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The practical application of lithium metal batteries (LMBs) is hindered by the issues of flammable electrolytes, lithium dendrites and the resulting thermal runaway. Designing flame‐retardant electrolytes with high performance is a valid strategy to break the current dilemma. In this work, the flame retardant of triphenyl phosphate (TPP) is elaborately encapsulated into the polymer shell of polyacrylonitrile (PAN) and polyvinylidene fluoride‐hexafluoropropylene (PVDF‐HFP) to realize the controllable release of TPP during the soaking process. The resulting TPP@PAN/PVDF‐HFP fiber membrane holds high thermal stability, high mechanical strength, and low swelling rate, which is essential for the preparation of flame‐retardant gel polymer electrolyte (GPE). As demonstrated, the TPP@PAN/PVDF‐HFP GPE can deliver high Li+ transference number of 0.877, low interfacial activation energy barrier of 26.6 kJ mol−1 and heterogeneous SEI composition of Li3PO4/Li2CO3/LiF. The corresponding Li||Li cells achieve stable voltage polarization over 1000 h, and the Li||Cu cells display high plating/stripping CE of 99.1%. Meanwhile, the optimized Li||LiFePO4 batteries exhibit high reversible capacity of 158 mAh g−1 after 200 cycles at 0.5 C, and present outstanding fire resistance through the thermal runaway and puncture test. This study will open window for the design of high‐safety electrolytes to promote the practical application of LMBs. [ABSTRACT FROM AUTHOR]

Inspired by the significant catalytic charring effect of metal–organic frameworks (MOFs), Cu‐MOF decorated ammonium polyphosphate (APP@Cu‐MOF) was prepared by coupling agents to improve the fire safety of epoxy resin (EP). After adding 9 wt% APP@Cu‐MOF, the fire performance of EP is significantly improved with limiting oxide index (LOI) value of 29.4 and UL‐94 V‐0 rating. The peak heat release rate (PHRR), total smoke production (TSP), CO production, and CO2 production of EP composite samples decreased by 34.6%, 54.7%, 24.6% and 30.0%, respectively. It is proposed that the synergistic effect among Cu‐MOF and APP promoted the char formation of EP. The dense carbon layers formed a barrier that prevented the transfer of heat and inhibited the release of toxic gases, thus acting as a flame retardant. This work provides a new strategy to develop a high‐efficient MOF‐decorated flame retardant with smoke inhibition, toxicity reduction, and catalytic carbonization effect. [ABSTRACT FROM AUTHOR]

The ultraviolet/flame retardant protection cotton fabric is successfully prepared using a spray baking process with tannic acid (TA) and phytic acid (PA) as key ingredients to address the issues of cotton fabric such as high flammability and lack of ultraviolet (UV) resistance. With respect to the treated fabric by 4 wt% PA solution and 3 wt% TA solution, it presented 29.5% limited oxygen index (LOI) value, 8.0 cm damaged length and 26.4 ultraviolet protection factor (UPF), while they were 28.3%, 7.5 cm and 30.6 for treated fabric by 3 wt% PA solution and 4 wt% TA solution, which indicated that in the mixed system, although TA primarily acted as an anti‐UV agent, it also exhibited flame retardant properties, and PA primarily functioned as a flame retardant and could provide a certain degree of UV protection. The prepared cotton fabric through this facile method presented excellent UV/flame retardant protection capabilities, and improved the functional efficiency of TA and PA materials. Moreover, as‐prepared fabric showed great application potential, especially in outdoor‐applied fields such as sportswear, sunshade tents, sunshade hats, and so on. [ABSTRACT FROM AUTHOR]

The rising awareness of fire safety among consumers has driven the demand for fire retardants (FRs) that are both cost‐effective and efficient across various industries, particularly in textiles. Traditional FRs often compromise fabric softness, resulting in undesirable tactile texture and stiffness changes. While the external addition of softeners can mitigate the stiffness, it may introduce issues such as a greasy texture and increased flammability. This study introduces ethanolamine polyphosphate (EAPP), an innovative organic polyphosphate, as an effective fire retardant that preserves the softness of textiles. Comprehensive evaluations are conducted on EAPP‐treated textiles, revealing significant improvements in fire retardancy without compromising fabric quality. EAPP treatment (15 wt.% aqueous solutions) increases the limiting oxygen index (LOI) of pure cotton textiles from 17% to 36% and significantly reduces the peak heat release rate (pHRR) and total smoke rate (TSR) as measured by cone calorimetry. Unlike conventional FR products that form FR‐salt crystal particles on the fabric surface after drying, EAPP forms a smooth FR protective layer on the fabric, enhancing mechanical fastness and maintaining tactile qualities. These findings highlight EAPP's potential as a non‐washing durable, spray‐on fire retardant solution for textiles, combining safety with user comfort. [ABSTRACT FROM AUTHOR]

In this study, the challenges of brittleness and flammability in Polyamide 6/glass fiber (PA6/GF) composites, which are crucial for heat‐resistant and stress‐bearing structural parts, are addressed. Polyphosphazene (PZ) elastomers, known for their exceptional flame‐retardant properties, are introduced to enhance the robustness and safety of these composites. Specifically, poly(diaryloxy)phosphazene (PDAP) and poly(difluoroalkoxy)phosphazene (PDFP) are utilized, both contributing to the improved toughness and flame resistance of the PA6/GF composites. Experimental results show that PDAP mainly played the role of solid‐phase flame retardant, while PDFP mainly acted the role of gas‐phase flame retardant. For PA/PZs composites without adding GF, PDFP plays a more efficient flame retardant effect than PDAP. By introducing 15 Vol% of PDFP, the limiting oxygen index (LOI) of the composite reached 26.1%, while the notched impact strength increased by 297%. For PA/PZs/GF composites, PDAP plays a better flame retardant role than PDFP. Under the action of 30 vol% GF and 15 vol% PDAP, the LOI of PA6/PDAP/GF composite reached 26.8%, and the notch impact strength improved to 18.7 kJ/m2, which is 165% higher than that of PA6/GF, and the UL‐94 test reaches V‐0 level. The findings of the study highlight the potential of PDAP and PDFP to act as dual‐function modifiers. These modifiers can considerably ameliorate both the impact resistance and flame retardancy of PA6 and PA6/GF composites. Such dual enhancement surpasses the typical trade‐offs seen in conventional composites, indicating a constructive direction for future material innovation. Highlights: Polyphosphazenes simultaneously enhance PA6's toughness & flame resistance.Distinct flame retardant mechanisms found in PDAP and PDFP.GF presence alters PDAP and PDFP's flame retardant efficacy.PDAP shows superior flame resistance in GF‐reinforced PA6 composites.Without GF, PDFP outperforms PDAP in enhancing flame retardancy. [ABSTRACT FROM AUTHOR]

The enhancement of flame resistance and mechanical strength is critical for the utilization of rigid polyurethane foam (RPUF) composites. In this study, the efficient synergistic flame‐retardant system, incorporating dimethyl methylphosphonate (DMMP) and expandable graphite (EG), with the addition of refined alkali lignin (A‐lignin) were aimed to superior fire resistance and mechanical integrity for RPUF. Furthermore, the flame retardancy and charring ability of obtained RPUF were obviously enhanced. Notably, an RPUF mixture containing A‐lignin, DMMP, and EG demonstrated substantial charring at elevated temperatures, improved limiting oxygen index, and met the UL‐94 V‐0 rating. Cone calorimeter test indicated that this formulation produces less heat and smoke than pure RPUF. The flame‐retardant efficacy of obtained RPUF was attributed to the formation of a protective char layer coupled with the free radical neutralization properties of DMMP, collectively enhancing the flame retardancy obtained RPUF. Additionally, this RPUF variant showed significant advancements in both mechanical and thermal performance. This study outlines a successful strategy for developing RPUF composites endowed with enhanced flame retardancy and mechanical strengths. [ABSTRACT FROM AUTHOR]

Steel slag (SS) as solid waste, has low resource utilization efficiency and seriously endangers environmental safety and human health. To explore the potential utilization value of SS and address the flammability challenge of rigid polyurethane foam (RPUF), with a novel flame‐retardant system composed by SS and dimethyl methyl phosphonate (DMMP) was explored. The DMMP/SS system effectively improved the high temperature stability of the RPUF composites. When the mass ratio of SS and DMMP was 1:1, the limiting oxygen index of RPUF/DMMP/SS reached 23.1 vol% and UL‐94 vertical combustion tests passed V‐2 level. Upon incorporation of 15 wt% DMMP, the initial decomposition temperature (T−5 wt%) reduced to 165.3°C, a decrease of 32.2%, while the Tmax2 and residue yield at 700°C exhibited negligible alteration. The peak heat release rate of RPUF/DMMP/SS composite (118.20 W g−1) was 11.02% lower than that of pure RPUF, indicating the significant enhancement of fire safety of the composites. Results confirmed that a synergistic flame‐retardant mechanism was existed between DMMP and SS in enhancing the fire safety of RPUF composite. Introducing a 20 wt% SS content reduces the ID/IG ratio to 1.85, thereby markedly enhancing its heat resistance. This work provides a new application field of SS and paves a novel approach to enhance fire safety of polymers. [ABSTRACT FROM AUTHOR]

Cyclotriphosphazene (CP) is a cyclic inorganic compound with the chemical formula N3P3. This unique molecule consists of a six‐membered ring composed of alternating nitrogen and phosphorus atoms, each bonded to two chlorine atoms. CP exhibits remarkable versatility and significance in the realm of materials chemistry due to its easy functionalization via facile nucleophilic substitution reactions in mild conditions as well as intriguing properties of resultant final CP‐based molecules or polymers. CP has been served as an important building block for numerous functional materials. This review provides a general and broad overview of the synthesis of CP‐based small molecules through nucleophilic substitution of hexachlorocyclotriphosphazene (HCCP), and their applications, including flame retardants, liquid crystals (LC), chemosensors, electronics, biomedical materials, and lubricants, have been summarized and discussed. It would be expected that this review would offer a timely summary of various CP‐based materials and hence give an insight into further exploration of CP‐based molecules in the future. [ABSTRACT FROM AUTHOR]

Highlights To enhance the flame retardant property of fiber‐reinforced polymer composites without adding more flame retardants, we prepared film stacking composites by maintaining a total flame retardant content of 20% and applying a gradient flame retardant strategy. The gradient composites have been designated as 3113FRPLA/F and 1331FRPLA/F, respectively. 3113FRPLA/F is characterized by an augmented concentration of fire‐resistant additives in the surface layer, while 1331FRPLA/F features a reduced content. 20%FRPLA/F is prepared with a homogeneously distributed flame retardant composition. Results derived from LOI test and cone calorimeter test unequivocally demonstrate that 3113FRPLA/F outperforms both 1331FRPLA/F and 20%FRPLA/F in improving flame retardancy. The LOI value of 3113FRPLA/F is 36.1%, exceeding that of 20%FRPLA/F and there is also a reduction in the pk‐HRR compared with 20%FRPLA/F. It is of interest to note that 3113FRPLA/F exhibits the most effective heat insulation properties while 20%FRPLA/F has the worst, which is reflected by the infrared thermal imaging results. It bears mention that the impact strength and tensile strength of 3113FRPLA/F surpasses that of 20%FRPLA/F. In summary, 3113FRPLA/F, characterized by its increased surface concentration of flame retardants, demonstrates the most superior overall performance. The characteristics of PLA/fiber composites using a gradient strategy were compared. The LOI value of 3113FRPLA/F is 36.1%, exceeding that of 20%FRPLA/F. 3113FRPLA/F has the best heat insulation effect while 20%FRPLA/F has the worst. The impact strength and tensile strength of 3113FRPLA/F surpasses 20%FRPLA/F. Improving the surface flame retardant concentration increases the overall property. [ABSTRACT FROM AUTHOR]

Modern society relies heavily on producing commercial and industrial plastics to improve the quality and quantity of our lives. However, increased fire risks threaten commercial operations and the potential impact of high‐performance electronic and transportation technologies that utilize polymeric materials. Despite significant monitoring and reduction of commonly used halogenated flame retardants, their worldwide usage still poses environmental hazards. Many non‐halogenated flame‐retardant compounds are viable additives for synthetic polymers; however, their incorporation often results in reduced composite homogeneity and mechanical strength. This review focuses on reactive flame retardants and the effect of polymer structure on inherent flame retardance in recent studies. The synthesis and characterization of polymeric systems (e.g. polyurethanes, polyamides, polyimides, polyesters and epoxy resins) are discussed in terms of structure–flame‐retardant performance using a complement of analytical tools, including thermogravimetric analysis, cone calorimetry, limiting oxygen index and UL 94 testing. These commercially important polymeric systems represent a broad compositional space for future adaptation and the discovery of increasingly modular polymeric materials with, while also contributing to the fundamental understanding of unique combinations of gas‐ and condensed‐phase mechanisms of flame retardance. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Although epoxy resin (EP) has been widely used in many fields, it is still urgent to effectively improve its flame retardancy by halogen‐free strategies. Herein, a silicon‐containing cyclotriphosphazene derivative (HEP‐Si) was synthesized by nucleophilic substitution and silicon–hydrogen addition reaction using eugenol, hexachlorophosphazene and triethylsilane as raw materials. Then it served as a halogen‐free flame retardant for an EP/4,4′‐diaminodiphenylmethane system, and its performance was compared with that of commercial flame retardant hexaphenoxycyclotriphosphazene (HPP). The results showed that although the initial thermal decomposition temperature (T5%) of the cured products of EP/HEP‐Si was slightly lower than that of pure EP, T5% did not decrease further as the amount of HEP‐Si increased, indicating that good thermal stability was maintained. In addition, the char yield of the cured products of EP/HEP‐Si was significantly increased (more than 20 wt%) compared to that of pure EP. The cured EP with the addition of HPP and HEP‐Si both achieved a V‐0 rating in UL‐94 vertical burning test at 0.5 wt% phosphorus content, while the limiting oxygen index of the EP/HEP‐Si system was higher, reaching 33.2%. From cone calorimetric test results, the peak heat release rate, total heat release and total smoke production of the cured products of EP/HEP‐Si decreased by 61.5%, 37.1% and 26.2%, respectively, compared with that of pure EP. The cured EP/HEP‐Si materials also exhibited good thermomechanical and mechanical properties. Therefore, HEP‐Si is suggested to be a promising P/N/Si‐containing halogen‐free flame retardant for EP. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

It is difficult to effectively manage the emission of harmful smoke from flame‐retardant modified epoxy resins (EP). In order to solve this difficulty, a highly efficient flame‐resistant PAD containing phosphorus, nitrogen, and sulfur was synthesized using a simply one‐pot method employing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole (AMT), and terephthalaldehyde for not only enhancing its flame retardant properties but also effectively suppressing the emission of fumes. Results have confirmed that the incorporation of 5 wt% flame retardant into the EP successfully passed the UL‐94 V‐0 rating, besides 24.2% reduction in the peak of smoke produce rate (PSPR), with outstanding fire‐resistant properties and effectively reduce smoke emissions. In addition, incorporating 7.5% of PAD into EP increased its flexural strength and modulus, from 78.4 and 2917.5 to 86.6 and 3162.9 MPa, respectively. Due to the abundance of reactive groups including sulfhydryl and secondary amine in PAD, as well as the nitrogen atoms presented in the thiadiazole and benzene rings of the phosphaphenanthrene structure, which could create hydrogen bonds with the matrix and participated in π‐π interactions, therefore, the mechanical properties of flame retardant epoxy resin (FREP) were greatly enhanced. [ABSTRACT FROM AUTHOR]

This study presents a novel approach to fabricate 3D‐printed phosphorous‐based acrylate monomers using stereolithographic 3D printing technology, aiming to create demonstrators with exceptional shape‐memory characteristics and robust flame retardant properties. The synthesized materials combine the advantages of 3D printing precision with the intrinsic flame retardancy of phosphorous‐based monomers, offering a versatile solution for applications requiring both shape memory functionality and fire resistance. The limiting oxygen index (LOI) value of the intrinsically flame‐retardant shape‐memory polymer (IFR‐SMP) can reach 34%, and the vertical combustion rating after UL 94 can obtain V‐0. The mechanism of the IFR‐SMP flame retardant mainly includes terminating a free‐radical chain reaction and gas phase dilution, which indicates that the gas‐phase mechanism plays an important role in the flame retardancy. This work advances the frontiers of 3D printing technology by demonstrating the synergistic potential of shape memory and flame retardancy within a single material system, providing a pathway toward the development of innovative and resilient materials for the future. [ABSTRACT FROM AUTHOR]

Background: Organophosphate flame retardants (OPFRs) are extensively distributed in our environment, prompting concerns about potential health hazards, including lung injuries resulting from OPFR exposure. Methods: The present study recruited 125 lung cancer patients, assessing their exposure to 10 OPFR compounds through urine samples. The final analysis comprised 108 participants after excluding those lacking epidermal growth factor receptor (EGFR) status and those with chronic kidney disease. Demographic and clinical characteristics, as well as urinary OPFR concentrations, were compared based on OPFR detection. Spearman correlation was conducted to explore the relationship between OPFR compounds, while logistic regression was used to identify OPFR compounds associated with EGFR mutation. Results: The study revealed widespread OPFR exposure among lung cancer patients, with an overall detection frequency of 99.07%. Tris(2‐butoxyethyl) phosphate (TBEP) exhibited a strong correlation to its metabolite bis(2‐butoxyethyl) phosphate (r = 0.88, p < 0.01). Patients with TBEP in their urine had higher percentage of wild‐type EGFR and the detection of TBEP was associated with a reduced likelihood of mutant EGFR expression. Conclusions: OPFR exposure was prevalent in lung cancer patients, with TBEP detection identified as a factor with lower EGFR mutation expression. This study contributes to the understanding of OPFR exposure in lung cancer patients and underscores the significance of TBEP in evaluating EGFR mutation in this population. [ABSTRACT FROM AUTHOR]

Aerogel fibers, known for their lightweight and exceptional thermal insulation properties, provide an ideal material solution for fabricating triboelectric nanogenerators (TENGs) for self‐powered wearable electronics in extreme environments, such as firefighting gear. However, current aerogel fibers face limitations due to their poor mechanical properties and lack of performance stability under harsh conditions. Herein, a facile strategy for preparing silica/aramid nanofiber (ANF) composite aerogel fibers with interpenetrated dual networks and a silica‐dominant component (≈64 wt.%) is demonstrated; the unique structure and composition endow the composite aerogel fibers with high tensile strength (3.4 MPa), low thermal conductivity (0.033 W (m·K)−1), a large specific surface area (587 m2 g−1), and outstanding fire resistance at 95% porosity, combining the best properties of both ANF and silica aerogel. Moreover, the composite aerogel fibers exhibit excellent mechanical flexibility at extremely low temperatures (−196 °C) and maintain structural integrity even when exposed to flame for up to 5 min. Leveraging these exceptional properties, composite aerogel fiber‐based TENGs show high electrical output performance before and after combustion (>94% retention). The fabrication strategy offers promising opportunities for modulating the properties and functionalities of aerogel fibers on demand, holding great potential for future applications in wearable smart protective fabrics for extreme environments. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable solutions, this study investigates the potential of bio‐based polyamide 5.6 (PA56) as a promising alternative to petroleum‐derived polyamide 6.6 (PA66). Novel composites of PA56 and PA66 were prepared with the incorporation of glass fibers and flame retardant additives by twin screw extruder. Subsequently, these composites were subjected to comprehensive characterization to determine their performance. The physical, mechanical, rheological, thermal, and flammability properties of PA56 composites were investigated and compared with those of PA66 composites with the same formulations. This article aims to unveil the remarkable potential of bio‐based PA56 composites in industrial applications. The results showed that bio‐based PA56 exhibits comparable, and in some cases superior, performance to PA66 while offering the added advantage of environmental sustainability. The findings suggest that bio‐based polyamide 5.6 can serve as a sustainable alternative to petroleum‐derived polyamide 6.6, contributing to a greener future in industrial applications. Highlights: Bio‐based PA56 exhibits comparable properties to petroleum‐derived PA66.Incorporation of glass fibers and flame retardants enhances the properties of PA56.Findings propose PA56 as a sustainable alternative to PA66 in various applications. [ABSTRACT FROM AUTHOR]

Fire and mechanical performances of a bio‐based flax/furan resin composite are evaluated and, in order to assess their commercial potential, compared with those of conventional carbon/glass fiber‐reinforced composites. Fire retardant (FR) variants of flax/furan were obtained by adding FRs to the resin and using (i) flax or (ii) FR‐treated flax fabrics. With (i), the fire hazard of the composite could be reduced to minimum, without detrimental effect on the mechanical properties. However, use of FR‐flax fabric (ii) led to impairment of mechanical properties. This indicated that for optimized fire and mechanical properties, use of a FR in the resin matrix suffices; there is no advantage in using a FR‐treated flax fabric. Natural aging of the samples for 10 years followed by water aging indicated that water absorption in flax/furan composites was much higher than in comparable carbon/epoxy composites. While there was evidence of released acidic components such as acetic acid, oxalic acid, and so forth, in flax/furan composites, mainly from oxidative degradation of furan resin, there was no evidence of leaching of FR additives from the matrix. However, FR treatment of flax fabric affected the fiber–matrix interfacial adhesion, leading to considerable water absorption during aging and disintegration of the reinforcement. Highlights: Furan resins are naturally fire retardant, burn only under forced combustion.FR flax/furan composites obtained by adding FRs to the resin or the flax fabric.FR treatment of the flax impairs mechanical properties and water tolerance.FRs in the resin neither affect mechanical properties nor leach out in water. [ABSTRACT FROM AUTHOR]

In this study, a nanohybrid based on montmorillonite (oMMT2) was prepared through a two‐step method using Arquad MCB‐80 and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) as intercalation agents. The nanohybrid exhibited a basal spacing of 31.5 Å, which contained approximately 12.3% of Arquad MCB‐80 and 31.6% of DOPO. Various amount of oMMT2 nanohybrid was incorporated into a flame‐retardant polyethylene system containing aluminum trihydroxide and red phosphorus with a constant total additive content of 20 wt%. The dispersibility of oMMT2 in the composite matrix was evaluated by energy dispersive x‐ray mapping and x‐ray diffraction analyses. At a content of 3 wt% in the nanocomposite, oMMT2 showed a highly exfoliated state, while at a 5% content, a partially exfoliated and intercalated state was observed. A synergistic flame‐retardant effect between the nanohybrid and the mixture of aluminum trihydroxide and red phosphorus was found. The nanocomposite loading 3 wt% oMMT2 demonstrated the best flame retardancy, achieving a V‐0 rating of the vertical burning test with a limiting oxygen index of 27.6%. Moreover, the addition of the low oMMT2 contents (≤3 wt%) improved the mechanical properties of the flame‐retardant composite. [ABSTRACT FROM AUTHOR]

Sodium‐based rechargeable batteries are considered one of the strongest contenders for the next generation of power storage devices. Functional electrolytes with additives play a crucial role in influencing the electrochemical performance of sodium‐based batteries. The addition of small doses of additives can greatly enhance the electrolyte, improving energy density, cycling performance, and safety. This paper presents an overview of recent research focused on novel additives for sodium‐ion batteries (SIBs) and sodium‐metal batteries (SMBs). The additives are categorized based on their specific functions, including film‐forming, flame retardant, overcharge protection, high‐voltage, acid and water removal, inhibition of gas production, high and low temperature and protection of sodium metal anode. The working mechanisms for these additives are thoroughly explained. Finally, potential future research directions are proposed. [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]

In this work, FR‐PNX, an alkylphosphate oligomer was introduced into rigid polyurethane foam (RPUF) to fabricate FR‐PNX/RPUF composites. The flame retardancy, thermal stability, and combustion properties of composites were investigated by limiting oxygen index (LOI), thermogravimetric (TG), microcalorimetry (MCC), scanning electron microscopy (SEM), et al. The flame retardancy tests demonstrated that the incorporation of 50 phr of FR‐PNX yielded composites that the highest LOI of 23.6 vol% and achieved a V‐0 rating in the UL‐94 test. TG results indicated that FR‐PNX promoted the decomposition of FR‐RPUF in the process, but enhanced the high‐temperature stability of the composites. MCC analyses revealed that the addition of FR‐PNX suppressed the heat release during combustion, and FR‐PNX50/RPUF exhibited the lowest total heat release of 17.3 MJ/m2, a 35% reduction compared to the pure sample. Moreover, the peak heat release rate was decreased to 83.1 W/g, representing a 46.9% reduction compared to pure RPUF. SEM and Raman analyses of the char residue demonstrated that the incorporation of FR‐PNX facilitated the formation of a dense and continuous char layer in the FR‐RPUF, with increased graphitization degree of the char layer, thereby enhancing the composite's fire resistance through the development of a more stable fire barrier. [ABSTRACT FROM AUTHOR]

High‐efficient flame retardants (ZrP‐DDM) were synthesized successfully via ion‐exchange method, using diaminodiphenylmethane (DDM) modified layered zirconium phosphate (α‐ZrP). Trace addition of ZrP‐DDM in epoxy resins (EP) can enhance the flame‐retardant, smoke‐inhibition, mechanical, and thermal stability properties of EP composites. As shown in the results, ZrP‐DDM exhibits a better synergistic effect than α‐ZrP, and the EP composites containing 0.5 wt% ZrP‐DDM (EP/0.5ZrP‐DDM) show excellent flame‐retardant and smoke‐inhibition properties. Especially, EP/0.5ZrP‐DDM possesses a limiting oxygen index (LOI) of 33.7% with UL94 V‐1 rating, while the EP composites containing 0.5 wt% ZrP (EP/0.5ZrP) has a LOI of 30.1% and fails to achieve the UL94 rating. Furthermore, the peak heat release rate (PHRR), total heat release rate (THR), and smoke density rating of EP/0.5ZrP‐DDM decrease by 10.2%, 3.7%, and 8.2% compared with EP/0.5ZrP. Based on condensed‐phase product analysis, EP/ZrP‐DDM sample provides a gas source for intumescent char layer, and produces a stable phosphorus‐rich crosslinking structures during combustion, thus decreasing the fire hazard of the composite material. Meanwhile, the introduction of ZrP‐DDM has a less impact on tensile strength of EP composites compared with α‐ZrP, suggesting the addition of ZrP‐DDM effectively enhances the compatibility with the EP matrix, thereby maintaining excellent mechanical properties of the EP matrix. [ABSTRACT FROM AUTHOR]

Polylactic acid has good biodegradability and processability, but its flammability and serious droplet characteristics limit its development and application. Therefore, developing safer flame‐retardant PLA materials is crucial. This research develops a novel flame‐retardant polylactic acid (PLA) material blend, utilizing aluminum diethylphosphinate (AlPi), piperazine pyrophosphate (PAPP), and β‐cyclodextrin. Optimal synergy occurs at a 5:1 PAPP/β‐CD mass ratio with 4 wt.% AlPi. This combination significantly reduces the heat release peak from 294.89 to 144.21 kW·m−2 and generates non‐combustible residues. The sample forms a stable, uniform carbon layer during combustion due to hydrogen bond crosslinking and Lewis acid–base reactions. The activation energy (Eα) is raised from 264.99 to 281.08 kJ·mol−1 between 312 and 402°C. Thus, an AlPi‐PAPP‐β‐CD based P‐C‐N composite flame retardant is investigated, offering a promising research direction for developing fire‐safe polylactic acid materials. This research may yield valuable insights for diverse applications. [ABSTRACT FROM AUTHOR]

Nanocomposites containing impermeable two‐dimensional materials are of significant interest for protecting metals against corrosion. Incorporating 4‐aminobutyltriethoxysilane (ABES) functionalized tantalum nitride (TaN) into a coating matrix enhances the barrier effect due to TaN's notable chemical and thermal stability. When integrated with graphitic carbon nitride (GCN) in polyurethane (PU), functionalized TaN significantly improves corrosion resistance and fire‐retardant capabilities. Electrochemical evaluations of aluminum coated with varying amounts of functionalized TaN/GCN in PU demonstrated substantial enhancements in protective behavior in chloride environments. The PU nanocomposite exhibited superior flame retardancy, with significant reductions in peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) compared to pure PU. Flame retardancy tests demonstrated increased thermal stability, attributed to the synergistic effects between GCN and silanized TaN. Electrochemical impedance spectroscopy (EIS) measurements showed a high coating resistance of 8.89×1011 Ω cm2 for PU/functionalized TaN/GCN, even after 40 days of electrolyte exposure. Additionally, the PU/functionalized TaN/GCN coating demonstrated exceptional water repellency, indicated by a water contact angle (WCA) of 164°. Mechanical tests revealed that PU/functionalized TaN/GCN exhibited favorable adhesion strength and hardness, maintaining integrity even under prolonged immersion. These findings suggest that this nanocomposite is a promising coating component for aerospace applications. The integration of functionalized TaN/GCN within the PU matrix presents a novel approach to developing multifunctional coatings with enhanced performance across various metrics essential for aerospace materials. [ABSTRACT FROM AUTHOR]

Highlights Due to the exceptional flame retardancy, environmental protection, cost‐effectiveness, and ease of processing, halogen‐free flame‐retardant polyethylene (PE) composites are attracting wide attention. However, the addition of halogen‐free flame retardants usually leads to significantly decreased mechanical properties of PE composites, which greatly limits its application. Herein, we report a halogen‐free flame‐retardant PE/ethylene‐vinyl acetate copolymer composite (PE/EVA) with excellent flame retardancy and mechanical properties by combining compatibilizer, crosslinking agent, and carbon fiber. The presence of compatibilizer not only improves the compatibility of halogen‐free flame retardants and matrix, but also interacts with the crosslinking agent to form a cladding structure on the surface of carbon fiber. The enhanced interaction between carbon fiber surface and matrix then results in significantly enhanced flame retardancy and mechanical properties of the composite. Specifically, adding 4 phr compatibilizer, 0.5 phr crosslinking agent, and 10 phr carbon fiber will lead to the halogen‐free flame‐retardant PE/EVA composite with a UL‐94 V‐1 level, limiting oxygen index of 27.1, and an increased tensile strength by 84.02% reaching 19.12 MPa. Moreover, further carbon fiber surface modification can further enhance the flame retardancy of the composite probably due to a synergistic flame‐retardant effect caused by the surface modified nitrogen and silicon elements. As a result, the composite achieves UL‐94 V‐0 level and the limiting oxygen index of 27.7 with well‐retained high tensile strength of 15.19 MPa. This work provides a practical strategy for enhancing the flame retardancy and mechanical property of PE‐based composite simultaneously. Compatibilizer interacts with crosslinking agent to form a cladding structure on the surface of carbon fiber. Crosslinking agent promotes the formation of chemical bonds between modified carbon fiber, compatibilizer, and matrix. Carbon fiber surface modification can enhance the flame retardancy of the composite due to the synergistic flame‐retardant effect. [ABSTRACT FROM AUTHOR]

Integrating flame‐retardant additives into epoxy resins is an essential strategy for improving their fire resistance. However, introducing flame‐retardant groups often compromises the processability and mechanical integrity of such resins. In this research, we synthesized a novel, biobased flame retardant, referred to as DPN, using naringenin and chlorodiphenylphosphine as precursors via a straightforward single‐step process. The addition of DPN markedly decreased the viscosity of hydantoin epoxy resin, from 7468 to 1285 mPa s. Furthermore, when cured with 4,4‐diaminodiphenylmethane, the composite containing five equivalents of DPN (DPN‐5) exhibited a marked improvement in mechanical strength, reaching 190 MPa, significantly outperforming the pure thermoset (DPN‐0: 104 MPa), while preserving high transparency. Combustion tests further confirmed that DPN significantly boosts the flame resistance of the thermoset, with DPN‐5 achieving a limiting oxygen index of 37% and securing a UL‐94 V‐0 rating. Cone calorimetry analysis showed that DPN‐5 effectively reduced heat and smoke production during combustion, achieving a 13.4% reduction in peak heat release rate and a 28.2% decrease in total heat release compared to DPN‐0. This study underscores the potential of multifunctional biobased flame retardants derived from renewable resources in advancing the development of high‐performance materials. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

A new reactive flame‐retardant N′‐(1‐(4‐hydroxyphenyl)‐1‐(6‐oxido‐6H‐dibenzo[c,e][1,2]oxaphosphinin‐6‐yl)ethyl) benzohydrazide (DOPO‐BD) was synthesized via a two‐step reaction involving the Schiff base reaction between benzohydrazide and 4‐hydroxy acetophenone, followed by a reaction between the imine‐based condensation product and 9, 10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO). The chemical structure of DOPO‐BD was well characterized by Fourier transform infrared spectra (FTIR), 1H, 13C, 31P NMR, and high‐resolution mass spectrometry (HRMS). The DOPO‐BD was utilized as a reactive flame retardant and co‐hardener in DGEBA/DDS. The epoxy composites of varying phosphorus weight percentages were synthesized. UL‐94 and LOI tests were used to investigate the flammability of composites. The epoxy composites retained good transparency, which was measured by UV–vis spectroscopy. Thermogravimetric analysis (TGA) observed an increase in the thermal stability of epoxy composites in a higher temperature range with increased char yield. In the UL‐94 and LOI tests, EP/DOPO‐BD(1.5%P) sample gave a V‐0 rating and 30% LOI value. The cone calorimeter test indicated a decrease in total heat released (THR), peak of heat release rate (pHRR), and total smoke production (TSP) for EP/DOPO‐BD(1.5%P) in comparison with epoxy (EP). The mechanical properties and glass transition temperature (Tg) of the epoxy composites were determined by Dynamic mechanical analysis (DMA), which showed an increase in storage modulus and a decrease in Tg. [ABSTRACT FROM AUTHOR]

Wood presents excellent opportunities for sustainable urbanism as a renewable building material. Here, the chemical synthesis of a novel wood composites (3%PFeW) which owns flame‐retardance, water resistance, and degradability is investigated. The 3%PFeW is composed of porous wood framework impregnated with citric acid, 1,8‐octanediol, and the flame retardants (Fe3O4 and 2‐carboxyethyl phenyl hypophosphite (CEPPA)). The 3%PFeW's effective flame retardancy is realized by the introduction of Fe3O4 and CEPPA. Self‐extinguish phenomenon of 3%PFeW happens after being removed from flame. Moreover, 3%PFeW holds an LOI value of 27, reaching V0 flame retardant standard. The 3%PFeW exhibits exceptional water resistance, being proven by its water contact angle (100 °) as well as the low absorbed water content (only 6.5% after soaking 7 days). In addition, the wood composite shows degradable after immersion in NaOH for several days (71.37% degradation content after 7 days), which facilitates the recycling and reutilization of the wood framework after utilization. The modified wood with flame‐retardant, water resistant, and degradable capabilities shown here provides an appealing composite toward building area. [ABSTRACT FROM AUTHOR]

Climate change, shrinking resources, and rising raw material costs have pushed the industry to create more sustainable, and lightweight materials. Natural fiber composites are materials of interest for replacing conventional materials such as steel. Sunflower husks (SH), among many other natural fibers, are readily accessible as agricultural waste and have advantageous properties. In this study, sunflower husks were mixed with polypropylene (PP) matrix using a twin‐screw extruder, and then tests specimens for experimental characterizations were manufactured through injection molding. The tensile tests revealed that the inclusion of SH into PP decreased the load‐bearing capacity of the composites by around 20% and increased their impact resistance by over 200%, while reducing the ductility by about eight times. Moreover, magnesium hydroxide (Mg(OH)2) was incorporated into the composites as a flame retardant, and it has improved the stiffness and impact resistance of the composites. Besides, incorporation of SH and Mg(OH)2 elevated significantly the glass transition temperature of the composites. The use of Mg(OH)2 delayed 60% the flame retention of the composites observed from UL‐94 HB flammability testing. In summary, they could be suitable for components such as spare wheel wells, seat backs, trunk floor, the acoustic panel behind the door, and airbag housing. [ABSTRACT FROM AUTHOR]

Efforts to use transcriptomics for toxicity testing have classically relied on the assumption that chemicals consistently produce characteristic transcriptomic signatures that are reflective of their mechanism of action. However, the degree to which transcriptomic responses are conserved across different test methodologies has seldom been explored. With increasing regulatory demand for New Approach Methods (NAMs) that use alternatives to animal models and high‐content approaches such as transcriptomics, this type of comparative analysis is needed. We examined whether common genes are dysregulated in Japanese quail (Coturnix japonica) liver following sublethal exposure to the flame retardant hexabromocyclododecane (HBCD), when life stage and test methodologies differ. The four exposure scenarios included one NAM: Study 1—early‐life stage (ELS) exposure via a single egg injection, and three more traditional approaches; Study 2—adult exposure using a single oral gavage; Study 3—ELS exposure via maternal deposition after adults were exposed through their diet for 7 weeks; and Study 4—ELS exposure via maternal deposition and re‐exposure of nestlings through their diet for 17 weeks. The total number of differentially expressed genes (DEGs) detected in each study was variable (Study 1, 550; Study 2, 192; Study 3, 1; Study 4, 3) with only 19 DEGs shared between Studies 1 and 2. Factors contributing to this lack of concordance are discussed and include differences in dose, but also quail strain, exposure route, sampling time, and HBCD stereoisomer composition. The results provide a detailed overview of the transcriptomic responses to HBCD at different life stages and routes of exposure in a model avian species and highlight certain challenges and limits of comparing transcriptomics across different test methodologies. Environ Toxicol Chem 2024;00:1–11. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Legacy brominated flame retardants, including polybrominated diphenyl ethers (PBDEs), have been classified as persistent organic pollutants and replaced with novel brominated flame retardants (NBFRs). The octanol–water partition coefficients (log KOW) of NBFRs have been computationally estimated, but the log KOW values provided by these methods can differ by 1 to 3 orders of magnitude. Given the importance of this parameter in fate and toxicity models, we indirectly measured the log KOW values of eight NBFRs by their capacity factor (k′) on a reversed‐phase high‐performance liquid chromatography (HPLC) C18 column by isocratic elution and compared these measured values with those estimated by nine computational models. Log KOW values were obtained for the NBFRs 1,2‐bis(2,4,6‐tribromophenoxy) ethane, pentabromobenzene, pentabromoethylbenzene, pentabromotoluene, 2‐ethylhexyl 2,3,4,5‐tetrabromobenzoate, allyl 2,4,6‐tribromophenylether, 2,3‐dibromopropyl‐2,4,6‐tribromophenyl ether, and bis(2‐ethylhexyl) tetrabromophthalate. A training set of phthalates, polychlorinated biphenyls, PBDEs, and halogenated benzenes were chosen to obtain the log k′–log KOW calibration for the NBFRs. The computational models KowWIN, XLogP3, EAS‐E Suite, COSMOtherm, DirectML, and Abraham polyparameter linear free energy relationships all predicted the log KOW values of the calibration compounds to within 1 order of magnitude without significant bias. The median of these models predicted log KOW values for the calibration compounds that were close to those known in the literature with root mean square error (RMSE) = 0.224 and for the NBFRs that were close to those measured by HPLC (RMSE = 0.334). Environ Toxicol Chem 2024;00:1–10. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Carbon fiber (CF)‐reinforced epoxy resin (EP) composites are lightweight materials with excellent comprehensive performance. However, the flammability of EP and the poor interfacial bonding between CF and EP are two key disadvantages that limit their further applications. Here, a kind of water‐soluble lignin‐based CF sizing agent (ELBEDK) is prepared through hydrophilic modification of enzymatic lignin, which can significantly enhance the interfacial interaction between CF and EP. Additionally, a highly efficient intumescent flame retardant (LMA) is prepared. The EP, enzymatic lignin, LMA and CF sized ELBEDK are compounded to obtain the fire‐safety CF reinforced composites (SCF/FEP/L). The flame retardancy of SCF/FEP/L with 7% LMA (SCF/FEP7) reached V‐0 rating. Moreover, SCF/FEP/L with 7% LMA and 15% lignin (SCF/FEP7/L15) present an limiting oxygen index (LOI)of 30.2% and V‐0 of UL‐94. Specifically, the total smoke production and the heat release rate are 47.8% and 46.81% lower than that of SCF/EP, respectively, indicating the improved smoke suppression and flame retardancy. The IFSS and flexural strength of SCF/FEP7/L15 are improved to be 59.4 MPa and 511.1 MPa, respectively. This study presents a simple approach to fabricate low‐cost high performance lignin‐based flame retardant CF/EP biocomposites with wide application potential. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries (LIBs) are currently the predominant energy storage power source. However, the urgent issues of enhancing electrochemical performance, prolonging lifetime, preventing thermal runaway‐caused fires, and intelligent application are obstacles to their applications. Herein, bio‐inspired electrodes owning spatiotemporal management of self‐healing, fast ion transport, fire‐extinguishing, thermoresponsive switching, recycling, and flexibility are overviewed comprehensively, showing great promising potentials in practical application due to the significantly enhanced durability and thermal safety of LIBs. Taking advantage of the self‐healing core–shell structures, binders, capsules, or liquid metal alloys, these electrodes can maintain the mechanical integrity during the lithiation–delithiation cycling. After the incorporation of fire‐extinguishing binders, current collectors, or capsules, flame retardants can be released spatiotemporally during thermal runaway to ensure safety. Thermoresponsive switching electrodes are also constructed though adding thermally responsive components, which can rapidly switch LIB off under abnormal conditions and resume their functions quickly when normal operating conditions return. Finally, the challenges of bio‐inspired electrode designs are presented to optimize the spatiotemporal management of LIBs. It is anticipated that the proposed electrodes with spatiotemporal management will not only promote industrial application, but also strengthen the fundamental research of bionics in energy storage. [ABSTRACT FROM AUTHOR]

In order to obtain an efficient flame retardant and smoke suppressor without sacrificing mechanical properties of epoxy resin (EP). A cyano group‐containing 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) derivative (CP‐DOPO) was proposed and synthesized through one‐step Atherton–Todd reaction between DOPO and 4‐cyanophenol. The comprehensive performance analysis of CP‐DOPO‐based EP composite was conducted by measuring the flame retardancy, smoke suppression, and mechanical properties. The flame‐retardant test findings shows that the EP/4CP‐DOPO sample achieves UL‐94 V‐0 rating with 4 wt% low addition of CP‐DOPO. Moreover, EP/6CP‐DOPO sample presents a LOI of 36.5%, a 28.1% reduction in the peak heat release rate, and a 42.1% substantial decrease in total smoke production, demonstrating its desirable flame retardancy and smoke suppression properties. Significantly, different from the traditionally additive flame retardants, the mechanical properties of EP matrix will not be affected by the incorporation of CP‐DOPO but a 17.7% increasement of flexural properties compared to EP. This research not only provides an ingenious strategy for designing and preparing high‐effective flame retardant but also enhances the comprehensive performance of EP resins in practical applications. [ABSTRACT FROM AUTHOR]

With the advantages of lightweight and low thermal conductivity properties, polymeric foams are widely employed as thermal insulation materials for energy‐saving buildings but suffer from inherent flammability. Flame‐retardant coatings hold great promise for improving the fire safety of these foams without deteriorating the mechanical‐physical properties of the foam. In this work, four kinds of sulfur‐based flame‐retardant copolymers are synthesized via a facile radical copolymerization. The sulfur‐containing monomers serve as flame‐retardant agents including vinyl sulfonic acid sodium (SPS), ethylene sulfonic acid sodium (VS), and sodium p‐styrene sulfonate (VSS). Additionally, 2‐hydroxyethyl acrylate (HEA) and 4‐hydroxybutyl acrylate are employed to enable a strong interface adhesion with polymeric foams through interfacial H‐bonding. By using as‐synthesized waterborne flame‐retardant polymeric coating with a thickness of 600 µm, the coated polyurethane foam (PUF) can achieve a desired V‐0 rating during the vertical burning test with a high limiting oxygen index (LOI) of >31.5 vol%. By comparing these sulfur‐containing polymeric fire‐retardant coatings, poly(VS‐co‐HEA) coated PUF demonstrates the best interface adhesion capability and flame‐retardant performance, with the lowest peak heat release rate of 166 kW m−2 and the highest LOI of 36.4 vol%. This work provides new avenues for the design and performance optimization of advanced fire‐retardant polymeric coatings. [ABSTRACT FROM AUTHOR]

Melamine‐formaldehyde (MF) foam, while intrinsically flame retardant, necessitates further refinement to meet stringent fire safety standards, particularly in terms of heat release rate and thermal stability. In this study, an innovative approach was adopted wherein an inorganic substance, potassium water glass (WG), was employed to create an encapsulation layer on the surface of the MF foam structure via a straightforward dip‐coating technique. The composite foam underwent a comprehensive analysis of its structure and flame retardant characteristics, using test evaluations such as micro‐scale combustion calorimeter (MCC) testing, cone calorimeter testing (CCT), and thermogravimetric‐Fourier infrared spectrometer (TG‐IR) assessments. It was found that the even coating of WG on the MF foam surface profoundly enhanced the foam's structural integrity. Utilizing the shielding properties of this inorganic layer, the hybrid foam's thermal stability experiences a remarkable augmentation. The peak of heat release rate (pHRR) and the total heat release rate (THR) of the MF foam experienced an impressive reduction of 85.2% and 78.8%, correspondingly. Notably, this advancement is concomitant with a substantial decrease of 39.2% in the total smoke release (TSR) and a notable amelioration in mechanical characteristics. Such developments undeniably broaden their application horizons across diverse domains. [ABSTRACT FROM AUTHOR]

Among the various fire‐retardants (FRs) known, phosphorus is vital to the development of effective FRs due to its flexibility. Additionally, the additives and combinations of phosphorus with various multicomponent moieties (e. g. P−Si, P−P, P−B, etc.) can serve the purpose in different phases to improve flame retardance properties. With an increased cognizance of recyclable, eco‐friendly, and bio‐based materials, phosphine oxide‐based materials/coatings can fulfill the criteria for flawless and future FRs. In this regard, the present review highlights the most promising organophosphorus‐based compositions as non‐intrusive FRs. The classification, synthetic methods, related mechanisms, and high‐end FR applications of various recently developed organophosphorus‐based molecules and materials are demonstrated. Among various organophosphorus compounds, the phosphorus‐based polyurethane materials display remarkable FR properties and non‐toxic behavior. Notably, the flame retardance of the epoxy resins is enhanced significantly with the presence of more P=O bonds and amino groups. The limitations and advantages of organophosphorus‐based materials are compared with the traditional FRs. Also, the challenges persisting in improving current flame‐retardant materials need to be addressed. However, the success of these materials and treatment methods strongly depends on the ability to impart desired functionality, durability, and scalability without compromising environmental problems. [ABSTRACT FROM AUTHOR]

The systematic transfer of solvent‐free, additive flame retardant (FR) formulations from epoxy resins to glass fiber‐reinforced epoxy composites (GFRECs) through prepregs is difficult. Additionally, obtaining data on their post‐fire mechanics is often challenging. Utilizing melamine polyphosphate (MPP), ammonium polyphosphate (APP), and silane‐coated ammonium polyphosphate (SiAPP) FRs with low‐melting inorganic silicates (InSi) in an 8:2 proportion and 10% loading by weight in a diglycidyl ether of bisphenol A (DGEBA) resin, a systematic investigation of the processing properties, room‐temperature mechanics, and temperature‐based mechanics of the systems was performed. The resin was cured with a dicyandiamide hardener (DICY) and a urone accelerator. The results revealed no substantial impact of these FRs at the current loading on the resin's glass transition temperature or processability. However, the fire residues from cone calorimetry tests of the composites containing FRs were found to be only 15‐20% of the thickness of the resins, implying a suppression of intumescence upon transfer. At room temperature, the decrease in the flexural modulus for the composites containing FRs was negligible. Exposure of the composites in a furnace at 400°C as a preliminary study before ignition tests was shown to cause significant flexural moduli reductions after 2.5 min of exposure and complete delamination after 3 min making further testing unviable. This study emphasizes the need for future research on recovering modes of action upon transfer of FR formulations from resins to composites. Based on the challenges outlined in this investigation, sample adaptation methods for post‐fire analysis will be developed in a future study. Highlights: Processibility of resins for prepreg production unaffected by polyphosphate/inorganic silicate flame retardants (FRs).FR formulations had a negligible effect on the mechanics of the composites.15%–25% increase in the fracture toughness of the DGEBA‐based resin matrix with FRs.Suppression of intumescent behavior in the composites verified quantitatively.Significant reduction in flexural moduli of the composites post‐400°C exposure in a furnace. [ABSTRACT FROM AUTHOR]

Although cotton is the most common polymer in daily life, its limited use is due to its propensity to catch fire. To solve this issue, we developed an innovative flame‐retardant aluminum phosphate‐supported, chitosan‐linked expandable graphite composite (CAlPEG). The CAlPEG was synthesized by the reaction of natural graphite, aluminum phosphate, and chitosan biopolymer in a one‐pot method. When CAlPEG was coated with cotton fabric and exposed to continuous flame, the fabric did not catch fire up to 760 s, whereas only expandable graphite (EG), aluminum phosphate (AIP), and CS, coated cotton fabric burned within 20 s. Flame‐retardant proficiency of CAlPEG‐coated cloth was confirmed by flame tests such as a limiting oxygen index (LOI) and vertical flammability test. The blank cotton has 17% LOI and is completely burnt out. On the other hand, the as‐prepared composite has a 43% LOI rating, which denotes a high level of flame retardancy. The VFT test result showed the formation of a 3 cm char, which confirms the flame‐retardant material possesses self‐extinguishing qualities. The article develops a new method for utilizing bioresources such as chitosan and offers fresh perspectives on the environmentally friendly synthesis of phosphorylated EG‐linked chitosan on the AlPO4 matrix. [ABSTRACT FROM AUTHOR]

Ammonium polyphosphate (APP) is often used to construct intumescent flame retardant systems together, but it is faced with the problem of adding too much flame retardant. This paper envisions the construction of a modified APP flame retardant (TR@ZIFAPP) with a sandwich structure by the method of covering, which, in order to endow APP flame retardant with better flame retardant effect. By constructing a metal catalytic layer and a triazine carbon formation layer, the modified APP flame retardant has both catalytic carbon formation and phosphorus–nitrogen synergistic flame retardant functions. TR@ZIFAPP is expected to be used in flame‐retardant polymer composites with low addition requirements, adding it to epoxy resin (EP) reveals that the TR@ZIFAPP flame retardant could achieve the optimal flame retardant effect when the addition amount was only 3 wt%. The UL‐94 rating reached V‐0 grade, and the two off‐fire auto‐ignition time levels were only 0.7 s. The analysis of its flame retardant mechanism showed that the flame retardant in EP was mainly through the rapid formation of carbon to isolate oxygen and dilute the flammable gas to reach a strong flame retardant effect. [ABSTRACT FROM AUTHOR]

In previous studies, the effect of cell structures of polypropylene (PP) foam materials on flammability behavior had been largely overlooked. In this work, ammonium polyphosphate and pentaerythritol were used as intumescent flame retardants (IFR) for PP, and then the PP‐IFR flame retardant foams were prepared by using injection foaming technology with two different weight reduction methods (same mold volume before foaming and after foaming). The results showed that the average cell size of all the PP‐IFR flame retardant foams in the 10% to 30% weight reduction was less than 100 μm. The PP‐IFR flame retardant foams with an average cell diameter of 26.22 μm and cell density of 7.88 × 106 cells/cm3 had the best limiting oxygen index (LOI) of 27.9%. In addition, the PP‐IFR flame retardant foams with better foaming quality had a higher LOI and a denser foam carbon layer whatever the weight reduction methods, resulting in better flame retardant properties. The escape of gases from the foamed and un‐foamed areas not only reduced the concentration of flammable gases but also led to the collapse and rupture of the foam carbon layer during the combustion process. Hence, it provides guidance for preparing PP foam materials with excellent flame retardancy. [ABSTRACT FROM AUTHOR]

Currently, epoxy resin (EP) is widely used in various fields, but its flammability greatly limits the wider application of EP. In recent years, additive flame retardants have been widely used to enhance the flame retardancy of EPs, but poor resistance to weather and aging is a prevalent issue encountered with additive flame retardants. To improve the weather fastness, researchers have successfully created and synthesized EP molecules that possess a combined effect of P, N, and B. The results demonstrate a significant enhancement in the mechanical properties of materials containing 20% BVN/10% VPD/EP compared with those of pure EP. 20% BVN/20% VPD/EP exhibited a vertical combustion rating of V‐1 with a limiting oxygen index measuring at 29.8%. The flame retardant epoxy thermosets exhibited a notable decrease in both the maximum heat release rate and total heat release. The findings indicate that the inherent flame‐retardant properties of the P‐N‐B coacting EP are not only characterized by exceptional curing and flame retardancy but also by superior resistance to weathering and aging compared with the additive flame retardant. [ABSTRACT FROM AUTHOR]

Highlights 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. 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]

In this work, the flame retardant ISA-APP, obtained by modification of ammonium polyphosphate (APP) with isopropanolamine (ISA), was employed in epoxy resins (EP) in an attempt to enhance the fire resistance of EP. The findings indicate that, with an incorporation of 20 wt% ISA-APP in the EP, the limiting oxygen index (LOI) of EP/ISA-APP attains 33.5%, accompanied by a UL94 test V-0 rating. This performance surpasses the flame retardancy observed in EP/APP composites at equivalent content. The outcomes derived from the cone calorimeter test (CCT) demonstrate that EP/ISA-APP significantly suppresses the release of heat, generation of smoke, and emission of noxious gas during EP/ISA-APP combustion. The peak-heat release rate (pHRR) and total heat release (THR) of EP/ISA-APP are decreased by 74.4% and 63.6%, respectively, compared to pure EP. Further analysis of the char residues of EP/ISA-APP shows that the P-O-C structure generated during combustion effectively contributes to a high-quality char layer formation. This investigation presents a viable approach for enhancing flame retardant and economic benefits of APP and advancing the development of highly effective flame retardants. [ABSTRACT FROM AUTHOR]

To develop a highly efficient flame retardant system for polyurethane microbubble elastomer (PME), a phosphate-based ionic liquid (IL) 1-methyl3-(dioxyphosphoryl)-propyl imidazole bromide was synthesized, and then combined with ammonium polyphosphate (APP) and aluminum hypophosphate (ALHP) to form a ternary flame retardant system, which shows excellent synergistic flame retardancy and plays an important role in both gas phase and condensed phase flame retardancy. Compared with pure PME, the limiting oxygen index of flame retardant PME with 6 wt% IL and 15 wt% APP/ALHP increased from 20.25% to 29.25%, the char yields is increased by 13 times, and the heat release rate, total heat release rate, mass loss rate, and smoke production rate are reduced by 74%, 19%, 67%, and 22%, respectively. Ignition time increased from 9 s to 19 s, and extinguishing time increased from 295 s to 573 s. At the same time, the addition of IL promoted the dispersion and compatibility of APP/ALHP in the PME matrix and improved the mechanical properties. In addition, IL also shows potential in antistatic modification, providing the possibility for materials to meet both flame retardant and antistatic requirements. [ABSTRACT FROM AUTHOR]

High safety and stability in batteries are crucial factors for the large‐scale application of lithium‐ion technology. In this work, flame‐retardant aluminum diethylphosphonite (ADP) is coated by urea‐formaldehyde (UF) shell to conquer the side reactions caused by ADP during cycling process. And then the core@shell structured ADP@UF is combined with poly(ethylene oxide) (PEO), high thermal stability can be realized. When exposed to high temperatures, ADP@UF generates N⋅ and P⋅ radicals to eliminate the combustion the H⋅ and OH⋅ radical, to inhibit fire. By controlling the percentage of flame retardant added, PEO‐ADP@UF has totally achieved the effect of inflaming retarding, realizing stable electrochemical properties at the same time. The −NH2 in UF forms hydrogen bonds with PEO, and acts as a Lewis base to promote the dissociation of lithium salts to increase the lithium‐ion mobility number. Compared to PEO, battery with PEO‐ADP@UF has outstanding cycling performance (103 mAh g−1 at 1 C, 2.5–4.2 V) and long service life (800 cycles). [ABSTRACT FROM AUTHOR]

This study aims to investigate the flame retardancy and mechanical properties of polypropylene (PP)‐based intumescent flame retardants (IFRs) consisting of melamine phosphate (MP) and pentaerythritol (PER), and different additives; boron phosphate (BP), antimony oxide (AO), and preceramic polymers, namely poly(dimethylsilane) (PDMS) and poly(methylsilsesquioxane) (PMSQ). The composites were produced by twin‐screw extrusion, and then molded by injection molding. Their characterizations were performed with limiting oxygen index (LOI), horizontal burning tests, thermogravimetric analysis (TGA), tensile and impact tests. The total amount of IFRs and the additives in polypropylene was kept constant at 20 wt%. The additive concentration was varied as 1, 3, and 5 wt% in the composites. The highest LOI value of 29% was obtained for PP/MP/PER composite with MP/PER ratio of 3/1. PP/IFR‐based composites with 1 wt% additive exhibited higher LOI and horizontal burning performance than the other composites with 3 and 5 wt% additives. It is revealed that tensile modulus and impact strength of neat PP were improved with the addition of IFRs, and for each type and amount of the additives used in the study. Highlights: Usage of IFRs, preceramic polymers, BP and AO in PP improved flame retardancy.Lower amount of additives (1%) in PP/IFR composites led to higher LOI values.Additive incorporation enhanced tensile modulus and impact strength of neat PP. [ABSTRACT FROM AUTHOR]

The recycled nylon (RN)‐based biocomposites were fabricated by adding 25% lignin biocarbon. Lignin was pyrolyzed at 300, 600, and 900°C to produce Lig300, Lig600, and Lig900 biocarbon (BioC) samples, respectively. Higher functionality of Lig600 (unlike Lig900) allowed for improved interfacial interaction with the polar nylon matrix. Mechanical properties were further enhanced for RN_Lig600 composite with enhanced flexural and tensile strength by 18% and 8%, respectively, compared to neat polymer (RN). RN_Lig900 composite showed enhancement in tensile and flexural modulus by 32.6% and 51.1%, respectively, compared to RN. Incorporation of Lig900 in RN matrix resulted in 77.9% reduction in burning rate compared to RN. These results show the potential of lignin BioC as a filler in RN composites for flame retardant applications and mechanical enhancement, such as in the automotive industry. Highlights: Effect of pyrolysis temperatures (300, 600, and 900°C) on lignin biomass.Composites prepared from recycled polyamide 6 from carpet waste and biocarbon.Improved interfacial adhesion of 600°C biocarbon with recycled nylon matrix.Enhanced thermal, mechanical properties, reduced flammability of biocomposites.Sustainable biocomposites with 900°C biocarbon reduced burning rate by 78%. [ABSTRACT FROM AUTHOR]

Triphenyl phosphate (TPhP) is an organophosphate flame retardant and plasticizer that is added to a wide variety of consumer and industrial products. It is also a ubiquitous environmental pollutant. Exposure to TPhP has been shown to alter gene expression in metabolic and estrogenic signaling pathways in in vitro and in vivo models of a variety of species, and as such, is considered to be an endocrine disrupting chemical. Exposure to endocrine disrupting chemicals is increasingly being associated with changes to the epigenome, especially during embryonic development. The aim of this study was to evaluate whether TPhP exposure in aquatic ecosystems has the ability to alter the epigenome in two immortal cell lines derived from trout (Oncorhynchus mykiss). This study assessed whether 24 h exposure to TPhP resulted in changes to histone modification and DNA methylation profiles in steelhead trout embryonic cells and rainbow trout gill epithelial cells. Results show that several epigenetic modifications on histone H3 and DNA methylation are altered in the embryonic cells following TPhP exposure, but not in the gill epithelial cells. Specifically, histone H3 acetylation, histone H3 mono‐methylation and global DNA methylation were found to be reduced. The alterations of these epigenetic modification profiles in the embryonic cells suggest that exposure to TPhP during fetal development may alter gene expression in the developing embryo, likely in metabolic and estrogenic pathways. The impacts to the epigenome determined in this study may even carry multigenerational detrimental effects on human and ecosystem health, which requires further investigation. Triphenyl phosphate (TPhP) is an organophosphate flame retardant, ubiquitous environmental pollutant and endocrine disrupting chemical. This study evaluated whether TPhP exposure caused changes to posttranslational histone modifications and DNA methylation profiles in steelhead trout embryonic cells and rainbow trout gill epithelial cells. Histone H3 acetylation, histone H3 mono‐methylation and global DNA methylation were reduced in TPhP‐exposed embryonic cells but not gill epithelial cells. Results suggest that exposure to TPhP during fetal development may alter gene expression in the developing embryo. [ABSTRACT FROM AUTHOR]

Struvite precipitation is an efficient approach to recover phosphorus and ammonium from wastewater to alleviate many operational as well as environmental issues. The sparingly soluble nature of struvite in water makes it a potential slow‐release fertilizer whose adequacy has been investigated in various soil‐based cultivation. However, struvite has diverse applications other than field usage which are yet to be explored. The review highlights the usage of struvite as a fertilizer in soil along with its other applications as a nutrient supplier in hydroponic systems, fire retardants, and sorbent for the adsorption of heavy metals, dye, and gases. The research gaps between the lab and the application of the struvite products in the market for its proper utilization have also been reported. Thus, struvite produced from wastewater can be a promising green chemistry that could replace many costly, synthetic, and harmful products, while conserving phosphorous resource at the same time. This article is categorized under:Climate and Environment > Circular EconomyEmerging Technologies > MaterialsSustainable Development > Goals [ABSTRACT FROM AUTHOR]