Search

[Display omitted] • The multifunctional additive HCCP-TMP was innovatively synthesized by combining the free radical trapping unit—hindered amine with the high-efficiency flame retardant element—HCCP. • HCCP-TMP significantly increased the upper limit of electrochemical window of the polyacrylate gel electrolyte, improving the compatibility with the nickel-rich high-voltage cathode NCM811. • The addition of HCCP-TMP significantly improved the cycling stability and rate performance of the polyacrylate gel electrolyte at high voltages. • 1 wt% HCCP-TMP can make the polyacrylate-based gel electrolyte non-flammable, and the equipped NCM811//graphite pouch battery will not exhibit fire behavior during thermal runaway, improving the fire safety of the battery. For high energy density lithium-ion batteries (LIBs) with nickel-rich ternary cathodes, the chemical degradation of electrolytes caused by free radical reactions and the hazards of thermal runaway have always been significant challenges. Inspired by the free radical scavenging of living organisms and multiphase synergistic flame retardant mechanism, we innovatively designed and prepared a multifunctional flame retardant HCCP-TMP that combines flame retardancy and free radical scavenging by combining hindered amine and cyclophosphazene. Only 1 wt% HCCP-TMP can make the polyacrylate-based gel polymer electrolyte (GPE) incombustible. Moreover, the equipped NCM811//Graphite pouch cells don't exhibit combustion behavior after thermal runaway and can resist mechanical abuse. Based on the above noncombustible GPE, the NCM811//Li battery exhibits capacity retention rate of 82.2 % after 100 cycles at a current density of 2 C and in the voltage range of 3.0–4.7 V, exhibiting excellent cyclability under high voltage. This simple molecular design simultaneously improves the fire safety and high voltage stability, demonstrating enormous application potential in the field of advanced LIBs with high safety and high energy density. [ABSTRACT FROM AUTHOR]

The development of high toughness as well as flame‐retardant polylactic acid (PLA) materials is important for expanding the practical applications. Herein, a type of high toughness PLA composites with improved flame retardancy was developed through combining modified carbon nanotubes (CNT) and polysiliconoxaborane (PBSi) with PLA matrix. The optimal PLA composite (PLA/PBSi/CNT‐3.0) exhibited excellent crystallization degree (18.7%), thermal stability (the Ea significantly increased), flame retardancy (the values of peak heat release rate (PHRR) polarized optical microscopy and total heat release (THR) decreased to 287.1 W/g and 15.5 kJ/m2, respectively), and mechanical properties (the elongation at break increased to 149.5%, with an increasement of 1745.7%) due to the combined action of flexible chain segments and hydrogen bonding interactions. Furthermore, the toughening mechanism of the PLA/PBSi/CNT composites was illustrated and attributed to the combination of flexible SiOBO segments and two dominant energy dissipation processes (the breakage of hydrogen bond and the destruction of microcrystals). Overall, this work provided a facile approach for improving the toughness and flame retardancy of PLA, which was conducive to expanding the application range of PLA. [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]

The application of warm-mix flame retardant rubber asphalt (WFRA) in tunnel pavement offers a promising solution that enhances both energy conservation and tunnel safety. First, a commercial halogen-free flame retardant (ZK), alumina trihydrate (ATH), and organic montmorillonite compound ATH flame retardant (OMMT/ATH) were melt-blended with warm-mix rubber asphalt (WRA) to prepare different types of WFRAs. Then, the effects of various flame retardants (FRs) on flame retardancy and rheological properties of the WRA were evaluated. Moreover, the functional groups of FR, WRA, and WFRA were investigated. Finally, the synergistic mechanism of FR on the WRA was explored based on the analysis of flame retardancy, rheological properties, and functional groups. Results show that the flame-retardant effect of OMMT/ATH on the WRA is much better than that of single FRs (ZK and ATH), indicating that the OMMT and ATH exhibit synergistic flame-retardant effect. The addition of OMMT/ATH enhances the high-temperature performance but shows little effect on the fatigue performance of the WRA. The synergistic flame-retardant mechanism of OMMT/ATH on the WRA is mainly attributed to the physical barrier effect of OMMT, the cooling and dilution effect of ATH, and the synergistic covering layer effect of OMMT and ATH. [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]

Due to its excellent durability and steady mechanical qualities, three‐dimensional porous polyurethane foam (PUF) presents a wide range of possibilities for flexible piezoresistive sensors. Its extreme flammability, poor electrical conductivity, and susceptibility to outside factors present serious difficulties, though. In this study, a waterborne polyurethane‐coated flexible PUF sensor that incorporates reduced graphene oxide (RGO) and polyaniline (PANI) through a methodical, step‐by‐step dip‐coating methodology is successfully developed. The final product has a water contact angle of 133°, which improves its ability to adapt to a variety of environmental circumstances. Flexible graphene sheets are incorporated to improve heat resistance and flame retardancy, and PANI and RGO provide strong bonding to the PUF framework, ensuring outstanding structural stability even after 1500 cycles. The flexible foam sensor shows promise for use in flexible piezoresistive sensors and electronic skin due to its remarkable strain monitoring range of up to 70%, quick response time of 0.39 s in sensitivity experiments, and adaptability to different physical activities like walking and gesturing. [ABSTRACT FROM AUTHOR]

A large amount of toxic smoke and heat generated by the combustion of ethylene vinyl acetate copolymer (EVA) poses a significant threat to human fire escape evacuation. This work aims to use γ -ray to prepare e-MXene@Ag hybrid flame-retardant materials by the method of in-situ reduction, and EVA composites are prepared by melt blending to reduce the smoke and toxic gases produced during combustion significantly. Compared with pure EVA, the total heat release, total smoke release, and the production rate of CO and CO2 produced by the combustion of EVA composite with 1 wt% e-MXene@Ag1.0 decreased by 30.3%, 33.3%, 18.2%, and 20.1% respectively. The fire hazard reduction of EVA composite materials was due to the physical barrier, catalytic carbonization and adsorption of the e-MXene@Ag1.0 hybrid. In addition, e-MXene@Ag1.0 can also further increase the mechanical properties of EVA composites due to its own 'multi-contact point limit structure'. [ABSTRACT FROM AUTHOR]

Intumescent fire-retardant coatings, which feature thinner layers and good decorative effects while significantly reducing heat transfer and air dispersion capabilities, are highly attractive for fire safety applications due to their effective prevention of material combustion and protection of materials. Particularly, the worldwide demand for improved environmental protection requirements has given rise to the production of waterborne intumescent fire-retardant polymer composite coatings, which are comparable to or provide more advantages than solvent-based intumescent fire-retardant polymer composite coatings in terms of low cost, reduced odor, and minimal environmental and health hazards. However, there is still a lack of a comprehensive and in-depth overview of waterborne intumescent fire-retardant polymer composite coatings. This review aims to systematically and comprehensively discuss the composition, the flame retardant and heat insulation mechanisms, and the practical applications of waterborne intumescent fire-retardant polymer composite coatings. Finally, some key challenges associated with waterborne intumescent fire-retardant polymer composite coatings are highlighted, following which future perspectives and opportunities are proposed. [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]

This study aimed to improve the flame retardancy and mechanical properties of bacterial cellulose (BC) by introducing cereal proteins, namely zein and gluten. The production conditions were determined by observing residual masses of samples at 1000 ℃ using thermogravimetric analysis (TGA). According to the TGA results, the optimized production conditions for the BCs with zein and gluten were combined solvent exchange and entrapment of 20 weight% (wt.%) of zein, and entrapment of 40 wt.% of gluten, respectively. Surface characterization of BC prepared with zein and gluten under the optimal conditions confirmed that the cereal proteins were incorporated into the BC nanostructures via solvent exchange and/or entrapment and the original chemical and crystal structures of BC were not significantly changed. Limiting oxygen index (LOI) analysis confirmed that cereal proteins improved the flame retardancy of BC. In particular, the LOI of BC entrapped with gluten was 50%, which was better than that of cowhide leather. Char morphology analysis confirmed that the as-produced BCs with cereal proteins exhibited condensed-phase flame-retardant mechanism by forming intumescent chars. Analysis of the mechanical properties confirmed that compared with cowhide leather, as-produced BCs with cereal proteins possessed high tensile strength and dimensional stability, making them suitable leather substitutes. [ABSTRACT FROM AUTHOR]

The intumescent flame retardant (IFR) technique is an alternative to halogen-based flame retardants for reducing fire hazards in polymers. However, IFR has drawbacks like unsatisfactory flame-retardant efficiency and high loading requirements. In this study, MIL-125 (Ti-based metal–organic framework) is added to ABS/IFR composites to improve flame retardancy and reduce smoke emissions. Thermogravimetric analysis (TGA) results indicate that combining ammonium polyphosphate (APP) and expandable graphite (EG) increases charred residue and slows mass loss compared with the original ABS resin. The ABS/IFR/MIL-125 system stabilizes the char layer, serving as a protective shield against combustible gases during combustion. Additionally, MIL-125 enhances performance in microscale combustion calorimetry (MCC) flammability testing. In fire tests (UL-94, limiting oxygen index (LOI), and cone calorimeter), the ABS/IFR/MIL-125 system achieves a UL-94 V0 rating and the highest LOI value of 31.5% ± 0.1%. Peak heat lease rate (PHRR) values in the cone calorimeter are reduced by 72% with 20 wt.% of additives, and smoke production decreases by 53% compared with neat ABS. These results demonstrate the efficient synergistic effects of MIL-125 and IFR additives in improving the formation and stability of the intumescent char layer, thereby protecting ABS from intense burning. [ABSTRACT FROM AUTHOR]

Toughening the petroleum-based epoxy resin blends with bio-based modifiers without compromising their modulus, mechanical strength, and other properties is still a big challenge in view of the sustainability. In this study, a bio-based liquid crystal epoxy resin (THMT-EP) with an s-triazine ring structure was utilized to modify a petroleum-based bisphenol A epoxy resin (E51) with 4,4′-diaminodiphenylsulfone (DDS) as a curing agent, and the blended systems were evaluated for their thermal stability, mechanical properties, and flame retardancy. The results showed that the impact strength of the blended system initially increased and then decreased with the increase in THMT-EP content, and it reached the a maximum value of 26.5 kJ/m2 when the THMT-EP content was 5%, which was 31.2% higher than that of E51/DDS. Notably, the flexural strength, modulus, and glass transition temperature of the blended system were all simultaneously improved with the addition of THMT-EP. At the same time, the addition of THMT-EP enhanced the flame retardancy of the system by increasing the char yield at 700 °C and decreasing the peak heat release rate and total heat release rate. This work paves the way for a more sustainable improvement in the comprehensive performance of epoxy resin. [ABSTRACT FROM AUTHOR]

Pultruded fiber reinforced polymer composites used in civil, power, and offshore/marine applications use fillers as resin extenders and for process efficiency. Although the primary use of fillers is in the form of an extender and processing aid, the appropriate selection of filler can result in enhancing mechanical performance characteristics, durability, and multifunctionality. This is of special interest in structural and high voltage applications where the previous use of specific fillers has been at levels that are too low to provide these enhancements. This study investigates the use of montmorillonite organoclay fillers of three different particle sizes as substitutes for conventional CaCO3 fillers with the intent of enhancing mechanical performance and hygrothermal durability. The study investigates moisture uptake and kinetics and reveals that uptake is well described by a two-stage process that incorporates both a diffusion dominated initial phase and a second slower phase representing relaxation and deterioration. The incorporation of the organoclay particles substantially decreases uptake levels in comparison to the use of CaCO3 fillers while also enhancing stage I, diffusion, dominated stability, with the use of the 1.5 mm organoclay fillers showing as much as a 41.5% reduction in peak uptake as compared to the CaCO3 fillers at the same 20% loading level (by weight of resin). The mechanical performance was characterized using tension, flexure, and short beam shear tests. The organoclay fillers showed a significant improvement in each, albeit with differences due to particle size. Overall, the best performance after exposure to four different temperatures of immersion in deionized water was shown by the 4.8 mm organoclay filler-based E-glass/vinylester composite system, which was the only one to have less than a 50% deterioration over all characteristics after immersion for a year in deionized water at the highest temperature investigated (70 °C). The fillers not only enhance resistance to uptake but also increase tortuosity in the path, thereby decreasing the overall effect of uptake. The observations demonstrate that the use of the exfoliated organoclay particles with intercalation, which have been previously used in very low amounts, and which are known to be beneficial in relation to enhanced thermal stability, flame retardancy, and decreased flammability, provide enhanced mechanical characteristics, decreased moisture uptake, and increased hygrothermal durability when used at particle loading levels comparable to those of conventional fillers, suggesting that these novel systems could be considered for critical structural applications. [ABSTRACT FROM AUTHOR]

This paper presents recent developments in graphene‐based nanomaterial (GNM)‐containing flame‐retardant (FR) polyethylene (PE) composites for advanced applications and introduces knowledge gaps and potential solutions. Various nanomaterials have been used to improve the FR properties of PEs. Among these, GNMs score highly because of their superior performance and multifunctional characteristics. By offering a holistic overview of the fundamentals of the FR characteristics of GNMs, the processing and characterization of PE/GNM composites, and the critical aspects related to the development of FR PE/GNM composites for advanced applications, this review provides insights into advances in this area as well as prospects. Furthermore, the kinetics of the FR characteristics of PE and PE/GNM composites are critically discussed in the context of how the FR properties of PE/GNM composites can be tailored by modifying either the surface of the GNM, PE or both, an area seldom discussed in the literature. Moreover, the FR performance of PE/GNM composites is compared with PE/Expandable Graphite (EG) composites because EG has been recognized as a highly efficient and eco‐friendly intumescent FR. In summary, this review offers new insights into the design of advanced PE/GNM composites for automotive, construction, aerospace, and electronic packaging applications. [ABSTRACT FROM AUTHOR]

Epoxy sheet molding compound (ESMC) composites have excellent mechanical properties, dimensional stability and electrical insulation, and are widely used in the automotive industry. In our previous work silane coupling agent modified, hollow glass microspheres (SiHGM) and montmorillonite (MMT) were incorporated to enhance the mechanical properties of the ESMC composites. It was found that the ESMC composites containing MMT (EP/SiHGM/MMT-1) exhibited excellent mechanical strength. However, the flammability of the epoxy resin (EP) limits the use of ESMC composites for applications that require good flame retardancy. In this paper we describe our research in which MMT was used to increase the flame retardancy of ESMC composites. The results showed that the addition of MMT made the ESMC composites have excellent flame retardancy. The limiting oxygen index (LOI) of the ESMC composites containing 1 phr MMT (EP/SiHGM/MMT-1) was 26.8%, which was 8.94% higher than that of the ESMC composites without MMT (EP/SiHGM/MMT-0). In addition, the peak heat release rate (PHRR), average heat release rate (AHRR) and total heat release (THR) of the EP/SiHGM/MMT-1 were 322.8 kW/m2, 95.3 kW/m2 and 38.6 MJ/m2, respectively, which were 22.6%, 8.2% and 8.0% lower than those of EP/SiHGM/MMT-0. The carbon monoxide production (COP) and carbon dioxide production (CO2P) of EP/SiHGM/MMT-1 were 0.0092 g/s and 0.2071 g/s, respectively, which were 34.3% and 22.8% lower than those of EP/SiHGM/MMT-0. The fire growth index (FGI) of EP/SiHGM/MMT-1 was 2.4, which was a decrease by 29.4% compared to EP/SiHGM/MMT-0. In addition, the flame retardant mechanisms were revealed. We suggest that MMT promoted dehydration and charring of the epoxy resin and helped construct an intact physical barrier, which had good blocking effects. The prepared composite has great application prospects for those occasions that require high flame retardancy. Thus, this work provides an innovative strategy for preparing low density epoxy composites with excellent flame retardancy and high mechanical properties. [ABSTRACT FROM AUTHOR]

poly (p-phenylene terephthalamide) (PPTA) fiber, a new strategic material, has excellent mechanical properties, chemical corrosion resistance and flame retardant properties, and is widely used in aerospace, national defense, civil and other fields. The mechanical properties, relative molecular weight, aggregate structure and fiber surface and internal defects of four samples of para-aramid fibers were studied, and the relationship between properties, structure and defects of fibers was established. The results show that the relative molecular weight of PPTA is one of the important factors affecting the mechanical property of the fibers with the same chemical molecular structure, and the tensile strength and modulus of fibers increase with the increase of the relative molecular weight. The tensile strength of para-aramid is mainly related to its crystallinity, orientation, surface defects and internal microporous defects, among which crystallinity and micro-defects are two important factors. The fiber modulus is mainly related to its orientation, and the influence of crystallinity and fiber internal and external defects on fiber modulus is relatively small. [ABSTRACT FROM AUTHOR]

In view of the serious problem of recycling and insolubility of thermosetting resin matrix composites in automobile manufacturing, a curing agent containing dynamic imine bond was synthesized by using biovanillin and 4, 4-diaminophenylsulfone. It was further used to cure epoxy resins into a vitreous matrix for fiberglass composite that could be reprocessed and recycled. The composite shows excellent mechanical properties, with a tensile strength and modulus of 670 MPa and 29 GPa, flexural strength and modulus of 752 MPa and 27 GPa, and shear strength of 55 MPa, which are comparable to the commercial battery pack composite material such as BAC 449. This new vitrimer-based composite has better mechanical properties, and its flame retardant can reach UL-94 V-0 level. In addition, owing to the nature of dynamic imine bonds, this vitrimer-based composite can be chemically degraded so that the fiber and resin in the composite can be recycled and reused, helping with carbon reduction and environmental protection. It has potential application in the manufacturing of composite covers of battery packs for electric vehicles. [ABSTRACT FROM AUTHOR]

Plastics and composites for consumer goods often require flame retardants (FRs) to mitigate flammability risks. Finding FRs that are effective in new sustainable materials is important for bringing them to the market. This study evaluated various FRs in SunBG90 (a composite made from triglycerides and sulfur)—a high sulfur-content material (HSM) promising for use in Li–S batteries, where flame resistance is critical. SunBG90 was blended with FRs from several classes (inorganic, phosphorus-based, brominated, and nitrogen-containing) to assess compliance with UL94 Burning Test standards. Inorganic FRs showed poor flame retardancy and lower mechanical strength, while organic additives significantly improved fire resistance. The addition of 20 wt. % tetrabromobisphenol A enabled SunBG90 to achieve the highest flame retardancy rating (94V-0), while also enhancing wear resistance (52 IW, ASTM C1353) and bonding strength (26 psi, ASTM C482). Selected organic FRs also enhance compressive strength compared to the FR-free SunBG90. This research highlights the potential of HSMs with traditional FRs to meet stringent fire safety standards while preserving or enhancing the mechanical integrity of HSM composites. [ABSTRACT FROM AUTHOR]

Expandable graphite (EG) was modified with a charring agent and organic–inorganic hybridized intumescent flame retardants (MEG) were synthesized. This study uses a cone calorimeter (CCT) and a DaqPRO 5300 radiation heat flow meter (Fourtec, Tel Aviv, Israel) to evaluate the fire-resistant properties influenced by MEG on intumescent fire-retardant coatings. The impact of MEG on the thermal degradation of these coatings was investigated through the use of thermogravimetric analysis (TGA). The results obtained by CCT demonstrated that the incorporation of MEG markedly diminished the heat release rate and total heat release rate of the coating, in addition to enhancing the char residue compared to coatings with only expandable graphite (EG). Furthermore, TGA results demonstrate that adding MEG increases the weight of the char residue at elevated temperatures, suggesting improved thermal stability. Based on these findings, MEG exhibits a synergistic flame-retardant effect when combined with intumescent fire-retardant (IFR) systems. This synergy not only improves the flame-retardant properties of the coatings but also enhances their overall thermal stability, making MEG a promising additive for developing more efficient fire-retardant materials. Thus, MEG-modified coatings offer superior protection against fire hazards, highlighting their potential for practical applications in fire safety. [ABSTRACT FROM AUTHOR]

Carbon-based conductive polymer composites have attracted wide attention as candidates for high-performance flexible electric heaters. Herein, a poly(m-phenylene isophthalamide) (PMIA)/carbon black (CB) composite is proposed as electric heating films that can successfully realize stable and safe operation at high temperatures of > 200°C under a safe voltage as low as 20 V. The conductive filler content has a significant effect on the microstructure and electrical properties of the PMIA/CB composites. An optimized CB content of 20 wt.% in the PMIA polymer matrix not only guarantees uniform spatial dispersion, but also provides sufficient and stable conductive networks. As a result, the PMIA/CB composites present high heating temperature, rapid heating ability, good heating uniformity, and excellent heating reliability. Meanwhile, taking advantage of the high thermal stability, superior mechanical strength, and excellent flame retardancy of the PMIA polymer matrix, the PMIA/CB composites exhibit superior thermal endurance and self-extinguishing capabilities, leading to significantly enhanced operating safety. This study will open new avenues for the development of high-performance electrothermal composite films for medium- to high-temperature applications. [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]

Biomass has been widely used due to its environmental friendliness, sustainability, and low toxicity. In this study, aminophosphorylated cellulose (PNC), a biomass flame retardant containing phosphorus and nitrogen, was synthesized by esterification from cellulose and introduced into polyurethane to prepare flame-retardant rigid polyurethane foam. The combustion properties of the PU and PU/PNC composites were studied using the limiting oxygen index (LOI), UL-94, and cone calorimeter (CCT) methods. The thermal degradation behavior of the PU and PU/PNC composites was analyzed by thermogravimetric analysis (TGA) and thermogravimetric infrared spectroscopy (TG-IR). The char layer after combustion was characterized using SEM, Raman, and XPS. The experimental results showed that the introduction of PNC significantly improved the flame-retardant effect and safety of PU/PNC composites. Adding 15 wt% PNC to PU resulted in a vertical burning grade of V-0 and a limiting oxygen index of 23.5%. Compared to the pure sample, the residual char content of PU/PNC15 in a nitrogen atmosphere increased by 181%, and the total heat release (THR) decreased by 56.3%. A Raman analysis of the char layer after CCT combustion revealed that the ID/IG ratio of PU/PNC15 decreased from 4.11 to 3.61, indicating that the flame retardant could increase the stability of the char layer. The TG-IR results showed that PNC diluted the concentration of O2 and combustible gases by releasing inert gases such as CO2. These findings suggest that the developed PU/PNC composites have significant potential for real-world applications, particularly in industries requiring enhanced fire safety, such as construction, transportation, and electronics. The use of PNC provides an eco-friendly alternative to traditional flame retardants. This research paves the way for the development of safer, more sustainable, and environmentally friendly fire-resistant materials for a wide range of applications. [ABSTRACT FROM AUTHOR]

Nanocomposites containing impermeable two-dimensional materials are attracting considerable attention for their ability to shield metals from corrosion. Incorporating m-aminophenyltrimethoxysilane functionalized niobium nitride (NbN) into a coating matrix can bolster the barrier effect owing to its remarkable chemical and thermal stability. When integrated into graphitic carbon nitride (GCN) within polyurethane (PU), functionalized NbN enhances corrosion protection and imparts fire-retardant properties. Utilizing electrochemical techniques in chloride-rich environments, the protective efficacy of aluminum coated with polyurethane containing varying proportions of functionalized NbN/GCN was investigated. Electrochemical impedance spectroscopy measurements demonstrated improved coating resistance (Rcoat: 5.65 × 1011 Ω cm2) for PU/functionalized NbN/GCN, even after 600 h of electrolyte exposure. Furthermore, the resulting PU composite exhibited superior flame-retardant capabilities, manifesting significant reductions in peak heat release rate, total heat release, and total smoke production compared to pure PU. Featuring a water contact angle of 165°, the newly developed PU/functionalized NbN/GCN coating showcased exceptional water repellency. In terms of mechanical properties such as adhesion strength and hardness, PU/functionalized NbN/GCN demonstrated favorable characteristics within the PU substrate, maintaining structural integrity even after prolonged immersion. Consequently, the PU/functionalized NbN/GCN nanocomposite presents itself as a promising coating component for aerospace applications. [ABSTRACT FROM AUTHOR]

Polycarbonate/acrylonitrile butadiene styrene (PC/ABS) blends are widely used as engineering plastic alloys; however, they have a low fire safety level. To improve the flame-retardant property of PC/ABS, a zirconium-based metal-organic framework material (UiO-66) was synthesized with zirconium chloride and terephthalic acid and used as a flame-retardant cooperative agent. Its flame-retardant performance and mode of action in the PC/ABS blends were carefully investigated. The results showed that UiO-66 had good thermal stability and delayed the pyrolysis of the materials, thus significantly enhancing the efficiency of intumescent flame retardants. By compounding 7.0 wt% hexaphenyloxy-cyclotri-phosphazene (HPCTP) with 3.0 wt% UiO-66, the PC/ABS blends reached a limiting oxygen index value of 27.0% and V0 rating in the UL-94 test, showing significantly improved resistance to combustion dripping. In addition, UiO-66 enhanced the smoke and heat suppression characteristics of the intumescent flame-retardant materials. Finally, the flame-retardant mode of action in the blends was indicative of UiO-66 having a cooperative effect on the flame-retardant performance of PC/ABS/HPCTP materials. This work provides good ideas for further development of the flame-retardant ABS/PC. [ABSTRACT FROM AUTHOR]

The increasing global commitment to carbon neutrality has propelled a heightened focus on sustainable construction materials, with wood emerging as pivotal due to its environmental benefits. This review explores the development and application of eco-friendly polymer nanocomposite coatings to enhance wood's fire resistance, addressing a critical limitation in its widespread adoption. These nanocomposites demonstrate improved thermal stability and char formation properties by integrating nanoparticles, such as nano-clays, graphene oxide, and metal oxides, into biopolymer matrices. This significantly mitigates the flammability of wood substrates, creating a robust barrier against heat and oxygen. The review provides a comprehensive examination of these advanced coatings' synthesis, characterization, and performance. By emphasizing recent innovations and outlining future research directions, this review underscores the potential of eco-friendly polymer nanocomposite coatings as next-generation fire retardants. This advancement supports the expanded utilization of wood in sustainable construction practices and aligns with global initiatives toward achieving carbon neutrality. [ABSTRACT FROM AUTHOR]

In recent years, thermoplastic polyurethane elastomer has shown great application prospects in the fields of polymer film due to its outstanding tensile properties, high elasticity, wear resistance, oil resistance, low temperature resistance, wide range of hardness, and other properties. However, its flammable properties greatly limit its application in the field of polymer film. The self-made GO was used as a carbon source, phenylboronic acid as an acid source, ammonium polyphosphate (APP) as an acid and gas source, and intumescent flame retardant (IFR) was compounded. The IFR was introduced into thermoplastic polyurethane (TPU) to prepare a series of IFR/TPU composite films with different formulations. The results show that PA and GO can make up for the loss of mechanical properties caused by the addition of APP and improve the thermal stability of the composite film, and the IFR flame retardant composed of the two and APP can effectively improve the flame retardancy of the composite film. When the additions of APP, PA, and GO were 10, 3, and 0.75%, respectively, the LOI value of the IFR/TPU composite material reached 29.5, the flame-retardant grade reached V-0, and its peak heat release rate, total heat release, peak smoke production rate, and total smoke release were 86.0, 64.9, 70.5, and 21.7%, greatly lower than pure TPU, respectively. The flame retardancy of the spacer composite membrane constructed from Ti-7 was significantly improved, and the burn-through time of the single-layer film sample was increased by 2.22 times, and the double-layer film sample was increased by 2.63 times. [ABSTRACT FROM AUTHOR]

In order to improve the burn-through resistance and environmental friendliness of epoxy resin-based flame-retardant coatings, high-performance coatings were developed by modifying them with silicone resin and B 4 C. By incorporating B 4 C and silicone resin, the coating's thermal stability was significantly enhanced. By participating in a series of chemical reactions when the coating was exposed to fire, they promoted spontaneous ceramicized and vitrified modification, increased the mass of char residue, improved the surface compactness, optimized the foam structure, and improved the specific surface area of char residue. Compared to blank sample E10S0 and others, E85S15B3 coating co-modified with silicone resin and B 4 C showed the best performance. The backside temperature of E85S15B3 was only 164.34 °C after a 2 h combustion test. The peak heat release rate (PHRR), total heat release rate (THR), total smoke production (TSP), peak smoke production rate (PSPR), peak CO release rate (PCOPR), and peak CO 2 release rate (PCO 2 PR) of E85S15B3 were all significantly improved, with a decrease of 20.38 %, 40.06 %, 37.67 %, 49.21 %, 64.71 %, 0.03 % compared with that of E10S0 sample. The LOI value was 34.6 %, which was 48.24 % better than that of E10S0. Moreover, the compressive, tensile, and bending strengths of E85S15B3 were measured at 85.6 MPa, 25.6 MPa, and 45.3 MPa, respectively, marking a 22.1 % increase, 11.23 % increase, and 23.19 % increase over those of E10S0. The mechanism of flame-retardant includes cooling insulation, non-flammable gas-phase dilution flame retardancy, condensed phase physical insulation, reinforced-phase flame retardancy, and free radicals capturing to block combustion. [ABSTRACT FROM AUTHOR]

Bio-based materials as flame retardants meet the requirements of green strategy and sustainable development. Here nitrogen and phosphorus-modified bio-based cellulose nanocrystal composite (NPCNCs) were designed and added to epoxy resin (EP) to determine fire safety and mechanical properties. NPCNCs were successfully synthesized using ice bath polymerization and exhibited a fibrous appearance with rough surface. When corresponding into EP, NPCNCs endowed EP composite with excellent flame retardancy. For EP/6NPCNCs, the LOI value was 27.6% which was higher than that of pure EP (23.5%). Compared with pure EP, the total heat release, peak heat release rate, total smoke production and peak smoke production rate values of EP/6NPCNCs decreased by 27.27%, 43.34%, 70.21% and 66.67%. This was attributed to catalysis-dehydration and carbonization, carbon support of cellulose nanocrystals and gas phase dilution. In addition, the flame retardant EP composite mechanical properties were basically maintained compared with the pure EP. This article will provide a new way for the design bio-based P and N-modified flame retardants. [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]

Highlights: The flexible single-walled carbon nanotube/titanium carbide composite films exhibit excellent thermoelectric (TE), high-temperature stable and flame-retardant properties. The assembled TE device achieves an ultrafast fire warning response time of ~ 0.1 s with a threshold voltage of 1 mV. The fire warning device demonstrates exceptional repeatability and long-term stability. The designed intelligent system is promising for next-generation self-powered remote IoT fire warning applications. Fire warning is vital to human life, economy and ecology. However, the development of effective warning systems faces great challenges of fast response, adjustable threshold and remote detecting. Here, we propose an intelligent self-powered remote IoT fire warning system, by employing single-walled carbon nanotube/titanium carbide thermoelectric composite films. The flexible films, prepared by a convenient solution mixing, display p-type characteristic with excellent high-temperature stability, flame retardancy and TE (power factor of 239.7 ± 15.8 μW m−1 K−2) performances. The comprehensive morphology and structural analyses shed light on the underlying mechanisms. And the assembled TE devices (TEDs) exhibit fast fire warning with adjustable warning threshold voltages (1–10 mV). Excitingly, an ultrafast fire warning response time of ~ 0.1 s at 1 mV threshold voltage is achieved, rivaling many state-of-the-art systems. Furthermore, TE fire warning systems reveal outstanding stability after 50 repeated cycles and desired durability even undergoing 180 days of air exposure. Finally, a TED-based wireless intelligent fire warning system has been developed by coupling an amplifier, analog-to-digital converter and Bluetooth module. By combining TE characteristics, high-temperature stability and flame retardancy with wireless IoT signal transmission, TE-based hybrid system developed here is promising for next-generation self-powered remote IoT fire warning applications. [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]

Carbon dots (CDs) are a novel class of carbon material which have gained widespread usages owing to their exceptional optical properties, low toxicity, and high biocompatibility. The nitrogen‐doped carbon dots (N‐CDs) using a normal curing agent of 4,4′‐diaminodiphenylmethane as resource was expected to not only have good compatibility with epoxy resin (EP), but also bring luminescent property to EP composites. It was interesting that the N‐CDs‐EP composites with 12.5 wt% addition exhibited a limiting oxygen index value of 31.4% and reached UL‐94 V‐1 grade, indicating a good flame retardancy. Compared with pure EP, the incorporation of N‐CDs formed more residual char and had extra smoke suppression effect. Besides, the N‐CDs‐EP composites exhibited a low transmittance less than 10% for the light wavelength below 490 nm. The N‐CDs contributed to the light shielding capabilities of the N‐CDs‐EP composites, which could effectively shield purple, blue, and cyan light. Furthermore, the mechanical properties including bending strength and impact strength, the dielectric property, and hydrophobicity of N‐CDs‐EP composites were also improved. The simple but effective modification strategy might be expected to be applied in many polymer systems. [ABSTRACT FROM AUTHOR]

Carbonaceous materials hydrothermally produced using waste biomass have small specific surface areas (SSA) and poor porosity properties. In this study, we prepare a novel carbonaceous material with excellent porosity properties by suppressing the formation of a secondary char phase (spheres) and promoting biomass hydrolysis by controlling the hydrothermal conditions. Rice husk powders, as the starting material, are hydrothermally treated using acidic solvents of different types and concentrations at 180 °C. The surfaces of the samples hydrothermally prepared using the acidic solvents have no spheres. In the case of 0.1–0.2 mol L−1 hydrochloric acid (HA), the amorphous carbonaceous materials contain numerous mesopores and exhibit a larger SSA (approximately 100 m2 g−1) than those prepared using acetic acid and distilled water. An increase in the hydrothermal temperature reduces the porosity properties of the materials. Finally, the high-porosity amorphous carbonaceous material showed excellent trimethylamine adsorption ability. [ABSTRACT FROM AUTHOR]

Dynamic covalent chemistry is a promising strategy for developing recyclable thermosets and their carbon fiber reinforced composites, in line with the goal of green and sustainable development. However, a significant challenge lies in balancing the dynamic reversibility and the desired service performances, such as thermal, mechanical properties, and flame retardancy. It has hindered the broader application of dynamic materials beyond the initial proof of concept. This concept provides an overview of the current state of research on phosphorus‐containing covalent adaptable networks (CANs), highlighting key designing and regulating principles for tailoring comprehensive properties including flame retardancy, mechanical and thermal properties, as well as dynamic behaviours such as malleability, reprocessability and degradability. Finally, new frontiers and opportunities in developing high‐performance sustainable CANs‐based thermosets and their carbon fiber composites for structural engineering applications are prospected. [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]

Potassium‐ion batteries (PIBs) with conventional organic‐based flammable electrolytes suffer from serious safety issues with a high risk of ignition and burning especially under harsh conditions, which significantly limits their widespread applications. Flame‐retardant electrolytes (FREs) are considered as one of the most effective strategies to address these safety issues. Therefore, it's much necessary to summarize the challenges, recent progress, and design principles of flame‐retardant nonaqueous electrolytes for PIBs to guide their development and future applications. In this review, an in‐depth introduction and explanation of the origins of electrolyte flammability are first presented. Particularly, the state‐of‐the‐art design principles of FREs for PIBs are extensively summarized and emphasized, including the electrolyte flame‐retardant solvents/additives, highly concentrated electrolytes (HCEs), localized high‐concentration electrolytes (LHCEs), ionic liquids‐based electrolytes and solid‐state electrolytes. Moreover, the advantages and drawbacks of each approach are systematically presented and discussed, following by proposed perspectives to guide the rational development of next‐generation high‐safety PIBs for practical applications. [ABSTRACT FROM AUTHOR]

In this article, the optimal conditions for synthesizing a new flame retardant based on pentaerythritol, phosphoric acid, and magnesium hydroxide are studied. In this case, the molar ratio of the initial substances was 3.64:1, and the synthesis duration was four hours. After the completion of this process, different (1, 3, and 5%) solutions of magnesium hydroxide were added at a temperature of 90 ºC for 3 hours. The yield of this reaction was 85%. Applying this obtained flame retardant to textile materials increases the fire resistance of textile materials. The composition of synthesized antiperine and antiperine applied textile fabrics was studied by IR spectrum, and the thermal decomposition of antiperine applied fabric was investigated by TGA and DTA analysis, and 100 μm sections of flame retardant treated fabrics were measured by scanning electron microscope. The fire resistance and physical mechanical properties of these materials were studied based on the requirements of GOST 50810-95. The oxygen index of the fabric treated with synthesized flame retardant was 35.6%. [ABSTRACT FROM AUTHOR]

The growing requirements regarding the safety of using polymers and their composites are related to the emergence of more effective, sustainable, and hazardous-limited fire retardants (FRs). Significant amounts of FRs are usually required to effectively affect a polymer's burning behavior, while the knowledge of their recycling potential is still insufficient. At the same time, concerns are related not only to the reduced effectiveness of flame retardancy but also, above all, to the potential deterioration of mechanical properties caused by the degradation of temperature-affected additives under processing conditions. This study describes the impact of the four-time reprocessing of bio-based polyamide 11 (PA11) modified with an intumescent flame-retardant (IFR) system composed of ammonium polyphosphate (APP), melamine cyanurate (MC), and pentaerythritol (PER) and its composites containing additional short basalt fibers (BFs). Composites manufactured via twin-screw extrusion were subjected to four reprocessing cycles using injection molding. A comprehensive analysis of their structural, mechanical, and fire behavior changes in each cycle was conducted. The obtained results confirmed the safety of using the proposed fire-retarded polyamide and its composites while reprocessing under the recommended process parameters without the risk of significant changes in the structure. The partial increase in flammability of reprocessed PA-based materials caused mainly by polymer degradation has been described. [ABSTRACT FROM AUTHOR]

A series of borosiloxane structures-containing polybenzoxazines (PBZs) with intrinsic environment-friendly flame-retardant properties and high-temperature resistance are investigated in this study. Initially, borosiloxane structures-containing benzoxazine macromonomers (BZ-BSiO-X) were synthesized through a condensation reaction between silicon ethoxy groups-containing benzoxazine monomers (P-mdes), boric acid (BA) and diphenyldimethoxysilane (DPDMS) with varying feed ratios. Subsequently, the benzoxazine groups in BZ-BSiO-X underwent ring-opening polymerization at elevated temperatures to produce poly(BZ-BSiO-X). The properties of poly(BZ-BSiO-X) were evaluated using Dynamic Mechanical Analysis, Thermogravimetric Analysis and an Oxygen Index instrument. The results show that the heat resistance of poly(BZ-BSiO-X) is enhanced by the cross-linking structures formed by the P-mdes segment and B-N coordination interaction, leading to their glass transition temperatures (Tg, tan δ) exceeding 300 °C. The thermal stability and flame-retardant properties of poly(BZ-BSiO-X) are reinforced via the borosiloxane structures formed through DPDMS and BA, resulting in a 5% weight loss temperatures (Td5) around 400 °C and limiting oxygen index (LOI) values above 30. These polymers, containing environment-friendly flame-retardant boron (B) and silicon (Si) elements, exhibit potential as alternatives to halogen- or phosphorus-containing flame-retardant materials and are expected to be used in various fields as environment-friendly flame-retardant materials. [ABSTRACT FROM AUTHOR]

A new fire retardency APD was synthesized successfully by the condensation between 2‐aminopyrazine and DOPO, and target product APD was characterized by NMR. Absorption peak at 12.6 ppm in 31P NMR verified complete consumption of the reactant DOPO and further confirmed the structure of APD. The safety of epoxy resin (EP) in fire disaster was dramatically improved by introduction of APD. Epoxy resin modified with 8% APD succeeded in vertical burning (UL‐94) test with V‐0 rating and limited oxygen index (LOI) of EP/8% APD was also improved to 33.9%. Cone calorimeter (CC) test further exhibited fire resistant effect of APD on EP in detail. 11.0 g APD reduced total heat release of 100 g EP to 35.1% and reduced total smoke product of 100 g EP to 19.9%. Char residue from CC test of EP/8% APD was analyzed by Raman, XPS, SEM, and FTIR tests. The results of these tests indicated that compact morphology of char residue from EP/8% APD possessed a positive effect in blocking fire spread. Highlights: APD was synthesized and fire resistant EP was made.EP/APD acquired outstanding fire resistance and moderate mechanical properties.APD played fire resistant role in gas phase and condensed phase. [ABSTRACT FROM AUTHOR]

The thermal protection system (TPS) plays a major role in shielding solid rocket motors (SRMs) against structural failure from excessive heating. This study was directed at the recent innovation in flame‐retardant materials used for thermal insulation, with a particular focus on integrating metal–organic frameworks (MOFs) to bolster thermal stability. Three targeted transition metal‐BDC MOFs (MIL‐88(Fe), MOF‐71(Co), and MOF‐5(Zn)) were hydrothermally synthesized and the effect of incorporating these MOFs into nitrile butadiene rubber (NBR) composites was tracked. In general, the addition of the MOFs improved the interfacial compatibility and the processing of the composites. Additionally, experimental investigations have shown that all MOFs improved the mechanical properties of the NBR composite materials. Specifically, the addition of MOF‐5 has been found to increase the maximum tensile strength to 13 MPa, while MIL‐88 increased the elongation at break to 67.1%. In order to evaluate the thermal stability and ablative resistance of the prepared composites, the oxy‐acetylene flame test was utilized. Results showed that the efficiency of the composite as thermal insulation is highly dependent on the MOF type and the metal included. The impact of MOF‐71(Co) on thermal insulation displayed the least linear and mass ablation rates (0.0168 mm/s and 0.057 g/s, respectively) along with the lowest recorded back‐face temperatures, owing to the formation of a thick and compact char layer upon exposure to flames. [ABSTRACT FROM AUTHOR]

Inflammable building finishing materials act as a major cause of fire propagation, and they, therefore, pose significant risks to life and can lead to property damage. To replace such flammable building finishing materials, many countries have established regulations limiting their use, which has led to extensive research on the development of flame-retardant building finishing materials. Such methods have included adding flame retardants to construction materials to reduce the heat release rate and total heat release. The present study aimed to enhance the fire performance of cellulose-based architectural finishing materials by creating a dual flame-retardant mixture using expandable graphite and magnesium hydroxide added to recycled paper waste. Specimen fabrication involves using a pressing method to apply uniform pressure to compress the mixture in a mold. The total heat release (THR), CO, and CO2 production of the produced specimens were measured using a cone calorimeter while varying the magnesium hydroxide additive ratio. The combustion gases were measured through NES 713 experiments to determine any changes in the Toxic Index corresponding to variations in the magnesium hydroxide content. The experiment results established a correlation between the magnesium hydroxide additive ratio and the total heat release, as well as the existence of variations in CO and CO2 production for the dual flame-retardant recycled paper material. A database for combustion gases was also obtained. It was confirmed that the fire performance was improved by confirming that the total heat release decreased by 52% from the previous one in the magnesium hydroxide content of 30 g, and it was confirmed that the inflection points of the Toxic Index value due to the change in CO and CO2 gas production occurred in the magnesium hydroxide content of 20 g due to the improvement of the fire performance. Through the ISO 5660-1 experiment data, we have secured data that can be used as foundational information for performance-oriented fire risk assessments, thereby ensuring the fire safety of cellulose materials that are vulnerable to fire. [ABSTRACT FROM AUTHOR]

The flame-retardant performance of carbon fiber-reinforced composites is crucial for ensuring structural stability. Traditional additive flame-retardant methods often struggle to balance structural integrity with fire resistance. Herein, Ni(OH)2 and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were used as flame-retardant agents and mixed with glass fibers to construct the flame-retardant functional fiber veil which was used as the skin layer on the composite surface for fire protection. The structure performance and flame retardancy of composites were characterized via Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and a cone calorimeter test. The results confirmed that a flame-retardant glass fiber mat could effectively improve the flame-retardant and smoke-suppressive properties of the composite material. Due to the synergistic flame-retardant mechanism of Ni(OH)2 and DOPO, the C-N3-D2 composite with the highest LOI value of 32.3% has shown significant reduction in peak heat release rate (PHRR) and total smoke production (TSP) by 31.3% and 19.5%, respectively. In addition, due to flame-retardant agents only being employed in the skin layer of the composite, the core layer of a carbon fiber-reinforced structure could be protected without structure disruption. This approach maintained consistent interlayer shear strength, highlighting the effectiveness of using a flame-retardant fiber veil as a protective skin layer. This strategy could offer a viable solution for safeguarding high-performance composite materials from fire hazards without compromising their structural integrity. [ABSTRACT FROM AUTHOR]