Polymers by [3 + 2] cycloaddition, 6.^† Polyureas with novel structure elements

The synthesis of new diisocyanates via “criss-cross” cycloaddition between aromatic aldazines and diisocyanates as well as their conversion to polyureas is described. The new monomers and polymers contain the heterocyclic 1,3,5,7-tetraazabicyclo[3.3.0]octane-2,6-dione system in their backbone. The polymers are characterized by spectroscopic techniques, DSC, thermogravimetry, and GPC. The influence of the new structure element on solubility, glass transition temperature, crystallinity, and thermal stability is discussed.