Preparation and properties of cationic waterborne polyurethane/acrylate for fluorine‐free water repellents

Abstract In this work, cationic waterborne polyurethane/acrylate (WPUA) was synthesized for water repellent in cotton fabrics to replace fluorine‐containing finishing agents with the concerns of ecosystems and human health. First, the tertiary amines monomers, N ‐methyl diethanolamine, 3‐dimethylamine‐1, 2‐propylene glycol, N , N ′‐bis (2‐hydroxyethyl)piperazine, were used as chain extenders to prepare waterborne polyurethane, respectively. Long‐chain octadecyl acrylate monomers were then grafted to the waterborne polyurethane by a self‐emulsifying method. The stable WPUA suspensions of positively charged latexes were obtained and could be finished on cotton fabrics via a simple pad‐curing process. The coated cotton fabrics were capable of repelling common liquids without any penetration, and the contact angles of the treated cotton fabrics could reach 150°. The WPUA latex films also exhibited good tensile mechanical properties and thermal dimensional stability. The cotton fabric coated with the WPUA showed good laundering durability, and its static water contact angle was still maintained at 142° even after 50 times washing. This work not only highlights the structural design and preparation but also provides a feasible strategy for fluorine‐free water repellency in cotton fabrics, which has great potential application prospects for a variety of fields.