Preparation of Amide-Type Polyurethane Biomimetic Chain Extenders and Their Application in the Softening Finishing of Functional Textiles

Abstract To overcome the limitations of insufficient fiber adhesion and inadequate wash-fastness associated with traditional silicone softeners, a polyurethane biomimetic chain extender containing catechol group was designed and synthesized. This chain extender was incorporated into the backbone of a polyurethane-modified silicone softener to produce a resin-type silicone softener, which was then used to treat cotton fabrics. The study characterized the chemical structures of the biomimetic chain extender and the softener, evaluated the emulsion stability of the finishing agent, and tested the crease recovery angle, softness, wash-fastness, and surface morphology of the treated fabrics. The results indicate that the biomimetic chain extender significantly enhances the desired performance characteristics of the polyurethane-modified silicone softener: fabrics treated with biomimetic chain extender exhibited a crease recovery angle of 148.5°, a 28.4% increase compared to the sample without; the softness value was reduced from 201.4 mN to 135.4 mN; fabrics treated with the biomimetic chain extender maintained satisfactory softness even after 30 washes. These results indicate that the introduction of the catechol group enhances the softener's adsorption and film-forming properties on the fiber surface. Through strong interfacial bonding, it improves the wash-fastness of the silicone softener as well as the fabric’s softness and wrinkle resistance, providing new insights for the molecular design of long-lasting textile finishing agents.