Microphase separation in oxyethylene/oxybutylene copolymers with diblock and triblock architectures

EBE and BEB triblock copolymers were prepared and characterized. Microphase separation in the melt state was studied, and the results combined with th ose for EB and BEB copolymers reported previously. The microphase separatio n temperature (MST) was determined from the temperature dependence of SAXS. There was a large difference in MST between the diblock and triblock copol ymers as expected from theory. The Flory-Huggins parameter (chi) was indepe ndent of block architecture for all three series provided that the E block lengths in the EBE copolymers exceeded 65.