Novel cationic fluoroalkyl-terminated hyperbranched polyurethane (CHBPUF) latex was synthesized by graft reaction of perfluorohexyl ethyl alcohol and hyperbranched polyurethane (CHBPU), which was previously prepared from interaction between hydroxyl-terminated hyperbranched polymer and PU prepolymer manufactured via the acetone process, as well as using neutralization, adding water, and high-speed stirring operations. We characterized the resultants and investigated its surface properties by IR, NMR, XRD, TEM, TGA, DSC, FE-SEM, AFM, XPS, and contact angle measurements, etc. IR and NMR tests confirmed that the fluorinated fragments had been grafted onto the tail end of CHBPU. XRD, TEM, DSC, and FE-SEM results all accounted for there were multi-crystals in CPU, CHBPU and CHBPUF. TGA result showed that thermal stabilities of the CPU, CHBPU, and CHBPUF latex films were enhanced in turn. XPS and AFM analyses demonstrated that the fluorine-containing segments from the CHBPUF terminals were likely to migrate and enrich at the film-air surface of the CHBPUF latex film, which made water contact angle and water absorption of the CHBPUF film be as 108.9° and 13.9%, respectively, compared to those of the CPU film (90.4° and 97.5%). This indicates that water resistance of the CPU film can be efficiently enhanced by fluorinated polyurethane with novel fluoroalkyl-terminated hyperbranched structure and thus CHBPUF latex can find potential application in hydrophobic coating field.
Volume 121, August 2018, Pages 209–217