Improvement of Flame Retardancy of Polyurethane Foam Using DOPO-Immobilized Silica Aerogel

In this work, silica aerogel was modified by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-1-oxide (DOPO). Then DOPO-immobilized silica aerogel nanoparticles were used as a flame retardant to prepare flame-retardant polyurethane foams. Microscale combustion calorimeter and cone calorimeter tests were employed to evaluate the flame retardancy of polyurethane foams. It was found that both the heat release rate and the total heat release of the composites were reduced with the incorporation of DOPO immobilized silica aerogel. It is speculated that the DOPO-immobilized silica aerogel nanoparticles can inhibit the degradation of polyurethane and catalyze the formation of carbonaceous carbon on the surface.

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Effects of an Organic-Inorganic Hybrid Containing Allyl Benzoxazine and POSS on Thermal Properties and Flame Retardancy of Epoxy Resin

Polymers ◽

10.3390/polym11050770 ◽

2019 ◽

Vol 11 (5) ◽

pp. 770 ◽

Cited By ~ 4

Author(s):

Benben Liu ◽

Huiling Wang ◽

Xiaoyan Guo ◽

Rongjie Yang ◽

Xiangmei Li

Keyword(s):

Thermal Properties ◽

Heat Release ◽

Flame Retardant ◽

Epoxy Resin ◽

Heat Release Rate ◽

Flame Retardancy ◽

Release Rate ◽

Cone Calorimeter ◽

Inorganic Hybrid ◽

X Ray

A novel organic-inorganic hybrid containing allyl benzoxazine and polyhedral oligomeric silsesquioxane (POSS) was synthesized by the thiol-ene (click) reaction. The benzoxazine (BOZ)-containing POSS (SPOSS-BOZ) copolymerized with benzoxazine/epoxy resin was used to prepare composites of SPOSS-PBZ-E nanocomposites(NPs). The polymerization behavior was monitored by FTIR and non-isothermal differential scanning calorimetry (DSC), which showed that the composites had completely cured with multiple polymerization mechanisms according to the oxazine ring-opening and epoxy resin (EP) polymerization. The thermal properties of the organic–inorganic polybenzoxazine (PBZ) nanocomposites were analyzed by DSC and thermogravimetric analysis (TGA). Furthermore, the X-ray diffraction analysis and the scanning electron microscopy (SEM) micrographs of the SPOSS-PBZ-E nanocomposites indicated that SPOSS was chemically incorporated into the hybrid nanocomposites in the size range of 80–200 nm. The flame retardancy of the benzoxazine epoxy resin composites was investigated by limiting oxygen index (LOI), UL 94 vertical burn test, and cone calorimeter tests. When the amount of SPOSS reached 10% or more, the vertical burning rating of the curing system arrived at V-1, and when the SPOSS-BOZ content reached 20 wt %, the thermal stability and flame retardancy of the material were both improved. Moreover, in the cone calorimeter testing, the addition of SPOSS-BOZ hindered the decomposition of the composites and led to a reduction in the peak heat release rate (pHRR), the average heat release rate (aHRR), and the total heat release (THR) values by about 20%, 25%, and 25%, respectively. The morphologies of the chars were also studied by SEM and energy dispersive X-ray spectroscopy (EDX), and the flame-retardant mechanism of POSS was mainly a condensed-phase flame retardant. The ceramic layer was formed by the enrichment of silicon on the char surface. When there are enough POSS nanoparticles, it can effectively protect the combustion of internal polymers.

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Synthesis and characterization of flame-retardant-wrapped carbon nanotubes and its flame retardancy in epoxy nanocomposites

Polymers and Polymer Composites ◽

10.1177/09673911211024582 ◽

2021 ◽

pp. 096739112110245

Author(s):

Jiangbo Wang

Keyword(s):

Carbon Nanotubes ◽

Heat Release ◽

Flame Retardant ◽

Flame Retardancy ◽

Total Heat Release ◽

Pristine Cnts ◽

Peak Heat Release Rate ◽

Ep Matrix ◽

Better Than

A novel phosphorus-silicon containing flame-retardant DOPO-V-PA was used to wrap carbon nanotubes (CNTs). The results of FTIR, XPS, TEM and TGA measurements exhibited that DOPO-V-PA has been successfully grafted onto the surfaces of CNTs, and the CNTs-DOPO-V-PA was obtained. The CNTs-DOPO-V-PA was subsequently incorporated into epoxy resin (EP) for improving the flame retardancy and dispersion. Compared with pure EP, the addition of 2 wt% CNTs-DOPO-V-PA into the EP matrix could achieve better flame retardancy of EP nanocomposites, such as a 30.5% reduction in peak heat release rate (PHRR) and 8.1% reduction in total heat release (THR). Furthermore, DMTA results clearly indicated that the dispersion for CNTs-DOPO-V-PA in EP matrix was better than pristine CNTs.

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Synthesis of a phosphorus–nitrogen-containing flame retardant and its application in epoxy resin

High Performance Polymers ◽

10.1177/0954008318756496 ◽

2018 ◽

Vol 31 (2) ◽

pp. 186-196 ◽

Cited By ~ 12

Author(s):

Shuang Yang ◽

Yefa Hu ◽

Qiaoxin Zhang

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Epoxy Resin ◽

Heat Release Rate ◽

Flame Retardancy ◽

Release Rate ◽

Epoxy Resins ◽

Proton Nuclear Magnetic Resonance ◽

Scanning Calorimetry ◽

Cone Calorimeter Test

In this article, a phosphorus–nitrogen-containing flame retardant (DOPO-T) was successfully synthesized by nucleophilic substitution reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and cyanuric chloride. The chemical structure of DOPO-T was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) and phosphorous-31 NMR, and elemental analysis. DOPO-T was then blended with diglycidyl ether of bisphenol-A to prepare flame-retardant epoxy resins. Thermal properties, flame retardancy, and combustion behavior of the cured epoxy resins were evaluated by differential scanning calorimetry, thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the glass transition temperature ( Tg) and temperature at 5% weight loss of epoxy resin (EP)/DOPO-T thermosets were gradually decreased with the increasing content of DOPO-T. DOPO-T catalyzed the decomposition of EP matrix in advance. The flame-retardant performance of EP thermosets was significantly enhanced with the addition of DOPO-T. EP/DOPO-T-0.9 sample had an LOI value of 36.2% and achieved UL94 V-1 rating. In addition, the average of heat release rate, peak of heat release rate, average of effective heat of combustion, and total heat release (THR) of EP/DOPO-T-0.9 sample were decreased by 32%, 48%, 23%, and 31%, respectively, compared with the neat EP sample. Impressively, EP/DOPO-T thermosets acquired excellent flame retardancy under low loading of flame retardant.

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Some Key Factors Influencing the Flame Retardancy of EDA-DOPO Containing Flexible Polyurethane Foams

Polymers ◽

10.3390/polym10101115 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1115 ◽

Cited By ~ 4

Author(s):

Agnieszka Przystas ◽

Milijana Jovic ◽

Khalifah Salmeia ◽

Daniel Rentsch ◽

Laurent Ferry ◽

...

Keyword(s):

Flame Retardancy ◽

High Speed ◽

Combustion Efficiency ◽

Polyurethane Foams ◽

Key Factors ◽

Ul 94 ◽

Microscale Combustion Calorimeter ◽

Flexible Polyurethane ◽

Combustion Calorimeter ◽

Pu Foams

The role of various additives (emulsifier, anti-dripping agent) and formulation procedures (pre-dispersion of solid additives in polyol via milling) which influence the flame retardancy of 6,6′-[ethan-1,2-diylbis(azandiyl)]bis(6H-dibenzo[c,e][1,2]oxaphosphin-6-oxid) (EDA-DOPO) containing flexible polyurethane foams has been investigated in this work. For comparison, the flame retardancy of two additional structurally-analogous bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based compounds, i.e., ethanolamine-DOPO (ETA-DOPO) and ethylene glycol-DOPO (EG-DOPO) were also evaluated together with EDA-DOPO in flexible PU foams of various formulations. The flame retardancy of these three bridged-DOPO compounds depends on the type of PU formulation. For certain PU formulations containing EDA-DOPO, lower fire performance was observed. Addition of emulsifier and polytetrafluoroethylene (PTFE) to these PU formulations influenced positively the flame retardancy of EDA-DOPO/PU foams. In addition, dispersion of EDA-DOPO and PTFE via milling in polyol improved the flame retardancy of the PU foams. Mechanistic studies performed using a microscale combustion calorimeter (MCC) and its coupling to FTIR showed no difference in the combustion efficiency of the bridged-DOPO compounds in PU foams. From MCC experiments it can be concluded that these bridged-DOPO compounds and their decomposition products may work primarily in the gas phase as flame inhibitors. The physiochemical behavior of additives in PU formulation responsible for the improvement in the flame retardancy of PU foams was further investigated by studying the dripping behavior of the PU foams in the UL 94 HB test. A high-speed camera was used to study the dripping behavior in the UL 94 HB test and results indicate a considerable reduction of the total number of melt drips and flaming drips for the flame retardant formulations. This reduction in melt drips and flaming drips during the UL 94 HB tests help PU foams achieve higher fire classification.

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Investigation of Flammable Behavior of Nylon 6 Fabrics with and without Spandex Using Cone Calorimeter Test and Vertical Burning Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.852.644 ◽

2014 ◽

Vol 852 ◽

pp. 644-647

Author(s):

Sheng Li Luo ◽

Hai Liang Zhang ◽

Zhi Cheng Zhan ◽

Bing He Mao ◽

Zhi Jie Jiang ◽

...

Keyword(s):

Heat Release ◽

Release Rate ◽

Cone Calorimeter ◽

Nylon 6 ◽

Test Results ◽

Total Heat Release ◽

Combustion Behavior ◽

Textile Fabrics ◽

Cone Calorimeter Test ◽

Nylon Fiber

To study the influence of spandex on combustion behavior of textile fabrics, two kinds of nylon 6 fabrics were tested using cone calorimeter test and vertical burning test. Some key combustion parameters such as heat release rate (HRR), total heat release (THR) and rate of smoke release (RSR) were obtained from cone calorimeter test and afterflame time and damaged length from vertical burning test. Results indicated that the nylon 6 fabric containing spandex showed 21% higher HRR value. But THRs of the nylon 6 fabric containing spandex and the pure nylon 6 fabric were close. RSR curves indicated that RSR value of the nylon 6 fabric containing spandex was 73% higher than that of the pure nylon 6 fabric. The afterflame time and damaged length of the nylon 6 fabric containing spandex were much longer than that of the pure nylon 6 fabric. Spandex does accelerate the combustion behavior on Nylon fiber.

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Flame Retardancy and Mechanical Property of Bi-Layer Polypropylene Sheets with Flame Retardant Selective Distribution

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.396-398.2145 ◽

2011 ◽

Vol 396-398 ◽

pp. 2145-2148

Author(s):

Yuan Yuan Xu ◽

Zheng Hong Guo ◽

Zheng Ping Fang ◽

Yu Wu

Keyword(s):

Mechanical Property ◽

Tensile Strength ◽

Mass Loss ◽

Flame Retardant ◽

Flame Retardancy ◽

Release Rate ◽

Cone Calorimeter ◽

Fracture Strain ◽

Selective Distribution ◽

Char Layer

The flame performance and mechanical property of bi-layer polypropylene/intumescent flame retardant/clay (PP/IFR/clay) sheets with flame retardant selective distribution were studied. The cone calorimeter measurements demonstrated that the selective distributed IFR can further reduce the peak first heat release rate (PHRR1), especially for the reduction in normalized mass loss. The digital images for the char residues after cone tests suggested that the char layer formed by the IFR particles in the selective distribution PP samples was more rapid and effective. The presence of IFR particles decreased the tensile strength and fracture strain of PP/IFR composites. The IFR composite with IFR particles selective in one layer can improve the fracture strain.

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Enhanced Thermal Insulation and Flame-Retardant Properties of Polyvinyl Alcohol-Based Aerogels Composited with Ammonium Polyphosphate and Chitosan

International Journal of Polymer Science ◽

10.1155/2021/5555916 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

MinYi Luo ◽

Jiayou Xu ◽

Shu Lv ◽

XueFeng Yuan ◽

Xiaolan Liang

Keyword(s):

Polyvinyl Alcohol ◽

Heat Release ◽

Flame Retardant ◽

Thermal Insulation ◽

Heat Release Rate ◽

Flame Retardancy ◽

Release Rate ◽

Ammonium Polyphosphate ◽

Composite Aerogel ◽

Composite Aerogels

Polyvinyl alcohol- (PVA-) based aerogels have attracted widespread attention owing to their low cost, eco-friendliness, and low density. However, the applications of PVA-based aerogels are limited by their flammability. In this study, a flame retardant, ammonium polyphosphate (APP), and a biopolymer, chitosan (CS), were added to polyvinyl alcohol (PVA), and the polymer was further crosslinked using boric acid (H3BO3). In the PVA aerogels, the negatively charged APP and positively charged CS formed a polyelectrolyte complex (PEC) through ionic interaction. Cone calorimetry and vertical burning tests (UL-94) indicated that the PVA composite aerogels have excellent flame retardancy; they could decrease the heat release rate, total heat release rate, and carbon dioxide (CO2) generation. Both PVA/H3BO3 and APP-CS in the composite aerogel could be burned to carbon, and the foamed char layer could act together to impart the PVA composite aerogels with good flame retardancy. Further, the decrease in the temperature at the backside of the aerogels with increasing APP-CS content, as determined by the flame-spraying experiment, indicated that the PVA-based aerogels with APP-CS can also serve as thermal insulation materials. This work provides an effective and promising method for the preparation of PVA-based aerogels with good flame retardancy and thermal insulation property for construction materials.

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Environmentally Benign Phytic Acid-Based Nanocoating for Multifunctional Flame-Retardant/Antibacterial Cotton

Fibers ◽

10.3390/fib9110069 ◽

2021 ◽

Vol 9 (11) ◽

pp. 69

Author(s):

Eva Magovac ◽

Bojana Vončina ◽

Ana Budimir ◽

Igor Jordanov ◽

Jaime C. Grunlan ◽

...

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Phytic Acid ◽

Environmentally Benign ◽

Lower Amount ◽

Layer By Layer ◽

Limiting Oxygen Index ◽

Untreated Cotton ◽

Microscale Combustion Calorimeter ◽

Combustion Calorimeter

Environmentally benign layer-by-layer (LbL) deposition was used to obtain flame-retardant and antimicrobial cotton. Cotton was coated with 8, 10, and 12 phytic acid (PA) and chitosan (CH)-urea bilayers (BL) and then immersed into copper (II) sulfate (CuSO4) solution. Our findings were that 12 BL of PA/CH-urea + Cu2+ were able to stop flame on cotton during vertical flammability testing (VFT) with a limiting oxygen index (LOI) value of 26%. Microscale combustion calorimeter (MCC) data showed a reduction of peak heat release rates (pHRR) of more than 61%, while the reduction of total heat release (THR) was more than 54%, relative to untreated cotton. TG-IR analysis of 12 BL-treated cotton showed the release of water, methane, carbon dioxide, carbon monoxide, and aldehydes, while by adding Cu2+ ions, the treated cotton produces a lower amount of methane. Treated cotton also showed no levoglucosan. The intumescent behavior of the treatment was indicated by the bubbled structure of the post-burn char. Antibacterial testing showed a 100% reduction of Klebsiella pneumoniae and Staphylococcus aureus. In this study, cotton was successfully functionalized with a multifunctional ecologically benign flame-retardant and antibacterial nanocoating, by means of LbL deposition.

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The effects of N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol on the flame retardancy and physical–mechanical properties of rigid polyurethane foams

Journal of Fire Sciences ◽

10.1177/0734904118806648 ◽

2018 ◽

Vol 36 (6) ◽

pp. 535-545 ◽

Cited By ~ 4

Author(s):

Daikun Jia ◽

Yi Tong ◽

Jin Hu

Keyword(s):

Flame Retardant ◽

Polyurethane Foam ◽

Flame Retardancy ◽

Cone Calorimeter ◽

Oxygen Index ◽

Polyurethane Foams ◽

Initial Decomposition Temperature ◽

Limiting Oxygen Index ◽

Rigid Polyurethane Foams ◽

Upper Limit

Flame-retardant rigid polyurethane foams incorporating N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol have been prepared. After adding N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol, the density and compressive strength of the polyurethane foams were seen to decrease. The flame retardancy of the polyurethane foams has been characterized by limiting oxygen index, upper limit–94, and cone calorimeter tests. The polyurethane foam with 2.27 wt% N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol gave a highest limiting oxygen index of 33.4%, and the peak heat release rate of polyurethane foam reduced to 19.5 kW/m2 from 47.6 kW/m2 of PU-0 without N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol. Upper limit–94 revealed N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol did not change the burning rating, and all polyurethane foams had passed V-0 rating. The thermal stability of polyurethane foams has been investigated by thermogravimetric analyzer. N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly increased the initial decomposition temperature of polyurethane foams and their residues. In addition, the morphology of residual char from the flame-retarded polyurethane foams after cone calorimeter tests has also been characterized by digital photographs. The results indicated that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly enhanced the strength and compatibility of the char layer formed by the polyurethane foams. These results indicate that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol can improve both the quality and quantity of the char, which has a significant effect on the flame-retardant properties of the foam.

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Flame Retardation of Natural Bamboo Fiber/ Polypropylene Fiber Non-Woven Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.105-107.1723 ◽

2011 ◽

Vol 105-107 ◽

pp. 1723-1726

Author(s):

Wei Ma ◽

Wen Bin Yao

Keyword(s):

Heat Release ◽

Flame Retardant ◽

Heat Release Rate ◽

Release Rate ◽

Cone Calorimeter ◽

Polypropylene Fiber ◽

Bamboo Fiber ◽

Peak Heat Release Rate ◽

Natural Bamboo Fiber ◽

Flame Retardation

According to Natural Bamboo Fiber/ Polypropylene fiber(PP) non-woven materials encountered the problem that its flame retardation is insufficient, this paper tried to add flame retardant to improve its performance, then the cone calorimeter was used to evaluate its flammability. The results show that Peak-Heat Release Rate and Smoke Release Rate etc significantly improved. In accordance with the UL94 ,the flame retardation meet the level V-0 , consistent with the requirements of enterprise.

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