AbstractA novel class of liquid rubber comprises bis(4‐hydroxybenzoate)‐terminated poly(tetrahydrofuran), which reacts with bisphenol A diglycidyl ether to form segmented liquid rubbers with poly(tetrahydrofuran) and poly(hydroxyether) segments. In anhydride‐cured epoxy resins such segmented liquid rubbers afford improved toughness. Diol‐ and bis(hydroxybenzoate)‐terminated poly(tetrahydrofuran)‐based liquid rubbers are compared. It is possible to control the polymer morphology by the variation of the molecular architecture of segmented poly(tetrahydrofuran)‐based liquid rubbers. The average size of the dispersed rubber phases depends on the molecular weight of the segmented liquid rubbers and correlates with impact strength