α,ω-Hydroxyl-terminated PBSs were synthesized by melt polycondensation from 1 mol SA and 1.2 mol BDO (Scheme 2) in the presence of Ti(OBu)4 catalyst at 190 °C for 3 h under nitrogen flow and followed by 230 °C under reduced pressure for predetermined times in order to obtain PBS diol with different average-number molecular weights (Mn). The obtained materials were coded as PBS_x, as reported in