Acrylonitrile swollen thread for carbon fiber, precursor fiber bundle, fire resistant fiber bundle, carbon fiber bundle and production methods thereof

摘要

A swollen acrylonitrile fiber for a carbon fiber having openings 10 nm or more in width in the circumferential direction of the swollen fiber with a ratio in the range of 0.3 openings / μm2 or more and 2 openings / μm2 or less on the surface of the swollen fiber, and that is not treated with a finishing oil agent.