Influence of liquid ammonia on the structure of wool fiber

Abstract

Liquid ammonia treatment of worsted fabric was carried out by a continuous liquid ammonia finishing machine, and the effects of liquid ammonia on wool surface morphology, chemical structure and crystallinity were studied and corresponding mechanism was discussed in detail. The results showed that liquid ammonia made the surface scales of wool remove partially and decreased the content of hydrophobic lipid layer and hydrophobic property. After liquid ammonia treatment, the secondary structure of wool macromolecule was changed, manifested in increased α-helix and decreased β-sheet; the disulfide bonds were broken to form cysteine sulfonate, cysteic acid and cystine oxides. Liquid ammonia increased the content of α-crystallization, causing an increase in the crystallinity of wool. As our knowledge goes, this is the most systematic report to date on the effect of liquid ammonia on the structure of wool fiber, and provides a novel medium for the modification of wool in a large scale. Furthermore, it also provides a theoretical basis for the commercial application of liquid ammonia as a non-aqueous medium in wool textile industry.