Hydroxyl-terminated poly(butadiene) (HTPB; M n 5 2100 g mol 21 ) was capped with 30 and 60 wt % of E-caprolactone to reach amphiphilic triblock copolymers in form of capped poly(butadiene) CPB. The former (CPB30; M n 5 3300 g/mol) is amorphous with a glass temperature of 256 8C. CPB60 (M n 5 4000 g mol 21 ) is semi-crystalline with a melting point of 50 8C and a glass transition at 247 8C. The CPBs, HTPB and polycaprolactone diol (M n 5 2000 g mol 21 ) were used as soft segment components in the preparation of polyurethane elastomers (PUE), using a 1/1 mixture of an MDI prepolymer and uretonimine modified MDI, and hard phase components in form of 1,3-propane diol, 1,4butane diol, and 1,5-pentane diol. CPB-based elastomers with 1,4 butane diol (8 wt %) show hard domains as fringed aggregates with a better connection to the continuous phase than the HTPBbased PUE. The soft segment glass transition temperature (T g ) is at 228 8C for HTPB-based PUE and at 243 8C for those of CPB. The tensile strength of the CPB30&60-based PUE is found between 20 and 30 MPa at an elongation at break of 400% and 550%, respectively.