STUDIES ON THE FINE STRUCTURE OF ACRYLIC FIBER: THERMAL SHRINKAGE BEHAVIOR OF ACRYLIC FIBER IN AQUEOUS 80% DIMETHYLFORMAMIDE SOLUTION

Abstract

Temperature-shrinkage curve of acrylic fiber was mearured in aqueous 80% (v/v) dimethylformamide solution and the effects of polymer composition, stretching and thermal treatment were investigated as follows:
1) The temperature at which the maximum shrinkage is observed decreases with increasing in comonomer content.
2) The percent of the maximum shrinkage increases with increasing in stretching ratio and it gives a practical measure for fiber orientation.
3) The shape of temperature-shrinkage curve is affected by heat treatment. By relating to the studies of iodine adsorption and X-ray diffraction, it is concluded that the shape of the curve reflects lateral order distribution of acrylic fiber.
4) The structural feature of acrylic fiber was also discussed in terms of the concept that polyacrylonitrile is laterally ordered as a single phase combining the properties of both crystalline and amorphous.