A hyperbranched polyetherketone and a heat-resistant blend of polyvinylchloride with the same. The polyetherketone is synthesized by self-polycondensation of 3,5-bis[4-[(2,3,4,5,6-pentafluorophenyl)carbonyl]phenoxy]-4-hydroxybenzoph enone or 3,5-difluoro-4-hydroxybenzophenone, and then substituting 50 to 80 mole % of fluorine atoms present in the side chains and ends of the PEK molecule by polar groups. In addition, a blend of polyvinylchloride can be manufactured using the hyperbranched polyetherketone by a melt blending technique applicable for industrial purpose at a temperature of 180 to 120.degree. C., and thus the blend of polyvinylchloride with the polyetherketone can be applied to high temperature end-use products such as hot water pipes.