溶剂处理对沥青球氧化稳定化的影响研究

研究了溶剂处理时间、温度等条件对石油沥青球和煤沥青球的收率、氧化破损率及氧化稳定化效果的影响,结果表明：在室温下用烷烃类浸泡沥青球,可以有效地除去沥青球中的萘和轻组份,打通氧气向内扩散的通道,缩小沥青球表面和呐部氧化反应程度差别,促进沥青球的快速均匀不熔化;提高溶剂处理温度,容易刻蚀球表面,影响球的外观和强度;较低软化点的石油沥青球比煤沥青球比煤沥青球表面更易于刻蚀更难于氧化稳定化。     

石油沥青对乳化法煤沥青基炭微球的改性机理

通过在煤焦油沥青中添加石油沥青获得沥青甲苯胶体溶液,然后与聚乙烯醇(PVA)的甘油溶液乳化,制备了煤沥青基炭微球.为了阐明沥青在甲苯中的溶解性及其与PVA中憎水的亚甲基亲合力对于微球形成的影响,在煤沥青中添加了不同比例的与PVA中憎水的亚甲基更具亲合力的石油沥青,建立了一个微球成形机理的模型.研究发现,添加石油沥青可以促进乳化液中沥青分子与分散剂界面上表面活性剂分子的取向稳定性,从而明显改善沥青微球的球形度.石油沥青的添加降低了混合后沥青的软化点,为使沥青微球的软化点高于空气氧化始温,需要选择适当的添加比例.     

氧化处理对煤沥青基中间相炭微球自烧结炭块性能的影响

采用氧化处理得到自烧结性良好的中间相沥青炭微球（MCMB），通过热压成型、炭化等工艺制备了高性能的各向同性炭块，经300℃氧化45min后的中间相炭微球热压成型后1000℃炭化1h制得的炭块密度为1.64g/cm^3、弯曲强度达99.5MPa，详细研究了不同氧化温度和时间对各向同性炭块的密度，弯曲强度、体积收缩率、断面形态等的影响，元素分析、XPS等测试分析结果表明：随着氧化程度的加深，MCMB中氧含是逐渐增加，H、C含量逐渐降低，H/C比也逐渐降低，微球中的塑性组分β树脂被氧化成羟基、羰基、羧基等含氧官能团，微球的芳香度增加，从而降低了中间相沥青炭微球的塑性流动性。     

高性能中介相沥青基碳微球及碳片

综述了继中介相沥青基碳纤维之后新举起的中介相沥青基碳微球及碳片这两大类高级碳材料的制备方法，结构特征，优异性能和重要用途指出中介相尖青基碳微球具有高达５０００ｍ＾２／ｇ的比表面积和很高的表面活性，     

不同KOH配比对中间相活性炭微球结构形态的影响

为了制备中孔含量高的高比表面积活性炭微球，以KOH为活化剂，在850℃下对中间相沥青微球（MMB）进行了活化处理，考察了不同KOH配比对活性炭微球孔结构及其表面形态的影响，并对KOH活化中间相沥青微球的反应机理进行了初步探讨，研究结果表明：随着KOH配比增加，活性炭微球总孔容和中孔孔容含蛳分别达到最高值，进一步增加KOH配比二者均呈下降趋势；KOH配比为8时制备的活性炭微球具有最高的总孔容和和比表面积，同时具有较高的中孔孔容含量；KOH配比为10时，活性炭微球的总孔容和比表面积下降，但中孔孔容达到最高值；随着KOH配比的增加，活性炭微球尺寸变小，由圆形变为椭圆形，然后变为较小圆颗粒。     

添加剂对煤沥青的改性作用及沥青焦性能的影响

通过考察添加剂加入量与煤沥青的甲苯不溶物含量、软化点、析焦量以及所得沥焦的抗氧化性和石墨化活性的关系,探讨了添加剂对煤沥青的改性作用及其对沥青焦性能的影响。实验结果表明：在煤沥青中加入适当的添加剂可提高煤沥青的甲苯不溶物含量和析焦量,加入添加剂的煤沥青炭化后所得沥青焦的抗氧化性和石墨化活性均得到显著提高,但氧化残余物含量有所上升。该沥青焦经2300℃高温石墨化处理后仍表现出优良的抗氧化性。     

甲基萘经HF／BF3催化制备中间相沥青

一、引言人们已制备出制造炭纤维用的优质前驱体中间相沥青。据信,环烷基和甲基有利于纺丝和稳定化。已经证明,纯的芳香烃在HF/BF_3的帮助下,能以非常合理的成本制得优质中间相沥青。从萘得到的沥青带有大量的环烷氢,它们能降低其软化点并增强其稳定化反应性。本工作研究了由甲基萘催化合成中间相沥青的过程,其目的是弄清甲基基团对芳香     

石墨微球的制备及化学修饰

采用化学气相沉积（CVD）法以脱油沥青（deoiled asphalt，DOA）为碳源制备出碳微球，对碳微球进行了真空热处理，运用硬脂酸对石墨微球进行表面修饰，并研究了硬脂酸修饰后石墨微球作为润滑油添加剂的分散性和稳定性。采用X射线衍射（XRD），场发射扫描电镜（SEM），高分辨透射电镜（HRTEM）分析了石墨微球的晶体结构和形貌，结果表明所制备的碳微球纯度很高，粒径均匀（500nm），真空热处理后显著提高了碳微球的石墨化程度，使碳微球转变为石墨微球。傅立叶红外（FT—IR）实验证明，通过酯化反应石墨微球能够被硬脂酸包覆；显著提高了石墨微球在润滑油中的分散性和稳定性。     

乳液法制备中间相炭微球的研究

为制备高性能中间相炭微球(MesocarbonMicrobeads,简称MCMB),选用三种不同中间相含量的石油渣油沥青为原料(中间相体积含量:PP185%,PP290%,PP3100%),采用乳液法制备中间相沥青微球(MesophasePitchMi crobeads,简称MPMB),再经预氧化和炭化处理,制得圆整度好、收率高、球径分布窄的中间相炭微球。利用扫描电子显微镜(SEM)考察了MPMB的微观形貌,同时还利用激光粒度分析仪测定了MPMB的粒度分布。研究了乳液法制备MPMB的影响因素,研究结果表明:(1)耐高温硅油适宜作为乳液法的导热分散介质;(2)不同中间相含量的沥青制备微球时有其适宜的处理温度和时间(PP1:320℃,30min;PP2:330℃,30min;PP3:355℃,30min),且制得的微球收率(收率:PP1相似文献   

添加松香对中间相炭微球制备的影响

以中温煤沥青为原料,松香为添加剂,通过热缩聚合法制备中间相炭微球。采用FT-IR、SEM、偏光显微镜等对所得产物进行表征,研究了松香对中间相炭微球制备的影响。研究表明松香的加入能有效限制沥青的过度聚合,不仅促进中间相炭微球的成核和生长,而且在很大程度上防止中间相炭微球的融并;当松香添加量为10%(质量分数)时,改性煤沥青经450℃热解2h可制备出球形度好、粒径均匀的中间相炭微球,其平均粒径为15.3μm,收率达44.1%。     

Oxidation properties of mesophase pitch prepared by a heterogeneous nucleation method

Mesophase pitches prepared by a heterogeneous nucleation method from various mixtures of coal tar-derived isotropic pitch and petroleum-derived mesophase pitch (MP-P) were oxidatively stabilized, and the dependence of chemical reactivity and stabilization rate on their chemical structure was investigated. The rate and amount of oxygen uptake of the mesophase pitch fibres, revealed by thermogravimetry, increased under given conditions of oxidation with the amount of added MP-P, but the rate of stabilization showed a reverse trend. The lower chemical reactivity of coal tar-derived mesophase pitch (MP-C) appears to induce a slower rate of oxygen uptake, while the higher content of pyridine-insoluble fraction and higher aromaticity of MP-C may result in a lesser content of oxygen being required for stabilization, as compared with MP-P.     

同步氢化/热缩聚法制备中间相沥青的工艺研究

系统地研究了在氢化剂量固定情况下,反应温度与时间对同步氢化/热缩聚法所制得的中间相沥青(MP)性质的影响,并制得了可纺MP。研究表明反应时间同为4h时,MP的软化点和不溶分含量随反应温度的提高而升高;偏光结果显示,低温产物为中间相小球和各向同性基质的混合物,高温产物为连续中间相。反应温度同为410℃时,MP软化点和不溶分含量均随反应时间的延长而显著提高,经历了从中间相小球到小球发生融并,最后形成了马赛克织构的中间相。纺丝性能测试表明,反应温度为410或420℃,反应4h制得的中间相沥青,可以熔融纺丝,经氧化和碳化后制得两组碳纤维。     

A structural study on the stabilization and enhancement of mesophase pitch fibre

The components of coal tar-derived mesophase pitch fibre and its blend with polyvinyl chloride (PVC) pitch were studied for chemical changes after the stabilization. Microanalyses, solubility and solid ¹³C NMR measurements were performed. The temperature was found to be very influential on the progress of the stabilization. At a temperature of 230° C, PVC pitch enchanced the oxygen uptake of both fusible pyridine soluble (PS) and non-fusible pyridine insoluble (PI) fractions in the pure mesophase pitch, so shortening the time required for complete stabilization and raising more rapidly the softening point of the PS fraction. More oxygen-containing functional groups, such as phenolic, ether, carboxylic and carbonyl groups, were formed in both fractions. It is noted that any increase in the aromatic ring size of the PI fraction is rather limited at this temperature. In contrast, stabilization of PVC pitch at a higher temperature of 300° C, accelerated the increase in PI without accelerating oxygen uptake of both fractions. Hence, the softening point of the remaining PS was unchanged or even lowered. An increase of aromatic ring size of the PI component by stabilization was marked at the higher temperature. Suggested stabilization schemes and the role of added PVC pitch in accelerating stabilization are discussed for each of these temperatures taking account of the above results.     

沥青球的HNO_3氧化和炭化行为(英文)

在室温条件下,以不同浓度的HNO3溶液(质量分数分别为10,20,30 and 40%)为氧化介质处理沥青球,而后直接进行高温炭化处理,利用FT-IR、XPS、SEM和元素分析表征HNO3氧化沥青球及其炭化样的化学结构和表面形貌。结果表明:用30%HNO3氧化12h的沥青球在900℃高温炭化后能够保持良好的球形度和表面形貌;HNO3处理引入的-NO2官能团在400℃前转化为胺基,促进了沥青分子的交联,保证了沥青球炭化过程的顺利进行;当炭化温度为900℃时,胺基进一步发生了环化和芳构化反应,氮原子以吡啶氮和季氮形式存在。     

Promoter action of sulphur on the stabilization of pitch spheres

Elemental sulphur was added into the starting pitch during the preparation of pitch-based spherical activated carbon in order to enhance the stabilization of pitch sphere. Pitch sphere (diameter 0.65–1.0 mm) without adding sulphur needs slow heating rate of 0.5 °C/min, high final temperature of 300 °C and long holding time of 20 h for the successful stabilization in air. While adding elemental sulphur with 2.5–10.0 wt % in total amount into starting pitch decreased the stabilization time significantly, pitch sphere containing 5.0 wt % of sulphur can be stabilized in air very easily at heating rate of 2.0 °C/min up to 270 °C without any holding time, and the successful stabilization time was only 3 h. Pitch molecules reacted with sulphur and some sulphur functional groups, such as C–SH, C–S–C, C=S, O=S=, O=S=O etc., were formed besides the oxygen functional groups under the stabilization condition. All of these sulphur functional groups acted as bridge bonds to make the pitch molecules polymerized so as to high up the softening point of pitch spheres, making the pitch spheres stabilized. Three kinds of sulfocompounds, i.e. H₂S, COS and CS₂ evolved in stabilization process.     

Structure and stabilization reactivity of mesophase pitch derived from f c c-decant oils

Structure and stabilization reactivities of three mesophase pitches (MP-1-3) derived from fluid catalytic cracking (f c c)-decant oils were compared to reveal the structure-reactivity correlation in the stabilization reaction, which is the slowest step of the pitch-based carbon fibre production. Analyses of the toluene soluble fraction in mesophase pitches using ¹H-, ¹³C-nuclear magnetic resonance (NMR), infrared and FD-mass spectroscopy suggested that the most abundant molecules in MP-2 and MP-3, which should have the highest and lowest softening points, respectively, consisted of a 7-ring aromatic skeleton with two phenyl groups, molecular weight 478 and a 10-ring aromatic skeleton with a phenyl and four methyl groups, molecular weight 556, respectively. MP-3 exhibited much more rapid stabilization and oxygen up take than MP-2. The analysis of stabilized fibre with Fourier transform-infrared spectroscopy indicated that the oxidative stabilization consisted of the following three steps: (1) oxygen up take to produce functional groups such as carbonyl, phenolic and ether groups; (2) growth of the aromatic ring; and (3) molecular association through hydrogen bonding. The first step of oxidation occurred at substituent alkyl, naphthenic and isolated aromatic hydrogens in the mesogen molecules regardless of the mesophase pitches. The reactivity of the mesophase pitch appears to be correlated to the number of such groups present.     

Analysis of coal tar pitch and smoke extract components and their cytotoxicity on human bronchial epithelial cells

Coal tar pitch and its smoke are considered hazardous by-products and common pollutant generated from coal industry processing. In this study, coal tar pitch and its smoke extracts were characterized by gas chromatography/mass spectrometry (GC/MS) with dimethylsulfoxide. We identified only 0.3025% of components in the total coal tar pitch using GC/MS. Among 18 identified compounds, polycyclic aromatic hydrocarbons (PAHs) has the highest relative abundance (0.19%). The remaining components were composed of monocyclic aromatic hydrocarbons, heterocyclic compounds and alkenes. In contrast, among 38 coal tar pitch smoke extract constituents that have been profiled, 87.91% were PAHs, and the remaining 12.09% were composed of monocyclic aromatic hydrocarbons, heterocyclic compounds and alkenes. The cytotoxic effect of coal tar pitch and its smoke extracts on BEAS-2B cells were also evaluated by MTT assay. BEAS-2B cells exposed to coal tar pitch showed a non dose-dependent U-shaped cytotoxicity with a dosage for maximal inhibitory of 3.75 mg/L. In contrast, BEAS-2B cells exposed to coal tar pitch smoke extracts showed a dose dependent cytotoxicity with a LC(50) of 8.64 mg/L. Our study demonstrated the significant different composition and cytotoxicity of coal tar pitch and its extracts, suggesting two different underlying mechanisms that are pending future investigation.     

添加剂对煤沥青在喹啉不溶物滤饼中渗透性的影响

本工作研究了添加剂对煤沥青的渗透性的影响.本研究采用的添加剂是阳离子型和非离子型添加剂的混合体系.它们对煤沥青的粘度和组成的影响很小,但是渗透性却有大幅度提高,根据达西定律和渗透系数方程对煤沥青浸渍动力学进行了讨论,认为添加剂起到了凝聚QI颗粒、增大有效尺寸和增大孔隙率的作用,改变了滤饼结构.随着其含量的增加,渗透性呈现先增加后减小的规律.通过对2D炭预制体致密化发现,添加剂能够提高煤沥青对高密度的预制体的致密化效率.