Acrylic precursor for carbon fibres and method for its preparation.

摘要

A method for preparing acrylic precursors with improved characteristics suitable for transformation into carbon fibres of superior mechanical characteristics comprises wet-spinning an acrylic polymer dissolved in dimethylacetamide followed by coagulation in a solvent-non solvent binary mixture bath of rigorously controlled composition and temperature, and a series of controlled-condition stretching operations with interposed washing stages, followed by yarn drying before its final collection. The method is characterised essentially by its coagulation stage, which is conducted under such rigorously controlled bath temperature and composition conditions as to obtain at the end of the process an acrylic yarn which has a perfectly compact structure practically free of flaws (voids), a perfectly circular cross-section and mechanical characteristics which are distinctly better than those of acrylic yarns of identical composition obtained by spinning processes of the known art. The specific destination of the acrylic yarn is the production of high-performance carbon fibres.