CHARACTERIZATION OF POLYURETHANE NETWORK ELASTOMERS

Polyester urethane network elastomers with incorporated hard segment o ligomers have been prepared by poly(ethylene adipate)glycol (PEA), 2,4 -tolylene diisocyanate (TDI), and 1,4-butanediol(BD). These hard segme nt oligomers were hydroxy-terminated oligomers ([BD-TDI]n-BD; n=1,3), obtained by reacting BD with TDI. Concentrations of allophanate as a c ross-linking site were determined by the amine degradation method. Har d segment moieties were obtained by a novel selective hydrolysis of so ft segments in the elastomers. Molecular weight distributions of hard segment were measured by means of GPC. Mechanical and thermal properti es were measured. Dependence of rubber elasticity on physical cross-li nking between normal elastomers and the elastomers with incorporated h ard segment oligomers were discussed.