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.     

Thermal and thermooxidative degradation of engineering thermoplastics and life estimation

This investigation deals with the thermal or thermooxidative degradation behavior of three engineering polymers [e.g., poly(ethylene terephthalate) (PET), poly(ether sulfone) (PES), and poly(ether ether ketone) (PEEK)] by using thermogravimetry‐coupled mass spectrometry (TG‐MS) analysis. The experiments were conducted both in argon and in air separately to study the changes in the degradation pattern of the polymers under varied sample environments. The samples were subjected to a programmed heating rate of 10°C/min and a temperature range from ambient to 800°C. For all these polymers, the decomposition rate, percentage weight loss, and the nature of the evolved gases were found to vary while changing the environment from argon to air. Methods of nonisothermal kinetic analysis, proposed by Flynn and Wall, and the shelf life estimation, proposed by Toop, have been described. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1737–1748, 2004     

Thermal degradation and fire performance of plywood treated with expanded vermiculite

The new flame‐retardant plywood was manufactured by adding expanded vermiculite (EVMT) in the adhesive and by surface treatment as a flame‐retardant coating. The study discussed the effect of EVMT to the limited oxygen index values of samples. The thermal degradation process of plywood samples has been investigated by thermal analysis. The result showed that EVMT increased all the limited oxygen index values of the treated samples and decreased the thermal activation energy at a high degree of degradation. Scanning electron microscope (FEI, Holland, The Netherlands) images showed that EVMT could form a protective coating, which improved the flame retardancy of plywood. 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 kinetics and lifetime estimation for polycarbonate/polymethylphenylsilsesquioxane composite

The thermal degradation behaviors of polycarbonate/polymethylphenylsilsesquioxane (FRPC) composites were investigated by thermogravimetric analysis (TGA) under isothermal conditions in nitrogen atmosphere. The isothermal kinetics equation was used to describe the thermal degradation process. The results showed that activation energy (E), in the case of isothermal degradation, was a quick increasing function of conversion (α) for polycarbonate (PC) but was a strong and decreasing function of conversion for FRPC. Under the isothermal condition, the addition of polymethylphenylsilsesquioxane (PMPSQ) retardanted the thermal degradation and enhanced the thermal stability of PC during the early and middle stages of thermal degradation. It also indicated a possible existence of a difference in nucleation, nuclei growth, and gas diffusion mechanism in the thermal degradation process between PC and FRPC. Meanwhile, the addition of PMPSQ influenced the lifetime of PC, but the composite still met the demand in manufacturing and application.     

硅酸盐阻燃木材的阻燃性能和热性能研究

通过二次浸渍工艺获得了硅酸盐阻燃木材样品,通过极限氧指数(LOI)测试了样品的阻燃性能,通过热分析结合扫描电子显微镜(SEM)研究了样品的热降解过程。结果表明:通过二次浸渍工艺可获得阻燃性能优良的阻燃木材,过渡金属硅酸盐可有效的催化木材第二阶段的降解反应,促进炭的生成,还可以在高温下形成熔体覆盖在剩炭的表面,有效提高剩炭的稳定性,同时隔绝可燃性气体的逸出,避免热量和O2的进入,使木材具有良好的阻燃性能。     

Thermal degradation of new copolymers from pyromellitic anhydride

A series of new copolyimides has been synthesized from pyromellitic anhydride. Copoly(imide esters) and copoly(imide amides) were synthesized from bis(N-methylcarboxychloride)pyromellitimide with diols and amines, respectively. One copoly(imide amine) was obtained from bis(N-allyl)pyromellitimide and piperazine via the Michael reaction. The thermal degradation of the copolymides obtained was studied by direct pyrolysis mass spectrometry. Our results show that a selective β-CH hydrogen transfer reaction occurs in copoly(imide esters) containing 1,3-propyl and 1,6-hexane diols, while an intramolecular ester exchange process takes place in copoly(imide ester) with a neopentylglycol moiety. Copoly(imide amide) containing 1,6-hexane diamine decomposes by an N-H hydrogen transfer process, although extensive crosslinking is observed, while that containing piperazine decomposes by an -CH hydrogen transfer. In contrast, copoly(imide amine) undergoes a very selective depolymerization process, yielding bis(N-allyl)pyromellitimide and piperazine.     

Thermal degradation kinetics of para‐substituted poly (styrene peroxide)s in solution

The thermal degradation of three polymeric peroxides of styrene monomers with substituents in the para position was studied at various temperatures (65, 75, 85, and 95°C). A continuous distribution model was used to evaluate the rate coefficients for the random‐chain and chain‐end scission degradation from the evolution of molecular weight distributions with time. The activation energy determined from the temperature dependence of the rate coefficients was in the range 18–22 kcal mol^?1. This result suggests that the thermal degradation of polyperoxide is controlled by the dissociation of the O—O bonds in the polymer backbone. The thermal stability for poly(p‐methylstyrene peroxide) lies in between that of poly(p‐tert‐butylstyrene peroxide) (highest) and poly(p‐bromostyrene peroxide) (lowest). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 957–961, 2002     

Thermal degradation of flax and jute fibers

The thermal degradation of jute and flax fibers under temperatures between 170 and 210°C for a maximum of 120 min was studied in detail. This article will analyze the effects of the thermal exposure on mechanical properties (tenacity) as well as on fiber fine structure (degree of polymerization and degree of crystallinity). It was found that temperatures below 170°C only slightly affects fiber properties, while temperatures above 170°C significantly dropped tenacity and degree of polymerization. Because of chain scissions, a slight increase in degree of crystallinity was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1417–1422, 2001     

高效干燥设备在无机盐生产中的应用

目前中国无机盐行业采用炕式烘干、箱式干燥、隧道窑干燥等传统干燥工艺及设备，能耗高，劳动强度大，环境污染严重，产品易被污染，质量不稳定。选用高效、密闭、连续的带式串闪蒸、桨叶式串闪蒸、双螺旋串盘式等二级干燥工艺及设备、链式层干机、组合式干燥机、旋转列管式干燥机及喷雾干燥工艺和设备等新型干燥设备，改造传统工艺及设备，提升无机盐生产中干燥装置水平，以达到节能降耗，提升产品质量水平之目的。     

热塑性弹性体热寿命和热降解动力学研究

用热重分析法研究苯乙烯-二烯烃-苯乙烯三嵌段共聚物（SIS，SBS和SI／BS）的热降解动力学及热寿命。结果表明，SIS，SBS和SI／BS在氮气气氛下的起始热降解温度分别为499．8，630．2和582．9K，SBS的热稳定性高于SIS和SI／BS；SIS的热降解属扩散过程控制机理，SBS和SI／BS属随机成核和随后生长过程控制机理，SIS，SBS和SI／BS的热降解反应活化能分别为196．8，298．3和349．9kJ·mol^-1；SIS，SI／BS和SBS的热寿命依次延长。     

PA 1111的热降解过程和机理研究

通过热重分析研究了聚酰胺(PA)1111在N_2气氛中以不同升温速率时的热降解过程和机理。PA1111的热降解实验表明,PA 1111的热降解是一步过程,热降解温度为419.5℃。用Kinssinger和Flynn-Wall-Ozawa方法求得PA 1111的热降解表观活化能分别为239.3 kJ/mol和240.9 kJ/mol。用Coats-Redfern方法证明了PA 1111的热降解为减速机理。     

Thermal degradation study of interpenetrating polymer network based on modified bismaleimide resin and cyanate ester

Interpenetrating polymer networks (IPNs) based on different ratios of a modified bismaleimide resin (BMI/DBA) and cyanate ester (b10) have been synthesized via prepolymerization followed by thermal curing. A systematic thermal degradation study of these new BMI/DBA‐CE IPN resin systems was conducted by thermogravimetric analysis at different heating rates both in N₂ (thermal stability) and in air (thermal‐oxidative stability). The cured BMI/DBA‐CE IPN resin systems show excellent thermal stability, which could be demonstrated by 5% weight loss temperature (T_5%) ranging between 409 and 423 °C, maximum decomposition rate temperature (T_max) ranging between 423 and 451 °C, and the char yields at 800 °C ranging from 37% to 41% in nitrogen at a heating rate of 10 °C min^?1. The apparent activation energy associated with the main degradation stage of the cured BMI/DBA‐CE IPN resin systems was determined using the Kissinger method. The obtained results provide useful information in drawing correlation between thermal properties and structure. © 2003 Society of Chemical Industry     

SIS-甲基丙烯酸甲酯接枝共聚物热降解过程与热寿命研究

利用热重法研究了SIS-甲基丙烯酸甲酯接枝共聚物(SIS-PMMA)在N2气氛条件下以不同升温速率时的热降解动力学及其热寿命。确定了热分解温度与升温速率的关系，求得了热分解过程的表观活化能，得到了不同失重率时的热寿命方程，计算出标题化合物在不同温度下的寿命。     

Thermal oxidative degradation kinetics of PP and PP/mg (OH)2 flame‐retardant composites

The thermal stability and thermal oxidative degradation kinetics of polypropylene (PP) and flame‐retardant PP composites filled with untreated and treated magnesium hydroxide (MH) in air were studied by thermogravimetric analysis (TGA). The effect of the heating rate in dynamic measurements (5°C–30°C/min) on kinetic parameters such as activation energy was also investigated. The Kissinger and Flynn–Wall–Ozawa methods were used to determine the apparent activation energy for the degradation of neat PP and flame‐retardant PP composites. The results of TGA showed that the addition of untreated or treated MH improved the thermal oxidative stability of PP in air. The kinetic results showed that the apparent activation energy for degradation of flame‐retardant PP composites was much higher than that of neat PP, suggesting that the flame retardant used in this work had a great effect on the mechanisms of pyrolysis and combustion of PP. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1978–1984, 2007     

Thermal degradation and morphological studies on cotton cellulose modified with various arylphosphorodichloridites

Cellulose arylphosphonate compounds have been synthesized and investigated by the kinetics of thermal degradation by thermogravimetry (TG) and differential scanning calorimetry (DSC) from ambient temperature to 600°C. Various kinetic and thermodynamic parameters such as energy, entropy and free energy of activation have been obtained from TG curves using the Broido method and transition state theory. The high values of enthalpy change (1016 and 1025 J g^?1) of decomposition and oxidation reactions corresponding to the last two exotherms of the DSC curves of cellulose are decreased to a greater extent in the case of cellulose arylphosphonate compounds. The values of activation energy for the decomposition stage of cellulose arylphosphonate compounds lie in the range 25–49 kJ mol^?1 and are found to be lower than that of pure cellulose, namely 165 kJ mol^?1 in air atmosphere. Scanning electron micrographs of phosphorylated cotton cellulose and chars show furrowed and fractured surfaces although the morphology of the original fibres remains largely unchanged. Furthermore, higher char yields of cellulose derivatives leads to the conclusion that such derivitisation may give rise to flame‐retardant treatments for cellulosic materials. Copyright © 2004 Society of Chemical Industry     

桉木光诱导氧化降解研究

本文研究了尾叶桉（Eucalyptusurophylla）木粉在光照射下其木素和多聚糖的变化行为．研究表明，在光照射下木素及木素结构单元中的甲氧基含量降低，多聚糖含量降低，铜价升高．UV分析可知，木素光降解产物中羰基或与苯环共轭的乙烯双键结构较多．经GC－MS分析鉴定出尾叶桉SCMP浆40种低分子量木素光氧化降解产物，其中丁香基型占58．10％，愈疮木基型占18．75％，其它占21．93％，主要降解产物包括丁香醛、2－羟基－3－丁香基丙酸、3，4－二羟基苯甲酸,2－丁香基乙醇、丁香酸、丁香酸和香兰素等.另外也研究了光降解过程中木素自由基变化行为。ESR分析测定表明，光照射产生的自由基在纯的氮气或二氧化碳中相对稳定，在空气或氧气中游离基迅速衰减，从而证实光诱导氧化作用是木材或富含木素化学机械浆光降解的重要作用。     

Thermal and fire degradation of recycled and polluted polypropylene‐based materials

In this study, the effect of processing cycles and two pollutants (engine oil (HM) and ethylene glycol (EG)) on the thermal and rheological properties of polypropylene‐based materials (108MF97 and 7510) has been studied. It was investigated if polymers coming from bumper face bar could keep their properties and can be reused after recycling. The different results demonstrate that the two polymers that were polluted and recycled do not show any decrease of their intrinsic properties. Moreover, for one of the two polymers (108MF97), the presence of engine oil enables to increase the thermal stability and reaction to fire. Finally, it appears that the reuse of such polymers is possible. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal and microwave‐assisted oxidative degradation of poly(ethylene oxide)

The kinetics of the thermal and microwave‐assisted oxidative degradation of poly(ethylene oxide) were determined with potassium persulfate as the oxidizing agent. Gel permeation chromatography was used to determine the variation of the molecular weight with time. The degradation was studied as a function of the temperature and persulfate concentration, and it was found that the degradation rate increased with the temperature and concentration of persulfate. Continuous distribution kinetics were used to determine the rate coefficients for the degradation process, and the activation energies were obtained. The results indicated that the microwave‐assisted process had a lower activation energy of 10.3 kcal/mol, whereas that of the thermal degradation was 25.2 kcal/mol. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2090–2096, 2005     

The effect of fibre content on the thermal and fire performance of polypropylene–glass composites

Thermoplastic composites demand constant improvements in fire retardant and mechanical properties to fulfil their full market potential, especially in demanding sectors such as rail, aerospace and infrastructure, where fire performance is critical. The aim of this work is to understand the effect of reinforcing fibres on the flammability of polypropylene–glass (P‐G) composites and the means of improving their fire performance in a cost‐effective manner. A number of P‐G composites with 0%, 10% and 20% (w/w) glass fibres were prepared using short length glass fibres. The effect of fibre content on the thermal stability, flammability and mechanical performance of the P‐G composites without and in the presence of conventional fire retardants was studied. It was observed that while the presence of glass fibre lowered down the limiting oxygen index value of the composite, the rate of flame spread in a UL‐94 equivalent test was also lowered. The reduction in limiting oxygen index is due to the fact that glass fibre reduces the melt dripping behaviour of polypropylene and does not let the polymer (polypropylene) move away from flame, which then burns. Cone calorimetric study indicated that the presence of glass fibre reduces the overall flammability of the composite laminate. Copyright © 2011 John Wiley & Sons, Ltd.