Heat release and classification of fire retardant wood products

A comparison is presented of cone calorimeter heat release data between fire retardant treated and untreated wood products. The test results show significant differences between these two groups. The parameters included in the comparison are time to ignition, rate of heat release (peak and average values) and total heat release. The wood-based products were also tested in different small-scale national standard fire tests and in the full-scale room fire test. Fire retardant wood products achieve an improved classification both in present national systems and in possible new systems based on the cone calorimeter and the room fire test.     

Compression mechanical properties of wood at temperatures simulating fire conditions

Compression mechanical properties of wood at temperatures simulating fire conditions have been obtained for use in structural response models to aid the design of light-timber framed walls as fire barriers in accordance with recent performance-based fire codes. The properties that have been measured are elastic modulus and strength. The properties were obtained from samples that had a number of similarities to studs in walls. The effects of knots, however, have been excluded from this study. The elastic modulus greatly reduces as temperatures approach the vaporization point of moisture. The properties were significantly lower compared with properties given in the literature. Input of the measured properties into a structural fire model for walls led to good comparisons with results of experiments on walls with low load ratios (that is, the ratio of the applied load to the collapse load capacity at ambient conditions). Such walls are typically used in building construction. However, the elastic moduli presented in this paper and in other literature do not lead to good model predictions for slender walls with high load ratios. Further research into creep is required. Copyright © 2001 John Wiley & Sons, Ltd.     

Improving fire retardancy of fast growing wood by coating with fire retardant and surface densification

Fire retardant fast-growing wood product was developed by coating with fire retardant and densifying the surface of wood. Trimethylol melamineformaldehyde resin mixed with phosphoric acid was coated on the wood surface, preheated and followed by hot pressing. Effects of the amount of coating, preheating temperature, and densifying ratio on the fire retardancy of sugi (Cryptomeria japonica D. Don) wood, and pressing temperature and pressing time on that of albizia (Paraserianthes falcataria Becker) wood were discussed. Bending strength, creep performance under fire and fire retardancy were evaluated. The results showed that the treatments improved the fire retardancy of woods without reduction in the bending strength. © 1998 John Wiley & Sons, Ltd.     

Effectiveness of impregnation of ammonium polyphosphate fire retardant in poplar wood using microwave heating

Poplar samples were impregnated with ammonium polyphosphate fire retardant at various pressures and durations after they were pretreated with microwave heating. The effects of the pressure and duration on the flame‐retardation and smoke‐suppression properties were investigated with cone calorimeter analysis. The peak heat release rate (pk‐HRR), total heat release (THR), and total smoke product (TSP) of treated woods were measured for samples of pretreated and untreated with microwave. After the impregnation, the poplar wood showed the significant improvement in its fire resistance. Compared with non‐impregnation wood, the pk‐HRR, THR, and TSP of wood impregnated with ammonium polyphosphate at pressure of 0.4 MPa and duration of 10 min were 48.29%, 35.58%, and 68.64% less, respectively. The pk‐HRR, THR, and TSP of microwave pretreated wood was 15.89%, 5.69%, and 13.59% less than those without microwave pretreated sample. The microwave pretreatment of wood can increase fire retardant effectiveness of ammonium polyphosphate‐impregnated wood. Copyright © 2015 John Wiley & Sons, Ltd.     

Fire performance of wood (Pinus radiata) treated with fire retardants and a wood preservative

In this work, we co‐formulated an oil‐borne copper naphthenate/permethrin wood preservative system with synthetic polymer‐based fire‐retardant additives prior to the impregnation of Pinus radiata sapwood. We evaluated what effect, if any, the preservative had upon the fire performance properties of the fire retardants and whether the fire retardants impacted on the fungicidal and termiticidal efficacy of the preservative. The fire retardants included halogenated and phosphorus‐based systems. A mass loss calorimeter, in conjunction with a thermopile, was used to measure the time to ignition and the peak heat release rate (PHRR) from which the fire performance index (FPI) was determined. The preservative properties were evaluated using termite and soil‐block decay bioassays. In summary, we found that the rate of fire growth was reduced when the fire retardants were used in combination with the wood preservative. We also found that the PHRR was a better determinant of fire performance than the FPI. The performance of the wood preservative was enhanced against fungal decay and termite attack when used in combination with the fire retardants. The fire retardants also demonstrated some wood preservative properties of their own. Copyright © 2008 John Wiley & Sons, Ltd.     

Thermal degradation and fire performance of wood treated with various inorganic salts

The effects of Na₂WO₄, Na₂SnO₃, and Na₂MoO₄ on the thermal decomposition and fire performance of wood were characterized by thermogravimetric analysis, differential thermogravimetry, differential thermal analysis, and thermogravimetry–mass spectrometry analysis. The kinetics of thermal degradation were analyzed using Doyle's equation and the limiting oxygen index was shown to be enhanced by the addition of Na₂WO₄, Na₂SnO₃, and Na₂MoO₄. The addition of these chemicals caused a decrease in the decomposition temperature, a reduction in weight, and an increase in the amount of char produced. The activation energies of the samples were also decreased after treatment by these flame retardants, during both the charring stage and the calcining stage. The flame retardants were shown to be able to catalyze the dehydration reaction, resulting in the formation of more H₂O, CO₂, and char molecules, but less levoglucosan and levoglucose. Copyright © 2010 John Wiley & Sons, Ltd.     

阻燃防火硅橡胶研究进展

总结了国内外当前阻燃防火硅橡胶的研究进展,并重点介绍了阻燃剂和防火填料对硅橡胶性能的影响.在阻燃剂方面,介绍了目前常用的阻燃剂及其阻燃机理;在防火填料方面,对应用比较广泛的防火填料进行了介绍,并对其成瓷机理进行了阐述;最后提出了未来阻燃防火硅橡胶的研究方向.     

Thermal degradation and fire performance of wood treated with PMUF resin and boron compounds

Plantation Chinese fir wood was modified by low molecular weight phenol melamine urea formaldehyde (PMUF) resin, boron compounds (BB), and the mixture of PMUF/BB (PMUF‐BB), followed by a curing step. The fire performance and thermal degradation of wood was measured by limiting oxygen index instrument, cone calorimeter, and simultaneous thermal analysis. The results showed that the limiting oxygen index increased to 50.7%, 43.5%, and 55.0% for BB, PMUF, and PMUF‐BB samples, respectively. The PMUF resin decreased the heat release rate of wood but increased the total heat release compared with the control samples. The thermal analysis results demonstrated that PMUF resin enhanced the thermal stability of wood, however, had little impact on the residual chars. Combinative treatment with boron compounds could substantially reduce the fire risk for PMUF‐modified wood, making them especially useful for application in public settings.     

A review of products evolved from heated coal,wood and PVC

A review is presented of the gaseous combustion and pyrolysis products evolved from coal, wood and PVC. Information has been collated on the range of products evolved, the temperatures of evolution and the effect of different ambient conditions (e.g. oxidizing of inert conditions). The data for coal have been subdivided into those from which rates of gas evolution have been or can be derived and those from which this is not possible. Probable decomposition routes for PVC and for wood are discussed. Although all three materials have been widely studied, the correlation between the work of different authors in not always good. The data obtained are dependent on the form of the experiment, and there are gaps in the information available, especially information on the rates of evolution of products of products as a function of temperature.     

Modelling film formation and degradation of semi-transparent exterior wood coatings

Deposition and aggregation of small solid particles are encountered in many natural and industrial environments. These processes are of substantial significance for the development of a coating film on a wooden substrate. Formulating new coatings with improved performance and lower cost for exterior wooden joinery, mainly a trial-and-error approach, has a large influence on the initial film forming stage in a coating's life. Therefore modelling can supply insight in the particle–particle–substrate interaction. Two approaches are proposed. The first one uses a random point process to position the cluster centres and particles in a dry film. The second strategy starts with a random scattering of the particles in a wet film followed by Monte Carlo sampling and subsequently minimization of the total energy of the particle system. Surface roughness and gloss are calculated from the simulated surface structure. Next to these simulations, surface reconstruction of coated wood with confocal scanning laser microscopy (CSLM) is used to obtain surface roughness values and deduction of gloss applying the bidirectional reflection distribution function (BRDF) theory. As semi-transparent systems are the subject of gloss calculation on surfaces measured by CSLM and computer simulation, refractive index is estimated using an analytical solution of the reflectance and transmittance problem. Withal, coating and subsequent degradation simulation can become a valuable tool for screening purposes.     

新型硅硼磷阻燃剂的合成以及在防火涂料中的应用

以9,10⁃二氢⁃9⁃氧杂⁃10⁃磷杂菲⁃10⁃氧化物（DOPO）、二甲氧基甲基乙烯基硅氧烷（DTTLL）和硼酸［B（OH）₃］合成了一种分子结构中含有硅硼磷的阻燃剂（SiBP）。分别用傅里叶变换红外光谱仪（FTIR）和氢核磁共振光谱仪（¹H⁃NMR）表征了SiBP 的化学结构。用热失重分析仪（TG）表征了SiBP的热稳定性,在氮气氛围下SiBP的起始分解温度为110 ℃,并且在氮气气氛下800 ℃的残炭率高达40 %。以硅丙乳液为基体,通过加入多聚磷酸铵（APP）为协效阻燃剂,SiBP为主阻燃剂,双季戊四醇（Di⁃PE）,三聚氰胺（MEL）,无机填料硅微粉进行复配制备一种防火涂料。利用极限氧指数测定仪（LOI）,UL 94垂直燃烧测试、TG、大木板燃烧实验对其防火性能进行详细的表征和分析,利用扫描电子显微镜观察炭层燃烧后的微观和宏观形貌。通过压缩性能测试仪、电子万能试验机对炭层强度和涂料剥离强度进行表征。结果表明,当APP为10份（质量份,下同）、SiBP为20份、Di⁃PE为4份、MEL为8份、硅微粉为25份时,极限氧指数提高到29.2 %,UL 94达到V⁃0级,残炭率为38.5 %,剥离强度提高到0.325 kN/m,炭层压缩强度增加到1.4 MP,亲水性增加。     

阻燃陶瓷化硅橡胶的制备与性能

以硅橡胶为基质,通过添加玻璃粉和阻燃剂制备了兼具阻燃和耐火性能的陶瓷化硅橡胶材料,研究了阻燃剂氢氧化镁、氢氧化铝和硼酸锌对硅橡胶瓷化性能的影响,并通过扫描电子显微镜观察了瓷化物的断面形貌。结果表明,纯硅橡胶以及只添加玻璃粉的硅橡胶不具备足够的阻燃性,需要用少量阻燃剂替代部分玻璃粉。3种阻燃剂中硼酸锌的添加使硅橡胶具备了最佳的阻燃性,试样的极限氧指数达到48,垂直燃烧等级达到FV-0;氢氧化镁的添加使硅橡胶的陶瓷化效果更加明显,瓷化物的密度、吸水率和弯曲强度可分别达到1.633 4 g/cm3、9.86%和6.43 MPa。     

Kinetics of thermal degradation and fire retardant efficiency of polyesters

Seven polyesters having different amounts of halogen were studied for kientics of degradation and fire retardant efficiency. Out of them, the polyesters number 1, 2, 3, and 4 had the molar ratios of chlorendic acid to isophthalic acid of 0.25, 0.67, 1.5, and 4.0 respectively. The polyesters number 5, 6, and 7 were based on dimethyl-di-(p-oxyacetoxymethylphenyl)-methane, dimethyl-di-(3,5-dichloro-4-oxyacetoxymethylphenyl) methane and dimethyl-di-(3,5-dibromo-4-oxyacetoxymethylphenyl)-methane respectively. These studies were done with the help of thermogravimetric analysis (TGA), differential thermal analysis (DTA), infra-red spectroscopy and glow rod apparatus. The thermal stability of these polyesters decreased in the following order: 5 > 6 > 7 > 1 > 2 > 3 > 4, taking the threshold temperature as a measure of the thermal stability. The 50% weight loss temperature determined from TGA curves supported this to some extent. These studies further revealed that these polyesters degrade in two stages. The first stage of degradation ranged from 250–450°C. The second stage of degradation is in the range of 450–600°C. In the first stage, the range of temperature for degradation is constricted by increasing the halogen content. Bromination is more effective than chlorination. The activation energy for degradation of these polyesters showed the same trend as the thermal stability. But the flame resistance is somewhat in the reverse order of thermal stability. These studies also confirm a cyclic mechanism for flame retardancy.     

磷酸盐阻燃液的制备及阻燃棉布的应用

室内常用装饰材料大多是由棉、木材等易燃物质制成,易引发火灾、造成人员伤亡和财产损失。因此,对室内常用装饰材料的燃烧性能进行研究是非常必要的。磷酸盐阻燃剂作为一种添加型阻燃剂,采用喷涂或浸渍等方式使棉布、木材等室内常用装饰材料获得较好的阻燃性能。本文采用磷酸氢二铵和磷酸二氢铵作为原料,分别按9:1、8:2、7:3、6:4、5:5、4:6、3:7、2:8、1:9共9种不同的质量比例混合配制磷酸盐阻燃液,并应用于棉布进行浸泡阻燃处理,然后对样品进行阻燃性能表征。实验结果表明,2:8比例的阻燃处理棉布点燃时间和达到峰值时间最长,阻燃效果最佳,目前的研究对于后续改进磷酸盐阻燃液的阻燃性能并分析影响其性能的因素具有重要意义。     

Reaction to fire and water vapour resistance performance of treated wood specimens containing TiO2 and clay nanoparticles

The effect of TiO₂ and/or clay nanoparticles on water vapour permeability and the reaction to fire performance of coated and impregnated spruce wood were studied. Water vapour permeability properties were used to assess the moisture transfer properties and durability of the specimens using the cup test. The reaction to the early stage fire development properties of the specimens was analysed using a small scale cone calorimeter test. Comparisons between the different treated and untreated specimens on the moisture and reaction to fire performances were performed. The results revealed poor reaction to fire and water vapour resistance of specimens treated with TiO₂ and/or clay nanoparticles containing treatments. Copyright © 2013 John Wiley & Sons, Ltd.     

Comparison of disodium octaborate tetrahydrate‐based and tannin‐boron‐based formulations as fire retardant for wood structures

Boron‐based formulations are used to improve the service life of timber. On the one hand, boron‐treated wood increases resistance to biological attacks (e.g. by fungi and insects), and on the other hand, it renders wood more resistant to burning. In the present study, we analyse the fire behaviour of some water‐borne formulations containing boron. A completely inorganic formulation (disodium octaborate tetrahydrate (DOT)) is compared with new‐generation tannin‐based wood preservatives in which the flavonoid network is used to fix the boron to wood. The study of the fire behaviour was carried out according to four specific fire tests: (i) dripping; (ii) short‐term exposure; (iii) long‐term exposure and (iv) the limiting oxygen index. The Scots pine (Pinus sylvestris L.) specimens treated with DOT have shown a complete efficacy against fire after all tests were completed. It should also be noted that very positive results have also been achieved by the tannin‐based solutions. DOT has to be preferred when high performance is required, but exclusively for interior applications. The use of tannin‐based formulations can be suitable for outdoor fire protection and also for indoor applications when specific aesthetic requirements should be fulfilled. Copyright © 2013 John Wiley & Sons, Ltd.     

Development of poly(vinyl chloride)/wood composites. A literature review

Poly(vinyl chloride)/wood fiber (flour) composites are currently experiencing a dramatic increase in use. Most of them are used to produce window/door profiles, decking, railing, and siding by using conical counterrotating intermeshing twin‐screw extruders. Heat stabilizers, processing aids, impact modifiers, lubricants, and pigments are still important for PVC/wood composite formulations. Poly[methylene(polyphenyl isocyanate)] (PMPPIC), γ‐aminopropyltriethoxysilane, maleated polypropylene (MAPP), and copper metallic complex have proved to be effective coupling agents for this composite system. Mechanical properties of PVC/wood composites can be enhanced by combining wood with mica or glass fibers to form hybrid reinforcements. Ultraviolet light resistance and weathering dimensional stabilities of PVC/wood composites are superior to those of natural wood. Density reduction can be achieved through the microcellular foaming technique by using chemical blowing agents, such as azodicarbonamide and sodium bicarbonate, or physical blowing agents, such as carbon dioxide. J. Vinyl Addit. Technol. 10:59–69, 2004. © 2004 Society of Plastics Engineers.     

Green fire retardant finishing and combined dyeing of proteinous wool fabric

Flame retardancy was imparted to a scoured and bleached, proteinous woollen textile by using banana pseudostem sap, an ecofriendly waste agricultural product, at different pH levels. The flame retardancy characteristics of both the control and the treated fabrics were analysed in terms of the limiting oxygen index and the vertical flammability measurement. Thermal degradation and fire retardancy mechanisms were studied using thermogravimetry, scanning electron microscopy, and energy dispersive X‐ray analysis. Moreover, the charring mechanism of both the control and the banana‐pseudostem‐sap‐treated fabrics with varying pH was analysed and reported in detail. The wool fabric was also dyed with CI Acid Blue 25 using banana pseudostem sap as well as water as the medium. The fabric dyed with the banana pseudostem sap medium at pH 5.5 showed more colour exhaustion, colour strength, and thermal stability compared with the control wool fabric. The mechanism by which superior fire retardancy and colour strength are imparted to the woollen textile by the application of banana pseudostem sap is proposed.     

Experimental and theoretical behavior of exterior wood coatings subjected to artificial weathering

Several solvent- and water-borne exterior wood coatings were artificially weathered to study their performance behavior. Penetration and layer thickness were measured on unweathered samples and compared to theoretical estimates by means of measured basic parameters of coating and substrate. Color, surface roughness, gloss, and adhesion were monitored during aging, and the latter two were also calculated and compared to their experimental values. Theoretical values of gloss, and especially those of adhesion, were less successful on an absolute scale, but were in accordance with practical values on a relative scale. The influence of solid content, drying speed, and viscosity on penetration depth manifested itself clearly both in theory and in practice. In general, solvent-borne coatings performed well, but some water-borne coatings also showed good performance. By measuring the characteristics of a coating as described in this article, it is possible to rank the coatings and follow their weatherability. Finally, calculation of theoretical values proved a promising method for initial screening purpose.