煤沥青热聚合过程对微孔炭特性的影响

The Effect of Oxidative Polymerization of Pitch on Properties of Micro-pore Carbon

煤沥青是一种热塑性物质，作为制备高比表面积微孔炭的原料需要进行不熔化处理。煤沥青经氧化聚合后，挥发分由52．22％下降到16％以下，相应的甲苯不溶物含量由30％增加到81％以上。IR光谱分析发现：沥青氧化聚合的结果表现为3000～2900cm^-1附近甲基、亚甲基振动峰逐渐消失，1600cm^-1附近C=C芳环骨架振动峰、744cm^-1处渺位构型取代基峰同样显著减弱，通过脱亚甲基与渺位H实现芳环的稠和聚合，从而降低了稠和分子的芳香性。为此以中温煤沥青为原料制备高比表面积活性炭时需要选择适宜的加热氧化速度，以保持前驱体的反应活牲。制备高比表面积活性炭时，要求前驱体中的中间相保持适宜尺度，并高度呈分散状分布于各向同性沥青之中。以本试验制备的前驱体采用KOH活化与炭化时发现：其BET、孔径分布与沥青氧化聚合工艺条件有关，中孔主要集中于2～3m、微孔分布主要集中在1．4nm附近，基本不含5nm以上的孔。

Pitch is a kind of thermoplastic material. It needs to be treated into infusible material as raw material of prepared micro-pore carbon of high surface area. After oxidative polymerization of pith, its volatile matter is decreased from 52. 22% to 16%, and its toluene insoluble matter is increased from 30% to 81%. It is found by IR spectra that during oxidative polymerization of pitch, the peaks of methane and methane in 3.000-2900cm^-1 are derceased, the peaks of aromatic ring（C=C） in 1600cm^-1 and substitute in 744cm^-1 are also decreased. The aromaticity of condensed pitch molecule is decreased by oxidative polymerization. When using the pitch as a raw material to prepare micro-pore carbon of high specific surface area, the optimum rate of oxidative polymerization should be chosen to obtain the reactive activity of precursor. It is found that when preparing micro-pore carbon of high surface area, mesophase size in precursor is optimum and dispersed in pitch. It is found by carbonization and activation with KOH that the BET and pore distribution of micro-pore carbon are related to process condition of prepared precursor. Middle pore is mainly in 2-3nm, micro-pore is mainly in 1.4nm, and no pore is found more than 5rtm.