Preparation and properties of fibers containing mixed polymers. III. Polyacrylonitrile‐silk fibers

Fibers containing both polyacrylonitrile and silk have been spun using an aqueous solution of ZnCl 2 (56% ZnCl 2 by weight) as solvent. The relative polymer proportions ranged from 100% polyacrylonitrile to 20% polyacrylonitrile. The conditions under which the fibers were spun are discussed, as are the results of various measurements on the fibers. The x‐ray diffraction patterns, optical appearance, absorptive capacity for water and an acid dye, electrical resistivity, and mechanical properties of the fibers were studied. A few measurements on the compatibility of the polymers in solution are also reported. The results suggest that the fibers contain small, discrete regions of each polymer which are neither highly crystalline nor strongly oriented.