Manmade protein fibers are produced by dissolving proteins like casein from milk, soya bean protein, and zein from corn in diluted alkali and forcing these solutions through a spinneret into an acid-formaldehyde coagulating bath.
Azlon is the generic name given to manufactured fibers composed of a regenerated natural protein. Azlon is produced by dissolving proteins like casein from milk, soya bean protein, and zein from corn in dilute alkali and forcing these solutions through a spinneret into an acid-formaldehyde coagulating bath. Many of the properties of these fibers resemble the natural protein fibers, but they suffer from low dry and wet strength and sensitivity to alkalies.
Protein-Polyacrylonitrile Graft Copolymer
A fiber consisting of a copolymer of casein protein (25%-60%) grafted with 40%-75% acrylic monomers, of which at least half is acrylonitrile, has been developed in Japan under the tradename Chinon.
The casein dissolved in aqueous zinc chloride and grafted with acrylonitrile is wet or dry spun into fibers. The fiber has a tenacity of 3.5-5 g/d (32-45 g/tex) dry and 3-4.5 g/d (27-40 g/tex) wet and an elongation at break of 15%-25% wet or dry. It recovers 70% from 5% elongation. The fiber has a moisture regain of 4.5%-5.5% and a specific gravity of 1.22. It dyes readily with acid dyes, but basic and reactive dyes can be used also. The fiber is marketed as a substitute for silk.