Horizontal Burning Test Research Articles

Improvement of the flame retardancy of polyamide 6 by the incorporation of UiO-66 and UiO-66/melamine

The flame retardancy of polyamide 6 (PA6) has been investigated through the incorporation of the metal–organic framework (MOF) UiO-66 and a composite of UiO-66/melamine during the extrusion process. The prepared materials have been characterised by various techniques: XRD, XPS, FTIR, TGA, DSC, SEM, EDX and mechanical properties. Moreover, to examine the efficiency of the flame retardants, the composites have been tested using the UL-94 vertical and, horizontal burning test, as well as the limiting oxygen index (LOI). The UL-94 V-2 standard has been achieved with only a 4 wt% load of either UiO-66 or UiO-66/melamine, compared to pure polyamide, which is not classified. The best results have been achieved with the UiO-66/melamine sample at 7 wt%, which prevents the agglomeration of UiO-66 alone. The highest LOI value was also obtained with this sample, achieving a value of 35.5 %, compared to pure PA6 and with UiO-66, which reached values of 22.4 % and 23.2 %, respectively. A flame suppression mechanism of the UiO-66/melamine composite is proposed, based on the formation of zirconium oxide, gas adsorption by the MOF and release of NH3.

Eco‐friendly flame‐retardant based on sap from banana plant pseudostems

AbstractSociety's need for safe flame‐retardant technologies in passive fire protection is undeniable. To address this concern, this paper presents an experimental investigation of the fire‐retardant properties of slash pine wood treated with banana plant pseudostem sap, obtained from a cultivated banana plant variety widely grown in Brazil. The natural sap extract was characterized through X‐Ray Fluorescence spectrometry and Fourier Transform Infrared Spectroscopy techniques, revealing the presence of key components, including water, potassium chloride, sodium chloride, sodium silicate, calcium phosphate, sodium phosphate, lignin and tannins. The authors explored different treatment parameters, including various sap impregnation times, number of impregnations and use of natural versus various levels of concentrated sap. First, a horizontal burning test, similar test to UL 94 HB, was used to obtain an initial assessment of the suitability of sap as a flame retardant for slash pine wood. Subsequently, the Mass Loss Calorimeter equipment with thermopile attachment described in ISO 13927:2015 was used to measure various heat release rate parameters. The findings suggest that reducing the water content in sap and increasing the number of repeat treatments results in a more effective treatment for slash pine wood. More specifically, the results indicate that the most efficient treatment involves three impregnations with high‐concentration (1/10 volume reduction) sap. Future work to improve the efficacy of the concentrated sap impregnation process could explore the use of pressure treatment instead of soaking.

Flame retardancy and mechanical properties of polypropylene composites containing intumescent flame retardants, preceramic polymers, and other additives

AbstractThis study aims to investigate the flame retardancy and mechanical properties of polypropylene (PP)‐based intumescent flame retardants (IFRs) consisting of melamine phosphate (MP) and pentaerythritol (PER), and different additives; boron phosphate (BP), antimony oxide (AO), and preceramic polymers, namely poly(dimethylsilane) (PDMS) and poly(methylsilsesquioxane) (PMSQ). The composites were produced by twin‐screw extrusion, and then molded by injection molding. Their characterizations were performed with limiting oxygen index (LOI), horizontal burning tests, thermogravimetric analysis (TGA), tensile and impact tests. The total amount of IFRs and the additives in polypropylene was kept constant at 20 wt%. The additive concentration was varied as 1, 3, and 5 wt% in the composites. The highest LOI value of 29% was obtained for PP/MP/PER composite with MP/PER ratio of 3/1. PP/IFR‐based composites with 1 wt% additive exhibited higher LOI and horizontal burning performance than the other composites with 3 and 5 wt% additives. It is revealed that tensile modulus and impact strength of neat PP were improved with the addition of IFRs, and for each type and amount of the additives used in the study.Highlights Usage of IFRs, preceramic polymers, BP and AO in PP improved flame retardancy. Lower amount of additives (1%) in PP/IFR composites led to higher LOI values. Additive incorporation enhanced tensile modulus and impact strength of neat PP.

Assessing the Efficacy of Magnesium Hydroxide and Aluminium Hydroxide in Enhancing Flame Retardancy of Natural Fiber

Natural fiber panels have gained attention as sustainable alternatives in various applications, including construction and interior design. Although these fibres are highly valued for their environmental sustainability and acoustic advantages, they are inherently flammable. These panels, when subjected to fire or high-temperature conditions, pose significant safety risks due to their flammability and potential for rapid combustion. This study evaluates the efficacy of various synthetic additives in enhancing the flame retardancy of natural fiber panels. The panels were made by mixing the natural fiber with polyester resin and additives. The experimental setup includes standard fire tests such as ASTM D635 Horizontal Burning and ASTM D3801 Vertical Burning Test. The results show that rice husk demonstrates a slower burning rate when combined with both magnesium hydroxide and aluminium hydroxide, indicating better flame retardancy. Coconut coir outperforms rice husk and sawdust for both magnesium hydroxide and aluminium hydroxide which are 655 s and 640 s respectively in terms of vertical burning. The study showed that magnesium hydroxide is a better flame retardant than aluminium hydroxide. This makes it a promising option for enhancing the fire resistance of natural fiber panels.

Improving Fire Resistance in E-Vehicles: A Study on MPP-Enhanced S-Glass/Phenolic Hybrid Composites

The automotive industry has benefited greatly from the advancements in fireproof, high-strength fiber-reinforced polymer matrix composites during the last several decades. S-Glass/Phenolic hybrid composites made by hydraulic compression molding are the subject of this investigation into the effects of Melamine Polyphosphate (MPP) on their thermal and fire performance. In addition to studying the morphology of the samples, researchers analyzed the thermal and fire performances of hybrid laminates made with neat laminates and varying compositions of MPP (ranging from 3% to 15% by weight). Tests included UL 94, limiting oxygen index (LOI), and the impacts of accelerated heat ageing on the behavior of the hybrid specimens. The results demonstrated that specimens filled with higher MPP performed better in a fire compared to neat samples. According to the results in UL 94 horizontal burning test and vertical burning test, specimens filled with 12 and 15 wt. % MPP demonstrated a reduced flame spreading rate and fulfilled the V-0 criteria. Simultaneously, the energy absorption capacity of hybrid configurations is severely limited by heat ageing, due to its temperature and duration dependent. The research proved that the suggested S-Glass / Phenolic / Melamine Polyphosphate hybrid composites were suitable for creating environmentally friendly electric vehicle battery housings and fire-resistant automotive parts.

Nano Boron Oxide and Zinc Oxide Doped Lignin Containing Cellulose Nanocrystals Improve the Thermal, Mechanical and Flammability Properties of High-Density Poly(ethylene).

The widely used high-density polyethylene (HDPE) polymer has inadequate mechanical and thermal properties for structural applications. To overcome this challenge, nano zinc oxide (ZnO) and nano boron oxide (B2O3) doped lignin-containing cellulose nanocrystals (L-CNC) were blended in the polymer matrix. The working hypothesis is that lignin will prevent CNC aggregation, and metal oxides will reduce the flammability of polymers by modifying their degradation pathways. This research prepared and incorporated safe, effective, and eco-friendly hybrid systems of nano ZnO/L-CNC and nano B2O3/L-CNC into the HDPE matrix to improve their physio-mechanical and fire-retardant properties. The composites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, thermo-gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, horizontal burning test, and microcalorimetry test. The results demonstrated a substantial increase in mechanical properties and a reduction in flammability. The scanning electron microscope (SEM) images showed some agglomeration and irregular distribution of the inorganic oxides.

Flammability and Soil Burial Performance of Sugar Palm (Arenga pinnata (wurmb) merr) Fiber Reinforced Epoxy Composites

This study investigates the effects of soil burial and flammability on sugar palm fibre (SPF) (Arenga pinnata (wurmb) merr)-reinforced epoxy composites. In order to determine the flammability and biodegradability properties, experiments are conducted in accordance with ASTM standards. The hand lay-up method was used to fabricate composite samples with two different weight ratios between epoxy and SPF, which were 70:30 and 50:50. Biodegradability and flammability properties were investigated using horizontal burning tests, limiting oxygen index (LOI), cone calorimetry, and soil burial. It was found that the Epoxy/SPF-50 was the composite that exhibited the fastest degradability at 0.81%/week. The result of the horizontal burning test showed that the addition of SPF reduced the burning rate but slightly increased it at 50 wt% because the ratio between epoxy and SPF exceeds the optimum fibre loading. The Epoxy/SPF-50 exhibited a better LOI value at 23.3 than pure epoxy (control), which was 19.8. From the cone calorimetry test, it was observed that the time to ignition (TTI) and total heat release (THR) values were decreased when the amount of SPF increased. Char production increases the flame-retardant protection of SPF-reinforced epoxy composites. To the best of the authors’ knowledge, no published study has been conducted on the flammability and biodegradability characteristics of SPF-reinforced epoxy composites.

Effect of Rice Husk and Wood Flour on the Structural, Mechanical, and Fire-Retardant Characteristics of Recycled High-Density Polyethylene.

Given the rising consumption of plastic products, it is becoming imperative to prioritize the recycling of plastic items as a solution to reducing plastic waste and environmental pollution. In this context, this research focuses on assessing the impact of incorporating rice husk and wood flour into recycled high-density polyethylene (rec-HDPE) to analyze its mechanical properties, flammability, and thermal stability. The combined rec-HDPE content of wood flour and rice husk varied between 0% and 20%. The rec-HDPE content of maleic anhydride grafted polyethylene (MAPE) was fixed at 3%. Mechanical characteristics such as flexural, tensile, and impact strengths were assessed. Cone calorimetry (CC) tests, limited oxygen index (LOI) tests, and horizontal and vertical burning tests were performed to determine the flammability or fire retardancy of these composites. On the other hand, to characterize the thermal characteristics of these composites, thermogravimetric analysis (TGA) was used. To further characterize the fluctuation in these characteristics, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) studies were carried out. The mechanical characteristics were found to be increased in response to adding rice husk or wood flour. An 8% increase in tensile strength and a 20% increase in elastic modulus enhancement were recorded for a 20% rice husk-added composite. SEM revealed the reason for the variation in tensile properties, based on the extent of agglomeration and the extent of uniform distribution of fillers in rec-HDPE. Following these lines, the 20% rice husk-added composite also showed a maximum increase of around 6% in its flexural strength and a maximum increase of 50% in its flexural modulus. A decrease in impact strength was recorded for rice husk and wood flour-reinforced composites, compared with unreinforced rec-HDPE. Hybrid composites displayed a lack of mechanical strength due to changes in their nature. FTIR tests were performed for a much more elaborate analysis to confirm these results. Twenty percent of rice husk-added rec-HDPE displayed the best thermal properties that were tested, based on TGA and derivative thermogravimetric (DTG) analysis. This 20% composite also displayed the best fire-retardancy characteristics according to UL 94 tests, cone calorimetry tests, and limited oxygen index tests, due to the barrier created by the silica protective layer. These tests demonstrated that the incorporation of both fillers-rice husk and wood flour-effectively enhanced the thermal, mechanical, and fire-retardant attributes of recycled HDPE.

Aryloxyphosphazene-Modified and Graphite-Filled Epoxy Compositions with Reduced Flammability and Electrically Conductive Properties

A method has been developed for producing an epoxy composition based on a low-viscosity epoxy-resorcinol resin, a phosphazene-containing curing agent, isophoronediamine, and thermally expanded graphite as a filler. The degree of cure and the absence of side reactions during the curing process were confirmed using IR spectroscopy. The influence of the content of phosphazene-containing curing agent and filler on the physico-mechanical properties of the composition, its fire resistance, and antistatic properties were studied. Using the UL-94 HB horizontal burning test, it was found that the addition of 10 and 20 wt. % phosphazene-containing curing agent (relative to isophoronediamine) reduces the burning speed by 10 times compared to a sample without phosphazene. The addition of a filler to a composition containing phosphazene reduces the burning speed by 25 times compared to a composition without phosphazene and imparts antistatic properties to the epoxy composition, as evidenced by the specific volume electrical resistance of the order of 101 Ohm·m. Phosphazene-containing curing agent had no statistically significant effect on specific volume electrical resistivity (p > 0.05). Tests of physico-mechanical and adhesive properties (tensile strength, compressive strength, water absorption, water solubility, abrasion resistance, and adhesive strength) of filled epoxy compositions with 10 and 20 wt. % phosphazene-containing curing agent demonstrated that these properties met the requirements for floor coverings in construction and parts of electrical devices.

Fully bio-based fire-safety composite from cotton/viscose wastes and alginate fiber as furniture materials

The increasing demand of textiles and apparel as global economy booms deepens environmental crisis associated with excessive textile waste disposed by landfill or incineration. This work implemented an eco-friendly and sustainable strategy to recycle up to 50 wt% textile waste with marine bio-based calcium alginate fiber into fire-proof fully bio-based composite textile by carding process. Incorporation of intrinsic nonflammable calcium alginate fibers endowed these needle-punching bio-composite felt with excellent inherent flame retardancy and improved safety. Horizontal burning test showed that by mixing with alginate fiber in proper ratio and pattern, extremely flammable cotton fiber and viscose fiber became totally inflammable. Analysis revealed that the generation of CaCO3 char residue and gaseous volatile of H2O inhibited the diffusion of O2 and heat, contributing to the outstanding fire proof performance of produced composite felt. The improved safety was affirmed by cone calorimetry test. It demonstrated limited heat, smoke and toxic volatile compound in the burning, as well as production of CO and CO2. All results showed that a straightforward yet economical method could recycle textile waste fibers into fully bio-based, fireproof and greener products, a potential candidate as fireproof structural filling and insulation materials for household textile or construction material.

Synergistic Adenosine Triphosphate/Chitosan Bio-coatings on Polyurethane Foam for Simultaneously Improved Flame Retardancy and Smoke Suppression

Considering that fire safety is a persistent problem for most polymeric materials, including polyurethane (PU) foam, the demand for flame retardants (FRs) is growing. However, the use of conventional FRs containing halogenated and brominated chemicals has been continuously regulated owing to their toxicity. Here, we demonstrate the layer-by-layer (LbL) coating of negatively charged adenosine triphosphate (ATP) and positively charged chitosan (CS) as the synergistic FR on PU foam, a model flammable polymer material. The FR performance of the PU coated with LbL-assembled ATP and CS (ATP/CS-PU) was tested, and the results suggested that the ATP/CS layers were finely deposited on the surface of the PU without damaging the structure. Only five bilayers (5BL) were sufficient to impart excellent fire retardancy, which exhibited a limiting oxygen index value of 35% and the HF-1 rating in the UL94 foamed material horizontal burning test. In addition, ATP/CS(5BL)-PU showed a significant reduction in the peak heat release rate of 42.0% and in the total smoke release of 30.6% compared to that of bare PU (b-PU). Furthermore, the ATP/CS coatings did not deteriorate the mechanical properties of b-PU. Finally, combined thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) showed that ATP/CS(5BL)-PU was safe because it suppresses hazardous gases, which is the main problem with conventional FRs.

Mechanical, Thermal, and Fire Retardant Properties of Rice Husk Biochar Reinforced Recycled High-Density Polyethylene Composite Material.

This study concentrated on the influence of rice husk biochar on the structural, thermal, flammable, and mechanical properties of recycled high-density polyethylene (HDPE). The percentage of rice husk biochar with recycled HDPE was varied between 10% and 40%, and the optimum percentages were found for the various properties. Mechanical characteristics were evaluated in terms of the tensile, flexural, and impact properties. Similarly, the flame retardancy of the composites was observed by means of horizontal and vertical burning tests (UL-94 tests), limited oxygen index, and cone calorimetry. The thermal properties were characterized using thermogravimetric analysis (TGA). For detailed characterization, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) tests were performed, to elaborate on the variation in properties. The composite with 30% rice husk biochar demonstrated the maximum increase in tensile and flexural strength, i.e., 24% and 19%, respectively, compared to the recycled HDPE, whereas the 40% composite showed a 22.5% decrease in impact strength. Thermogravimetric analysis revealed that the 40% rice husk biochar reinforced composite exhibited the best thermal stability, due to having the highest amount of biochar. In addition, the 40% composite also displayed the lowest burning rate in the horizontal burning test and the lowest V-1 rating in the vertical burning test. The 40% composite material also showed the highest limited oxygen index (LOI), whereas it had the lowest peak heat release rate (PHRR) value (52.40% reduced) and total heat release rate (THR) value (52.88% reduced) for cone calorimetry, when compared with the recycled HDPE. These tests proved that rice husk biochar is a significant additive for enhancing the mechanical, thermal, and fire-retardant properties of recycled HDPE.

The effects of various flame retardants on the combustion of polypropylene: Combining optical diagnostics and pyrolysis fragment analysis

The assessment of the efficacy and mode of action of flame retardants in polymers requires a thorough knowledge of the coupling of the presence of chemical inhibitors with the underlying heat and mass transport processes. In this experimental work, we combine a thermal decomposition analysis with optical combustion diagnostics in different test environments to gain a comprehensive understanding of the relevant sub-processes and demonstrate how this approach provides future opportunities for the research regarding the mode of action of flame retardants. Four different composites of polypropylene (PP) and 10 wt% of selected flame retardants as well as neat PP are prepared. Flame retardants include pentaerythritol spirobis(methylphosphonate) (PSMP), zinc diethylphosphinate (DEPZn), aluminum hydroxide (i.e. aluminum trihydrate, ATH) and ammonium polyphosphate (APP). The released substances in the gas phase are investigated by using thermogravimetric analysis coupled to Fourier-transform infrared spectroscopy (TGA-FTIR), and the burning behavior regarding carbon monoxide concentration and heat release rate (HRR) is studied in cone calorimeter experiments. The ignition and combustion of flame retarded micrometer-sized particles of PP are experimentally investigated in a laminar flat flame burner by means of simultaneous scanning planar laser-induced fluorescence of OH radicals (OH-PLIF) and diffuse back-illumination (DBI) at a repetition rate of 10 kHz. Particles with gas-phase activity show a decreased normalized OH signal intensity during combustion. A dependency of the dimensionless flame radius on the particle size is found which can be linked to the faster heating and pyrolysis of smaller particles compared to large particles and agglomerations. Eventually, the interaction with an external premixed flame and the subsequent extinction of self-sustaining flames of polymer sticks is investigated using OH-PLIF in an adapted horizontal burning test suited for the application of optical diagnostics. This approach allows to link the findings of investigations encompassing multiple scales, resulting in a thorough understanding of both polymer chemistry and combustion dynamics in flame retarded polymers.

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.

Layer-by-layer assembly of calixarene modified GO and LDH nanostructures on flame retardancy, smoke suppression, and dye adsorption behavior of flexible polyurethane foams

In this study, the effect of LbL coatings based on layered double hydroxide (LDH), graphene oxide (GO), and sodium p-sulfonatocalix[4]arene (SC4A) modified graphene oxide (GOSC4A) on the fire properties and dye adsorption behavior of flexible polyurethane foam was investigated. For this purpose, samples including neat PU foam and modified PU foams with 3, 6, and 9 bilayers of LDH-GO and LDH-GOSC4A coatings were prepared. SEM micrographs of the prepared foams confirmed the presence of LDH-GO and LDH-GOSC4A coatings on the foam surface and showed that the LDH-GOSC4A layers form a denser and more uniform coating on the PUF surface. Combustion studies of prepared foams using CCT and horizontal burning test demonstrated that at the same number of bilayers, foams including LDH-GOSC4A coatings showed better flame retardancy than LDH-GO coated foams. Therefore, the PUF/LDH-GOSC4A 9BL foam showed the best fire properties, and its PHRR, THR, and TSP values ​​were reduced by 28.8, 11.8, and 36.3%, respectively, compared to uncoated PUF. Methylene blue (MB) adsorption studies revealed that adsorption of MB onto PUF/LDH-GOSC4A 9BL is well consistent with the pseudo-second-order kinetic model and its maximum adsorption capacity is 38.46 mg/g based on the Langmuir isotherm equation.

Enhanced flame resistance of cellulose aerogel by ammonium polyphosphate for heat insulation

Cellulose aerogels are a potential candidate for heat insulation, but one of their drawbacks is high flammability hindering their applications in practice. This study synthesized cellulose aerogels from microfibrillated cellulose fibers (MFC) extracted from discarded pineapple leaves. The procedure started with simply mixing the extracted fibers with polyamide amine-epichlorohydrin (PAE) as a chemical crosslinker and ammonium polyphosphate (APP) (10-20%) as a green and effectively flame-resistant additive, followed by freeze-drying. The produced aerogels are characterized in terms of their morphology, thermal stability and conductivity, and flame resistance via advanced and standardized methodologies including Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), thermal conductivity measurement by a heat flow meter, and UL94 horizontal burning test. The flame-resistant cellulose aerogels exhibit ultra-low density (25.5-26.8 mg/cm3), high porosity (98.0-98.2%), excellent heat insulation (35.9-36.7 mW/m۰K), and are completely flame-resistant. In addition, the varied APP content (10-20%) shows little effect on the density, heat conductivity, and thermal stability of the flame-resistant cellulose aerogels in comparison with that of the neat cellulose aerogel. Based on the findings, the synthesized flame-resistant cellulose aerogels are considered a promising bio-based heat insulation material.

Potential applications of basalt fibre composites in thermal shielding

This present study demonstrates the applicability of basalt fibre-reinforced polymer (BFRP) composite materials in thermal shielding. Basalt fibres are produced from natural, sustainable sources and obtain comparable mechanical performance to commercial glass fibres. In addition to their mechanical strength, BFRPs have excellent chemical and heat resistance. Basalt fibres tend to have a higher thermal stability than their competitor glass fibres. The heat resistance of basalt fibres derives from the volcanic origin of the raw material basalt gabbro. These favourable features make BFRP composites an attractive group of materials for application in several industries. To test the fire resistance of the materials, we produced mono and hybrid composite plates from different types of basalt reinforcement structures (milled fibres, chopped fibres and woven fabric) and epoxy resin. Surface treatment with silane coupling agents significantly improved the mechanical and thermomechanical properties of BFRPs by up to 70%. Three-point bending tests were performed to determine the flexural properties of the composite specimens, and their fire behaviour was evaluated with a horizontal burning test, and a novel jet fire test assisted with infrared thermal imaging. Higher fibre content in hybrid laminates decreased the linear burning rate by 8%, and the maximum surface temperature was approximately 80 °C lower after jet fire impingement compared to woven reinforcement structure.

Effect of ammonium polyphosphate on fire‐retardant, mechanical, and vibrational analysis of epoxy/glass/ramie hybrid composite

AbstractHybrid polymer composites (synthetic and/or natural fiber) are highly prominent in the fields of automotive, aerospace, construction, and marine. This work aims at developing a novel epoxy/glass/ramie (EGR) hybrid composite incorporated with ammonium polyphosphate (APP) using a vacuum bag technique, thus by changing the weight percentage of APP. The hybrid composites were characterized for the fire‐retardant (vertical and horizontal burning test), mechanical (hardness, tensile, and flexural testing), wettability, porosity (ethanol infiltration), and vibrational properties. The flammability data show that the hybrid composites made of 10, 15, and 20 weight percentages of APP obtained V‐1, V‐0, and V‐0 grades in the UL‐94 vertical burning test. Furthermore, there is an enhancement in hardness properties, but it reduces the tensile and flexural strength. However, the integration of APP reduces the water absorption rate of the composite from 11% to 5%. This study found that APP‐reinforced EGR hybrid composite improves fire resistance, thereby reducing the water absorption rate, which hikes the usage of the material for structural application.

Ethylene-propylene-diene (5-ethylidene-2-norbornene) terpolymer/aluminium hydroxide nanocomposites: Thermal, mechanical and flame retardant characteristics

Ethylene-propylene-diene rubber (EPDM) composites were fabricated by incorporating aluminium hydroxide (ATH) and high abrasion furnace (HAF) carbon black using two-roll mill mixing strategy. The thermal stability, flammability and mechanical properties of the composites were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), horizontal burning test (UL94 HB), mechanical testing (UTM) and dynamic mechanical analysis (DMA). TGA profiles showed that,EPDM/ATH composites presented incremented char residue and reduced mass loss rate compared to control EPDM. The incorporation of ATH was found to benefit the flame retardancy of composites. The storage modulus (E’) of composites peaked due to the increased stiffness of the material with filler loading. Investigation of visco-elastic properties showed the existence of strong polymer - filler interaction. The morphology of the composites under study and the corresponding char residue obtained after their LOI testing were investigated by scanning electron microscopic studies (SEM).

Flame retardant and anti-dripping surface treatment through a co-deposition of polydopamine/polyphosphonamide for fabric and foam materials

High efficient flame retardant surface treatment through a simple and universal strategy has attracted considerable interest. In this work, polyphosphonamide (PPA) was synthesized via an eco-friendly amine ester exchange reaction, and then the polydopamine-polyphosphonamide (PDA-PPA) coating was constructed by a mussel-inspired phenol-amine co-deposition on the surface of various substrates (cotton, polyethylene terephthalate, poly (lactic acid), polyamide, polypropylene fabrics, and flexible polyurethane foam). It was demonstrated that the PDA-PPA coating significantly improved the flame retardancy of the six substrates. For example, in the case of PDA-PPA coated cotton fabric sample, the limiting oxygen index was increased to 28.3%, the peak of heat release rate and total heat release was decreased by 70.6% and 48.2%, respectively. Especially in the vertical and horizontal burning tests, all PDA-PPA coated samples were self-extinguished and free of molten droplets. It was suggested that the PDA-PPA coating released P-containing radicals to capture active small free radicals and released non-combustible gases to dilute combustible volatiles in the gas phase. In addition, the coating showed excellent intumescent charring ability and promoted the char formation of all substates except polypropylene. Surprisingly, the coating also improved the breaking strength of the PDA-PPA coated fabric and the compressive stress of the PDA-PPA coated foam samples. It was believed that this work provides a scalable and promising strategy for preparing fire safety polymeric materials with a large specific surface area.