中间相炭微球乳化-聚合法制备及电化学性能

以石油基各向同性沥青为原料,采用乳化-聚合法制备出一种球形规整、粒径分布较窄的中间相沥青基微球（MPMB-et）。经过预氧化、炭化得到中间相炭微球熟球（MCMB-et）,采用扫描电镜（SEM）、高分辨透射电镜（HRTEM）、X射线衍射（XRD）和Raman光谱等分析手段表征了MCMB-et的外部形貌和微观结构,并对微球的储锂性能进行测试,结果表明：MCMB-et具有较大的比表面积（13.35m²/g）、较宽的层间距（0.352nm）和一定的结构无序度（内部类石墨片层堆积结构排列无序）,加快了锂离子在类石墨片层间及活性位点的嵌入和脱出。与直接热缩聚法（MCMB-t）和直接乳化法（MCMB-e）制备的微球相比,MCMB-et在循环性能和倍率性能方面均具有明显的优势,MCMB-et在500mA/g的电流密度下循环100圈仍能保持325.3mAh/g的比容量,并在2A/g的高电流密度下仍能保持240.0mAh/g的比容量。     

喹啉不溶物类型中间相炭微球结构性能的影响

以中温沥青、针状焦副产中温沥青和精制沥青为原料,热缩聚法制备中间相炭微球(MCMB)。通过对比喹啉不溶物(QI)和中间相的显微结构,研究QI类型对MCMB形成过程的影响。结果表明不同的沥青由于QI类型不同,中间相的形成过程存在差异,并影响MCMB的粒径、收率和性能。     

溶胶-凝胶法介孔沥青炭微球的制备及电化学性能研究

以水性中间相沥青(AMP)为前驱体,阳离子表面活性剂(CTAB)为结构导向剂,通过控制AMP的凝胶化和自组装过程,采用溶胶-凝胶法来制备介孔沥青炭微球。利用SEM、HRTEM、SAXRD、FT-IR等分析手段,对产物的形貌及结构进行表征,并研究了介孔沥青炭微球的形成机理和电化学性能。结果表明:在制备介孔沥青炭微球的过程中,CTAB与离子化的AMP可通过S+I-静电力作用形成凝胶球,经炭化后得到介孔沥青炭微球。当CTAB/AMP=1.2时(CTAB为2 g),炭化后得到的介孔炭微球之间界面明显,表面光滑,球体粒径为300~500 nm,当增加CTAB胶束在溶液中的浓度时,炭化产物中得到纳米炭棒。所得介孔沥青炭微球C-AMP1.2-800有序度差、石墨化度低,球体为乱层石墨结构,其在50 mV.s-1下的比电容为103.5 F/g。     

煤焦油系中间相炭微球的制备

以煤沥青为原料,采用热缩聚法制备中间相炭微球。用扫描电子显微镜（SEM）分析了煤沥青中原生喹淋不溶物（QI）的形貌,考察了不同有机溶剂对分离中间相微球的影响;并使用X－射线衍射方法（XRD）分析了炭化和石墨化炭微球的结构变化。     

成核剂对中间相炭微球性能的影响

以煤液化沥青为原料,炭黑、石油焦、石墨和针状焦为成核剂,在410℃恒温5h条件下,采用热聚合法制备中间相炭微球,并研究四种成核剂在相同热处理条件下得到的中间相炭微球,作为锂离子电池负极材料的性能.结果表明:以炭黑和石墨为成核剂可以制备得到粒度分布均匀、表面形貌较好的中间相炭微球.由电性能测试结果可知,首次可逆容量和首次效率分别为353.9mAh/g与92.9%和346.5mAh/g与92.6%.对比商品化中间相炭微球指标,发现以炭黑和石墨为成核剂制备得到的中间相炭微球,其性能与国内同类产品的性能相近.     

添加对甲苯磺酸对中间相炭微球制备的影响

以中温煤沥青为原料,在对甲苯磺酸(PTSA)不同添加量下,420℃恒温2h热缩聚制备中间相炭微球.利用元素分析、激光粒径分析、扫描电镜分析等手段对所得产物进行表征,研究了对甲苯磺酸添加量对中间相炭微球制备的影响.结果表明:在煤沥青中添加PTSA可以提高中间相炭微球的收率和C/H;中间相炭微球的平均粒径随PTSA添加量的增加呈先减小后增大的趋势;添加量约1%时,所得中间相炭微球粒径小,尺寸分布窄,球形度好.     

热缩聚工艺条件对中间相碳微球形成的影响

以中温煤沥青为原料采用常压热缩聚工艺制备中间相炭微球。考究了不同聚合条件对中间相碳微球收率及形态的影响，从而找出制备中间相碳微的最佳工艺中每。     

中间相碳/Co复合微球的制备

以煤沥青和乙酸钴为原料进行热缩聚反应，以吡啶为溶剂，分离制备出大小为20μm左右的中间相碳／Co复合微球，并研究了钴含量和热处理温度对复合微球结构的影响。研究结果表明，随着原料中乙酸钴含量的增加，制备出的复合微球钴含量增加。复合微球的X衍射图显示出明显的石墨碳和金属钴的衍射峰，2500℃石墨化后，复合微球中的钴仍能稳定存在。热处理过程中复合微球中钴对碳的石墨化有催化作用，钴含量越大，这种催化石墨化作用越明显。复合微球的TEM照片显示微球中钴颗粒大小为10～40nm，颗粒均匀分布在中间相碳基质中。     

热缩聚工艺条件对中间相炭微球形成的影响

以中温煤沥青为原料采用常压热缩聚工艺制备中间相炭微球。考察了不同聚合条件对中间相炭微球收率及形态的影响,从而找出制备中间相炭微球的最佳工艺路线。     

单分散羧基化PS微球的制备及自组装

通过无皂乳液聚合法制备羧基化的聚苯乙烯(PS)微球,并讨论了甲基丙烯酸(MAA)用量、引发剂过硫酸铵(APS)用量对单体转化率、微球粒径及其分布的影响。分别使用漂浮自组装法、单基片垂直沉积法和双基片垂直沉积法对聚合物微球进行自组装。结果表明:当MAA的摩尔分数为2%~8%,APS用量为0.168~0.504 g时,可制备单分散性良好的聚合物微球,且随着MAA,APS用量的增加,单体转化率增大,聚合物微球的粒径减小。与漂浮自组装法和单基片垂直沉积法相比,使用双基片垂直沉积法,当乳液固体质量分数为1.0%,微球自组装效果好,排列规整有序。     

Carbon foams with high compressive strength derived from mixtures of mesocarbon microbeads and mesophase pitch

Carbon foam with relatively high compressive strength and suitable thermal conductivity was prepared from mixtures of mesocarbon microbeads (MCMBs) and mesophase pitch, followed by foaming, carbonization and graphitization. The influence of addition amount of MCMB on the properties of as-prepared carbon foams was investigated in detail. Results showed that addition of MCMBs into mesophase pitch could significantly reduce the amount and length of cracks in carbon foams, which results in increase of compressive strength of carbon foams. Carbon foam with high compressive strength of 23.7 MPa and suitable thermal conductivity of 43.7 W/mK, was obtained by adding 50% MCMBs into mesophase pitch, followed by foaming, carbonization and graphitization.     

酚醛树脂改性煤焦油沥青中制得的中间相球体的结构特征

Mesocarbon microbeads （MCMB） were prepared from coal tar pitch modified by phenolic resin and from the same pitch modified by phenolic resin and hexamethylenetetramine at 440℃ for lh. By investigating the morphology of mesophase spheres and the structure of the MCMB carbonized at 1000℃ for lh using scanning electron microscope （SEM） and XRD, it was found that phenolic resin accelerated the formation and coalescence of mesophase spheres. Some of the obtained MCMB were hi- or tri-spheres with the distorted microtextural carbon layers. Hexamethylenetetramine in the pitch modified by phenolic resin accelerated the condensation of phenolic resin and consequently expedited the combination of mesophase spheres, which was proved by the formation of some tetra-spheres. Owing to the cross-linkage of the additives, MCMB with complex structure were obtained.     

Effects of pitch fluoride on the thermal conductivity of carbon foam derived from mesophase pitch

Carbon foams with high thermal conductivity were obtained from mixtures of mesophase pitch and pitch fluoride. The addition of pitch fluoride in mesophase pitch could significantly increase the specific thermal conductivity of as-prepared carbon foams. After graphitization at 2873 K, the specific thermal conductivity of carbon foams increased from 82 up to 155.4 (W/mK)/(g/cm³) when the content of pitch fluoride was 3% in the raw material.     

Formation mechanism of carbon foams derived from mesophase pitch

Carbon foams were prepared from mesophase pitch using foaming, carbonization and graphitization processes. The physical and chemical properties of the mesophase pitch during thermal treatment were studied by Fourier transform infrared spectroscopy, thermogravimetry, mass spectroscopy, rheometry and scanning electron microscopy. The results suggest that gases released from the pitch dissolve, saturate, nucleate and grow in the molten pitch during foaming. Then the resultant bubbles coalesced with the neighboring bubbles driven by the surface tension of the molten pitch. This coalescence generates a shear stress to force aromatic planes of the pitch to arrange regularly and paralleled to the axis of a ligament. The growth of bubbles stopped when the pitch became semi-coke at a temperature above 733 K. The viscosity and surface tension of the molten pitch are major factors that influence the growth of bubbles. After carbonization at 1073 K and graphitization at 2873 K, the well aligned aromatic planes in the foams evolve into highly aligned graphitic structures.     

A two-stage preparation of mesophase pitch from the vacuum residue of FCC decant oil

The preparation of mesophase pitch as a precursor for the high-performance carbon fiber from a vacuum residue of FCC-decant oil (FCC-DOVR) was studied, applying a two-stage heat treatment to improve the pitch yield as well as its liquid crystal properties. The present two-stage preparation consisted of the pressurized heat treatment (1–5 MP) of the first stage at 430–480°C and the successive heat treatment under 13–260 Pa at 430°C. Such a two-stage preparation increased the yield of the spinnable mesophase pitch of 100% domain texture with lower softening point to 45% from 22% by the single-stage one from the same feedstock. Spinning properties of the mesophase pitch were excellent to allow smooth spinning for longer than 15 min and random orientation of mesogen molecules in the tranverse section of the fiber perpendicular to the fiber axis. The chemistry of the two-stage preparation for the higher yield and better properties as the fiber precursor is briefly discussed.     

炭前驱体形态对C/C复合材料导热系数的影响

利用热塑性中间相沥青为黏结剂,短炭纤维.增强体,一步热压成型制备C/C导热复合材料.采用SEM和偏光显微镜观察等分析手段,研究了2∶1,2.5∶1和3∶1三种不同管径比对C/C复合材料的影响.结果表明:通过热压模具空腔结构的改变可以引起炭前驱体挤出形态的变化,使得轴向基体炭有序生长与短炭纤维增强体呈现有序排列,其中间相液晶分子垂直和平行于模压压力方向均排列成纤维状长程有序结构,短切纤维呈现出与压力平行方向排布.当空腔管径比为3:1,轴向导热系数由86.2 W/(m·K)增大至115.5 W/(m· K),各向异性比由1.6减小为1.2.由此所得块体C/C复合材料具有显著的二维取向结构,轴径向导热系数趋于平衡.     

中低温煤焦油基炭微球的制备

通过馏分切割、温和加氢相结合对中低温煤焦油进行精制处理，精制后的原料采用分级热聚制备中间相炭微球。考察了精制处理条件对原料性质、中间相炭微球宏观外貌及微晶结构的影响。采用FTIR、GC-MS、族组成、元素分析对原料进行表征，采用SEM、XRD对中间相炭微球进行表征。结果表明：中低温煤焦油中300～430℃馏分油是制备中间相炭微球的较佳馏分。300～430℃馏分油中正庚烷可溶物（HS）质量分数高达84.76%，吡啶不溶物（PI）质量分数低至0.23%，杂原子含量低，芳烃化合物的环数为2～4环。300～430℃馏分油在T_H=350℃、p=8MPa、t=1.5h、剂油比1∶40（质量比）的条件下温和加氢得到的精制原料，经420℃热聚6h得制备的中间相炭微球宏观外貌、微晶结构较好。中低温煤焦油基炭微球的粒径范围为5～15μm，小球表面光滑，微观结构为地球仪型，经1450℃高温煅烧后，石墨化度达到12.33%。     

改性煤沥青中间相的微观结构研究

以对甲基苯甲醛(4-MB)为改性剂,在对甲苯磺酸(PTS)的催化作用下对煤沥青(CTP)进行改性制取沥青中间相。采用偏光显微镜研究改性煤沥青的光学组织结构;采用扫描电镜(SEM)观察改性煤沥青的形貌。结果表明:随对甲基苯甲醛的用量、温度及热处理时间的不同,改性煤沥青可得到超镶嵌(SM)、小域(SD)和广域(D)3种光学组织结构;在一定的工艺条件下,改性煤沥青的光学组织结构显著改善,出现了大量的中间相小球体;改性后煤沥青出现较好的纤维状结构。因此,改性后的煤沥青有望成为优质的沥青中间相。     

中间相和各向同性沥青基炭纤维的活化及其结果比较

研究了分别由中间相沥青和各向同性沥青为原料制备的两种活化纤维的结构与性能特征。通过低温N2气吸附等温线测定、扫描电镜（SEM）观察和X－射线衍射分析等方法,从微观结构上比较了两种沥青作为ACF制备原料的差异性。