Water‐based polyurethane dispersions

A general overview is presented of the most relevant and commercially available aqueous polyurethane dispersions (PUDs) and their typical properties. This paper starts with the chemistry and the general composition of standard PUDs and subsequently urethane–acrylic hybrid dispersions are presented with special emphasis on the relation between the obtained morphology and the final material properties. In a section regarding crosslinkable PUDs, the two most frequently applied curing mechanisms are mentioned: firstly the introduction of carbonyl groups into PUDs which can be used for curing at room temperature with amino functional compounds by formation of azomethine moieties, and secondly the introduction of unsaturated fatty acid moieties into PUDs, which enable oxidative curing at ambient conditions. The paper then continues with a section on UV‐curable, acryloyl‐functional PUDs, followed by a section on an interesting new development, namely water‐based polyurethanes with special optic and haptic properties. The paper ends with a section on recently reported modifications of PUDs, including carbon nanotube‐ and graphene‐modified PUDs, PUDs modified with silane coupling agents and PUDs modified with biodegradable moieties. © 2018 Society of Chemical Industry