Flame Retardant Materials Research Articles

A Systematic Investigation on the Effect of Carbon Nanotubes and Carbon Black on the Mechanical and Flame Retardancy Properties of Polyolefin Blends.

Due to high filler loading, clean, commercial, thermoplastic, flame-retardant materials are mechanically unstable when insulating wires and cables. In this study, composite formulations of linear low-density polyethylene (LLDPE)/ethylene-vinyl acetate (EVA) containing a flame retardant, such as magnesium hydroxide (MH; formula: Mg(OH)2) and huntite hydromagnesite (HH; formula: Mg3Ca(CO3)4, Mg5(CO3)4(OH)2·3H2O), were prepared. The influence of carbon nanotubes (CNTs) and carbon black (CB) on the mechanical properties and flame retardancy of LLDPE/EVA was studied. Three types of CNTs were examined for their compatibility with other materials in clean thermoplastic flame-retardant compositions. The CNTs had the following diameters: 10-15 nm, 40-60 nm, and 60-80 nm. Optimum mechanical flame retardancy and electrical properties were achieved by adding CNTs with an outer diameter of 40-60 nm and a length of fewer than 20 nm. Large-sized CNTs result in poor mechanical characteristics, while smaller-sized CNTs improve the mechanical properties of the composites. CB enhances flame retardancy but deteriorates mechanical properties, particularly elongation at break, in clean, black, thermoplastic, flame-retardant compositions. Obtaining satisfactory compositions that meet both properties, especially formulations passing the V-0 of the UL 94 test with a minimum tensile strength of 9.5 MPa and an elongation at break of 125%, is challenging. When LLDPE was partially substituted with EVA, the limiting oxygen index (LOI) increased. The amount of filler in the formulations determined how it affected flammability. This study also included a reliable method for producing clean, black, thermoplastic, flame-retardant insulating material for wire and cable without sacrificing mechanical properties.

Research on modification of polylactic acid multifunctional composite materials for 3d printing

Polylactic acid is an important 3D printing material, but its further development and application in the field of 3D printing are limited due to its flammability, poor toughness, and lack of high temperature resistance. This article modifies polylactic acid wire for 3D printing by adding flame retardants aluminum hypophosphate, polycarbonate, and chain extender to prepare multifunctional composite flame retardant materials. It was found that with the increase of aluminum hypophosphate addition, the flame retardancy of polylactic acid composite materials gradually improved, while the tensile strength, impact strength, and hardness showed a decreasing trend, and the flowability decreased, but the Vicat softening temperature increased. Through 3D printing testing, when the amount of aluminum hypophosphate added is 15-20 parts, the printing quality is good and the comprehensive performance is the best, which can meet the basic usage requirements.

Enhancing Flame Retardancy and Thermal Insulation Performance of Silicone Rubber Composites Using Silicon Carbide

This study focuses on modifying silicone rubber using silicon carbide (SiC) to enhance the flame retardancy and thermal insulation properties of the composites. The study characterizes the thermal stability, mechanical properties, and flame retardancy of the composite materials. The results demonstrate the effective improvement in thermal stability achieved by incorporating SiC into the silicone rubber composites. At a SiC addition level of 6 wt.%, the composite material shows optimal thermal stability with an initial decomposition temperature of 487°C, which is 84°C higher compared to the pure matrix. Additionally, the SiC/SR composites system exhibits a char yield of 72.13% at 900°C, representing an approximately 9% increase compared to the pure SR matrix. Simultaneously, the incorporation of SiC significantly enhances the flame retardancy of silicone rubber. At a SiC addition level of 10 wt.%, the LOI (Limiting Oxygen Index) value increases by 10.5% to reach 30.4%, surpassing the non-additive sample. Moreover, the UL-94 classification of the composite material is V-0, meeting the standard for flame retardant materials.

Preparation of thermally stable and flame‐retardant sugarcane bagasse‐ammonium dihydrogen phosphate/epoxy composites and their performance

AbstractEpoxy resin was often applied in fiber‐reinforced composite materials, adhesives, and encapsulation materials. However, epoxy was easily flammable and limited its usage in certain applications. The study recycled and reused agricultural waste sugarcane bagasse to prepare a halogen‐free bio‐based intumescent flame retardant and then mixed with epoxy resin to prepare a composite containing polymer with improved thermal properties and flame retardancy of the materials. The work followed the concept of circular economy and sustainability. Bagasse‐ammonium dihydrogen phosphate (ADP) flame retardant was added to an epoxy resin to prepare epoxy/bagasse‐ADP composites, an effective flame‐retarding composite material through hydrothermal method. Adding bagasse‐ADP increased the thermal stability and flame retardancy of the composite materials compared with that of pure epoxy. For the material with 30 wt% added bagasse‐ADP, the char yield was 32.3 wt%, which was 18.2 wt% higher than that of pure epoxy (14.1 wt%) through thermogravimetric analysis. In addition, the limiting oxygen index increased from 21% to 30%, and the UL‐94 classification improved from “Fail” to “V‐0.” This performance was attributed to the nitrogen, phosphorus, and silicon content of the flame retardant.

Dimensional change of red phosphorus into nanosheets by metal–organic frameworks with enhanced dispersion in flame retardant polyurea composites

Red phosphorus (RP) is a promising polymeric flame retardant due to its abundance of flame-retardant elements. Unfortunately, the irregular size of RP leads to poor dispersion in polymer matrices, which greatly limits its wide application in flame-retardant polymer materials. Here, RP is transformed into a two-dimensional (2D) lamellar structure by a simple green method, while ZIF-67 nanoparticles are grown in situ and uniformly embedded in them. The 2D porous RP@ZIF (2D RP@ZIF) composites exhibit excellent flame-retardant properties and mechanical properties in polyurea (PUA) matrix. The peak heat release rate, total heat release, the peak of smoke production rate and total smoke production of PUA composites added with 5 wt% 2D RP@ZIF decreased by 48.0 %, 54.2 %, 20.4 % and 22.2 %, respectively. Due to its well compatibility, the elongation at break and tensile strength of PUA composites were 308.02 % and 9.21 N in the mechanical test, respectively. Compared with previous work, this is the first time that a 2D RP hybrid flame retardant has been prepared by metal organic framework and applied to flame retardant PUA.

Preparation and properties of halogen-free flame retardant PE based wood-plastic composite materials

ABSTRACT The experiment carried out halogen-free flame retardant modification treatment on polyethylene-based wood-plastic composite materials. The results showed that after adding flame retardant, the ignition time of the material increased to 76 seconds, an increase of 22 seconds. At combustion temperatures above 530°C, only a small amount of the material’s residue continues to evaporate. When the temperature rises to 800°C, the difference in the residual carbon content of the samples gradually becomes larger. The residual carbon content of sample 1# is only 10.1%. At this time, the residual carbon content of samples 7#, 8# and 9# are respectively Reaching 27.12%, 27.09% and 25.60%. The above results show that the thermal stability of composite materials has been greatly improved after adding nano-flame retardants, providing new ideas and methods for the application of flame retardant and halogen-free flame retardant materials of wood-plastic composites.

Investigation on the battery thermal management and thermal safety of battery-powered ship with flame-retardant composite phase change materials

Pure battery-powered ships have attracted much attention because of its unique advantages of zero-emission. However, the problems of adaptability to extreme working conditions and thermal safety risks restrict the development of battery-powered ships. In this study, a novel flexible flame-retardant composite phase change materials (CPCM) with paraffin (PA)/EVA grafted on maleic anhydride (EVA-g-MAH)/expanded graphite (EG)/ammonium polyphosphate (APP)/triphenyl phosphate (TPP)/Na2SiO3 has been proposed and utilized in battery module. Among them, the sample ATPCM2 with APP/TPP/Na2SiO3 ratio of 5/10/10 achieved the optimal thermal properties and flame-retardant effect. The designed multifunctional CPCM harmonizes the competition between flame retardancy, mechanical properties and phase change latent heat by the synergistic effect. Besides, the ATPCM2-Module shows a good temperature control performance during charge-discharge cycles, such as the maximum temperature of battery module can be still controlled below 50 °C at 2C discharge rate and the corresponding temperature difference was effectively maintained within 4.1 °C. This is owing to the constructed stable three-dimensional heat conductive skeleton formed by synergistic flame retardancy effect, which could improve the dissipation heat capacity and thermal safety. With these prominent performances, the designed flexible CPCM with desired flame-retardant and thermal management performance can provide insights into the passive thermal management and thermal safety improvement of both battery-powered ships and high-power battery module under extreme conditions.

Study on the inhibition of explosion and combustion of coal dust based on the structure of core-shell microencapsulated polyurethane

In order to study the effect of core-shell microencapsulated ammonium polyphosphate modified materials on the suppression of explosion and combustion of different metamorphic coal, a core-shell microencapsulated ammonium polyphosphate explosion inhibitor was prepared using in-situ polymerization method. Through experiments on flame suppression and overpressure suppression during explosive combustion, the inhibitory effect of core-shell microencapsulated ammonium polyphosphate explosion suppressant on coal dust explosion was studied, revealing the coupling inhibition mechanism of thermal propagation isolation obstruction effect and group reaction reduction of key atoms. The experimental results show that when 60 wt% core-shell microencapsulated ammonium polyphosphate explosion suppressant is added, the suppression effect on the explosion and combustion of different metamorphic coal is significant, and the flame propagation and pressure rise of coal dust explosion can be basically achieved. By analyzing the substances before and after the explosion through characterization experiments, the inhibitory mechanism of core-shell microencapsulated ammonium polyphosphate explosion suppressant on different metamorphic coal was obtained. Expanding the application field of microcapsule materials provides important methods and theoretical basis for developing core shell microcapsule flame retardant and explosion suppression materials to prevent coal dust explosion disasters.

Multifunctional polylactic acid sensing fabric based on biomass flame retardants for intelligent fire early-warning

Today, building materials emit many hazardous gases in the event of a fire, causing great harm to human health and the environment. Therefore, it is of great significance to develop bio-based flame retardant materials and to realize preventive measures to reduce fires or their damage. In this work, we fabricated a novel multifunctional fire early-warning polylactic acid-based fabric (MFR-PBF) by coating MXene nanosheet, phytic acid @ furfurylamine (PA@FA) and ammonium polyphosphate (APP) via an eco-friendly layer-by-layer assembly method. MFR-PBF showed outstanding flame retardancy including a limiting oxygen index value of 35 % and better char formation capacity. More importantly, MFR-PBF exhibited sensitive fire early-warning capability (∼1 s) and excellent cyclic alarm stability (>15 cycles) due to the excellent semiconductor responsiveness (light and heat) and the significant catalytic char formation effect. Moreover, MFR-PBF is comfortable, flexible and strong enough to sew onto firefighter uniform to detect a variety of human motions, which can be monitored in the internet by using a LoRa emitter and a gateway. In addition, the controllable heating performance rendered MFR-PBF as a potential portable heater. This work provides new insights into the preparation and application of intelligent fire early-warning fabrics in the smart fire protection and Internet of Things.

Nanoclay-reinforced alginate aerogels: preparation and properties.

Flame-retardant materials that are mechanically robust, low cost and non-toxic from green and renewable resources are highly demanded in many fields. In this work, aerogels of alginate extracted from seaweeds were fabricated and reinforced with nanoclay. The nanoclay particles increase the molecular ordering (crystallinity) of the aerogels through physical interactions with alginate molecules. They also served as cross-linkers and flame-retardant additives to improve the mechanical strength, elasticity, thermal stability and flame-retarding properties of the aerogels. Under exposure to a butane flame (750 °C), the aerogels maintained their structural integrity and did not produce drips. An optimal loading of nanoclay which led to the best flame retardancy (non-flammable) of the aerogel was determined. The results of this work demonstrate that alginate-nanoclay composite aerogels can be promisingly used as flame-retardant thermal insulation materials.

GC-MS Analysis of Tris(1-aziridinyl)phosphine Oxide Flame Retardants in Textile Products

Tris(1-aziridinyl)phosphine oxide (APO) used as flame retardant in textile products, such as curtains, carpets, and sleeping clothes, is prohibited in Japan under the "Act on the Control of Household Products Containing Harmful Substances." This study developed a GC-MS-based method to quantify APO more accurately and safely than the current official method. The APO in textile products was extracted with methanol, the extract was replaced with acetone instead of hexane as previously reported, and purified by florisil cartridge column. This cleanup method was instead of the harmful and carcinogenic dichloromethane used for open column to purify the sample in the official method, giving consideration to health of analysts. For accurate and sensitive quantification, deuterated compound, APO-d12, was used as a surrogate standard. The calibration curve displayed linearity within the 0.01-2.0 µg/mL range for APO. The detection limit for APO was 0.008 µg/g with S/N=5, which was 50 times more sensitive than the current detection limit of 0.4 µg/g, enabling the analysis of sufficiently low concentrations. The recoveries in non-treatment cloth and flame-retardant textiles were 73.5-126.6% and relative standard deviations were 3.3-24.6% when 2 µg APO was added to 0.5 g of samples, confirming that it can be analyzed satisfactorily. Thus, the developed method is applicable to textile products of various materials.

Research and development on phase change material-integrated cloth: A review

The application of phase change material (PCM) has shown great potential in the fabrication of PCM-integrated cloth (PCMIC) due to its numerous advantages, including latent heat storage, narrow temperature range, energy storage density, longevity, and compatibility with textile processing. PCMs can lessen the demand for mechanical heating and cooling systems, which can save energy and assist the environment towards sustainability. PCM-integrated cloth provides new opportunities to enhance thermal comfort, energy efficiency, and functionality across a range of applications. The advancement of PCMIC has shown promise in the past decade. This review covers the fundamentals, latest advancements, characterization methods, and advanced applications of PCMIC in detail. Progresses, challenges, and opportunities of versatile applications of PCMIC in space wear, medical textiles, sportswear, bedding, thermoregulating buildings, flame-retardant textiles, automotive textiles, and footwear are critically summarized. Space agencies like NASA, and ESA used PCM-based products for comfortable space exploration while surgical gauges, bandages, and other clinical products incorporated with PCM comfort much in patients. Moreover, sportswear brands like Nike and Adidas utilized PCM in their products for better wearability. Through an analysis of the foundations, current developments, and challenges, this thorough overview is a valuable resource for further innovation and progress in the field of PCM-integrated textiles.

Flame-retardant composite phase change material with silicone resin and melamine phosphate for battery thermal safety

<p>With the prosperity of electric vehicles (EVs), the thermal management of lithium-ion battery (LIB) is crucial for ensuring the safety of drivers on EVs. Composite phase change material (CPCM) with high latent heat has a great promising prospect in battery thermal management systems (BTMS). However, the thermal management efficiency of CPCM is limited due to the leakage, low thermal conductivity and flammability. Herein, the novel multifunctional CPCM with paraffin (PA), epoxy resin (ER), expanded graphite (EG), methyl MQ silicone resin (MQ) and melamine phosphate (MP) (PEE/MQ/MP3) has been prepared, which can achieve well anti-leakage, high flame-retardant and thermal conductivity, enhancing the thermal safety for battery module. The results reveal that PEE/MQ/MP3 with MQ and MP at a ratio of 1:2 can exhibit optimum flame retardant performance. The total heat release peak, smoke production rate, carbon monoxide production and carbon dioxide production are 169 MJ/m<sup>2</sup>, 0.05 m<sup>2</sup>/s, 0.005 g/s and 0.38 g/s, respectively. The battery module with PEE/MQ/MP3 displays excellent thermal management performance, delaying thermal propagation. Even after ten cycles at a 3 C rate, the maximum temperature is controlled below 50 ��C and the maximum temperature difference is maintained with 5 ��C. Besides, the thermal propagation processes of battery modules reveal that PEE/MQ/MP3 can absorb and transfer heat in the first stage timely and quickly, efficiently suppressing the thermal hazard occurrence. Therefore, this study has proposed a multifunctional flame-retardant CPCM as an effective solution to enhance the thermal safety of battery modules, thus ensuring the safety of EV drivers.</p>

Coordination bond cleavage of metal–organic frameworks and application to flame-retardant polymeric materials

The preparation of MOF-based flame retardants derived from coordination bond cleavage is comprehensively reviewed for the first time. Furthermore, the unique advantages and future prospects of cleaved MOFs in the flame retardant field are proposed.

Flame Retardant Material Based on Cellulose Scaffold Mineralized by Calcium Carbonate

Flame Retardant Material Based on Cellulose Scaffold Mineralized by Calcium Carbonate

Facile preparation of sodium alginate based hybrid material and its enhanced flame retardancy: Unravelling the role of silver phosphate

In this study, the sodium alginate/silver phosphate (NaAlg/Ag3PO4) hybrid materials were prepared in-situ, and the composites were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, scanning electron microscopy, and Fourier transform infrared spectrum. To investigate flame-retardant properties of NaAlg/Ag3PO4 and the phosphorus-polymetallic flame-retardant effects, the combustion behavior and flammability of the composites were assessed via the thermogravimetric analysis, limiting oxygen index (LOI) and micro-calorimeter tests (MCC). The results show that the LOI of NaAlg/Ag3PO4 was 52.3%, which was upgraded from flammable material to flame retardant material, compared to 18.5% of NaAlg, and the heat release capacity (HRC) of NaAlg/Ag3PO4 was 37 J/(g·K), which was reduced by 66.7% compared with that of pristine NaAlg, and the fire safety performance was also consistent with the order of thermal stability. By using the thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) and pyrolysis-gas chromatography–mass spectrometry (Py-GC/MS), the flame retarding mechanism of the NaAlg/Ag3PO4 and the role of Ag3PO4 in the material were proposed based on the experimental data.

Si, B-containing dynamic covalent bonds enable excellent flame retardancy and reduced fire hazards for cyanate ester resin.

Cyanate ester (CE) resins are distinguished by excellent dielectric properties in electronic packaging materials but face significant fire risks, with existing strategies often compromising their processability or original properties. Herein, we propose an innovative strategy involving the exchange of dynamic covalent bonds under heat stimuli aimed at forming a continuous and compact char layer to enhance the fire safety of CE resin. Using a straightforward one-pot method, dynamic Si-O and B-O bonds were integrated into a novel hyperbranched polymer (HPSiB), ensuring good compatibility with CE resin while lowering its peak curing temperature by 185 °C for facile processability. The resulting material with 6 wt% HPSiB exhibits a LOI value of 32.8% and UL-94 V0 rating, especially a low total smoke production of 6.7 m2, demonstrating excellent flame retardancy and reduced fire hazards compared to reported Si or B-containing flame-retardant materials. Moreover, its glass transition temperature increased by 35 °C, along with enhanced mechanical properties and an ultra-low dielectric loss of 0.0031 at 10 GHz. These advancements highlight the significant potential of this work in developing high-performance fire-resistant materials.

Functionalizing chitosan-based film with highly sensitive fire response and commendable flame retardancy for intelligent fire-alarm system

Recently, the extensive use of combustible materials has amplified building fire damage, making it essential to incorporate fire-detection devices and flame-retardant materials in building. Herein, the chitosan/gelatin (CG) film and KH2PO4-modified CG (KCG) films were fabricated via an eco-friendly water evaporation method. Impressively, KCG films demonstrate swift response times: 0.5 s at 100 °C and 1.5 s under flame, facilitating prompt alarms during fire incidents. Compared to CG, KCG achieve a 70.4% and 46.2% reduction in peak heat release rate and total heat release respectively. They also offer flexibility, transparency, repeated fire-warning efficacy and superior char formation. With these properties, KCG hold promise for innovative building fire safety solutions like smart fire-alarm wallpaper. Besides, a tailored wireless-based fire-alarm system for KCG further decreases building fire damage. This work mitigates damages arising from building fires work, marking significant leap forward in the use of bio-based materials for fire prevention in architecture.

Eco-friendly phosphorus-free flame-retardant coating for microfiber synthetic leather via alginate-based layer-by-layer technology

The excellent comprehensive properties of microfiber synthetic leathers have led to their wide application in various aspects of our lives. However, the issue of flammability remains a significant challenge that needs to be addressed. Nowadays, the bio-based chemicals used in the flame-retardant materials have extremely grabbed our eyes. Herein, we developed an ecologically friendly flame-retardant microfiber synthetic leather using phosphorus-free layer-by-layer assembly technology (LBL) based on natural polysaccharide alginate (SA) coupled with polyethyleneimine (PEI) and 3-aminopropyltriethoxysilane (APTES). The effect of different LBL coating systems on the flame retardancy of microfiber synthetic leather was investigated. The results demonstrated that the introduction of APTES can completely inhibit the melt-dripping by enhancing char formation through silica elements. Furthermore, the trinary coating system consisting of SA/APTES/PEI exhibited excellent flame retardancy by combining gas-phase action from PEI and condensed-phase function from APTES. This modified microfiber synthetic leather showed a significantly higher limiting oxygen index (LOI) value of 33.0 % with no molten droplet. Additionally, the SA-based coating slightly suppressed the heat release, resulting in a 20 % reduction in total heat release during the combustion test. Overall, this work presents a facile and environmentally-friendly approach for achieving flame-retardant and anti-dripping microfiber synthetic leather.

Optimization strategy for battery thermal management system with phase change materials, aerogel and cold plates

The thermal management system is critical for battery packs in electrical vehicles. Coupling the battery thermal management system (BTMS) with phase change materials (PCMs) and cold plates (CPs) has demonstrated good cooling performance. However, part of the PCMs inside the existing systems doesn't experience phase change, which contribute less to the cooling performance as the weight load increases. In this study, aerogel as the typical lightweight flame retardant materials (FRMs) is adopted to replace the un-melted PCMs to reduce the weight of the system. An optimization strategy for the distribution of PCMs/FRMs in the coupled BTMS is proposed to improve the cooling performance with the system's volume fixed. By locating PCMs on the high-temperature area, an optimized system can be obtained by taking just a few adjusting steps using the developed strategy. After the optimization, the maximum temperature and temperature difference inside the battery pack are reduced by1.0 K and 49% respectively, with the weight of the filling materials among battery cells decreasing by 45%. The proposed strategy shows great potential for efficient optimization of coupled BTMSs with phase change materials and cold plates, which can improve the cooling and lightweight performance of the system simultaneously.