Synthesis of integral skinmicrocellular polyurethane elastomers by reacting hydroxyl-terminated aliphatic polyesters with symmetrical diisocyanates, prepolymers of these isocyanates such as derived form p,p'-diphenylmethane diisocyanate and an aliphatic glycol and mixtures thereof, these are polymerized in the presence of an organic blowing agent, and one or more plasticizers such as of the formulae
and
further enhancement of the results is brought about by the presence of catalysts and cell regulating agents, such as dimethylpolysiloxanes; the obtained elastomers are useful, such as for shoe soles and in the manufacture of other products, e.g., vibration dampening devices, floatation devices, gaskets and the like.