Cotton fibers, polymerization

Work began in the 1930s on the development of flame-retardant cottons based on chemical systems that either reacted directly with the ceUulosic substrate, or polymerized on or in the cotton fiber. A serious effort in this direction, mounted from the 1950s through the 1970s, resulted in most of the state-of-the-art flame-retardant finishes for cotton available. 

Fig. 5. Magnified cross section of cotton fibers after intrafiber polymerization of methactylate. a. Fiber crosslinked in unswollen state to give increased resiliency v en dry. b. Fiber not crosslinked. (Distance between marks is 1 p) (44)...

Materials. Scoured cotton cellulose fibers of the Acala variety supllied by Kanebo Co Ltd. were piirified by extracting with hot benzene-ethanol mixture (l l vol. ratio) for 2kh. Then the cotton fibers were washed with methanol and distilled water and air-dried. Acrylamide (AM) was purified by recrystallization from benzene for several times. Bis-(beta-chloroethyl) vinylphosphonate (Fy) was purified by passing the monomer through a column filled up with activated alumina to remove inhibitors of polymerization. Other chemicals used were reagent grade, and were used without further purification. 

An alternative to solvent-phase synthesis of CEPs is vapor-phase polymerization (VPP). This route was first used for PAn s in 1998 for the deposition of conducting PAn films on cotton fibers, by impregnating the thread with (NH SjOg oxidant and then exposing the surface to aniline vapor.94 Polyacrylamide films coated with conducting PAn (conductivity ca. 10-5 S cm-1) have been similarly prepared.95... 

Hessler, L.E., Merola, G.V. and Berkley, E.E. (1948) Degree of polymerization of cellulose in cotton fibers. Textile Research Journal, 18, 628-634. 

For most textile uses, a DS <1 is desirable. Cyanoethylation can impart a wide variety of properties to the cotton fabric, such as rot resistance, heat and acid resistance, and receptivity to acid and acetate dyes. Acrylonitrile and acrylonitrile polymers (qv) has also been radiation-pol5unerized onto cotton with a °Co source. Microscopical examination of ultrathin sections of the product shows that the location of the polymer is within the fiber (120). Examination of the ir spectrum of cotton-containing polymerized acrylonitrile indicates that grafliing occurs at the hydroxyl site of the cellulose (121). Another monomer grafted onto cellulose by irradiation is styrene polymers (qv). Chemical properties, mechanisms, and textile properties of these grafted poisoners of cellulose have been summarized... 

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