text: The disadvantages of PUDs are being improved by research. Hybridization using other materials and techniques is one such area. PUDs that are waterborne and UV curable are being intensely researched with well over 100 research papers produced in the 2000-2020 time period. Waterborne PUD- Acrylates based on epoxidized soybean oil that is also UV curable have been produced and are feasible. The nature of the acrylate affects the properties. One use of hybrids is in textile finishes.
  As ionic centers are introduced with waterborne PUDs, the water resistance and uptake in the final film has been studied extensively. The nature of the polyol and the level of COOH groups and hydrophobic modification with other moieties can improve this property. Polyester polyols give the biggest improvements. Polycarbonate polyols also enhance properties, especially if the polycarbonate is also fluorinated. Reinforcing PUDs with nanomaterials also improves properties, as does silicone modification.
  To make PUDs more hydrophobic and water repellent and thus remove a weakness, a number of techniques have been researched. One way is to add hydroxyethyl acrylate to the polyol reacting with isocyanate. Once the PUD is made it will have terminal double bond functionality from the acrylate. This may now be copolymerized with a very hydrophobic acrylate such as stearyl acrylate using free radical techniques. This long alkyl chain introduced confers hydrophobicity.
  Another method of hybridization is to make a PUD that is both anionic but with a very substantial nonionic modification utilizing a polyether polyol based on ethylene oxide. In addition, a silicone diol maybe incorporated.
  As epoxy resins have some outstanding properties, research using epoxy to modify PUD is taking place.
  PUDs that are based on thiol rather than hydroxyl and also modified with both acrylate as well as epoxy functionality have been produced and researched.
  As PUDs are resin dispersed in water, when cast as a film and dried they are inherently high gloss. They can be designed to be matte/flat by incorporating siloxane functionality.
  Since PUDs are usually considered green and environmentally friendly, techniques being researched also include capturing carbon dioxide from the atmosphere to make the raw materials and then further synthesis.