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Thermal control methods based on phase change materials have a wide range of applications, from thermal management to latent heat storage for renewable energy systems, with intermittent availability. Organic PCMs have some advantages over inorganics; however, their major drawback is flammability. In critical applications, such as buildings, electric vehicles, and aerospace applications, flammability is an issue that must be addressed in order to comply with safety standards. This review paper covers current studies assessing the PCM response to fire or excessive temperature, methods for ensuring flame retardancy, and their impact on the PCMs key characteristics: phase transition temperature range, latent heat, heat transfer rate, and compatibility with other system materials. A special focus is set on the preparation methods and the effectiveness of the flame-retardance achievement method. Some research gaps and further research directions are identified and discussed. [ABSTRACT FROM AUTHOR]

In an effort to reduce greenhouse gas emission, reduce the consumption of natural resources, and increase the sustainability of biocomposite foams, the present study focuses on the recycling of cork processing waste for the production of lightweight, non-structural, fireproof thermal and acoustic insulating panels. Egg white proteins (EWP) were used as a matrix model to introduce an open cell structure via a simple and energy-efficient microwave foaming process. Samples with different compositions (ratio of EWP and cork) and additives (eggshells and inorganic intumescent fillers) were prepared with the aim of correlating composition, cellular structures, flame resistance, and mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract Smart fire alarm sensor (FAS) materials with mechanically robust, excellent flame retardancy as well as ultra-sensitive temperature-responsive capability are highly attractive platforms for fire safety application. However, most reported FAS materials can hardly provide sensitive, continuous and reliable alarm signal output due to their undesirable temperature-responsive, flame-resistant and mechanical performances. To overcome these hurdles, herein, we utilize the multi-amino molecule, named HCPA, that can serve as triple-roles including cross-linker, fire retardant and reducing agent for decorating graphene oxide (GO) sheets and obtaining the GO/HCPA hybrid networks. Benefiting from the formation of multi-interactions in hybrid network, the optimized GO/HCPA network exhibits significant increment in mechanical strength, e.g., tensile strength and toughness increase of ~ 2.3 and ~ 5.7 times, respectively, compared to the control one. More importantly, based on P and N doping and promoting thermal reduction effect on GO network, the excellent flame retardancy (withstanding ~ 1200 °C flame attack), ultra-fast fire alarm response time (~ 0.6 s) and ultra-long alarming period (> 600 s) are obtained, representing the best comprehensive performance of GO-based FAS counterparts. Furthermore, based on GO/HCPA network, the fireproof coating is constructed and applied in polymer foam and exhibited exceptional fire shielding performance. This work provides a new idea for designing and fabricating desirable FAS materials and fireproof coatings.

The development of intelligent materials for protective equipment applications is still growing, with enormous potential to improve the safety of personnel functioning in specialized professions, such as firefighters. The design and production of such materials by the chemical modification of biodegradable semisynthetic polymers, accompanied by modern manufacturing techniques such as electrospinning, which may increase specific properties of the targeted material, continue to attract the interest of researchers. Phosphorus-modified poly(vinyl alcohol)s have been, thus, synthesized and utilized to prepare environmentally friendly electrospun mats. Poly(vinyl alcohol)s of three different molecular weights and degrees of hydrolysis were phosphorylated by polycondensation reaction in solution in the presence of phenyl dichlorophosphate in order to enhance their flame resistance and thermal stability. The thermal behavior and the flame resistance of the resulting phosphorus-modified poly(vinyl alcohol) products were investigated by thermogravimetric analysis and by cone calorimetry at a micro scale. Based on the as-synthesized phosphorus-modified poly(vinyl alcohol)s, electrospun mats were successfully fabricated by the electrospinning process. Rheology studies were performed to establish the optimal conditions of the electrospinning process, and scanning electron microscopy investigations were undertaken to observe the morphology of the phosphorus-modified poly(vinyl alcohol) electrospun mats. [ABSTRACT FROM AUTHOR]

Phosphated hydrotalcite (P-LDHs) was synthesized from steel slag and modified hydrotalcite (SDS-P-LDHs) was obtained by intercalation of P-LDHs with sodium dodecyl sulfate (SDS). P-LDHs and SDS-P-LDHs were blended with expanded graphite and ethylene vinyl acetate copolymer (EVA),to prepare EVA foam composites, respectively. The surface morphology and structure of P-LDHs and SDS-P-LDHs were characterized by XRD, XRF, FT-IR, SEM and TEM. Combined with limited oxygen index(LOI), UL-94, SEM, TG, tensile strength and elongation at break, the effects of P-LDHs and SDS-P-LDHs on the flame retardancy and mechanical properties of EVA foam composites were discussed. The results show that the addition of P-LDHs and SDS-P-LDHs significantly improves the flame retardant properties of EVA foam composites and can play a good role in charring formation. Compared with P-LDHs, SDS-P-LDHs have better compatibility with EVA matrix. When the addition amount of SDS-P-LDHs is 30%(mass fraction), the LOI reaches 27.5%, UL-94 reaches V-0 level, tensile strength and elongation at break are 2.27 MPa and 251%, respectively. The comprehensive properties of the system are optimal.

Adding flame retardant into leather is an effective way to improve the flame resistance of leather products. In this paper, a Nitrogen-Phosphorus Intumescent (NPI) flame retardant was synthesized and then added to the fatliquoring process to modify leather. The effect of NPI flame retardant on the flame-retardant properties of leather was investigated using Limiting Oxygen Index (LOI), smoke density, vertical combustion, cone calorimeter tests, and SEM. The results revealed that LOI of leather modified with NPI flame retardant increased with the increase of flame retardant. The flame and flameless combustion time of the modified leather was effectively reduced. Compared with unmodified leather, HRR of the modified leather with 6% NPI flame retardant decreased from 80.32 MJ/m2 to 63.45 MJ/m2; the peak HRR dropped from 108.71 MJ/m2 to 77.23 MJ/m2. Moreover, the fire growth index of the modified leather with 6% NPI flame retardant is close to half of that of the unmodified sample. The results certified the enhancing effect of NPI flame retardant added in the fatliquoring process on flame retardancy of leather samples.

Flame-resistant polymer composites were prepared based on polyvinyl alcohol (PVA) as a polymer matrix and a polyphosphonate as flame retardant. Oxalic acid was used as crosslinking agent. LiClO4, BaTiO3, and graphene oxide were also incorporated into PVA matrix to increase the ionic conductivity. The obtained film composites were investigated by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry and microscale combustion tests. Incorporating fire retardant (PFRV), BaTiO3, and graphene oxide (GO) into a material results in increased resistance to fire when compared to the control sample. A thermogravimetric analysis revealed that, as a general trend, the presence of PFRV and BaTiO3 nanoparticles enhances the residue quantity at a temperature of 700 °C from 7.9 wt% to 23.6 wt%. Their dielectric properties were evaluated with Broad Band Dielectric Spectroscopy. The electrical conductivity of the samples was determined and discussed in relation to the LiClO4 content. The electrical properties, including permittivity and conductivity, are being enhanced by the use of LiClO4. Additionally, a relaxation peak has been observed in the dielectric losses at frequencies exceeding 103 Hz. The electrical properties, including permittivity and conductivity, are being enhanced by the use of LiClO4. Additionally, a relaxation peak has been observed in the dielectric losses at frequencies exceeding 103 Hz. Out of the various composites tested, the composite containing 35 wt% of LiClO4 exhibits the highest alternating current (AC) conductivity, with a measured value of 2.46 × 10−3 S/m. Taking into consideration all the aspects discussed, these improved composites are intended for utilization in the manufacturing of Li-Ion batteries.

[Display omitted] • Nacre-like ternary hybrid network TA-GO/HHACP is facilely constructed. • The network shows excellent mechanical and flame resistance property. • Ultra-sensitive early fire alarm response of ∼ 1 s at temperature of 250 °C is achieved. • Ultra-long continuous fire alarming period of > 1600 s is realized. • Flame-retardant mechanisms and reliable fire warning behaviors are clarified. Graphene oxide (GO)-based intelligent fire alarm sensor (FAS) has recently been a sought-after research topic in fire prevention fields. However, it remains a challenge to facilely construct GO-based composite that simultaneously possess mechanical flexibility, excellent flame resistance, highly-sensitive temperature-responsive behavior, rapid fire response and ultra-long fire alarming durability. Here, a nacre-like ternary hybrid paper is conveniently obtained by integrating GO with hexachlorophosphazene-based multi‑hydroxyl molecule (HHACP) and tannic acid (TA) via a facile and eco-friendly water evaporation-induced self-assembly method. The resultant composite paper (TA-GO/HHACP) exhibits mechanically flexible property with tensile strength of 103.7 MPa and toughness of 1.51 MJ/m3, comparable to 2.52 and 5.39 times higher than those of pure GO paper. Further, the TA-GO/HHACP paper displays excellent nonflammability and high-temperature resistance that can withstand continuous butane flame attack (∼ 1200 °C), resulting in ultra-long sustained alarming period of > 1600 s under an open fire. More importantly, benefiting from its rapid electrical resistance reduction capability, such TA-GO/HHACP paper demonstrates ultra-fast fire-triggered response time of ∼ 0.6 s, and ultra-sensitive early fire alarm responses to abnormal high temperatures during pre-combustion process, e.g., ∼ 1 s at 250 °C and ∼ 19 s at 200 °C, respectively, outperforming the best reported GO‑based FAS counterparts. This work provides an inventive paradigm to develop high-performance GO-based intelligent materials with reliable and sensitive early fire-warning function. [ABSTRACT FROM AUTHOR]

Thermal control methods based on phase change materials have a wide range of applications, from thermal management to latent heat storage for renewable energy systems, with intermittent availability. Organic PCMs have some advantages over inorganics; however, their major drawback is flammability. In critical applications, such as buildings, electric vehicles, and aerospace applications, flammability is an issue that must be addressed in order to comply with safety standards. This review paper covers current studies assessing the PCM response to fire or excessive temperature, methods for ensuring flame retardancy, and their impact on the PCMs key characteristics: phase transition temperature range, latent heat, heat transfer rate, and compatibility with other system materials. A special focus is set on the preparation methods and the effectiveness of the flame-retardance achievement method. Some research gaps and further research directions are identified and discussed.

The objective of this study is to develop polybenzoxazine‐silica nanocomposite systems endowed with greater thermal and fire performance. For this purpose, the 3‐aminopropyltrimethoxysilane and bisphenol A‐based benzoxazine (BA‐3aptms) was synthesized. Also, smooth and spherical silica nanoparticles of 50 nm size were prepared following the Stöber's method. The influence of the nanoparticle size and geometry on the properties (laminar morphology, thermal, dynamic‐mechanical, hydrophobicity, and flame retardancy) of the polybenzoxazine/polysilsesquioxane material was investigated. Also, nanocomposites from the conventional benzoxazine (BA‐a) and SiO2 nanoparticles were synthesized for comparative purposes. The addition of nanoparticles in both polybenzoxazines improved the mechanical, thermal and flammability properties. Likewise, the presence of these nanoparticles conferred to the material a more hydrophobic surface (contact angle around 95°). Particularly, the Pr(BA‐3aptms)/NP nanocomposites presented better properties than the BA‐a‐based systems, due to the presence of laminar‐oriented polysilsesquioxane networks chemically bonded to the silica nanoparticles at nanoscale. [ABSTRACT FROM AUTHOR]

Highlights: Graphene oxide-based hybrid networks were fabricated via introducing multi-amino molecule with triple roles (i.e., cross-linker, fire retardant and reducing agent). The optimized hybrid network with mechanically robust, exceptional intumescent effect and ultra-sensitive fire alarm response (~ 0.6 s) can be used as desirable smart fire alarm sensor materials. Exceptional fire shielding performances, e.g., ~ 60% reduction in peak heat release rate and limiting oxygen index of ~ 36.5%, are achieved, when coated such hybrid network onto combustible polymer foam. Smart fire alarm sensor (FAS) materials with mechanically robust, excellent flame retardancy as well as ultra-sensitive temperature-responsive capability are highly attractive platforms for fire safety application. However, most reported FAS materials can hardly provide sensitive, continuous and reliable alarm signal output due to their undesirable temperature-responsive, flame-resistant and mechanical performances. To overcome these hurdles, herein, we utilize the multi-amino molecule, named HCPA, that can serve as triple-roles including cross-linker, fire retardant and reducing agent for decorating graphene oxide (GO) sheets and obtaining the GO/HCPA hybrid networks. Benefiting from the formation of multi-interactions in hybrid network, the optimized GO/HCPA network exhibits significant increment in mechanical strength, e.g., tensile strength and toughness increase of ~ 2.3 and ~ 5.7 times, respectively, compared to the control one. More importantly, based on P and N doping and promoting thermal reduction effect on GO network, the excellent flame retardancy (withstanding ~ 1200 °C flame attack), ultra-fast fire alarm response time (~ 0.6 s) and ultra-long alarming period (> 600 s) are obtained, representing the best comprehensive performance of GO-based FAS counterparts. Furthermore, based on GO/HCPA network, the fireproof coating is constructed and applied in polymer foam and exhibited exceptional fire shielding performance. This work provides a new idea for designing and fabricating desirable FAS materials and fireproof coatings. [ABSTRACT FROM AUTHOR]

Burning of plastics present a serious problem for both our health and safety when applied in advanced applications. Based on the above argument, there is need to enhance the flammability resistance of polymers in order to meet the required flammability standards. Various flame‐retardant fillers are incorporated into polymers in order to provide a protection against heat into the system and inhibit the diffusion of volatile materials out of the polymer composite system. Different flame‐retardant fillers including phosphorus‐based materials, carbon‐based flame retardants, and inorganic hydrated flame‐retardant fillers have been added into polymers in order to improve the flame retardancy of the plastics. Amongst the abovementioned flame‐retardant fillers, inorganic hydrated fillers have gained popularity, especially magnesium hydroxide (Mg(OH)2) due its high heat absorption capacity, less smoke release, and non‐toxic, as a result environmentally friendly flame‐retardant filler. However, an effective content of magnesium hydroxide for better flammability retardancy is approximately 60 wt%, which happens to deteriorate the mechanical properties of the magnesium hydroxide/polymer composites. In order to try and compensate for reduction in mechanical properties and improve the flame retardancy of the composites at the same time, magnesium hydroxide is incorporated with another flame‐retardant fillers. This review article covers an in‐depth discussion on the effect of magnesium hydroxide modification, synergistic effect with other fillers, particle size of the magnesium hydroxide, and the effect of compatibilizer(s) on both mechanical and flammability properties of magnesium hydroxide reinforced polymer composites. [ABSTRACT FROM AUTHOR]

Cellulose is now considered as an appealing environment friendly material for the development of sustainable separators for rechargeable batteries. This study thus aims to develop high performance paper based ceramic separators with superior electrolyte wettability (>170 %), high thermal stability (>200 °C) and excellent flame safety. While developing paper based ceramic separator, extensive studies are carried out to understand thenature and functionality of different nano-structured ceramic materials (Al 2 O 3 , BaTiO 3 and ZrO 2) impregnated in paper matrix. Nano-ZrO 2 facilitates an effective pathway for Li +-ion transport (t Li + = 0.51), whereas BaTiO 3 and Al 2 O 3 ceramics show moderate Li +-ion transport properties (t Li+ of 0.29 and 0.30 respectively). Electrochemical Impedance Spectroscopy (EIS) measurement clearly reveals that ZrO 2 exhibits more interfacial compatibility with the electrodes (MCMB and LiNi 1/3 Mn 1/3 Co 1/3 O 2) compared to the other two ceramic separators during full cell operation. The developed paper separators show excellent electrochemical properties in terms of cycling (tested 300 cycles), multi-electrode compatibility and rate capabilities at different current densities of 0.1–1.2 mAcm−2. The pre- and post-electrochemical EIS data reveal that ZrO 2 based impregnation offers significantly lower charge transfer resistance compared to the other two separators. The study thus demonstrates a real promise for its successful application in Li-ion battery towards achieving sustainability and safety. [Display omitted] • Sustainable, flexible and high safety ceramic based paper separators for LIBs. • Separators were developed using easy to scale up wet-coating process. • Ceramic impregnation affects physical and electrochemical properties of the separators. • Paper separators show superior electrolyte wettability and high thermal stability. • Better electrochemical performances and flame safety are other important advantages. [ABSTRACT FROM AUTHOR]

The mechanical shock and thermal damage generally exist together in hazardous environment, whereas traditional single protective materials are difficult to achieve all-round protection under extreme environment. Herein, to realize the integration of multifunctional abilities about impact resistance, flame-retardant and sensing performance, a "solid-liquid host-guest" structural shear thickened composite sponge is proposed, which flame-retardant shear thickening fluids with an extraordinary thickening ratio of 2183.95 % continuously disperse in 3D sponge matrix. The resulting composite sponge effectively attenuates the impact force by nearly 80 % with the thickness of only 4 mm via a cooperation between the effect of shear hardening and structure densification. Meanwhile, after burning on the alcohol flame for 12 s, the composite sponge with 7 wt.% fire-retardant additive maintains a complete morphology and realizes self-extinguishing with a reliable flame-retardant ability. Attributed to the good electrical conductivity of shear thickening fluid, the composite sponge serves favorably in human body monitoring, impact sensing and fire warning. In a word, this multifunctional lightweight composite sponge is expected to realize the integration of early warning and protection, which is a competitive candidate material for the intelligent protection in complex environments. [Display omitted] • A new type of conductive shear thickening fluid was prepared. • The sensing performance endows P-STF sponge with human body monitoring function. • The P-STF sponge protects against both impact and thermal hazards. • The P-STF sponge achieves the integration of protection and early warning. [ABSTRACT FROM AUTHOR]

The development of intelligent materials for protective equipment applications is still growing, with enormous potential to improve the safety of personnel functioning in specialized professions, such as firefighters. The design and production of such materials by the chemical modification of biodegradable semisynthetic polymers, accompanied by modern manufacturing techniques such as electrospinning, which may increase specific properties of the targeted material, continue to attract the interest of researchers. Phosphorus-modified poly(vinyl alcohol)s have been, thus, synthesized and utilized to prepare environmentally friendly electrospun mats. Poly(vinyl alcohol)s of three different molecular weights and degrees of hydrolysis were phosphorylated by polycondensation reaction in solution in the presence of phenyl dichlorophosphate in order to enhance their flame resistance and thermal stability. The thermal behavior and the flame resistance of the resulting phosphorus-modified poly(vinyl alcohol) products were investigated by thermogravimetric analysis and by cone calorimetry at a micro scale. Based on the as-synthesized phosphorus-modified poly(vinyl alcohol)s, electrospun mats were successfully fabricated by the electrospinning process. Rheology studies were performed to establish the optimal conditions of the electrospinning process, and scanning electron microscopy investigations were undertaken to observe the morphology of the phosphorus-modified poly(vinyl alcohol) electrospun mats.

Taking into account numerous results from the literature, an in-depth exploratory study on the chemical gradients in the rise (or depth) direction was performed on polyisocyanurate rigid (PIR) foam insulation panels using ATR-FTIR spectroscopy. In particular, it was found that the isocyanurate/phenyl ratio is a quick and effective technique for providing an indication of the level of trimer conversion within each sample. More importantly, a detailed analysis of the C–N stretching vibration of the isocyanurate ring as a function of depth revealed a linear decrease in the frequency peak maximum with the increase in the isocyanurate ratio for all investigated PIR foams. This result suggests for the first time that the position (frequency) of peak maximum (C–N stretching of isocyanurate ring) may be used to quantify the extent of isocyanurate formation without the issues linked to the use of absorbances. It is proposed that this reduction in the frequency of the C–N stretching vibration of isocyanurate ring reflects the decrease in hydrogen bonding between N–H of urethane group and CO within the isocyanurate ring when the isocyanurate content increases (lower mobility associated with higher level of cross-linking). The heterogeneity of the isocyanurate content was physically confirmed by investigating the flammability of the foam samples taken at different positions in the rise direction (z-axis).

In order to develop a fabric with excellent flame resistance function, antistatic function, moisture absorption and breachability, the polysulfonamide (PSA) fiber and the flame retardant viscose (FRV) fiber were blended. Meanwhile, the conductive filaments were used as the core yarn, and then they w'ere made into the core-spun yarn and the fabric at different blending ratios of PSA/FRV. The effects of the blending ratio of PSA/FRV on the mechanical properties and the evenness of the yarn were studied. The effects of the blending ratio of PSA/FRV on mechanical properties, flame retardant properties, antistatic properties, moisture permeability and drape of the fabric were analyzed. With the increase of the blending ratios of PSA/FRV, the strength and the elongation of the core-spun yarn increased firstly and then decreased. Moreover, the evenness of the core-spun yarn was improved, the fabric strength increased firstly and then decreased, the flame resistance decreased, and the antistatic performance improved. These results proride an important basis for the preparation and wide application of fabrics made of PSA/FRV/conductive filament. [ABSTRACT FROM AUTHOR]

[Display omitted] • The multifunctional conductive HPCF was prepared using a layer-by-layer deposition method. • The resulted HPCF possess great superhydrophobic and flame retardancy. • The obtained HPCF can transmit distress signals and realize water rescue. • The HPCF shows rapid detection response for flame within 1 s. • The smart fabric is useful for multifunctional wearable electronic textile. Smart fabrics provide considerable inspiration for the construction of wearable electronic devices due to their excellent skin affinity and breathability. However, the limited tolerance to high humidity environments and the flammable nature of fabrics impedes broader practical applications. In this paper, by an advanced and effective method, phytic acid doped (PA-) polyaniline (PANI) was polymerized in-situ on cotton fabric deposited by carbon black (CB), and then modified by non-fluorine hydrophobic particles, a flexible breathable fabric-based strain sensor (HPCF) with ultrahigh moisture resistance, flame retardancy and environmental resistance was successfully prepared. The obtained sensor shows high sensitivity (16.14 kPa−1) in the detection range of 0–2 kPa, fast response/recovery time (82/40 ms) and high cycle stability (>10,000 cycles). Thanks to its excellent hydrophobicity (WCA = 153°) and flame retardancy properties, the material enables the detection of human movement (such as finger/wrist/elbow/knee/foot movement) under a variety of harsh conditions (extremely high temperatures, underwater, acid, alkali, salt and blown sand environments). More importantly, it can be further applied to remote detection of potentially dangerous scenarios. HPCF can successfully transmit the Morse code signals of "SOS" and "HELP" sent by drowning people, and realize water rescue. In case of fire, it serves as a fire warning sensor to realize agile (1 s) fire alarming. The highly sensitive and versatile HPCF fabric sensor enables physical condition monitoring for fire and rescue personnel working in high temperature and humidity environments, which is of great value for all human activities carried out in harsh environments. [ABSTRACT FROM AUTHOR]

Flame-retardant silane-grafted-graphene oxide (silane-GO) papers are fabricated via a green and versatile silane-assisted assembling strategy, and their use as early fire alarm sensors are investigated. Different silane molecules with alkoxy groups can react with GO in aqueous solution via hydrolysis and condensation reactions and thus assemble into the aligned silane-GO papers. The silane-GO papers exhibit good mechanical flexibility, strong acidic/alkaline tolerance, excellent flame resistance and improved thermal stability at low silane content in comparison with pure GO paper. Structure observation and analysis disclose that a compact nano-silica protective layer transformed from the grafted silane molecules during combustion is formed to inhibit the thermal degradation of GO sheet effectively. Furthermore, the insulating silane-GO paper can be thermally reduced into the conductive reduced GO network after encountering high-temperature or flame situation, thus providing ideal early fire alarm response, i.e. rapid flame detecting response time of ∼1.6 s and fire early warning response of ∼5 s when attach on the heat resistor. These results suggest that the silane-GO papers are promising for development of advanced materials as smart sensors in early fire alarm applications. A facile and green silane-assisted assembling technique was developed to fabricate flame-retardant graphene oxide papers, showing fast flame detection and ideal early warning response. Image 1 • A facile silane-assisted assembling strategy was developed to fabricate flame-retardant graphene oxide (silane-GO) papers. • Different silane molecules with alkoxy groups were assembled well onto the aligned silane-GO papers. • The silane-GO papers exhibited good mechanical flexibility, strong acidic/alkaline tolerance, and excellent thermal stability and flame resistance. • The related flame-retardant mechanisms were analyzed and discussed. • The silane-GO papers showed fast fire alarm response due to temperature-triggered sensitive resistance transition, showing promising for fire safety and prevention. [ABSTRACT FROM AUTHOR]

Flame retardant and visible light-activated Fe-doped TiO 2 thin films were anchored to wood surfaces by a facile precipitation method for the photocatalytic degradation of gaseous formaldehyde. All of the as-prepared TiO 2 thin films exhibited the anatase crystal structure and grew on the wood surfaces by the aggregation of nanoparticles with diameters ranging from 11 to 16 nm. The UV–vis diffuse reflectance spectroscopy (UV–vis DRS) results showed that the presence of a small amount of iron ions in the TiO 2 matrix could significantly extend the optical responses in the UV to visible region. Compared to the pure TiO 2 /wood samples, the Fe-doped TiO 2 /wood samples exhibited higher photocatalytic activities under visible light irradiation. The optimum n Fe / n Ti molar ratio was 2.0 at. %. The electron spin resonance (ESR) tests further confirmed that the active oxygen species of OH and O 2 – that were generated on the Fe-doped TiO 2 /wood samples under visible light irradiation are responsible for the degradation of formaldehyde. The Fe-doped TiO 2 samples also exhibited high stability and reusability after 6 cycles. Additionally, the limiting oxygen index of the original wood increased from 24.8% to 33.9% after it was coated with Fe-doped TiO 2 thin films, indicating a significant improvement in its flame resistance. [ABSTRACT FROM AUTHOR]

In this study, medium-density coir fiberboard samples treated with fire-retardant (FR) solutions were found to be effective in resisting fires. This study sought the most favorable combination of FR boron solution for imparting flame resistance to coir fiberboards. The samples were chemically treated with FR solutions of various combinations of borax and boric acid. The treated samples showed substantial improvements in their resistance to flammability and flame penetration time, a reduced rate of burning, and a higher resistance to spread of flame. A regression analysis was performed to determine the relationship between the weight percentage of FR boron present in the solution and the flame resistance characteristics of treated coir fiberboards, in which the predictions were found to be accurate, within ± 3%. The study concluded that any difference in the weight percentage of FR boron in the solution affected the flame resistance, and a solution that contained 35% boron imparted maximum fire resistance to coir fiberboard samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A 5-hydroxymethyl-2-furaldehyde derived epoxy resin monomer (HMF-PDMS-EP) was developed. • The bio-based epoxy system showed a record T g of 207 °C, high strength and modulus. • The bio-based epoxy system showed satisfactory intrinsic flame retardancy. • The bio-based epoxy system showed recyclability in carbon fiber composite. A new renewable material, comprising a Schiff base epoxy thermoset derived from furan derivatives, was successfully synthesized. This innovative material not only possesses remarkable carbon fiber recyclability but also exhibits favorable mechanical properties and flame retardancy. After being cured with the bio-based curing agent, 5,5′-methylenedifurfurylamine, the cured Schiff base epoxy thermoset exhibited an ultra-high char yield of 54% and a glass transition temperature of 207 °C. Compared to bisphenol A epoxy resin, it achieved a 100% higher yield. Furthermore, the cured Schiff base epoxy thermoset demonstrated a high storage modulus (at 30 °C) of 2695 MPa and a tensile modulus of 60 MPa, surpassing bisphenol A epoxy resin. Remarkably, the exceptional structure of the Schiff base epoxy thermoset imparted intrinsic flame retardancy, resulting in a V-0 rating in the UL-94 test. The thermoset also exhibited considerable recyclability in carbon fiber composites due to its Schiff base network. Moreover, it could be nondestructively and quickly recycled under mildly acidic conditions, enabling efficient recycling of the carbon fiber composites. [ABSTRACT FROM AUTHOR]

This study evaluates the efficiency of non-flammable functional underwear used as a secondary heat barrier in extreme conditions. Five groups of knitted fabrics were analysed for flame resistance and selected physiological properties (water vapour permeability, air permeability, thermal resistance and liquid moisture transport by moisture management transport). The results indicated similar levels of flame resistance for the materials tested but show important differences in terms of physiological characteristics, namely liquid moisture transport, which influences the safety and comfort of protective clothing.

In this work, aluminum hydroxide aerogel was successfully assembled on polysulfonamide fabrics by sol-gel forming method to improve the thermal insulation and flame resistance properties. The presence of aluminum hydroxide aerogels assembled on the surface of polysulfonamide fabrics was verified by the scanning electron microscopy. The aerogel was crystalized in γ-AlOOH boehmite form characterized by X-ray powder diffraction. The heat insulation and flame resistance of polysulfonamide fabrics were improved by coating aluminum hydroxide aerogels. When the molar ratio of propylene oxide to aluminum chloride hexahydrate was 4:1, the prepared aluminum hydroxide aerogel marked as S-2 had the largest pore volume with the value of 2.33 cm/g, the corresponding apparent density was 0.172 g/cm, the specific surface area was 392 m/g, the average pore diameter was 18.6 nm, and it gave the best thermal insulation property. Compared with the original polysulfonamide fabric, the thermal conductivity of the composite fabric was decreased from 0.0513 to 0.0301 W/(m·K). When the molar ratio of propylene oxide to aluminum chloride hexahydrate was 3:1, the prepared aluminum hydroxide aerogel marked as S-1 had the smallest pore volume with the value of 0.72 cm/g, the corresponding apparent density was 0.645 g/cm, the specific surface area was 293 m/g, the average pore diameter was 10.9 nm, and it gave the best flame resistance property. Compared with the original polysulfonamide fabric, the vertical burning damage length was shorted from 4.90 to 1.30 cm. Graphical abstract: [ABSTRACT FROM AUTHOR]

As tunnels are now longer and built more frequently, fire safety in tunnels has become a major issue throughout the world. The objective of this study is to investigate the flame resistance of warm-mix asphalt mixtures with flame retardants through a comprehensive testing program. In this study, a compound flame retardant (FR) was added to the asphalt and warm-mix asphalt. The comprehensive testing program included the flash point test and oxygen index test of the asphalt binder, the combustion test of loose and compacted mixtures, and a bench scale apparatus for combustion testing of asphalt mixtures in order to understand the flame resistance of the asphalt and mixtures. The results of the asphalt binder tests indicate that FR has no significant effect on the flash point but has an obvious effect on the fire point, and FR asphalt requires more oxygen because the FR prevents it from burning. During various combustion tests, the FR reduced the flame, lessened the smoke, and lowered the temperature but noticeably increased the burning time. It was noticed that the structural integrity of the burned FR mixture samples is preferable to the mixture without FR. The bench scale apparatus for combustion testing shows that the ignition time is extended, both the heat release and smoke for the FR mixtures are noticeably decreased, and both the carbon monoxide (CO) and carbon dioxide (CO2) emissions are reduced. This means FR mixtures have better flame resistance and will have less potential for environmental pollution. Moreover, the results also show that a warm-mix asphalt additive has little effect on the flash point, fire point, or oxygen index of the asphalt. It also has little effect on the burning time and the flame height of loose mixtures. Because the warm-mix asphalt additive aids combustion, it decreases the maximum temperature and mass loss of the compacted mixtures during the firing process. It also shortens the ignition time and decreases the released heat, the total smoke, and the release of CO and CO2. Thus, the flame resistance of warm-mix asphalt with FR is the best due to the combined effect of the FR and the warm-mix asphalt additive, which means that the combination of modified asphalt is preferable for asphalt pavement in tunnels. [ABSTRACT FROM AUTHOR]

Conveyor belts are used for a long period of time in the industry branches where potentially explosive atmospheres could occur. Dangerous phenomena which can be in direct connection with the use of conveyor belts are the ones regarding: - sparks influence over the coating layer and/or resistance internal structure of the stopped conveyor belt; - propagation of a flame along the length of a conveyor belt that was exposed to a energy source relative high like a fire or due to blockage of a conveyor belt as a result of the driving mechanism still operating, that generate a local heating of the conveyor belt in contact with the driving drum, rollers or any other heating source generated by friction. Determining the safety parameters characteristic of the conveyor belts by employing test methods allows assessment of the safety level as well as certification of their explosion protection quality when used in environments with explosion danger.

A series of polyurethane-polyisocyanurate (PU-PIR) foams synthesized from PET-waste-derived aromatic polyester polyols (APP) was studied using thermogravimetric analysis, Cone calorimeter and burning tests. The effect of chemical structure of the APP containing fragments of glycerol, adipic acid, poly(propylene glycol) or hexanediol on thermal stability and flame resistance of the PU-PIR foams was elucidated. PU-PIR foams prepared from APP containing fragments of glycerol and/or adipic acid had higher thermal stability and lower weight loss at 330 °C. The foams based on APP derived from industrial PET waste were characterized by relatively low heat release and low smoke production. The presence of the fragments of the functional additives glycerol and/or adipic acid in the structure of APP used for production of PU-PIR foams, marginally decreased the heat release and slightly increased the smoke production.http://dx.doi.org/10.5755/j01.ms.17.3.588

[Display omitted] • Liquid monomers enable bulk polymerization via one-pot parallel reactions. • The new strategy readily affords novel interpenetrating polymer networks. • The resin fluctuates with hardeners showing a twist-stacked or planar weave matrix. • The viscoelastic, dielectric, mechanical behaviors and flame retardancy are enhanced. • Aerobic or anaerobic pyrolysis selectively favors the IPN upcycling into graphene. The 5-hydroxymethylfurfural, honokiol, and magnolol are converted into sustainable epoxy monomers, i.e. , 5,5′-(((3′,5-diallyl-[1,1′-biphenyl]-2,4′-diyl)bis(oxy))bis- (methyl-ene))bis(2-((oxiran-2-ylmethoxy)methyl)furan) (MGHF) and 5,5′-(((5,5′-diallyl-[1,1′-biphenyl]-2,2′-diyl)bis(oxy))bis(methylene))bis(2-((oxiran-2-ylmethoxy)- methyl)furan) (MGMF), and they are finally cured by 3,3′-diamino diphenylsulfone (33DDS) and 4,4′-diamino diphenylsulfone (44DDS), thus affording novel interpenetrating polymer networks (IPN). Interestingly, 33DDS induces a twist-stacked structure, whereas 44DDS provides a planar weave matrix. As to the twist-stacked layout MGMF/33DDS, it behaves a superhigh storage modulus (∼5.04 GPa), a high phase transition temperature (T g , 222.7 °C), and an elevated onset temperature (T d5 , 362.8 °C). For planar weave arrays, MGHF/44DDS shows the highest values in T g (224.9 °C), lap shear strength (∼20.4 MPa), hardness (∼508 MPa), and reduced Young's modulus (∼6.06 GPa). Furthermore, MGMF/44DDS shows an excellent dielectric property (11.15, 0.02) (∼1 kHz, 25 °C) and a moderate thermal conductivity (0.355 W (m·K)−1) alonging with increased flame retardancy. Besides, those biobased epoxy resin wastes are reclaimable through aerobic or anaerobic pyrolysis. Anaerobic pyrolysis of planar weave networks selectively yields more doped graphene, whereas similar event readily happens to the aerobic pyrolysis of the twist-stacked polymers. In view of these reported advantages, this novel strategy opens new avenues for multifunctional epoxy resins. [ABSTRACT FROM AUTHOR]

[Display omitted] • STF is prepared by ionic liquids and SiO 2 with good thermal stability. • The STF/Kevlar composite has good high temperature resistance. • The STF/Kevlar composite protects against both impact and thermal hazards. • The composite has a wide application prospect in extreme environments. The impact and thermal damage in extreme environments generally exist together. In this context, the design of safety protection materials ought to consider not only the single impact protection performance, but also thermal stability and flame resistance. In order to simultaneously achieve the impact resistance, thermal stability and flame resistance properties, a flexible and lightweight shear-hardened composite material (STF/Kevlar) was prepared by impregnating and drying shear thickening fluid (STF) on Kevlar fabric. Due to the favorable shear thickening performance of shear thickening fluid, STF/Kevlar composite material can increase the maximum yarn pull-out force of the fabric yarn from 3.3 N to 16.3 N with the impregnation weight gain of 55 wt%. Moreover, in bullet impact experiment, a single layer of STF/Kevlar fabric can nearly double the time it takes a bullet to penetrate pure Kevlar fabric. Additionally, STF/Kevlar composite material exhibits significant flame resistance as well. The limit oxygen index can reach 32 %, and after 30 min high temperature treatment at 400 °C, the composite still maintains good mechanical property and flexibility. This multi-functional composite material along with the performance of resisting both mechanical shock and thermal damage in extreme environments is expected to broadly apply in the field of lightweight protection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Obtention of novel thermosetting copolymers with high-performance applications. • Polysilsesquioxane-based structures enhance the mechanical and thermal resistance of the polymeric matrices. • Hybrid polybenzoxazine/polysilsesquioxane structures show laminar nanosized morphology. • Benzoxazines results in good curing agents for epoxy resins to prepare benzoxazine/epoxy copolymers. This work focuses on the development of novel thermosetting systems derived from a siloxane-based benzoxazine hybrid precursor [Pr(BA-3aptms)], a conventional benzoxazine (BA-a) and a commercial epoxy resin (DGEBA) based on bisphenol A, as a strategy to prepare benzoxazine/benzoxazine and epoxy/benzoxazine copolymers with different amounts of polysilsesquioxanes in their chemical structure. The effect of the siloxane composition on the morphology was investigated, and their influence on the thermal, dynamo-mechanical and flammability properties was elucidated. The obtained results allowed to conclude that an increase of the BA-a or DGEBA content in the copolymers, considerably affects the morphology of the materials. In this sense, the laminar arrangement changed to a nanocluster arrangement when the contents of Si were below 17% w/w for the epoxy/benzoxazine and below 10% w/w for benzoxazine/benzoxazine systems, respectively. Also, the thickness of the organic sheets in the matrices was increased when increasing the content of BA-a or DGEBA in the materials. In addition, the incorporation of the polysilsesquioxane-based precursor in the crosslinked materials improved the investigated properties, such as: thermal, mechanical and flame resistance, and hydrophobic behavior. [ABSTRACT FROM AUTHOR]

Flame-resistant polymer composites were prepared based on polyvinyl alcohol (PVA) as a polymer matrix and a polyphosphonate as flame retardant. Oxalic acid was used as crosslinking agent. LiClO 4 , BaTiO 3 , and graphene oxide were also incorporated into PVA matrix to increase the ionic conductivity. The obtained film composites were investigated by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry and microscale combustion tests. Incorporating fire retardant (PFRV), BaTiO 3 , and graphene oxide (GO) into a material results in increased resistance to fire when compared to the control sample. A thermogravimetric analysis revealed that, as a general trend, the presence of PFRV and BaTiO 3 nanoparticles enhances the residue quantity at a temperature of 700 °C from 7.9 wt% to 23.6 wt%. Their dielectric properties were evaluated with Broad Band Dielectric Spectroscopy. The electrical conductivity of the samples was determined and discussed in relation to the LiClO 4 content. The electrical properties, including permittivity and conductivity, are being enhanced by the use of LiClO 4 . Additionally, a relaxation peak has been observed in the dielectric losses at frequencies exceeding 103 Hz. The electrical properties, including permittivity and conductivity, are being enhanced by the use of LiClO 4 . Additionally, a relaxation peak has been observed in the dielectric losses at frequencies exceeding 103 Hz. Out of the various composites tested, the composite containing 35 wt% of LiClO 4 exhibits the highest alternating current (AC) conductivity, with a measured value of 2.46 × 10 -3 S/m. Taking into consideration all the aspects discussed, these improved composites are intended for utilization in the manufacturing of Li-Ion batteries.