Abstract
Inter- and intramolecular chemical reactions and their kinetics for 13C-labeled atactic-polyacrylonitrile (aPAN) powder heat-treated at 220–290 °C under air and vacuum were investigated by various solid-state nuclear magnetic resonance (ssNMR) techniques. By applying 13C direct polarization magic angle spinning (DPMAS) as well as through-bond and through-space double quantum/single quantum ssNMR techniques, it was concluded that aPAN heat-treated under air at 290 °C for 300 min adopted the ladder formation, namely, conjugated six-membered aromatic rings with partially cross-linked and oxidized rings and polyene components. In contrast, aPAN heat-treated under vacuum at the same condition thermally decomposed into oligomeric chains that were mainly composed of isolated aromatic rings connected by alkyl segments. Furthermore, early stages of the chemical reactions were investigated by 13C cross-polarization (CP) and DPMAS spectra. The latter provided quantitative information regarding the kinetics of the chemical reactions. As a result, it was shown that chemical reactions under oxygen occurred homogeneously with a higher activation energy (Ea) of 122 ± 3 kJ/mol compared to that of vacuum at 47 ± 2 kJ/mol. By comparing both chemical structures and kinetics under two different conditions, the chemical reaction mechanisms of aPAN will be discussed in detail.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
