Poly(aliphatic/aromatic-ester) (PED) multiblock copolymers belong to the class of thermoplastic elastomers (TPEs), characterized by a physical network of semi-crystalline hard segments. The PEDs were modified with e-beam to create an additional network structure. Polymers were evaluated using SEC, WAXS, DSC and quasi-static tensile tests. E-beam irradiation induced a significant increase of molecular weight and tensile strength of the PEDs. This effect, together with the diminished degree of crystallinity can be explained by the formation of chemical crosslinks, which are located in the hard phase segments.