Search

The flammability of rigid polyurethane foam (RPUF) limits its application. A new type of chitosan phase-change microcapsule (CS/PCM) was successfully prepared by the condensation method with chitosan and gum acacia as the wall material and paraffin as the core material. CS/PCM was introduced into RPUF composite material as filler to improve the thermal and flame-retardant properties of polyurethane. The morphology, structure, thermal properties and flame retardancy of the materials were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and cone calorimetry. It is found that when the CS/PCM content is 30 wt%, the latent heat of phase transition of RPUF-30 is 12.308 J/g, the limiting oxygen index (LOI) is 26.1% and the fire risk is reduced. The flame-retardant mechanism shows that the barrier effect provided by chitosan plays an important role in effectively blocking the transfer of heat and combustible gas, and improving the flame-retardant property of the composite. This paper provides a new idea for the application of CS/PCM in RPUF. [ABSTRACT FROM AUTHOR]

For many years, efforts have been made to reduce the flammability of unsaturated polyester resins (UPRs), which are often used in the rail, shipbuilding, and construction industries. Without modification, they often fail to meet fire safety standards. Despite a rich history of flame retardants (FRs) applied to UPRs, researchers seek new solutions that will provide lower flammability and smoke density, as well as attaining a lower environmental impact from the composites. The objective of the study is to highlight the most important recent research on promising nano FRs in order to promote their further development. Mechanisms of action of several groups of nano FRs, such as clay-based, carbon-based, transition metal compounds, layered double hydroxides, polyhedral oligomeric silsesquioxanes, and others, including bio-based, have been studied. Particular emphasis has been laid on nano FRs applied to UPRs, and their influences on thermal stability, flammability, and mechanical properties. Moreover, the environmental impact and toxicity of nano FRs have been discussed. Results have proved that nano FRs applied at low loadings may significantly improve thermal stability, with a simultaneous increase or only a slight decrease in mechanical properties. However, attention on related environmental issues has highlighted the necessity of carefully selecting novel nano FRs. [ABSTRACT FROM AUTHOR]

Limited by flammability, wood and wood-based materials face challenges in distinguishing themselves as structural materials or finishing materials. Once burning, they can produce toxic gases detrimental to humans and the environment. Therefore, it is critical to make clear whether fire-retardant wood construction materials are insusceptible to fire and not the sources of toxic gases. This study aimed to evaluate flame-retardant plywood from the aspects of flammability and the toxic gas and smoke generation during combustion. The flame-retardant plywood was manufactured by impregnating a flame-retardant resin in line with International Maritime Organization (IMO) standards. The research results indicate that seven out of the eight kinds of toxic gases listed by the IMO, other than CO, were not detected during the combustion of the flame-retardant plywood. While CO was detected, its quantities under three test conditions are below the corresponding thresholds. Therefore, unlike synthetic resin products, flame-retardant plywood is a promising finishing material that can reduce the damage from toxic gases in the event of a fire. In the smoke generation tests, the mass reduction rate of flame-retardant plywood increased from 13% to 18% and then to 20% as the test condition became more severe. Under the same circumstances, the average maximum specific optical density also followed an upward trend, whose values (75.70, 81.00, and 191.20), however, still met the IMO standard of below 200. This reflects that the flame-retardant plywood is competent as a finishing material. Further, flammability was evaluated, and the critical flux at extinguishment (CFE), total heat release (Qt), and peak heat release rate (Qp) were determined to be 49.5 kW/m2, 0.21 MJ, and 0.66 kW, respectively, which all did not reach the corresponding thresholds given by the IMO. To sum up, flame-retardant plywood has satisfactory flame-retardant performance and meets fire safety standards, showing the potential to be an attractive finishing material for building and construction. [ABSTRACT FROM AUTHOR]

Regarding environmental preservation, the upcycling of plastics from petroleum source is a consistent alternative. This work intended to investigate melting extruded composites of post-consumer HDPE (rHDPE) filled with pristine zirconium phosphate (ZrP), aluminum hydroxide [Al(OH)3] and aluminum hydroxide modifying-zirconium phosphate [ZrPOct/Al(OH)3]. Physico-mechanical and flame retardancy were assessed. FTIR revealed that rHDPE brought some degree of oxidative degradation probably from its cleaning process and/or processing. By nuclear magnetic resonance at time domain, rHDPE showed three relaxation domains. Fillers induced the lowering of rHDPE relaxation time owing to polymer/filler by hydrogen bonds. Diffraction pattern of rHDPE/Al(OH)3 and rHDPE/ZrPOct/Al(OH)3 indicated better fillers' dispersion. Fillers changed rHDPE crystallinity degree and thermal stability but rheologic properties were invariable. For all composites, elastic modulus increased (up to 17%) indicating stiffening. Yield strength did not change but stress and strain at break decreased. For the composites, SEM/EDS showed better dispersion and distribution of ZrP and ZrPOct/Al(OH)3 particles. It was assumed that ZrP and ZrPOct/Al(OH)3 greatly increased the flame retardancy. The work corroborates the importance of polymers' upcycling, and it is in consonance with the objectives of 2030 Agenda released by United Nations. [ABSTRACT FROM AUTHOR]

In this present investigation, a new attempt was made to produce sustainable polyester-based biocomposites using Lansium parasiticum fruit shell powder and hemp chopped fibre. The main objectives of this investigation were developing biocomposite and studying its mechanical, wear, water absorption and flammability properties. The powder was produced from waste fruit shell via ball milling process whereas the fibre was used in as-received form. The biocomposites are prepared using a hand layup method where post-curing is applied at 110 °C at the end of the process. The results revealed that the addition of fibre and filler improved the mechanical properties. A maximum tensile and flexural strength of 98 MPa and 143 MPa were noted for composite having 3 vol% filler and 40 vol% of fibre. Similarly, the addition of filler into the resin reduced the wear coefficient as well as wear loss. A lowest sp. wear rate of 0.009 mm3/Nm was recorded for composite made with 5 vol% of filler. But the water absorption and flammability were found to be affected marginally upon cellulosic fibre and filler addition. Nonetheless, they are in acceptable range indicating better hydrophobicity and low flammability. As a verdict, the combination of hemp fibre and Lansium parasiticum fruit shell powder along with polyester resin could be a noteworthy combination to form biocomposites with less cost, more eco-friendly and sustainable and circular economy concerns. Moreover, this practice could create a habit of producing sustainable eco-friendly products from waste, thus reducing the severity of solid waste accumulation. These new generation waste-derived biocomposites could be used as functional working material in applications starting from domestic to high performance engineering sectors. [ABSTRACT FROM AUTHOR]

Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, the poor weather resistance and aging resistance of additive flame retardants have caused researchers to pay attention to reactive flame retardants. A novel P‐N coacting epoxy curing agent with intrinsic flame retardancy was designed and synthesized. The mechanical properties, crosslinking curing properties and flame‐retardant properties of intrinsic flame‐retardant epoxy resin were characterized. The results show that the cross‐linking curing performance of hexa (3,5‐diamino‐1,2,4 triazolyl)‐cyclotriphosphonitrile) (VCP) is lower than that of DDM. This is due to the decrease in cross‐linking density caused by the VCP ring molecular structure. Therefore, the mechanical properties of the epoxy resin cured with VCP decreased, but the flame‐retardant properties of the material significantly improved. The limiting oxygen index of the VCP/EP flame retardant epoxy thermosets was 27.3%, reaching the UL 94 V‐1 level. The peak heat release rate and total heat release rate of the VCP/EP flame retardant epoxy thermosets were significantly reduced. The flame retardancy mechanism was studied by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and x‐ray photoelectron spectroscopy. The results show that the intrinsic flame‐retardant P‐N coacting epoxy resin has excellent curing and flame‐retardant properties. [ABSTRACT FROM AUTHOR]

A series of pentaerythritol derived flame retardant additives (FRs labeled FR1, FR2, FR3, and FR4) were synthesized and blended with thermoplastic polyurethane (TPU) to enhance its flame retardancy. The chemical structures of the FRs were established by FTIR, 1H, 13C and 31P NMR spectroscopy. The flammability of the TPU blends was analyzed through UL-94 vertical burning and limiting oxygen index (LOI) test. It is found that for FR4-TPU blends with 2% of phosphorus content, the LOI value reached up to 31.2%, and no melt dripping with a V-0 rating was obtained by UL-94, indicating its superior flame retardant properties. Thermogravimetric analysis (TGA) of TPU blends showed that the char yield increases from 3.9% in neat TPU to 20% with the addition of 2% of FR3 in TPU. Based on findings from scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), a possible mechanism for the flame retardant property of blends has been proposed. The improved flame retardant properties of TPU blends can be attributed to the formation of a continuous and highly entangled char. This work provides a suitable approach for synthesizing promising phosphorus-based flame retardants from readily available raw materials that can be used to enhance the flame retardancy of TPU. [ABSTRACT FROM AUTHOR]

In this work, we employed a two-step modification process to improve the properties of 2D bimetallic nanoplates M(OH)(OCH3) (M = Co, Ni), which were recently proven as a promising "nano-flame retardant". The nanoplates were in situ modified with metal-organic framework ZIF-67 first and then silanized with a coupling agent APTES. Epoxy resin (EP) nanocomposites were fabricated using the functionalized M(OH)(OCH3). We investigated the performance of the nanocomposites in flame retardance and thermal stability. The results showed that 3% of APTES@ZIF-67@M(OH)(OCH3) gave the EP nanocomposite the V-1 rating in UL-94 test and the highest limited oxygen index of 27.6%. Moreover, the pHRR value of EP/APTES@ZIF-67@M 3% was reduced by 20.0% and 9.6%, respectively, compared to neat EP and EP/ZIF-67@M 3%. Regarding the mechanical properties, the Tensile properties and energy storage modulus of EP nanocomposite were both improved with 3% of APTES@ZIF-67@M(OH)(OCH3). The GC-MS test results revealed that the functionalized M(OH)(OCH3) significantly increased the cross-linking propensity of the EP matrix upon combustion, leading to the formation of a dense char layer. This study demonstrates the great potential of M(OH)(OCH3) as a highly efficient "nano-flame retardant" with tunable functionality. [ABSTRACT FROM AUTHOR]

The paper describes the preparation of polyamide 6 with reduced flammability by anionic in situ polymerization of ε-caprolactam in the presence of flame retardants, a method not described in the literature. Selected inorganic and brominated organic flame retardants were characterized by thermogravimetric analysis. Polymerization tests were used to test the compatibility of flame retardants with the components of the initiation system of anionic polymerization. Based on their results, polyamide plates for the preparation of test specimens were prepared by the method of polymerization casting in a mold. The content of water-extractable portions did not exceed 3%, i.e., the conversion of monomer into polymer took place to a high degree. The presence of flame retardants both inorganic and brominated organic in the polymer matrix did not affect the thermal stability, the content of the crystalline phase and also the mechanical properties. Samples containing brominated organic flame retarders were classified as V-0 according to the UL94 methodology. [ABSTRACT FROM AUTHOR]

Purpose: It is an indispensable part of airworthiness certification to evaluate the fuel tank flammability exposure time for transport aircraft. There are many factors and complex coupling relationships affecting the fuel tank flammability exposure time. The current work not only lacks a comprehensive analysis of these factors but also lacks the significance of each factor, the interaction relationship and the prediction method of flammability exposure time. The lack of research in these aspects seriously restricts the smooth development of the airworthiness forensics work of domestic large aircraft. This paper aims to clarify the internal relationship between user input parameters and predict the flammability exposure time of fuel tanks for transport aircraft. Design/methodology/approach: Based on the requirements of airworthiness certification for large aircraft, an in-depth analysis of the Monte Carlo flammability evaluation source procedures specified in China Civil Aviation Regulation/FAR25 airworthiness regulations was made, the internal relationship between factors affecting the fuel tank flammability exposure time was clarified and the significant effects and interactions of input parameters in the Monte Carlo evaluation model were studied using the response surface method. And the BP artificial neural network training samples with high significance factors were used to establish the prediction model of flammability exposure time. Findings: The input parameters in the Monte Carlo program directly or indirectly affect the fuel tank flammability exposure time by means of the influence on the flammability limit or fuel temperature. Among the factors affecting flammability exposure time, the cruising Mach number, balance temperature difference and maximum range are the most significant, and they are all positively correlated with flammability exposure time. Although there are interactions among all factors, the degree of influence on flammability exposure time is not the same. The interaction between maximum range and equilibrium temperature difference is more significant than other factors. The prediction model of flammability exposure time based on multifactor interaction and BP neural network has good accuracy and can be applied to the prediction of fuel tank flammability exposure time. Originality/value: The flammability exposure time prediction model was established based on multifactor interaction and BP neural network. The limited test results were combined with intelligent algorithm to achieve rapid prediction, which saved the test cost and time. [ABSTRACT FROM AUTHOR]

In this research, a series of silicone foam/polytitanosiloxane composites (SF-pTS) were fabricated with hydroxy-, vinyl-, hydrogen-containing polydimethylsiloxanes, and polytitanosiloxane filler in the presence of a platinum catalyst under ambient conditions. The effect of the amount of polytitasiloxane on the micromorphology and flame retardancy of silicone foam was studied, and a relative flame retardancy mechanism was proposed. It could be found that the polytitanosiloxane exhibited a good dispersion level in the silicone foam, thus improving the flame retardancy of the composite. When the content of polytitanosiloxane is 9 wt%, the limiting oxygen index and UL-94 grade of the SF-pTS9 composite are increased to 29.2% and FV-0, respectively. Cone experiment results suggested that the SF-pTS9 possessed relative balanced PHRR (148.9 kW/m2), THR (58.5 MJ/m2), TSP (0.6 m2), and mass residue (83.9%) among the prepared silicone foam materials. This work provides a new avenue to fabricate a silicone foam composite with enhanced flame retardancy. [ABSTRACT FROM AUTHOR]

Water-blown biopolyurethane (bioPUR) foams are flammable and emit toxic gases during combustion. Herein, a novel approach suggested by the current study is to use different amounts of lignin waste (LigW), which increases the thermal stability and delays the flame spread and sodium silicate (LG), which has foaming ability at high temperatures and acts as a protective layer during a fire. However, there have been no studies carried out to investigate the synergy between these two materials. Therefore, two different ratios, namely 1/1 and 1/2 of LigW/LG, were used to prepare bioPUR foam composites. The obtained bioPUR foam composites with a 1/2 ratio of LigW/LG exhibited inhibition of flame propagation during the ignitability test by 7 s, increased thermal stability at higher temperatures by 40 °C, reduced total smoke production by 17%, reduced carbon monoxide release by 22%, and increased compressive strength by a maximum of 123% and 36% and tensile strength by a maximum of 49% and 30% at 100 °C and 200 °C, respectively, compared to bioPUR foam composites with unmodified LigW. Additionally, thanks to the sufficient compatibility between the polymeric matrix and LigW/LG particles, bioPUR foam composites were characterised by unchanged or even improved physical and mechanical properties, as well as increased glass transition temperature by 16% compared to bioPUR foam composites with unmodified LigW particles, making them suitable for application as a thermal insulating layer in building envelopes. [ABSTRACT FROM AUTHOR]

Fibre-reinforced composites laminates (FRCLs) are employed in various applications such as in marine, aerospace, automotive, and civil industries due to their lightweight nature, design tailorability, and superior specific mechanical properties. However, they possess extremely low flame resistance mainly due to the inherent flammability of the polymer matrix. Various treatments have been applied to improve the fire resistance of FRCLs. In particular, hybridisation (fibre hybridisation and polymer hybridisation) is an important technique which is becoming very popular to enhance the thermal performance and flame resistance of FRCLs. This article is a comprehensive review of the recent developments that broadly cover the improvements in fire resistance of composite laminates via multi-scale hybridisation; the characteristics of thermal decomposition of FRCLs have been presented to comprehend the need for flame retardancy. Approaches for improving the fire resistance of FRCLs and thermal stability, both in polymer and in fibre systems, are discussed. Enhancing the fire resistance has been significant through additives to the matrix, use of flame-retardant modified fibres at interfacial regions and by way of multi-layered hybrid laminates besides hybridization at fibre, yarn and layer level. Finally, a review is presented on the modelling of fire resistance of composite laminates by considering thermo-mechanical models for the prediction of decomposition and failure of laminates at elevated temperatures. [ABSTRACT FROM AUTHOR]

Due to the increasing demand for low carbon fuels, ammonia is considered a viable option. Considering the problems associated with the combustion of ammonia, such as its narrow flammability range, it has been suggested to use it together with other fuels, such as methane. Following previous studies, which mainly focus on the emission of this fuel mixture in burners and simplified chambers, this research attempts to conduct an experimental and numerical study with a greater emphasis on performance parameters and pollution in an actual microturbine combustion chamber. The study investigates the effect of a mixture of ammonia with methane and its fraction on the combustion performance of the combustor and its emissions (NOx, CO) in two different thermal powers. The results showed that flame temperature decreased as the fraction of ammonia in the fuel increased, and the flame moves away from the injector. It also appeared that adding ammonia to the fuel increased the amount of NOx produced in the combustor without reducing CO significantly. Also, the combustor outlet temperature remained almost unchanged, but the combustion efficiency of the combustor decreased as the ammonia fraction increased. • Investigated performance and emissions of microturbine combustor with ammonia/methane fuel mixture. • Stable combustion achieved up to 50% mixing ratio, without altering combustor configuration. • Lowering reaction rate delays ignition and hampers chamber performance. • Ammonia in methane reaction reduces complete combustion, causing elevated CO and NOx emissions. • Higher ammonia ratio reduces combustor efficiency, raises pattern factor, with constant output temperature. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) is a versatile polymer with numerous applications that has undergone substantial changes in recent years, focusing on the demand for next-generation polymers. This article provides a comprehensive review of recent research in PP and its advanced functional applications. The chronological development and fundamentals of PP are mentioned. Notably, the incorporation of nanomaterial like graphene, MXene, nano-clay, borophane, silver nanoparticles, etc., with PP for advanced applications has been tabulated with their key features and challenges. The article also conducts a detailed analysis of advancements and research gaps within three key forms of PP: fiber, membrane, and matrix. The versatile applications of PP across sectors like biomedical, automotive, aerospace, and air/water filtration are highlighted. However, challenges such as limited UV resistance, bonding issues, and flammability are noted. The study emphasizes the promising potential of PP while addressing unresolved concerns, with the goal of guiding future research and promoting innovation in polymer applications. [ABSTRACT FROM AUTHOR]

The effect of expanded vermiculite (e-VMT) was evaluated relative to the physical, mechanical, and flame retardancy performance of flat-pressed wood plastic composites (WPCs). Various contents of e-VMT (2.5, 5, 7.5, 10, 15%) were added instead of wood flour (WF) to the matrix. Due to the hydrophilic nature of the WF, water absorption (WA) and thickness swelling (TS) of WPCs increased as compared to neat polymer-based panels. Meanwhile, e-VMT incorporation limited the WA and TS values. As expected, the lowest WA and TS values were obtained from the highest e-VMT-reinforced WPCs. The addition of e-VMT was also found to enhance the mechanical properties of WPCs. As the e-VMT content increased and the WF content decreased, there was an improvement in flexural strength, modulus of elasticity (MOE), and tensile strength. Compared to the neat polymer panels, the MOE of WPCs increased by up to 77%. Additionally, the flame retardancy performance of WPCs improved with e-VMT reinforcement, with limiting oxygen index (LOI) values increasing up to 24%. Scanning electron microscopy (SEM) images also demonstrated the favorable integration of e-VMT with matrix, thereby improving the mechanical properties. The inconsistency between WF and polymer was also well-observed, highlighting the tendency of WF to interact easily with water. [ABSTRACT FROM AUTHOR]

Incorporating nano-sized fillers into bio-based polyurethane (PU) foams typically enhances their properties. In present investigation, palm oil-based PU foams are fabricated with varied loadings (0 to 5 wt%) of fumed nanosilica. The foams are then characterized for their fire-retardancy, thermal stability, foam morphology, and also mechanical properties. Marginal improvement in Limiting Oxygen Index (LOI) values, as well as failure to be rated under UL-94 Vertical Combustion Test indicate limited potential of fumed silica in improving flammability of organic polymeric foams; suggesting exorbitant amount is required for any distinguishable effect to manifest. Interestingly; results from Thermogravimetry Analysis (TGA) shows marked improvements in terms of char residue with more than seven-fold increase at 5 wt% filler loading, possibly owed to the inert filler nature of fumed nanosilica forming a char barrier and acting as fuel diluent. Filled PU foams displayed an increased open-cell content, likely because the filler functioned as a cell opener. Removing the influence of density, the normalized compressive properties showed notable improvement up until a certain loading, which could be credited to the increased stiffness imparted by the filler itself. The results portray the potential of fumed nanosilica as filler for bio-based PU foams, offering enhanced thermal stability and limited fire retardancy. [ABSTRACT FROM AUTHOR]

The presence of massive amounts of toxic volatiles and smoke during combustion is a very serious problem facing epoxy resin (EP) composites. Therefore, flame retardants (FRs) can simultaneously enhance flame retardancy and reduce the release of smoke and fatal gases. Herein, a novel sulfur–phosphorous reactive flame retardant (SPMS) was synthesized for epoxy resin. The high efficiency of smoke suppression and flame retardancy of the EP/SPMS-APP hybrid was investigated using a cone calorimeter, a vertical burning test, and limited oxygen index measurements. Compared with those of pure EP, the composite with 20 wt% SPMS-APP reduced the peak heat release rate (pHRR), the peak smoke production rate (SPR), and total smoke production rate (TSR) by 82%, 94%, and 84%, respectively. The results showed a remarkable suppressed effect of alleviating the fire hazard of EP using a sulfur–phosphorus flame retardant. [ABSTRACT FROM AUTHOR]

Flax fabric textile is of great interest as bio‐fiber reinforcement in composites, which has gained popularity due to the high demand for sustainable materials. Despite its sustainability, flax is inherently flammable. This study demonstrates a two‐step polyelectrolyte complex (PEC) coating that renders flax fabric self‐extinguishing. The PEC coating consists of polyethylenimine (PEI) and sodium hexametaphosphate (PSP), cured with a citric acid buffer. Sonication employed during the curing process improves the infiltration of the coating into the flax fibers and maintains the fabric's hand. When comparing non‐sonicated and sonicated flax samples, the latter achieves self‐extinguishing behavior and passes the vertical flame test. Pyrolysis‐combustion flow calorimetry reveals that this PEI/PSP coating (with sonication) reduces the peak heat release rate and total heat release by 40% and 67%, respectively. The intumescent mechanism is predominantly observed in the condensed phase, as suggested by differential scanning calorimetry and X‐ray photoelectron spectroscopy. The results demonstrate that the two‐step PEC treatment with sonication effectively reduces the flammability of flax fabric, making it a promising option for the development of functional fibers, particularly for bio‐composite reinforcement. [ABSTRACT FROM AUTHOR]

In this study, a DOPO-based reactive flame retardant (DRFR) was synthesized and used as the second diphenol structure for preparation of flame-retardant rigid polyurethane foam (FR-RPUF). DRFR, as a phosphorus/nitrogen-containing diphenol, was prepared from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 4-hydroxy benzaldehyde, and benzidine. FR-RPUF was synthesized from polyether polyol (DaltoFoam TA® 14066) as the first hydroxyl-rich structure, DRFR as the second diphenol, and 4,4′-diphenylmethane diisocyanate through the one-pot method. For comparison, a pure rigid polyurethane foam (pure RPUF) was also synthesized without DRFR. The thermal stability of pure RPUF and FR-RPUFs was investigated by using thermogravimetric analysis (TGA). According to thermogravimetric analysis results, the temperature at 5 mass% loss (T5%) increased from 222 to 238 °C for sample containing 2 mass% of DRFR. Also, the char residue at 700 °C was enhanced by introducing DRFR. Flame retardancy and burning behavior were determined by the limiting oxygen index (LOI) and vertical burning test (UL-94). The LOI value of FR-RPUF sample containing 3 mass% DRFR achieved 21.5%, and the UL-94 test improved from no rating for pure RPUF to V-1 rating for FR-RPUFs. Compared with the pure RPUF, the resultant FR-RPUFs indicated better fire resistance and thermal stability. The dynamical mechanical thermal analysis results revealed that the storage modulus for FR-RPUFs is higher than pure RPUF, which attributed to the good interaction between DRFR and PU matrix. [ABSTRACT FROM AUTHOR]

Hybrid graphene filled glass/sisal fiber-reinforced epoxy nanocomposites were successfully synthesized with different weight percentages (0%, 0.25%, 0.5%, 0.75% and 1%) of graphene nanoplatelets. The objective of this study was to investigate the effect of weight fraction of graphene on the mechanical and physical properties of the hybrid glass/sisal fiber-reinforced epoxy nanocomposites such as tensile, flexural, hardness, density, void content, flammability, water absorption and thickness swelling. The hybrid nanocomposites were fabricated using the vacuum bag-assisted hand lay-up technique. Different layup sequences were achieved by changing the position of the glass/sisal fiber layers, maintaining a total of five layers in each composite. The obtained results suggested that the addition of 1% graphene nano filler into the sisal/glass hybrid composite enhanced the tensile strength by 49.7% and Young's modulus by 60%. Among GNP reinforced hybrid composites, highest value of toughness (16 J) was found in case of the composite containing 1 wt.% GNP. However, when 0.5% of GNPs were added in the composite, the flexural strength and modulus reached a maximum of 306 MPa and 25 GPa, respectively, which are 228% and 362% greater than sisal/glass hybrid composites. The water absorption of the composite sample containing 0.5% GNPs was 4.62% lower than those of other hybrid glass/sisal fiber reinforced epoxy composite. Furthermore, addition of 0.5 wt% GNP resulted in a decrease in the burning rate of the hybrid composite from 11.22 mm/min to 7.6 mm/min and from 23.13 mm/min to 20.18 mm/min, respectively. [ABSTRACT FROM AUTHOR]

Wood-based functional materials have developed rapidly. But the flammability significantly limits its further application. To improve the flame retardancy, the balsa wood was delignified by NaClO2 solution to create a cellulose scaffold, and then alternately immersed in CaCl2 ethanol solution and NaHCO3 aqueous solution under vacuum. The high porosity and wettability resulting from delignification benefited the following mineralization process, changing the thermal properties of balsa wood significantly. The organic-inorganic wood composite showed abundant CaCO3 spherical particles under scanning electron microscopy. The peak of the heat release rate of delignified balsa-CaCO3 was reduced by 33% compared to the native balsa, according to the cone calorimetric characterization. The flame test demonstrated that the mineralized wood was flame retardant and selfextinguish. Additionally, the mineralized wood also displayed lower thermal conductivity. This study developed a feasible way to fabricate a lightweight, fire-retardant, self-extinguishing, and heat-insulating wood composite, providing a promising route for the valuable application of cellulosic biomass. [ABSTRACT FROM AUTHOR]

Rigid polyurethane foam (RPUF) has been prepared at various amounts of aluminium hydroxide (ATH) flame retardants (10,20,30,40,50 wt. %). This study aims to examine the thermal, and fire behaviour of RPUF by exploring the ATH as a flame retardant. The effect of different contents of ATH constituents on RPUF was investigated. Results from thermogravimetric analysis TGA showed that the thermal stabilities of composite foam were higher than that of pure RPUF. The results of the limiting oxygen index test showed that 50 wt. % aluminium hydroxide (ATH) enhanced the limiting oxygen index (LOI) value of the composite by 23 % compared to pure RPUF. All aluminium hydroxide (ATH) contents were observed to have contributed to the boosted flame retardancy of RPUF. The RPUF composite showed great potential for being employed as insulation material. [ABSTRACT FROM AUTHOR]

In this study, numerical methods were used to assess the effects of adding hydrogen and varying the equivalence ratios on the combustion and emission properties of a non-premixed combustor. The results revealed that the additions of H 2 and varying Φs significantly affected the flame configuration and emission characteristics. An elevation in the H 2 vol. Promotes fuel combustion, yielding a higher flame temperature and a wider flammability region. Lower Φs and increased H 2 vol. Significantly decrease CO and CO 2 emissions by 87.48% and 96.63% respectively. Conversely, NOx emissions increase with higher H 2 vol. and Φs due to the catalytic effect of elevated flame temperature. At Φ = 0.2 and 50 vol% of H 2 , outlet temperature and pattern factor were enhanced by 61.66% and 30.16% respectively. Under these conditions, NOx emission was calculated by a factor of 74.14. Investigation emphasizes hydrogen-enriched fuels' potential for enhancing combustion and emissions control through vol. and equivalence ratios. • Hydrogen-enriched fuel mixture combustion is realized in a can-type combustor. • Effects of H 2 enrichment and equivalence ratios on combustion are investigated. • The addition of H 2 in the fuel mixture enhances combustion performance. • CO, CO 2 , and NO x pollutant emissions are numerically computed. [ABSTRACT FROM AUTHOR]

[Objective]To study the burning characteristics of litters from different common forest types in west Sichuan can help assess the risk and intensity of surface fires in different forest types.[Method]Six common forest types in the western Sichuan region were selected and their litter moisture content, ash content, ignition point, dry weight calorific value（GCV）,and ash free calorific value（AFCV） were measured.By using principal component analysis, the variation in burning characteristics across different forests were comprehensively evaluated.[Result]The results showed that the differences in moisture content, ignition point, gross calorific value（GCV）,and ash-free calorific value（AFCV） were significant among different forest types.Through comprehensive analysis, the flammability of litters from six common forest types in western Sichuan was ranked as follows: Pinus radiata ＞ Pinus densata ＞ Pinus armandii ＞ Quercus semicarpifolia ＞ Pinus yunnanensis＞Picea asperata-Abies fabri. [Conclusion]In this study, we measured and analyzed the burning characteristics of litters from six common forest types in western Sichuan.Our study can help predict the risk and intensity of surface fires in different forest types, and provide references for fire prevention. [ABSTRACT FROM AUTHOR]

Transparency is an important property for polymer flame retardants, especially epoxy resin (EP) flame retardants, and flame-retardant epoxy resins that maintain a high transparency and low chromatic aberration play important roles in the optical, lighting, and energy industries. Herein, a DOPO-based flame retardant 6,6′-((sulfonylbis(4,1-phenylene))bis(oxy))bis(dibenzo[c,e][1,2]oxaphosphinine 6-oxide) with a high transparency and low chromatic aberration was prepared via the classical Atherton–Todd reaction and named SBPDOPO. Its chemical structure was characterized with Fourier IR spectroscopy and NMR spectroscopy. An EP loaded with 7 wt% SBPDOPO passed the UL-94 V-0 rating with an LOI value of 32.1%, and the peak heat release rate, total heat release, and total smoke production were reduced by 34.1%, 31.6%, and 27.7%, respectively, compared with those of pure EP. In addition, the addition of SBPDOPO improved the thermal stability, residual mass, and glass transition temperature of the EP. On this basis, the EP containing 7 wt% SBPDOPO maintained a high transparency and low color aberration, with a transmittance of 94% relative to that of pure EP and a color aberration ΔE of 1.63. Finally, the flame-retardant mechanism of SBPDOPO was analyzed, which demonstrated that it exerted both gas-phase and condensed-phase flame-retardant effects, and that SBPDOPO/EP had high potential for application scenarios in which both flame retardancy and transparency are needed. SBPDOPO/EP has great potential for applications requiring both flame retardancy and transparency. [ABSTRACT FROM AUTHOR]

• The flammability limits of R134a/R1270, R134a/R170 and R170/R1270 were measured. • R134a demonstrates a significant flame-retardant effect at volume ratios above 0.75. • The flame color and propagation speed of refrigerants were compared and analyzed. Hydrocarbons (HCs) are considered promising alternative refrigerants due to their excellent thermodynamics, transport properties, and environmental friendliness. However, hydrocarbons are flammable. Conversely, R134a is a widely used non-flammable refrigerant but was listed in the Montreal Protocol-Kigali Amendment due to its relatively high global warming potential (GWP). Therefore, in order to reduce the GWP of R134a and inhibit the flammability of hydrocarbon refrigerants, this study investigated the flammability characteristics of mixed refrigerants R134a/R1270, R134a/R170, and R170/R1270. The flammability limits of different concentrations of R170/R1270, R134a/R1270, and R134a/R170 were measured under standard conditions, and the inhibition mechanism of R134a was briefly analyzed. Additionally, the flammability limits of R170/R1270, R134a/R1270, and R134a/R170 were predicted using the polynomial fitting method. Subsequently, the flame propagation speed and the flame color of R1270 and R170, with and without R134a, were compared and analyzed. Furthermore, the cycle performance of R134a/HCs was calculated. The research results are expected to provide guidance for the safe and effective utilization of R1270, R170, and their mixtures in refrigeration systems. [ABSTRACT FROM AUTHOR]

This work aims to improve the thermal stability and flame retardancy of cotton fabrics treated just by a single SiO2, a single B2O3 and their binary composite sol–gel systems. Tetraethyl orthosilicate (TEOS) and tributyl borate were used as precursors. The sols were coated onto cotton fabrics via dipping-baking processes. Techniques including Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), limiting oxygen index (LOI) and vertical burning test (VBT) were used to investigate the surface functional groups, elemental compositions, crystal structures, surface morphologies, elemental contents, thermal stability and flame retardancy levels of original and sols-treated cotton fabrics, respectively. The results show that the sols converted gel coatings are successfully deposited on the cotton fabric surfaces. SiO2-B2O3 sol finishing cotton fabric shows the best flame retardancy. It shows the highest char residue rate (43.82%), the highest LOI (25.7%) and ΔLOI/Δm (7.0%/g), the lowest after-flame time (10.0 s) and after-glow time (0.0 s without a smoldering process), a relatively complete and continuous char residue after a VBT. The SiO2 and B2O3 sol–gel systems play more synergistic effects than competitive effects in flame retarding a cotton fabric. A SiO2 gel shows effects of a high melting point, a structural support and dimensional stability, while a B2O3 gel shows a fusing capability and a longer pyrolysis process. [ABSTRACT FROM AUTHOR]

Biomass aerogels have attracted wide attention due to their excellent thermal insulation properties, but their low mechanical strength and high susceptibility to combustion limit their application. To address these limitations, a novel composite aerogel was prepared by combining chitosan aerogel (CS) and hydroxyapatite nanowires (HAP) via phytic acid (PA) cross‐linking and freeze‐drying. It was found that the maximum compressive strength and modulus of CS/HAP aerogel were 1.13 and 0.67 MPa, respectively. The minimum thermal conductivity of CS/HAP(0.5) composite aerogel was 0.03921 W m−1 K−1, indicating its good thermal insulating property. Moreover, the CS/HAP composite aerogel also showed excellent flame‐retardant properties. The heat release rate (HRR) and total heat release from combustion (THR) were significantly lower than those of the CS aerogel, with values of 35.2 kW m−2 and 3.7 MJ m−2, respectively, compared to 169.6 kW m−2 and 5.4 MJ m−2. The total smoke release (TSR) was also at a low level, reaches 0.4 m2 m−2. Highlights: Propose a novel chitosan aerogel composited with inorganic nano‐reinforced HAP.High mechanical strength of CS/HAP composite aerogel are illustrated.Exhibit excellent thermal insulation performance of CS/HAP aerogel.HAP and PA largely improves the flame retardancy of the chitosan aerogel. [ABSTRACT FROM AUTHOR]

A novel phosphorus‐based maleimide, tris[4‐(2,5‐dioxopyrrol‐1‐yl)phenyl] phosphite (TDPPI), was employed as a flame retardant in epoxy with moderate transparency, enhanced thermal stability, and improved mechanical strength. SEM studies ascertained the uniform dispersion of TDPPI and its compatibility with the epoxy. Differential scanning calorimetry showed that the epoxy compounded with 2.5 wt% of TDPPI achieved 100% curing with the glass transition temperature of 43.8°C. The thermogravimetric study revealed that the presence of 2.5 wt% of TDPPI in epoxy increased the residual mass found at 600°C by 23%. The epoxy thermoset compounded with 2.5 wt% of TDPPI passed the Underwriter's Laboratory (UL‐94) test with V‐1 classification and achieved the limiting oxygen index of 30.7% with a reduced burning rate of about 58.7%. At 1.5 wt% of the TDPPI, the resulting epoxy thermoset exhibited an enhancement in the tensile strength (23%), Young's modulus (37%), flexural strength (9%), and Izod impact strength (37%) relative to the neat epoxy. In conclusion, 2.5 wt% of TDPPI is adequate for imparting flame retardancy to epoxy composites with improved mechanical strength because of the maleimide‐phosphorus synergistic effect. Highlights: TDPPI is a phosphorus and maleimide containing flame retardant.TDPPI improves thermal stability, flame retardancy and mechanical strengths.Only 2.5 wt% of TDPPI is required for epoxy to achieve high flame retardancy.Maleimide presence lowers phosphorus requirement for epoxy flame retardancy.TDPPI is a promising new flame retardant material for epoxy. [ABSTRACT FROM AUTHOR]

A feature of Chinese historical buildings is the preservation of many traditional customs, such as using candles and incense burners, and decorating the rooms with some textiles. Therefore, there are both many fire sources and combustible materials indoors, which puts a huge threat to fire safety. Although some researchers have experimentally studied the ignition and fire spread characteristics of several combustible materials, to better conduct fire risk assessment in historical buildings, the dynamic burning behavior of common fuels should be further analyzed. This paper carried out experimental investigations for flammability and fire spread behaviors of combustible materials usually used in Chinese historical buildings, which are made of both natural fiber and synthetics. Considering practical applications, the size of each sample is chosen from standard-testing size to real size. It is summarized that there are large deviations among different materials due to their ingredients, textures, structures, etc. The natural-based materials are easy to be ignited and burn up quickly, and some synthetics reveal sharp increase in heat release rate. For the synthetics, as it can melt during burning, the flame spread process is accompanied by dripping. Once there are some combustibles near it, the dripping part is liable to ignite the combustibles and cause damage to cultural relics. Based on these knowledges, fire hazards of different materials in Chinese historical buildings are evaluated. [ABSTRACT FROM AUTHOR]

In boreal forests fires often ignite and spread within the dominant moss and lichen cover of the ground layer vegetation, which thus greatly influences fire hazard. We used an experimental set-up in greenhouse conditions to study the differences in how (1) fuel moisture and (2) wind velocity influence the ignition probability and fuel consumption among four common circumboreal ground vegetation fuels, Pleurozium schreberi (Willd. ex Brid.) Mitt., Hylocomium splendens Schimp., Dicranum spp. and Cladonia rangiferina (L.) F. H. Wigg. Our results show that the reindeer lichen C. rangiferina was clearly the most flammable species, with high ignition probability even at high moisture contents and low wind velocities. Of the mosses, Dicranum was the least flammable, with low ignition probability and mass loss at low wind velocities regardless of moisture content. P. schreberi and H. splendens behaved somewhat similarly with wind velocities quickly increasing the initially low ignition probability and mass loss observed in the absence of wind. However, especially for mass loss, among-species differences tended to disappear with stronger winds. The observed differences can be explained by the different structures and growth forms of the studied species and open a potential avenue for improving forest fire risk predictions.

Anaerobic Digestion (AD) of mono-substrate is reported to be ineffective due to nutritional imbalance and lack of a variety of microbes. Anaerobic co-digestion of substrates is the advised alternative to mono-digestion to boost the generation of quality biogas. Brewers’ Spent Grains (BSG) contain high organic matter content and can be used in the production of biogas towards reducing the reliance on fossil fuel-based energy sources. Biogas generation from BSG can be improved through the co-digestion process via the inclusion of extra substrate. The current study explored the quality of biogas generated through co-digestion of BSG and cattle dung (CD). Digestion of two substrates was managed at a retention time of 10 days at BSG: CD ratios: 1:3, 1:2, 1:1, 2:1, 3:1, BSG and CD control experiments with substrates combination of 4.5 kg in each setup. Plastic bottles (10 L) were used as bio-digesters with substrates and water at a 1:1 ratio to allow anaerobic digestion (AD) to proceed. Results showed that BSG: CD ratios of 1:3 and 1: 2 with total solids (TS) content of 9.24% and 8.95% produced the highest quality raw biogas rich in methane. Both ratios 1:3 and 1:2 produced Methane which exhibited a 100% lower explosive limit (LEL) at an average of 40.3 ± 29.88 % LEL d−1 and 40.28 ± 33.39 LEL d−1 respectively; with a respective methane content of 54.7 ± 10.74% CH4d−1 and 51.9 ± 8.67% CH4d−1. The current study provides a facile and convenient optimal ratio between BSG and CD for the production of high-quality biogas using environmentally prevalent materials.

Purposes At present, the contradiction between energy supply and demand is increasingly intensifying, and high-temperature heat pumps, as an energy-saving and emission-reduction technology, can upgrade a large amount of low-grade waste heat to high-grade energy for utilization. Methods Five environmentally friendly heat pump working fluids are proposed, R1233zd(E)/R1234ze(Z)(0.15:0.85), R600a/R1233zd(E)(0.70:0.30), R600a/R1233zd(E)/R600(0.01:0.15:0.84), R600a/R1233zd(E)/ethylene oxide (0.34:0.01:0.65), and R1233zd(E)/R1234ze(Z)/R245ca/R600a (0.39:0.58:0.01:0.02). The performance of the new working fluid and the existing working fluid R245fa is compared in terms of basic thermophsical properties, cycle performance, and safety. Findings The results show that the five alternative working fluids proposed are superior to R245fa in terms of viscosity, constant pressure specific heat, thermal conductivity, and condensation heat, and have outstanding environmental performance. For the cycle performance, under the condition of condensing temperature of 110 ℃, the alternative working fluid COP is close to R245fa, and the unit volume of heat production is 111%, 144%, 125%, 144%, and 108% of R245fa, respectively. The group contribution method is used to predict the flammability of the new working fluid, and the results show that R1233zd(E)/R1234ze(Z)(0.15:0.85), R600a/R1233zd(E)(0.70:0.30), and R1233zd(E)/R1234ze(E)/R245ca/R600a (0.39:0.58:0.01:0.02) are estimated to be non-flammable mixtures. Conclusions All the five working fluids have the potential to replace R245fa, and R1233zd(E)/R1234ze(Z) (0.15:0.85) is the most recommended, which has good comprehensive performance.

In this work, studies were performed on oxidative stability by determining the transmittance spectra, the components and trichomatic coordinates, and the color differences for grape seed oils (GSO) subjected to a forced oxidation treatment at temperatures of 100 °C and 120 °C, for 4, 8 and 10 h. For this purpose, a constant airflow of 30 L/min was used. GSO was also subjected to flammability tests on a heated cylindrical surface to determine the lowest temperature at which this oil ignites, correlated with the highest temperature at which the oil does not ignite. According to the results, these temperatures are 475 °C and 470 °C, respectively. At these temperatures, the tested oils were darker in color than the reference oil, with the L* parameter having lower values (91.53 and 89.56, respectively). In addition, the correlation coefficients between the evaluated parameters were significant (p ≤ 0.05).

The goal of this work was to develop acrylonitrile–butadiene (NBR) elastomer composites filled with hydroxyapatite (HAP) characterized by improved cure characteristics and resistance to burning. Silane, i.e., (3-aminopropyl)-triethoxysilane, ionic liquid, i.e., 1-decyl-3-methylimidazolium bromide and surfactant, i.e., cetyltrimethylammonium bromide, were used to improve the filler’s dispersibility in the elastomer matrix and to reduce the time and temperature of vulcanization. The effects of HAP and dispersants on the cure characteristics, crosslink density and physico–chemical properties of NBR composites were explored. The additives used, especially the ionic liquid and surfactant, effectively improved the dispersion of HAP in the NBR matrix. The amount of HAP and the dispersant used strongly affected the cure characteristics and crosslink density of NBR. The optimal vulcanization time significantly increased with HAP content and was pronouncedly reduced when ionic liquid and surfactant were applied. In addition, ionic liquid and surfactant significantly lowered the onset vulcanization temperature and improved the crosslink density and hardness of the vulcanizates while impairing their elasticity. HAP and dispersants did not significantly affect the damping properties or chemical resistance of NBR vulcanizates. Above all, application of HAP considerably enhanced the resistance of vulcanizates to thermo-oxidative aging and reduced their flammability compared with the unfilled NBR.

The South Korean government has implemented an acceptance system to promote the high-quality recycling of waste. Industrial waste generators must provide “hazardous characteristics data” to recycling operators. Nonetheless, ~80% of industrial safety accidents in South Korea occur during recycling, most involving fire or explosions. Moreover, a gap in safety management exists during ‘Circular Resource’ acceptance if the target substance is not regarded as waste. In this study collected data on hazardous waste characteristics. From 62 waste generators, 72 waste samples were collected, accounting for most of the resources accepted for recycling, including waste synthetic polymers, slag, dust, waste sand, and waste foundry sand. Then, the hazardous characteristics, as stated in the Ministry of Environment notifications, were assessed. Leaching toxicity was detected in one slag sample and six dust samples. The Cd, Cu, As, Pb, Zn, Ni, Hg, F, and CN levels dissatisfied the Soil Contamination Warning Standard in 31 samples. Explosivity was not detected in any sample, whereas flammability was detected in one waste synthetic polymer sample. The results revealed 15 cases of potential flammability. Flammability is legally defined as below the criteria if the combustion speed criterion is not met. However, in the case of flame ignition, which could cause large fires and safety accidents, the relevant notification should be revised. In this study, we aimed to improve the gap between the hazardous waste management systems and industrial fields through actual measurements of hazardous characteristics. By doing so, we seek to contribute to the prevention of environmental and safety accidents. By continuously accumulating data and utilizing actual measurements, we aim to revise and enhance relevant regulations, ultimately improving the hazardous characteristics of waste management systems.

This paper aimed to provide technical support for fuel management by exploring different strengths of fuel removal on the physical and chemical properties and flammability of Betula platyphylla forests in the wildland–urban interface. After investigating the northeastern region during the forest fire prevention period in May 2023, a typical WUI area was selected, and three different treatment strengths, combined with a control, were set up to carry out indoor and outdoor experiments for 27 weeks. Compared with previous studies, this study mainly investigated and analyzed the dynamic changes in the physical and chemical properties and fuel flammability after different intensities of treatments on a time scale. By processing and analyzing the data, the following results were obtained. Significant differences existed in the fuel loading of different time-lag fuels over time (p < 0.05). The ash and ignition point of 1 h time-lag fuel after different treatment intensities generally increased first and then decreased, and the higher heat value and ash-free calorific value generally decreased first and then increased. The physical and chemical properties of 10 h and 100 h time-lag fuel fluctuated with time, but the overall change was insignificant. The indicator that had the greatest impact on the combustion comprehensive score for different time-lag fuels was fuel loading. The change in the flammability of dead surface fuel with time varied significantly, and different treatment intensities effectively reduced the fuel’s flammability. The reduction effects, presented in descending order, were as follows: medium-strength treatment > low-strength treatment > high-strength treatment > control check. In conclusion, different treatment intensities have significant effects on the flammability of the fuel, and the medium-strength treatment has the best effect. Considering the ecological and economic benefits, adopting the medium-strength treatment for the WUI to regulate the fuel is recommended.

After the period of halogenated compounds, the period of nano-structured systems, and that of phosphorus (and nitrogen)-based additives (still in progress), following the increasingly demanding circular economy concept, about ten years ago the textile flame retardant world started experiencing the design and exploitation of bio-sourced products. Indeed, since the demonstration of the potential of such bio(macro)molecules as whey proteins, milk proteins (i.e., caseins), and nucleic acids as effective flame retardants, both natural and synthetic fibers and fabrics can take advantage of the availability of several low-environmental impact/“green” compounds, often recovered from wastes or by-products, which contain all the elements that typically compose standard flame-retardant recipes. The so-treated textiles often exhibit flame-retardant features that are similar to those provided by conventional fireproof treatments. Further, the possibility of using the same deposition techniques already available in the textile industry makes these products very appealing, considering that the application methods usually do not require hazardous or toxic chemicals. This review aims to present an overview of the development of bio-sourced flame retardants, focusing attention on the latest research outcomes, and finally discussing some current challenging issues related to their efficient application, paving the way toward further future implementations.

This research studies natural rubber (NR) composite blends prepared with recycled polyethylene (PE), polyurethane waste (PU), silica (SiO2), and aluminum trihydroxide (ATH) under the proper mixing conditions using an internal mixer and a two-roll mill. The mechanical, impact, dynamic mechanical, and thermal properties, together with flammability, were investigated. NR/PU composites filled with a specific SiO2/ATH concentration resulted in excellent flame-retardant properties without using PE. Adding PE causes poor flammability, while using PU and SiO2 prevents flame extensibility of the composites. In addition, SiO2 and ATH synergistically improved both mechanical and dynamical mechanical properties. This is attributed to the reinforcement of SiO2 particles inside the matrix, whereas the ATH releases water as a flame retardant. The V-0 composites tested with UL-94 showed acceptable heat resistance, strength, and durability, making them suitable for interior and exterior applications in buildings without the lightweight requirement.

The flammability properties of polymers and polymer composites are crucial in ensuring their safe use in various applications. The development of flame-retardant technologies continues to be an active area of research to improve the fire safety of these materials. Recently, ionic liquids have been studied in the flammability properties of polymers and polymer composites. In this concise review, different types of polymers and polymer composites that are combined with ionic liquids are discovered. In addition, the preparation of polymers and polymer composites combined with ionic liquids through distinct methods is described. The additive effect of ionic liquids on the flammability properties of polymers and polymer composites is also concisely reviewed. The data demonstrated in this review contribute an extra visible knowledge of the preparation of polymers and polymer composites combined with ionic liquids and their flammability properties. In summary, certain types of ionic liquids can decrease the flammability properties of polymers and increase the flame retardancy of polymer composites.

The contradiction between flammability and packing density is the technical bottleneck for combustible smoke agent. Herein, polyurethane (PU) foams with flammability and resilience were prepared with polyol and isocyanate as raw materials by chemical foaming method, then compounded with metal powders, polytetrafluoroethylene (PTFE), phthalic annychide (PA), etc. in a certain proportion and pressed into pyrotechnic grain to obtain eco-friendly combustion aerosols with compact density of about 1.15 g/cm3. The resulting combustion smoke agent combined the advantages of PU foam and pyrotechnic with easy ignition, large smoke production, long duration and low environmental pollution. The transmittance of aerosols for 532 nm and 1064 nm lasers was close to 0, and the EMI SE reached up to 65 dB and 35 dB in GPS band and X band, respectively. In addition, the resulting pyrotechnic grains exhibited good mechanical strength and elasticity for sample 1:25, with a compressive strength of 22 MPa and an elastic modulus of 195 MPa. The resulting combustion smoke agent is expected to play a potential role in the field of electromagnetic damage and protection.