阻燃羊毛纤维的热性能研究

用氟锆酸钾、有机二酸处理羊毛线、用热分析、剩碳率及氧指数等分析方法对其阻燃性进行了研究,并用Kissinger方程计算热降解反应活化能。实验证明：经过阻燃处理的羊毛毛线比未经阻燃处理的羊毛毛线的剩碳率、氧指数均有所提高,热降解反应活化能和热分解温度降低。     

二氰二胺和磷酸对大豆蛋白纤维的阻燃研究

本文分别用二氰二胺、磷酸以及二氰二胺和磷酸协同体系对大豆蛋白纤维(天鹅绒,38%大豆蛋白纤维/38%棉/24%涤纶)进行阻燃整理(主要对天鹅绒制品中的大豆蛋白纤维的处理),通过极限氧指数、剩炭率、热分析和扫描电子显微镜等分析方法对其阻燃性能进行研究,并用Broido方程计算其热降解活化能的变化。结果表明:与未经阻燃处理的大豆蛋白纤维相比,阻燃大豆蛋白纤维的极限氧指数、剩炭率均有所增加;热降解起始温度降低;热降解活化能减小;剩炭较为膨胀,其中经二氰二胺和磷酸协同体系处理后的样品阻燃效果最佳。     

无机金属氧化物复合羊毛纤维的阻燃机理研究

通过热分析、剩碳率、氧指数和扫描电镜对无机金属氧化物溶胶处理后的羊毛样品的热降解行为进行了表征,并对其阻燃机理作了初步探讨。结果表明,经过阻燃处理的羊毛其氧指数、剩碳率比未处理的羊毛升高,阻燃性明显增强。     

ZnO与Al(OH)3在阻燃软PVC中的协同阻燃消烟作用

研究了ZnO和Al(OH)3复合阻燃剂对软PVC的协同阻燃消烟作用.通过热分析的方法研究了阻燃处理后的软PVC从室温到800℃的热降解过程,用Kissinger方程给出了热降解反应的活化能,通过剩炭率的测定以及用电子扫描显微镜(SEM)对燃烧后所生成炭层的观察探讨了协同体系阻燃抑烟的机理.结果表明经阻燃处理的样品具有较高的极限氧指数(LOI)、剩炭率较低的烟密度等级(SDR)和最大烟密度(MSD),与未处理的样品相比具有较好的阻燃和消烟性能.加入适量的ZnO与Al(OH)3复合使用可明显地提高软PVC的LOI和剩炭率,降低材料的SDR和MSD.ZnO的加入可改变PVC的热降解过程,使起始降解温度降低并且使反应的活化能增大,可能属于固相Lewis酸催化机理.     

ZnO与Mg(OH)_2在软PVC中的协同阻燃消烟作用

用热分析的方法研究了ZnO和Mg(OH)2复合阻燃剂对软PVC的协同阻燃消烟作用,考察了经阻燃处理的软PVC从室温到800℃的热降解过程,用Kissinger方程给出了热降解反应的活化能。通过极限氧指数(LOI)、剩炭率、烟密度等级(SDR)和最大烟密度(MSD)的测定以及用电子扫描显微镜(SEM)对燃烧后所生成炭层的观察,探讨了协同体系阻燃抑烟的机理。结果表明:经阻燃处理的样品尤其是加入适量ZnO和Mg(OH)2复合阻燃剂的样品具有较高的极限氧指数(LOI)和剩炭率、较低的烟密度等级(SDR)和最大烟密度(MSD),与未处理的样品相比具有较好的阻燃和消烟性能。ZnO的加入可改变PVC的热降解过程,使起始降解温度降低,并且使反应的活化能增大,可能属于固相Lewis酸催化机理。     

三聚氰胺和磷酸对大豆蛋白纤维的阻燃研究

用三聚氰胺和磷酸协同体系对大豆蛋白纤维（天鹅绒,38％大豆蛋白纤维／38％棉／24％涤纶）进行阻燃处理（主要对天鹅绒制品中的大豆蛋白纤维的处理）,并采用了限氧指数（LOI）、剩炭率、热分析、扫描电子显微镜（SEM）等方法对处理前后大豆蛋白纤维的阻燃性能及其热降解机理进行了研究．对比未阻燃的样品,阻燃处理后的大豆蛋白纤维的剩炭率、氧指数升高,热降解起始温度降低,阻燃性得到明显改善．     

磷-胺-醛树脂型阻燃剂处理落叶松的热分析及其动力学

将落叶松用一系列磷-胺-醛树脂型阻燃剂进行阻燃处理,所得阻燃落叶松采用热分析、锥形量热研究其热解行为,用氧指数、剩炭率、热释放速率、总热释放量等参数表征它的阻燃性能,并用Broido方程计算落叶松的动力学参数. 结果发现,阻燃落叶松氧指数、剩炭率增加,热释放速率、总热释放量降低,表明经阻燃剂处理的落叶松燃烧性降低. 落叶松经阻燃剂处理后,热解活化能降低很多,表明阻燃剂对落叶松热解具有催化作用,其主要热解阶段在低于300℃进行. 在此温度下,落叶松热解主要发生脱水、重排交联炭化反应,产生水、CO及CO2、固体残渣,可燃性气体大大降低,达到降低落叶松燃烧性的目的.     

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。     

硅酸盐对软PVC阻燃性和热性能的影响

研究了硅酸盐对软聚氯乙烯(PVC)的阻燃作用。通过热分析法研究了经阻燃处理后软PVC从室温到800℃的热降解过程;通过剩炭率的测定,结合用扫描电子显微镜(SEM)对样品燃烧后剩炭结构的观察,探讨了硅酸盐的阻燃机理。结果表明:经硅酸盐处理的样品具有较高的氧指数(OI)和剩炭率,与未处理的样品相比具有较好的阻燃性能。硅酸盐的加入可改变PVC的热降解过程,使起始降解温度降低,最大失重速率加快,硅酸盐对软PVC的阻燃主要是由于凝聚相的Lewis酸催化作用以及高温下生成的玻璃体对剩炭的保护作用造成的。     

阻燃大豆蛋白纤维的热性能研究

为了提高阻燃性,用四溴酞酐(TBPA)加有机二酸体系对大豆蛋白纤维进行了阻燃处理,然后用极限氧指数(LOI)、剩炭率表征了它的阻燃性能,用热分析和扫描电子显微镜研究了它的热性能。结果表明:与纯大豆蛋白纤维相比,阻燃处理后的大豆蛋白纤维的极限氧指数和剩炭率提高,热分解起始温度降低,阻燃性能得到了明显改进。     

Kinetics of wood phenolysis in the presence of HCL as catalyst

Monarch birch wood (Betula maximowiczina Regel) wastes were phenolated in the presence of HCl as a catalyst at 60–150°C for various reaction times. Typical kinetic parameters along with percent reacted wood and phenol were determined by using kinetic models. In addition, according to the transition‐state theory the activation parameters of wood phenolysis was determined. The percent reacted wood wastes depicted that about 90% of the wood could be liquefied into phenol at a temperature of 150°C. However, about 30% of phenol was found to react with wood components. The kinetic studies showed that wood phenolysis with HCl catalyst at 60–150°C obviously followed a bimolecular type of second‐order reaction. Activation energy was found to be 13.438 kJ mol^?1 from an Arrhenius plot. Furthermore, the findings related with activation enthalpy showed that the wood phenolysis had dominantly endothermic reaction nature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1098–1103, 2002     

A KINETIC STUDY OF SULFURIC ACID-CATALYZED LIQUEFACTION OF WOOD INTO PHENOL

The powders of monarch birch wood (Betula maximowiczina Regel) were liquefied into phenol using sulfuric acid as a catalyst at various temperatures and reaction times. Typical kinetic parameters of the degrading reaction of wood in the presence of phenol and the acid were determined using typical kinetic models. In addition, the activation parameters of the liquefaction of wood were determined according to transition-state theory. The results of showed percent liquefied wood that about 100% of the wood could be liquefied into phenol at a temperature of 150°C for about 2 h. However, about 68% of phenol was found to react mainly with wood components along with sulfuric acid and phenol itself. The kinetic studies showed that the liquefaction of wood into phenol using sulfuric acid obeyed a bimolecular type second-order reaction and Arrhenius law. The activation energy of the liquefaction was 68.5 kJ mol^-1. Furthermore, the findings related with activation enthalpy showed that the liquefaction of wood possessed a primarily endothermic reaction nature.     

A KINETIC STUDY OF SULFURIC ACID-CATALYZED LIQUEFACTION OF WOOD INTO PHENOL

The powders of monarch birch wood (Betula maximowiczina Regel) were liquefied into phenol using sulfuric acid as a catalyst at various temperatures and reaction times. Typical kinetic parameters of the degrading reaction of wood in the presence of phenol and the acid were determined using typical kinetic models. In addition, the activation parameters of the liquefaction of wood were determined according to transition-state theory. The results of showed percent liquefied wood that about 100% of the wood could be liquefied into phenol at a temperature of 150°C for about 2 h. However, about 68% of phenol was found to react mainly with wood components along with sulfuric acid and phenol itself. The kinetic studies showed that the liquefaction of wood into phenol using sulfuric acid obeyed a bimolecular type second-order reaction and Arrhenius law. The activation energy of the liquefaction was 68.5 kJ mol^?1. Furthermore, the findings related with activation enthalpy showed that the liquefaction of wood possessed a primarily endothermic reaction nature.     

松木脱脂行为的热重研究

本文应用热重分析法研究了松木在10℃.m in-1升温速率下,30~700℃的热分解过程,分析了每个阶段的化学物理变化,并比较了干燥脱脂和丙酮脱脂后松木的热解行为,找出高温脱脂的最佳温度为180~200℃。利用松木热重分析曲线求得松木热解脱脂反应为一级反应,表观活化能为93.18KJ.mol-1,这些数据可为松木的脱脂与防火研究提供参考。     

Effect of Wood Fibers on the Rheological and Mechanical Properties of Polystyrene/Wood Composites

The effects of wood fibers on the rheological and mechanical properties of polystyrene/wood (PS/wood) composites were investigated. The composites with different ratios of PS and wood were prepared by means of internal mixer and, additionally, two different sizes of the wood particles were used, such as ～100 and ～600 µm. The rheological properties were studied using capillary rheometer, apparent shear rate, apparent shear stress, apparent viscosity, power law index, and flow activation energy at a constant shear stress were determined. The rheological results showed that the shear stress–shear rate variations obeyed a power law equation, and the composites exhibited shear thinning. The flow activation energy of the composites increased with the addition of wood particles. Mechanical results showed that stress at break of the composites was higher than that of pure PS, whereas the strain at break and impact strength of the composites were lower than that of PS. In addition, the mechanical properties of the present composites were improved when the small size of wood particles were incorporated.     

Monitoring the curing of furan resins through the exothermic heat of reaction

The curing reaction of furan resins was monitored through the exothermic heat of reaction by means of a simple technique. p-Toluene sulphonic acid dissolved in acetone was used to catalyse the curing reaction. A ‘cure rate index’, defined as the maximum temperature rise per unit time per unit mass of the resin, was used as a measure of the rate of cure. The index value increases exponentially with the catalyst concentration. Interestingly, for the same catalyst concentration the index value also increases significantly with the period of ageing of the catalyst solution. A method is developed for deriving the activation energy for the curing reaction from the exothermic heat data for non-isothermal cure. The activation energy is found to increase with resin viscosity and to decrease exponentially with increasing catalyst concentration. Quantitative expressions are derived relating activation energy with catalyst concentration.     

The fire retardance and endurance of functionally graded wood in the case of the heat-compressed treatment method

The behaviour of wood with the heat-compressed treatment method was evaluated. Fire retardance and endurance of wood treated with basic nitrogen compounds and phosphoric acid were much improved by the compressed method using a hot press. In this way, the concentration of chemical contents and the density of wood were raised at the surface of the treated wood and it increased the specific gravity of the treated wood as a whole. It was recognized that the increase of specific gravity improved fire retardance and endurance, and fire endurance of wood was indicated by the equation of addition of chemicals and specific gravity. It is more effective to increase the specific gravity of wood at the surface to improve fire endurance. Wood treated with chemicals showed a high limiting oxygen index in proportion to the increase in the addition of chemicals regardless of the treatment method, and high fire endurance was not always accompanied by a high limiting oxygen index. © 1998 John Wiley & Sons, Ltd.     

Differential scanning calorimetry characterization of urea–formaldehyde resin curing behavior as affected by less desirable wood material and catalyst content

Differential scanning calorimetry was applied to investigate the curing behavior of urea–formaldehyde (UF) resin as affected by the catalyst content and several less desirable wood materials (e.g., wood barks, tops, and commercial thinnings). The results indicate that the reaction enthalpy of UF resin increased with increasing catalyst content. The activation energy and peak temperature of the curing UF resin generally decreased with increasing catalyst content at lower levels of catalyst content. However, with further increases in catalyst content, the changes in the activation energy and peak temperature were very limited to nonexistent. The hydrolysis reaction of the cured UF resin occurred during the latter stages of the curing process at both lower level (<0.2%) and higher level (>0.7%) catalyst contents. This indicates that there existed an optimal range of catalyst content for the UF resin. The curing enthalpy of the UF resin decreased with increasing wood raw materials present due to the effect of diffusion induced by the wood materials and the changes in the phase of the curing systems. This suggests that the curing reactions reached a lower final degree of conversion for the wood–resin mixtures than for the UF resin alone. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2027–2032, 2005     

Influence of carbonization conditions on the gasification of acacia and eucalyptus wood chars by carbon dioxide

Gasification rates of cubic shaped acacia and eucalyptus wood chars were measured thermogravimetrically in a carbon dioxide atmosphere at temperatures in the range 810–960 °C. The effects of wood species and carbonization conditions, such as temperature, heating rate and soaking time, were determined. Both reactivity and the activation energy for the gasification of wood chars were found to be strongly influenced by the carbonization conditions employed during their preparation and wood type. The reactivities of both the acacia and eucalyptus wood chars decreased with increasing preparation temperature; while the activation energy for their gasification increased. Slow carbonization (heating rate: 4 °C min⁻¹) led to the production of wood chars having lower reactivities and higher activation energies than those of the wood chars prepared under rapid carbonization (heating rate: 30 °C min⁻¹) at the same temperature. With increasing soaking time, at carbonization temperatures of 800 and 1000 °C, the reactivity of resulting wood chars was reduced. The results also show that the reactivities of acacia wood chars are higher than those of similarly prepared eucalyptus wood chars.     

Wood-induced catalytic activation of PF adhesives autopolymerization vs. PF/wood covalent bonding

The reaction of polycondensation of phenol-formaldehyde (PF) resins in the presence of wood was confirmed to have a lower energy of activation than of the PF resin alone. Under the low temperature and short curing times characteristic of the application of PF resins as thermosetting wood adhesives DSC, TGA, chemical kinetics, and IR of PF resins and relevant model compounds were carried out. These indicated that two effects appear to be present when a PF resin cures on a wood surface, both induced by the polymeric constituents of the substrate, namely carbohydrates and lignin. These appear to be (1) the catalytic activation of the resin self-condensation induced particularly by carbohydrates such as crystalline and amorphous cellulose and hemicelluloses and (2) the formation of resin/substrate covalent bonding, particularly in the case of lignin. The first appears to be, by far, the major cause of the lowering of the activation energy of PF resins curing. The contribution of the second has been found to be very small and often negligble under the conditions pertaining to thermosetting wood adhesives applications. Molecular mechanics results appear to indicate that the marked catalytic activation of PF resins autocondensation and curing appears to be induced by the strong set of PF adhesive/substrate secondary forces interactions which appear to weaken bonds which, by cleavage, lead to PF resins autocondensation. © 1994 John Wiley & Sons, Inc.