Study on the processing of thermoplastic polyvinyl alcohol with ammonium salts by melt spinning and its potential as a precursor fiber

Abstract

Polyvinyl alcohol (PVOH) has all the essential requirements to be used as an alternative precursor for carbon fiber (CF) production. Within this work, three different commercially available, thermoplastically processable PVOH grades together with three different ammonium salts as stabilizing agents were investigated using the melt spinning process with regard to their processing into CF precursor filaments. Precursor filaments could be spun at up to, 500 m min⁻¹. The distribution of the salts over the filament cross-section was evaluated using energy-dispersive X-ray spectroscopy analysis, whereas the quantitative determination was carried out using Kjeldahl nitrogen analysis. The thermal properties were characterized using thermogravimetric analysis. An increase in the ammonium iodine (NH₄I) concentration to 10.0 wt.% leads to 22.4 wt.% mass residue at 1000°C. The precursor filaments were carbonized in a laboratory tube furnace up to 1000°C and initial tests were carried out on the resulting CFs.