Intumescent Effect Research Articles

A multifunctional coating towards superhydrophobicity, flame retardancy and antibacterial performances

To meet the growing demands of multifunctional fabrics in different scenarios that require fire safety, developing flame-retardant coatings with integrated superhydrophobicity and antibacterial properties is imperative. However, how to simultaneously achieve all these features is still a big challenge. Here, a novel multifunctional coating containing polyethyleneimine (PEI), phytic acid (PA), iron ion (Fe3+) and dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (QAS) is constructed by a facile dip-coating strategy. Attributed to the in-situ growth process of the phytic acid metal complex aggregations, the designable hierarchical micro/nano-scale protuberances can be generated. The resultant coating exhibits a good liquid repellency with water contact angles above 155°. Benefiting from the intumescent effect, the coating can produce a dense char layer, and hence to give the coated fabrics a self-extinguishing behavior in the vertical burning test with a limiting oxygen index value of ∼28.5%. Due to the presence of N+ and alkyl chain of QAS, the coating exhibits appreciable antibacterial activity and self-cleaning ability. Additionally, the multifunctional coating can endure more than 20 washing cycles and 100 abrasion cycles without losing its hydrophobicity, flame retardancy and antibacterial properties. The performance and function improvements mainly come from the well arrangements of phosphorus, nitrogen and metal elements. The multifaceted features enable promising applications of such coating in advanced functional textiles, protective clothing, transportation facility, etc.

Fire Intumescent, High-Temperature Resistant, Mechanically Flexible Graphene Oxide Network for Exceptional Fire Shielding and Ultra-Fast Fire Warning

HighlightsGraphene oxide-based hybrid networks were fabricated via introducing multi-amino molecule with triple roles (i.e., cross-linker, fire retardant and reducing agent).The optimized hybrid network with mechanically robust, exceptional intumescent effect and ultra-sensitive fire alarm response (~ 0.6 s) can be used as desirable smart fire alarm sensor materials.Exceptional fire shielding performances, e.g., ~ 60% reduction in peak heat release rate and limiting oxygen index of ~ 36.5%, are achieved, when coated such hybrid network onto combustible polymer foam.

A Dual Active-Passive Coating with Intumescent and Fire-Retardant Properties Based on High Molecular Weight Tannins

In this study, the tannins extracted from the Pinus radiata bark were used to develop an active–passive dual paint scheme with intumescent (IN) and fire-resistant (FR) behaviors. The properties of the coating were observed to depend on the concentration of high-molecular-weight tannins (H-MWT) incorporated into the formulation. At high concentrations (13% w/w), the coating exhibits fire-retardant properties due to the generation of a carbonaceous layer; however, at low concentrations (2.5% w/w), it generates an intumescent effect due to the formation of a carbonaceous foam layer. The dual IN–FR scheme was evaluated against fire by flame advance tests, carbonization index, mass loss, and intumescent effect, and was also compared to a commercial coating. The dual scheme presented good mechanical properties with a pull-off adhesion value of 0.76 MPa and an abrasion index of 54.7% at 1000 cycles, when using a coating with a high solid content (>60%) and the same thickness as those of the commercial coatings. The results of the fire resistance test indicate that the dual scheme generates a protective effect for wood and metal, with an excellent performance that is comparable to that of a commercial intumescent coating.

Self-assembly of phosphonate-metal complex for superhydrophobic and durable flame-retardant polyester–cotton fabrics

Poor washing durability still poses a big challenge to the practical applications of flame-retardant fabrics. Herein, a facile and eco-friendly dip-coating approach is proposed to fabricate durable flame-retardant and superhydrophobic polyester–cotton (PTCO) fabrics. Self-assembled depositions of diethylenetriamine penta(methylene-phosphonic acid) (DTPMP) and ferric ion (Fe3+) were applied on PTCO fabrics through coordination interaction. Owing to the intumescent effect of DTPMP–Fe3+ complexes, DTPMP–Fe3+-coated fabric self-extinguished in the horizontal flame testing. Polydimethylsiloxane (PDMS) was then applied on DTPMP–Fe3+ complexes to impart the flame-retardant PTCO fabrics with superhydrophobicity (water contact angle: 155.6°) and self-cleaning properties. Especially, the washing durability of DTPMP–Fe3+-coated PTCO fabrics was improved by the modification of PDMS. The DT/Fe-8BL@PDMS sample still achieved self-extinguishing in the horizontal flame testing even after 12 laundering cycles. Flame-retardant and superhydrophobic polyester–cotton fabrics are fabricated through the deposition of DTPMP–Fe3+ complexes and further modification of PDMS.

ОПТИМІЗАЦІЯ ЕКСПЛУАТАЦІЙНИХ ВЛАСТИВОСТЕЙ ВОГНЕЗАХИСНОГО ПОЛІМЕРНОГО ІНТУМЕСЦЕНТНОГО ПОКРИТТЯ

Study of the effect of intumescent complex compounds on the basis of aminoderivatives of 2,4,8,10-tetraoxа-3,9-diphosphaspiro[5,5] undecane on the flame retardant properties and water resistance of the ethylene vinyl acetate copolymer in the flame retardant polymer compositions. The structure of intumescent compounds has been confirmed by the methods of elemental analysis and IR spectroscopy, the flame retardant properties of the intumescent systems have been investigated using the method of thermogravimetric analysis. Methods of synthesis of intumescent compounds based on 2,4,8,10-tetraoxа-3,9-diphosphaspiro[5,5]undecane and urea, melamine, dicyandiamidе and mixtures there of have been developed. The synthesized compounds have been shown to enhance the flame retardant properties of the ethylene vinyl acetate copolymer, exhibit an intumescent effect and participate in the construction of a char thermal insulation layer. It has been shown that the water resistance of fire retardant systems with the participation of intumescent complex compounds is much higher than the systems of ammonium polyphosphate / melamine / pentaerythritol composition. The expansion coefficient of intumescent systems containing of intumescent compounds to decrease by 10 - 20% after hydrothermal effects, while, as the expansion coefficient of the traditional intumescent system in the same conditions is reduced by 40%. According to the results of accelerated hydrothermal tests, the stability of polymeric intumescent coatings with the participation of intumescent complex compounds to the action of moisture under conditions of temperature difference was determined. The obtained results indicate the prospect of using the investigated intumescent compounds for the creation of new technologies of intumescent coatings for wood with a long operation life.

Influence of graphene on fire protection of intumescent fire retardant coating for steel structure

Graphene (GR) was used as filler to improve the performance of fire resistance, thermal stability, smoke suppression of waterborne intumescent fire-retardant coating. The influence of graphene (GR) on the properties of the intumescent fire-retardant coating was studied by fire protection test, TGA, SEM and smoke density test. The results showed that the GR can effectively enhanced the performance of fire resistance and thermal stability of the coating. The result of SEM test indicated the coating with GR had excellent intumescent effect and enhanced foam structure. The smoke density test of the coating demonstrated the coating contain GR had excellent performance of smoke suppression.

Effects of a Phosphorus Flame Retardant System on the Mechanical and Fire Behavior of Microcellular ABS.

The present work deals with the study of phosphorus flame retardant microcellular acrylonitrile–butadiene–styrene (ABS) parts and the effects of weight reduction on the fire and mechanical performance. Phosphorus-based flame retardant additives (PFR), aluminum diethylphosphinate and ammonium polyphosphate, were used as a more environmentally friendly alternative to halogenated flame retardants. A 25 wt % of such PFR system was added to the polymer using a co-rotating twin-screw extruder. Subsequently, microcellular parts with 10, 15, and 20% of nominal weight reduction were prepared using a MuCell® injection-molding process. The results indicate that the presence of PFR particles increased the storage modulus and decreased the impact energy determined by means of dynamic-mechanical-thermal analysis and falling weight impact tests respectively. Nevertheless, the reduction of impact energy was found to be lower in ABS/PFR samples than in neat ABS with increasing weight reduction. This effect was attributed to the lower cell sizes and higher cell densities of the microcellular core of ABS/PFR parts. All ABS/PFR foams showed a self-extinguishing behavior under UL-94 burning vertical tests, independently of the weight reduction. Gradual decreases of the second peak of heat release rate and time of combustion with similar intumescent effect were observed with increasing weight reduction under cone calorimeter tests.

Synergistic effect of flame retardants and carbon nanotubes on flame retarding and electromagnetic shielding properties of thermoplastic polyurethane

Thermoplastic polyurethane (TPU)-based composites filled with carbon nanotubes (CNTs) and intumescent flame retardants (IFRs) were fabricated through melt compounding method. For comparison, TPU/IFR and TPU/CNT composites with different filling proportions were prepared, respectively. The results presented that the addition of 1 wt% CNTs and 10 wt% IFRs into TPU could achieve good flame retarding and electromagnetic interference (EMI) shielding properties simultaneously. With regard to flame retardancy, the compounding of CNTs and IFRs effectively suppressed the heat release rate and the UL-94 rating was upgraded to V-0 accompanied with prompt self-extinguishment and disappeared melt-dripping, which was equivalent to incorporate 20 wt% IFRs alone. However, the flame retardancy became deteriorated by loading more CNTs. It was revealed that the addition of CNTs could strengthen the carbonization effect of IFRs, but suppress their intumescent effect. Hence, a right amount of CNT loading was of critical importance to achieve synergistic effect with IFRs. Moreover, compared with the TPU/CNT system, the TPU/IFR/CNT system possessing the same CNT contents had a lower percolation threshold. When 1 wt% CNTs were introduced, the electrical conductivity was increased about two orders of magnitude and EMI shielding effectiveness was doubled in the presence of IFRs. The morphological observation and rheological analysis demonstrated that mixing with IFRs not only improved the dispersion of CNTs through particle collisions, but also benefited for establishing the continuous conductive pathways among the IFR particles. Accordingly, this work provided a promising and facile route to fabricate EMI shielding polymeric composites with excellent flame retardancy.

Flame-retardant, non-irritating and self-healing multilayer films with double-network structure

Flame-retardant, non-irritating, and self-healing double-network films based on host–guest interaction were prepared on paper via layer-by-layer (LbL) assembly. The multilayer films are composed of poly (acrylic acid)-adamantanamine/ammonium polyphosphate-cross-poly (ethylenimine)-β-cyclodextrin (PAA-AD/APP-co-PEI-β-CD). After a mild reaction between APP and PEI-β-CD polymers, PAA-AD and APP-co-PEI-β-CD polymers form the novel double-network films via the host–guest interaction. The novel film can produce a self-healing surface without any initiating agents. Besides, when directly exposed to a flame, such films will generate foam char layers because of the intumescent effect, and will endow the print paper with a self-extinguishing property. The fire protection of the coatings was intensively investigated by a fire protection test, scanning electron microscopy (SEM), compressive strength test, thermogravimetric analysis (TGA), and real-time Fourier transform infrared spectroscopy (FTIR). The fire resistant films were found to have the best fire-protection effect under the low-cost and eco-friendly conditions. The films show potential applications as multifunctional advanced commercial supplies, such as papers, textiles, and wood.

Interlayer growth of borates for highly adhesive graphene coatings with enhanced abrasion resistance, fire-retardant and antibacterial ability

Surface coatings to protect materials from mechanical abrasion, fire and microbial colonization are associated with billion dollars of expenses across broad range of industrial, domestic and defence applications. Currently used protective coatings based on heavy metals, halogenated fire-retardation, and biocide agents have considerable environmental concerns due their toxicity, and lack of effectiveness with limited functionality. In this paper, we present engineering of new multifunctional coating based on graphene composites with the ability to provide “3-in-1” protective properties. These multiple functionalities were created with specially designed graphene composite by growing sodium metaborate (NaBO2·xH2O) crystals into graphene oxide (GO) layer during their reduction, which works synergistically as a surface binder, a flame-retardant additive, and an antibacterial agent. The testing of protective coating performances revealed an outstanding mechanical robustness (ASTM-class 4B), and the reduction of bacterial colonization up to ∼99.92%. The high flame retardant performance of the coated wood, and paper showed non-flammability, strong intumescent effect, and self-extinguishing ability during fire. These protective coatings based on graphene composites due the simplicity of their formulations, scalability, and outstanding performance offer a great potential for their industrial, structural, and environmental applications.

Synthesis of biobased phosphorus-containing flame retardants for epoxy thermosets comparison of additive and reactive approaches

This study presents a two-steps synthesis of novel additive or reactive phosphorus-and-sulfur-containing flame retardants (P-FR) for epoxy thermosets. The first step consists in totally epoxydizing the phloroglucinol. Then, the epoxy functions grafted are partially or totally open by a thiol bearing a phosphonate group to obtain a reactive P-FR and an additive P-FR respectively. The two synthesized P-FR are then incorporated into a DGEBA-IPDA matrix according to an appropriate approach. The impact of these P-FR on glass transition temperature (Tg) is assessed by DSC. Tg values exhibit the plasticizing effect of the additive P-FR and the loss of epoxy functionality due to the incorporation of the reactive P-FR. The thermal properties of the prepared thermosets are characterized by TGA, showing the more efficient action of the reactive P-FR in condensed phase (charring). TGA-FTIR coupling show the presence of phosphorus-containing gases released during the thermal degradation but these P-containing gases have no radical scavenging action in the gas phase. PCFC analyses prove the similar flame retardant properties of the two P-FR by reducing significantly the pHRR, the THR and the EHC. The cone calorimeter tests exhibit a strong intumescent effect of the residue brought by the two P-FR, leading to insulating expanded residue.

A novel UV-curing flame retardant film with significantly intumescent effect

High flammability has always been a major challenge hindering in application of most conventional UV-curable resins. Herein, several intumescent flame-retardant (FR) films characterized with crosslinked network structure were successfully prepared via the combination of tri(acryloyloxyethyl) phosphate (TAEP) with melamine-based acrylate resin (MAAR) by UV-cured method. As compared with sole TAEP- or MAAR-containing films, the mixed films containing TAEP and MAAR exhibited improved flame retardant property. The characterizations of their flammability and char morphologies indicated that the PN-2 with 2/1 mass ratio of TAEP to MAAR had the relatively better flame retardance and could form the intumescent char layer with many thin-walled large bubbles under the compact surface layer. Furthermore, the evolved products for PN-2 with 2/1 mass ratio of TAEP to MAAR during the thermal degradation exhibited much less release than neat TAEP- or MAAR-containing coatings, which implied the increase of the pyrolysis products inside the char layer and thus leaded to the expansion of the intumescent FR films. These results suggest the UV-curing intumescent FR films containing TAEP and MAAR with appropriate ratio possess great flame retardant efficiency that in favor of further application on a substrate, such as fabrics, wood, and plastics.

Intumescent flame-retardant and self-healing superhydrophobic coatings on cotton fabric.

Flame-retardant and self-healing superhydrophobic coatings are fabricated on cotton fabric by a convenient solution-dipping method, which involves the sequential deposition of a trilayer of branched poly(ethylenimine) (bPEI), ammonium polyphosphate (APP), and fluorinated-decyl polyhedral oligomeric silsesquioxane (F-POSS). When directly exposed to flame, such a trilayer coating generates a porous char layer because of its intumescent effect, successfully giving the coated fabric a self-extinguishing property. Furthermore, the F-POSS embedded in cotton fabric and APP/bPEI coating produces a superhydrophobic surface with a self-healing function. The coating can repetitively and autonomically restore the superhydrophobicity when the superhydrophobicity is damaged. The resulting cotton fabric, which is flame-resistant, waterproof, and self-cleaning, can be easily cleaned by simple water rinsing. Thus, the integration of self-healing superhydrophobicity with flame retardancy provides a practical way to resolve the problem of washing durability of the flame-retardant coatings. The flame-retardant and superhydrophobic fabric can endure more than 1000 cycles of abrasion under a pressure of 44.8 kPa without losing its flame retardancy and self-healing superhydrophobicity, showing potential applications as multifunctional advanced textiles.

Chitosan/Phytic Acid Polyelectrolyte Complex: A Green and Renewable Intumescent Flame Retardant System for Ethylene–Vinyl Acetate Copolymer

We describe the preparation and characterization of a green and renewable polyelectrolyte complex (PEC) containing phosphorus, nitrogen and carbon elements, based on the ionic complexation between chitosan and phytic acid. Introduction of this PEC to ethylene–vinyl acetate copolymer (EVA) leads to an improvement of the flame retardancy. As for the EVA/PEC composites with 20.0 wt % of PEC (EVA/20PEC), the char residue at 600 °C is 12 wt % higher than that of the pristine EVA under nitrogen atmosphere. Compared to the pristine EVA, the peak heat release rate and total heat release of EVA/20PEC show 249 W g–1 and 5.6 kJ g–1 decreases, respectively. The char residue of EVA/20PEC is full and compact, demonstrating excellent intumescent effect. Introduction of this PEC also contributes to a slight increase of the Young’s modulus while maintains the excellent ductility. This work provides a new approach for the development of environmentally friendly intumescent flame retardant system.

Influence of nano-boron nitride on anti-aging property of waterborne fire-resistive coatings

The influence of nano-boron nitride (BN) with a multilayered structure on the anti-aging property of fire-resistive coatings was studied. After accelerated weathering for 20 days, the thermal stabilities and fire protection of the coating without nano-BN were significantly decreased, but the coating modified by nano-BN still maintained excellent intumescent effect and fire protection. The results indicated that nano-BN could improve the anti-aging property of the coatings remarkably. FTIR and XPS characterizations suggested that nano-BN with a multilayered structure could prevent the migration behavior of the hydrophilic fire-retardant additives and keep the fixed ratio of those additives in the coating. TGA results demonstrated that nano-BN could effectively enhance the thermal stabilities of the aged coatings and improve the anti-oxidation property of the char layers formed by the coatings. XRD and EDS results proved that the anti-oxidation of the aged coatings under high temperature could be enhanced effectively after adding nano-BN. SEM observations illustrated that nano-BN addition was beneficial to the improvement of the foam structure of the aged coating.

Influences of glass flakes on fire protection and water resistance of waterborne intumescent fire resistive coating for steel structure

Glass flake (GF) was used as a modifier to improve the fire protection and water resistance of waterborne intumescent fire resistive coating. The influences of GF on the properties of the coatings were investigated in detail by using TGA, XRD, X-ray fluorescence spectrometry (XRF), SEM and fire protection test. The TGA results proved that addition of GF could enhance the anti-oxidation of the char layers and increase the residue weights of the coatings. The XRF results indicated that anti-oxidation of the coatings modified by GF was improved. The SEM images demonstrated that addition of GF could improve the foam structure of the coatings. After immersed in water over 600 h, the results showed that the thermal stability and fire protection of the coating without GF were significant decreased, but the coatings modified by GF could still maintain the excellent intumescent effect and fire protection.

Mechanism of intumescence of a polyethylene/calcium carbonate/stearic acid system

In this work, we have investigated the intumescent behaviour of linear low-density polyethylene (LLDPE) containing calcium carbonate (chalk) treated by stearic acid. This system swells during burning and creates a protective layer when exposed to an external heat flux of 50 kW/m 2 in a mass loss calorimeter. This system has been fully characterized by FTIR, XRD, TGA and SEM. The carbonation/decarbonation temperatures, the swelling phenomenon and the effect of the thermal stress on the swelling have been examined. The residue is composed of a smooth surface made of chalk and CaO and a bulk of only chalk. Stearic acid allows a good dispersion of chalk particles into the LLDPE matrix, and contributes to form a cohesive network during burning when the thermal stress is high enough. A governing parameter of the intumescent effect is the particle size, which permits the formation of an insulating and cohesive mineral network during burning.

Development of halogen‐free flame‐retardant thermoplastic elastomer polymer blend

AbstractEthylene‐propylene diene rubber (EPDM) and isotactic polypropylene (iPP) blends have widest industrial applications that require a degree of flame retardancy. Halogen‐free intumescent technology based on phosphorous salt is a significantly advanced approach to make the polymer flame‐retardant. Both ammonium polyphosphate and ethylenediamine phosphate are important intumescent compounds. Their combination with carbonific and spumific agents were studied in binary blends of EPDM/PP. The polymer system was vulcanized online during melt mixing. Intumescent flame‐retardant polymer systems exhibit good flame‐retardancy with optimum comparable physiomechanical, electrical, and fluid resistance properties, including lower smoke emission, which is essential to protect people because the visibility remains unaffected in the event of fire. Pronounced charring and intumescent effect appear to enhance the flame‐retardancy of the polymers. Possible expected intumescent mechanism is proposed based on the nonpyrolysis mechanism for the flame‐retarded polymer and the intumescent components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 407–415, 2004

The application of expandable graphite as a flame retardant and smoke-suppressing additive for ethylene-propylene-diene terpolymer

The influence of expandable graphite on the smoke formation and flammability of ethylene-propylene-diene terpolymer (EPDM) is studied in the present work. Thermogravimetric examinations and nitrous oxide index measurements show that expandable graphite acts as a fire and smoke-suppresant additive predominantly in the condensed phase. Traces of polymer surface temperature against time show that the expanded carbon layer formed in the combustion of expandable graphite produces a heat insulating effect toward the undecomposed bulk. Both smoke suppression and flame inhibition effects can be considered as a consequence of this intumescent effect.

Thermal degradation of pentaerythritol diphosphate, model compound for fire retardant intumescent systems: Part I—Overall thermal degradation

The thermal degradation of pentaerythritol diphosphate (PEDP) has been extensively studied by means of various thermal analytical techniques. It is shown that on heating, PEDP degrades in several successive steps with the formation of a complex mixture of volatile products. The intumescent effect takes place between 280 and 350°C when PEDP melts and undergoes limited weight loss ( c. 15%), with evolution of water as the major volatile product. Extensive degradation of the intumescent char occurs above 500°C with the formation of volatile acidic phosphorus-containing moieties. Further products evolved in the overall thermal degradation of PEDP to 900°C include, hydrocarbons, aldehydes, carbon monoxide and dioxide, methane, hydrogen and phosphine.