The laws governing the influence of mixed polar and non-polar flexible blocks on the moisture absorption and physicomechanical properties of polyurethane urea were studied, and the relative ratio of these blocks that ensures increased moisture resistance of the material was established.

The laws governing the mechanical behaviour of plasticised polyurethane ureas in a wide range of air relative humidity are studied. It is shown that, in the presence of a plasticiser lowering the solubility of the rigid blocks in the flexible phase of the polymer, there is an increase in the stability of the mechanical characteristics of polyurethane urea on exposure to a humid atmosphere.