POLYURETHANE ELASTOMERS BASED ON NOVEL POLYETHER MACRODIOLS AND MDI - SYNTHESIS, MECHANICAL-PROPERTIES, AND RESISTANCE TO HYDROLYSIS AND OXIDATION

Novel polyurethane elastomers based on 4,4'-diphenylmethanediisocyanate, 1,4-butanediol, and polyether macrodiols that have 6, 8, or 10 methylene groups between the ether oxygens were prepared by two-step solution polymerization. Their mechanical properties and degradation resistance were compared with poly (tetramethylene oxide) -based polyurethanes. The new polyurethanes were more resistant to hydrolysis and to hydrogen peroxide-induced oxidation than were the poly(tetramethylene oxide)-based materials. The poly(octamethylene oxide) -based polyurethane displayed good resistance to sodium hypochlorite. 1,2-Diaminoethane chain-extended polyurethane-ureas were also prepared using the macrodiols poly (hexamethylene oxide) and poly (octamethylene oxide). They were not thermally processable or solvent-castable. Bulk synthesis of novel polyether polyurethanes yielded, in some cases, materials with improved mechanical properties compared with their solution-polymerized counterparts. The outcome of the bulk syntheses was highly dependent, however, on reaction conditions and stoichiometry.