Atactic-polyacrylonitrile (a-PAN) is used as major precursor to produce carbon fiber. From a-PAN to Carbon fibers, several heat treatment processes including stabilization, carbonization and graphitization are involved. During stabilization, linear polymer structure is believed to convert to ladder structure, which makes it able to survive during further heat treatment at even higher temperature. For the past decades, several experimental approaches including FT-IR, DTA, TGA, etc., have been applied to characterize chemical structures of stabilized PAN. However, due to experimental limitations, stabilization process was still not well understood at the molecular level. In this talk, we report a solid-state NMR strategy to characterize a-PAN stabilized as a function of stabilization temperature and stabilization time by two dimensional 13C-13C and 1H-13C correlation NMR techniques.1,2 Through-bond correlation of stabilized a-PAN was successfully obtained to identify different chemical structures with the change of stabilization temperature. Improved spectral resolutions of 1 and 2D NMR data for the first time will reveal different stabilization pathways for PAN stabilized under air and nitrogen. Meanwhile, degree of stabilization can also be calculated through quantified 1D NMR spectra, which was also plotted as a function of stabilization temperature and time, respectively.

Elucidation of stabilization pathways of atactic-polyacrylonitrile by solid-state NMR spectroscopy

255th National Meeting (2018)

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