Controlling Shrinkage in Wool Fabrics: Effective Hydrogen Peroxide Systems

摘要

Alkaline hydrogen peroxide (H_2O_2) systems, including dicyandiamide, gluconic acid, and Triton X surfactant, used alone or followed by enzyme treatments, are investigated for their effectiveness in imparting shrinkage resistance to wool fabrics. Fractional factorial analysis shows that H_2O_2 is the most important factor and enzyme the second contributing factor in shrinkage control. An effective H_2O_2, nonenzymatic system with Triton X-114 limits structural changes to surface smoothing of the fibers and yields a relative area shrinkage of 2.95%. Another effective H_2O_2 system, using the same pretreatment but followed by an enzymatic treatment with additives―polyacrylamide to restrict enzyme activity to the fiber surface and sodium sulfite to reduce disulfide linkages―yields 1.16% area shrinkage. The most important factor in shrinkage control is replacing the hydro-phobicity of the wool's surface with an anionic charge through the formation of cysteic acid. This leads to the release of 18-methyleicosanoic (18-MEA) acid from the fiber surface and underlying cell membrane complex attached to the surface scales of wool through thioester linkages. TLC, FTIR, and EI-MS are used to prove the presence of fatty acids and 18-MEA in spent baths and in extracts of the treated fabrics. Imparting hydrophilicity to wool by conferring an anionic charge suggests new possibilities for wool reactivity.