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We have successfully constructed a machine learning framework to predict the important properties of MOF-loaded (metal–organic framework) polymer composites. Our classification models have obtained promising predictive performance. The analysis of feature importance has revealed the relationship between MOFs and the properties of polymer composites, guiding the research focus for MOF's application in the fire safety field. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of adding borosilicate residue (BS) as a flame retardant in polypropylene (PP) and natural fiber composites. The natural fibers used in this study come from the residue of the carpet industry, which is composed of PP and jute fibers (JT), while the PP used as the polymer matrix is postindustrial recycled material. The composites were produced by corotational twin‐screw extrusion and injection molding to obtain the test specimens. A coating process was carried out to add the water‐soluble fraction of BS to the surface of the compositions that did not receive it through incorporation during processing. To characterize the composites, flammability tests, thermogravimetric analysis (TGA), tensile strength test, and morphological analysis by scanning electron microscope (SEM) were performed. The addition of only 2 wt% BS content induces an increase in thermal stability of 32 and 109°C for composites with and without natural fibers, respectively. The addiction of 20 wt% BS elevates the elastic modulus up to 27% of the composites with and without natural fibers. The BS characterization indicates that it could be applied as a flame retardant when applied as coating methods using the water‐soluble fraction of BS, reducing the burning rate up to 92%. Flammability results are similar for formulations with and without natural fibers, indicating that the natural fibers did not influence the proposed flame retardant. The findings suggest that BS coating is a potential solution to improve the properties of natural fiber‐reinforced polymer composites while also promoting waste recycling. This approach produces composites with improved flammability, thermal stability, and mechanical properties, making them suitable for various end applications. [ABSTRACT FROM AUTHOR]

Fireproof sealant is a common sealing material and has a wide range of applications, which has the dual performance of sealing and fireproof. To figure out its thermal degradation behavior, the thermogravimetric experiments combined with Fourier transform infrared technology were conducted at multiple heating rates. The results showed that the pyrolysis process could be separated into three stages and the explicit reaction equations were revealed corresponding to each stage: First, ammonium polyphosphate decomposed to produce a large amount of inorganic acid, along with a small amount of ammonia and water. Then, a large amount of ammonia gas was produced from melamine decomposition, and the substrate including acrylic resin began to react. Furthermore, the remaining base materials and intermediate carbonized materials continued to be decomposed to produce large amounts of carbon dioxide, water and residue. The experimental results indicated that the various components of fireproof sealant could cooperate closely and played a synergistic role in flame retardant, which could be an important reference value for guiding the improvement of fire sealing materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel and simple scheme for loading aluminum hypophosphite on MOF derivatives. • The dual function of carboxymethyl cellulose: buffer and support layer. • The double-layer hollow nano hybrid is integrated with multiple flame retardant elements. • The flame retardancy of epoxy resin composites is significantly improved after the introduction of AHP/ACP@CMC due to its unique components and nanostructure. Aluminum hypophosphite (AHP) has been used as a flame retardant for a long time. Previous studies about AHP employed in flame retardant materials mostly focus on coating, modification, and complex system. It is valuable to explore simple experimental steps to prepare nano hybrids with AHP and metal–organic frameworks (MOFs). We found acidic substances could etch zeolitic imidazolate framework-67 (ZIF-67) to obtain MOF derivatives. Unfortunately, AHP and ZIF-67 could not directly form a hybrid. Therefore, carboxymethylcellulose (CMC) is introduced as a dual function layer (buffer and support). The CMC resists the complete conversion of ZIF-67 etched by phosphoric acid to amorphous cobalt phosphate hydrate (ACP). Meanwhile, CMC containing hydroxyl groups combines with AHP through electrostatic interaction and coordination bonds. A double-layer hollow MOF derivative is synthesized through this one-stone-two-birds strategy. Due to multiple flame retardant elements and unique nanostructure, this MOF derivative endows epoxy (EP) resin with excellent flame retardancy. With 2.0 wt% addition, the peak heat release rate (pHRR) and total heat release (THR) of EP/AHP/ACP@CMC are decreased by 47.8 and 21.0 %, respectively. This study proposes a novel scheme that converts AHP into MOF derivatives as high-performance FRs. [ABSTRACT FROM AUTHOR]

High‐performance, versatile epoxy resins (EPs) are used in a variety of fields, but the manufacture of transparent, fireproof, and strong EPs remains a major challenge. The hyperbranched, multifunctional flame retardant (DSi) is prepared by using diethanolamine, polyformaldehyde, diphenylphosphine oxide, and phenyltrimethoxysilane as raw materials in this work. When the additional amount of DSi is only 2 wt.%, the EP‐DSi2 sample reaches a vertical burning (UL‐94) V‐0, and its limiting oxygen index (LOI) is 32.8%. When the content of DSi is 3 wt.%, the peak heat release rate (PHRR) and total smoke production (TSP) of EP‐DSi samples are 43.8% and 21.4% lower than those of EP. The good compatibility of DSi and EP endows EP‐DSi with high transparency, and the hyperbranched structure of DSi makes EP‐DSi have obviously enhanced mechanical strength and toughness. The enhanced fire safety of EP‐DSi is mainly due to the promoting carbonization and radical quenching effects of DSi. This paper offers a comprehensive design concept aimed at creating high‐performance epoxy resins with good optical, mechanical, and flame‐retardant properties, which have broad application prospects. [ABSTRACT FROM AUTHOR]

With a growing focus on sustainable building thermal regulation for buildings, cellulose foams have emerged as promising materials due to their low thermal conductivity and biodegradable properties. However, their flammability and hygroscopic nature limit practical applications. This is attributed to the abundant hydroxy groups of cellulose. In this study, a sustainable, simple, and cost-effective method was proposed for the synthesis of multifunctional thermal insulation materials based on cellulose nanofiber composite foam with hydrophobic, flame retardant, and thermally insulating performance. As a result, the cellulose nanofiber composite foam showed a high mechanical modulus (6.3 ± 0.3 MPa), high compression strength (0.78 ± 0.10 MPa), and specific modulus (246.2 ± 34.4 MPa·cm3·g⁻1). The homogeneous three-dimensional (3D) porous network structure of cellulose nanofiber composite foam resulted in outstanding thermal insulation capabilities (LOI values of 60.7 ± 3.2, UL-94 V-0 rating) and low thermal conductivity (36.3 ± 0.8 mW·m⁻1 K⁻1). Furthermore, the incorporation of phytic acid (PA) imparted high flame retardancy, while cellulose nanofiber composite foam modified with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (POTS) maintained outstanding hydrophobicity (static water contact angle of 145.5° ± 0.2°) even under harsh environmental conditions. In this way, it is believed that cellulose nanofiber composite foam with light weight, high mechanical strength, thermal insulation, high flame retardancy, and hydrophobicity has great potential in thermal insulation materials. [ABSTRACT FROM AUTHOR]

A new strategy for multifunctional coatings with flame retardancy, superhydrophobicity and UV shielding ability on cotton fabrics (SFR cotton) was realized by step-by-step spraying ammonium phytate, lignin and hybrid nanoparticles of polydimethylsiloxane (PDMS) modified mesoporous silica nanoparticles (MSNs) with entrapped Fe2O3 (PDMS@Fe2O3-MSNs). The surface adhesion PDMS@Fe2O3-MSNs constructed micro/nano-scale surface structure on SFR cotton fabric, which endowed superhydrophobic (WCA = 152 ± 1.3°), anti-fouling and self-cleaning properties. Benefiting from the synergistic effects of the physical barrier provided by the PDMS@Fe2O3-MSNs and the intumescent flame-retardant properties of ammonium phytate and lignin, the SFR cotton fabric demonstrated excellent self-extinguishing performance under an open fire and left a char layer with 8.4 cm. In addition, due to the excellent UV-absorption ability of lignin and Fe2O3 nanoparticles, the SFR cotton fabric was able to shield the UV irradiation damages to rat skin. Furthermore, the SFR cotton fabric demonstrated remarkable durability against rigorous conditions, including ultrasonic washing, sandpaper abrasion, UV irradiation and exposure to strong acid/alkali environments. After 150 min of ultrasonic washing and 50 cycles of abrasion, the SFR cotton fabric could preserve its hydrophobicity, flame retardancy and UV shielding ability. In addition, the SFR cotton fabric delivered exceptional chemical stability and UV durability when exposed to strong acid/alkali for 24 h and UV irradiation (200 W) for 12 h, respectively. Significantly, the SFR cotton fabric could retain the original flexibility and breathability of pristine cotton fabric. Therefore, the simple and feasible strategy of multifunctional coatings has broad application prospects in advanced multifunctional textiles, military facilities and other fields. [ABSTRACT FROM AUTHOR]

Green chemicals and their applications to textiles became popular for imparting specific functional properties. Because of their complicated applications, the production of multifunctional textiles consumes high energy and produces high amount of wastewater. Therefore, in this study, an innovative one-step approach was used in order to obtain multifunctional cotton fabrics. Montmorillonite/Ionic Liquid (MMT-IL) nanocomposites were formed by using 3 different ionic liquids [IL1 (1-Methyl-3-butylimidazolium chloride, IL2 (1-Methyl-3- octylimidazolium tetrafluoroborate), and IL3 (1-Methyl-3-octylimidazolium bromide)], at 3 different concentrations determined which were based on the cation exchange capacity (CEC) of the montmorillonite clay mineral and MMT-IL nanocomposites. The synthesized MMT-IL nanocomposites were applied to the cotton fabrics by pad-dry-cure method. The pad-dry-cure process was carried out on fabrics also by using 2 different crosslinkers. Modified ethylene urea (MDEU) and (3-Chloropropyl)trimethoxylane (CPTES) were used as crosslinkers. Structural, thermal and surface properties of the MMT-IL nanocomposites and the treated fabrics were determined by FTIR, XRD, TGA, and SEM–EDS analyses. The performance properties of untreated and MMT-IL nanocomposite-modified fabrics were investigated. In order to determine multifunctional properties, antimicrobial, flame retardancy and conductivity values were examined according to the standards. In addition, whiteness index values were also measured to determine whether the MMT-IL nanocomposite modification affected the appearance properties of the fabrics. The performance properties of the fabrics were detailed by using the Box-Behnken experimental design. This paper describes the synthesis and application of Ionic Liquid-Clay Nanocomposites to cotton fabrics. The IL-MMT treated fabrics gained antimicrobial, flame retardant, and conductive properties. [ABSTRACT FROM AUTHOR]

The flammability of unsaturated polyester resins (UPRs) limits their applications. Herein, a reactive P‐ and N‐containing flame retardant (DPET) having triazole and piperazine rings is reported. The 9,10‐Dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) was used to introduce P atoms, and eugenol was used to import reactive double bonds to DPET. Different ratios of DPET were mixed with a commercial UPR and the thermal, mechanical, optical, and flame retardancy properties were measured. The addition of 15% of DPET into neat UPR led to a decrease in the water contact angle from 70° ± 2 to 61° ± 2. The gel content values of the UPRs were found to change between 97.5% and 89%. The optical properties of the UPR were adversely affected by the incorporation of DPET. The modulus of the DPET‐containing UPRs increased with increasing amount of DPET and 15% of DPET‐containing UPR displayed a modulus value of 1784 ± 86 MPa. When 15% DPET was added to neat UPR, char yields were increased (from 5.6% to 16.6%). Limiting oxygen index (LOI) values increased with increasing amounts of DPET and reached up to 23.4%. Micro cone calorimeter (MCC) test results showed up to a 20.5% reduction in the peak heat release rate (PHRR) of the UPR when 15% DPET was added. [ABSTRACT FROM AUTHOR]

Organophosphorus compounds have been widely used as achiral and chiral ligands in organic synthesis (PPh3, BINAP, dppe, Duphos, Xantphos, PPFA, Chiraphos, SEGPHOS), flame retardants, functional materials (LED, PV), as well as agrochemicals and medicines due to their broad biological activities. As the privileged versatile building blocks, 1,n‐enynes have been successfully applied in the synthesis of various functionalized cyclic compounds based on their two active unsaturated chemical bonds (C═C double and C≡C triple bonds). With the development of highly selective and efficient methods in organic chemistry, various organophosphorus cyclic compounds synthesis through radical cascade strategy has attracted considerable attention in recent years. In here, we have summarized the recent main achievements in the radical cascade reactions of 1,n‐enynes with phosphorus‐centered radicals. Furthermore, we also displayed the detailed reaction mechanisms in this review. [ABSTRACT FROM AUTHOR]

The construction of poly‐dioxolane (PDOL) solid‐state electrolytes by in situ polymerization is an effective way to achieve high performance lithium‐metal batteries. However, the poor electrochemical stability and safety issues of linear PDOL limit their further application. In this work, a multifunctional crosslinker has been introduced to construct a flame retardant crosslinked quasi solid‐state electrolyte (FCDOL). Due to the synergistic effect of the crosslinked network, the prepared FCDOL achieves excellent room temperature ionic conductivity (0.72 mS cm−1), high Li+ transference number (0.655), wide electrochemical stabilization window (4.8 V vs Li/Li+), and impressive performance when matched with lithium metal anodes (>4000 h plating/stripping) and high‐voltage cathodes, and the corresponding pouch cells can withstand abusive tests such as bending and cutting, encouraging that in situ polymerization of SPEs provides new insights into high‐energy density and high‐safety solid‐state batteries. [ABSTRACT FROM AUTHOR]

The use of materials from renewable sources instead of fossil fuels is a crucial step forward in the industrial transition toward sustainability. Among polysaccharides, alginate stands out as a versatile and eco‐friendly candidate due to its ability to form functional complexes with cations. This review provides an up‐to‐date and comprehensive description of alginate complexation with specific cations, focusing on how interaction forces can be harnessed to tailor the physicochemical properties of cation‐alginate‐based functional materials. Methodologies and approaches for the development and multiscale characterization of these materials are introduced and discussed. Alginate complexes with mono‐, di‐, tri‐, and tetravalent cations (namely Ag+, Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Cr3+, Fe3+, Al3+, Ga3+, Y3+, La3+, Ce3+, Nd3+, Eu3+, Tb3+, Gd3+, Zr4+, Th4+) are reviewed. Each cation is discussed individually, highlighting how it can uniquely influence the material properties thereby unlocking new potentials for the design of advanced functional materials. Key challenges and opportunities in applying these complexes across diverse fields, such as biomedicine, environmental remediation, food additives and supplements, flame retardants, sensors, supercapacitors, catalysis, and mechanical isolators are assessed, providing evidence of the transformative potential of cation‐alginate complexes for tackling global challenges and advancing cutting‐edge technologies. [ABSTRACT FROM AUTHOR]

Although many researchers continue to pursue improved battery capacity, battery safety remains a major concern. The main cause of battery fires is the flammability of the currently available commercial organic liquid electrolytes, which are mainly composed of 1 M lithium hexafluorophosphate (LiPF6) and EC-containing carbonate solvents. Herein, a flame-retardant co-solvent tris(2,2,2-trifluoroethyl) phosphite (TTFP) was applied to improve the flame retardancy of a battery. It could improve the battery's discharging capacities at both 4.2 V and high cut-off voltage (4.5 V). Specifically, at a common voltage of 4.2 V, the cells' 100th discharge capacity without TTFP was 130 mA h g−1 by 0.2C with a capacity retention (CR) of 69%. In comparison, under the same conditions, the capacity of the 10% TTFP-containing cell was 162.3 mA h g−1 with a CR of 73.9%. This increase in the electrochemical properties of the cell is clearly due to the addition of TTFP. When charging and discharging at 2.75–4.5 V, the capacity of the battery with STD after 100 cycles at 0.2C was 118.7 mA h g−1, and the corresponding CR was 60.93%. Meanwhile, the discharged capacity of the battery containing 10% TTFP was 150.0 mA h g−1 with a corresponding CR of 65.39%. Through combustion test with and without the TTFP electrolyte, it can be concluded that the TTFP-containing electrolyte is difficult to ignite. This result indicates that TTFP can efficiently enhance the safety performance of the battery. Thus, the incorporation of TTFP can be beneficial to improve the flame retardancy of the electrolyte. Moreover, TTFP does not affect the electrochemical stability of batteries. Thus, the present work may provide a good direction for the next generation of high-performance and high-safety lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Organic flame retardant 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) was used to decorate the pores of mesoporous silica (m‐SiO2) nanospheres to prepare a new composite flame retardant (DK‐SiO2). The content of DOPO in DK‐SiO2 is about 17 wt%. Due to the chemical bonding, DK‐SiO2 not only enhances the flame retardant performance, but also effectively avoids adverse effects of DOPO on the glass transition temperature and mechanical properties of epoxy resin (EP). At 9 wt% loading, the limiting oxygen index of the EP increased from 25.7 to 31.2, and successfully passed the UL‐94 V‐0 rating. Besides, DK‐SiO2 can significantly reduce the peak heat release rate, total heat release, and total smoke production of EP, with reductions of 26%, 32%, and 20.8%, respectively. Compared with the simple blended sample, DK‐SiO2 not only has better flame retardant performance but also shows significant advantages in thermodynamic properties. The glass transition temperature, impact, and tensile strength, as well as storage and flexural modulus have been improved. This excellent flame retardant performance is mainly attributed to the gas‐condensed synergistic flame retardant mechanism between DOPO and m‐SiO2. The good thermodynamic performance is due to the excellent dispersion of DK‐SiO2 nanospheres in the EP. [ABSTRACT FROM AUTHOR]

Balancing the enhancement of flame retardancy of epoxy resin while maintaining its mechanical capacities intact poses a significant challenge in the realm of flame‐retardant epoxy resins. To reach the above objectives, a COF‐based synergistic flame retardant with phosphorus, nitrogen, and silicon (PA‐COF@MT) was synthesized using phytic acid (PA), montmorillonite (MT), and covalent organic framework (COF). When PA‐COF@MT was added at 4 wt%, EP/PA‐COF@MT exhibited a reduction of 42.1% in peak heat release rate (PHRR), 45.84% in total heat release (THR), and 59.8% in total smoke production (TSP) compared with the pure EP. LOI increased by 30.5% and UL‐94 tested to V‐0 grade. flame‐retardant index (FRI) value of 3.03, achieving a "good" rating. Fire growth indices and mean effective combustion heat were increased while mechanical properties also improved. These findings suggest that the flame retarding mechanism of PA‐COF@MT is mainly through vapor phase and condensed phase actions. The combined effects of phosphorus, nitrogen, and silicon make the surface of carbon residue solid and dense, resulting in excellent heat insulation and smoke suppression effects. In simple terms, this study provides new insights into COF‐based flame retardants. Combining low‐cost and simple preparation methods, PA‐COF@MT has broad application prospects in flame‐retardant epoxy resin systems. [ABSTRACT FROM AUTHOR]

In order to improve the flame retardancy and smoke suppression of silicone rubber foam (SRF), the CoFe‐LDH was fabricated by coprecipitation method and used as flame‐retardant ingredient in SRF. The influence of CoFe‐LDH on the flame retardancy, combustion behavior, and thermal stability of SRF was investigated. The results demonstrate that SRF containing only 1.0 phr CoFe‐LDH can pass V‐0 rating in the vertical combustion test, with a limiting oxygen index of 28.6%. The total heat release and total smoke production are 22.2% and 61.1% lower than that of SRF, respectively. Moreover, CoFe‐LDH can improve the thermal stability of SRF in the high temperature range, and the char residue at 900°C of SRF/LDH composite is obviously higher than that of pure SRF. In addition, to further understand the flame‐retardant mechanism of CoFe‐LDH, the micromorphology of the char residue and the gaseous products during heating for SRF and SRF/LDH composite were analyzed. The results indicate that CoFe‐LDH exhibits excellent flame‐retardant effects in both condensed and gaseous phases for its functions of catalysis, carbonization, and nonflammable gas release. This study provides a more efficient and convenient strategy for the flame retardant and smoke suppression research of SRF. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants (POPs) are environmental contaminants that can accumulate in human tissues and pose potential health risks. Despite global efforts to reduce their prevalence, follow‐up studies are needed to see if the measures are successful. Since most infants in Norway are breastfed for the first 6 months of life, monitoring POP contamination in breastmilk is important for children's health and development. This study aims to evaluate the current levels of various POPs in women's breastmilk in Innlandet County, Norway. A cross‐sectional study was conducted measuring concentrations of 35 different POPs, including polychlorinated biphenyls (PCBs), chlordanes (ChlDs), hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), Mirex, and brominated flame retardants in 120 breastmilk samples. The study analysed the impact of maternal age, parity, pre‐pregnancy BMI, and infant age on POPs levels and compared the estimated daily intake per body weight of infants to existing health guidelines. The detected percentages for PCBs were 100%, for DDTs 98.3%, and for ChlDs 98.3%. The highest median concentration was found for ΣPCBs (26.9 ng/g lw). Maternal age, parity, and infant age were significant determinants of POP concentrations. Most infants exceeded the health‐based guidance values for ΣPCB, and 6.4% percent did so for ΣHCHs. Despite lower POPs concentrations in breastmilk than in earlier studies, many breastfed infants are still exposed to levels exceeding health‐based guidance values. Although the study's design had limitations, the study provides updated population‐based data on POPs in breastmilk. Continued monitoring and research are necessary to understand and mitigate potential health risks associated with POPs. [ABSTRACT FROM AUTHOR]

In order to achieve flame retardant, hydrophobic, and toughened epoxy resins, phosphorus/fluorine‐containing block copolymer (FBCP) was synthesized by reversible addition‐fragmentation chain transfer polymerization, and then the as‐synthesized PMADOPO‐b‐PHFBA block copolymer was used as additive to modify the epoxy resin, accompanying with a random copolymer (FRCP) serving as control group. It showed that due to the regular arrangement of molecular chains, FBPC formed a fibrous‐like structure at the fracture interface of epoxy/PMADOPO‐b‐PHFBA (EP/FBCP) samples, effectively enhancing the toughness of epoxy composite materials. The fracture energy of EP90/FBCP‐10 was higher than that of EP90/FRCP‐10 and was about twice than that of pure EP. The addition of 3 wt% FBCP could enhance the limited oxygen index (LOI) of EP97/FBCP‐3 to 33.2% and reached a V‐1 UL‐94 rating. As the addition of FBCP increased, the LOI gradually increased. When the addition of FBCP was 10%, the LOI and UL‐94 of EP90/FBCP‐10 was 38.2% and V‐0 grade, respectively. Meanwhile, the presence of fluorine element effectively reduced the surface energy of the composite EP material. Compared with pure EP, the water contact angle of EP90/FBCP‐10 was about 101° with an increasing of 20.8%. Furthermore, the flame‐retardant mechanism of EP/FBCP epoxy composites was discussed. [ABSTRACT FROM AUTHOR]

As the application of polycarbonate (PC) in various fields continues to expand, the requirements for its flame retardancy are becoming increasingly stringent. To enhance the flame retardancy of PC, employing multi‐element synergistic effects and developing novel flame retardants are considered as vital strategies. This work introduces a blend of 1,3‐Benzenedisulfonic acid dipotassium salt (KSP) and three types of phenyl polysiloxanes, namely Octaphenylcyclotetrasiloxane (P4), Octaphenylsilsesquioxane (OPS), and ladder‐like Polyphenylsesquioxane (L‐PPSQ), into PC to create composites. The thermal stability and combustion properties of these composites were characterized using thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL‐94 vertical burning, and cone calorimetry tests. Composites with phenyl polysiloxanes achieved a UL‐94 V‐0 flame retardant rating for 1.6 mm thickness sample and reduced the peak heat release rate by 30%–45%. PC composites with 3% OPS and 0.03% KSP achieved optimal performance, howing a LOI of 34.5%, a 45.4% reduction in peak heat release, and a 40.5% reduction in total smoke release. The flame‐retardant mechanism was analyzed using scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and pyrolysis‐gas chromatography‐mass spectrometry (Py‐GC‐MS). [ABSTRACT FROM AUTHOR]

Halogen‐free flame‐retardant ethylene‐vinyl acetate/polyethylene/magnesium hydroxide systems are widely used in cable insulations and in sheath materials. The surface modification of magnesium hydroxide is one of the key methods to improve its dispersion and mechanical properties. The effects of different types of interfaces, formed by four surface modifications, namely KH550, KH570, stearic acid, and titanate, on the flame retardancy of composite systems have been investigated in the present study. The results showed that the four surface modifiers formed chemical bonds with the surface of magnesium hydroxide, which promoted the dispersion of particles in the matrix. However, due to the different effects of the various surface modifiers and polymer molecular chains, the interfaces exhibited different chemical structures and physical strengths, which affected the combustion of the composite materials into carbon. Thus, the composites demonstrated different flame‐retardant properties. The surface modifiers KH550, KH570 and titanate can form chemical bonds with the ethylene‐vinyl acetate (EVA) copolymer and have, thereby, a strong effect on the interfaces, which resulted in a slow ignition of the materials and the formation of a graphite carbon structure that is advantageous for heat transfer and oxygen insulation. This is conducive to the flame‐retardant performance of the composite systems. [ABSTRACT FROM AUTHOR]

To enhance the flame‐retardant characteristics of ceramifiable polyethylene (PE) composites, a composite flame retardant comprising ammonium polyphosphate (APP) and melamine cyanurate (MCA) was integrated. This addition markedly bolstered their flame‐retardant attributes. A meticulous exploration was conducted to ascertain the impacts of APP and MCA on the ceramifiable PE composites' visible morphology, mechanical robustness, and dimensional constancy, and to study the phase transition and microstructure deformation during sintering. Findings underscored that the amalgamation of APP/MCA markedly enhanced the flame resistance of these ceramifiable composites, registering a limiting oxygen index of 25.6% and achieving the vertical burning test (UL‐94) rating of V‐0. The collaborative flame‐retardant action of APP/MCA significantly enhanced the flame resistance of the PE composites while effectively mitigating the composite's propensity to drip. Upon detailed phase analysis, a eutectic reaction was observed between APP and wollastonite fiber, culminating in the genesis of a novel crystalline phase, calcium pyrophosphate (Ca2P2O7). When subjected to elevated temperatures, glass–ceramics manifest with both crystalline and vitreous phases. The proportion of the vitreous phase plays a pivotal role in influencing the ceramic's overall performance. [ABSTRACT FROM AUTHOR]

C-H activation is a powerful strategy for forming C-C bonds without the need for prefunctionalization. In this paper, we present a general, direct, and regioselective palladium-catalyzed functionalization of a phosphorus heterocycle, 2-phenyl-1H-isophosphinoline 2-oxide. The mild reaction conditions enabled the introduction of various functionalized alkenes. Moreover, the flame-retardant properties of selected products clearly highlighted the synergy between the phosphine oxide and another heteroatom-based group, even in the condensed phase. [ABSTRACT FROM AUTHOR]

The growing volume of plastics derived from electronic waste (e-waste) underscores the imperative for environmentally sustainable strategies for the management of this waste. In light of the paramount importance of this issue, a pilot demonstrator for the decontamination of polymers containing Brominated Flame Retardants (BFRs) has been developed. The objective is to investigate the potential for decontaminating BFR-containing polymers from e-waste via UV-visible irradiation using a rotatory laboratory pilot operating under primary vacuum conditions. This report focuses on binary model blends composed of 90 weight% (wt%) poly(Acrylo-Butadiene-Styrene) (ABS) pellets and 10 wt% Deca-Bromo-Diphenyl Ether (DBDE), which is one of the most toxic BFRs. The efficiency of the irradiation process was evaluated as a function of pellet diameter and irradiation time using Fourier Transform InfraRed spectroscopy (FTIR) and High-Resolution Laser Desorption/Ionization Mass Spectroscopy (HR-LDI-MS). As a consequence, ABS + DBDE achieved a decontamination efficiency of 97% when irradiated with pellets of less than 1 mm in diameter for a period of 4 h. Additionally, the thermal behavior of the irradiated samples was investigated through thermogravimetric analysis and differential scanning calorimetry. It was thus established that the application of UV-visible irradiation had no significant impact on the overall thermal properties of ABS. [ABSTRACT FROM AUTHOR]

Epoxy resins (EPs) are highly flammable, and traditional flame retardant modifications often lead to a significant reduction in their mechanical performance, limiting their applications in aerospace and electrical and electronic fields. In this study, a novel flame retardant, bis(4-(((diphenylphosphoryl)oxy)methyl)phenyl)phenyl phosphate (DMP), was successfully prepared and introduced into the EP matrix. When the addition of DMP was 9 wt%, the EP/9 wt% DMP thermosets passed the UL-94 V-0 rating, and their LOI was increased from 24.5% of EP to 35.0%. With the introduction of DMP, the phosphoric acid compounds from the decomposition of DMP promoted the dehydration and charring of the EP matrix, and the compact, dense char layer effectively exerted the shielding effect in the condensed phase. Meanwhile, the produced phosphorus-containing radicals played a quenching effect in the gas phase. As a result, the peak heat release rate (PHRR) and total heat release (THR) of EP/9 wt% DMP were reduced by 68.9% and 18.1% compared to pure EP. In addition, the polyaromatic structure of DMP had good compatibility with the EP matrix, and the tensile strength, flexural strength and impact strength of EP/9 wt% DMP were enhanced by 116.38%, 17.84% and 59.11% in comparison with that of pure EP. This study is valuable for expanding the application of flame-retardant EP/DMP thermosets in emerging fields. [ABSTRACT FROM AUTHOR]

Wood modification has been explored in various ways to enhance dimensional stability and reduce flammability, with a focus on environmentally friendly treatments to meet market demands. This study aimed to investigate the efficacy of new, potential fire-retardant materials. Specifically, the study examined the combination of tripotassium citrate (TPC), a water-soluble and bio-based fire retardant, with sorbitol and citric acid (SorCA), an eco-friendly thermosetting resin previously studied. While TPC is known to control combustion, its application in wood modification has not been thoroughly researched. To assess the fixation and flammability of these fire retardants, tests were conducted on Scots Pine (Pinus sylvestris L.), including chemical analysis, dimensional stability, mechanical properties, flame retardancy, and leaching tests. The combination of SorCA and TPC showed high weight percent gain (WPG) values; however, leaching and anti-swelling efficiency (ASE) tests revealed challenges in fixation stability. The dynamic mechanical properties were reduced, whereas the static strength values were in the same range compared with untreated wood. While TPC exhibited high flame retardancy prior to leaching, its efficacy diminished post-leaching, underscoring challenges in fixation and the need for improved retention strategies. Bunsen burner tests conducted on leached specimens indicated enhanced performance even under severe leaching conditions as per the EN 84:2020 procedure. However, cone calorimetry measurements showed less favorable outcomes, emphasizing the necessity for further investigation into optimizing TPC retention and enhancing treatment efficacy. [ABSTRACT FROM AUTHOR]

Currently, postulated trends and law regulations tend to direct polymer technology toward sustainability and environmentally friendly solutions. These approaches are expressed by keeping materials in a loop aimed at the circular economy and by reducing the environmental burdens related to the production and use of polymers and polymer-based materials. The application of recycled or waste-based materials often deals efficiently with the first issue but at the expense of the final products' performance, which requires various additives, often synthetic and petroleum-based, with limited sustainability. Therefore, a significant portion of research is often required to address the drawbacks induced by the application of secondary raw materials. Herein, the presented study aimed to investigate the fire performance of polymer composites containing highly flammable matrix polyurethane (PU) foam and filler ground tire rubber (GTR) originating from car tire recycling. Due to the nature of both phases and potential applications in the construction and building or automotive sectors, the flammability of these composites should be reduced. Nevertheless, this issue has hardly been analyzed in literature and dominantly in our previous works. Herein, the presented work provided the next step and investigated the input of nanoclays to the synergistic flammability reduction in flexible, foamed PU/GTR composites. Hybrid compositions of organophosphorus FRs with expandable graphite (EG) in varying proportions and with the addition of surface-modified nanoclays were examined. Changes in the parameters obtained during cone calorimeter tests were determined, discussed, and evaluated with the fire performance index and flame retardancy index, two parameters whose goal is to quantify the overall fire performance of polymer-based materials. [ABSTRACT FROM AUTHOR]

An effective type of polymer heat-insulating material (foams) based on reactive oligomers is casting epoxy foams with high technological and operational parameters. However, polyepoxide foams are highly flammable, which significantly restrains their application in the construction industry. The aim of this work was to develop effective methods for reducing the flammability of filling epoxy foams. In order to achieve the objective, the following objectives were addressed: determining the influence of the chemical nature and content of additive and reactive bromine- and phosphorus-containing compounds on the thermal stability, flammability and operational properties of filling epoxy foams, and the development of polyepoxy foams of reduced flammability with high-quality physical and mechanical characteristics. When estimating the flammability of epoxy foams, we used both state-approved methods and the methods described in scientific and technical literature. The thermal properties of epoxy foams were studied with the help of multimodular thermoanalytical complex DuPont-9900. The data on the influence of the apparent density of foams and oxygen concentration in the oxidant flow on the flame propagation speed on the horizontal surface of polyepoxy foams are presented. It was revealed that the chemical nature of amine hardeners does not affect the thermal stability and flammability of epoxy foams. It was established that phosphate plasticizers are ineffective flame retardants of foamed epoxy resin, and the chemical structure of additive organobromic flame retardants insignificantly affects their efficiency. It was shown that microencapsulated flame retardants are inferior in flame retardant efficiency to additive flame retardants. It was found that effective flame retardants for casting polyepoxy foams are phosphorus-containing oligoether methacrylate and epoxidized waste from the production of tetrabromodiphenylpropane. The results of this research will form the basis for the production of an experimental industrial batch of samples of pouring epoxy foams of reduced flammability. [ABSTRACT FROM AUTHOR]

This work focuses on the changes in the chemical composition of wood caused by impregnation with fire retardants such as guanidine carbonate (GC), urea (U), diammonium phosphate (DAP) and their mixtures. The treated wood was tested using the oxygen index (LOI), Py–GC/MS analysis and FTIR Spectroscopy. The wood was vacuum treated at a pressure of 0.8 MPa for 20 min and then subjected to thermal degradation using the LOI. This way, degraded and nondegraded layers were obtained and ground (0.2 mm). All treatment variants achieved the class of non-flammable materials based on LOI tests; the exception was the 5% urea solution, defined as a flame-retardant material. Using the analytical methods, it was found that cellulose and hemicelluloses undergo the fastest thermal degradation. This study found that the variant protected with a 5% mixture of GC and DAP before and after the degradation process had the best fire-retardant properties regarding cellulose content in the wood. The highest content of anhydrosugars characterised the same variants, the amount of which indicates a slowdown in the degradation process and, consequently, a reduction in the release of levoglucosan during combustion, suggesting potential applications in fire safety. [ABSTRACT FROM AUTHOR]

To determine the thermal kinetic triplets and elucidate the reaction mechanism of thin intumescent fire-retardant coatings (IFR) of steel structures, one efficient combined kinetic approach was implemented in this study. Thermogravimetric experiments were conducted in air atmosphere at four heating rates, and the whole IFR thermal degradation process was divided into two stages. The average activation energy values derived by model-free methods were 78.9 kJ/mol and 175.16 kJ/mol for Stage I (0<α < 0.2) and Stage II (0.2<α < 0.9), respectively. Furthermore, the linear Coats-Redfern (CR) and non-linear Masterplots models were applied to identify the possible reaction mechanism. It was found that the F3/2 mechanistic model was better suited to the main thermal degradation process. Then model reconstruction based on the F3/2 mechanism model was performed. The results showed that the reconstructed model had a strict linear relationship in the independence analysis and KCE analysis, along with a good agreement between the theoretical and experimental results. The current study provided new insights into the systematic thermal degradation mechanism of IFR, and the proposed kinetic model would be helpful for the thermal protection prediction for steel structure during fire. [ABSTRACT FROM AUTHOR]

Over traditional flame retardants, the hybrid material technology of flame retardant combines separate constituents into an entirety, demonstrating the benefit of the simultaneous development in polymer flame retardant. Zinc-layered hydroxide, borate, and thermoplastic polyurethane were used to create LZH/B/TU, a new organic-inorganic composite flame retardant. The structure of LZH, LZH/B, and LZH/B/TU was studied after synthesis with analysis spectroscopy. The borate ion was effectively intercalated into the interlayer space of the LZH, according to the XRD and FTIR studies. Using EDS analysis, the chemical makeup of the materials was assessed. The morphology of the synthesized product was identified using FESEM. The dynamic mechanical thermal (DMT) properties of the optimum sample were evaluated with DMTA analysis. The fire risk of epoxy resin was considerably reduced by using a small amount of LZH/B/TU. According to the flammability test and plate temperature experiment, LZH/B/TU with 1% w/w led to the creation of the char layer's capacity to insulate heat with strong thermal resistance, resulting in dramatically reduced fire hazards. [ABSTRACT FROM AUTHOR]

9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-N-Aminoethylpiperazine (DOPO-AEP), a phosphorus and nitrogen intumescent flame retardant curing agent was prepared by using acetonitrile as solvent using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and N-aminoethylpiperazine (AEP) as raw materials. The structure of the flame retardant curing agent DOPO-AEP was analyzed Fourier Transform Infrared Spectrometer (FTIR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESI-MS), and the synthesis method of the target product was determined. In addition, the content of char residue was determined by thermogravimetric analyzer, and its thermal properties were comprehensively explored, and based on the obtained results, the curable epoxy resin was selected to prepare DOPO-AEP/EP flame retardant composites. According to the amount of DOPO-AEP added product, different proportions of DOPO-AEP/EP flame retardant composites were prepared, and the actual impact of flame retardant properties and mechanical properties of epoxy resin in different proportions was explored. When the content of DOPO-AEP is 35%, the limiting oxygen index of DOPO-AEP/EP reaches 29.9, which has a significant increase compared with the limiting oxygen index of pure epoxy resin of 19.8, but compared with the content of DOPO-AEP of 30%, the limiting oxygen index of DOPO-AEP/EP is 28.7, and there is no significant increase change. Comprehensive analysis shows that when the component content of DOPO-AEP is 30%, the flame retardant system has a tensile strength of 29.0 MPa, an impact strength of 4.5Kj/m2 and a flexural strength of 73.9 MPa, and its limiting oxygen index is as high as 28.7, and the comprehensive performance of the system is the best. By testing the surface morphology of the flame retardant composites after combustion by SEM, it was found that a dense char layer was formed on the surface of the epoxy resin cured char residue and foamed obviously, indicating that the flame retardant curing performance of DOPO-AEP was good. [ABSTRACT FROM AUTHOR]

Despite the fact that environmental pollution has been implicated in the global rise of diabetes, the research on the impact of emerging pollutants such as novel flame retardants remains limited. In line with the shift towards the use of non-animal approaches in toxicological testing, this study aimed to investigate the effects of two novel flame retardants tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPhP) in rat (INS1E) and human (NES2Y) pancreatic beta-cell lines. One-week exposure to 1 μM and 10 μM TDCIPP and TPhP altered intracellular insulin and proinsulin levels, but not the levels of secreted insulin (despite the presence of a statistically insignificant trend). The exposures also altered the protein expression of several factors involved in beta-cell metabolic pathways and signaling, including ATP citrate lyase, isocitrate dehydrogenase 1, perilipins, glucose transporters, ER stress-related factors, and antioxidant enzymes. This study has brought new and valuable insights into the toxicity of TDCIPP and TPhP on beta-cell function and revealed alterations that might impact insulin secretion after more extended exposure. It also adds to the scarce studies using in vitro pancreatic beta-cells models in toxicological testing, thereby promoting the development of non-animal testing strategy for identifying pro-diabetic effects of chemical pollutants. [ABSTRACT FROM AUTHOR]

In this paper, a 150-µm-thick flexible γ-Al2O3 nanofiber separator with the tensile strength of 0.22 MPa was prepared from the low-cost aluminum chloride hydroxide/polyvinyl alcohol (PVA)/water precursor materials by electrospinning method. The resultant separator with 3D interconnection nanostructure revealed fiber diameters in the range of 200 to 500 nm. The specific surface area, porosity, and electrolyte uptake of γ-Al2O3 nanofiber separator are 31.5 m2/g, 55%, and 1021%, higher than that of commercial polypropylene (PP) separator and glass fiber (GF) separator. The supercapacitor assembled with the γ-Al2O3 nanofiber separator exhibited a high discharge specific capacitance of 93 F/g at the current density of 1A/g, and there is almost no capacity decay after 10,000 cycles. The energy density of supercapacitor assembled with γ-Al2O3 nanofiber separator is 31.7 Wh/kg at the power density of 562.6 W/kg. Meanwhile, the rate performance of the supercapacitor is improved significantly due to the existence of porous structure and low ion diffusion resistance (0.78 Ω) of γ-Al2O3 nanofiber separator. In addition, the thermal performance of the γ-Al2O3 nanofiber separator is also excellent, which has almost no shrinkage at the temperature of 200 °C and cannot be ignited. Therefore, the obtained γ-Al2O3 nanofibers could serve as a promising alternative separator for a new generation of safe, high-power supercapacitors. [ABSTRACT FROM AUTHOR]

The utilization of natural fibers obtained from leather industrial wastes contributes to a circular economy and aids to the reduction in the usually high loadings of mineral flame-retardant additives employed to impart the flame retardancy in polymer systems. The present work investigates the relationship between viscoelastic properties and flame retardancy of thermoplastic starch multicomponent systems loaded with leather waste, aluminum trihydroxide used as flame-retardant additive, and bentonite clay. Different blending temperatures and rotational speeds during extrusion process are tested for the multicomponent systems. Rheological, morphological, flammability, thermal analysis, and tensile mechanical test are also used to characterize the obtained multicomponent systems. A detailed investigation of the viscoelastic properties through Han, Cole–Cole, and van Gurp–Palmen diagrams indicated that the fibers have to be well dispersed in the polymer matrix forming a network structure and that the material has to exhibit viscoelasticity to a moderate level, i.e., not too viscous and not too elastic as observed in the VGP diagram in order to impart the flame retardancy effect in the multicomponent system. These multicomponent systems with enhanced properties are a promising and sustainable alternative to traditional high-loaded flame-retardant systems taking advantage of the landfill disposal in local areas where leather wastes are a problem the great attention contributing to a circular economy. [ABSTRACT FROM AUTHOR]

This study aims to create fire-resistant performance of polyurethane (PU)-coated textiles by adding wool powder as a flame retardant on both cotton and polyester fabrics. A flame-retardant surface was therefore developed by coating the fabrics with a mixture of PU and wool powder and characterised by using Fourier transform infrared spectroscopy and scanning electron microscopy. The experimental results demonstrated that with a coating thickness of 0.5 mm onwards, an improvement in the fire-resistant properties is observed. Unlike fabrics coated only with PU, the addition of wool powder allows the fabrics to resist the flame at 5 and 10 s. Water and air permeability properties of the coated fabrics were also evaluated and show interesting and complementary results. Integration of wool powder as a flame retardant is a promising approach to develop fire-resistant fabrics that can lead to wide applications in fire protection and safety. [ABSTRACT FROM AUTHOR]

Sediment is the ultimate sink of environmental pollutants. A total of 128 surface sediment samples were collected from 8 rivers and 3 reservoirs in Maoming City, Guangdong Province. This study assessed the content and distribution of brominated flame retardants in sediments. The acute toxicity effects of tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDs) in sediments were evaluated using Caenorhabditis elegans as model organisms. The concentration of TBBPA in sediments ranged from not detected (ND) to 12.59 µg/kg and was mainly distributed in the central area, which was affected by the emission of TBBPA from residential and factory. The concentration of HBCDs ranged from ND to 6.31 µg/kg, and the diastereoisomer distribution was consistent, showing a trend close to the South China Sea. The composition pattern of HBCDs in the surface sediments from rivers were 41.73%–62.33%, 7.89%–25.54%, and 18.76%–40.65% for α-, β-, and γ-HBCD, respectively, and in the sediments from reservoirs were 26.15%–45.52%, 7.44%–19.23%, and 47.04%–61.89% for α-, β-, and γ-HBCD, respectively. When the sum of concentrations of TBBPA and HBCD in sediments were above high levels, reactive oxygen species in nematodes significantly increased, resulting in an oxidative stress response. Intestinal permeability was also enhanced, causing intestinal damage. In addition, in terms of this study, TBBPA had a greater impact on biotoxicity compared to HBCDs, and more attention should be paid to the toxic effects of the river ecosystem organisms in Maoming City, Guangdong Province. This study can complement the pollution database in the study area and provide basic data for pollution control. [Display omitted] [ABSTRACT FROM AUTHOR]

Lignin is classified as the second most abundantly available biopolymer after cellulose and as a main aromatic resource material. Lignin structure differs based on sources of origin and species of biomass with around 15–40% of lignin content based on dry weight. It is extracted from various types of lignocellulosic biomass through different pulping extraction methods. After extraction, lignin can be further functionalized through different chemical reactions to meet the requirements and specifications before being used in end products. Therefore, in this review paper, the details on extraction and the type of lignin, as well as chemical functionalization, are discussed. The chemical functionalization can be used to modify the lignin such through phenolic depolymerization or by other aromatic compounds, creating novel chemical active sites to impact a reactivity of lignin and through functionalization of hydroxyl functional group for enhancing its reactivity. Furthermore, the recent sustainable application of lignin was discussed in different fields such as nanocomposite, flame retardant, antioxidant, cosmetic, natural binder and emulsifier. This review hence provides a summary of the current stateoftheart in lignin technology and future outlook of potential application areas. [ABSTRACT FROM AUTHOR]

To address the increasing demand for sustainable biomaterials because of the excessive usage of fossil fuel and growing concerns with the environment, a novel biodegradable and environmentally friendly rigid polyurethane foam (RPUF) has been synthesized. These foams are derived from chemically modified soybean oil-based polyol (SBO-polyol) obtained through the formation of oxirane followed by the opening of the oxirane reaction. Polyurethane foam is generally used in construction, furniture, and automobile industries but is highly flammable and releases toxic fumes in combustion. In this study, an efficient synergistic effect of non-halogen flame-retardant (FR) melamine salt, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA) was synthesized from 2-carboxyethyl(phenyl)phosphinic acid (CEPP) and melamine (MA). Fourier transform infrared (FT-IR) spectroscopy characterized the chemical structure of CMA. Three different FRs, MA, melamine cyanurate (MC), and CMA were separately introduced in increasing quantities for the foam preparation to suppress the flame during combustion. The influence of these FRs on the thermal properties, flame retardancy, morphology, physical, and mechanical properties of the prepared RPUFs was studied through closed cell content, apparent density, compression test, horizontal burning test, thermogravimetric analysis (TGA), and gel permeation chromatography (GPC), scanning electron microscopy (SEM). The addition of 28.56 wt% of MA (MA-15), MC (MC-15), and CMA (CMA-15) presented a burning time of 10.1 s with weight loss of 5.34% and 28.4 s with 13.02% and 15.25 s with 8%, respectively. The findings demonstrated that all three FRs gave RPUF good FR properties. [ABSTRACT FROM AUTHOR]

This paper presents the design of 1x4 array microstrip antenna utilizing modified backline feeding technique at 5.8 GHz frequency band. The antenna, designed on flame retardant (FR-4) substrate with a dielectric constant of 4.4, aims to achieve reduced harmonics and mutual coupling between closely spaced antenna elements. The primary scope of the paper is investigating the performance of a single band microstrip antenna employing the proposed modified backline feeding method. Moreover, developed design came out with the result and critical analysis by various parameters such as, gain, return loss, voltage standing wave ratio (VSWR), and directivity. Therefore, the proposed design of microstrip antenna with backward linefeed (BLF) demonstrates a directivity of 10.29 dBi, return loss of -21.947 dB, and VSWR of 1.173; are significant improvement compared to recent literature shown in this paper. The adoption of proposed back line feeding technique (BLF) represents a promising alternative for addressing poor wireless connectivity issues in terms of antenna design, gain, and direction within microstrip technology. [ABSTRACT FROM AUTHOR]

Antenna is a backbone of communication system, and with the advent of technology, numerous innovations have been made to advance antenna development. An antenna, functioning as a smart device, transmits and receives signals while also working as a transducer. Wireless communication requires a useful device for transmitting and receiving electromagnetic waves. Wireless fidelity (Wi-Fi) is a specific type of wireless communication technology used to transmit data over the internet network. The bandwidth and signal coverage of Wi-Fi have significant limitations. Therefore, an antenna is crucial for improving signal reception to address this issue. This article presents the designing and developing of a cost-effective circularly polarized (CP) 2x2 multiple input multiple output (MIMO) antenna customized for Wi-Fi applications. The application of a notched circular patch antenna serves to achieve circular polarization. The radius of the circular patch is 0.26 X, and the proposed MIMO antenna effectively showcases CP, characterized by an axial ratio (AR) of 1 dB at 5 GHz and an impressive bandwidth spanning 0.2 GHz (4.9-5.1 GHz). Additionally, the antenna is designed to achieve a high-isolation 2x2 MIMO setup, ensuring antenna isolation surpassing 20 dB. By utilizing the flame retardant (FR4) substrate, presented MIMO antenna strikes a balance between cost-effectiveness and operational efficiency for its intended application, and directional radiation patterns are well-aligned within the desired frequency range. [ABSTRACT FROM AUTHOR]

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Trains play an important role in the sustainable mobility of the future. The changes in the market are reflected in the number of newly approved series by the German Federal Railway Authority (EBA); 226 new designs and redesigns of train cars were approved for use on German rails in 2019. Phenol-formaldehyde resins are used extensively specifically for railcar interiors. However, phenol-formaldehyde resins release carcinogenic vapors during and even after production if not completely sealed. As a result, European production standards and requirements have been increased, making the material less economical and increasingly difficult to enter the market. Further bans aimed at lower formaldehyde release limits are currently being considered by the European Union's Committee for Risk Assessment (RAC) and Committee for Socioeconomic Analysis (SEAC). In order to develop and design alternative materials, it is important to meet the requirements for stiffness, light weight, insulation and sustainability simultaneously. This research aim is therefore to develop a new class of material for interior components with improved stiffness, lower weight, lower CO2 footprint and no health hazards. The approach is to develop advanced composite sandwich panels that retain the ability to be molded into complex structures for interior applications. This is done through a thermoplastic honeycomb core structure that is manufactured directly from sheet material and fiber reinforced organo-sheets as the outer layers. The base matrix for all layers is kept uniform for better recyclability and consists of polycarbonate (PC) with sufficient flame retardant properties to provide an environmentally friendly alternative to existing phenolic resin and aramid epoxy honeycomb solutions while still complying with the security norms. [ABSTRACT FROM AUTHOR]

The flame resistance characteristics of corrugated flame-retardant system for hydrogen/methane explosion were researched by visualization experiment. The influence laws of structure parameter and hydrogen doping ratio on the explosion resistance parameters were summarized. Result indicates that the flame could be effectively quenched and there was a clear correspondence between flame propagation and explosion parameters at the front and rear ends. Flame propagation at the front-end could be greatly affected by flame-retardant system, thereby affecting its propagation velocity inside the narrow channel. As the flame resistance failed, the flame at the rear-end would appear an obvious acceleration. As the porosity and hydrogen ratio increased, the failure probability continued to increase. An increase in flame-retardant element thickness was conducive to flame resistance success. Above factors could affect the flame resistance effect by influencing the intensities of flame and pressure wave entering front-end of flame-retardant system, as well as the degree of weakening inside the narrow channel. • Flame resistance characteristic of corrugated flame-retardant system was researched. • Pressure change, flame temperature and its propagation characteristic were obtained. • Influence law and mechanism of working condition on flame resistance were analyzed. • Correlation between flame resistance process and explosion parameters was explored. • Effective suggestion for practical application and protection methods were proposed. [ABSTRACT FROM AUTHOR]

Polymerization of benzoxazine at low temperatures is important because the high‐temperature polymerization restricts its utilization in a wide range of applications, though the polybenzoxazines possess excellent properties. The effect of nitro functionality and various substituents on the thermal curing of benzoxazine and the flame‐retardant behavior are mainly focused in this study. In the present work, 2,2′‐methylenebis(4‐nitrophenol) (NBP) was synthesized from 4‐nitrophenol and is used for the synthesis of benzoxazine derivatives with five structurally different aromatic amines. As the synthesized benzoxazine contains nitro‐groups in the phenolic part and various substituted functional groups in different positions of the amine part, the curing temperatures significantly varied among each other. The effect of different substituents on the thermal ring‐opening polymerization (ROP) of benzoxazine was studied with exotherms of the DSC thermogram. The 4‐fluoroaniline and 2‐aminobenzotrifluoride‐based benzoxazines show the highest and lowest curing temperatures of 272 and 189 °C, respectively, which is based on their substituents and their position that can act as an internal catalyst. The resulting polybenzoxazines possess higher char yield (49% ≤ 63%) and higher values of LOI (37 ≤ 43) including excellent flame retardant (UL94‐V0) behaviors suggesting that the polybenzoxazine can be used as coatings for high‐performance industrial applications. [ABSTRACT FROM AUTHOR]

Optimizing composite materials is crucial for engineering advancements because it allows for the creation of materials tailored to specific functional requirements, thereby enhancing efficiency, safety, and sustainability. This study examines both the combined and individual effects of long flax fiber (LFF) bundles, short basalt fibers (BF), and rice husk powder (RHP) on the properties of polypropylene (PP) hybrid composites. LFF primarily provides mechanical strength, BF enhances mechanical, thermal, and flame‐retardant properties by filling gaps, and RHP reinforces and improves the overall composite. Contrary to previous studies that relied on random combinations, this research employs a systematic Box–Behnken design (BBD) for three variables: LFF plies, BF, and RHP by weight percentage. This approach facilitated the development of a new second‐order regression equation via response surface methodology (RSM), clarifying the contribution of each component, with R2 values exceeding 0.85, indicating high predictability. Optimization, conducted using a non‐dominated sorting genetic algorithm (NSGA‐II), demonstrated that the optimal composites significantly outperformed the non‐optimized ones in mechanical strength, thermal stability, and flame retardancy. Compared to the average values before optimization, improvements post‐optimization included increases of 49.86% in tensile strength (TS), 38.82% in TS modulus, 73.93% in char yield (YC), and 29.81% in peak heat release rate (pHRR). Specifically, the fire performance index improved by 237.5% and the fire growth index by 101.33%, compared to pure PP, highlighting significant advancements in fire safety. This study shows that mathematical equations can predict composite properties, helping to select balanced compositions without sacrificing flammability. Highlights: Multi‐filler approach technique used for manufacturing of PP composites.LFF, BF & RHP optimize mechanics & flammability.Box–Behnken design predicts optimal composition for superior properties.NSGA‐II optimization improves tensile, thermal & flame retardant properties. [ABSTRACT FROM AUTHOR]

This study endeavors to enhance the safety of lithium‐ion batteries (LIBs) by synthesizing a polyamide acid (PAA)/Al2O3 composite spinning solution using 4,4′‐diaminodiphenyl ether (ODA) and pyromellitic anhydride (PMDA) as monomers, and nano‐Al2O3 as a thermal conductivity filler. Subsequently, the PAA/Al2O3 fiber membrane is fabricated via electrostatic spinning, followed by gradient heating imidization to produce a polyimide (PI)/Al2O3 composite membrane. This membrane is then dipped into a boron nitride (BM) slurry to ultimately yield an organic–inorganic PI/Al2O3/BM composite separator with superior flame‐retardant and thermal conductivity properties. The thermal stability, flame retardancy, electrolyte wettability, mechanical integrity, and cycle rate performance of the composite membranes are rigorously evaluated. The results demonstrate that the PI/5% Al2O3/BM composite membrane exhibits the most favorable overall performance, with no shrinkage observed at 200°C and no significant changes after sustained ignition for 10 s. The incorporation of the thermal conductivity Al2O3 filler significantly enhances the heat transfer properties of the composite separator. The room temperature ionic conductivity reaches 2.786 mS cm−1 after electrolyte absorption, and the initial discharge capacity of the assembled battery is 156.28 mAhg−1. Following 100 charge/discharge cycles at 0.2C, the capacity retention rate is 97.7%, and at a discharge rate of 5C, the capacity retention rate is 74.9%. [ABSTRACT FROM AUTHOR]

Replacing antimony trioxide (Sb2O3) with an environmentally friendly alternative is of great scientific and commercial value for studying the flame retardant properties of flexible PVC (fPVC) films in automotive interior materials. This study develops flame retardant fPVC films with reduced Sb2O3 content by introducing stannic oxide (SnO2) and zinc borate (ZB). The results indicate that the fPVC film with ZB partially replacing Sb2O3 exhibits superior flame retardancy and smoke suppression compared to the product containing SnO2. The peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of 2ZB/2Sb2O3 fPVC film are reduced by 32.1%, 27.5%, and 22.1%, respectively, compared to that of 4Sb2O3 contained fPVC film. The increase in flame retardancy is attributed to the presence of ZB, which compensates for the deficiency of char formation ability of Sb2O3 in the condensed phase. The PHRR and THR of 2SnO2/2Sb2O3 fPVC film decrease by 27% and 12.5%, respectively, compared to that of 4Sb2O3 fPVC film, while the TSR increases by 16.5%. This study develops a straightforward approach to creating a flame retardant fPVC film that is suitable for the latest industrial application in automotive interior materials. [ABSTRACT FROM AUTHOR]

The development of green and efficient bio‐based flame retardants is very important for the development of flame‐retardant cellulosic paper. In this study, a novel type of starch‐based synergistic flame retardant (SAPU) was prepared using corn starch as carbon sources, amino trimethylphosphonic acid, and urea as phosphorus and nitrogen sources through the one‐pot method. Subsequently, the flame‐retardant cellulosic paper was prepared by impregnation, and the flame retardancy of the cellulosic paper was evaluated by vertical combustion, limiting oxygen index (LOI), and thermogravimetric analysis. The results demonstrated that the SAPU exhibited a favorable flame‐retardant effect on cellulosic paper. At a concentration of 25.0%, the vertical burning residue of flame‐retardant paper accounted for 49.16% of the total length of the paper sample, while the LOI was 39.4%. The tensile strength and burst index of cellulosic paper were found to be decreased by 6.36% and 19.1%, respectively, in comparison to the base paper. Conversely, the ring crush strength was observed to be increased by 156.2%. The carbon residue rate at 700°C under a nitrogen atmosphere rose from 11.56% of the base paper to 28.77% of the flame‐retardant paper. The flame‐retardant SAPU effectively improved the thermal stability of cellulosic paper. [ABSTRACT FROM AUTHOR]

Highlights: NaTFSI/SUL:OTE:FEC facilitates the formation of S, N-rich, dense and robust cathode–electrolyte interphase on NaNMF cathode, which improves the cycling stability under high voltage. By utilizing NaTFSI/SUL:OTE:FEC, the Na||NaNMF batteries achieved an impressive retention of 81.15% after 400 cycles at 2 C with the cutoff voltage of 4.2 V. The study offers a reference for the utilization of sulfolane-based electrolytes in sodium-ion batteries (SIBs), while the nonflammability of the NaTFSI/SUL:OTE:FEC enhances the safety of SIBs. Sodium-ion batteries hold great promise as next-generation energy storage systems. However, the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs. In particular, an unstable cathode–electrolyte interphase (CEI) leads to successive electrolyte side reactions, transition metal leaching and rapid capacity decay, which tends to be exacerbated under high-voltage conditions. Therefore, constructing dense and stable CEIs are crucial for high-performance SIBs. This work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H, 1H, 5H-octafluoropentyl-1, 1, 2, 2-tetrafluoroethyl ether, which exhibited excellent oxidative stability and was able to form thin, dense and homogeneous CEI. The excellent CEI enabled the O3-type layered oxide cathode NaNi1/3Mn1/3Fe1/3O2 (NaNMF) to achieve stable cycling, with a capacity retention of 79.48% after 300 cycles at 1 C and 81.15% after 400 cycles at 2 C with a high charging voltage of 4.2 V. In addition, its nonflammable nature enhances the safety of SIBs. This work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes. [ABSTRACT FROM AUTHOR]