No abstract

A series of reactive branched polyurethane dispersants (BPUs) were successfully synthesized based on epoxy as reactive group and nitrogen-containing heterocycles as anchoring group. The branched polyurethane was adopted an ''A 2 + B 3 '' approach with diisocyanate prepolymer and trimethylolpropane. The structure, molecular weight, and thermodynamic property of BPUs were characterized. The pigment dispersions were prepared with BPUs as the dispersant by ball milling, and then the characteristic parameters such as pigment particle size, viscosity, stability, color properties, and fastness were evaluated.Excellent dispersing performances were observed that the particle size of five dispersions were below 200 nm, with the viscosity as low as 6-9 mPaÁs. It is worth noting that the pigment dispersion prepared by BPU exhibited excellent stability and self-adhesive performance. These dispersions were printed on cotton fabrics without adhesives, their water washing fastness was approximately grade 4. And the dry rubbing and wet rubbing fastnesses were 3 and 2-3, respectively.

The development of vegetable oil‐based polymers was particularly suitable for the era of increasingly scarce petroleum. Self‐colored castor oil‐based waterborne polyurethanes (PUs) were successfully synthesized based on castor oil and 1‐amino‐4‐hydroxy‐2‐(6‐hydroxyhexyl) anthraquinone (DR) as polyols. The UV–Vis spectrum showed that the addition of carboxylic acid groups make the spectrum of the PU produce the hyperchromic effect under alkaline conditions. Castor oil‐based waterborne colored PUs possessed excellent stability under weak alkaline conditions. The connection of castor oil caused the PU to constitute soft polymer networks. PU coatings on cotton fabrics possessed excellent color properties. The urethane groups in the PUs formed hydrogen bonds with the hydroxyl groups on the cotton fibers and the polymer network structure formed by the PU coating itself made the color fastness of the cotton coatings reached grade 5. With the increase of castor oil content, the degradation rate of castor oil‐based waterborne colored PU increased from 3.45% to 3.65%. This work provides a way to impart excellent color properties and fastness to PU coatings by inserting dye molecules and vegetable oils into the PU macromolecular chain.

A responsive function is significant to surfaces with special wettability, especially for breaking through their limitations in practical applications. We report a novel strategy, which is effective, scalable, versatile, and low-cost, to produce the pH-responsive superwettable surface by combining the pH-responsive branched polymer nanoparticles (PRBNs) and conventional textile materials. The PRBN exhibiting a spherical shape with strawberry-like rough surface is able to swell (diameter of 71 nm) in an acidic aqueous solution and shrink to its original size (diameter of 42 nm) in a neutral or basic aqueous solution; moreover, the swelling–shrinking transition is reversible. The deposition of PRBNs on polyester fabric provides the surface pH-responsive wettability that is superhydrophobic to a neutral or basic aqueous solution (pH ≥ 7) with a contact angle above 150° and superhydrophilic to an acidic aqueous solution (pH 1) with a contact angle of 0°. Similar to the pH-responsive behavior of nanoparticles, this superhydrophobic–supehydrophilic transition of fabric is also reversible. By adjusting the hydrophobic substituents of PRBN, the wettability of fabric has remarkable changes. The adhesion of PRBNs onto polyester fabric can be obviously enhanced by the heating-press procedure so that its washability improves. These results may provide a new horizon to design new-generation smart textiles via utilizing controllable wettability.