中间相沥青制备有序结构炭前驱体的研究

PREPARATION OF THE ORDERED CARBON BLOCK PRESURSOR BY MESOPHASE PITCH

以低QI含量的煤沥青为原料,通过控制热聚合时间得到不同甲苯可溶物(TS)含量的热塑性沥青中间相预聚体,并以中间相预聚体为原料考察了热态成型对中间相有序生长的影响.结果表明,在室温～600℃,成型压力为3.12MPa,中间相预聚体中TS含量为10.7%～26.3%(质量分数)时,通过热态成型能够得到有序柱状初坯体.通过偏光显微镜观察,其中间相液晶分子沿垂直于模压压力方向排列成纤维状长程有序结构,经1100℃炭化后测得炭前驱体样品的电阻率纵向为1.78Ω.cm～2.99Ω.cm,横向为0.83Ω.cm～1.41Ω.cm.由此所得有序炭前驱体具有显著的择优取向结构,属于易石墨化碳,为制备高导热炭材料奠定良好基础.

High-thermal-conductivity carbon material is a focus of new carbon material research field. With few QIs coal tar pitch as raw material in this work, the thermoplastic elastomer mesophase pitch was prepared by the different thermal polymerization time. The mesophase pitchs containing various TI were moulded respectively at 25 ℃ to 600 ℃ under 3.12 MPa. The effect of hot press molding on the development of ordered mesophas.e was studied. The results showed that： when TS contents of mesophase pitch lay between 10.7% to 26.3%, the ordered columnar billet was successfully preparaed by hot press molding. It is shown by polarizing microscope that the regional mesophase displayed a sort structure of long fibrous, highly ordered and the mesophase liquid crystal molecules were aligned perpendicular to the compressing direction in the molding process. After carbonization at 1 100 ℃, the longitudinal and lateral resistivity range of the carbon block precursor was 1.78 12 Ω· m-2.99Ω·m, 0. 83 Ω· m-1.41 Ω·m, respectively. It exhibited a sort of preferred orientation and easy graphitization, so it was the ideal precursor for the high-thermal-conductivity carbon block.