Fire Retardant Performance Research Articles

Investigating the Effect of Blend Composition on the Burning Rate of PTT/PP and PTT/LLDPE Blends and Mechanism Thereof

The present manuscript focuses on assessing the fire retardant performance of Polytrimethylene Terephthalate (PTT) polymer blended with varying proportions of Polypropylene (PP) and Linear low-density polyethylene (LLDPE), separately. The fire retardancy behavior is studied using Fourier transform infrared spectroscopy (FTIR) and the structure of the blends observed by Scanning electron microscope (SEM). The blend composition plays a vital role on the burning rate, and therefore the fire retardancy, of PTT polymer after blending. In both the blend systems, an increase in the addition of PP or LLDPE lowers the burning rate for 10-15 wt.% of addition. The burning rate increases with further addition due to the fact that pure LLDPE and PP burns faster than pure PTT. The PTT/PP and PTT/LLDPE blends under present study proves to be cost effective than pure PTT, all the while exhibiting similar burning rate characteristics, making them suitable for a wide range of applications where both cost efficiency and fire resistance are essential. The FTIR and SEM analysis provides insight into the chemical changes occurring during the thermal degradation of the blends, thereby supporting to understand the fire-resistant mechanism of the blends.

MXene assisted simple recycle of waste cellulose fiber with alginate fiber into fireproof and electromagnetic interference shielding composite

Textile wastes rapidly grow into a challenge when a significant portion of them are processed by landfilling or incineration, leading to hazardous solid and volatile pollutants. This work investigated the utilization of wasted cellulose fiber by recycling it with calcium alginate fiber into a fireproof composite filler as a circular economy strategy, followed by the modification with MXene dispersion to further enhance its fire resistance and offer it the electromagnetic interference shielding ability. A comprehensive investigation elucidated the flame retardant mechanism of the composite felt via studying its combustion behavior, the microstructural morphology of residue char, and the gasous compounds produced. The results indicated that this composite felt generated a large number of nonflammable gas species and fibrous residue char, serving as a natural barrier to impede the fuel supply and suppress heat diffusion, thereby endowing the composite felt with an outstanding fire retardant performance and reduced carbon footprint. Compared to other textile waste recycling processes, the opening-carding-needling punch technique employed in this study was more energy-efficient and environmentally friendly. The recycling of waste cellulose fiber into functional fireproof composites not only extended the practical applications of waste resources but also mitigated the negative environmental impact of textile disposal.

Improving the fire-retardant performance of industrial reactive coatings for steel building structures

The main aim of this study was to determine key factors that regulate fire-retardant effectiveness of intumescent coatings comprising of ammonium polyphosphate, melamine, pentaerythritol, polymer binder. Fulfillment of the research objectives resulted in the development of a coating with R120 fire resistance. The expected service life of the coating is at least 15 years when applied at Z2 type of environmental conditions (indoor use). It was established that in order to provide fire resistance of around R30 it is advisable to use the styrene-acrylic polymers as binders for both water-based and organic-based intumescent systems. The ratio of target components ammonium polyphosphate/melamine/pentaerythritol in such systems should be close to 2/1/1. The coating thickness is to be 0.4–0.5 mm. To achieve higher fire resistance (R60 or more) the coating should include a vinyl acetate derivative as a binder (copolymers with ethylene or vinylversatate). Target components ratio in this case is to be close to 3.5/1/1.5, while the coating thickness should be kept at 1.6–1.8 mm. If the required class of fire resistance is above R120, coating thickness is usually to be kept above 3.5 mm. In order to achieve higher fire resistance, it is advisable to use nano-clay additives and reinforcing fibers in intumescent compositions.The obtained results were used in the development of intumescent coating, which is produced industrially and provides over R120 fire resistance of steel, which was confirmed in standardized full-scale fire tests.

Transforming environmental sustainability: Lime‐treated used coffee grounds for innovative eco‐friendly epoxy composite materials

AbstractThis study proposes an innovative method to recycle used coffee grounds into environmentally friendly epoxy composite materials while emphasizing the sustainability of this process. This approach focuses on using lime‐treated coffee grounds as a reinforcing agent for epoxy composites. Diverse analytical techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and mechanical testing according to international standards have been used to evaluate the properties of materials. Coffee grounds have been treated by soaking in Ca(OH)2 solution with different concentrations (0.1 m, 0.3 m) and processing times (1, 3 and 5 days), then combined with epoxy resin to form composite materials. The results showed that using coffee grounds treated with Ca(OH)2 significantly improved the stability and performance of epoxy composites. The best fire retardant performance was achieved with a Ca(OH)2 solution with a concentration of 0.3 m and a treatment time of 3 days, with a limiting oxidation index (LOI) of 21.6%. Furthermore, the compressive strength increased by about 20.79% compared to pure epoxy resin. This study highlights the potential of optimizing coffee grounds treatment parameters with Ca(OH)2 to improve the properties and performance of epoxy composites, thereby promoting practical application and environmental protection.

Ultrastable superhydrophobic melamine sponge via a one-step aqueous solution-based approach for oil/water separation

In this study, an eco-friendly aqueous solution-dipping method was developed for the synthesis of an ultrastable superhydrophobic melamine sponge (MS). The MS exhibits not only a high oil adsorption capacity of 46.3–149.5 times of its own weight, but also a good reusability with a slight decrease in adsorption capacity after 20 absorption-desorption cycles. Moreover, the continuous separation of immiscible oils/organic solvents and water with vacuum assistance is also realized. Besides, the material also features with exceptional physicochemical stability and fire-retardant performance, enabling its potential applications in extreme environments (high temperature, strong wind and waves, strong acids and alkalis, UV radiation, etc.). The as-established synthesis pathway has its chance in simplifying the industrial fabrication processes of composited functional sponges.

Surface decoration of flexible Si3N4 nanowire membrane by hydroxyapatite micron-flake with excellent thermal insulation at 1300 °C

Flexible and excellent thermal insulation membranes are required as the thermal protection system materials of aerospace vehicles for next-generation space missions. Using ceramic membranes with ultralow thermal conductivity has been proved to be an effective way to protect the electronic components inside the fuselage. Herein, we decorate hydroxyapatite (HA) micron-flake onto Si3N4 nanowire membrane (SR), and investigate the thermal stability, fire-resistance and thermal insulating properties of the obtained SR decorated by HA micron-flake (SRHM). Surface decoration of HA micron-flake onto the SR results in the formation of well-interconnected junctions and the increase of interfacial thermal resistance. Due to the increased interfacial thermal resistance, the as-prepared SRHM exhibits good thermal insulation and outstanding fire-retardant performance. SRHM shows robust mechanical property with tensile strength value of 4.10 MPa, increased by 247.5% compared to the SR without the surface decoration by HA micron-flake. The thermal conductivity of SRHM is as low as 0.037 W m−1 K−1, reduced by 33.9% compared to the SR without the surface decoration by HA micron-flake. After SRHM is heated by a butane blow torch at 1300 °C for 30 min, no obvious change is observed in the macroscopic morphology. And the temperature of the backside for SRHM maintains at a stable temperature of ∼260 °C for 300 s, which is 1040 °C lower than that of the front side. Additionally, SRHM can protect the electronic components form being burnt under the heating of an alcohol lamp for 30 min. The successful preparation of such thermal insulating and fire-retardant SRHM will open up a new world for the widespread applications of ceramic membranes in the fields of aerospace vehicles.

Highly tough and flame retardant polystyrene composites by elastomeric nanofibers and hexagonal boron nitride

Thermoplastics flammability remains a considerable threat during fire incidents. Conventionally, halogen-free fire retardant (FR) additives are incorporated into thermoplastics to reduce fire hazards. However, the incorporation of FR additives compromises the mechanical properties (most notably, toughness) of thermoplastics, which has impeded the development of thermoplastic products that possess both high mechanical and fire retarding performances. This study reports an in situ nano-fibrillation strategy to fabricate thermoplastics that exhibit fire retarding properties and a combination of high stiffness and toughness. The proposed composites were composed of in situ thermoplastic polyester elastomer (SBC) nanofibers within a polystyrene (PS) matrix containing hexagonal boron nitride (hBN) as the FR additive. The presence of elastomeric nanofibers successfully mitigated the losses in mechanical performances caused by the incorporation of 2 wt% hBN. Specifically, the inclusion of 15 wt% SBC nanofibers significantly enhanced the toughness of the PS-hBN composite by 350% with negligible effects on the stiffness as compared to neat PS. Furthermore, the presence of nanofibers resulted in synergies with hBN to fabricate composites with enhanced fire retarding performance since the total heat release (THR) of PS-hBN composite decreased from 212 to 189 MJ m−2 with 10 wt% nanofibers. Thus, nanofibers behave as a multifunctional component that compensated for the losses in mechanical performances caused by hBN incorporation, while enhancing the fire retarding performance. This strategy can be effectively implemented to fabricate the next generation of polymer composites with high fire retarding and mechanical properties for various applications including energy storage packs for batteries and electronics.

A sustainable pore wall strengthening for strong and fire-retardant nanopolymerised wood

Cellulose aerogels prepared by the directional freezing method show huge potential in the field of thermal insulation materials, tissue engineering, and building blocks. However, poor mechanical strength and fire resistance limit their application in buildings and engineering. Inspired by the chemical crosslinking of wood cell walls, we propose a sustainable wall-strengthening strategy for robust cellulose aerogels with high mechanical strength, superior thermal insulation, and flame-retardant performance, denoted as nanopolymerised wood. Specifically, oriented cellulose aerogel, prepared from cellulose nanofibers and polyvinyl alcohol, is impregnated with Na2SiO3 solution and then thermally crosslinked to obtain nanopolymerised wood. The cellulose nanofibers served as a supporting skeleton, while polyvinyl alcohol and Na2SiO3 acted as fillers and adhesives, respectively. This combination densifies the pore walls, resulting in an enhanced compressive strength of the nanopolymerised wood to 64.2 MPa. The directional channels with high interfacial thermal resistance lead to a low radial thermal conductivity of 0.027 W·m−1·K−1. Furthermore, the covalently crosslinked silicates provide nanopolymerised wood with outstanding fire-retardant and self-extinguished properties. The biodegradable components, good mechanical properties, superior thermal insulation, and fire-retardant performance of nanopolymerised wood make it a promising material for sustainable buildings and machine envelopes.

Halogen-Free Waterborne Polymeric Hybrid Coatings for Improved Fire Retardancy of Textiles.

Wildfires are becoming more intense and more frequent, ravaging the habitations and ecosystems in their path. One solution to reducing the risk of damage to buildings and other structures during a fire event is the use of fire-retardant coatings that can stop or slow down the spread of flames, especially for textile materials. The present study focuses on the preparation and application of halogen-free boron/bentonite-based polymeric fire-retardant (FR) hybrid coating formulations for fabrics such as cotton (CO) and polyester (PE) fibers. For the preparation of FR composites, two types of boron derivatives, disodium octaborate and zinc borate, were used in combination with sodium bentonite. A styrene-acrylic copolymer was specifically synthesized and used as a coating binder for FR components to apply on fabrics. The properties of the synthesized copolymer and FR composites were characterized with a particle size analysis, FTIR spectroscopy, a dynamic mechanical thermal analysis (DMTA), and rheological measurements. The obtained hybrid composites based on styrene-acrylic copolymers and two different inorganic fillers were applied on cotton (CO) and polyester (PE) fabrics with a screen-printing technique, and the flame retardancy performance of the finished textile samples was investigated by means of flame spread and limit oxygen index (LOI) tests. The findings showed that the FR-composite-coated fabrics had higher LOI values and much decreased flame spread rates in comparison with uncoated ones. Among the boron derivatives, the composites prepared with disodium octaborate (FR-A) had much more pronounced LOI values and decreased flame spread behavior in comparison with the composite with zinc borate (FR-B). When compared to a commercial product, the FR-A composite, in conjunction with the specially synthesized polymer, demonstrated commendable fire retardancy performance and emerged as a promising candidate for a halogen-free waterborne fire-retardant coating for fabrics.

An Experimental Study for Deriving Fire Risk Evaluation Factors for Cables in Utility Tunnels

In this study, we performed three tests to measure the fire-retardant performance of power cables installed in utility tunnels. The standards we applied for testing are ISO 5660-1, NES 713, and IEEE 1202. Specifically, we performed a cone calorimetric analysis, calculated the toxicity index, and measured the flame spread length on material surfaces. Even though the same fire-retardant chemical composites were applied, various differences in fire-retardant performance were found depending on the chemical properties of the cable sheath and insulation. We also found that gaseous substances generated during the burning of cables can serve as important risk assessment factors in fires. We determined that, in addition to the heat generated when the cable burns, the toxic gases emitted at this time can also be a risk factor. This is because it is important to consider any potential risk to a person entering as part of an initial response to an event or accident involving cables installed in utility tunnels. Moreover, in the event of a fire in the cable, there is a risk of hazardous substances flowing into the city center as toxic gases are released. Therefore, we determined that the risk of hazardous gases emitted during cable fire should be reflected in the fire-retardant performance standard.

Improvement in Monterey pine of the flame retardancy, thermal conductivity, and mechanical performance through incorporating functional epoxy resin

AbstractMonterey pine is a renewable biomass resources with structural and chemical characteristics, but is limited by its flammability, poor mechanical properties, and subpar thermal conductivity (TC). Herein, a thermal conductive and flame retardant the multifunction epoxy resin (MEP) prepolymer was injected into the Monterey pine and subsequently cured. The results showed that impregnated MEP Monterey pine, maintained its original cellular structure under applied loads compared to pristine Monterey pine, thus, giving the composite wood better mechanical integrity than its neat counterpart, which served as thermally conductive pathways within the composites. The TC was measured to be 0.12 Wm−1 K−1 for pristine Monterey pine. Whereas, the infiltrated MEP/wood composite yielded a TC of 0.94 Wm−1 K−1 which correlates to a 683.3% enhancement. Besides, the tensile strength of the prepared composites in the longitudinal and radial directions were observed to be 75.0 and 21.7 MPa, and increased by 63.4% and 152.3% compared to that of pristine Monterey pine, respectively. Combustion tests revealed that the Monterey pine/MEP composites self‐extinguished after ignition and departing from the flame source while the pristine Monterey pine did not. It was deduced that the TC, fire retardancy, and mechanical performance of Monterey pine were simultaneously improved by injecting the multifunctional epoxy resin prepolymer, which provide a wide application potential in heat dissipation furniture field.Highlights The multifunction epoxy enhanced the multiple performance of Monterey pine. The wood composite yielded a high thermal conductivity. Monterey pine/MEP composites managed to self‐extinguish after ignition.

Phosphorous-containing flame retardant plasticizer based on Cassia fistula seed oil and their application in poly(vinyl chloride) films

The need for safety and sustainability has prompted the development of flame-retardant bio-based plasticizers from renewable resources. In this study, an efficient phosphorous-containing flame retardant plasticizer (ECFSO-P) for poly(vinyl chloride) (PVC) was synthesized using Cassia fistula seed oil and characterized by fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and proton nuclear magnetic resonance (1H NMR) spectroscopies. In replace of the dioctyl phthalate (DOP), the ECFSO-P was employed as a flame retardant plasticizer to produce poly(vinyl chloride) (PVC) blends. The PVC blends were prepared using ECFSO-P, DOP, and ECFSO-P + DOP blends as plasticizers. The PVC blends with different concentrations of DOP and ECFSO-P were investigated with thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical properties, fire retardant performance, crystallinity, leaching, volatility, and density functional theory (DFT) studies. The TGA results showed that the thermal degradation temperature of PVC blends plasticized with ECFSO-P reached 230.6 ºC. The glass transition temperature, Tg decreased to 34ºC as determined by DSC, when DOP was completely replaced with ECFSO-P. When PVC was plasticized with ECFSO-P only, the tensile strength and elongation at break reached 6.41 and 508.83, respectively. The leaching and volatility properties of ECFSO-P plasticized PVC blends were better than DOP plasticized film. Limited oxygen index (LOI) and smoke density rating (SDR) values were increased by 6.7% and 17.4%, respectively. The WAXS profiles showed that ECFSO-P did not alter the order of crystallinity among the PVC chains. As expected, the hydrogen bonding interactions between plasticizers and the -CH-Cl units of PVC were confirmed by DFT calculations.

A P/N-containing hardener endowing bio-based epoxy thermosets with excellent thermal, mechanical and intrinsically flame-retardant performances

In view of the drawbacks of severe dependence on petroleum resources and flammability of commercial epoxy thermosets, a novel intrinsically flame-retardant bio-based epoxy resin was manufactured through the curing reaction between the synthesized cardanol-derived epoxy monomer (CFEP) and a DOPO-based curing agent (DPDM). In addition, CFEP and DGEBA thermosets cured by DDM were used as the contrast samples. The TGA results showed that CFEP-DPDM possessed significantly enhanced thermal stability with higher char residues of 10.3 % and 17.8 % at 700 °C for air and N2 atmospheres, respectively, which were higher than those of both DGEBA-DDM (0.76 % and 12.4 %) and CFEP-DDM (3.4 % and 12.2 %). The Tg of CFEP-DPDM was 162.0 ℃ which was obviously higher than that of neat CFEP-DDM (95.2 ℃) and comparable to that of commercial DGEBA-DDM (154.1 ℃) under DMA test, and DSC test presented similar trend of Tg results. Moreover, CFEP-DPDM possessed the highest crosslinking density (νe), indicating excellent mechanical property, which was further verified by tensile analysis that the tensile strength (44.6 MPa) and tensile modulus (3.2 GPa) of CFEP-DPDM was comparable to commercial DGEBA-DDM. As for the fire-retardant performance, CFEP thermoset cured with DPDM exhibited a high LOI value of 33.5 % and passed UL-94 V0 rating. Furthermore, compared to those of CFEP-DDM, the PHRR, THR, CO2P and FIGRA of CFEP-DPDM were declined by 41.0 %, 37.6 %, 60.0 % and 39.8 %, respectively. Ultimately, the flame-retardant mechanism of CFEP-DPDM was investigated by further condensed and gas phases analyses. In brief, the synthesized bio-based epoxy thermosets with excellent comprehensive performance displaying high promise for application.

Influence of boron bearing fillers on flame retardancy properties of huntite hydromagnesite filled ductile PLA biocomposites

In this work, the flame retardant influences of colemanite and boron oxide are investigated in huntite-hydromagnesite (HH) containing plasticized poly (lactic acid) (PLA) biocomposites. The composites are characterized using limiting oxygen index (LOI), horizontal (UL 94 HB) and vertical (UL-94 V) burning tests, mass loss calorimeter and thermo gravimetric analysis (TGA). The addition of colemanite causes enhanced fire retardant performance with higher UL-94 V rating and LOI value and lower pHRR value. V0 rating and the highest LOI value is observed with the addition 1 wt % colemanite. When the concentration of colemanite reaches to 3 and 5 wt %, the samples get V1 rating. When the concentration of colemanite reaches to 5 wt %, pHRR and avHRR values are lower than those of the reference sample. The addition of boron oxide caused only improvement in LOI value. The highest LOI value (33.2) is observed in 5 and 10 wt % boron oxide containing samples.

Development of ductile green flame retardant poly(lactic acid) composites using hydromagnesite&huntite and bio‐based plasticizer

AbstractTurning brittle poly(lactic acid) (PLA) to ductile form via plasticizer inclusion is an effective option in the case of processing with high amounts of additives. Additionally, the integration of natural flame retardants to PLA involving bio‐based plasticizer enables to use of environmentally friendly composites in conditions where fire resistance performance is required. In the current study, ductile green fire retardant PLA composites were manufactured using hydromagnesite&huntite (HH) as a natural fire retardant additive and acetyl tributyl citrate as a bio‐based plasticizer. The influences of plasticizer and HH contents on the fire retardant, thermal and mechanical performances of the composites were explored. According to test results, the limiting oxygen index (LOI) value of PLA reduced from 29.2 to 28.0 and the UL‐94 V rating changed from V2 to BC with the addition of 20 wt% plasticizer owing to the reduction in melt viscosity. The peak heat release rate (pHRR) and average heat release rate (avHRR) values increased steadily as the concentration of plasticizer increased due to the formation of a more porous residue structure stemming from the increased transportation rate of gases. In order to produce ductile flame retardant material, the plasticizer content was required to 20 wt% of HH. The highest LOI value (36.2) and UL‐94 rating of V0 were achieved with the inclusion of 70 wt% HH in the presence of 20 wt% plasticizer. Improvement in impact resistance and reduction in tensile strength were observed as the added amount of plasticizer increased.

Bio-inspired nacre-like composites with excellent mechanical properties, gas-barrier function and fire-retardant performances based on self-assembly between hyperbranched poly(amido amine)s and montmorillonite.

The fabrication of mechanically robust multifunctional nanocomposite (NC) films using simple but effective strategies is a long-term challenge. Inspired by natural nacre, we designed and fabricated high-performance nacre-like NC films (Na-MTM/HBP) through the self-assembly of the hyperbranched poly(amido amine) (HBP) and montmorillonite (Na-MTM) using a vacuum filtration approach. The optimal Na-MTM/HBP NC film shows excellent mechanical strength (106 MPa), which can be attributed to the formation of numerous hydrogen bonds and the electrostatic interactions between hyperbranched HBP and Na-MTM nanosheets. Such films also exhibit excellent gas barrier and fire-fire-retardant owing to the high aspect ratio of the Na-MTM nanosheets. In this work, a class of high-performance NC films exhibiting good mechanical, gas barrier, and flame retardancy properties have been developed. These NC films have great potential in packing or coating materials.

The synergistic effect of inorganic hybrid nanofibers and phytic acid-based nanosheets towards improving the fire retardancy and comprehensive performance of epoxy resin

The synergistic effect of inorganic hybrid nanofibers and phytic acid-based nanosheets towards improving the fire retardancy and comprehensive performance of epoxy resin

Electrical Tracking, Erosion and Fire Retardancy Performance of Silicone Rubber Insulation Containing Aluminum Trihydrate, Graphene and Glass Fiber Additives

Electrical Tracking, Erosion and Fire Retardancy Performance of Silicone Rubber Insulation Containing Aluminum Trihydrate, Graphene and Glass Fiber Additives

Bio-Inspired Aramid Fibers@silica Binary Synergistic Aerogels with High Thermal Insulation and Fire-Retardant Performance

Flame-retardant, thermal insulation, mechanically robust, and comprehensive protection against extreme environmental threats aerogels are highly desirable for protective equipment. Herein, inspired by the core (organic)-shell (inorganic) structure of lobster antenna, fire-retardant and mechanically robust aramid fibers@silica nanocomposite aerogels with core-shell structures are fabricated via the sol-gel-film transformation and chemical vapor deposition process. The thickness of silica coating can be well-defined and controlled by the CVD time. Aramid fibers@silica nanocomposite aerogels show high heat resistance (530 °C), low thermal conductivity of 0.030 W·m-1·K-1, high tensile strength of 7.5 MPa and good flexibility. More importantly, aramid fibers@silica aerogels have high flame retardancy with limiting oxygen index 36.5. In addition, this material fabricated by the simple preparation process is believed to have potential application value in the field of aerospace or high-temperature thermal protection.

Solid‐state NMR characterization of multi‐component intumescent flame retardant polybutylene succinate formulations

AbstractIn this work, a series of multi‐component intumescent PBS formulations were elaborated by the combination of intumescent flame retardant (IFR) system (consisting of ethylenediamine phosphate and melamine poly(aluminum phosphate), 7:3, wt:wt) and synergists. Three boron/zinc‐containing compounds (i.e., melamine borate, zinc oxide, zinc carbonate) were examined as potential synergists to improve the fire behavior and fire retardancy of PBS. The MLC results showed that the incorporation of all of these compounds enhanced the fire retardancy of PBS to some extent. Among them, zinc oxide exhibited the best fire retardant performances in terms of reduction of the peak heat release rate (pHRR, −61%), fire growth rate index (FIGRA, −19%), maximum average rate of heat emission (MARHE, −55%), and increase of the time to pHRR (+370 s) and to flameout (+650 s) as compared to PBS/IFR10%. Furthermore, the effect of zinc oxide loading on the fire retardancy of PBS was also investigated, the results showed that 2 wt.% loading exhibited the best performances. Solid‐state NMR characterization indicated that the presence of ZnO resulted in the formation of a crack‐free and dense intumescent char layer reinforced by complex aluminum‐zinc‐phosphates glassy species. The intumescent char layer provided a protective physical barrier with improved flexibility and cohesion, which effectively limits the heat and mass transfer between condensed and gas phases and hence, improving the fire retardancy of PBS.