EVALUATION OF THE MECHANICAL PROPERTIES OF PRECIPITATED POLYURETHANE FILMS IN REACTIVE AGENTS MEDIUM Segmented poly (ester-urethanes) elastomers based on poly (ethylene diethylene adipate) diols as a soft segment and aromatic diisocyanates in the hard segment were synthesized by a conventional method. The precipitated polyurethane films have been degraded after a limited exposure to reactive agents: 4,4’-methylenebis(phenyl isocyanate) epichlorohydrin and propylene oxide in benzene. The effects on mechanical properties of precipitated polyurethane films were found to be a measure of the degradation due to reactive agents. 4,4’-methylenebis(phenyl isocyanate) and propylene oxide had an increase in the hard segment content which was associated with increased hard domain crystallinity, hardness and improvement in mechanical properties. It is suggested that the superior mechanical performance may be related to interconnecting hard domain texture by cross-linking process. Theis study attempts to correlate the mechanical properties of the precipitated polyurethane films with the nature of the reactive agents. In all cases, the effect of reactive agents was to increase the ultimate tensile strain, except epichlorohydrin.