碳化是聚丙烯腈纤维结构发生转化的重要过程.研究表明,低温碳化能使纤维中碳质量分数增加,氮和氧相对质量分数降低了1/3,大部分氧和氮被保留在结构中.纤维表面碳以中性碳为主,氮结构主要保留于环状结构中.增加低温碳化时间,能够使纤维中富集更多碳,表面上中性碳及萘啶或氢取代萘啶环上氮也增加,但增加幅度不明显.高温碳化能够脱除大部分的氧和氮,在相同高温碳化时间下获得的碳纤维碳质量分数差异较小,缩小低温碳化纤维的组成差异.延长高温碳化时间能够进一步提升纤维碳质量分数.%Carbonization is an important process of structure transformation of polyacrylonitrile-based carbon fi-bers. Carbon content was increased in pre-carbonization process, and the relative contents of nitrogen and oxygen were decreased by 1/3, which meant that the majority of the two elements were preserved in the fiber structure. On the surface of fiber, neutral carbon existed as the major formation of carbon, about nitrogen mainly existed in cy-clic structures. More carbon could be found in the fiber, and more neutral carbon and nitrogen in naphthyridine or hydronaphthyridine rings on the surface of fiber with increasing the pre-carbonization time. The carbon contents of the fiber obtained in the same carbonization process were almost same, whatever the time of pre-carbonization. Car-bonization reduced the difference of different pre-carbonized fibers. The majority in oxygen and nitrogenin the fibers were removed in carbonization, and carbon content was further increased with increasing the time of carbonization.
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