New intumescent flame‐retardant agent: Application to polyurethane coatings

The first part of this investigation focused on the synthesis and characterization of a new type of intumescent flame‐retardant (IFR) agent. Four steps were used in the synthesis process. The structure was characterized by FTIR, magic‐angle spinning nuclear magnetic resonance (MAS‐NMR) ¹³C spectroscopy, and elemental analysis. The addition of an IFR agent into polyurethane (PU) varnish led to an improvement in its carbonization and flame‐retardant (FR) properties. The second part focused on the evaluation of such characteristics as FR property, thermal stability of IFR/PU‐based coatings, rheology of IFR/PU‐based coating solutions, and mechanical properties such as hardness, adhesion, and flexibility of IFR/PU‐based dry coating films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1193–1206, 2004     

Effect of expandable graphite on the properties of intumescent flame‐retardant polyurethane foam

Water‐blown rigid polyurethane foam (PUF) with two different particle sizes (180 and 300 μm) of expandable graphite (EG) as a flame‐retardant additive were prepared, and the effects on the mechanical, morphological, water absorption, thermal conductivity, thermal, and flame‐retardant properties were studied. In this investigation, EG content was varied from 5 to 50 php by weight. The mechanical properties of PUF decreased with increasing EG loading in both cases. The water absorption of the PUF increased with an increase in the EG loading mainly because of the collapse of foam cells, as evidenced from the scanning electron microscopy pictures. The thermal conductivity of the EG‐filled PUF showed that the insulation properties decreased with EG loading. The flame‐retardant properties (limiting oxygen index and char yield measurement) of the PUF improved with increasing EG loading. PUF filled with the higher particle size EG showed better mechanical properties and fire‐retardant properties than the PUF filled with the lower particle size EG. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Smoke suppression properties of epoxy crosslinked structure and intumescent fire retardant in epoxy‐based intumescent fire‐retardant coating

In this article, the smoke production behaviors of crosslinked epoxy/polyamide resin (EP/PA) and intumescent fire retardant (IFR) in epoxy‐based intumescent fire‐retardant coating (IFR‐EP) have been investigated using cone calorimeter, smoke density instrument, and thermogravimetric analysis and Fourier transform infrared spectroscopic measurement. The static and dynamic smoke production behaviors of EP/PA and IFR‐EP indicate that the IFR has an excellent smoke suppression effect on EP/PA by forming protective char layer in the late combustion stage, while the epoxy crosslinked structure in IFR‐EP can enhance the thermal stability and reduce smoke production in the early combustion stage. In addition, according to the discussion of pyrolysis gas products, the IFR can effectively suppress the production of toxic and inflammable gases during the combustion process. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43912.     

Effect of boric acid and melamine on the intumescent fire‐retardant coating composition for the fire protection of structural steel substrates

Intumescent coating is an insulating material designed to decrease heat transfer to a substrate structure. The coating presented in this research article was based on expandable graphite, ammonium polyphosphate, melamine, and boric acid. Bisphenol A epoxy resin BE‐188 was used as a binder with ACR hardener H‐2310 polyamide amine. Different formulations were developed to study the effect of expansion and heat shielding after fire testing. The coating was tested at 950°C for 1 h. The results show that the coating was stable and well bonded with the substrate. The coating was characterized with thermogravimetric analysis (TGA, Parkin Elmer, Norwalk, CT, 06859, USA), Fourier transform infrared (FTIR, Nicolet 400 D Shimadzu spectrometer) spectroscopy, X‐ray diffraction (XRD, Bruker D8 advance Diffracto meter, Bruker Germany), and scanning electron microscopy (SEM, Carl Zeiss Leo 1430VP, UK). The morphology of char was studied by SEM on the coating after fire testing. XRD and FTIR spectroscopy showed the presence of graphite, boron phosphate, boron oxide, and sassolite in the residual char. TGA (Pyris 1, manufactured by Parkin Elmer, Norwalk, CT, 06859, USA) and differential thermal gravimetric analysis (DTGA) showed that boric acid enhanced the residual weight of the intumescent fire‐retardant coating. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Intumescent foams—A novel flame retardant system for flexible polyurethane foams

A combination of intumescent components was evaluated as a novel flame retardant system in a flexible polyurethane foam, and the incorporation of these components gave rise to a significant enhancement of the flame retardant properties of the foam. The heat release rate was lowered at an early stage as well as throughout the fire, the total heat production was decreased and the time to ignition was prolonged. Mechanical measurements of the foam revealed enhanced properties in terms of stiffness accompanied by a large decrease in elongation at break as compared with a reference foam. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation of fire behavior of rigid polyurethane foams containing fly ash and intumescent flame retardant by using a cone calorimeter

Cone calorimeter is one of the most useful bench‐scale equipment which can simulate real‐world fire conditions. Therefore, cone calorimeter tests have been the most important and widely used tests for research and development of fire behavior of polymeric materials. In this study, fire behavior of rigid polyurethane foams containing fly ash (up to 5 wt %) and intumescent flame retardant (up to 5 wt %) composed of ammonium polyphosphate/pentaerythritol was investigated by using a cone calorimeter. In addition, thermogravimetric analysis of the additives and the foams were also carried out to explain the effects of fly ash and intumescent flame retardant on fire behavior of the foams. Experimental results indicated that rigid polyurethane foam containing fly ash and the intumescent flame retardant in comparison with pure rigid polyurethane foam shows significantly enhanced fire resistance and thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Evaluation and characterization of ammoniumpolyphosphate–pentaerythritol‐based systems for intumescent coatings

Intumescent coatings are increasingly used as a method of passive fire protection on steel constructions. By forming a carbon network and releasing a blowing agent, the thin intumescent film swells 100‐fold at elevated temperatures. The highly insulating foam effectively prevents the load bearing steel from reaching its critical temperature at which it looses its mechanical properties and collapses. The role of the carbon donor in intumescent coatings has been studied. Comparison in temperature development, foaming ratios, and rheological behavior has been performed between formulations containing pentaerythritol (penta), di–penta, and tri–penta. A simulated fire test, in which the temperature development during intumescence was studied, showed that the formulations containing penta were considerably more efficient in keeping a low temperature throughout the process. A more rapid temperature development was displayed when using di–penta and tri–penta as the carbon donor. Rheometer tests indicate that penta formulations enter the intumescent process at a lower temperature and stays in it for a longer time than di–penta and tri–penta formulations. Furthermore, the crossover temperature and maximum phase angle are shifted towards higher temperatures by replacing penta with di–penta and with tri–penta in the formulations, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 748–753, 2007     

DOPO‐VTS‐based coatings in the realm of fire retardants for cotton textile

The work elucidates the feasibility of incorporation of phosphorus‐silicon containing fire retardant (10‐(2‐trimethoxysilyl‐ethyl)‐9‐hydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide [DOPO‐VTS]) into nanosol coating solutions by cohydrolysis cocondensation reaction of DOPO‐VTS with tetraethoxysilane precursor (TEOS). Impregnation of cotton with the organophosphorus silane in a form of nanosol dispersion afforded better fire retardancy of such samples compared to pure DOPO or TEOS‐treated cotton indicating synergism between phosphorus and silicon containing species in a condensed phase. The detailed analysis by TGA‐MS and SEM pointed to the fact that DOPO‐VTS acts as a promoter of cotton degradation which, in turn, results in acceleration of the charring process and formation of compact char in contrast to TEOS‐treated samples. Further analysis of the char by XPS confirmed high content of carbonaceous residue in the case of DOPO‐VTS‐treated samples while mainly siliceous component was left in the char in case of cotton treated with TEOS. Standard flammability test (EN ISO 15025:2008) additionally confirmed the absence of smoldering and better overall fire performance of the DOPO‐VTS samples in contrast to TEOS‐treated samples. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41955.     

Synergistic effect of metal oxides on the flame retardancy and thermal degradation of novel intumescent flame‐retardant thermoplastic polyurethanes

The synergistic effects of some metal oxides on novel intumescent flame retardant (IFR)–thermoplastic polyurethane (TPU) composites were evaluated by limiting oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), cone calorimetry, and scanning electron microscopy. The experimental data indicated that the metal oxides enhanced the LOI value and restricted the dropping of the composites. The IFR–TPU composites passed the UL‐94 V‐0 rating test (1.6 mm) in the presence of magnesium oxide (MgO) and ferric oxide (Fe₂O₃) at 35 wt % IFR loading, whereas only the MgO‐containing IFR–TPU composite reached a UL‐94 V‐0 rating at 30 wt % IFR loading. The TGA results show that the metal oxides had different effects on the process of thermal degradation of the IFR–TPU compositions. MgO easily reacted with polyphosphoric acid generated by the decomposition of ammonium polyphosphate (APP) to produce magnesium phosphate. MgO and Fe₂O₃ showed low flammability and smoke emission due to peak heat release rate, peak smoke production rate, total heat release, and total smoke production (TSP). However, zinc oxide brought an increase in the smoke production rate and TSP values. Among the metal oxides, MgO provided an impressive promotion on the LOI value. The alkaline metal oxide MgO more easily reacted with APP in IFRs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A formaldehyde‐free flame retardant wood particleboard system based on two‐component polyurethane adhesive

To address the problem of formaldehyde‐free flame retardation of wood particleboard, a novel phosphorus‐containing compound, di(2,2‐dimethyl‐1,3‐propanediol phosphate) urea (DDPPU) was synthesized. DDPPU was used as flame retardant for wood particleboard. The flammability of treated wood particleboard systems consisted of wood particles, polyurethane (PU) adhesive, and different flame retardant formulations were investigated by limiting oxygen index (LOI). The results of LOI indicate that DDPPU could improve the flame retardancy of wood particleboard. However, when H₃BO₃ was used as the second flame retardant component and combined with DDPPU, the flame retardant wood particleboard could obtain the highest LOI value (46.0) in these experiments. Thermogravimetric analysis shows that treated wood particleboard can decrease the initial decomposition temperature, and that at higher temperatures the degradation rate are lower than the untreated wood particleboard. Furthermore, wood particleboard treated with DDPPU/H₃BO₃ has a higher yield of residue char at 600°C than that treated with other flame retardant systems. The ability of char formation of these samples agrees with the order of LOI values. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Aging of the flame‐retardant properties of polycarbonate and polypropylene protected by an intumescent coating

Flame retardancy (FR) in polycarbonate (PC) and polypropylene (PP) was obtained through the application of an intumescent coating on the polymeric substrate. A better performance was obtained with PC, a char former and highly viscous polymer, compared to with PP. Indeed, whereas 61 μm was required to obtain good FR (by the UL94 V0 rating, in particular) in the case of PC, at least 158 μm needed to be used to give FR to PP. The aging of the coated materials induced by UV‐filtered light radiation was then studied. This exposure led to a decrease in the FR. This effect was more pronounced in the case of PP compared to that of PC. The decrease in the FR was attributed to a decrease in the adhesion of the coating on the polymeric substrate because of its suspected physical aging. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39566.     

Flame retardancy and crack resistance of transparent intumescent fire‐resistive coatings

In this article, dihydroxy polydimethylsiloxane (n = 5–10) was introduced into the structure of polyphosphate (PPE) to get siloxane‐modified polyphosphate (SiPPE). Five kinds of SiPPEs with different Si contents were obtained. FTIR (Fourier Transform Infrared spectroscopy) ICP (Inductively Coupled Plasma Emission Spectroscopy), ³¹P NMR (Nuclear Magnetic Resonance Spectroscopy) and TGA (Thermogravimetric Analysis) were used to characterize the composition and structure of PPE and SiPPEs. Six kinds of transparent fire‐resistive coatings were prepared by the mixing of amino resin with PPE and five kinds of SiPPEs. The results of the fire protection test showed that both the fire‐resistive time of coatings and intumescent factor of char layers increased with the increase in content of Si. The results of TGA demonstrated that the carbonaceous residue of coating also increased regularly. The hardness, flexibility, digital photos, SEM (Scanning Electronic Microscopy) and other testing results showed that the introduction of silicon oxygen segment can effectively improve the crack resistance. The charcoal layer structure was more solid than before and collapse was not obvious after long time flame shock. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42423.     

A facile one‐step synthesis of flame‐retardant coatings on cotton fabric via ultrasound irradiation

This article reports a facile one‐step methodology to increase fire resistance properties of cotton fabric. The flame‐retardant coating for cotton fabric was synthesized with methyltriethoxysilane and organophosphates (M102B) through an ultrasound irradiation process. The coating structure and surface morphology of uncoated and coated fabrics were investigated by Fourier transform infrared spectroscopy and scanning electron microscope, respectively. The flame‐retardant properties, bending modulus, air permeability and thermal stability were studied by vertical burning test, cantilever method, air permeability test and thermogravimetric analysis (TGA). As a result, the cotton fabric coated with 29.2% (mass increased) of flame‐retardant coating was able to balance the flame retardant property and wearing comfort of the fabrics. The TGA results showed that the residue char of cotton was greatly enhanced after treatment with the coating, which has a high char forming effect on cellulose during testing. Furthermore, flame‐retardant property of coated fabrics did not change significantly after 10 washing cycles. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45114.     

Bamboo tar‐based polyurethane wood coatings

Bamboo tar is a natural resource of aromatic polyol obtained from a residue of by setting or distilling crude bamboo vinegar. In this study, the two‐packed polyurethane (PU) coatings were prepared by blending bamboo tar and castor oil varying with different weight ratios and polymeric toluene diisocyanate (PTDI) was used as a hardener at the NCO/OH molar ratio of 1.0. Six kinds of PU coatings were formulated and the viscosity, pot‐life, drying time, mechanical properties (hardness, tensile strength, impact resistance, adhesion, and abrasion resistance), gel content, durability, lightfastness, FTIR, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) were characterized. The results indicated that the bamboo tar containing PU film appearance is semitransparent yellow‐brown color and the wood texture could be kept after finishing. All PU films possessed excellent adhesion as well as durability. The increase in bamboo tar content led to shorten drying time of coatings and to increase in hardness, tensile strength, lightfastness, and thermal stability of films. From these results and due to a light smell flavor, it is suggested that the bamboo tar‐based PU coatings is suitable to be used as an exterior wood coatings. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A commercial phosphorous–nitrogen containing intumescent flame retardant for thermoplastic polyurethane

The aim of this work is to develop a halogen‐free thermoplastic polyurethane (TPU) composite with significantly improved fire performance by using a highly commercial phosphorous–nitrogen containing intumescent flame retardant (P–N IFR). Based on the characterizations of thermogravimetric analysis and in situ Fourier transform infrared spectra, P–N IFR powder was proved a desired flame retardant for TPU in theory and the thermal degradation property of PU/PNIFR composites at elevated temperatures was investigated as well. Fire performance was evaluated by limiting oxygen index, underwriters laboratories 94 testing and char residue morphologies. Results showed that the addition of P–N IFR promotes the formation of char residues which were covered on the surface of polymer composites resulting in the improvement of thermal stability and flame retardancy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39772.     

茶皂素基膨胀型阻燃剂的制备及其在涂料中的应用

采用多羟基、多羧基的活性天然产物茶皂素为原料,与聚磷酸铵和季戊四醇在一定条件下反应,制备一种聚磷酸酯类茶皂素基三位一体新型环保膨胀型阻燃剂。采用傅里叶红外分析技术对阻燃剂进行了结构表征,采用综合热分析仪对阻燃剂的热降解性能进行了研究。结果表明,茶皂素与聚磷酸铵、季戊四醇发生反应,生成聚磷酸酯类茶皂素基膨胀型阻燃剂,且该阻燃剂具有良好的热稳定性,降解热释放较小,高温残留率高,最终的质量残留率高达30.77%。将制备阻燃剂用于阻燃涂料中,并采用氧指数测试仪和锥形量热仪研究了阻燃涂料的阻燃性能和热解性能。研究表明,茶皂素基三位一体膨胀型阻燃剂能显著提高涂料的阻燃性能,阻燃涂料的氧指数值高达34.2%,耐火时间为11.1 min,且锥形量热实验中,该阻燃涂料试样的平均热释放速率（m-HRR）为36.18 kW/m2,总热释放量（THR）为5.25 kJ/m2,平均有效燃烧热（m-EHC）为5.11 kJ/kg,与含复合型阻燃剂的阻燃涂料试样相比,阻燃性能得到极大提高。该制备阻燃剂不含卤素,集三源一体,具有阻燃性能优越,相容性能良好,高效环保等优点。     

Preparation and application of phosphorous‐containing bio‐polyols in polyurethane foams

A bio‐polyol phosphonate acting as the polyol component in the preparation of polyurethane foam was synthesized from the liquefaction product of bagasse by the halogenation of the liquefaction product followed by the Michaelis–Arbuzov rearrangement. The FT‐IR spectra showed that phosphorus‐containing groups were introduced into the polyol chain. The data of the viscosity and the hydroxyl number suggested that the bio‐polyol phosphonate would be a good polyol component in the preparation of polyurethane foam. The limiting oxygen index of polyurethane foam containing bio‐polyol phosphonate varied in the range of 24–28, while that of polyurethane foam without bio‐polyol phosphonate was 23, demonstrating that the introduction of the phosphorus‐containing group into the polymer helped to improve the flame retardancy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40422.     

Effect of clay dispersion on the synergism between clay and intumescent flame retardants in polystyrene

Different formulations were designed to evaluate the effect of organically modified clay (DK4) on the combustion behavior of polystyrene (PS) containing an intumescent flame retardant, poly(4,4‐diaminodiphenyl methane spirocyclic pentaerythritol bisphosphonate) (PDSPB). The results of transmission electron microscopy reveal that DK4 selectively dispersed in the PDSPB phase. An investigation of thermogravimetric analysis revealed that the thermal stability of PS resin showed no obvious change with the addition of PDSPB and DK4, but the residue increased. From the results of cone calorimetry, we observed that there were two steps during combustion. The dispersion of DK4 played an important role in improving the thermal stability and the flammability of the PS/PDSPB/DK4 nanocomposites. In the first step, DK4 was restricted in the PDSPB phase; there was no synergistic effect. A synergistic effect occurred in the second step when clay had a homogeneous distribution, in which the peak heat release rates were reduced by about 40 and 61% compared to the pure PS. A model of combustion behavior was developed according to these results. The synergistic mechanism was caused by the formation of the silicoaluminophosphate (SAPO) structure formed by reactions between PDSPB and DK4. Field emission scanning electron microscopy characterization showed that such an SAPO structure led to a ceramic‐like residue after burning. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A facile strategy to fabricate microencapsulated expandable graphite as a flame‐retardant for rigid polyurethane foams

A facile strategy is reported for one‐step preparation of reactive microencapsulated expandable graphite (EG) for flame‐retardant rigid polyurethane foams (RPUF), which is based on in situ emulsion polymerization and the use of poly(glycidyl methacrylate) (PGMA) as reactive polymer shell. FTIR and SEM observations well demonstrate the formation of PGMA microencapsulated EG (EG@PGMA) particles. The encapsulation of PGMA shell significantly improves the expandability of EG particles from 42 to 70 mL g^?1. RPUF/EG@PGMA composite with only 10 wt % EG@PGMA loading reaches the UL‐94 V‐0 rating. The limiting oxygen indexes increase remarkably from 21.0 to 27.5 vol %. Additionally, the improved chemical and physical interaction enhance the interfacial bonding between EG and matrix, thus resulting in improved mechanical properties of RPUF/EG@PGMA. These attractive features suggest that the strategy proposed here can serve as a promising means to prepare highly efficient, reactive microencapsulated EG and corresponding good flame‐retarding RPUF with high mechanical properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42364.     

Effect of nitrocellulose on the properties of PU–NC semi‐IPN wood coatings

Wood coatings of PU–NC semi‐interpenetrating polymer networks (semi‐IPNs), made from blown castor oil (BCO), aromatic polyisocyanate (PTDI), and nitrocellulose (NC), were prepared by sequential polymerization method. To investigate the effects of NC on the properties of PU–NC semi‐IPNs wood coatings, three different viscosities of NC (½‐sec, ¼‐sec, and ${1\over 16}$ ‐sec), and a PU catalyst [dibutyltin dilaurate (DBTDL)] were synthesized in this study. The results revealed that the PU–NC semi‐IPNs with ½‐sec NC‐containing coating had the shortest drying time, and their films had the best tensile strength, elongation at break, lightfastness, and solvent resistance. Dynamic mechanical analysis showed that PU–NC semi‐IPNs with ½‐sec NC or ${1\over 16}$ ‐sec NC had good interpenetration between PU and NC, whereas PU–NC semi‐IPNs with ¼‐sec NC had a slight separation phase between PU and NC. In both PU–NC semi‐IPNs with ¼‐sec NC and those with ${1\over 16}$ ‐sec NC, the addition of 0.2% DBTDL could effectively reduce the drying time of the coating and improve the film properties, including tensile strength, elongation at break, and lightfastness. In addition, the miscibility of PU and NC was examined in PU–NC semi‐IPNs with ¼‐sec NC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2157–2162, 2003