Effect of polyurethane morphology on blood coagulation.

A series of polyurethanes based on the hard segment MDI and soft segment PTMG were synthesized. The molecular weight of the PTMG was 730, 1000, and 2000, and ethylene diamine was used as chain extender. The fabrication process was varied so as to achieve the maximum disorder (nonequilibrium state) and maximum order, fully annealed. It was demostrated that the "quenched" non-equilibrium state reduces the rate of activation of the intrinsic systems, factor XII pathway, when compared to the fully annealed state. Platelet attachment is primarily affected by phase separation.