Study of oxidation of pitch fibres

The studies conducted led to the following conclusions: effective oxidation of pitch fibres begins at a temperature slightly above the flow temperature of the starting pitch; oxidation is limited by diffusion of gaseous products so that it is expedient to use initial fibres with a diameter of 10 µm and to conduct the process in conditions of effective blowing with air.Translated from Khimicheskie Volokna, No. 1, pp. 20–21, January–February, 1995.     

Increasing the spinning stability of acrylic fibres

There are two regions of elevated spinning stability separated by a region of unstable jet formation caused by deformation resonance on the spinning stability curves characterizing the maximum deformation of the jets on the distance to their solidification point. Increasing the concentration of solvent (DMAA) in the spinning bath increases the distance to the solidification point and greater expansion of the jet, intensifying the deformation resonance, detected by an increase in the nonuniformity of the linear density of the filaments. With a concentration of solvent of 80% and higher, the solidification point is so far from the spinneret that it does not affect jet expansion; the deformation resonance phenomenon disappears, manifested by an increase in the deformability of the jet and a decrease in the nonuniformity of the linear density of the filaments. Increasing the spinning bath temperature moves the solidification point closer to the spinneret and suppresses deformation resonance, which also increases the deformability of the jet and decreases the nonuniformity of the linear density of the filaments. All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated fromKhimicheskie Volokna, No. 5, pp. 16–19, September–October, 1999.     

The thermal memory of acrylic fibres

The dyeing operation produces significant decreases in the differential solubility of acrylic fibres with different percentage of relaxation. It has also been observed that the solubility differences found between substrates having different relaxation properties are largely preserved after a blind dyeing treatment has been carried out. The differential solubility technique using a mixture of dimethylformamide and water has been used to characterise their structure, and it has been found that acrylic fibres possess a good thermal memory.     

Kinetics of solvent-assisted dyeing of acrylic fibres

The kinetics of dyeing acrylic fibres with cationic dyes in the presence of small amounts of the solvents ethylene carbonate, propylene carbonate, nitromethane and iso-amyl alcohol has been studied. The time of half-dyeing was taken as a measure of the rate of dyeing, which was found to decrease with increasing concentration of the solvent in the dyebath. A linear correlation was observed between the rate of dyeing and the change in glass transition temperature of the fibre.     

丙烷选择氧化制丙烯酸的研究

本文通过对丙烷选择氧化制丙烯酸的热力学和动力学的研究,提出了丙烷选择氧化制丙烯酸反应的可行性与存在的难题。解决这两大难题的关键是催化剂的选择,文中也简单介绍了目前由丙烷选择氧化制丙烯酸反应的三大体系催化剂。     

Plasticisation and thermal characterisation of acrylic fibres

The effect of a range of dyebath additives on the thermal behaviour, swellability and second-order glass transition temperature of an acrylic fibre (Leacril) has been studied in an attempt to correlate fibre properties with dyebath conditions. Glass-transition temperature was determined using filament length extension, differential scanning calorimetry and dye uptake techniques.     

MgAlON结合耐火材料的氧化动力学研究

借助于微量热天平 ,通过非等温氧化实验和在不同温度下进行等温氧化实验 ,研究了MgA lON结合耐火材料的氧化行为和氧化动力学。研究结果表明 ,MgAlON结合刚玉耐火材料比MgAlON结合尖晶石耐火材料易于氧化。MgAlON结合尖晶石耐火材料的氧化规律为化学反应速度控制阶段 -混合控速阶段 -扩散速度控制阶段。而MgAlON结合刚玉耐火材料试样的氧化规律为化学反应速控-扩散速控。     

煤矿中硫铁化合物的氧化动力学研究

硫铁化合物氧化放热是引发煤炭自燃的原因之一,运用XRD、TG-DSC技术分析硫铁化合物的热分解过程和非等温热分解机理。研究表明,硫铁化合物分解包括3个阶段:在179.1²87.75℃内逐步进行物相转化,403.5287.75℃内逐步进行物相转化,403.5⁴93.75℃内开始FeS_2的氧化热解,611.65493.75℃内开始FeS_2的氧化热解,611.65⁷92.25℃内发生硫酸盐(或亚硫酸盐)逐步分解,热解失重达到最大值。运用Friedma法、Kissinger法、Starink法对非等温动力学数据进行分析,3个阶段的表观活化能分别是96,174,230 k J/mol。各阶段样品稳定性逐渐提高,为硫铁化合物自燃的综合判据提供依据。     

煤矿中硫铁化合物的氧化动力学研究

硫铁化合物氧化放热是引发煤炭自燃的原因之一,运用XRD、TG-DSC技术分析硫铁化合物的热分解过程和非等温热分解机理。研究表明,硫铁化合物分解包括3个阶段:在179.1~287.75℃内逐步进行物相转化,403.5~493.75℃内开始FeS_2的氧化热解,611.65~792.25℃内发生硫酸盐(或亚硫酸盐)逐步分解,热解失重达到最大值。运用Friedma法、Kissinger法、Starink法对非等温动力学数据进行分析,3个阶段的表观活化能分别是96,174,230 k J/mol。各阶段样品稳定性逐渐提高,为硫铁化合物自燃的综合判据提供依据。     

Halochromism of acrylic fibres dyed with some disperse dyes

Anomalous dyeing behaviour has been found when regular acrylic fibre treated in hydrochloric acid, in which the sulphonic acid group was present entirely in the acid form, was dyed in neutral condition with azo and anthraquinone disperse dyes. In the very early stages of dyeing there was an abnormally high degree of dye exhaustion, with bathochromic (azo) or hypsochromic (anthraquinone) colour changes on the fibre. These phenomena gradually disappeared after prolonged dyeing, with normal adsorption equilibria and colours eventually being obtained. The results were explained on the basis of protonation by the sulphonic acid groups of treated fibre which occurs at the azo nitrogen or the amino nitrogens of the substituents in the 1 — or 1,4-positions of anthraquinone. The normal adsorption equilibria after prolonged dyeing was attributed to hydrolysis of the cyano side group to form carboxylic acid. This produces ammonia to liberate neutral dye from the protonated dye cation adsorbed electrostatically by the sulphonic acid anion of the treated fibre.     

ZrB_2-刚玉莫来石复合材料氧化动力学的研究

推导了复合材料的氧化动力学模型,并用实验数据予以验证。找出了刚玉莫来石对ZrB2材料抗氧化性的影响规律,并对材料的氧化表面及氧化断口的显微结构进行了分析。     

纳滤膜脱除纺丝洗涤废水中非挥发组分的研究

采用纳滤膜进行了脱除干法腈纶纺丝洗涤废水中非挥发组分(NV)的试验.分析了压力、流量、温度和膜污染等影响纳滤过程的因素,并考察了原水和透过液中的TOC、电导率和NV.实验结果表明,经纳滤处理的透过液中TOC为14 g/L、电导率为60μS/cm、NV质量分数为0.07%,DMF 94%以上透过纳滤膜,NV去除率＞95%.同时,用质量分数0.1%的NaOH溶液冲洗就可使纳滤膜的纯水通量恢复率达到85%.     

Thermal properties of nylon 6 fibres grafted with acrylic monomers

Thermal Properties of methyl methacrylate (MMA), ethyl methacrylate (EMA) and n-butyl methacrylate (n-BMA) grafted onto nylon 6 fibre with various graft levels were investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) and the results compared with that of parent nylon 6 fibre. It was found that the initial decomposition temperatures (IDT) of the grafted samples were lower than that of the parent nylon 6 fibre. On the other hand with all the three monomers, there was an increase in overall thermal stability followed by subsequent decrease with increase in the graft level. Among the grafted samples both the IDT and IPDT (initial procedural decomposition temperature) followed the order MMA-g nylon > EMA-g nylon < n-BMA-g nylon Differential thermal analysis shows a depression in glass transition temperature (T_g) as well as in melting temperature (T_m). In the case of the MMA and EMA grafted samples, the depression is small over a wide range of graft level. In the case of the n-BMA grafted samples, the depression is higher. A wide melting range was obtained in the grafted samples. Flammability studies also showed that with an increase in the graft level as well as an increase in the alkyl chain the ease of flammability increased as expressed by limiting oxygen index (LOI) values. The possible reasons for the phenomena occurred have been discussed.     

活性炭强化臭氧氧化丙烯酸及酯废水的研究

生化后的丙烯酸及酯废水COD为550 mg/L,需进行深度处理才能达标排放。研究了活性炭强化的臭氧氧化工艺对该废水的处理效能,考察了废水碱度、活性炭装填高度、臭氧浓度和废水柱外循环流量对COD去除率的影响。实验结果表明,在最佳条件下反应2 h,废水COD可降至35 mg/L,达到《污水综合排放标准》(GB 8978—1996)中的一级标准要求。     

仲丁基苯液相氧化反应动力学

非催化条件下仲丁基苯（SBB）液相氧化制备过氧化氢仲丁基苯（SBBHP）是生产苯酚和甲乙酮的关键步骤。基于烃类链式自由基反应机理,分别建立了氧充足和限氧条件下SBB氧化动力学模型,模型包含了反应物SBB、主产物SBBHP、副产物苯乙酮（ACP）、2-苯基-2-丁醇（PBO）等。通过分别拟合不同条件下的实验数据（388~403 K）,得到了相应的基元反应速率常数和活化能。结果表明,由于空间位阻效应,主反应生成SBBHP的活化能大于异丙苯（IPB）生成过氧化氢异丙苯（CHP）的活化能。连续实验进一步验证了动力学模型的可靠性。相关研究结果可用于仲丁基苯液相氧化过程的设计和优化,并且基元反应相关结果有利于丰富对烷基芳烃氧化反应机理的认识。     

Mechanism of the thermal transformations of polyacrylonitrile fibres in oxidation

Conclusions 1. The mechanism of the physicochemical transformations of PAN fibres which take place in an atmospheric oxygen medium at 200°C has been studied, and the time intervals for their occurrence have been established.2. It has been found that on heat treatment of PAN fibres for 3–4 h, dehydration reactions mainly take place; and on increasing the time from 3 to 9 h, mainly cyclization reactions take place. Intermolecular condensation reactions, which lead to the formation of polynuclear planar aromatic structures, take place after 11–12 h of heat treatment.3. A new approach has been proposed for interpreting DTA data, based on analysis of the components of the DTA curve equation, and also DTA parameters for control of the process of thermooxidative treatment of PAN fibres.4. It has been found by the XSA method that the cross-linking process leads to the formation of two-dimensional structures. An x-ray analysis figure has been proposed which makes it possible to discern the time intervals for occurrence of cross-linking.Translated from Khimicheskie Volokna, No. 5, pp. 8–11, September–October, 1993.     

大庆某低渗轻质油藏注空气低温氧化反应动力学研究

轻质油藏注空气提高采收率的机理之一是在油藏中发生低温氧化反应,低温氧化反应进行的程度将对油藏注空气开发的可行性产生决定性的影响。通过在RUSKA2370-601PVT筒中进行的大庆某低渗油田原油与空气恒温恒压氧化反应实验数据,获得轻质油藏注空气低温氧化反应动力学参数为:原油氧化反应为零级反应;21 MPa,87℃时氧化反应的速度常数KO2为1.2255×10-4mol/(mL.h),21 MPa,127℃时氧化反应的速度常数KO2为7.0101×10-4mol/(mL.h),原油样品的阿仑尼乌斯活化能Ea为52.1 kJ/mol。