A prerequisite for the effective transfer of the shape-memory effect to cotton fibers

Subtle interaction between shape-memory polymer and cellulose fibers within fabrics remains a critical issue for understanding their thermal-mechanical properties and thus the shape-memory behavior in cotton fibers. We demonstrate here the efficacy of Raman spectroscopy to probe the induced stresses in warp and weft fibers, presenting physicochemical features for cellulose fibers finished with macromolecule polyurethane and small-molecule dimethyloldihydroxyethyleneurea. Accordingly, a possible mechanism for transfer of the shape-memory effect to fabrics is proposed. Forming as a coating on the fiber surface after the finishing process, the shape-memory polymer takes a critical role in reducing the residual stress in weft fibers, establishing the prerequisite for reserving the shape-memory effect to fabric. In addition, this work has demonstrated that Raman spectroscopy is able to probe the residual stresses in cotton fabrics after being treated by chemicals in addition to that due to physical deformation. Our result provides clear evidence that in the finishing process strength reduction in fibers in general is not only caused solely by a chemical reaction, but also by a physical modification of the cotton structure.