Hydrodynamic and electrooptic properties of comb-shaped liquid-crystalline copolymers containing cyanobiphenyl mesogenic groups and 0.7-73 mol % acrylic acid units were studied in THF solutions and in isotropic melts. It was established that the degree of polymerization of the copolymers is independent of their composition and lies within 32-93. The degree of folding of the copolymer macromolecules increases with the fraction of acrylic acid units in the copolymer. The electric field birefringence in solutions of the copolymers under study arises due to the orientation of polar cyanobiphenyl groups. The Kerr constant decreases with increasing content of acrylic acid in the copolymers. The temperature dependences of the Kerr constant and the relaxation time of orientational order fluctuations in the vicinity of the isotropic liquid-nematic liquid crystal transition were studied. It was found that the dipole orientation time and the relaxation time of orientational order fluctuations sharply increase with the content of acrylic acid, an observation indicative of an effect of hydrogen bonding on the electrooptic characteristics of the copolymers under study.