Fire Safety Properties Research Articles

Evaluation of fire-retardant biocomposites exposed to various heat fluxes at medium and large scales

This study aims to enhance the understanding of fire behavior in biosourced composite materials for potential aeronautics and automotive applications. Experimental tests include NexGen burner trials for Federal Aviation Administration fire certification and cone calorimeter tests on a medium scale. The research also explores the development of biosourced composite materials, addressing the non-biodegradability of synthetic counterparts and contributing to the understanding of their physical and chemical characteristics under varying heat flux densities (20, 35, and 50 kW/m2). The heat fluxes of 25, 35, and 50 kW/m2 were selected to provide a range of moderate- to high-intensity heat exposures that are relevant for assessing the thermal performance and fire behavior of biocomposite materials. The composites were fabricated using the Vacuum-Assisted Resin Transfer Molding method, augmented with an intumescent flame-retardant layer to bolster their fire safety attributes. The parametric study focused on the fire performance index, the fire growth index, the mass loss, the gas emission species, the surface temperature of the front face of the sample using a Telops infrared camera, and the gaseous emissions obtained for each test configuration. The sample dimensions are 100 × 100 × 5 mm3 for the cone calorimeter and 500 × 500 × 5 mm3 for the NexGen burner. Our experimental findings provide a detailed quantitative analysis of their fire performance, highlighting the significant variance in thermal properties and degradation behavior contingent on fiber type and heat flux exposure. Time-to-ignition ranged from 144.9 to 36 s for flax composites and 125 to 32.5 s for banana composites across the tested heat flux densities. The peak heat release rate was notably higher for banana composites (753.1–908.6 kW/m2) compared to flax (495.4–823 kW/m2). This study underscores the critical dependency of thermal and fire safety properties on composite material composition and heat flux exposure, providing valuable insights for the development of safer, biosourced composite materials.

Rapid Growth of Ag Nanoparticles on MoS2 Surfaces: An Effective Method to Improve Fire Safety and Mechanical Properties of Ethylene‐Vinyl Acetate Composites

ABSTRACTTwo‐dimensional molybdenum disulfide (MoS2) nanosheets are promising nanofillers for improving the properties of polymers, but low‐cost, facile and green methods need to be further explored to meet the requirements for large‐scale production of modified MoS2 nanosheets. Here, we developed a new idea that is, to prepare MoS2@Ag by modifying the surface of MoS2 using radiative reduction. It is noteworthy that the modified MoS2@Ag can effectively improve the mechanical strength of ethylene‐vinyl acetate (EVA) composites. In addition, the addition of MoS2@Ag was able to substantially improve the flame‐retardant properties of EVA, resulting in a significant reduction in the amount of heat and smoke released from its combustion. When two parts of MoS2@Ag were added, the peak heat release rate and total smoke release of EVA/2.0MoS2@Ag composites were reduced by 29.7% and 39.2%, respectively, compared with that of pure EVA. At the same time, the toxic gases (e.g., CO) produced by the combustion of EVA composites were significantly reduced, which indicates an improvement in their fire safety.

Design, construction and mechanism of highly efficient flame retardant, UV shielding and transparent thermoplastic polyurethanes

The rapid development of 5G communication and new energy poses great challenges to the fire safety, UV resistance, and transparent properties of TPU composites. In this study, a novel and multi-functional flame retardant ((diphenylphosphoryl)azanediyl)bis(ethane-2,1-diyl) bis(diphenylphosphinate) (DPEP) containing multiple flame retardant groups and polyaromatic structure was innovatively designed. The prepared TPU/DPEP composites exhibited excellent fire safety, UV shielding, mechanical and transparent properties. 4 wt% DPEP enabled TPU to pass the UL-94 V-0 rating and improved the LOI to 29.6 %. Compared to pure TPU, the heat release rate and total heat release of TPU/4 wt% DPEP were decreased by 29.06 % and 13.24 %. Meanwhile, TPU/DPEP composites achieved 100 % UV shielding at UV-B wavelengths and up to 68.77 % UV isolation at UV-A wavelengths. Due to the structural similarity and processing meltability, DPEP exhibited good dispersion and compatibility in TPU matrix. TPU/DPEP retained almost the same mechanical and transparent properties as pure TPU. The condensed and gas phase analysis indicated that the flame retardant mode of DPEP was mainly dominated by flame retardant inhibition and the barrier effect of the carbon layer. Compared with the reported flame retardant TPU composites, the TPU/DPEP composites achieved a relatively optimal balance between efficient flame retardant, mechanical, UV shielding, and transparent properties, demonstrating great application prospects in the emerging fields.

Fire safety and high mechanical strength epoxy resin enabled by a bis-benzimidazole-primed phenyl phosphonic acid

Preparation of fire safety and high mechanical strength epoxy resin (EP) has become a hot topic for its valuable applications in construction and other fields. Here, bis-2-aminobenzimidazole-modified phenyl phosphonates (PP-BMI) with symmetric structures were synthesized by a simple chemical modification strategy, and its fine structure and composition have been thoroughly characterized. Due to the multifaceted functions of PP-BMI in both gaseous and condensed phases, EP composite with 5 wt% PP-BMI reached a UL-94 V-0 rating and high LOI of 34.3 %. The excellent fire safety of EP/5PP-BMI was further verified with a significant reduction of 57 %, 52 % and 46 % in peak heat release rate (PHRR), total heat release (THR) and peak CO production (P-COP), respectively, compared to the original EP. The flame retardancy of PP-BMI on EP can be attributed to the dilution of non-combustion gases, free radical trapping and catalytic charring functions. More importantly, PP-BMI can further enhance the mechanical properties of EP, which is closely related to the interaction between PP-BMI and EP matrix. Furthermore, EP/PP-BMI composites have good resistance to acids and alkalis, ensuring long-lasting flame retardancy and mechanical properties. This work provides a new strategy for realizing epoxy composites with high fire safety and excellent mechanical properties in construction and multifaceted areas.

Novel Aryl Phosphate for Improving Fire Safety and Mechanical Properties of Epoxy Resins.

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

Sustainable lignin-based high-efficiency flame-retardant epoxy resins with excellent mechanical properties

As an abundant natural aromatic polymer, how to realize the high-value utilization of lignin (LA) is still a difficult problem. Herein, a sustainable flame retardant (LA@APP) was synthesized through hydrogen bonding interactions between LA and ammonium polyphosphate (APP), then flame retarded alone epoxy resin (EP/LA@APP). With loading of 6 wt% LA@APP, the LOI of EP/LA@APP6 rose to 27.9 % and achieved UL-94 V0 rating. Meanwhile, EP/LA@APP6 presented a 63.5 % reduction in peak of heat release rate (pHRR) and an 51.3 % decrease in peak of smoke production rate (pSPR). LA@APP could promote the EP composites to form the denser and more continuous expanded charring residuals than APP during the combustion process, effectively shielding the underlying epoxy substrate and thus enhancing fire safety. Additionally, the shell layer of LA@APP, abundant in hydroxyl groups and methoxy groups, effectively improved the compatibility and interfacial interaction with EP. Therefore, the tensile, flexural and impact strength of EP/LA@APP6 reached 50.8 MPa, 86.1 MPa and 7.81 kJ/m2, higher than those of pure EP at 48.3 MPa, 81.5 MPa and 7.45 kJ/m2. This flame retardant with simultaneously enhanced fire safety and mechanical properties of epoxy resin was expected to realize the high-level utilization of lignin.

Enhanced flame retardancy and mechanical properties of poly (lactic acid) composites via piperazine pyrophosphate and nanoscale cerium dioxide synergistic flame retarding and uniaxial pre-stretching

The simultaneous improvement of flame retardancy and mechanical properties (including strength, rigidity, and toughness) of PLA was achieved for the first time. A synergistic flame retardant system including PAPP and nano-CeO2 was used to enhance the flame retardant properties of PLA. Especially, uniaxial pre-stretching was further used to improve the mechanical properties of the flame-retardant PLA composites. With the addition of just 1 wt% nano-CeO2, the flame retardant properties of PLA composite were significantly enhanced. Relative to pure PLA, the limiting oxygen index (LOI) of PLA/14 wt%PAPP/1 wt% nano-CeO2 increased from 20.2 % to 28.8 %, achieving a V-0 rating in the UL-94 test. Moreover, the peak heat release rate (PHRR) was reduced from 461KW/m2 to 230KW/m2. Notably, the flame-retardant PLA composites with excellent mechanical properties were achieved using uniaxial pre-stretching for the first time. After pre-stretching, the tensile strength, elongation at break and impact strength of the flame-retardant PLA were significantly increased to 79.82 MPa, 103.8 %, and 9.7 kJ/m2, respectively. This work proposes an ingenious strategy for significantly enhancing both the fire safety and mechanical properties of PLA composites.

Preparation of novel and efficient arylphosphonate flame retardants for simultaneously enhancement of fire safety and UV-shielding properties of transparent thermoplastic polyurethane

Thermoplastic polyurethane (TPU) is highly flammable and UV aging, limiting its application in the field of new energy and electronic device. In this work, a novel macromolecular aromatic phosphonate Bis(4-(((diphenylphosphinyl)oxy)methyl)phenyl)phenylphosphonate (DMP) containing both P-C and P=O was successfully prepared by nucleophilic substitution reaction. The DMP was introduced into the TPU matrix to prepare multifunctional TPU composites. Condensed and gas phase analysis have shown that the flame retardant mechanism of DMP was mainly influenced by flame retardant inhibition and the barrier effect of char layer. Only 5 wt% DMP enabled TPU to obtain the UL-94V-0 rating with the LOI of 27.6 %. Compared with pure TPU, the HRR and THR of TPU/5 wt% DMP were decreased by 19.8 % and 13.2 %. Meanwhile, the matching of the melting point for DMP and the processing temperature for TPU increased its dispersion in TPU matrix. Due to the excellent compatibility between DMP and TPU, TPU/DMP composites almost retained their original transparency and ductility. In addition, TPU/DMP composites exhibited excellent UV resistance, obtaining 100 % UV shielding at UV-B wavelengths and up to 97 % UV isolation at UV-A wavelengths. The study introduced a novel approach for preparing multifunctional flame retardant additives, and opened up wide application prospects for high-performance flame retardant TPU composites in emerging fields such as rail transit and electronic packaging.

Linear polydichlorophosphazene and Ti3C2Tx MXene nanohybrids: Synthesis and application to epoxy resin to improve the fire safety and mechanical properties

Enhancing the fire safety of epoxy resins (EPs) typically requires a significant amount of flame retardants, which often results in considerable degradation of their mechanical properties. To address this issue, a novel flame retardant known as PDCP@DPA@MXene was synthesized and integrated into EP to achieve notable improvements in flame retardancy, smoke suppression, and mechanical strength. By incorporating 1.5 wt% PDCP@DPA@MXene, the impact strength, tensile strength, and elongation at break of the resulting PDM-1.5 %/EP composite reached 12.1 kJ/m2, 57.4 MPa, and 13.0, respectively, reflecting enhancements of 63.5 %, 18.4 %, and 17.1 % compared to the pure EP. The enhancement in tensile strength may be attributed to the high rigidity of Ti3C2Tx MXene, which reinforces the EP matrix. Additionally, the intertwined structure of PDCP@DPA@MXene chains effectively mitigates material fracturing and absorbs impact forces, thus toughening the EP. The presence of phosphorus, nitrogen, and titanate in PDCP@DPA@MXene contributes to the formation of a more compact char layer. The PDM-1.5 %/EP sample achieved a V-0 rating in the vertical UL-94 test and exhibited a high limiting oxygen index of 32.0. Furthermore, the sample containing 2 wt% PDCP@DPA@MXene showed a significant reduction in peak heat release rate (p-HRR) and total heat release (THR), recording values of 689 kW/m2 and 71.9 MJ/m2, which are decreases of 45.1 % and 26.9 %, respectively, compared to pure EP. Additionally, the incorporation of PDCP@DPA@MXene led to a reduction in CO production. These flame-retarded EPs demonstrate strong potential for various applications due to their elevated glass transition temperature and robust thermal stability.

Synergic effect between La-MOF and MXene: Revolutionizing TPU with improved mechanical strength and fire safety

Two-dimensional MXene nanosheets with lamellar structure and high specific surface area are considered promising flame retardants for polymers. However, MXene easily accumulates in polymer materials, resulting in the impairment of their mechanical properties. Metal-organic frameworks (MOFs) not only address this issue effectively but also improve compatibility with polymer materials due to their organic components. In this work, lanthanide rare-earth MOF (La-MOF) were successfully grown in-situ on the MXene surface to prepare hybrid flame retardants (La-MOF@MXene), then added to thermoplastic polyurethane (TPU). The La-MOF suppressed the accumulation of MXene in TPU, and the synergistic effect between them improved the fire safety and mechanical strength of TPU composites. The peak heat release rate of the TPU composites with the addition of 3 wt% La-MOF@MXene was 473.3 kW/m2, which represented a 49.4 % decrease compared to that of pure TPU. Besides, due to the synergic properties of MXene and La-MOF, La-MOF@MXene further reduced total smoke, CO2, and CO of TPU composites in fires. Moreover, with the addition of 3.0 wt% La-MOF@MXene, the tensile strength and elongation at break of TPU composites dramatically improved to 42.4 MPa and 686 %, respectively. Therefore, this study provides a novel paradigm for preparing hybrid flame retardants that can improve the fire safety and mechanical properties of TPU composites, exhibiting broad application prospects.

Synthesis of a novel biomass-based flame retardant featuring vinyl-terminated chemical cross-linking and application in flame retardancy, smoke suppression, toxicity reduction and mechanical enhancement of PAN composite fibers

To develop green and efficient polyacrylonitrile (PAN) fibers with excellent fire safety properties, a new biomass-based flame retardant (PPC@VA) with vinyl-terminated groups was prepared based on the reaction of hexachlorocyclotriphosphonitrile, teat polyphenols, ethylenediamine and vinylphosphonic acid. Subsequently, it was mixed with spinning solution to obtain PPC@VA/PAN through wet spinning, which were then chemically cross-linked via thermal initiation to achieve CC-PPC@VA/PAN fibers. CC-PPC@VA/PAN showed a significant improvement in flame retardancy with a limiting oxygen index value of 32.5 %. The peak of smoke production rate, total smoke production and CO production rate were lowered by 81.9 %, 77.8 % and 91.3 %. Besides, the hazardous gas HCN was greatly suppressed. Owing to the macromolecular entanglement, hydrogen bonding and covalent cross-linking, CC-PPC@VA/PAN improved elongation at break and tensile strength by 19.2 % and 72.1 %. Also, chemical cross-linking contributed to decrease the migration of P/N-based flame retardants, lower the potential risk of water eutrophication and increased the service life of the fibers.

MoS2@Fe3O4 prepared by γ-ray in situ reduction for enhancing the fire safety and mechanical properties of EVA/MCA composites

The high flammability of ethylene vinyl acetate copolymers (EVA) limits its important applications in fire safety, and the addition of highly effective flame retardants can improve this deficiency. Melamine cyanurate (MCA) has limited carbon-forming ability and therefore is often combined with other flame retardants to achieve synergistic flame retardant effects and thus improve the flame retardancy of EVA. Therefore, in this study, MoS2@Fe3O4 hybrid materials were synthesized by in-situ growth of molybdenum disulfide (MoS2) and ferric oxide (Fe3O4) and their structures were characterized using various techniques. The hybrids were blended with melamine cyanurate (MCA) into ethylene vinyl acetate copolymer (EVA) by melt blending method to reduce the fire hazard. The EVA composites with 1.0 wt% MoS2@Fe3O4 blends significantly improved the coke residue and limiting oxygen index values to 22.5 % and 23.2 %, while their peak heat release rate, total heat release, and total smoke release were reduced by 62.5 %, 11.7 %, and 35.3 %, respectively, as compared to pure EVA. The results suggest that the use of MoS2@Fe3O4 hybrids in combination with MCA is a promising strategy for the development of advanced flame-retardant materials.

Statistical analysis of fuel combustion and emissions considering the adverse effects of investment economic environment: Exploring alternatives amid oil prices Swings, digital economy, and local market inflation

The depletion of natural gas reserves, combined with rising oil prices, local market inflation, and concerns about pollution, has accelerated the search for alternative energy sources. As a result, research on turbines and internal combustion engines for electricity generation is increasingly focusing on using vaporized ethanol as a fuel substitute. However, the high cost of analyzing the chemical composition of these fuels often leads to an oversight of their impact on combustion characteristics, such as flame behavior, emission profiles, and temperature distribution.This study employs a statistical approach to assess the combustion and emission characteristics of biofuels, aiming to find suitable alternatives to petroleum-based fuels. By integrating considerations of oil price fluctuations and the digital economy's impact, the research proposes a cost-effective method for evaluating the chemical makeup of vaporized fuels and their effects on post-combustion pollution.Experimental data reveal that alternative fuels can offer stable ignition performance and lower pollution levels, contingent on their specific properties. Fuels with high aromatic content and viscosity tend to produce significant CO emissions, while reducing these characteristics may increase CO2 production. The study also highlights the challenge of simultaneously reducing both CO and NOx emissions. Additionally, the findings show that petroleum gasoline, due to its lower volatility, has favorable fire safety properties and generates fewer pollutants.In the context of economic pressures from rising oil prices and inflation, this research underscores the importance of exploring biofuels as viable, sustainable alternatives for the future energy landscape.

A versatile ionic liquid enables epoxy resin with excellent fire safety and mechanical properties but ultra-low loading

The emergence of ionic liquids provides an effective way to construct new advanced multifunctional epoxy resin (EP) composites with excellent fire retardancy and mechanical properties. In this study, 1-butyl-3-methylimidazolium dibutyl phosphate (BDBP) was synthesized via a facile strategy and then incorporated into the EP matrix. The results showed that ultra-low loading of BDBP (1 wt%) enabled EP composite to achieve a V-0 rating (3.2 mm) in the UL-94 test. When increasing the loading to 4 wt%, the limiting oxygen index (LOI) of EP/BDBP4 composites was improved to 31.9 %. Meanwhile, the peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) significantly decreased by 48.1 %, 21.9 %, and 13.5 %, respectively, compared to neat EP. Moreover, the presence of BDBP increased the tensile strength of EP/BDBP2 by more than 7 %, while all EP/BDBP composites maintained high transparency. In summary, this work provides a feasible and low-cost idea for constructing multifunctional EP composites, paving the way for their applications in aerospace, wind turbines, and electronic and electrical fields.

Rapid preparation of novel hybrid MoS2@Ag@PA with core–shell structure for enhancing fire safety and other critical properties of EVA composites

Rapid preparation of novel hybrid MoS2@Ag@PA with core–shell structure for enhancing fire safety and other critical properties of EVA composites

Nanoconfinement-Enhanced Fire Safety and Mechanical Properties of Polylactic Acid with Nanocerium Metal-Organic Frameworks.

Ce-based metal-organic frameworks (Ce-MOFs) were successfully synthesized by coordinating binary acid and amino structures with cerium oxides. The quantum dot scale endows Ce-MOFs with enhanced modifiability. Additionally, the phosphorus-rich biomass phytic acid, with its numerous hydroxyl groups, strengthens the H-bond network within the system. Ce-MOFs-centered nanoconfinement can form through the multiple H-bond interactions between Ce-MOFs and polylactic acid (PLA) molecules, thereby improving the mechanical and flame-retardant properties of PLA. The PLA/CeCxOy-P-3 composite exhibited excellent fire retardancy and toxic gas suppression, with a 27.8% decrease in the peak heat release rate and a 50% reduction in the peak smoke production rate. Notably, PLA/CeCxOy-P-3 showed an 80% lower peak CO release compared with the pure PLA sample. Moreover, the incorporation of Ce-MOFs positively influenced the tensile properties of PLA, transforming it from brittle to tough. This work designed and synthesized Ce-MOFs on the quantum scale. The resulting Ce-MOFs with the anticipated structure offer a novel direction for preparing MOFs for flame retardant applications.

A new application of MoS2@AG@PA prepared by irradiation: Synergizing with magnesium hydroxide to enhance fire safety and other key properties of EVA composites

AbstractTwo‐dimensional molybdenum disulfide (MoS2) nanosheets are seen as highly promising nanofillers for enhancing polymer properties, yet there is a need for methods that are low‐cost, simple, and environmentally friendly to facilitate the large‐scale production of MoS2 nanosheets. Furthermore, it is necessary to functionalize the MoS2 surface to ensure good interfacial compatibility with the polymer matrix. In this study, MoS2@Ag@PA hybrids were created by generating silver nanoparticles directly on the surface of MoS2 via radiation, followed by encapsulation on the surface of MoS2@Ag through the chelating properties of phytic acid. It is significant to note that, due to the excellent lubrication and physical cross‐linking effects of the MoS2@Ag@PA hybrids, adding one part of MoS2@Ag@PA hybrids can enhance the melt flow rate and elongation at break of the ethylene vinyl acetate copolymer (EVA)/MH composites by 140% and 17.3%, respectively. The simultaneous addition of one part of MoS2@Ag@PA hybrids decreased the peak heat release rate, total heat release, and total smoke release of the EVA composites by 48.7%, 42.7%, and 41.2%, respectively. Moreover, the toxic gasses (e.g., CO) generated by burning EVA composites were significantly reduced compared to pure EVA, indicating improved fire safety. This research not only provides significant opportunities for the green mass production of MoS2 nanosheets but also expands their potential applications in high‐performance nanocomposites.

A bio‐based reactive P/N synergistic flame retardant for improving the fire safety and mechanical properties of epoxy resin

AbstractA high‐efficiency bio‐based P/N synergistic flame retardant (PVFD) is synthesized by combining furfurylamine and vanillin. The compound incorporates two different valence states of phosphorus as flame retardant structures, namely phenylphosphoryl dichloride (PPDC) and 9,10‐dihydro‐9‐oxa‐10‐ phosphophenyl‐10‐oxide (DOPO). PVFD and epoxy resin (EP) can cure into a cross‐linked network, thus not only improving the mechanical properties of EP but also achieving P/N synergistic flame retardant effects. Experimental results demonstrate that EP/PVFD‐5 obtained by adding 5 wt% of PVFD to EP passes the UL‐94 test and achieves V‐0 grade, whose limiting oxygen index (LOI) is up to 38.0%. EP/PVFD‐5 exhibits a decrease of 10.14% in peak heat release rate (PHRR), 16.90% in total heat release (THR), and 10.0% in total smoke release (TSP), while the residual carbon content increases by 8.5%. Additionally, the bending strength, bending modulus, tensile strength, and elongation at break of EP/PVFD‐5 increase by 3.9%, 4.9%, 45.1%, and 26.3%, respectively.Highlights The bio‐based raw materials we used are eco‐friendly and readily available. PVFD, an efficient P‐N synergistic compound, was synthesized. PVFD promotes the char formation of EP and dilutes the O2 concentration. PVFD does not cause the degradation of mechanical properties of EP.

Porous liquids assisted in-situ generated Co-LDH@MOF heterostructure with abundant defects for flame retardant and mechanical enhancement in polyurea composites

Preventing aggregation and inducing homogeneous dispersion of flame retardant nanofillers is critical to enhance the fire safety and mechanical properties of nanocomposites. Although chemical modifications are commonly used to improve the filler’s compatibility with the polymer chain, such methods are often cumbersome and limited. Herein, porous liquids (PLs) with flame retardant function were constructed in which porous defect-Co-LDH@ZIF-67 (d-LDH@ZIF) heterostructure particles were converted into liquid materials by electrostatic interaction with a large-volume solvent. This is also the first report of PLs in the field of flame retardant. Specifically, the d-LDH@ZIF heterostructure was designed by defect engineering and in situ growth strategy to compensate for the low catalytic activity and specific surface area of Co-LDH, and to serve as a rigid porous framework for PLs. Numerous cobalt/oxygen vacancies and lattice defects in the d-LDH@ZIF heterostructure have also been proven to confer higher flame retardancy relative to Co-LDH. d-LDH@ZIF porous liquids (PLs-d-L@Z) presents favorable liquid characteristics and achieves a monodisperse state in the polyurea matrix. The limiting oxygen index of polyurea composites blended with 20 wt% PLs-d-L@Z (3 wt% d-LDH@ZIF content) can be increased to 24.2 % and pass the V-0 rating in the UL-94 test. Moreover, the peak of heat release rate, total heat release, and total smoke production are reduced by around 40.4, 27.0, and 39.9 %, respectively, compared to neat polyurea. Emphatically, the PLs-modified polyurea composites exhibit significantly improved mechanical and impact resistance properties, as well as favorable chemical resistance. This strategy of liquefying solid flame retardant fillers will open an avenue to the design of functional nanomaterials for fire safety and other potential applications.

Ensuring fire safety: compliance tests for the use of polystyrene foam in facades systems

Ensuring fire safety is the most important thing in the construction industry, especially when it comes to facade materials. The inherent flammability of polystyrene foam poses significant safety concerns, especially when integrated into facade systems. Therefore, the main focus is on meeting the strict flammability requirements set for construction products, which are assessed by applying rigorous test procedures. This study focuses on the fire resistance testing of a facade system using EPS 70 with graphite additives. The system has been evaluated according to the strict DIN 4102-20 standards. Tests were conducted under real-world conditions to gain insight into the performance of the EPS 70 in real-world fire scenarios. Temperature measurements were taken at various points in the facade system, including at least 3.5 meters above the combustion chamber. The results showed that the temperature does not exceed 500 °C, so it is possible to quantify the thermal properties of the material and the ability to prevent the vertical spread of fire. After the tests, detailed post-test inspections were carried out to evaluate the internal flame propagation after removing the top layer of plaster. The study confirms that polystyrene foam EPS 70 with graphite additives meets the fire safety requirements of DIN 4102-20, which suggests that it can be used more widely in building facades to improve fire safety in residential and commercial buildings. The study highlights the importance of adhering to installation standards, emphasizing the need for accurate installation practices. It also encourages the development of new composite materials with similar or improved fire safety properties, laying the foundation for further innovations in fire-resistant materials