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

Abstract

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.

Dual responsive wool fabric by cellulose nanowhisker reinforced shape memory polyurethane

“…Above transition temperature ( T g or T m ), the mobility of soft segment increases, leading higher free volume and increase in pores for passage of more water vapor molecules and below transition temperature the low mobility of soft segment provide lower water vapor permeability and insulating effect . Produced SMPU polymers were investigated in the form of film for smart breathability, fiber to produce fabrics having smart breathability and bagging recovery as a result of dimensional change, coating/finishing applications for smart breathability, wrinkle recovery, crease retention and anti‐felting stimulated by temperature. Among these applications, coating and/or finishing methods have been widely used for their widespread application areas and economic advantages.…”

“…Among these applications, coating and/or finishing methods have been widely used for their widespread application areas and economic advantages. Therefore, SMPU was applied to cotton and poliester fabrics for smart breathability and active thermoregulation. Besides enhancing smart breathability and insulation, other smart mechanical functions such as pilling resistance, anti‐felting, crease retention, dimensional stability, pattern keeping, bagging recovery and strength improvement can be obtained by SMPU finishing applied to wool fabric .…”

Elasticity and Shape Memory Effect of Shape Memory Fabrics

“…DMDHEU, on the other hand, forms crosslinks between cellulose chains resulting in induced residual strain inside the fibers. This phenomenon reduces the elastic nature of the fiber and restricts the complete recovery of the molecular chains [19]. The X-ray photoelectron spectroscopy (XPS) measurements also demonstrate the possibility of polyurethane grafting onto the surface of cotton fabric finished by SMP chemicals, and the fourier transform infrared spectra (attenuated total reflection (ATR)) studies further illustrate the reactions of polyurethane with the hydroxyl groups of cotton resulting in grafted products.…”

Polymer-Based Smart Coatings for Comfort in Clothing

“…Nevertheless, the area of coating of SMP to textiles is relatively new and reported developments are scarce. One promising method is based on a highly adhesive resin coating solution by dissolving polyurethane SMP in dimethylacetamide [19] or graft ing to cotton [20][21] and wool [22] fabrics. Th e coating process is reported as being highly effi cient as already a small content of SMP is suffi cient to transfer the shape memory eff ect to the fabric.…”