Structural and Rheo-Optical Characterization of Random Bicomponent Networks Prepared of Hydroxyl-Telechelic Polyisobutylene and Polytetrahydrofuran
Abstract The structure of a bicomponent network prepared of hydroxyl-telechelic polyisobutylene (HO—PIB—OH) and polytetrahydrofuran (HO—PTHF—OH) has been characterized by small-angle and wide-angle x-ray scattering, birefringence, and differential scanning Calorimetry. A single phase random network was obtained by endlinking HO—PIB—OH/HO—PTHF—OH mixtures using triphenyl methane triisocyanate (TTI) as a crosslinking agent. A small-angle x-ray scattering peak was observed in the PIB networks as well as in the PIB/PTHF bicomponent networks. The glass transition temperature of the random bicomponent network increased with decreasing PTHF molecular weight as the network became tighter. Network tensile properties were analyzed in terms of Gaussian and non-Gaussian network models. The stress-optical law was tested for random networks by measuring the variation of birefringence and stress as a function of elongation. Author to whom correspondence should be addressed. Present Address: Exxon Chemical Co. , Baytown Polymer Research Center, Baytown, TX 77520.