Non-isocyanate strategy for anionically stabilized water-borne polyurea dispersions and coatings

\u3cp\u3eAn isocyanate-free strategy for the preparation of anionically stabilized water-borne polyurea (PU) dispersions was developed with diamines, dicarbamates, and dianhydrides as monomers. Poly(amic acid urea)s (PAAUs) with number average molecular weights up to 34 kDa were synthesized from ethylenediaminetetraacetic dianhydride and diamine-functional PUs. The latter were produced from polymerization of dicarbamates and diamines. The factors that affected the particle sizes of the corresponding PAAU dispersions were investigated. Water-borne PAAU coatings cured at elevated temperatures exhibited much better material properties than those cured at 50 °C as a result of crosslinking due to amine/carboxylic acid reactions and noncyclic imidization.\u3c/p\u3