Chronological effects of oxygen on the structural transformations of polyacrylonitrile fibers during the rapid thermal stabilization process.

ABSTRACT: This study investigates the chronological effects of oxygen on the structural transformations of PAN fibers during the rapid thermal stabilization process. In the shorter-time period, PAN fibers undergo a few thermal-driven dehydrogenation reactions alone, while the initiation of both oxidative dehydrogenation and oxygen uptake reactions requires a longer stabilization time. Interestingly, both the amorphous regions and the lateral crystallite sizes increase simultaneously during these periods, resulting in greater exothermic enthalpy. In the longer time period, cyclization reactions begin, and the chain structures gradually become ladder-like and aromatized. In contrast to PAN fibers exposed to nitrogen, another type of cyclization reaction involving the nitrile groups occurs with negligi

SUBMITTER: Li S 

PROVIDER: S-EPMC11541326 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature