Search Results (472)

Epoxy resins are widely used in advanced engineering applications, including coatings, adhesives, and electronics. Therefore, improving their flame resistance is important for enhancing fire safety and extending their range of applications. A series of flame retardants based on melamine phosphate derivatives, such as melamine phosphate (MP), melamine dibutyl phosphate, and melamine bis(2-ethylhexyl) phosphate, as well as a zinc borate-modified system (ZnB-MP) has been incorporated into commercially available epoxy resin (Epidian® 601). The blends were characterized using Fourier transform infrared spectroscopy (FTIR) to confirm their chemical structure. Thermal behaviour was investigated using differential scanning calorimetry and thermogravimetry coupled with FTIR gas analysis (TG-FTIR). The flammability performance of the epoxy blends was evaluated using pyrolysis combustion flow calorimetry, which allowed parameters such as heat release rate, total heat release, and heat release capacity to be determined. The incorporation of melamine phosphate-based flame retardants was found to significantly reduce the flammability of epoxy blends, leading to substantial decreases in heat release rate, total heat release, and heat release capacity. The most pronounced effect was observed in systems containing higher concentrations of MP and in cooperative ZnB-MP formulations. Full article

Reliable insulation design for LNG feedthroughs requires fundamental dielectric breakdown data obtained under cryogenic LNG conditions. However, such data remain scarce owing to the explosion-proof requirements imposed by the flammable nature of LNG. Furthermore, the influence of phase differences between LNG and NG on creepage dielectric breakdown behavior along insulation surfaces has received little attention. In this study, an explosion-proof cryostat and test facility compliant with the IEC 60079 series of standards were developed, and dielectric breakdown tests were conducted over a range of electrode gap distances and pressures. Two electrode configurations were employed: rod–plate electrodes for dielectric breakdown characterization in LN₂ and LNG, and creepage electrodes for surface dielectric breakdown evaluation in NG and LNG. Experimental results show that LNG requires approximately 1–2 bar of additional operating pressure above that of LN₂ to achieve equivalent dielectric strength. Moreover, LNG exhibited higher creepage dielectric breakdown voltages than NG under all test conditions, with the difference becoming more pronounced as pressure and creepage distance increased. Post-breakdown surface analysis revealed distinct differences in carbonization patterns between the two media. The findings of this study are expected to serve as fundamental reference data for the insulation design of LNG-based cryogenic feedthroughs. Full article

Ethyl formate (EF) is a promising alternative to methyl bromide for postharvest disinfestation, but berry export chains require efficacy under refrigerated handling without loss of marketable quality. Using spotted-wing drosophila (Drosophila suzukii) in blueberries as a cold-chain model, we compared stage-specific tolerance at 5 to 15 °C and identified 1-day-old eggs as the most tolerant stage, with mortality strongly temperature dependent. Egg-stage concentration to mortality relationships were quantified under 4 h exposures at 5, 10, and 15 °C to nominate temperature-specific intensities within EF flammability safety limits. Candidate schedules (69, 83, and 94 mg·L⁻¹ for 4 h at 5, 10, and 15 °C) were confirmed by verification-scale zero-survivor tests under simulated cold-chain conditions, achieving complete control of the most tolerant egg stage. Post-treatment quality was assessed after 1, 7, and 14 days of cold storage. Weight loss, firmness, total soluble solids, titratable acidity, sucrose, and proanthocyanidins were driven mainly by storage time and temperature. EF effects were limited to transiently elevated respiration early in storage, with no detectable injury, decay, or adverse changes in appearance or other physicochemical attributes. Overall, EF provides a cold-chain compatible processing window integrating efficacy, operational safety, and quality preservation for refrigerated blueberry export logistics. Full article

Germicidal UV (GUV) technology, which utilizes light in the UV-C portion of the electromagnetic spectrum, has become a viable alternative to traditional chemical disinfectants to sanitize surfaces in the built environment. However, the degradation of polymers that have been exposed to UV-C light is a concern due to the potential change in structural integrity and visual appearance. The resistance to UV-C degradation is often tabulated in relative qualitative terms, making it rather difficult for designers to understand the implications of the choice of a material of construction. This study was initiated to develop a systematic, standardized method of exposing polymeric materials to UV-C light to ensure that the subsequent property measurements can be compared quantitatively. The exposure method is based on an apparatus that can be readily duplicated using commercially available materials and equipment. To demonstrate the proposed exposure framework, samples of six formulated polymer resins were exposed to three UV-C light sources with different peak wavelengths (KrCl excimer lamp [222 nm], low-pressure mercury lamp [254 nm], and LED lamp [280 nm]). Exposures were conducted at five independent laboratories, and subsequent property testing was performed at multiple facilities using established materials-characterization methods. This coordinated approach enables comparative evaluation of material responses across UV-C source types, wavelengths, and dose levels, providing a practical foundation for developing standardized exposure methodologies and informing future formulation development efforts. Post-exposure testing included quantifying changes in optical, mechanical, and physical properties, including color, gloss, reflectivity, spectral transmittance (haze), flammability, tensile strength, and elastic modulus. These measurements were conducted using established laboratory methods commonly employed throughout the polymer and materials industries. Together, these results provide a comparative dataset illustrating how polymer properties respond to coordinated UV-C exposure conditions, supporting the development of standardized approaches for evaluating material durability in germicidal UV applications. Full article

Lithium-ion batteries (LIBs) release significant amounts of toxic, corrosive, and flammable gases when they enter thermal runaway (TR). These emissions can be hazardous to human health, damage nearby equipment, pose fire and explosion risks, and degrade air quality. This study measured concentrations for a range of hazardous gases released from TR-driven combustion of cylindrical lithium iron phosphate (LFP) and pouch-style lithium cobalt oxide (LCO) LIB cells. Gas emissions were measured by dedicated analyzers and Fourier transform infrared spectroscopic (FTIR) analysis, and emission factors were calculated. Dangerous concentrations of hydrogen fluoride (HF) were observed, reaching up to 50 ppm from the combustion of single LIB cells. Large amounts of combustible electrolyte solvents and light hydrocarbons were released in some cases, depending on cell combustion behavior. Electrolyte solvents, hydrogen chloride (HCl), and particles were released earlier than other species and should be targeted for early TR detection. Gas emissions were correlated with cell state of charge (SOC) and combustion behavior. Cells at high SOCs had higher peak concentrations of HF, HCl, CO, and flammable hydrocarbons, and these peaks happened sooner after cell failure than for low-SOC tests. Full article

More than 95% of building materials in Europe are produced from fossil raw materials. Over the past two decades, numerous scientific studies have demonstrated that building materials made from agricultural plants or industrial processing waste can compete with traditional materials. In this work, engineered wood composites were prepared from biopolyurethane and barley straw, and their properties were evaluated. Barley straw from bales was milled through sieves of different sizes. Four straw fractions of 5, 10, 25 and 35 mm were prepared for testing. During the research, the granulometric composition, particle density and shape of various fractions were evaluated. Engineered wood composites were prepared using different filler fractions and a biopolyurethane binder. In this study, engineered wood samples were produced using biopolyurethane binders at straw-to-binder ratios of 0.5 to 1.5. Different pressure levels were used for sample preparation: 1.5, 2.25 and 3.0 MPa. This study evaluated the influence of the granulometric composition and particle shape of straw on the properties of engineered wood composites. Tests showed that the highest compressive strength, 17.0 MPa, was achieved with composites formed from a 5 mm straw fraction, which had the highest density. The samples with the highest density were also characterised by the lowest swelling (5–10%) and water absorption (1–2%). The flammability of the samples showed that at a 0.5 binder/straw ratio, the composite was non-combustible and did not support flame spread after the flame source was removed. Full article

Given the increasing frequency, severity, and socioecological impacts of wildfires, there is an urgent need for robust frameworks to better characterize fire behavior and flammability patterns across ecosystems to support early warning, mitigation, and management strategies. However, flammability remains difficult to quantify and scale, as it involves multiple interacting components that are typically measured at the bench scale. This study aimed to establish empirical links between spectral information, plant traits, and flammability metrics, and to scale these relationships to satellite imagery to translate these metrics into a spatial context. We combined laboratory spectroscopy, plant trait measurements including leaf mass per area, carbon, and cellulose, and combustion experiments using a simple and reproducible burning device. In total, 84 samples were collected and analysed, allowing us to characterise how spectral signatures relate to vegetation traits and fire behaviour. Spectral indices were developed to estimate plant traits, which were subsequently used as predictors in flammability models. These models were then transferred to Environmental Mapping and Analysis Program (EnMAP) hyperspectral imagery to derive spatial estimates across eucalypt forests and grasslands of the Australian Capital Territory (ACT). Spectral information distinguished fuel types and captured variability of the plant traits, while these traits showed associations with combustion behaviour. Based on these links, the best-performing model predicted the rate of temperature increase, a combustibility metric, in eucalypt forests (R² = 0.70; Root Mean Square Error = 32.48 °C/s). In contrast, grassland models showed limited predictive performance, likely due to weaker relationships between plant traits and flammability metrics. Overall, this study demonstrates a practical and scalable approach for deriving flammability maps from hyperspectral and in situ data, highlighting the potential of plant-trait-based remote sensing. The resulting maps should not be interpreted as standalone fire risk products, but rather as a characterization of the structural and biochemical drivers of flammability. The main constraint of this work is the limited sample size. Future research should expand spatial and temporal coverage to better capture vegetation variability and enable the inclusion of independent validation datasets. Exploring alternative combustion protocols and testing more advanced spectral modelling approaches for trait estimation would provide additional insights. Full article

Polyurethane (PU) is a highly versatile class of polymer utilised in many industries, including the aerospace sector. In conjunction with its superior mechanical properties, chemical resistance, and durability, it can be highly flammable depending on its form. This poses a risk aboard aircraft, which contain numerous fire hazards and cramped cabin spaces, proving an obstacle for the evacuation of passengers in an emergency. Flame-retardant additives have proven to enhance the thermal properties of polyurethane, but their toxicity and tendency to degrade mechanical performance make them unappealing. This review addresses three main topics: (1) the basic synthesis and structure of PU and modification through additives; (2) types of PU, their properties, and applications in the aerospace industry; and (3) evaluation methodologies for characterising PU performance, studying mechanical properties and thermal degradation. Several key challenges remain, including understanding the long-term durability of modified PU, optimising between fire performance and mechanical properties, improving the sustainability of PU throughout its lifetime, and validating numerical simulation as a viable testing method. This review aims to guide future research on modified PU technology to achieve safer, high-performing, and sustainable solutions for the aerospace industry and beyond. Full article

In this work, poly(acrylic acid)-based layers were injected to form a sandwich layer between the cationic and anionic species for a compact and effective fire-retardant coating on cotton fabric using the layer-by-layer coating technique. From the SEM analysis, as the number of tri-layers increases, the attachment intensity increases, as can be seen for poly(acrylic acid) chitosan and bentonite clay PCB-5TL (the highest tri-layers), while in the case of halloysite-based coatings, as the number of tri-layers increases, instead of attachment, the agglomeration increases due to the high surface area of halloysite nanoclay tubes. FTIR and UV confirmed the finding from the new peak entry and an increase in thickness. The highest thermal residue, ~18%, was obtained for poly(acrylic acid) chitosan and halloysite nanoclay PCH-5TL with a maximum degradation peak intensity at ~389 °C. From the flammability and after-burning SEM investigation test, it was observed that the halloysite-based coating with a higher number of layers offered higher resistance against the flame spread and ignition and, thus, produced a higher amount of char. Full article

The building-integrated photovoltaic (BIPV) system has advantages in construction and energy, but due to the use of flammable polymer packaging materials, it introduces complex fire safety-related challenges. Although polymer backboards are traditionally considered to be the main combustible components in photovoltaic modules, recent studies have shown that ethylene–vinyl acetate (EVA) packaging materials play a key role in the development of fires. This study investigated the fire behavior, optical properties and system-level fire effects of montmorillonite (MMT) nano-clay-modified EVA packaging materials. Through the 50 kW/m² conical calorimeter test, optical transmittance measurement and the accelerated aging test, pure EVA and EVA containing 3% MMT were evaluated, and the measured fire parameters were further incorporated into the simplified BIPV cavity fire model. The results show that MMT modification reduces the peak heat release rate of EVA by about 30%, delays the ignition time, and increases the formation of carbides, while maintaining the optical transmittance of more than 88%. At the system level, the reduction in heat release leads to a decrease in the cavity temperature and delays the ignition of adjacent insulation materials. These findings establish a direct link between material-level fire behavior and the fire performance of BIPV systems, indicating that nano-clay-modified EVA is a feasible strategy that can improve the fire safety of BIPV systems integrated into the facade without compromising optical or durability requirements. Full article

Against the backdrop of the global transition toward clean and low-carbon energy systems, hydrogen has emerged as a promising alternative to fossil fuels owing to its carbon-free characteristics and broad cross-sector applicability. However, the high diffusivity and wide flammability range of hydrogen pose significant safety challenges for its large-scale deployment. Conventional detection methods are generally limited to point-based data acquisition and struggle to capture the transient flow-field characteristics associated with hydrogen diffusion as well as combustion or explosion processes. This review aims to systematically clarify the exclusive technical advantages of schlieren visualization technology for hydrogen research, summarize its application progress in hydrogen and hydrogen mixture diffusion distribution and combustion/explosion flow-field testing, and propose future optimization directions and application expansion paths. Schlieren visualization, based on optical refraction principles, has evolved from a traditional experimental technique into a comprehensive system adapted to diverse scenarios, including high-speed schlieren, Z-type schlieren, background-oriented schlieren (BOS), and color schlieren. Owing to its non-intrusive nature, high spatiotemporal resolution and full-field visualization capability, schlieren technology can directly observe the fundamental diffusion behavior of hydrogen jets and capture distinctive flow features throughout all stages of hydrogen mixture combustion and explosion. It effectively overcomes the limitations of conventional detection methods and has become an indispensable tool in hydrogen energy safety research. Future research should focus on improving technical performance, strengthening interdisciplinary integration with machine learning and digital twin technologies, and expanding application scenarios to multi-field coupling systems, so as to support the safe and efficient development of the hydrogen industry and contribute to global carbon peaking and carbon neutrality goals. Full article

Rotary kiln-based activated carbon production combines high-temperature operation with flammable/reducing gases, carbonaceous dust, and downstream off-gas treatment and acid/base washing, creating complex escalation pathways. This study prioritizes safety improvements by applying classical failure modes and effects analysis (FMEA) and a transparent Fuzzy-FMEA framework to 18 representative failure modes (six each for kiln/activation, acid/base handling, and atmosphere/control). Five experts evaluated Severity, Occurrence, and Detection on a 10-point scale. The fuzzy model used triangular membership functions (L/M/H), a monotonic 27-rule base, Mamdani max–min inference, and centroid defuzzification to compute a continuous fuzzy risk priority number (FRPN, 0–10). Classical FMEA identified dust explosion (RPN = 405), temperature control failure (RPN = 378), and off-gas leakage (RPN = 324) as the highest-ranked risks. Fuzzy-FMEA preserved the top-risk group while more strongly highlighting barrier-related risks, placing off-gas leakage, instrumentation/interlock failure, and electrostatic ignition control alongside dust explosion (FRPN 9.221–9.332). The rankings were strongly correlated (Spearman ρ = 0.871; Kendall τ = 0.752), yet mid-risk items were rearranged (mean |Δrank| = 2.06; max = 5), improving discrimination within tied RPN clusters. The five highest-priority scenarios were reconstructed into actionable engineering packages, including dust and ignition control, off-gas integrity linked to shutdown logic, interlock proof testing and bypass management, and independent protection layers for kiln temperature control. Full article

This work focused on the investigation of sulfonated lignin as a novel and sustainable reinforcing filler for polyamide 6 (PA6) composites. Different formulations were thus prepared by melt compounding, varying the lignin content (5, 10, and 20 wt%). The interaction between lignin and PA6 was systematically studied through rheological, structural, morphological, thermo-mechanical, and flammability tests. Rheological measurements showed an increase in the complex viscosity and viscoelastic moduli with increasing lignin content, suggesting restricted polymer chain mobility and the formation of strong physical interactions between the molten PA6 and the lignin particles. Microstructural observations through FESEM highlighted a good dispersion of lignin particles and efficient filler–matrix interfacial adhesion. Moreover, the addition of lignin significantly increased the tensile stiffness of the composites (up to 3.4 GPa), and a lignin content of 10 wt% enhanced the tensile strength up to 58.4 MPa (i.e., +45% compared to neat PA6) without compromising the ductility. Finally, UL-94 tests revealed an improvement in flame retardancy at higher lignin contents due to the intrinsic char-forming ability of this filler. These results demonstrated that lignin could be an effective multifunctional bio-based filler that can improve the thermo-mechanical performance of PA6 without the need for compatibilizing agents. Full article

Cotton fabrics are widely used in textiles due to their comfort and breathability, but their high flammability (limiting oxygen index (LOI) ≤ 18%) poses serious safety risks. While conventional flame-retardant treatments often rely on synthetic chemicals or toxic additives, biobased alternatives remain underdeveloped. The flame resistance of cotton fabrics may be enhanced using multilayer biocoatings of chitosan and sodium alginate applied via layer-by-layer (LBL) assembly—a sustainable and scalable approach. Cotton samples were coated with chitosan and sodium alginate bilayers (1, 2, 5, and 10 layers) using the LBL method. Flame resistance was evaluated using vertical flame tests and limiting oxygen index (LOI) testing according to ASTM D2863-09. The sample coated with 10 bilayers significantly outperformed uncoated cotton and lower-layer samples. With a char length of 9.72 cm (68% reduction), no dripping was observed in the vertical flame tests, and the LOI value was 23.47% compared to uncoated cotton (LOI = 18.04%). These improvements were attributed to the formation of a cohesive and protective carbon layer, which is likely capable of inhibiting the formation of flammable gases. Biomaterial multilayer coatings made from biomaterials, such as chitosan and sodium alginate, represent a promising and environmentally friendly alternative to traditional methods in improving cotton’s flame resistance. The development of this technology points to potential applications in protective textiles and industrial safety clothing. Notably, chitosan and sodium alginate coatings are biocompatible. The term “biomaterials” refers to materials intended for interaction with biological systems, particularly for biomedical-related applications. The term “biobased materials” is used exclusively to describe materials derived from renewable biological sources. Full article

To protect the environment, the R1234yf refrigerant was introduced into the air conditioning systems of modern vehicles. Its price is much higher than that of previous refrigerants, and the gas is slightly flammable, making the prompt detection and repair of even small leaks even more critical. This research aimed to develop a simple, dashboard-based method for serially monitoring and visualizing anomalies in cars after production and before and shortly after delivery. It is possible to infer the presence of minor leaks through online or frequent pressure monitoring after the system has been “resting” (last ignition off for at least 5 h to allow system stabilization: air conditioner vs. outer or engine coolant temperature). Using this method, it can be determined whether the given pressure losses fall within the normal operating range. The essence of the technique is to detect a possible small amount of leakage by monitoring the pressure change (Δp) of the air conditioning system, supported by dashboard(s). The results on the test fleet with 500 cars show that the procedure can be suitable for detecting defects that cause micro-leaks immediately after production. The false-negative detection rate was 0.2, and the false-positive rate was 1.2 at a threshold of ±0.5 bar. Based on a practical example, the method can also be applied to offline cars until the first factory-related claim occurs. Full article