Flame Retardant Agent Research Articles

Surface-Coated Thermally Expandable Microspheres with a Composite of Polydisperse Graphene Oxide Sheets.

Surface-modified thermally expandable microcapsules (TEMs) hold potential for applications in various fields. In this work, we discussed the possible surface coating mechanism and reported the properties of TEMs coated with polyaniline (PANI) and polydisperse graphene oxide sheets (ionic liquid-graphene oxide hybrid nanomaterial (ILs-GO)). The surface coating of PANI/ ILs-GO increased the corresponding particle size and its distribution range. The morphologies analyzed by scanning electron microscopy indicated that no interfacial gap was observed between the microspheres ink and substrate layer during the substrate application. The thermal properties were determined by thermogravimetric and differential thermal analyses. The addition of ILs-GO to the polyaniline coating significantly improved the thermal expansion and thermal conductivity of the microcapsules. The evaporation of hexane present in the core of TEMs was not prevented by the coating of PANI/ ILs-GO. The printing application of TEMs showed excellent adaptability to various flexible substrates with great 3D appearance. By incorporating a flame retardant agent into TEMs coated by PANI/ILs-GO, finally, these TEMs also demonstrated a great flame retardant ability. We expect that these TEM-coated PANI/ ILs-GO are likely to have the potential to improve the functional properties for various applications.

Facile strategy and mechanism of preparing high performance intrinsic flame retarding foams based on reactive end-capped liquid crystalline all-aromatic polyester without incorporating additional flame retardants

It is still a big challenge to develop high performance polymer foams with outstanding flame retardancy and high thermal stability through a facile strategy. Herein, starting from synthesizing phenylethynyl end-capped all-aromatic liquid crystalline polyester with good processability, a new kind of flame retarding liquid crystalline thermosetting foam (LCTF) was fabricated without adding additional flame retardant and foaming agent. LCTF simultaneously shows outstanding flame retardancy (UL94‒V0 grade, 36.4% of limit oxygen index), excellent smoke suppression and high thermal stability, which are the best values reported so far among intrinsic flame retarding foams. The mechanism of outstanding flame retardancy is revealed by investigating chemical and morphological structures with the aid of three-dimensional reconstruction of morphology. Roles from gas phase and condensed phase are proved to be responsible for unique flame retardancy. The application of LCTF in thermal insulation was also evaluated.

Low concentration of 2,4,6-tribromophenol (TBP) represents a risk to South American silver catfish Ramdia quelen (Quoy and Gaimard, 1824) population

The 2,4,6-tribromophenol (TBP) is an environmental persistent pollutant widely used as flame retardant, antimicrobial and insecticide agent in wood preservation and plastic production. Currently, TBP is found in environmental compartments such as soil, freshwater, groundwater, sewage sludge and domestic dust, but the effects to biota and the risk of exposure to aquatic vertebrates are still scarce. In the present study, Rhamdia quelen fish embryos (8 h post-fertilization - hpf) were exposed to 0.3 and 3.0 μg L−1 of TBP until 96 hpf. Biochemical biomarkers, hatching, survival and larvae/embryo malformations were evaluated after exposure. Additionally, a mathematical model was proposed to evaluate the effects along further generations. The results showed that TBP decreased the survival level but did not cause significant difference in the hatching rates. After 72 and 96 hpf, individuals from the highest tested concentration group showed more severe malformations than individuals from control and the lower concentrations groups. The deformities were concentrated on the embryos facial region where the sensorial structures related to fish behavior are present. The biochemical biomarkers revealed both oxidative stress and neurotoxicity signs after exposure to the contaminant, while the application of the mathematical model showed a decrease of population in both tested TBP concentrations. In conclusion, the current results demonstrated that TBP is toxic to R. quelen embryos and represents a risk to population after early life stage exposure.

Novel flame retardant and antibacterial agent containing MgO NPs, phosphorus, nitrogen and silicon units for functionalise cotton fabrics

During this research, Magnesium oxide (MgO) nanoparticles were synthesised synthesized using Licorice root extract. Synthesized nanoparticles have been characterized using FT-IR, TEM and XRD. The analysis confirmed that the nanoparticles size were ranged from 20 to 40 nm with cubic structure. This nanoparticle was used in the formulation with new synthesised composite containing phosphor, nitrogen and silicon to enhance thermal and flame retardant properties of cotton fabrics. This composite has synthesised via reaction of 3-(hydroxy(phenyl)phosphoryl)propanoic acid and Triethanolamine, and then with triethoxy(3-isocyanatopropyl)silane. Prepared composite was confirmed through NMR and FT-IR measurements. Treated fabric with prepared composite and nanoparticles have been evaluated through elemental analysis, TGA, LOI, antibacterial, mechanical and physical properties. The nanoparticle coated fabrics with prepared composite showed a good degree of microbial resistance and excellent fire proofing rating

New Formulations of Flame-retardant Flexible Polyvinylchloride Composites

The composition of electrical wires and cables is of critical importance in controlling fire risks. In this respect, polyvinylchloride (PVC) composites are extensively used. Yet, PVC composites are multiple systems in which the final properties depend on the nature and size of the reinforcement or flame-retardant agent and the type of lubricant used for their preparation. Thereby, in this study two series of PVC composites, with stearic acid and calcium stearate as lubricants were prepared in parallel, and additivated with various commercial minerals as reinforcement/flame retardant agents, such as calcium carbonate, alumina trihydrate (ATH) and HMH (a mineral of hydromagnesite and huntite). Following the structure (by FT-infrared), thermal behavior (thermal analyses and differential scanning calorimetry) and mechanical properties (dynamic mechanical analyses, tensile strength and elongation at break) of PVC composites, the flame-retardant effect of the selected minerals was investigated by measuring the limiting oxygen index (LOI). Only ATH and HMH-based composites presented higher flame-resistance, relative to the control samples, making them suitable for the proposed application. The contact angle was evaluated for determining the hydrophobicity of composites when using ATH or HMH, to get an opinion about the stability of the materials in moist environments. Finally, SEM was used to determine the homogeneity of PVC samples.

Flammability, Smoke, Mechanical Behaviours and Morphology of Flame Retarded Natural Fibre/Elium® Composite.

The work involves fabrication of natural fibre/Elium® composites using resin infusion technique. The jute fabrics were treated using phosphorus-carbon based flame retardant (FR) agent, a phosphonate solution and graphene nano-platelet (GnP), followed by resin infusion, to produce FR and graphene-based composites. The properties of these composites were compared with those of the Control (jute fabric/Elium®). As obtained from the cone calorimeter and Fourier transform infrared spectroscopy, the peak heat release rate reduced significantly after the FR and GnP treatments of fabrics whereas total smoke release and quantity of carbon monoxide increased with the incorporation of FR. The addition of GnP had almost no effect on carbon monoxide and carbon dioxide yield. Dynamic mechanical analysis demonstrated that coating jute fabrics with GnP particles led to an enhanced glass transition temperature by 14%. Scanning electron microscopy showed fibre pull-out locations in the tensile fracture surface of the laminates after incorporation of both fillers, which resulted in reduced tensile properties.

Effects of two different agents, H3PO4 and NaCl, to increase the flame-retardant properties of cellulose fibers

After flame-retardant treatment by the two different agents, the thermal behaviors of Lyocell fibers are discussed. In this research, H3PO4 and NaCl reduced the degradation rate and increased the char yield of the Lyocell fibers, and also increased the limiting oxygen index with the char yield increased. After treatment, the integral procedure decomposition temperature and the activation energy of Lyocell fibers are significantly increased by various concentration factors. These phenomena were indicated by the dehydration, rearrangement, formation of carbonyl groups, the evolution of carbon monoxide and dioxide, and carbonaceous residue formation. These effects were indicating the slow pathway of flame retardancy for the Lyocell fibers and are attributed to the two different flame-retardant agent treatments.

Novel Thermoset Nanocomposite Intumescent Coating Based on Hydroxyapatite Nanoplates for Fireproofing of Steel Structures

Thermoset nanocomposite intumescent coating swells under the influence of heat forming a thick cohesive insulating barrier; it is one of the most effective ways for fire protection of steel structures. This study reports on the sustainable fabrication of hydroxyapatite (HA) nanoplates as an efficient phosphorous-based flame retardant agent (phosphorous content of 18.5 wt%). Epoxy nanocomposite, based on the synergism between HA particles and advanced intumescent flame retardant agent (commercially known as AP750) was developed. This novel nanocomposite was able to resist a direct flame source at 1700 °C and to self extinguish; it demonstrated an enhanced flammability performance in cone calorimetry with 51% decrease in the peak heat released. Nanocomposite layer of 3 mm thickness was employed for steel substrate protection against direct heat source. The developed intumescent coating was able to protect the steel substrate from heat source at 900 °C. It offered an improved performance, in terms of the coating’s mechanical barrier, and flame resistance properties. HA nanoplates could propose a gas phase effect due to the release of active flame scavengers such as $$ {\text{PO}}_{2}^{ \cdot } $$, PO·, and HPO·. Furthermore, HA could expose a condensed phase effect via the formation of a protective charr layer.

A Novel Cyclic Polysiloxane Linked by Guanidyl Groups Used as Flame Retardant and Antimicrobial Agent on Cotton Fabrics

A novel flame retardant and antibacterial agent, (tetramethylcyclosiloxyl-piperazin) tetra guanidine (GNCTSi) used for cotton fabrics was successfully synthesized. The limiting oxygen index (LOI) value of cotton fabric treated with 250 g/l GNCTSi reached to 30.1 %. The vertical burning test results showed that the char length of the treated cotton fabric was 6.5 cm and have no after-flame and no after-glow. Compared with untreated cotton fabric, the treated cotton fabric showed better flame retardancy and higher residue rate by themogravimetric analysis (TG). The GNCTSi exists on the treated cotton fabric was observed and the residues of cotton fabric after combustion had a homogeneous surface without break by scanning electron microscopy (SEM). The treated cotton fabric showed good antibacterial activity against E. coli and S. aureus and the inhibition zone were 2.5 mm and 2.3 mm, respectively. After repeated washing, the LOI of cotton fabric is still higher than 26 %.

Polyethylene Terephthalate/Carbon Fabric/Polyurethane Foam Sandwich Composites: Flame Retardance and Mechanical Properties

Polyethylene terephthalate (PET) nonwoven fabrics, carbon fabrics (CF), and flexible polyurethane (PU) foams are made into novel sandwich composites using one-step molding. The flame retradance and mechanical properties of the sandwich composites are evaluated, examining the influences of the content of flame retardant agent (20, 30, 40, and 50 wt%) and areal density of PET panels (200, 300, and 400 g/m2). The test results show that the PET/CF/PU sandwich composites are rated flame retardant as V0 and do not generate melts. The failure mode of PET/CF/PU sandwich composites converts from overall fracture to layered fracture as a result of increasing the flame retardant agent. The tensile strength at break of PET/CF/PU sandwich composites with corresponding PET panels is 650 N for 200 g/m, 928 N for 300 g/m, and 1744 N for 400 g/m2, which are 42.63 %, 60.48 %, and 77.85 % greater than those of the PET/PU sandwich composites. Moreover, the bursting strength of PET/CF/PU sandwich composites with corresponding PET panels is 3322 N for 200 g/m2, 3869 N for 300 g/m2, and 4978 N for 400 g/m2, which are 195%, 180%, and 143% greater than those of the PET/PU sandwich composites.

Preparation and property evaluations of zeolite rigid foam composites

AbstractPolyether polyol, isocyanate, and a flame retardant (10 wt%), zeolite (0 wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, and 9 wt%) are used to form the rigid polyurethane (PU) foam, while a nylon nonwoven fabrics (400 g/m2) and a polyester aluminum foil are combined to serve as the panel. The rigid PU foam and the panel are combined to form the rigid foam composites. The cell structure, compressive stress, combustion resistance, thermal stability, thermal conductivity, sound absorption, and electromagnetic shielding effectiveness (EMSE) of the rigid foam composites are evaluated, examining the effects of using flame retardant agent and zeolite. When the zeolite is 5 wt%, the rigid foam composites have an optimal density of 0.172 g/cm3, an average cell size of 0.2131 mm, a maximum compressive stress of 460.03Kpa, an optimal LOI of 28, and optimal EMSE of 40 dB, and the maximum thermal stability, thermal insulation, and sound absorption.

Polyethylene waste carbons with a mesoporous network towards highly efficient supercapacitors

Herein, hierarchical porous carbon derived from polyethylene waste (plastic bags etc.) has been synthesized by ball-milling and carbonization with a flame-retardant agent, basic magnesium carbonate pentahydrate (MCHP:4MgCO3·Mg(OH)2·5H2O). The presence of MCHP not only provides in-situ MgO template during pyrolysis, but also greatly enhances the thermal stability of polyethylene for carbonization. After subsequent NH3 activation, the polyethylene waste derived carbon (PE-HPC-900NH3) shows a high surface area and a unique property of meso-porosity, which contribute to the excellent capacitive performance. Remarkably, the obtained PE-HPC-900NH3 electrode displays a relatively high specific capacitance with excellent cycling stability (about 97.1% of capacitance retention after 10,000 cycles at 2 A g−1). A high energy density of 43 Wh kg−1 can be achieved for the PE-HPC-900NH3 symmetrical supercapacitor at an extremely wide voltage of 4 V in EMIMBF4 due to the high purity and low ratio of O/N. This work provides a promising approach to disposal of waste plastics and opens new applications in various energy fields.

FORMALDEHYDE-FREE AND HALOGEN-FREE FLAME RETARDANT FINISHING ON COTTON FABRIC

This study focuses on the application of environmental-friendly flame retardant (FR) finishing which does not include formaldehyde or halogen based chemicals on cotton fabrics since it has been announced that these kinds of materials have environmental and toxicological hazards. Three different types of FR agents were used in the finishing bath and applied on raw, pre-treated and dyed cotton fabrics, respectively. One of them was the mixture of inorganic and organic salts while the other type was chosen as phosphate structured which have a commercial use in textile industry widely in order to compare the flame retardant effects on cotton. The third type was calcium carbonate based chemical produced in Balıkesir Turkey named Firetex. After finishing treatment of all types of FRs, performance tests as burning tests and color spectrums were carried out beside the characterization tests as SEM and FTIR-ATR analysis. In order to determine the washing durability of the cotton fabrics, each performance test was performed after 5 repeated washing cycle. According to the results, it was observed that both three types of flame retardant agents improved the flame retardant effect of cotton fabrics however the char length of cotton fabric which treated with Firetex was lower than the rest and it was indicated in the study that using natural structured FR could be a new area in green chemistry as a FR textile chemical.

Energy and Water Saving Finishing Method for Producing Durable Flame Retardant Cotton Fabric

This study presents the improvement of durable flame retardant (FR) effect of 100 % cotton fabrics via chemical foaming system which provides energy and water saving significantly, compared to conventional methods. In order to carry out the experiments, dialkylphosphonocarboxylic acid amide based flame retardant agent and auxiliary chemicals were applied on cotton fabrics in a foam formed. Foam parameters such as blow ratios and wet-pick-up ratios were varied and flame retardant properties of foamed cotton fabrics were compared with cotton fabrics treated through pad-dry-cure process in order to determine the performance effect of cotton fabrics in flame retardancy via different finishing methods. After the finishing processes, flame retardant effect of all treated fabrics was examined with vertical burning test method. As durability of flame retardant applied cotton fabrics against washing process is one of the most important subjects that has been tried to be improved with different approaches for a long time, all treated fabrics were washed and dried 50 times, separately. After repeated washing and drying cycles, burning behavior of washed and FR treated fabrics were also tested vertically for determining flame retardancy effect. Beside the vertical burning test, tearing strength test, color spectrums, SEM and SEM- EDX analysis of fabrics were carried out. According to test results, even at the low wet-pick-up ratios, a significant increase was observed in flame retardant effect of cotton fabrics that were treated with FR agents via foam application. Moreover, all treated fabrics were durable against 50 washing and 50 drying processes.

Effect of the flame-retardant 3-hydroxyphenylphosphinyl-propanoic acid on the mechanical, thermal, and flammability properties of poly(ethylene terephthalate) nanofiber mats

The structure, thermal stability, and mechanical properties of electrospun nanofiber mats obtained from poly(ethylene terephthalate) (PET) solutions in trifluoroacetic acid/dichloromethane were evaluated. The electrospun PET nanofibers were characterized by means of attenuated total reflection Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, limiting oxygen index, and tensile testing. PET-3-hydroxyphenylphosphinyl-propanoic acid (HPP) copolymer was used as the flame-retardant (FR) agent to improve the thermal stability and flammability of the nanofiber mats. HPP is a commercial FR for polyesters which was studied from the viewpoint of chemical reactivity and reaction mechanism. To enhance the tensile strength of the nanofiber mats, the nanofibers were collected on high-speed rotating drum. The results showed that the nanofibers were oriented, and their strength was enhanced by increasing the velocity of the collector. The average diameter of electrospun nanofibers was in the range of 110–240 nm, decreasing with the increasing drum speed. Also the mean pore size of the mats decreased significantly with increasing orientation of the nanofibers. The results showed that HPP improved the flame retardancy of PET.

A novel cyclic copolymer containing Si/P/N used as flame retardant and water repellent agent on cotton fabrics

ABSTRACTA novel cyclic‐shaped multifunctional copolymer named poly[tetra(tetramethylcyclosiloxyl‐piperazin)‐phosphinic acid methyl ether] (PNCTSi) was successfully synthesized. Its flame‐retardant and hydrophobicity properties on cotton fabrics were investigated. The limited oxygen index (LOI) value of treated cotton fabrics with PNCTSi was up to 29.8%. By vertical burning test, it was found that the treated cotton fabrics have no after‐flame and no after‐glow. Apparently, more amounts of char were generated and hazardous volatiles distinctly reduce after combustion by thermogravimetric analysis. Besides, Treated cotton fabrics with PNCTSi can give a hydrophobic property, which reach a contact angle of 150°. The surface morphology of treated cotton fabric before and after combustion was analyzed by scanning electron microscopy, after burned, the surface morphology of cotton fiber exhibited more smooth and expanded feature. After washing the cotton fabric for 20 times, the LOI remains at above of 26.0%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47280.

Preparation and evaluation of an eco-friendly, reactive, and phytic acid-based flame retardant for wool

Bio-derived phytic acid exhibits great potential to improve the flame retardancy of textile materials, but it has poor washing durability. In order to address this problem, an efficient, reactive, and phosphorus-containing flame retardant (FR) HPPHBTCA was synthesized using phytic acid, pentaerythritol and 1,2,3,4-butanetetracarboxylic acid, and the chemical structure of HPPHBTCA was characterized. HPPHBTCA was applied to develop FR functional wool fabric, and its FR efficiency and washing durability were evaluated. The wool fabric treated with 0.14 mol/L HPPHBTCA had self-extinguishing performance even after 20 washing cycles during the vertical burning test, presenting good FR ability and resistance to washing. The catalytic char-forming effect of HPPHBTCA contributed to the enhanced FR and smoke suppression properties of wool fabric, and the ester bonds formed between HPPHBTCA and wool fiber resulted in the good washing durability. The HPPHBTCA treatment had a negligible effect on the whiteness, tensile strength and handle of wool fabric. This study offers a novel route to prepare the eco-friendly and durable FR agent using natural and phosphorus-containing compound.

Functionalized graphene with Co-ZIF adsorbed borate ions as an effective flame retardant and smoke suppression agent for epoxy resin.

In order to reduce the fire risk of epoxy resin (EP), functionalized reduced graphene oxide (RGO) with Co-ZIF (zeolitic imidazolate frameworks-67) adsorbed borate ions (ZIF-67/RGO-B) was prepared. The results of transmission electron microscopy (TEM) showed that ZIF-67 was grown on the surface of RGO triumphantly. In addition, the structure of ZIF-67/RGO-B was not significantly changed compared with ZIF-67/RGO. Subsequently, ZIF-67/RGO-B was added into EP by a simple blending method. The combustion results showed that the heat and smoke production of EP composites were obviously reduced. In particular, compared with pure EP, the peak heat release rate (pHRR), the total heat release (THR) and the maximum value of smoke density (Ds,max) of the composite with 2 wt% ZIF-67/RGO-B were reduced by 65.1%, 41.1% and 66.0%, respectively. The main mechanism of ZIF-67/RGO-B for reducing the fire risk of EP was analyzed according to the results of the char analysis. This work provided a new type of modified RGO for reducing the fire hazard of EP.

Effect of Organoclays on Fire Resistance of Siloxane Rubbers

The technological progress constantly raises standards for items operated in rough conditions in order to improve their reliability in a wide range of operating temperatures, fire resistance and sustainability. Researches aimed at discovering flame retardant agents that would help to develop siloxane rubbers with increased fire-resistance are of great scientific interest and have a practical significance. We have studied the effect of aluminium hydroxide on the physical and mechanical properties and fire-resistance of siloxane rubbers. The study has shown that the aluminium hydroxide acts as an effective fire retardant at its content in the rubber over 40 % (wt.), however, it significantly decreases the physical and mechanical properties of the siloxane rubbers and causes difficulties in processing of the rubber mix. The research has shown that the additional introduction of organoclays (5 pts. wt.) improves the fire-resistance of such rubbers, the most effective being montmorillonites modified with alkylbenzyldimethylammonium chloride.

Synergetic enhancement on flame retardancy by melamine phosphate modified lignin in rice husk ash filled P34HB biocomposites

Lignin can be employed as a sustainable functional additive and reinforcement filler for polymers. In this work, melamine phosphate modified lignin (MAP-lignin) was synthesized as a bio-based halogen-free flame-retardant agent. The synergetic effects between MAP-lignin and rice husk ash (RHA) on the thermal stability, dynamic mechanical performance and flame-retardant properties of the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) biocomposites were investigated. The results revealed that MAP-lignin and RHA could significantly increase the char residue and MAP-lignin had a good miscibility with P34HB. The incorporation of MAP-lignin and RHA as stiff fillers could enhance the storage modulus of the P34HB matrix. Moreover, the tensile strength and elongation at break of the P34HB/RHA composite could be improved due to the MAP-lignin could serve as a compatibilizer to improve the interaction between RHA and P34HB. Cone calorimetry data demonstrated that the addition of 30 wt% MAP-lignin and 5 wt% RHA reduced the peak heat release rate (PHRR) and total heat release (THR) of P34HB noticeably by 42.8 and 24.3%, respectively. In addition, the CO2 production rate and CO concentration could be significantly suppressed by the addition of MAP-lignin. The enhanced flame retardancy of P34HB composite should be ascribed to the barrier effect of the increased char residue with compact and intact structure, as well as the released gases from the decomposition of melamine.