Alkali resistance of a casein‐acrylonitrile graft copolymer fiber

Abstract

The casein-acrylonitrile graft copolymer fiber was treated in sodium hydroxide, sodium carbonate, and sodium bicarbonate solutions to evaluate its alkali resistance which was very important for wet processing. The weight loss and whiteness of the treated fibers were examined. UV spectra of the alkaline treatment solutions and IR spectra of the treated fibers were analyzed. The study showed that the fiber exhibited poor alkali resistance. Treating temperature, alkali concentration, and strength affected the weight loss and whiteness of the treated fibers. A high weight loss was found even at low alkali concentration, and the obvious yellowing was observed at higher alkali concentration and temperature. The weight loss was primarily due to the hydrolysis of casein, whereas the yellowing was caused by the hydrolysis of nitrile groups and induced formation of C¼ ¼N conjugated system.

Bleaching of modal/AN‐g‐casein fiber blend with H2O2/TAED activating system

“…At present, most factories adopt alkaline H 2 O 2 bleaching. However, AN‐ g ‐casein fiber has poor alkali resistance as observed in the earlier study 5. The major casein component in AN‐ g ‐casein fiber is amorphous, and part of casein is not grafted with polyacrylonitrile 1–4.…”

“…Casein‐acrylonitrile graft copolymer fiber (AN‐ g ‐Casein fiber), one of successfully developed chemical fibers containing proteins, enjoys extensive academic researches 1–5. Modal fiber, one of new regenerated cellulose fibers, is processed by the dissolved beech pulp and has been widely used in textile industry because of its superior wettability, high strength, and good dyeability 6.…”

“…These inherent structures readily give rise to the loss of casein during the wet processing under alkaline conditions. Besides, the nitrile groups in polyacrylonitrile can be hydrolyzed to form imine (CN) conjugated system in the presence of high alkali (Scheme ),5, 7, 8 which produces a yellowing effect on this fiber. To avoid the issues of casein loss and fabric yellowing in alkaline medium, the proper bleaching approaches used for AN‐ g ‐casein fiber and its blend under nearly neutral conditions are necessary to be exploited and researched.…”

RSM optimized soy protein fibre as a sorbent material for treatment of water contaminated with petroleum products

“…Graft copolymerization is one of the promising techniques to improve the physical and chemical properties of biopolymers. Various workers have carried out graft copolymerization of vinyl monomers onto proteins using chemical and radiation techniques to incorporate desired properties [23][24][25][26].…”

Fabrication and Characterization of Highly Oriented Composite Nanofibers with Excellent Mechanical Strength and Thermal Stability

“…However, after the alkali treatment, the elongation at break of the PMIA/PAN-MWCNT fiber membranes was only 16%, which was less than 50% of the initial. It could be explained that the alkali resistance of PAN was not well, [46] and the structure of PAN in the composite fibers was destroyed under the action of alkali, leading to the decrease of the mechanical properties of composite membrane. Meaningfully, after high temperature, acid, and alkali treatment, the macroscopic morphology and microscopic morphology of the PMIA/PAN-MWCNT nanofiber membranes had hardly changed (Figure 7c,d), thanks to the stable molecular structure of PMIA and its supporting role in the composite fibers.…”