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The flammability of various materials used in industry is an important issue in the modern world. This work is devoted to the study of the effect of flame retardants, graphene and DDM-DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-4,4′-diamino-diphenyl methane), on the flammability of glass-fiber-reinforced epoxy resin (GFRER). Samples were made without additives and with additives of fire retardants: graphene and DDM-DOPO in various proportions. To study the flammability of the samples, standard flammability tests were carried out, such as thermogravimetric analysis, the limiting oxygen index (LOI) test, and cone calorimetry. In addition, in order to test the effectiveness of fire retardants under real fire conditions, for the first time, the thermal structure of downward flame propagation over GFRER composites was measured using thin thermocouples. For the first time, the measured thermal structure of the flame was compared with the results of numerical simulations of flame propagation over GFRER.

In order to meet the rapidly growing demand of multi-functional fabric, a super-hydrophobic flame retardant coating for cotton fabric with superior washability and abrasion resistance was prepared. Flame retardant finishing agent P, P-diphenyl-N-(3-(trithoxysilyl) propyl) phospinic amide (DPTES) and hydrophobic finishing agent polydimethylsiloxane @silicon dioxide (PDMS@SiO2) were fixed on the surface of cotton fabric by a simple sol–gel technology in combination with convenient brush-coating process. The coated cotton fabric was capable of self-extinguishing a flame, and the Limiting Oxygen Index (LOI) increased from 18.0% for the control cotton fabric to 26.0% for the treated one at weight gain of 30.3%. The water contact angle (WCA) of C3-PDMS-silica is around 154°, and the slip angle is 8°. In addition, the treated cotton fabric exhibits anti-washing and self-cleaning ability due to the superhydrophobic feature and superior friction resistance. The C3-PDMS-silica sample with excellent char-forming ability, as shown by thermogravimetric analysis (TGA), leading to outstanding flame retardancy. A composite char layer was constituted with char residues and ceramic layer during the combustion of inorganic silicon, which plays the role of heat insulation and flame retardant.

Organic Phase Change Materials (oPCMs) are practical and efficient materials in regulating temperature changes, with broad applications including building material, textiles, and food packaging. However, their flammability poses the main challenge to their widespread applications. This review summarizes various approaches to reduce the flammability of oPCMs including incorporation of flame retardants in shape stabilized PCMs and microencapsulated PCMs, chemical transformations and surface coating, paying particular attentions to the flammability parameters such as limiting oxygen index (LOI), total heat released (THR), peak heat release rate (pHRR) as well as the mechanisms of fire retardancy. Flame-retardant oPCM for practical applications such as plasterboards and fabrics will be highlighted. Further strategies to enhance flame retardant properties of oPCM, such as, incorporation of synergistic flame retardants, chemical modification of PCM (e.g. intrinsically flame-retardant oPCM), have been proposed and commented in the conclusion of this paper.

Herein, three different phosphorus-containing compounds (methyl phosphoryl dichloride, phenyl phosphoryl dichloride and phenyl dichlorophosphate) were reacted with 2-aminobenzothiazole respectively, and a series of synergistic flame retardants with phosphorus, nitrogen and sulfur elements were synthesized, named MPBT, PPBT and POBT respectively. Then, they were added to prepare flame-retardant flexible polyurethane foam (FPUF). Through the analysis of thermal stability, pyrolysis, heat release and smoke release behavior, the influence of different phosphorus-containing structures on the flame-retardant performance of FPUF was studied, and their flame-retardant mechanism was explored in detail. Among them, MPBT had the highest flame retardant efficiency with the same addition amount (10 wt%). The limiting oxygen index (LOI) value of PU/10.0% MPBT reached 22.5 %, and it successfully passed the vertical burning test. Subsequently, the addition amount of MPBT was increased and the best comprehensive performance of flame-retardant FPUF was explored. The results showed that the LOI value of PU/15.0% MPBT was increased to 23.5%. As for PU/15.0% MPBT, the peak heat release rate (PHRR) was 453 KW/m2, which was reduced by 46.64 %; and the flame retardancy index (FRI) value was also increased to 6.88. At the same time, the mechanical properties of flame-retardant FPUF were studied. The tensile strength of PU/15.0% MPBT reached 170 KPa, and the permanent deformation of FPUF/10% MPBT was only 4 %, showing its excellent resilience. The above results show that this phosphorus-containing element hybrid synergistic flame retardant (MPBT) has a very good application prospect in the field of flame-retardant polymer materials.

In this paper, fire resistance of natural fabrics and their composites were experimentally investigated. Special interest was given to use bio based materials such as lignin, chlorophosphates, levulinic acid and cardanol in order to exploit their capability to be utilized as flame retardants. Dopamine hydrochloride was polymerized to polydopamine (PDA) and coated to jute fabric surface. Scanning electron microscope (SEM) and thermogravimetric analysis (TGA)/derivative thermogravimetric (DTG) analyses were performed to examine surface morphology and effect of PDA to degradation behaviour of jute fabrics. Real fire behaviour of non-coated and coated fabrics was observed with torch burn test. UL-94 horizontal flame propagation test was also utilized for composite samples. Limiting oxygen index (LOI) testing that measures the minimum amount of oxygen required for combustion, was carried out for assessing the ability of the composite samples for their ability against flammability. PDA was seamlessly coated on the surface of the jute fabrics with its surface-active feature without damaging the structure of the fabric as observed in the SEM images. With the support of this coating on the fabric surface, the increase of the decomposition temperature of the material can be clearly seen in TGA/DTG analyses and torch burn test showed the increase in the ignition time. UL-94 horizontal testing resulted in decrease in flame propagation rate of PDA coated composite samples. In addition to this, when the mass loss rates after combustion were examined, it was seen that there is a decrease in mass loss in the coated fabrics. Jute fabrics, a type of natural fabric, can be efficiently coated with PDA, and the fire retardant property of the PDA coating on natural fabrics has been clearly demonstrated.

Epoxy nanocomposites coatings filled with hybrid graphene oxide/halloysites (GO/HNT) based intumescent flame-retardant additives (IFR) have been fabricated and investigated in terms of flame retardancy property, thermal stability, and adhesion strength. The dispersion and interaction of the nanofillers with the matrix were characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR). The synergistic flame-retardant effects of ammonium polyphosphate (APP) on flame retardancy properties and thermal stability were investigated by limiting oxygen index (LOI) and thermogravimetric analysis (TGA), respectively. The result shows that the epoxy coating with hybrid GO/HNT based IFR achieve an LOI of 26 % at 1 phr of APP (EGO0.6H0.3APP1). Meanwhile, the maximum mass loss of the EGO0.6H0.3APP1 coating sample is 391.0 °C which showing an increment by 1.3 % compared with neat epoxy coating, demonstrating excellent thermal stability performance. The char residue also suggests, APP played a synergistic flame‐retardant mechanism with a combination of hybrid GO/HNT. The presence of hybrid GO/HNT/IFR considerably enhances adhesion strength between the coating material and metal substrate. The EGO0.6H0.3APP1 showed the maximum LOI value, thermal stability, and adhesion strength among the studied formulations.

Molybdenum disulphide (MoS2) filled polypropylene (PP) composites were prepared using the horizontal ball milling machine followed by injection moulding. The content of MoS2 was varied from 0 to 7.12 vol.%. Scanning electron microscopy showed good dispersion and adhesion of MoS2 with the PP matrix. Experimental density of the composites prepared by horizontal ball milling was close to the theoretical density. Impact energy and Impact toughness were increased by 62.50% to pure PP matrix up to 4.28 vol% MoS2, and then it decreases as it reaches to 7.12 vol% of MoS2. It was found that the addition of 4.28 vol% MoS2 into PP matrix could improve the tensile strength by 11%. Limiting oxygen Index value increases up to 21.3% from 18% (pure PP) which indicates that, composites are fire resistant for their application.

In this study, different amounts of boric acid (BA, 1.25, 2.5, 3.75 and 5.0 wt%) were used to enhance the effectiveness of an intumescent flame retardant (IFR) system composed of ammonium polyphosphate (APP) and pentaerythritol (PER) in polypropylene (PP) including 2 wt% montmorillonite nanoclay (MMT). Meanwhile, metaboric acid and boron oxide which were generated by the decomposition of BA appeared in the melt compounding and the burning processes, respectively. Extensive experimental studies were performed to investigate the effects of BA/boron oxide and MMT combinations on the properties of PP/IFR. The fire resistances of the composites were studied by UL 94, limiting oxygen index (LOI) and cone calorimetry tests. The thermal properties were determined by using thermogravimetric analysis, differential scanning calorimetry and thermal conductivity measurements. In addition, the mechanical properties of the composites were examined. The experimental results revealed that although the additions of 1.25 and 2.5 wt% BA with 2 wt% MMT significantly enhanced thermal and flame resistances of PP composites, 3.75 and 5.0 wt% BA additions generated antagonistic effects and deteriorated the fire resistance of the composites. The sample including 2.5 wt% BA addition achieved the best flame retardancy. The LOI value was increased from 18 to 31% with UL 94 V-0 rating. In addition, the peak heat release rate was reduced from 668.6 to 150.0 kW/m2 and the total heat release value was decreased from 247.9 to 98.4 MJ/m2. In the meantime, the thermal conductivity was increased from 0.22 up to 0.28 W/mK. Furthermore, CO, CO2 and the smoke productions were significantly decreased with respect to PP. NO generation was decreased with BA replacements. At the same time, although there was a slight decrease in the tensile strength, the flexural strength significantly increased with BA and MMT additions.

This manuscript aimed to enhance the mechanical, thermal, and ignition properties of bagasse paper when coated with different coatings synthesized from hydroxyethyl cellulose, 1,3-di-p-toluidine-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane, Talc powder, NaHCO3, cellulose nanocrystal. The effect of these coatings on the mechanical properties was studied by measuring elongation, tensile strength, and burst strength. The stages of degradation and ash residue of the measuring specimens were determined using thermal gravimetric analysis (TGA), behind that, the ignition properties as the flame chamber (UL/94), and limiting oxygen index (LOI) was measured according to standards. These tests proved that 1,3-di-p-toluidine-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane has a direct effect on improving the mechanical characteristics and enhancing the ignition properties of the coated specimens compared to uncoated. In this study the physical, mechanical, thermal, and ignition properties of the bagasse paper sheets were enhanced by easy and low-cost method via synthesis of new coatings based on commercially available chemicals in a reasonable cost.

A novel urea tetramethylene diphosphate dimethyl ammonium diphosphate (UTDDAD) flame retardant was synthesized. The structure of UTDDAD was characterized by NMR. The limiting oxygen index of 30% UT...

A novel reactive flame retardant (FR) based on methionine containing P, N and S flame retardant elements was synthesized for application to cotton fabrics. It was found that the cotton fabrics finished with this flame retardant had excellent flame retardancy and high durability. The limiting oxygen index of the fabric treated with 29% methionine-based FR was as high as 43.9%, and was 37.7% after 50 laundering cycles. Thermogravimetry and thermogravimetry coupled with Fourier transform infrared spectroscopy (FTIR) tests showed that the flame retardant (FR) changed the cellulose decomposition pathway so that a large amount of residue was formed and only a small amount of combustible gases was generated. Scanning electron microscopy showed that the treated fibers were swollen, implying that the FR molecules entered the interior of the fibers, while X-ray diffraction results suggested that the FR have little effect on the cellulose structure. FTIR and X-ray photoelectron spectroscopy results demonstrated that the methionine-based FR contains P, N and S elements, the FR and cellulose formed stable P(= O)–O–C and –COOC– covalent bonds, while microscale combustion calorimetry experiments showed that the total heat release of the treated cotton fibers decreased considerably and the tensile strength of the finished cotton fabrics decreased slightly relative to those of the raw cotton. The free formaldehyde content of the treated cotton was tested, and the results showed that no free formaldehyde was detected in the treated cotton. These results show that the methionine-based FR is a highly effective biologically-based and durable flame retardant.

In this present investigation, the thermal and swelling behaviour of cellulosic fibre reinforced ZrO2-dispersed unsaturated polyester composites is evaluated. Cellulosic fibres (jute and sisal) with chemical treatment and ZrO2 particles are dispersed within an unsaturated polyester matrix with a filler loading of 5–45 wt.% by compression moulding technique. The electronic thermal insulation tester, differential scanning calorimeter, thermo-gravimetric analyser, and limiting oxygen index analyser are used for thermal analysis of the composites. Various solutions with different pH values are used for the investigation of the swelling tendency of the composites. A marked enhancement in thermal and swelling properties is noticed along with the inclusion of fillers within the unsaturated polyester matrix. The fabricated composites displayed optimum results for filler content with 35 wt.% followed by saturation in properties with the dispersion above the same.

Data sourced from literature for wood density (WD) and fire properties for fifteen Nigerian woods were analysed. The fire properties are ignition time (IT), flame propagation rate (FPR), flame duration (FD), afterglow time (AGT), ash formation (AF) and limiting oxygen index (LOI). The aim was to correlate density and fire properties of wood using eigenvalues and eigenvectors. The analysis tool adopted was the statisticalanalysis system (SAS) where principal component and regression analyses were performed. Based on the presented data and analyses, WD was found to relate well with FPR, AGT and LOI with an adjusted R-Square = 83% while the other three parameters: IT, FD and AF constitute random noise. 2.11.0.0 2.11.0.0

In this study, a chitosan-based bioflame retardant additive (referred to as NCS) was prepared by chemically altering CS with silicon dioxide (SiO2) via an ion interchange reaction. The effect of NCS on the thermal stability and mechanical properties of vinyl ester/bamboo fiber (VE/BF) composites was studied. The composites were manufactured by a vacuum-assisted resin transfer molding (VARTM) process. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and X-ray diffraction analysis were used to characterize the NCS. The spectral results revealed a new peak at 1560 cm−1 corresponding to NH3+–−O Si, indicative of bond between CS and SiO2. The SEM, and XRD results showed a diverse morphology (coarse surfaces) and a significant decrease in the intensity of the diffraction patterns, respectively, which further supported the formation of NCS. The heat release rate (HRR) of NCS was observed to decrease significantly by 76%, and the residual char content increased by 47% compared with CS. The flame retardant and thermal behavior of the NCS-VE/BF composites were examined by UL-94 standards, microcalorimetry, and cone calorimetry and thermogravimetric analysis (TGA). The results showed a 32% delay in burning time, a 14% enhancement in the limiting oxygen index (LOI), and an 18% decrease in the peak heat release rate (pHRR) and total heat release rate (THR) after incorporation of NCS in the VE/BF composites. The addition of NCS into the VE/BF composites also resulted in improved the mechanical properties of the composites, including the tensile, flexural and impact properties. Overall, the synthesized NCS proved to be suitable for the fabrication of sustainable flame-retardant natural fiber (NF) composites suitable for substructural parts in engineering applications without deterioration of mechanical properties.

A novel comb-shaped polydimethylsiloxane derivative (DSCFT) was synthesized to endow the flame retardancy and antibacterial properties of cotton fabrics. The main functional group of DSCFT were tested by Fourier-transform infrared spectroscopy. The vertical combustion test and limiting oxygen index (LOI) were used to measure the flame retardancy of the samples. The cotton samples treated with 300 g/L DSCFT acquired LOI value of 28.2% without the after-flame and after-glow. The DSCFT successfully reacted with the cotton fabrics via the process of treatment were shown by scanning electron microscopy and energy dispersive spectrometer observation. Cone calorimetry and thermogravimetric test were used to evaluate the combustion behavior and thermal stability of treated cotton fabrics. The effective heat combustion and total heat release of treated sample were significantly reduced in comparison with blank fabrics, and 42.74% of the char residue was retained at 800 °C. In addition, the antibacterial radios of treated cotton specimens against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were 96.8%, and 97.1% in contrast to untreated samples. The tensile strength of cotton fabrics reduced within acceptable range. Thus DSCFT-treated cotton fabrics had the multiple functions of flame retardancy and antibacterial.

A flame retardant containing phosphorus and nitrogen was synthesized using phytic acid and dicyandiamide, and it was subsequently used to prepare flame-retardant cellulosic paper via an impregnation method. Vertical flame and limiting oxygen index (LOI) were used to evaluate the flame retardancy of the paper. The paper containing modified phytic acid was characterized with Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), X-ray diffraction (XRD), and scanning electron microscopy (SEM). When the concentration of modified phytic acid was 20%, the char length of the treated paper decreased from 12.5 cm to 4.1 cm, the LOI value increased from 19.6% to 41.5%, and the tensile index was only 3.66% lower than that of the control paper. The modified phytic acid was judged to have good flame-retardant effects on the paper.

In this study, a novel bioinspired deep eutectic solvent (DES) was synthesized and functionalized with graphene to prepare G-DES. DES was synthesized in the presence of choline chloride and guanidine, which are biocompatible materials and phosphoric acid, an inexpensive phosphorous source. The flame retardant (FR) efficiency of DES and G-DES coated cotton fabrics was checked by detailed flame tests such as spirit flame test, limiting oxygen index (LOI), and vertical flammability test (VFT). According to the simple flame test result, as-synthesized DES and G-DES coated cotton fabrics withstood continuous flame for 180 and 300 s, respectively, emitting a small amount of smoke. At the same time, the control cotton fabric caught fire and completely burned out within 15 s. Additionally, DES and G-DES coated cotton fabric showed excellent LOI results, 39.5% and 52.5%, respectively. In the case of VFT, DES and G-DES coated cotton fabric produced less char length, such as 8 mm and 2 mm, respectively, indicating an excellent flame retardant property of DES and G-DES. The results revealed that DES could be applied as a transparent FR, which does not change the color of the cotton fabric. Furthermore, G-DES-coated fabric exhibited excellent flame retardancy. Thus, the novel as-synthesized DES and G-DES opens new avenues for the use of bioinspired nanocomposites as FRs for cotton fabrics.

The design of renewable and fully biobased flame retardants (FRs) with high efficiencies and mechanical reinforcement functions for epoxy resin (EP) can greatly advance their potentials to satisfy sustainability. Although some biobased fire retardants have been successfully developed so far, most of existing biobased FRs are often not fully biobased and their syntheses normally involve the use of a large volume of organic solvents in addition to complicated synthesis processes. Herein, we report a facile and green strategy to synthesize fully biobased FR (P-MCC@CS@PA-Na) by surface-functionalizing microcrystalline cellulose (MCC) with chitosan (CS) and sodium phytate (PA-Na) via layer-by-layer assembly in water. The results show that incorporating 15 wt % P-MCC@CS@PA-Na enables EP composite to pass a UL-94 V-1 rating with a limiting oxygen index of 26.2%. Meanwhile, the peak heat release rate, total heat release, peak smoke production release, total smoke production, the fire growth rate, and the fire retardancy index of the EP/15 wt % P-MCC@CS@PA-Na are greatly reduced, indicating a good fire retardance. Notably, the well-designed P-MCC@CS@PA-Na simultaneously strengthens and toughens the EP because of uniform dispersion and a favorable interfacial compatibility between P-MCC@CS@PA-Na and the EP matrix. This work provides a green strategy for the fabrication of highly efficient multifunctional fully biobased FRs for polymers.

The surface of ammonium polyphosphate is modified by layered silicates (kaolinite or functionalized kaolinite). The thermogravimetric analysis data confirm that the layered silicates significantly strengthen the thermal stability of polypropylene (PP) and increase the char residue. Fire safety of PP containing different percentages of modified ammonium polyphosphate and charring–foaming agent is assessed by using limiting oxygen index (LOI) and UL-94 vertical combustion. The addition of layered silicates in polymers can effectively enhance the flame-retardant properties including the enhancements in UL-94 rating and LOI results. The flame-retardant mechanism and model are described based on the results of thermal degradation and char residue analysis.

The more efficient and hydrophobic modificated ammonium polyphosphate (M-APP) and charring agent (M-CA) were prepared based on sol–gel method, and they were used in the preparation of water-resistant and flame-retardant polypropylene (PP) composites. The results showed that the contact angles of M-APP and M-CA were 135.11° and 137.89°, respectively. The flame-retardant and thermal properties of the PP composites were also studied. The results showed that the flame retardancy of PP loaded with 30 mass% intumescent flame retardant (M-APP/M-CA = 3:1) was significantly increased. The limiting oxygen index (LOI) reached 36.8% and passed UL-94 V-0. The peak heat release rate and total heat release of the PP composite decreased from 1011.77 to 134.43 kW·m−2 and 100.58 to 6.86 MJ·m−2, respectively. The peak smoke production rate and total smoke release decreased from 0.13 to 0.0056 m2·s−1 and 1453.09 to 74.82 m2·m−2. The PP composite with M-APP/M-CA = 3:1 also exhibited excellent water resistance, and it could still reach UL-94 V-0 after soaking in 70 ℃ water for 168 h.

An ionic liquid (IL) functionalized graphene oxide (ILGO) containing phosphorus was prepared by GO and ionic liquid ([BMIM]PF6), whose structure was characterized via XRD, FTIR, TG and EDS. Then combined with flame retardants (ammonium polyphosphate-APP and expandable graphite-EG), ILGO acting as synergistic agent was introduced into flexible polyurethane foam (FPUF) to modify its flame retardancy, which was assessed by UL-94, TG, limiting oxygen index (LOI) test and cone calorimeter test (CCT). The results show that the FPUF composites with 0.05 phr ILGO, 7.5phr EG and 7.5phr APP got a LOI of 29.0% and passed the V-0 rating for UL-94, while that for FPUF/EG/APP composites is only 26.7 and not classified at the same loading. The results of CCT showed that ILGO could reduce heat release, smoke suppression and toxic gas production of the FPUF composites. For the FPUF/EG/APP/ILGO composites, the PHRR, THR and TSP were decreased by 24.6%, 32.6% and 18.5%, respectively, compared with the FPUF/EG/APP/GO composites. TG and morphology of char residue reveals that the IL expedite the formation of dense and continuous charring layer and physical isolating effect of GO, which is the inherent reason for the good flame retardancy.

The bimetallic metal–organic framework (CoZn-ZIF) particles of flower bulbs, were grown onto short carbon fibers (SCFs) through an in-situ growth method to prepare CoZn-ZIF@ SCFs. The flame retardant intumescent epoxy resin (EP) composites, were fabricated with CoZn-ZIF@SCFs and ammonium polyphosphate (APP). The limiting oxygen index value of 1wt%CoZn-ZIF@SCFs/4wt%APP/EP composite reached 28.9%, and V-0 rating in UL-94 was attained. Meanwhile, the peak of heat release rate and total heat release was reduced 57.6% and 30.4%, compared with pristine epoxy resin. The analysis of pyrolysis gases and residual char, showed that the improvement in flame retardancy and smoke suppression was due to the catalytic carbonization effect of CoZn-ZIF, along with the strengthening action of the residual layer by SCFs, which led to the generation of more residual char and made it more stable. The improvement in mechanical properties of the flame retardant composite, was due to the reinforcement effects of CoZn-ZIF@SCFs, and its action of interfacial adjustment. This research solved the contradiction between the flame retardancy and mechanical properties of epoxy resin, and proposed a new method to prepare flame-retardant epoxy resin with high performance.

In this article, the flame-retardant epoxy resin (EP) material was prepared by aluminum diethylphosphinate (ADP), melamine (MEL) and pentaerythritol (PER). The data showed that when ADP was only 15%, the limiting oxygen index (LOI) was 29.5%, the material passed UL-94 V-0 rating, and there was no dripping phenomenon. In the thermogravimetric test, the residual amount reached 13.10%. When the total amount of flame retardant added was 10%, the EP-4 compound system and the EP-5 compound system have an excellent flame-retardant effect, indicating that ADP, MEL and PER have good synergistic flame-retardant effect. The average effective heat of combustion (AV-EHC) of the EP-5 complex system was 27.35 MJ kg−1, and the total smoke production (TSP) generated was 24.4 m2. The TSP of EP-5 is the smallest among all samples, and the carbon layer height was up to 32.7 mm. In the presence of PER, not only the total amount of flame retardant is reduced, but also has a good flame-retardant effect, which can promote the sample to be carbonized and effectively inhibit the generation of smoke.

A novel composite based on melamine cyanurate (MC) and aluminum hypophosphite (ALHP) was successfully incorporated into high-impact polystyrene (HIPS). The flame retardancy and combustion properties of the composite were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis as well as by vertical combustion, limiting oxygen index (LOI), and cone calorimetry tests. When the ratio of MC to ALHP was 1:4 (comprising a total of 20 wt.% of the mass of HIPS), the resulting composite (HIPS-5) reached a UL-94 V-0 classification, and the LOI increased from 19.3 to 26.7%. Relative to pure HIPS, the peak heat release rate of HIPS-5 decreased from 807.64 to 180.71 kw m–2, and the total heat release decreased from 93.20 to 60.43 MJ m–2. In addition, the carbon residue of HIPS-5 increased from 6.83 to 21.14%, which was higher than all of the other samples. SEM analysis of the carbon residue after combustion in the cone calorimeter showed that a dense and stable carbon layer was formed on the surface of the HIPS composites. These data indicated that MC and ALHP demonstrated an apparent synergistic role as a flame-retardant system to protect HIPS from further combustion.

Composites from ethylene propylene diene monomer (EPDM) rubber filled with different concentrations 20, 40, and 60 parts per hundred rubber (phr) of aluminum oxide (Al2O3) were prepared. The samples were vulcanized by gamma irradiation at doses (50,100, 150, and 200) kGy. The effects of irradiation doses and Al2O3 contents on the mechanical prorerties (particularly tensile strength, elongation at break % and hardness), physical properties (volume fraction and crosslinking density), thermal properties was studied by thermogravimetric analysis (TGA) and fire resistance was tested using Limiting Oxygen Index (LOI) and rate of burning methods of EPDM and its composites were studied. The results indicated that the improvement of mechanical as well as, physical properties occurred by increasing the concentration of Al2O3 (except the tensile strength values, where the highest values were obtained at concentration 20 phr Al2O3 in the composite irradiated at 100 kGy). The thermal stability and fire retardancy properties of the prepared composites were improved by increasing Al2O3 concentration. Generally, the addition of Al2O3 and gamma irradiation has improved composite’s performance. This is suitable for preparing products of rubber serving in dynamic conditions, with longer expected service life

A synergistic flame retardant (silicon, phosphorus and nitrogen) based on cyclic polysiloxane, ammonium salt of tetramethylcyclosiloxyl-piperazin-phosphinic acid (APCTSi) was successfully prepared and firmly bonded to cotton fabric through a chemical grafting method. The chemical structure of APCTSi was characterized by Fourier transform infrared (FTIR) spectroscopy, 1H and 31P nuclear magnetic resonance (1H NMR and 31P NMR). The scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX) proved that APCTSi successfully adhered to the surface of cotton fabric and the elements on the surface of cotton fabric were evenly distributed. The flame retardant properties were characterized by limiting oxygen index (LOI), vertical burning test, thermogravimetric (TG) analysis and TG-FTIR. The limiting oxygen index (LOI) can reach 30.9% with a char length of 8.7 cm for the weight gain of APCTSi was 16.2%. The combustion behavior was characterized by cone calorimetry test. The peak heat release rate (pHRR) and total heat release (THR) values of treated cotton fabric decreased by 30% and 48% respectively compared to that of pure cotton fabric. All the results proved that the cotton fabric treated by APCTSi had the flame retardant effect of condensed phase (forming stable char layer) and gas phase (releasing nonflammable gases).

A new tris-spiro-(3,4-dioxybenzaldehyde)cyclotriphosphazene [PNCHO] was synthesized from the condensation of hexachlorocyclotriphosphazene with 3,4-dihydroxybenzaldehyde in the presence of strong base. Further reaction of the trialdehydic cyclotriphosphazene based molecules [PNCHO] with three different dianilines (benzidine, 4,4'-methylenedianiline and 4,4′-Sulfonyldianiline) resulted in creation of a new poly(tris-spiro-3,4-dioxbenzene)cyclotriphosphazenes with Schiff-base groups [PNSB1-3]. The structures of [PNCHO] and the polycyclotriphosphazenes-schiff base derivatives were characterized by means of FTIR, 1H, 13C NMR and C.H.N elemental analysis. Differential scanning calorimetery (DSC) revealed a relatively high glass transition temperature (135−175°C) of obtained polymers. Thermal gravimetric analysis (TGA) exhibited their good thermal stability (up to 375oC). The char yield was about 36-42% at 700°C. All polymers were self-extinguishable as the LOI (Limiting Oxygen Index) values were above 26% and this meets with the V-0 and V-1, classification (UL-94). No fumes, soot, or toxic gases emission were observed during burning. The polymers obtained can be used as environmentally friendly, flame-retardant materials.

Currently, the growing field of technology has paved the way for using environmental friendly resources; in particular, plant origin holds ecological concern and renewable aspects. Currently, natural fiber composites have widening attention, thanks to their eco-friendly properties. In the present work, the composite material is reinforced with natural fibers from the bark of banana trees (banana fibers), a material available in Vietnam. Banana fibers are extracted from banana peels, pretreated with NaOH 5%, and then cut to an average length of 30 mm. Banana fiber is reinforced for epoxy resin Epikote 240 with mass percents: 10 wt.%, 15 wt.%, 20 wt.%, and 25 wt.%. The results were evaluated through structural morphology (SEM), mechanical properties, fire resistance, and thermal properties. Experimental results show that the tensile, compressive, and impact strengths of biosynthetic materials up to 20% by weight have increased compared to epoxy neat. Flame retardant and thermal properties are kept stable; 20 wt.% banana fiber gives a limiting oxygen index of 20.8% and satisfactory thermal stability.

This manuscript aimed to enhance the mechanical, ignition properties of polypropylene (PP). To reduce waste pollution of the environment, recycled waste polypropylene (WPP), and waste chicken eggshell (WCES) were used. WCES was used as a bio-filler to form new WPP composites. The effect of the addition of magnesium hydroxide (MOH) and monoammonium phosphate (MAP) on the properties of WPP/WCES composites has been studied. The structure of the composites was characterized by Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The mechanical and dynamic mechanical properties of the composites were investigated. The morphology and the thermal properties of the composites were investigated using a scanning electron microscope (SEM), thermal shrinkage %, and thermal analysis (TGA, DTA). The flame retardancy of the composites was assessed using limiting oxygen index (LOI) and flame chamber (UL/94) according to standard test methods. The results indicated that the 10 phr of the WCES enhanced the tensile strength and flexural strength of WPP/WCES composites by 15 and 8 % compared to the neat WPP composite, respectively. In the case of MAP and MOH fillers, the 5 and 10 phr of MOH enhanced the tensile strength and flexural strength of WPP/WCES composites by 8.3, 25, 51.1, and 65.0 % compared to the WPP/WCES composite containing 30 phr of WCES, respectively. The organic matter of WCES is a natural antioxidant for WPP/WCES composites. The limiting oxygen index (LOI) for a composition containing 30 parts per hundred resin (phr) of WCES is 20.8, slightly greater than that for neat WPP (17.9 %). While the LOI value of WPP composite containing 30 phr of mono-ammonium phosphate is 26 %.

Cotton, the most popular textile fibre used today, suffers from high combustibility and a propensity for microbial growth. In this study, we used oxygen tolerant, visible light-activated free radical polymerisation to functionalise cotton with a biocompatible, fire retardant, antimicrobial coating that provided good fire retardancy when dry, and quickly absorbed water to provide exceptional fire retardancy and thermal insulation in more extreme fire conditions. The functionalised cotton, MF-cotton, had a limiting oxygen index (LOI) of 32% when dry and > 99% when wet. These exceptional fire retardancy results were confirmed by vertical burning tests and cone calorimeter testing. Wet MF-cotton was able to reduce exposure temperature by 140 °C under sustained heat exposure, displaying good thermal insulation. Good antimicrobial activity was demonstrated for MF-cotton against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria with bacterial reductions of 98.1% and 99.998%, respectively, and in vitro testing confirmed its biocompatibility. Finally, MF-cotton had improved tensile properties compared with untreated cotton and maintained its softness and breathability. The coating could have potential applications for fabrics used in hospitals, household soft furnishings, fire blankets, and protective clothing.

Expandable graphite (EG) is a kind of halogen-free flame retardant with high efficiency, but EG produces a lot of smoke when used. In order to reduce the smoke produced by EG flame retardant, layered double hydroxide (LDH)-coated EG was designed and prepared by the hydrothermal method to form composite EG@LDH with core–shell structure and used as flame retardant for polyvinyl alcohol (PVA). When EG@LDH particle content reaches 25%, UL-94 test reaches V-0 rating, limiting oxygen index reaches 33.8%, and the density of smoke is reduced by 75.4% compared with ordinary EG. These results are due to LDH's ability to produce stable oxides during combustion, as well as water vapor that absorbs heat and smoke, protecting the expanded graphite carbon layer from destruction. EG@LDH could suppress the “popcorn effect” of EG, improve the flame-retardant performance, expand the application scope of EG and have a broad application prospect in PVA and resin flame retardant with the characteristics of low cost and environmental protection.

An organic compound melamine phenyl hypophosphite (MPHP), containing phosphorus and nitrogen, was synthesized and characterized. Its flame retardant properties and synergistic flame retardancy with silicon dioxide (SiO2) on polypropylene (PP) was investigated. The limiting oxygen index (LOI) value of PP/30%MPHP reached 31.3%, and UL 94V-0 rating was attained. The LOI value of PP/27%MPHP/3%SiO2 reached 28.7%, and the peak heat release rate (pk-HRR) of PP/27%MPHP/3%SiO2 was 42.3% lower than that of pure PP. In addition, the flame retardant mechanism was investigated using scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray, Fourier transform infrared spectroscopy and Pyrolysis–gas chromatography–mass spectrometry (PY–GC–MS). MPHP/SiO2 had synergistic flame retardant effect, and simultaneously exerted gas phase and condensed phase flame retardant effect. Adding a small amount of SiO2 to PP/MPHP, not only reduced the heat release rate, but also improved the mechanical properties.

The current methods used to impart flame-retardant or fire-resistant properties to flexible polyurethane foams (PUFs) to meet fire safety requirements entail the use of halogenated phosphorus-based...

In this present work, an efficient flame retardant (the ammonium salt of tetrakis(phosphonomethyl)arginine, ATTPMA) was synthesized without organic solvents. Then it was grafted onto bamboo fabric through P–O–C covalent bonds. Thus, the durable flame-retarding bamboo fabric was fabricated successfully. The results of attenuated total reflectance Fourier transformed infrared and scanning electron microscope proved the successful grafting. The flame retardancy was testified by vertical burning and limiting oxygen index (LOI) tests. The char length was only 4.8 cm and the LOI increased to 50.2%. Besides, the value of LOI was still 44.5% after 50 laundering cycles owing to the durability of P–O–C bonds. The char residue in thermogravimetric under N2 reached 46.6% proving the improvement of thermal stability. The result of the cone calorimetry tests showed the peak heat release rate and total heat release decreased 95.0% and 68.3%, respectively. The appearance of dense char layer and the change of gas release proved that the flame retardant acted in both condensed and gaseous phases. In summary, this flame retardant has promising prospects in bamboo fabric.

Phenolic novolac-type epoxy (EPN) resin composites were fabricated by reinforcing with cotton waste (CtW), along with aluminum hydroxide (AH), and boric acid (BA) particles under different filler loadings. For characterization, thermogravimetric analysis, scanning electron microscopy, differential scanning calorimetry, and water sorption tests were performed on the composites. The effects of the CtW, AH, and BA contents on the thermal, flame-retardant, and mechanical properties of the composites were investigated. The triple hybrid additive (CtW:BA:AH) with a ratio of 20:5:10 wt% exhibited the best mechanical and combustion properties. The tensile strengths of this composite and the neat EPN were determined as 95.7 ± 6.92 and 96.6 ± 4.77 MPa, respectively. The T50 temperatures of the BA- and AH-doped composites were higher than that of neat EPN. The highest char percentages were observed in the triple composites, while the lowest were observed in the EPN/CtW composites. The combustion of the triple composite with a CtW:BA:AH ratio of 20:5:10 wt% was spontaneously extinguished in 37 s. Horizontal flammability testing also showed better fire resistance for the CtW/BA/AH composites over their CtW counterparts, with the highest estimated limiting oxygen index of 32.3 obtained for the 20:5:10 wt% composite. The water sorption test results show that the CtW composites had the highest hydrophilicity, especially those with 30 wt% CtW or higher, in the presence of water at room temperature.

Novel porous carbon sheets were developed as green, renewable, cost-effective, and efficient flame retardant material for thermoplastic polymers. Renewable porous graphite sheets were directly obtained from one pot recycling process of agriculture bio-waste sugar beet leaves at low temperature and used as scalable and efficient flame retardant for polystyrene. Thus providing dual benefits to environment for recycling of harmful bio-waste and developing new scalable and efficient flame retardant. The developed renewable flame retardant has specific surface area of 214 m2 g−1 and average pore size of 2.1 nm in addition to natural doping of precious metal residues. The sustainable porous graphite sheets were dispersed well in polymer matrix and their mass loading was altered and optimized giving rise to different polymer composites. Furthermore, different mass loadings of magnesium hydroxide were incorporated with porous graphite sheets in polymer composite. The thermal stability and flammability measurements of developed polymer composites elucidated the significant improvement in fire safety and flame retardancy of developed polystyrene composites. Thus, the reduction in peak heat release rate (PHRR) and total heat release rate (THR) of polymer composites were found to be 62 and 48%, respectively. This is in addition to a significant reduction in rate of burning and improvement in limiting oxygen index (LOI) value achieving reduction and improvement by 84 and 33%, respectively. Additionally, excellent suppression of emission of CO2 and CO gases was recorded (~ 40%). The outstanding flame retardancy and toxic gases suppression effect of developed porous graphite sheets was attributed to its charring capability and porous structure effect in conjunction to natural doping of desirable elemental composition. This study presents a new tool for production of scalable, green, renewable, and cost-effective flame retardant and smoke suppressant materials for thermoplastic polymers.

A novel cyclic Si/P/N flame retardant namely tetra (cyclosiloxyl-trimethoxysilylpropyl spirocyclic pentaerythritol) phosphate (SPPTMS) was successfully synthesized and applied to the finishing of cotton fabrics. The chemical structure of SPPTMS was characterized by Fourier transform infrared spectra (FT–IR) and hydrogen nuclear magnetic resonance (1H NMR). The flame retardant performance of SPPTMS treated cotton fabric was tested by limiting oxygen index (LOI), vertical flammability test, cone calorimetry test (CONE) and thermogravimetric (TG) analysis. The surface structure and element composition of cotton fabric before and after treatment was analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). When SPPTMS concentration is 350 g/L, the LOI of cotton fabric reaches 31.2%. The char residue length is 8.1 cm in the vertical flammability test. Cone calorimetry test results show that the peak heat release rate (pHRR) and total heat release (THR) of treated cotton fabric are reduced to 14.3 kW/m2 and 1.9 MJ/m2, respectively, compared with untreated cotton fabric. Thermogravimetric analysis coupled with Fourier transform infrared analysis (TG–FTIR) results show that the treated cotton fabric releases fewer combustible gases during thermal degradation than untreated cotton fabric. SEM, EDS and TG–FTIR showed that SPPTMS could promote the release of non-combustible gas and the formation of char layer to enhance the flame retardancy of cotton fabric, which indicates that SPPTMS has the flame retardant mechanism of condensed phase and gas phase.