Excellent Fire Retardant Properties Research Articles

Elevated temperature and performance behaviour of rice straw as waste bio-mass based foamed gypsum hollow blocks

The present study explores mechanical, thermal, acoustic, and fire performance evaluation of locally available rice straw as waste bio-mass in foamed gypsum hollow blocks. Two-core hollow gypsum blocks with various agro-waste compositions have been studied in detail and presented. Aluminum sulphate and potassium alum in 1:1 ratio are used as foaming agents in gypsum blocks. The density of two-core hollow blocks varies from 1070 to 730 kg/m3 for 0–15 wt% rice straw addition. The compressive strength of solid cubes and two-core hollow blocks lies in the range of 4.6-1.4 MPa and 2.2–1.1 MPa respectively. Whereas, the thermal conductivity lies between 0.15 and 0.07 W/m.K. exhibiting excellent thermal insulation. The sound transmission class (STC) of straw based foamed gypsum varies over the range of 23 to 20 dB for 20 mm thick with 0–15 wt% agro-waste added samples. The 5 wt% foamed rice straw gypsum sample has shown resistance to the surface spread of flame and the wallette unit of 600 mm × 600 mm has 70.5 kN of load carrying capacity at 800 °C. The foamed agro-waste-based hollow gypsum blocks may be used as a potential building material for non-load bearing wall application owing to its high thermal insulation, moderate acoustic and excellent fire retardant properties.

Fire-Retardant Property of Hexasubstituted Cyclotriphosphazene Derivatives with Schiff Base Linking Unit Applied as an Additives in Polyurethane Coating for Wood Fabrication.

A series of new hexasubstituted cyclotriphosphaze derivatives containing Schiff base linkages were successfully synthesized and characterized. The series contains different terminal substituents of pentyl and tetradecyl. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and carbon, hydrogen, and nitrogen (CHN) elemental analysis were used to characterize the intermediates and final compounds, while the thermal stability of the final compounds is evaluated with a thermogravimetric analysis (TGA) test. The final compounds are physically added to the polyurethane coating formulation and then applied to the wood panel using a brush and the compound’s fire-retardant properties are evaluated using the limiting oxygen index (LOI) test. In this research, compound 3b showed good thermal stability compared to compound 3a. In terms of LOI results, polyurethane with an LOI value of 21.90% was employed as a matrix for wood coating and the value increased to 24.90% when this polyurethane is incorporated with 1 wt.% of the compound 3b. The increase in the LOI value indicates that the wood coating containing hexasubstituted cyclotriphosphazene compounds exhibits excellent fire-retardant properties as additives.

Rice-Husk-Ash-Based Geopolymer Coating: Fire-Retardant, Optimize Composition, Microstructural, Thermal and Element Characteristics Analysis.

Geopolymer using aluminosilicate sources, such as fly ash, metakaolin and blast furnace slag, possessed excellent fire-retardant properties. However, research on the fire-retardant properties and thermal properties of geopolymer coating using rice husk ash (RHA) is rather limited. Additionally, the approach adopted in past studies on geopolymer coating was the less efficient one-factor-at-a-time (OFAT). A better approach is to employ statistical analysis and a regression coefficient model (mathematical model) in understanding the optimum value and significant effect of factors on fire-retardant and thermal properties of the geopolymer coating. This study aims to elucidate the significance of rice husk ash/activated alkaline solution (RHA/AA) ratio and NaOH concentration on the fire-retardant and thermal properties of RHA-based geopolymer coating, determine the optimum composition and examine the microstructure and element characteristics of the RHA-based geopolymer coating. The factors chosen for this study were the RHA/AA ratio and the NaOH concentration. Rice husk was burnt at a temperature of approximately 600 °C for 24 h to produce RHA. The response surface methodology (RSM) was used to design the experiments and conduct the analyses. Fire-retardant tests and thermal and element characteristics analysis (TGA, XRD, DSC and CTE) were conducted. The microstructure of the geopolymer samples was investigated by using a scanning electron microscope (SEM). The results showed that the RHA/AA ratio had the strongest effect on the temperature at equilibrium (TAE) and time taken to reach 300 °C (TT300). For the optimization process using RSM, the optimum value for TAE and TT300 could be attained when the RHA/AA ratio and NaOH concentration were 0.30 and 6 M, respectively. SEM micrographs of good fire-resistance properties showed a glassy appearance, and the surface coating changed into a dense geopolymer gel covered with thin needles when fired. It showed high insulating capacity and low thermal expansion; it had minimal mismatch with the substrate, and the coating had no evidence of crack formation and had a low dehydration rate. Using RHA as an aluminosilicate source has proven to be a promising alternative. Using it as coating materials can potentially improve fire safety in the construction of residential and commercial buildings.

Rice Husk Ash/Silicone Rubber-Based Binary Blended Geopolymer Coating Composite: Fire Retardant, Moisture Absorption, Optimize Composition, and Microstructural Analysis.

Geopolymer coating using rice husk ash (RHA) as the aluminosilicate source has shown excellent fire retardant properties. However, incorporation of rice husk ash into the geopolymer matrix increased water absorption properties of the polymer composite. As such, silicone rubber (SiR) was introduced to improve the moisture absorption and fire retardant properties of the composite. Additionally, the less efficient one-factor-at-a-time (OFAT) approach was conventionally used in past studies on the RHA-based geopolymer composite. In understanding the optimum value and significant effect of factors on the fire retardant and moisture absorption properties of the binary blended geopolymer coating composite, the use of statistical analysis and regression coefficient model (mathematical model) was considered essential. The objectives of this study are to identify the significant effect of factors on moisture absorption and fire retardant properties, to determine the optimum composition, and to study the microstructure of the rice husk ash/silicone rubber (RHA/SiR)-based binary blended geopolymer coating composite. The RHA/AA and SiR/Ge ratios were chosen as factors, and the response surface methodology (RSM) was employed to design experiments and conduct analyses. Fire retardant and moisture absorption tests were conducted. A scanning electron microscope (SEM) was used to observe the microstructure of geopolymer samples. The RHA/alkaline activator (AA) and SiR/Ge ratios were shown to have a significant effect on the responses (temperature at equilibrium and moisture absorption). The high ratio of RHA/AA and SiR/Ge resulted in a lower temperature at equilibrium (TAE) below 200°C and at moisture absorption below 16%. The optimum formulation for the geopolymer coating composite can be achieved when the RHA/AA ratio, SiR/Ge ratio, and sodium hydroxide concentration are set at 0.85, 0.70, and 14 M, respectively. SEM micrographs of samples with good fire retardant properties showed that the char residue of the geopolymer composite coating, which is a layer of excess silicone rubber, is porous and continuous, thus providing a shielding effect for the layer of geopolymer underneath. The sample with good moisture absorption showed the formation of a thin outer layer of silicone rubber without any cracks. The unreacted SiR formed a thin layer beneath the geopolymer composite matrix providing a good moisture barrier.

Excellent Fire Retardant Properties of CNF/VMT Based LBL Coatings Deposited on Polypropylene and Wood-Ply.

In this report, layer by layer (LBL) fire retardant coatings were produced on wood ply and Polypropylene Homopolymer/Flax fiber composites. FE-SEM and EDAX analysis was carried out to analyze the surface morphology, thickness, growth rate and elemental composition of the samples. Coatings with a high degree of uniformity were formed on Polypropylene composite (PP/flax), while coatings with highest thickness were obtained on wood ply (wood). FTIR and Raman spectroscopy were further used for the molecular identifications of the coatings, which confirmed the maximum deposition of the solution components on the wood substrate. A physiochemical analysis and model was proposed to explain the forces of adhesion between the substrate and solution molecules. Fire protection and thermal properties were studied using TGA and UL-94 tests. It was explored, that the degradation of the coated substrates was highly protected by the coatings as follows: wood > PP/flax > PP. From the UL-94 test, it was further discovered that more than 83% of the coated wood substrate was protected from burning, compared to the 0% of the uncoated substrate. The flammability resistance of the samples was ranked as wood > PP/flax > PP.

In-situ phosphine oxide physical networks: A facile strategy to achieve durable flame retardant and antimicrobial treatments of cellulose

• Cotton cellulose was modified via in situ phosphine oxide macromolecules. • Phosphorus monomer was crosslinked with amine via Michael addition reaction. • Excellent flame retardancy and durability to 50 laundry cycles was achieved. • Hydrophilicity and comfort properties of the treated fabrics were enhanced. • Antimicrobial property was achieved via in situ silver nano particle treatment. A facile methodology to durably modify cellulose fibers by forming in-situ phosphine oxide macromolecular physical networks is developed in this work. Such networks were formed by treating the cellulose fibers with a mixture of Michael adducts [trivinyl phosphine oxide (TVPO) and cyclic amines (piperazine and 2,4,6-tri(piperazine-1-yl)-1,3,5-triazine)] followed by a click crosslinking reaction initiated by dry heat, microwave, or steaming process. The in-situ phosphine oxide network is integrated within the cellulose fibers to produce a durable treatment against laundering. NMR and SEM analysis of the treated fibers verified the in-situ formation of phosphine oxide macromolecules in the bulk of cellulose fiber. The treatment was homogenous and achieved an outstanding phosphorus (P) retention (>95%) after even 50 laundry cycles. The treated cotton exhibited excellent fire retardant properties with a limiting oxygen index value >27% and passed the Swiss vertical flammability test at 2 wt% P. Analysis of evolved gasses during thermal decomposition of treated cellulose supported both the condensed and gas phases mechanism. The flame retardant treatment was further adapted to include antimicrobial properties by in-situ formation of silver nanoparticles within the cellulose fibers using a single-step process to demonstrate the versatility of this novel treatment methodology. The treated fabric exhibited excellent antimicrobial as well as flame retardant properties and was also durable to 50 laundry cycles. Contact angle measurements and moisture management test confirmed the excellent comfort behavior of the treated cellulose fabric.

Phosphine Oxide Containing Poly(pyridinium salt)s as Fire Retardant Materials.

Six new rugged, high-temperature tolerant phosphine oxide-containing poly(4,4′-(p-phenylene)-bis(2,6-diphenylpyridinium)) polymers P-1, P-2, P-3, P-4, P-5, and P-6 are synthesized, characterized, and evaluated. Synthesis results in high yield and purity, as confirmed by elemental, proton (1H), and carbon 13 (13C) nuclear magnetic resonance (NMR) spectra analyses. High glass transition temperatures (Tg > 230 °C) and high char yields (>50% at 700 °C) are determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. These new ionic polymers exhibit excellent processability, thin-film forming, high-temperature resistance, fire-resistance and retardation, coating, adhesion, mechanical and tensile strength, and n-type (electron transport) properties. The incorporation of phosphine oxide and bis(phenylpyridinium) moieties in the polymer backbones leads to high glass transition temperatures and excellent fire retardant properties, as determined by microcalorimetry measurements. The use of organic counterions allows these ionic polymers to be easily processable from several common organic solvents. A large variety of these polymers can be synthesized by utilizing structural variants of the bispyrylium salt, phosphine oxide containing diamine, and the counterion in a combinatorial fashion. These results make them very attractive for a number of applications, including as coating and structural component materials for automobiles, aircrafts, power and propulsion systems, firefighter garments, printed circuit boards, cabinets and housings for electronic and electrical components, construction materials, mattresses, carpets, upholstery and furniture, and paper-thin coatings for protecting important paper documents.

Synthesis of Carbon-Nitrogen-Phosphorous Materials with an Unprecedented High Amount of Phosphorous toward an Efficient Fire-Retardant Material.

Phosphorus incorporation into carbon can greatly modify its chemical, electronic, and thermal stability properties. To date this has been limited to low levels of phosphorus. Now a simple, large-scale synthesis of carbon-nitrogen-phosphorus (CNP) materials is reported with tunable elemental composition, leading to excellent thermal stability to oxidation and fire-retardant properties. The synthesis consists of using monomers that are liquid at high temperatures as the reaction precursors. The molten-state stage leads to good monomer miscibility and enhanced reactivity at high temperatures and formation of CNP materials with up to 32 wt % phosphorus incorporation. The CNP composition and fire-retardant properties can be tuned by modifying the starting monomers ratio and the final calcination temperature. The CNP materials demonstrate great resistance to oxidation and excellent fire-retardant properties, with up to 90 % of the materials preserved upon heating to 800 °C in air.

Magnesium hydroxide nanodispersion for polypropylene nanocomposites with high transparency and excellent fire-retardant properties

Cooperation of the inorganic nanoparticles to optical polymer matrices can combine the advantages of inorganic and organic optical materials. However, because the nanoparticles are apt to aggregate, it is difficult to maintain the transparency of optical polymer. In this paper, we successfully prepare the transparent polypropylene/magnesium hydroxide (PP/MH) nanocomposites with excellent fire-retardant properties by the melt extrusion process. The MH nanosheets are homogenously dispersed in the PP matrix, which avoids the nanocomposites becoming opaque due to Rayleigh scattering caused by the aggregation of nanoparticles. The PP/MH nanocomposite samples with thickness of 4 mm can keep good transparency even at high MH contents and the flame-retardant performance of nanocomposites is improved obviously by MH. The limiting oxygen index (LOI) of PP/MH nanocomposite with 100 phr MH increases from 19.3 for pure PP to 29.1. In the cone calorimeter test, the peak of heat release rate (PHRR) is obviously decreased by 72% compared to pure PP. A uniform and continuous residue layer for the PP/MH nanocomposite is formed during burning, which acts as a shield for the transfer of flame gases and heat. These results indicate that the nanoparticles can be dispersed well in thermoplastic matrices to obtain high performance nanocomposites, which provides a good foundation to manufacture functional transparent polymer-based nanocomposites by the melt-extrusion process.

Fire Retardancy of $${{\rm Cloisite}^{\textregistered}}$$ Cloisite ® 20 Organoclay Modified Dehydrated Castor Oil-Based Alkyd Resin

The effect of \({{\rm Cloisite}^{\textregistered}}\) 20 organoclay content on fire retardancy, mechanical and chemical properties of dried films of halogen-free alkyd resins synthesized from \({{\rm Cloisite}^{\textregistered}}\) 20 organoclay and dehydrated castor oil (DCO) were investigated. Structural elucidation of the raw and the fire-retardant resins was confirmed through Fourier transform infrared spectroscopy instrumental techniques. The DCO modified alkyd resin macromolecule was synthesized through alcoholysis–esterification interface using glycerol, phthalic and maleic anhydride. Eight samples of fire-retardant resin were produced. Samples I, II, III, IV, V and VI contain 0, 2, 4, 6, 8 and 10 % by mass of \({{\rm Cloisite}^{\textregistered}}\) 20 organoclay, respectively. Samples VII and VIII contain 4 % of weight of Cloisite 20 with 100 % PA and 3:1 ratio of phthalic anhydride and maleic anhydride, respectively. The fire retardancy was evaluated using Westgate vertical match test. It was found that fire retardancy increases with increases in \({{\rm Cloisite}^{\textregistered}}\) 20 contents without any noticeable effect on chemical resistance, but certain drawbacks with adhesive and gloss properties were observed. The best result was observed with sample IV which contains 6 % by weight of \({{\rm Cloisite}^{\textregistered}}\) 20 and showed excellent fire-retardant properties with adhesion, gloss and hardness properties of 5B, 80 and 1.8 Kg, respectively. The infrared (IR) spectra band at 1035, 921, 792, 683 and 556 cm−1 of Si–O–Si and O–Si–O stretching confirms the successful grafting of the organomodifier.

Effect of manganese and cobalt ions on flame retardancy and thermal degradation of bio-based alginate films

Bio-based cobalt alginate and manganese alginate films were prepared by a facile ionic exchange and casting approach. Their flame retardancy, thermal degradation, and pyrolysis properties were investigated by vertical burning (UL-94), limiting oxygen index (LOI), thermogravimetric analysis, microscale combustion calorimetry (MCC), thermogravimetric analyzer coupled with Fourier transform infrared analysis (TG–FTIR), and pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS). It showed that cobalt alginate film had much higher LOI value (45.0 %) than those of manganese alginate film (30.7 %) and sodium alginate film (24.5 %). Moreover, cobalt alginate film passed UL-94 V-0 rating, while manganese alginate and sodium alginate films showed no rating. Importantly, peak of heat release rate of cobalt alginate and manganese alginate in MCC test was much lower than that of sodium alginate, suggesting that the addition of cobalt ion and manganese ion decreases the release of combustible gases. TG–FTIR and Py–GC–MS results indicated that cobalt alginate and manganese alginate produced much less gaseous products than that of sodium alginate. Finally, a possible thermal degradation mechanism of cobalt alginate and manganese alginate had been proposed. The results provided useful information for understanding flame-retardant mechanism of alginate as well as for designing bio-based materials with excellent fire-retardant properties.

Enhanced fire retardant properties of glass-fiber reinforced Polyamide 6,6 by combining bulk and surface treatments: Toward a better understanding of the fire-retardant mechanism

Polyamide 6,6 (PA6,6) is usually fire retarded in bulk, using aluminum diethylphosphinate (AlPi). In one of our recent papers, it was shown that good fire-retardant properties (e.g. V0 at the UL94 test) could also be achieved by applying an intumescent varnish on the PA6,6 surface. Excellent fire-retardant properties were even obtained combining 5% of AlPi in the bulk with an intumescent coating applied on the polymer surface. The Glow Wire Flammability Index (GWFI) test was validated at 960 °C whereas it was only validated at 750 °C without the AlPi. This paper first aims to describe the mechanism of action of an intumescent coating to protect a polymer, as it was never previously studied in the literature. It was evidenced, analyzing with 13C, 31P and 27Al solid state NMR spectra of the materials at different combustion times that during burning one part of the virgin polymer begins to degrade and is mixed with the semi-viscous charring intumescent layer. In some way, due to this mixture of both phases, it is as if the polymer was fire retarded in bulk during burning. The second objective was to investigate the potential synergy between the gas phase fire-retardant mechanism of AlPi and the condensed phase fire protective mechanism of the intumescent coating to explain the enhanced fire-retardant properties. Similarly, using NMR technique, the interest to combine the bulk treatment in low amount and the intumescent coating was evidenced: the AlPi cannot completely sublimate because of the protective coating, and is probably condensed inside the intumescent structure pores. As it is trapped in the condensed phase, it then degrades into aluminophosphates, increasing the heat barrier efficiency of the expanded char layer.

Zinc compounds as flame retardants and smoke suppressants for rigid PVC

The effect of the concentration of zinc hydroxy-stannate and zinc borate on the fire performance of rigid PVC formulations has been investigated. Fire testing was carried out using cone calorimetry as well as the limiting oxygen index (LOI) test. In addition, further testing was done to check that incorporation of the fire retardant additives did not have any detrimental effects on other properties of the formulated PVC, such as heat stability, colour or impact strength. The results demonstrated that zinc hydroxy-stannate is an excellent fire retardant and smoke suppressant at additions levels of 3 parts per hundred parts of PVC. Zinc borate did not have the excellent fire retardant properties of zinc hydroxy-stannate, but was found to be an efficient and cost-effective smoke suppressant, although the presence of free zinc oxide in the sample affected the thermal stability of the formulation.