中间相炭微球的二次生长

The secondary growth of mesocarbon microbeads

为考察中间相的形成和生长机理,将一种煤沥青制备的中间相炭微球添加到另一种沥青中进行二次热缩聚,结果发现中间相炭微球可以进行二次生长。二次热缩聚中间相炭微球的产率、粒径分布、表面和断面的形貌表明添加的中间相炭微球对于沥青热缩聚过程的物理作用更为主要;二次热缩聚过程包含了添加的中间相炭微球的二次生长过程和原料沥青独立成核生长两个相互竞争的过程,中间相炭微球的添加量对这两个过程有着重要的影响;中间相炭微球的生长是基本构筑单元不断进入相界面的构筑过程。

A small quantity of mesocarbon microbeads （MCMBs） derived from a coal tar pitch were added to another coal tar pitch to investigate the formation and growth mechanism of MCMBs. It was found that new MC- MBs were also observed. A further analysis of particle size distributions, morphology and cross-section texture of the new and added MCMBs as well as their total yields showed that the secondary growth of the added MCMBs was mainly driven by physical interactions. The thermal condensation of the pitch included nucleation of raw pitch to form the new MCMBs and secondary growth of the added MCMBs. The two parallel processes competed with each other and the dominating one was determined by the fraction of the added MCMBs. It was concluded that the basic structural units of MCMBs moved from the parent pitch onto the surface of MCMBs during the growth.