煤沥青中β树脂热转化产物的微观结构

Microstructure of thermal conversion products of β resin from coal tar pitches

  • 摘要: 分别以甲苯和喹啉为萃取剂对3种典型沥青(中温沥青、热缩聚改性沥青和氧化改性沥青)进行二级溶剂萃取-热过滤-蒸馏处理,得到3种β树脂(依次命名为β-1,β-2和β-3)。利用元素分析仪、TGA和FTIR结合分峰拟合的方法对3种β树脂的基础物性进行了研究。对3种β树脂进行热转化和炭化处理制备得到3种β树脂基沥青炭(分别命名为β-1-C500-P,β-2-C500-P和β-3-C500-P)。利用偏光显微镜(PM),XRD和Raman光谱结合分峰拟合的方法对3种热转化产物的微观结构进行了定量研究。结果表明:β-1-C500-P的偏光显微结构中细纤维结构含量为24.71%,小片结构含量为56.32%; β-2-C500-P的偏光显微结构中细纤维结构含量高达40.40%; 而β-3-C500-P的偏光显微结构则主要是各向同性结构和少量的镶嵌结构。β-1-C500-P和β-2-C500-P中趋于规整炭微晶含量Ig分别为78.78%和82.43%,微晶尺寸Lc分别为1.90 nm和1.94 nm,然而β-3-C500-P的Ig和Lc则明显小于二者,分别为53.17%和1.58 nm。β-1-C500-P,β-2-C500-P和β-3-C500-P中理想石墨微晶含量(IG/IAll)依次为10.13%,10.46%和8.51%,无定形碳含量(ID3/IAll)分别为10.94%,10.48%和11.55%。3种β树脂热转化产物的偏光显微结构定量分析结果与炭微晶分布结果(XRD和Raman结合分峰拟合定量分析)相吻合。

     

    Abstract: Three kinds of β resin (named as β-1, β-2, and β-3) were obtained with the method of secondary solvent extraction, hot filtering and distillation.In this process, the toluene and quinoline were used as the solvents, three typical types of pitches (medium pitch, thermal modified pitch, and oxidation modified pitch) were used as the raw materials.Elemental analyzer, TGA, and FTIR spectrum combined with curve-fitting method were used to study the basic physic properties of β resins.Three kinds of β resins based carbon (named as β-1-C500-P, β-2-C500-P, and β-3-C500-P, respectively) were obtained using the methods of thermal conversion and carbonization process.Polarizing microscope, XRD and Raman spectrum combined with curve-fitting method were used to characterize the microstructure of the thermal conversion products.The results show that the fine fibrous structure and leaflet structure of β-1-C500-P were 24.71% and 56.32%, respectively.The fine fibrous structure of β-2-C500-P was 40.40%.However, the polarized microstructures of β-3-C500-P were mainly composed of isotropic texture and mosaic texture.The contents of ordered carbon crystallite (Ig) of β-1-C500-P and β-2-C500-P were 78.78% and 82.43%, respectively.The crystallite sizes (Lc) of these two kinds carbon were 1.90 nm and 1.94 nm.However, the Ig and Lc of β-3-C500-P were 53.17% and 1.58 nm respectively.The contents of ideal graphite microcrystalline (IG/IAll) of β-1-C500-P, β-2-C500-P, and β-3-C500-P were 10.13%, 10.46%, and 8.51% respectively.The contents of amorphous carbon (ID3/IAll) were 10.94%, 10.48, and 11.55% in turn.The result of polarization microstructure is well correlated with the distribution of carbon crystallite (the results from XRD and Raman spectrum combined of curve-fitting method).

     

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