickel (II) dimethylglyoxime (NDMG). The new coating was applied to enhance the flame retardancy, antibacterial activity, thermal stability, color strength, UV protection, and electrical properties of CF. The weight percentages of NDMG and MP that led to the maximum improvement in CF properties were identified. According to vertical and horizontal flammability tests, coating the fabric with 29%MP/1%NDMG prevented flame propagation in the samples. Moreover, it increased the limiting oxygen index (LOI) of CF from 17.9% to 36.9%. Thermogravimetric analysis (TGA) data presented that the MP/NDMG coating enhanced the char residue at 750°C. Antimicrobial investigations indicated that the coating 29%MP/1%NDMG reduced the growth of S. aureus and E. coli bacteria. UV shielding and color strength (K/S) results revealed that coated fabrics had excellent UV protection (UPF > 175) and enhanced K/S values. The tensile strength of CF was slightly decreased after the coating process. The dielectric constant (ε'), the dielectric loss (ε''), and AC electrical resistivity ( ρ A C ) with frequency (10-106 Hz) were also investigated. The electrical resistivity increased significantly after adding MP and NDMG to the CFs. The coated sample (23%MP/7%NDMG) showed the best dielectric properties, with a low dielectric constant of 2.6 and ρ A C of 1.40E+10 Ω.cm at 1000 Hz. [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]

Safe operation of electrochemical capacitors (supercapacitors) is hindered by the flammability of commercial organic electrolytes. Non‐flammable Water‐in‐Salt (WIS) electrolytes are promising alternatives; however, they are plagued by the limited operation voltage window (typically ≤2.3 V) and inherent corrosion of current collectors. Herein, a novel deep eutectic solvent (DES)‐based electrolyte which uses formamide (FMD) as hydrogen‐bond donor and sodium nitrate (NaNO3) as hydrogen‐bond acceptor is demonstrated. The electrolyte exhibits the wide electrochemical stability window (3.14 V), high electrical conductivity (14.01 mS cm−1), good flame‐retardance, anticorrosive property, and ultralow cost (7% of the commercial electrolyte and 2% of WIS). Raman spectroscopy and Density Functional Theory calculations reveal that the hydrogen bonds between the FMD molecules and NO3− ions are primarily responsible for the superior stability and conductivity. The developed NaNO3/FMD‐based coin cell supercapacitor is among the best‐performing state‐of‐art DES and WIS devices, evidenced by the high voltage window (2.6 V), outstanding energy and power densities (22.77 Wh kg−1 at 630 W kg−1 and 17.37 kW kg−1 at 12.55 Wh kg−1), ultralong cyclic stability (86% after 30 000 cycles), and negligible current collector corrosion. The NaNO3/FMD industry adoption potential is demonstrated by fabricating 100 F pouch cell supercapacitors using commercial aluminum current collectors. [ABSTRACT FROM AUTHOR]

Highly flame‐resistant epoxy composites have important application value in many industrial fields. Unfortunately, epoxy resins (EPs) are inherently flammable materials and exhibit great fire hazard. In this study, the commercially available 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was chemically immobilized on the surface of natural halloysite nanotubes (HNTs) via the linkage of vinyltrimethoxysilane to obtain a novel flame‐retardant VD@HNTs containing P/Si/Al elements. It was found that the flame‐retardant VD@HNTs can effectively improve the thermal stability and flame resistance of epoxy composites. Typically, when 10% of VD@HNTs is added in EP, the limiting oxygen index of as‐prepared VD@HNTs/EP composites reaches 30.3%, and it also successfully reaches V‐0 classification in the UL‐94 test. Besides, the ignition time of VD@HNTs/EP composites was enhanced from 42 s for pure EP to 60 s, and the maximum heat release rate was reduced from 1221 to 758 kW∙m−2. These great findings promise an innovative and efficient strategy for improving the fire safety of EP products and may also offer valuable insight toward fabricating various novel organic–inorganic flame retardants as well as highly flame‐resistant polymer composites. Highlights: A novel flame‐retardant VD@HNTs containing P/Si/Al elements was prepared by the chemical decoration of HNTs with organophosphorous.The VD@HNT can effectively improve the thermal stability and flame resistance of epoxy composites.Synergistic flame‐retardant mechanism of phosphorus‐based flame retardants and natural HNTs was classified. [ABSTRACT FROM AUTHOR]

Alkyl hypophosphate flame retardants have aroused intense research interests in flame retardancy of polymers owing to the combined effect of gas phase and condensed phase. In this work, aluminum diisobutyl hypophosphate (APBA) was incorporated into polyethylene glycol terephthalate (PET) to investigate its flame retardant effect and mechanism. PET achieved a V‐2 level in UL‐94, with a low LOI of 21.2%. In contrast, PET/APBA‐15% composites showed a 51% increase of LOI value and a V‐0 level, accompanied with the significant reduction of melt droplets. Gas phase analysis by Py‐GC/MS and TG‐FTIR indicated that the phosphorous free radicals and nonflammable gases were generated during the cracking of APBA, resulting in the radical quenching and dilution of combustible gas. Condensed phase analysis by SEM, Raman, and XPS results revealed that APBA could effectively facilitate the formation of dense char layers consisting of aluminophosphate and graphitic structures due to the interaction with PET matrix. The compact barrier layer could insulate heat and inhibit the volatilization of combustible materials, leading to improved flame retardant properties. Furthermore, the introduction of APBA increased the melt viscosity of PET/APBA composites according to rheological analysis, which further promoted the formation of a char barrier layer to further enhance the flame retardant properties. Highlights: Aluminum diisobutyl hypophosphate is used as an efficient flame retardant for PET.The flame retardant can degrade to release the phosphorous free radicals.The flame retardant can interact with the PET matrix and promote the charring. [ABSTRACT FROM AUTHOR]

The zirconium‐based metal–organic framework material (UiO‐66‐NH2) was synthesized by solvothermal method, and its excellent adsorption performance was used to combine it with the phosphorus‐based flame retardant triethyl phosphate (TEP) and to improve the flame retardant and smoke suppression properties of epoxy resin (EP). The morphology, chemical composition, and structure of the synthesized flame retardant were analyzed by scanning electron microscope, energy dispersion spectrum, Fourier transform infrared spectroscopy, and x‐ray diffractometer. The cone calorimeter measurement of EP composite materials shows that EP composite materials have good flame retardant and smoke suppression properties. Compared with EP, after the UiO‐66‐NH2 flame retardant which adsorbs TEP is added, the peak heat release rate, total heat release, peak smoke release rate, total smoke production, carbon monoxide release rate, and carbon dioxide release rate of EP composites have been reduced. From the results of thermal analysis and scanning electron microscope, it can be seen that the synthesized flame retardant can act both in the condensed phase and in the gas phase. Thereby, the combustion of the matrix and the diffusion of the toxic gas, smoke and heat generated during the combustion are inhibited, and the flame retardant and smoke suppression effects are achieved. Highlights: Make full use of the excellent adsorption performance of MOF.TEP was fully adsorbed in UiO‐66‐NH2 pores.UiO‐66‐NH2 in synergy with TEP improves EP flame retardancy. [ABSTRACT FROM AUTHOR]

In this study, novel durable flame-retardant lyocell fibres were designed by the addition of phosphorylated cellulose and physical blending of montmorillonite (MTT) within the fibres. The influences of phosphorylation and MTT blending on the flame retardancy of lyocell fibres were investigated. Additionally, the synergistic effects of the two flame retardant methods were also discussed. Furthermore, phosphorylated cellulose and MTT-filled lyocell fibres were prepared, and their flame retardancy was measured. Phosphorylation (limiting oxygen index (LOI) > 28%) was found to improve the flame retardancy of the lyocell fibres; nevertheless, excessive phosphorylation decreased the crystallinity of the cellulose and decreased the mechanical strength of the fibres. Montmorillonite was added to the lyocell fibres to achieve durable flame retardancy, whereas the LOI was less than 24%. Interestingly, lyocell fibres with LOIs greater than 28% and strengths greater than 2.0 cN/dtex could be obtained from the phosphorylated cellulose with MTT filling. The thermogravimetric (TG) and TG-infrared (TG-IR) experimental results showed that MTT played a role in the condensed-phase flame retardancy, while phosphorylated cellulose played a role in the gas-phase and condensed-phase flame retardancy. The Raman test results showed that the combination of MTT and phosphorylated cellulose enhanced the graphitization degree of the residue char. In our study, a novel flame-retardant method for the preparation of lyocell fibres with permanent flame retardancy and high tensile strength was developed; moreover, our results contribute to the development of industrial-grade fabrication of new flame-retardant fibre materials. [ABSTRACT FROM AUTHOR]

A novel phosphorus-containing cotton flame retardant 2, 6-dimethoxy polysaccharose phosphonic acid ester ammonium phosphonate (DOPSPAP) was synthesized and its chemical structure was confirmed by nuclear magnetic resonance (1H, 13C and 31P NMR) and Fourier infrared spectroscopy (FT-IR). The damage length of the cotton fabric treated with 25wt% DOPSPAP was only 4.2 cm in the vertical flame test (VFT), and the char residue was observed to maintain the intact fiber structure by scanning electron microscopy (SEM). The limiting oxygen index (LOI) of 25wt% DOPSPAP treated cotton fabric was as high as 44.5%, and the LOI was still 34.5% after 50 LCs according to AATCC 61–2013 3A standard. SEM observed the presence of DOPSPAP flame retardant on the surface of cotton fiber. Durability, FT-IR and energy dispersive X-ray spectroscopy (EDS) confirmed the grafting of DOPSPAP on cotton fibers through P(= O)-O-C covalent bonds. The cone calorimetric results showed that DOPSPAP effectively inhibited the heat release during combustion of cotton fabrics. The thermogravimetric (TG) and TG-FTIR results suggested DOPSPAP changed the decomposition pathway of cotton fibers and promoted their dehydration into char. The bending length and tensile strength of DOPSPAP-treated cotton fabrics are well maintained. Compared with 2, 6-dimethoxy polysaccharide ammonium phosphonate (DOPSAP), DOPSPAP-treated cotton fabric showed better flame retardant durability and tensile strength. The EDS results showed that the metal ion content of DOPSPAP-treated cotton was significantly lower than that of DOPSAP-treated cotton after 50 LCs. These results indicate that the simultaneous introduction of phosphonic acid ester and ammonium phosphonate groups into flame retardants can not only improve the durability of flame retardants, but also reduce the loss of strength. [ABSTRACT FROM AUTHOR]

Chlorinated bisphenol A (BPA) derivatives are formed during chlorination process of drinking water, whereas bisphenol S (BPS) and brominated BPA and BPS (TBBPA and TBBPS) were synthesized for many industrial uses such as fire retardants. However, the effect of halogenated BPA and BPS derivatives on glucocorticoid metabolizing enzyme 11β‐hydroxysteroid dehydrogenase 1 (11β‐HSD1) remains unclear. The inhibitory effects of 6 BPA derivatives in the inhibition of human and rat 11β‐HSD1 were investigated. The potencies for inhibition on human 11β‐HSD1 were TBBPA (IC50, 3.87 μM) = monochloro BPA (MCBPA, 4.08 μM) = trichloro BPA (TrCBPA, 4.41 μM) > tetrachloro BPA (TCBPA, 9.75 μM) > TBBPS (>100 μM) = BPS (>100 μM), and those for rat 11β‐HSD1 were TrCBPA (IC50, 2.76 μM) = MCBPA (3.75 μM) > TBBPA (39.58 μM) > TCBPA = TBBPS = BPS. All these BPA derivatives are mixed/competitive inhibitors of both human and rat enzymes. Molecular docking studies predict that MCBPA, TrCBPA, TCBPA, and TBBPA all bind to the active site of human 11β‐HSD1, forming hydrogen bonds with catalytic residue Ser170 except TCBPA. Regression of the lowest binding energy with IC50 values revealed a significant inverse linear regression. In conclusion, halogenated BPA derivatives are mostly potent inhibitors of human and rat 11β‐HSD1, and there is structure‐dependent inhibition. [ABSTRACT FROM AUTHOR]

Rigid polyurethane foam (RPUF) was prepared using hydrolyzed keratin‐modified polyol and aluminium hypophosphite as flame retardants. The effects of aluminium hypophosphite on the thermal stability and flame‐retardant properties of hydrolyzed keratin‐modified RPUFs were studied by limiting oxygen index (LOI) method, thermogravimetric analysis, pyrolysis kinetic analysis, cone analysis and smoke density analysis. The results showed that RPUF added with 7.5 wt% aluminium hypophosphite (RPUF‐HK5‐7.5AL) had the highest LOI, which was 26.1%. RPUF‐HK5‐7.5AL had the highest initial decomposition temperature, the highest T5% at a heating rate of 10 °C min−1 and the highest activation energy. In addition, RPUF‐HK5‐7.5AL possessed the lowest heat release rate at 50 kW m−2 of 125.10 kW m−2, and the lowest total heat release rate of 5.30 MJ m−2. Results indicated that RPUF‐HK5‐7.5AL had the best thermal stability and flame‐retardant properties. Scanning electron microscopy showed that hydrolyzed keratin and aluminium hypophosphite had a synergistic effect on the flame retardancy of the RPUFs. The current research results provide a useful reference for the preparation of RPUFs with good flame‐retardant properties by bio‐based modification. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

A sulfur-containing polyphosphonate compound, polysulfonyldiphenylene phenylphosphonate (PSPPP), was prepared based on diphenylphosphine and bisphenol S, and applied to flame retarded polyethylene terephthalate (PET). The flame retardancy and thermal stability of PSPPP/PET composites were investigated by limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimeter and thermogravimetric analysis (TGA). LOI value increased from 20.5% for pure PET to 29.2% for flame retardant PET with 8 wt.% PSPPP, and 8%PSPPP/PET passed UL-94 V-0 rating. The cone calorimeter test displayed that PSPPP not only inhibited the maximum combustion strength of PET composites but also suppressed the smoke release. TGA results indicated that PSPPP significantly enhanced the char yield of composites and the thermal stability of residues at higher temperature. The flame retardant modes of action of PSPPP were confirmed by experiments using TGA-Fourier transform infrared (TGA-FTIR), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), Hot-Stage FTIR, and scanning electron microscope (SEM). PSPPP played a role of flame retardant in condensed phase and gas phase. During combustion, PSPPP continuously released phosphorus-oxygen-free radicals with quenching effect, thus playing the gas phase flame retardant effect. On the other hand, the transesterification reactions between PSPPP and PET promoted the formation of dense carbon layer and led to high barrier effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electronic products sorted by black, white or other color are called chromoproducts. • Chromoproducts were categorized according to their likelihood of POP-BFRs content. • Chromoproduct approach used to sort polluted/clean plastic at e-waste facilities. • Bromine and antimony contents by weight might be indicators of POP-BFRs pollution. • Chromoproducts composition and plastics separated by polymer type allowed upcycling. Research to prevent releases of brominated flame retardants listed as persistent organic pollutants by the Stockholm Convention (POP-BFRs) was conducted through an international cooperation project in Colombia. Six waste electrical and electronic equipment (WEEE) management facilities implemented: 1) sorting e-waste by product type and color (black, white, and other; henceforth called chromoproducts), 2) sampling test products and their plastic fraction (called sets, separated by polymer type), 3) monitoring mass, bromine and antimony contents by hand-held X-ray fluorescence (XRF) and POP-BFRs such as polybrominated diphenyl ethers (PBDEs) by gas chromatography and mass spectrometry (GC–MS), and 4) differentiated treatment according to categories that used the Restriction of Hazardous Substances in Electrical and Electronic Equipment Directive (RoHS) hazardousness threshold of 1000 mg ∑PBDEs/kg. This scheme led to the proposal of a methodology for WEEE management called the "chromoproduct approach". 994,230 products were managed and grouped into 222 chromoproducts, from which 77 were analyzed: 50 below RoHS hazardousness (BRH), 16 above RoHS hazardousness (ARH), and 11 unknown RoHS hazardousness (URH). XRF indicators using bromine and antimony contents could rule out pollution in BRH chromoproducts; however, categorization still required GC–MS. One ARH plastics sample had 3620 mg ∑PBDEs/kg, while no POP-BFRs were found in the BRH plastics sample. The implementation of the chromoproduct approach traced 153.6 tonnes of ARH plastics. BRH plastics composition was estimated and used in a pilot-scale closed-loop economic activity. The chromoproduct approach seems promising for avoiding POP-BFR releases and promoting the upcycling of recyclable e-waste plastics. [ABSTRACT FROM AUTHOR]

In this paper, flame retardant composites were prepared by incorporating three flame retardants (FRs), including triphenyl phosphate (TPP), polysiloxane (PSQ) and phosphite functionalized polysiloxane (PPSQ), respectively into a polylactic acid (s/PLLA) matrix. The results indicated that the ultimate oxygen index increased from 20.6% (s/PLLA) to 22.5% (s/PLLA/TPP), 21.1% (s/PLLA/PSQ), and 23.3% (s/PLLA/PPSQ). The composites exhibited a decrease in peak heat release rate (pHRR) and prolonged peak time according to the cone calorimetry analysis. s/PLLA/PPSQ possessed the highest residual carbon content and the densest char residue with finest and smallest pores, indicating excellent flame-retardant performance. The crystallization behavior analysis revealed that the three FRs resulted in an increased crystallization rate and crystallinity. Notably, the crystallinity of s/PLLA/PPSQ increased from 25.8% in s/PLLA to 37.3%. Additionally, PSQ and PPSQ effectively enhanced the mechanical properties of composite materials. Compared to s/PLLA, the tensile strength of s/PLLA/PSQ and s/PLLA/PPSQ increased by 11.5% and 31.3% respectively, and storage modulus increased by 50.0% and 14.6%. This research demonstrated that among the three additives, PPSQ can effectively provide both flame retardancy and mechanical properties to the s/PLLA matrix, resulting in the composite with the best comprehensive performance. [ABSTRACT FROM AUTHOR]

As the SARS-CoV-2 virus continues to spread and mutate, it remains important to focus not only on preventing spread through vaccination but also on treating infection with direct-acting antivirals (DAA). The approval of Paxlovid, a SARS-CoV-2 main protease (Mpro) DAA, has been significant for treatment of patients. A limitation of this DAA, however, is that the antiviral component, nirmatrelvir, is rapidly metabolized and requires inclusion of a CYP450 3A4 metabolic inhibitor, ritonavir, to boost levels of the active drug. Serious drug-drug interactions can occur with Paxlovid for patients who are also taking other medications metabolized by CYP4503A4, particularly transplant or otherwise immunocompromised patients who are most at risk for SARS-CoV-2 infection and the development of severe symptoms. Developing an alternative antiviral with improved pharmacological properties is critical for treatment of these patients. By using a computational and structure-guided approach, we were able to optimize a 100 to 250 µM screening hit to a potent nanomolar inhibitor and lead compound, Mpro61. In this study, we further evaluate Mpro61 as a lead compound, starting with examination of its mode of binding to SARS-CoV-2 Mpro. In vitro pharmacological profiling established a lack of off-target effects, particularly CYP450 3A4 inhibition, as well as potential for synergy with the currently approved alternate antiviral, molnupiravir. Development and subsequent testing of a capsule formulation for oral dosing of Mpro61 in B6-K18-hACE2 mice demonstrated favorable pharmacological properties, efficacy, and synergy with molnupiravir, and complete recovery from subsequent challenge by SARS-CoV-2, establishing Mpro61 as a promising potential preclinical candidate. [ABSTRACT FROM AUTHOR]

Proteinaceous brain inclusions, neuroinflammation, and vascular dysfunction are common pathologies in Alzheimer's disease (AD). Vascular deficits include a compromised blood-brain barrier, which can lead to extravasation of blood proteins like fibrinogen into the brain. Fibrinogen's interaction with the amyloid-beta (Aß) peptide is known to worsen thrombotic and cerebrovascular pathways in AD. Lecanemab, an FDA-approved antibody therapy for AD, clears Aß plaque from the brain and slows cognitive decline. Here, we show that lecanemab blocks fibrinogen's binding to Aß protofibrils, preventing Aß/fibrinogen-mediated delayed fibrinolysis and clot abnormalities in vitro and in human plasma. Additionally, we show that lecanemab dissociates the Aß/fibrinogen complex and prevents fibrinogen from exacerbating Aß-induced synaptotoxicity in mouse organotypic hippocampal cultures. These findings reveal a possible protective mechanism by which lecanemab may slow disease progression in AD. [ABSTRACT FROM AUTHOR]

The efficient and environmentally friendly removal of halogen substituents from organic substances is crucial for reducing the ecological and health hazards posed by persistent halogenated compounds. In this regard, we introduce CoN3P1@NP-PC, a novel asymmetric CoN3P1 single-atom catalyst, which demonstrates outstanding efficiency in transfer hydrodehalogenation (HDH) using just two equivalents of HCOONH4 as a benign and effective reducing agent. This catalyst was synthesized through a simple post-implantation method, capitalizing on the high porosity and large surface area of ZIF-8 precursors. Extensive characterization via a range of spectroscopic and microscopic techniques confirmed CoN3P1@NP-PC's superior atomic dispersion and asymmetric structural integrity, which was more favourable for HCOONH4 activation allowing facile generation of hydrogen radicals along with electron transfer. In our comprehensive evaluation, CoN3P1@NP-PC displayed outstanding versatility for the transformation of a diverse array of halogenated substrates, efficiently processing compounds with varied functional groups and complex molecular structures. Notably, CoN3P1@NP-PC proved particularly effective in breaking down brominated flame retardants such as 2,4,6-tribromophenol and tetrabromobisphenol A, reinforcing its potential as a powerful tool for ecological restoration and pollution control. [ABSTRACT FROM AUTHOR]

Polymeric thermal insulation materials, especially polyurethane foams (PUF), are widely used in buildings to diminish the energy penalty but highly flammable. To reduce the flammability and smoke release of polyurethane foams without sacrificing the inherent properties, we report an efficient strategy involving pulsed chemical vapor deposition (Pulsed-CVD) and spray atomization to generate a phosphorous/SiO2 nanolayer with a thickness below 200 nm on polydopamine modified rigid polyurethane foams. Due to the unique multilayers structure, the resultant composites showed an extra-ordinary thermal conductivity of 31.9 mW m−1 K−1 and enhanced compressive strength of 42%. Notably, the surface-treated PUF was hard to ignite in vertical test and had a very high limited oxygen index (LOI) value of 34.3%. Cone calorimetry (CC) results revealed that the total heat release (THR) and the total smoke release (TSR) were reduced by 32.9% and 64.3%, respectively. And the close-cell char structure was perfectly retained after CC test. The mechanism research suggested that silica and phosphorus promoted char formation, limited heat release and thermal degradation during combustion. These results indicate the strategy with a mild process has potential for industrialization with superior fire safety and structure stability in polymeric insulation materials. The polydopamine (PDA)-coated commercial polyurethane foam was treated through the pulsed-CVD and spray atomization strategy, the surface was decorated with flame retardant layers, and the flame and fumes were efficiently suppressed by instant char-forming and dense surface carbon barrier without sacrificing its inherent properties. [ABSTRACT FROM AUTHOR]

Hybrid composite's flame retardancy properties play a dynamic role in structural applications. When inorganic nanomaterials form organic/inorganic nanocomposites, they exhibit superior flame‐retardant effects. Therefore, the current work investigates the combined effects of halogen‐free fire‐retardant ammonium polyphosphate (APP) and graphene (GR) nanofillers on the mechanical, and fire‐resistant behavior of hybrid composite fabricated using a vacuum bag process. Mechanical study affirmed that the concurrent incorporation of APP and GR hybrid composite improved the hardness, flexural, and tensile properties by 7%, 26%, and 16%, respectively. Scanning electron microscopy (SEM) confirms that the dispersion of 0.75 wt% GRs improved the mechanical properties by preventing crack propagation and strong binding between fiber‐matrix in the hybrid composite. The vibrational analysis reveals an improved natural frequency (NF) value was obtained with 0.75 wt% GR; further addition of GR increased the damping due to an increase in nanoparticle agglomeration. The combined effect of APP and GR decreased the hybrid composite's water uptake and porosity by 52% and 80%, respectively. The flammability study (Vertical burning) affirmed that the composite's grade score was improved from V‐1 to V‐0. Therefore, the current study emphasizes that this optimized hybrid composite can be utilized in fire‐sensitive structural applications. Highlights: UL‐94 VB test reveals the flammability of the hybrid composite.Examine the combined effect of APP and GR in strength and flame‐retardant properties.GR and APP added sample shows better mechanical and flame resistance properties.The optimized wt% of GR and APP for better results is 0.75% and 9.25%.The prepared composite may suitable fire‐sensitive structural applications. [ABSTRACT FROM AUTHOR]

Currently, the flame‐retardant modification of polybutylene succinate (PBS) is mainly focused on improving flame‐retardant efficiency, ignoring the negative impact of the smoke produced by combustion on the human respiratory tract. To address this problem, PBS composites were prepared by melt blending method in this study. The effect of boron nitride‐grafted DOPO flame retardant (BNNS@DOPA) on flame retardancy and smoke suppression of PBS composites was investigated. Incorporating 3% BNNS@DOPA into PBS composites results in a 90% improvement in thermal conductivity. This resulted in a reduction of the peak heat release rate, total heat release rate, and actual smoke rate to 453.7 kW m−2, 86.3 MJ m−2, and 1035.9 m2, respectively, compared with pure PBS. The latter indicated a decrease of 34.0%, 37.6%, and 51.2%, respectively. Furthermore, the ignition time was extended by 45 s and the limiting oxygen index value increased by 12.5%. This functionalization approach presents a new way to study PBS flame retardancy improvement, consequently boosting its application in fire safety for polymer materials. [ABSTRACT FROM AUTHOR]

It is of great importance to enhance ability of charring formation for polystyrene (PS) to overcome non‐charring feature during burning. Here, we demonstrate a kind of ternary intumescent flame retardant composition composed by a novel ionic liquid butyltriphenylphosphonium‐chelated orthoborates (IL) with self‐expanded flame retardant, ammonium polyphosphate (APP) and expandable graphite (EG), to improve flame retardancy of PS. This ternary composition promotes limited oxygen index (LOI) value to 26.6 ± 0.5% and UL‐94 V0 level for PS composite with 15 wt% total loading. In addition, the peak value of heat release rate and smoke production rate of PS composite with ternary composition are separately reduced by 79.7% and 70.7% comparing to neat PS as well as 44.4% and 29.2% to its IL‐free binary counterpart in cone calorimeter test. Meanwhile, the ternary composition displays compact charring bulk constructed by large‐expansion‐volume vermiform expanded graphite. The TG‐FTIR technique is used to analyze gaseous profiles. The rheological property discloses that expansion behavior of the ternary composition contributes to robust viscoelasticity of composite and advantageous network construction at high temperature. Given the fire performance of the ternary composition, the combination of IFR and IL provides an opportunity for rational design and fabrication of functional flame‐retardant system. [ABSTRACT FROM AUTHOR]

The widespread industrial applications of thermoplastic polyurethane (TPU) are partially limited by its flammability. The design of high‐performance intumescent flame retardants (IFR) is of great significance for enhancing flame retardant (FR) performance of TPU. In this work, an IFR system consisting of ammonium polyphosphate (APP), double pentaerythritol (DPER), and zinc borate (ZB) is proposed. The optimized experimental parameters with 15 wt.% additive amount of FR, APP‐DPER weight ratio of 2.28:1 and 15.56 wt.% ZB content are regulated based on Box–Behnken design‐response surface methodology (BBD‐RSM) to obtain TPU/FR composite with superior limiting oxygen index value of 30.2%. Noticeably, the design efficiency of TPU/FR composite is significantly improved by utilizing BBD‐RSM. Results of vertical burning test show that the optimized TPU/FR composite passes UL 94 V‐0 rating and peak heat release rate is dramatically reduced from 1355.88 (neat TPU) to 201.01 KW/m2 through cone calorimeter test. In addition, scanning electron microscopy accompanied with Raman spectroscopy are conducted to characterize the morphology and composition of residual char for further exploring the FR mechanism of IFR system in TPU. The as‐prepared TPU/FR composite has provided new potential application in engineering fields. [ABSTRACT FROM AUTHOR]

Widening the voltage window of the nickel‐rich layered oxide cathode‐based lithium metal batteries (LMBs) can effectively improve the energy density of rechargeable batteries. However, serious safety issues associated with the high reactivity between LiNi0.8Co0.1Mn0.1O2 (NCM811) and electrolyte at high cut‐off voltage remains challenging. Herein, a flame‐retardant electrolyte with the ability to form a robust armor‐like electrode electrolyte interphase (EEI) with LiF and LixByOz compounds for stabilizing Li||NCM811 batteries is proposed. Such electrolyte exhibits the high thermal stability with flame‐retardant effect for ensuring the battery safety at high voltage. The armor‐like EEI can effectively protect both NCM811 and lithium (Li) for improving the battery cycling performance. As a result, the capacity retention rate of the NCM811 cathode with such electrolyte reached 68% after 150 cycles at 4.6 V. This work provides an effective reference for the reasonable design of high‐voltage, flame‐retardant electrolytes for LMBs. [ABSTRACT FROM AUTHOR]

Solid‐state lithium metal batteries (SSLMBs) have gained extensive attraction as one kind of next‐generation energy storage device. However, the drawbacks of flammability, low mechanical strength, and low ionic conductivity limit the further development of solid‐state polymer electrolytes (SPEs). In this work, a reactive flame‐retardant unit into the polymer framework via covalent bonding to create a nonflammable and stretchable polyurethane‐based SPEs is introduced. Meanwhile, the mechanical strength of the polymer backbone is increased by grafting a rigid benzene ring unit, which remarkably suppresses the lithium‐dendrite growth. As a result, these inflammable SPEs do not burn after contact with flames for 6 s. Furthermore, the obtained SPE expands the electrochemical stability window up to 5.1 V. Small monomers containing bromine decompose on the surface of lithium metal creating a LiBr riched solid electrolyte interface (SEI). Li|SPEs|Li symmetric battery offers a stable cycling life for more than 2100 h at 0.2 mA cm−2 and 0.2 mAh cm−2. The LiNi0.6Co0.2Mn0.2O2|SPEs|Li cell equipped with the integrated cathode delivers a 142.1 mAh g−1 capacity after 330 cycles at 0.3 C with 85.2% capacity retention. [ABSTRACT FROM AUTHOR]

Halogen-free organophosphorus flame retardants have promising application prospects due to their excellent safety and environmental protection properties. A cobalt-coordinated cyclic phosphonitrile flame retardant (Co@CPA) was synthesized via a hydrothermal method using hexachlorocyclotriphosphonitrile (HCCP), 5-amino-tetrazolium (5-AT), and cobalt nitrate hexahydrate (Co(NO3)2∙6H2O) as starting materials. The structure was characterized using Fourier transform infrared (FTIR), nuclear magnetic resonance spectroscopy (1H-NMR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Thermoplastic polyurethane (TPU) composites were prepared by incorporating 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphame-10-oxide (ODOPB), Co@CPA, and silicon dioxide (SiO2) via melt blending. The flame-retardant performance and thermal stability of the TPU composites were evaluated through limiting oxygen index (LOI), vertical combustion (UL-94), TG, and cone calorimetric (CCT) tests. SEM and Raman spectroscopy were used to analyze the surface morphology and structure of the residual carbon. A synergistic flame-retardant effect of ODOPB and Co@CPA was observed, with the most effective flame retardancy achieved at a TPU:ODOPB:Co@CPA:SiO2 ratio of 75:16:8:1. This composition exhibited an LOI value of 26.5% and achieved a V-0 rating in the UL-94 test. Furthermore, compared to pure TPU, the composite showed reductions in total heat release, CO production, and CO2 production by 6.6%, 39.4%, and 48.9%, respectively. Our research findings suggest that Co@CPA demonstrates outstanding performance, with potential for further expansion in application areas. Different metal-based cyclic phosphonitrile compounds are significant in enriching phosphorus-based fine chemicals. [ABSTRACT FROM AUTHOR]

Graphene-like 2D nanomaterials, such as graphene, MXene, molybdenum disulfide, and boron nitride, present a promising avenue for eco-friendly flame retardants. Their inherent characteristics, including metal-like conductivity, high specific surface area, electron transport capacity, and solution processability, make them highly suitable for applications in both structural fire protection and fire alarm systems. This review offers an up-to-date exploration of advancements in flame retardant composites, utilizing pristine graphene-like nanosheets, versatile graphene-like nanosheets with multiple functions, and collaborative systems based on these nanomaterials. Moreover, graphene-like 2D nanomaterials exhibit considerable potential in the development of early fire alarm systems, enabling timely warnings. This review provides an overview of flame-retarding and fire-warning mechanisms, diverse multifunctional nanocomposites, and the evolving trends in the development of fire alarm systems anchored in graphene-like 2D nanomaterials and their derivatives. Ultimately, the existing challenges and prospective directions for the utilization of graphene-like 2D nanomaterials in flame retardant and fire-warning applications are put forward. [ABSTRACT FROM AUTHOR]

Weak bonds usually make macromolecules stronger; therefore, they are often used to enhance the mechanical strength of polymers. Not enough studies have been reported on the use of weak bonds in flame retardants. A water-soluble polyelectrolyte complex composed of polyethyleneimine (PEI), sodium tripolyphosphate (STPP) and melamine (MEL) was designed and utilized to treat bio-based polyamide 56 (PA56) by a simple three-step process. It was found that weak bonds cross-linked the three compounds to a 3D network structure with MEL on the surface of the coating under mild conditions. The thermal stability and flame retardancy of PA56 fabrics were improved by the controlled coating without losing their mechanical properties. After washing 50 times, PA56 still kept good flame retardancy. The cross-linking network structure of the flame retardant enhanced both the thermal stability and durability of the fabric. STPP acted as a catalyst for the breakage of the PA56 molecular chain, PEI facilitated the char formation and MEL released non-combustible gases. The synergistic effect of all compounds was exploited by using weak bonds. This simple method of developing structures with 3D cross-linking using weak bonds provides a new strategy for the preparation of low-cost and environmentally friendly flame retardants. [ABSTRACT FROM AUTHOR]

Polymeric materials, renowned for their lightweight attributes and design adaptability, play a pivotal role in augmenting fuel efficiency and cost-effectiveness in railway vehicle development. The tailored formulation of compounds, specifically designed for additive manufacturing, holds significant promise in expanding the use of these materials. This study centers on poly(lactic acid) (PLA), a natural-based biodegradable polymeric material incorporating diverse halogen-free flame retardants (FRs). Our investigation scrutinizes the printability and fire performance of these formulations, aligning with the European railway standard EN 45545-2. The findings underscore that FR in the condensed phase, including ammonium polyphosphate (APP), expandable graphite (EG), and intumescent systems, exhibit superior fire performance. Notably, FR-inducing hydrolytic degradation, such as aluminum hydroxide (ATH) or EG, reduces polymer molecular weight, significantly impacting PLA's mechanical performance. Achieving a delicate balance between fire resistance and mechanical properties, formulations with APP as the flame retardant emerge as optimal. This research contributes to understanding the fire performance and printability of 3D-printed PLA compounds, offering vital insights for the rail industry's adoption of polymeric materials. [ABSTRACT FROM AUTHOR]

A widely used organophosphate flame retardant (OPFR), triphenyl phosphate (TPP), is frequently detected in various environmental media and humans. However, there is little known on the human corneal epithelium of health risk when exposed to TPP. In this study, human normal corneal epithelial cells (HCECs) were used to investigate the cell viability, morphology, apoptosis, and mitochondrial membrane potential after they were exposed to TPP, as well as their underlying molecular mechanisms. We found that TPP decreased cell viability in a concentration-dependent manner, with a half maximal inhibitory concentration (IC50) of 220 μM. Furthermore, TPP significantly induced HCEC apoptosis, decreased mitochondrial membrane potential in a dose-dependent manner, and changed the mRNA levels of the apoptosis biomarker genes (Cyt c, Caspase-9, Caspase-3, Bcl-2, and Bax). The results showed that TPP induced cytotoxicity in HCECs, eventually leading to apoptosis and changes in mitochondrial membrane potential. In addition, the caspase-dependent mitochondrial pathways may be involved in TPP-induced HCEC apoptosis. This study provides a reference for the human corneal toxicity of TPP, indicating that the risks of OPFR to human health cannot be ignored. [ABSTRACT FROM AUTHOR]

Differentiation of pancreatic endocrine cells from human pluripotent stem cells (PSCs) has been thoroughly investigated for application in cell therapy against diabetes. In the context of induced pancreatic endocrine cell implantation, previous studies have reported graft enlargement resulting from off-target pancreatic lineage cells. However, there is currently no documented evidence of proliferative off-target cells beyond the pancreatic lineage in existing studies. Here, we show that the implantation of seven-stage induced PSC-derived pancreatic islet cells (s7-iPICs) leads to the emergence of unexpected off-target cells with proliferative capacity via in vivo maturation. These cells display characteristics of both mesenchymal stem cells (MSCs) and smooth muscle cells (SMCs), termed proliferative MSC-and SMC-like cells (PMSCs). The frequency of PMSC emergence was found to be high when 108 s7-iPICs were used. Given that clinical applications involve the use of a greater number of induced cells than 108, it is challenging to ensure the safety of clinical applications unless PMSCs are adequately addressed. Accordingly, we developed a detection system and removal methods for PMSCs. To detect PMSCs without implantation, we implemented a 4-wk-extended culture system and demonstrated that putative PMSCs could be reduced by compound treatment, particularly with the taxane docetaxel. When docetaxel-treated s7-iPICs were implanted, the PMSCs were no longer observed. This study provides useful insights into the identification and resolution of safety issues, which are particularly important in the field of cell-based medicine using PSCs. [ABSTRACT FROM AUTHOR]

It is imperative to develop efficient flame retardants to solve the issues of high heat and smoke release for epoxy resin (EP) polymeric materials plagued over time. Hence, a phosphorus–nitrogen modified Ti3C2Tx MXene nanohybrids (MXene@MPA) were synthesized by in situ assembly melamine phytate macromolecules (MPA) to boost the fire hazards of EP composites. The introduction of MPA improved the dispersion of MXene in epoxy matrix, contributing to the improved thermal stability and flame-retardant properties for EP composites. With the addition of 2 mass% MXene@MPA, EP composites achieved the decreased maximum mass loss rate (MLRmax) by 41.8%, indicating the enhanced thermal properties. Also, the peak heat release rate (PHRR) and peak smoke production rate (PSPR) of EP-MXene@MPA composites were down by 27.9% and 43.6% compared to pure EP, respectively, accompanied by significantly increased char production. The synergistic effects between MPA and MXene contributed to the elevated fire safety of EP-MXene@MPA composites: the catalytic charring of transition metals and phosphorus-containing acid and the barrier effect of MXene nanosheets, as well as the quenching effects of phosphorus–oxygen free radicals and dilution of nitrogen-containing inert gases due to the decomposition of MPA. The multiple hybridization route provided a reference for the development of efficient MXene-based flame retardants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sorting lines reject around 40% of waste electrical and electronic equipment (WEEE). • Unsortable mixed plastics from post-consumer WEEE have been compatibilized. • SEBS-30 led to reduced phase segregation and improved fracture surface. • Differential Scanning Calorimetry showed 20% SEBS-30 increased polymer interaction. • 20% SEBS-30 yielded mechanical performance comparable to that of virgin polymers. While near-infrared (NIR) spectroscopy in post-consumer waste electrical and electronic equipment (WEEE) recycling accurately separates white or clear polymers, 40% containing dark plastics, termed 'unsortable WEEE,' are excluded from sorting lines and therefore incinerated or landfilled, causing environmental concerns. This study investigates the potential of using non-reactive and reactive copolymers as compatibilizers to enhance the performance of unsortable WEEE plastics free of brominated flame retardants. To the best of our knowledge, this is the first time that such copolymers have been explored as a solution for improving the compatibility of unsortable WEEE polymer blends. Initial trials with 4% of styrene-ethylene-butylene-styrene copolymer (SEBS-13) and SEBS-30-g-(maleic anhydride) copolymer (SEBS-30-g-MA MA) as compatibilizers showed insufficient results compared to virgin commercial polymers. However, the addition of higher concentrations of compatibilizers (i.e. up to 20 wt%) and the use of a SEBS having a higher styrene content (i.e. SEBS-30) improved the mechanical properties of the material, causing it to transition from brittle to ductile. This behavior was found more pronounced for the 20% non-reactive SEBS-30, for which the SEM analysis showed reduced phase segregation and revealed a more homogeneous fracture surface. This was further supported by Differential Scanning Calorimetry (DSC) analysis, which showed evidence of an interaction between one or more polymer phases. With a room temperature performance equivalent to that of virgin conventional polymers, the SEBS-30 compatibilization approach has made it possible to consider using unsortable WEEE streams as recycled materials in commercial applications. [ABSTRACT FROM AUTHOR]

Given the widespread use as flame retardants, plasticizers, and organophosphate esters (OPEs) received increasing scientific interests on their occurrence and ecotoxicological research progress. This review comprehensively conducted bibliometric analysis and surveyed the OPEs occurrence in aquatic ecosystem (water, sediment, and aquatic organisms) and human-related (drinking water and sewage) over the past decade to unraveling knowledge gaps. The OPEs concentrations in water, sediment were at the range of not detected (n.d.) or several to hundreds ng/g or ng/L and exhibited landuses-specific characteristics. The electronic waste (e-waste) processing activities and sewage discharge were identified as point sources of OPEs in aquatic environment. Emission source intensity, water chemistry, and content of organic carbon were important for the partition and transfer processes of OPEs in the water, as well as hydrophobicity of OPEs dominating the absorption on the organic matter. Degradation, especially photodegradation and reductive degradation, has application potential in improving removal efficiencies of chlorinated-OPEs (Cl-OPEs) being reluctant to degrade. Generally, most surveyed OPEs have negligible ecological and health risks, whereas those OPEs with moderate threats or chronic effects on aquatic ecosystem should gain more attention. This review elucidates the status of OPEs pollution in water and highlights the need for more transport and degradation studies on traditional and emerging OPEs and metabolites to further identify potential threats on aquatic ecosystem. [ABSTRACT FROM AUTHOR]

[Display omitted] Thermal runaway is a hazardous risk, occurring more readily in high-energy–density lithium-ion batteries (LIBs), which leads to a rapid temperature rise and even combustion or explosion when using flammable electrolyte systems. Flame retardants (FRs), such as trimethyl phosphate (TMPa) and triethyl phosphate (TEP), are commonly utilized due to their effective flame suppression, low toxicity, and excellent thermal stability. However, the lack of in-depth understanding of the flame retardancy mechanism and solid electrolyte interphase (SEI) formation process has made the development of functional electrolytes difficult at present. In this study, we clarified the flame retardancy and interfacial reaction mechanisms of low-flammable TMPa localized high-concentration electrolytes (LHCE) using hybrid ab initio and reactive force field (HAIR) schemes. Long-term HAIR simulation reveals that phosphorous radicals produced by the decomposition of TMPa capture carbon radicals, encouraging their polymerization into low-flammable oligomers, while fluorine-containing solvents in the electrolyte capture hydrogen radicals and produce nonflammable hydrofluoric acid (HF). This synergistic flame retardancy mechanism provides essential atomic-level insights for the rational design of high-safety electrolytes in the future. [ABSTRACT FROM AUTHOR]

In this investigation, characterization and comparison of the flame retardant performance were conducted for polylactic acid (PLA)/fiber composites featuring the incorporation of different flame retardants (APP, PAPP, and DMH). Based on the results obtained from the Limiting Oxygen Index (LOI) test and cone calorimeter test, it is evident that the intumescent flame retardants (IFR) such as APP and PAPP exhibit better efficacy on improving flame retardancy than DMH. The LOI value of the APP/PLA/F and PAPP/PLA/F composite reaches 35.5% and 27.4%, higher than that of DMH/PLA/F (23.0%). The pk‐HRR of APP/PLA/F and PAPP/PLA/F decreases 27% and 39% compared with PLA/F while the char residue at 500°C was higher than that of DMH/PLA/F (0.3 wt%) with the value of 51.4 and 44.1 wt%. It should be mentioned that the impact strength and tensile strength of PLA/fiber composite incorporating APP surpasses that of PAPP/PLA/F, which is caused by good dispersibility of fabrics among the PLA matrix, coupled with the strengthened interfacial adhesion between the fibers and the polylactic acid matrix. In summary, APP/PLA/F shows the most overall performance. Highlights: Properties of PLA/fiber composites with various fire retardants were compared.APP/PLA/F obtained the best overall property while DMH/PLA/F had the worst.APP endows composites with excellent flame retardancy and mechanical property.The LOI value of APP/PLA/F was 35.3%, highest among four composites.Adding APP to PLA/F led to an increase in tensile strength and impact strength. [ABSTRACT FROM AUTHOR]

Kapok fiber (KF) with a naturally hollow structure has found an increasing application in filling and composite materials, most of which have a demand of flame retardancy. To realize this high-value utilization, KF was phosphorylated by a reactive phosphorus- and nitrogen-containing flame retardant for enhanced fire safety. The flame retardant was first synthesized by the reaction of urea and diethylene triamine pentakis (methyl phosphonic acid) (a commercially available scale inhibitor) with low cost, and then, applied in the phosphorylation of KF in the presence of dicyandiamide. In thermogravimetric analysis, phosphorylated KF showed 38.1% residue weight in nitrogen and 10.2% residue weight in air at 700°C, whereas the residue weight of KF was 8.4% in nitrogen and 1.5% in air. In microcalorimetric analysis, the heat release capacity and total heat release of phosphorylated KF displayed a reduction of 81% and 55%, respectively. In vertical combustion test, phosphorylated KF was difficult to ignite and had no afterburning or smoldering. The tests indicated that phosphorylated KF had excellent charring properties, low heat release, and good flame retardancy. This work suggests a promising strategy of enhancing the flame retardancy of KF and increasing its applicability in filling and composite materials. [ABSTRACT FROM AUTHOR]

The soft nap and deep pile that impart comfort and warmth to cotton fleece also amplify its flammability. Using ambient aqueous processing, an environmentally benign polyelectrolyte complex (PEC), consisting of poly(allylamine hydrochloride) and sodium hexametaphosphate, was deposited on cotton fleece. This treatment adds only 12.5% weight, reduces peak heat release by 68% and total heat release by 74%, and protects from fire via intumescence. Without treatment, fleece burns aggressively with long afterburn and afterglow times, leaving no residue. With the applied PEC, the fabric self-extinguishes within a few seconds and exhibits no afterglow. In addition, it withstands at least five simulated laundering cycles in alkaline detergent, maintaining a 57% reduction in fire growth capacity afterward. The original soft surface can be restored to the fleece by manual brushing. This simple and environmentally benign treatment provides an opportunity to effectively protect highly flammable textured cellulosic textiles in a safe way. [ABSTRACT FROM AUTHOR]

Epoxy resin was often applied in fiber-reinforced composite materials, adhesives, and encapsulation materials. However, epoxy was easily flammable and limited its usage in certain applications. The study recycled and reused agricultural waste sugarcane bagasse to prepare a halogen-free bio-based intumescent flame retardant and then mixed with epoxy resin to prepare a composite containing polymer with improved thermal properties and flame retardancy of the materials. The work followed the concept of circular economy and sustainability. Bagasse-ammonium dihydrogen phosphate (ADP) flame retardant was added to an epoxy resin to prepare epoxy/bagasse-ADP composites, an effective flame-retarding composite material through hydrothermal method. Adding bagasse-ADP increased the thermal stability and flame retardancy of the composite materials compared with that of pure epoxy. For the material with 30 wt % added bagasse-ADP, the char yield was 32.3 wt%, which was 18.2 wt% higher than that of pure epoxy (14.1 wt%) through thermogravimetric analysis. In addition, the limiting oxygen index increased from 21% to 30%, and the UL-94 classification improved from "Fail" to "V-0." This performance was attributed to the nitrogen, phosphorus, and silicon content of the flame retardant. [ABSTRACT FROM AUTHOR]

With a rapid expansion in applications of epoxy resins (EP) and derived composites, there is a high demand for improving their flame retardant and dielectric properties. In this work, a facile and convenient strategy for loading a dimethyl methylphosphonate (DMMP) flame retardant into the channels of ZIF-8 (zeolitic imidazolate framework) was developed, followed by the assembly of a hybrid ZIF-8@DMMP material with epoxy resin (EP). The obtained MOF-containing hybrid EP composites, abbreviated as 820/EP (with 20 wt% ZIF-8) and 8 FR20/EP (with 20wt% ZIF-8@DMMP), were fully characterized and shown to feature superior flame retardant behavior, contributing to an enhanced safety of such material in terms of total smoke suppression, lower levels of total heat release and carbon monoxide generation. The results demonstrated that the formation of an intumescent dense char layer restrained further combustion, thus enabling this composite material to feature a better flame retardant performance. Besides, the composite exhibited a dielectric permittivity and dielectric loss of as low as 3.0 at a high frequency, which significantly outperforms the neat epoxy resin. This work thus showcases a simple and efficient route to enhance dielectric and flame retardant properties of polymeric epoxy resins, while merging the inherent porosity of ZIF-8 and traditional flame retardant behavior of DMMP. [ABSTRACT FROM AUTHOR]