Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Influence of PAN-fiber stretching during thermal treatment on the stabilization reactions

: Meinl, Juliane; Kirsten, Martin; Cherif, Chokri; Michaelis, Alexander

Fulltext (PDF; )

American journal of analytical chemistry : AJAC 7 (2016), No.3, pp.282-293
ISSN: 2156-8251 (Print)
ISSN: 2156-8278 (Online)
Journal Article, Electronic Publication
Fraunhofer IKTS ()
PAN; polyacrylonitrile stabilization; cyclization; thermogravimetry; evolved gas analysis; molecular orientation

The stabilization of PAN-fibers without additional co-monomers was investigated with thermo-gravimetry and evolved gas analysis (FTIR-spectroscopy and MS-spectrometry). One fiber type had been drawn after spinning, while the other was used as-spun. During the thermal treatment, fiber shrinkage was either restricted or unrestricted. Investigations of influencing chemical and physical reactions regarding this restriction were conducted. Differences in the mass loss and gas emissions were observed, depending on the strained or unstrained state of the fibers. The change of crystallinity and molecular orientation of the fiber as reason of the measured variations was discussed. The emission of ammonia and other nitrogen containing gases (supposedly nitriles/ isocyanates) could be attributed to different aspects of the stabilization process. The length restriction resulted in a change in ammonia emission, associated with the cyclization reaction of poly acrylonitrile. The onset and amount of side reactions were influenced as well.