Temperature dependence of processes during oxidation of PAN fibres

✍ Scribed by V. Rašković; S. Marinković

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 430 KB
• Volume: 13
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(75)90057-3

✦ Synopsis

The 3000-PAN-filament tows have been stretched by a constant axial load during heating in air at a constant rate of 7,5"C/min. The extension of the tow begins about the glass-transition temperature (70°C). Temperature dependence of the fibre diameter, width of X-ray reflection of the PAN, and endothermic effect occurring at low temperature (below 24O"C), suggest that at 130°C begins a molecular rearrangement. IR spectra of the oxidized fibres and gas evolution suggest that near this temperature (at about 145°C) begins cyclization, but the cyclized fraction of the fibres remains very low up to over 22O"C, unless a prolonged oxidation at this temperature is carried out. TGA and DTA results suggest that at about 240°C begins rapid cyclization, which is at about 320°C followed by partial degradation of the fibres. In these processes the fibres lose about 26% of their original weight. Final degradation of the fibres begins at about 4OO"C.-