Intumescent Flame Retardant Research Articles

Enhancing flame retardancy, antibacterial activity and UV resistance of polyamide 66 fabric by fully biobased intumescent flame-retardant nanocellulose coating.

Polyamide 66 (PA66) fabric, one of the most common textile materials, presents great fire hazards to human safety and property due to its intrinsic flammability. In this study, fully biobased intumescent flame-retardants (IFRs) composed of cellulose nanocrystals (CNC), tannic acid (TA) and phytic acid (PA) were synthesized and coated onto the surface of the PA66 fabric for improving the flame retardancy, antibacterial and UV resistance. It is found that IFR coating effectively suppressed the droplet and smoke phenomenon of PA66 fabric, and the total smoke production (TSP) and smoke production rate (SPR) values of the fabric were significantly reduced by 71.0% and 36.7%, respectively. The synergistic effect of condensed phase and gas phase flame retardancy could be responsible for the remarkable improvement in the flame-retardant property of the treated PA66 fabric (PA66/IFR). Owing to the TA in the IFR coating, PA66/IFR3 fabric showed obvious antibacterial activity and UV resistance. Furthermore, the PA66/IFR3 fabric retained adequate mechanical properties and maintains satisfactory air permeability. This study provides a green and convenient solution for developing multifunctional PA66 fabrics to meet diversified demands.

Preparation of Nitrogen‐Phosphorus‐Silicon Synergistic Intumescent Flame Retardant and Its Effect on the Flame Retardancy of Waterborne Polyurethane

ABSTRACTWaterborne polyurethane is widely used across various industries, including construction, automotive, leather, and thermal insulation, due to its exceptional properties such as lightweight, thermal insulation, and corrosion resistance. However, its susceptibility to combustion significantly limits its utility, highlighting the critical need for integrating flame retardants into polyurethane formulations. This study focuses on the synthesis of a novel hyperbranched flame retardant, HBNPSi, achieved by manipulating the proportions of 10‐(2′,5′‐dihydroxyphenyl)‐9,10‐dihydro‐9‐oxa‐10‐phospha‐phenanthrene‐10‐oxide (DOPO‐BQ), 1,3,5‐trihydroxyethylcazinone (THC), and isocyanatopropyltrihydroxyethylsilane (IPTS) as the constituent materials. The structural characteristics of the flame retardant were analyzed using infrared spectroscopy, carbon residue analysis, swelling height measurements, and x‐ray spectroscopy (EDS). HBNPSi was then incorporated as a reactive monomer in the pre‐polymerization reaction of aqueous polyurethane to produce a hyperbranched flame‐retardant polyurethane. The flame‐retardant properties were assessed through various tests, including oxygen index, vertical and horizontal combustion, thermo‐red in‐line, and cone calorimetry. Notably, the introduction of DOPO as a flame retardant in a ratio of BQ:THC = 2:1 resulted in an oxygen index of 29% and achieved a V‐0 flame‐retardant rating. Additionally, the decomposition temperature increased from 250°C to 300°C, while the heat release rate (HRR) decreased by 47.8%, total heat release (THR) decreased by 28.2%, and total smoke production (TSP) was reduced by 46.2%.

Synthesis of a new flame retardant and performance study of flame retardant epoxy resin

This paper aims to study a new halogen-free flame-retardant curing agent, 6,6'-(1,5-bis((4-(4-aminobenzyl)phenyl)amino)pentane-1,5-diyl)bis(dibenzo-oxaphosphinine 6-oxide) (DOPO-DMG). The DOPO-DMG was synthesized using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 4,4-Diaminodiphenyl methane (DDM), and glutaric dialdehyde as raw materials in this paper. The chemical structures of DMG and DOPO-DMG were characterized by 1H NMR and FTIR. The results showed that the DOPO -DMG was successfully prepared. The thermal stability, mechanical and flame properties, as well as the morphology of the char layer in composite materials were investigated separately using TG (Thermogravimetric analysis), tensile and Charpy impact tests, LOI (Limiting Oxygen Index) and UL-94 (UL-94 HB flammability standard), and SEM (scanning electron microscope). When IFR (Intumescent Flame Retardants) was added to the EP, the LOI of the composite material improved. DOPO-DMG exhibited excellent flame-retardant properties and produced no toxic fumes when burned in case of fire. Under optimal conditions, it was found that adding DOPO-DMG with a phosphorus content of 2.01% to the epoxy resin resulted in an LOI of 28.8, UL 94 rating of V-0, tensile strength of 39.1 MPa, impact strength of 5.2 KJ/m2 respectively, and a char yield at 800°C of 25.63%.

Fabrication of novel halogen-free flame retardant containing functionalized chitosan from fisheries waste through the sol-gel technology and its fire safety performance in polyurethane resin

Chitosan (CS) derived from fisheries waste, such as shrimp and crab shells, was used to fabricate a bio-based, ecofriendly flame retardant. By reacting the –NH2 groups of CS and the NH2 groups of melamine polyphosphate (MPP) with the NCO groups of polymethylene polyphenyl polyisocyanate (PMPI), a novel intumescent flame retardant, CS-PMPI-MPP, was synthesized. Isophorone diisocyanate (IPDI) was reacted with polyol and aminopropyltriethoxysilane (APTS) to form a polyurethane containing silicon (Si-PU), into which the flame retardant was incorporated to produce a high-polymer composite through the sol-gel technology. The structure, thermal properties, flame retardancy, mechanical properties, toxicity, and char formation of the composites were analyzed. Fourier transform infrared spectroscopy, thermogravimetric analysis, limiting oxygen index, cone calorimeter, UL-94, thermogravimetric analysis with infrared spectroscopy, universal testing machine, scanning electron microscopy, X-ray photoelectron spectroscopy, raman spectroscopy, and smoke density test analyses were performed. The thermogravimetric test results indicated an increase in char yield from 0.5 wt% in pristine polyurethane to 25.9 wt% upon the addition of CS-PMPI-MPP, signifying an enhancement in the thermal stability of pristine polyurethane. According to limiting oxygen index and UL-94 data, the incorporation of CS-PMPI-MPP improved the limiting oxygen index and UL-94 ratings from 18.2 % (Fail) to 26.5 % (V-1), demonstrating the exceptional flame-retardant property of CS-PMPI-MPP within the pristine polyurethane formulation.

A fully bio-based intumescent flame retardant for enhancing the flame retardancy and smoke suppression properties of wood flour polypropylene composites

In this study, a fully bio-based intumescent flame retardant, phytic acid vanillin arginine salt (VR-PA), was designed and synthesized by l-arginine (AR) and vanillin (VA) via a Schiff base reaction, followed by the introduction of phytic acid (PA) using electrostatic ionic interactions. The intumescent flame retardant, VR-PA, was incorporated into wood flour polypropylene composites (WFPP) to enhance their flame retardant and smoke suppression properties. Compared to pure WF, the limiting oxygen index (LOI) of WFPP with 20 wt% VR-PA increased to 28.2 %, while the peak heat release rate and total heat release were reduced by 35.4 % and 20.6 %, respectively. Additionally, the WF with 15 wt% VR-PA exhibited the greatest reduction in total smoke production, with a significant decrease of 42.1 %. The improved flame retardant and smoke suppression performance of the WF is attributed to the free radical trapping effect of VR-PA in the gas phase during the combustion process, as well as the formation of an expanded and continuous carbon layer during in the condensed phase. This study provides a green method to enhance the flame retardancy and smoke suppression of WFPP composites.

Preparation and performance of waterborne polyurethane coatings based on the intumescent flame retardant of boron, phosphorus, and nitrogen

AbstractPNB organic flame retardant was synthesized using 4‐formylphenylboronic acid, 4‐aminophenylthiophenol, 9,10‐dihydro‐9‐oxa‐10‐phos‐phaphenanthrene‐10‐oxide (DOPO), and then introduced into the hydroxyl‐terminated polybutadiene acrylonitrile (HTBN) molecular chain to successfully prepare a macromolecular flame retardant, which was used to prepare flame retardant waterborne polyurethane. The mechanical properties, thermal properties, and flame retardancy of waterborne polyurethane (FR‐WPU) were studied using thermogravimetic analysis (TGA), limiting oxygen index (LOI), scanning electron microscope (SEM), cone calorimeter, and universal testing machine, respectively, and the flame retardant mechanism of macromolecular flame retardants was explored. An LOI value of 29.76% and a UL‐94 V‐0 rating could be realized when the APFBH conjugation is 7.5 wt%, showing a significant improvement of melt dripping behavior and flame retardancy. It indicated that the fire resistance of FR‐WPU remarkably improved and displayed both gas and condensed phase mechanism. As the content of APBDH increased, the tensile strength and the elongation at break of FR‐WPU increased firstly and then decreased.

Study on flame retardant and smoke suppression of EPDM by sepiolite expansion flame retardant system

AbstractA large amount of smoke will be produced during the combustion of ethylene propylene diene monomer(EPDM), which seriously endangers the environment and personal safety. In this study, K‐SEP was obtained by modifying sepiolite with KH550, and two bio‐based flame retardant and smoke suppression systems AEGS and PEGS were prepared by combining ammonium polyphosphate intumescent flame retardant system (AEG) and piperazine pyrophosphate intumescent flame retardant system (PEG), respectively. The flame retardant and smoke suppression properties of AEGS and PEGS on EPDM matrix composites were investigated. The experimental results show that the LOI values of EPDM/AEGS3 and EPDM/PEGS3 composites with 3 phr K‐SEP are 8.1% and 5.5% higher than those of the blank samples without sepiolite. TSP decreased by 26.3% and 14.3% respectively, which proved that sepiolite has important research value in the field of flame retardant and smoke suppression of polymer materials.

In-suit cemented strategy enables intumescent flame retardant transition from hyper-hydrophilic to hydrophobic and aggregation flame retardant effect simultaneously in polypropylene

To meet the stringent requirements of specific high-end manufacturing applications involving flame retardant polypropylene (PP) materials, it's imperative to overcome the inherent superhydrophilicity of intumescent flame retardants (IFR) while simultaneously further enhancing flame retardant efficiency. In addressing this challenge, novel in-situ cemented MVC-IFR microparticles characterized by a microparticle-aggregation effect and hydrophobic structure were successfully synthesized. The micro-aggregated MVC-IFR particles not only bolstered the hydrophobicity and charring flame retardancy of PP composites compared to conventional IFR but also exhibited superior resistance to water erosion. The water contact angle (WCA) of 3MVC-22IFR reached an impressive 159°, whereas the WCA of IFR stood at 0°. Moreover, when MVC-IFR and IFR were incorporated into PP, 3MVC-22IFR/PP displayed a WCA of 108° which was a hydrophobic composite, while 25IFR/PP exhibited a WCA of 81° which was a hydrophilic composite. Notably, the hydrophobic MVC-IFR showcased greater resistance to water exposure than hydrophilic IFR, thereby maintaining its flame retardant efficacy in practical applications. Furthermore, MVC-IFR microparticles with aggregation of acid, carbon, and gas sources, facilitated the charring reactions of different components, thereby enhancing its charring flame retardant effect in PP. Remarkably, 1MVC-24/PP not only attained a UL 94V-0 rating but also achieved a glow wire flammability index (GWFI) of >960 °C, a glow wire ignition temperature (GWIT) of 850 °C, and an LOI value of 28.7 %. In contrast, 25IFR/PP failed to secure a UL 94 rating and exhibited lower GWIT and LOI values. Crucially, the peak heat release rate and total smoke release of 1MVC-24IFR/PP were markedly reduced by 76 % and 41 %, respectively, compared with those of neat PP. In summary, this study presented a novel design concept and rules for flame retardant morphology, to find a way for the development of polyolefin materials boasting both high hydrophobicity and superior flame retardancy.

Double cross-linked biomass aerogels with enhanced mechanical strength and flame retardancy for construction thermal insulation

Biomass aerogels are expected to be a popular material in construction field due to their sustainability, eco-friendliness and excellent thermal insulation properties. In this paper, high modulus biomass aerogels based on the principle of double cross-linking of physics and chemistry were synthesized by freeze-drying technique using gelatin, sodium carboxymethyl cellulose, glutaraldehyde, phytic acid and diatomite as raw materials. The presence of a double cross-linked network structure endowed the prepared aerogels with a low thermal conductivity (0.021–0.029 W·m−1·k−1). The density of only 0.0865 g·cm−3 biomass aerogel exhibited an extrastrong compression modulus of 31.5 MPa, which was superior to common biomass aerogels. Biomass intumescent flame retardant system composed of sodium carboxymethyl cellulose (carbon source), gelatin (gas source) and phytic acid (acid source) was used in combination with diatomite to enhance flame retardancy (limit oxygen index value up to 36.5 %, UL-94 V-0 rating and total smoke production reduced from 0.31 m2 to 0.18 m2) and thermal stability (the residue up to 48.91 %). Remarkably, the modified aerogel showed incredible hydrophobicity (hydrophobic angle of 137°). In summary, the results indicated this study proposed a novel green idea for the preparation of construction thermal insulation materials with a combination of high modulus, flame retardancy and hydrophobicity.

Investigating Intumescent Flame-Retardant Additives in Polyurethane Foam to Improve the Flame Resistance and Sustainability of Aircraft Cabin Materials

Polyurethane (PU) foam has a high flammability and is widely used in aircraft interiors, presenting a significant danger to occupants. This study analysed three composite intumescent flame-retardant (IFR) coatings for flexible PU foam; expandable graphite (EG), ammonium polyphosphate (APP) and alginate (AG). The coatings were prepared in concentrations of 5 wt%, 10 wt%, and 50 wt% with an acrylic binder. The coated samples were characterised using cone calorimetry, SEM, and mechanical testing. The findings showed peak heat release rate, total heat release, and carbon dioxide production from the 10 wt% triple-layer coating (EG:APP:AG) was 52%, 32%, and 58% less than the PU control. The char of the 10 wt% triple-layer sample effectively suppressed smoke release and inhibited the transfer of fuel and gas volatiles. Mechanical testing demonstrated a 3.4 times increase in tensile strength and a 15.4 times increase in compressive strength (50% compression) compared to the control PU with the 10 wt% triple-layer coating. A fire dynamics simulator model was developed that demonstrated large-scale flammability modelling for commercial aircraft. Future work can explore the integration of IFR coatings into computational analysis. These new bio-based coatings produced promising results for aircraft fire safety and flammability performance for PU polymers.

OPTIMIZING THE AMOUNT OF FLAME RETARDANT USED FOR SPRUCE WOOD

The study investigated the effect of the amount of selected retardant coatings produced and used in the Slovak Republic on the fire resistance of spruce wood samples. Experiments were conducted for two different types of flame retardants: intumescent flame retardant (IFR) and inorganic salt-based flame retardant (IS). Based on different amounts of coating applied to spruce wood samples, the important parameters as mass loss, mass loss rate and fire spread rate were determined. The experiment consisted of applying a flame source to the samples at an angle of 45° and monitoring the mass of the samples during the experiment. The findings show that when IFR is used, the protection effect of the wooden samples increases linearly with the amount of coating. However, for the samples on which an IS flame retardant was applied, a higher amount of coating had no effect on increasing the fire resistance of the wood. In this case, the average total mass loss was the same regardless of the amount of coating, yet a significant retardation effect was observed compared to the untreated samples. Samples treated with IFR showed a lower total mass loss and also a significantly lower maximum mass loss rate compared to the samples with applied IS flame retardant.

Tri-source integrated adenosine triphosphate complexed copper ions anchored to boron nitride surfaces for enhancing flame protection of waterborne epoxy coatings

The abundant C, P, and N elements in the structure of adenosine triphosphate (ATP) can act as carbon, acid, and gas sources, and thus can be used as an efficient intumescent flame retardant. Here, a layer of polydopamine (PDA) with polyhydroxyl groups was firstly loaded on the surface of BN to provide a bridging effect for the surface modification of BN. Then, ATP-Cu was immobilized on the BN surface by complexation of ATP with Cu2+, resulting in an efficient inorganic-organic-metal composite flame retardant (BNP@ATP-Cu). This composite flame retardant effectively combined the high barrier effect of BN, the high swelling property of ATP and the catalytic carbon formation activity of Cu2+. The experimental results revealed that the EP loaded with BNP@ATP-Cu showed the lowest backside temperature (171.2 °C), indicating the highest thermal barrier effect. Moreover, BNP@ATP-Cu/EP exhibited the most significant swelling characteristics (22.7 mm, 17.46) and smoke suppression effect (42.8 %). In contrast, the carbon residue of BNP@ATP-Cu/EP (30.8 %) was significantly higher than that of the other coated samples, which was related to the combined effect of BN and ATP-Cu. The above relevant results fully demonstrated the effectiveness of the composite flame retardants in improving the fire resistance of epoxy coatings.

Miscanthus floridulus-based intumescent flame retardant by green self-assembly for fully biological EP composites with commendable flame retardancy, smoke suppression and mechanical properties

The design of fully biological epoxy resin (EP) composites with high performance is highly desirable driven by green and sustainable development due to their renewable and sustainable nature. Herein, an efficient intumescent flame retardant based on Miscanthus floridulus (MF-based IFR) was devised for bio-epoxy composites by a green self-assembly method. The resulting composites with 15 wt% MF-based IFR demonstrated outstanding flame retardancy, effective smoke suppression, and favorable mechanical properties. The enhanced flame retardancy demonstrated the V-0 rating of UL-94 and the 26.4 % of limiting oxygen index (LOI) due to the dual-phase flame-retardant mechanism. Compared to pure EP, the EP composite with 15 wt% MF-based IFR exhibited reductions of 71.90 %, 61.85 %, 55.0 %, and 60.94 % in peak heat release rate (pHRR), total heat release rate (THR), smoke release rate (SPR), and smoke growth rate (TSP), respectively. Additionally, compared to unmodified MF, the composites with 15 wt% MF-based IFR displayed increasing of 3.35 %, 11.26 %, and 10.24 % in tensile, bending, and impact strengths, respectively, attributed to the enhanced interface compatibility. This study provides a straightforward, cost-effective, and efficient strategy for producing fully bio-based epoxy composites with high performance, expanding their potential applications.

Preparation of halogen-free flame retardant curing agent and its application in epoxy resin

9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-N-Aminoethylpiperazine (DOPO-AEP), a phosphorus and nitrogen intumescent flame retardant curing agent was prepared by using acetonitrile as solvent using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and N-aminoethylpiperazine (AEP) as raw materials. The structure of the flame retardant curing agent DOPO-AEP was analyzed Fourier Transform Infrared Spectrometer (FTIR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESI-MS), and the synthesis method of the target product was determined. In addition, the content of char residue was determined by thermogravimetric analyzer, and its thermal properties were comprehensively explored, and based on the obtained results, the curable epoxy resin was selected to prepare DOPO-AEP/EP flame retardant composites. According to the amount of DOPO-AEP added product, different proportions of DOPO-AEP/EP flame retardant composites were prepared, and the actual impact of flame retardant properties and mechanical properties of epoxy resin in different proportions was explored. When the content of DOPO-AEP is 35%, the limiting oxygen index of DOPO-AEP/EP reaches 29.9, which has a significant increase compared with the limiting oxygen index of pure epoxy resin of 19.8, but compared with the content of DOPO-AEP of 30%, the limiting oxygen index of DOPO-AEP/EP is 28.7, and there is no significant increase change. Comprehensive analysis shows that when the component content of DOPO-AEP is 30%, the flame retardant system has a tensile strength of 29.0 MPa, an impact strength of 4.5Kj/m2 and a flexural strength of 73.9 MPa, and its limiting oxygen index is as high as 28.7, and the comprehensive performance of the system is the best. By testing the surface morphology of the flame retardant composites after combustion by SEM, it was found that a dense char layer was formed on the surface of the epoxy resin cured char residue and foamed obviously, indicating that the flame retardant curing performance of DOPO-AEP was good.

Synergistic Effects of Titanium-Based MOFs MIL-125 with Intumescent Flame Retardants in ABS Polymer Composites on Flame Retardancy Study

The intumescent flame retardant (IFR) technique is an alternative to halogen-based flame retardants for reducing fire hazards in polymers. However, IFR has drawbacks like unsatisfactory flame-retardant efficiency and high loading requirements. In this study, MIL-125 (Ti-based metal–organic framework) is added to ABS/IFR composites to improve flame retardancy and reduce smoke emissions. Thermogravimetric analysis (TGA) results indicate that combining ammonium polyphosphate (APP) and expandable graphite (EG) increases charred residue and slows mass loss compared with the original ABS resin. The ABS/IFR/MIL-125 system stabilizes the char layer, serving as a protective shield against combustible gases during combustion. Additionally, MIL-125 enhances performance in microscale combustion calorimetry (MCC) flammability testing. In fire tests (UL-94, limiting oxygen index (LOI), and cone calorimeter), the ABS/IFR/MIL-125 system achieves a UL-94 V0 rating and the highest LOI value of 31.5% ± 0.1%. Peak heat lease rate (PHRR) values in the cone calorimeter are reduced by 72% with 20 wt.% of additives, and smoke production decreases by 53% compared with neat ABS. These results demonstrate the efficient synergistic effects of MIL-125 and IFR additives in improving the formation and stability of the intumescent char layer, thereby protecting ABS from intense burning.

Investigation of MXene@APP/FDS/AgNPs@EG system for preparing multifunctional thermoplastic polyurethane composites with flame retardancy and electromagnetic shielding performance

In order to comply with the requirement of flame retardancy and electromagnetic interference (EMI) shielding for encapsulant applied to electronic devices, multifunctional thermoplastic polyurethane (TPU) composites are prepared with the construction of an intumescent flame retardant (IFR) system comprising internal conductive network. In this work, ammonium polyphosphate wrapped with MXene (MXene@APP) is attained by microencapsulation, and expandible graphite decorated with Ag nanoparticles (AgNPs@EG) is prepared by the reducibility of silk sericin. The IFR system with conductivity is established by the introduction of MXene@APP, AgNPs@EG and furfural-derived Schiff base (FDS). The as-prepared TPU/MXene@APP/FDS/AgNPs@EG composites are able to attain significant elevation in flame retardancy, exhibiting V-0 rating and a LOI value of 33.1 %. Furthermore, TPU composites are integrated with warp-knitted metal mesh (WMM) to fabricate TPU@WMM coated fabric, displaying strengthened electromagnetic interference (EMI) shielding effectiveness (SE) of 37.53 dB within X band. This work provides a potential method for application in encapsulant with flame retardancy and electromagnetic protection.

Effect of Organic–Inorganic Mixed Intumescent Flame Retardants on Fire-Retardant Coatings

Expandable graphite (EG) was modified with a charring agent and organic–inorganic hybridized intumescent flame retardants (MEG) were synthesized. This study uses a cone calorimeter (CCT) and a DaqPRO 5300 radiation heat flow meter (Fourtec, Tel Aviv, Israel) to evaluate the fire-resistant properties influenced by MEG on intumescent fire-retardant coatings. The impact of MEG on the thermal degradation of these coatings was investigated through the use of thermogravimetric analysis (TGA). The results obtained by CCT demonstrated that the incorporation of MEG markedly diminished the heat release rate and total heat release rate of the coating, in addition to enhancing the char residue compared to coatings with only expandable graphite (EG). Furthermore, TGA results demonstrate that adding MEG increases the weight of the char residue at elevated temperatures, suggesting improved thermal stability. Based on these findings, MEG exhibits a synergistic flame-retardant effect when combined with intumescent fire-retardant (IFR) systems. This synergy not only improves the flame-retardant properties of the coatings but also enhances their overall thermal stability, making MEG a promising additive for developing more efficient fire-retardant materials. Thus, MEG-modified coatings offer superior protection against fire hazards, highlighting their potential for practical applications in fire safety.

Synergistic effect of coal gangue on intumescent flame retardants

Abstract In order to improve the flame retardant properties of wood plywood, intumescent flame retardant coatings were prepared using melamine, borate, pentaerythritol and urea as the basic formulations and gangue as a modified additive. The flame retardancy of the samples was characterized using a cone calorimeter, scanning electron microscope, X-ray diffraction and thermogravimetric analysis. In addition, the study investigated the effect of gangue content on the properties of the prepared coatings. The results show that the doping of gangue in intumescent flame retardant coatings can improve the flame retardant effect of the coatings. Specifically, when the mass fraction of gangue was 8 wt%, the exothermic rate, total smoke production and total exothermic amount of the coating were significantly reduced. Moreover, the addition of gangue promoted the formation of a continuous and dense carbon layer structure during the combustion process of the coating, which produced a molten substance that effectively isolated oxygen and heat, thus strengthening the fire-retardant and heat-insulating properties of the coating. The results of this study provide valuable insights into the development of flame retardant coating formulations for wood plywood.

Lignin-Based Carbon Fiber/Epoxy Resin Biocomposites with Excellent Fire Resistance and Mechanical Properties.

Carbon fiber (CF)-reinforced epoxy resin (EP) composites are lightweight materials with excellent comprehensive performance. However, the flammability of EP and the poor interfacial bonding between CF and EP are two key disadvantages that limit their further applications. Here, a kind of water-soluble lignin-based CF sizing agent (ELBEDK) is prepared through hydrophilic modification of enzymatic lignin, which can significantly enhance the interfacial interaction between CF and EP. Additionally, a highly efficient intumescent flame retardant (LMA) is prepared. The EP, enzymatic lignin, LMA and CF sized ELBEDK are compounded to obtain the fire-safety CF reinforced composites (SCF/FEP/L). The flame retardancy of SCF/FEP/L with 7% LMA (SCF/FEP7) reached V-0 rating. Moreover, SCF/FEP/L with 7% LMA and 15% lignin (SCF/FEP7/L15) present an limiting oxygen index (LOI)of 30.2% and V-0 of UL-94. Specifically, the total smoke production and the heat release rate are 47.8% and 46.81% lower than that of SCF/EP, respectively, indicating the improved smoke suppression and flame retardancy. The IFSS and flexural strength of SCF/FEP7/L15 are improved to be 59.4MPa and 511.1MPa, respectively. This study presents a simple approach to fabricate low-cost high performance lignin-based flame retardant CF/EP biocomposites with wide application potential.

Development of a Zr-Based Metal-Organic Framework (UiO-66) for a Cooperative Flame Retardant in the PC/ABS.

Polycarbonate/acrylonitrile butadiene styrene (PC/ABS) blends are widely used as engineering plastic alloys; however, they have a low fire safety level. To improve the flame-retardant property of PC/ABS, a zirconium-based metal-organic framework material (UiO-66) was synthesized with zirconium chloride and terephthalic acid and used as a flame-retardant cooperative agent. Its flame-retardant performance and mode of action in the PC/ABS blends were carefully investigated. The results showed that UiO-66 had good thermal stability and delayed the pyrolysis of the materials, thus significantly enhancing the efficiency of intumescent flame retardants. By compounding 7.0 wt% hexaphenyloxy-cyclotri-phosphazene (HPCTP) with 3.0 wt% UiO-66, the PC/ABS blends reached a limiting oxygen index value of 27.0% and V0 rating in the UL-94 test, showing significantly improved resistance to combustion dripping. In addition, UiO-66 enhanced the smoke and heat suppression characteristics of the intumescent flame-retardant materials. Finally, the flame-retardant mode of action in the blends was indicative of UiO-66 having a cooperative effect on the flame-retardant performance of PC/ABS/HPCTP materials. This work provides good ideas for further development of the flame-retardant ABS/PC.