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Materials and Processes for Textile Warp Sizing
Published in Menachem Lewin, Stephen B. Sello, Handbook of Fiber Science and Technology: Volume I Chemical Processing of Fibers and Fabrics, 2018
Peter G. Drexler, Giuliana C. Tesoro
These fibers are copolymers of acrylonitrile (35–85%) with significant amounts of halogenated comonomers (e.g., vinyl chloride). Modacrylics have excellent resistance to sunlight, acids, alkalies, and biological attack. They are unaffected by most solvents, but dissolve in hot acetone. Modacrylic fibers are flame resistant and do not drip when exposed to elevated temperature. Modacrylics have good dimensional stability in hot water below the boil. Specific gravity is 1.28–1.38, depending on the comonomer. A summary of physical properties (20°C and 65% RH) shows:
Monomers, Polymers, and Plastics
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Acrylic fibers are a major synthetic fiber class developed about the same time as polyesters. Modacrylic fibers are copolymers containing between 35% and 85% acrylonitrile. Acrylic fibers contain at least 85% acrylonitrile. Orlon is an acrylic fiber developed by DuPont in 1949; Dynel is a modacrylic fiber developed by Union Carbide in 1951.
Medical textiles
Published in Textile Progress, 2020
Acrylic (polyacrylonitrile, PAN) was first developed and marketed under the trade name Orlon by Dupont in the 1940s [119]. PAN fibres do not consist solely of polyacrylonitrile, but are copolymers wherein over 85% of the monomer used consists of acrylonitrile and less than 15% is a vinyl monomer selected to improve processing and properties. For example, vinyl alcohol may be employed as the co-monomer to improve absorption. If the fibre contains more than 15% of a copolymer, it is described as a modacrylic [10]. The filaments are usually wet spun from aprotic solvents such as dimethyl sulfoxide into a coagulating bath, though when a higher resistance to abrasion is required, they can be dry spun. For commodity acrylic fibre products themselves, the material is used predominantly in fibre form, and tow-to-top conversion is carried out mainly by stretch-breaking of the filament tows, but it is fair to say that PAN fibres themselves have little profile at present in the medical textiles field; however, PAN filaments are the main precursor chosen for the preparation of carbon fibres which find use in braces and artificial limbs. The internal structure of the PAN filament used can significantly affect the properties of the resultant carbon fibre. For example, it has been shown that air-gap wet spinning can yield an improved PAN precursor with reduced numbers of voids and yield the preferred circular or close-to-circular cross section for the carbon fibre [120].