The electrochemically activated direct introduction of CO2 into poly(vinyl chloride), poly(vinyl bromide) and polybutadiene to form the corresponding acrylic acid copolymers is shown. It is demonstrated that the maximum extent of carboxylation is attained in the case of poly(vinyl chloride), when conducting controlled-potential electrolysis in dimethylformamide using a platinum cathode and sacrificial anode in an undivided cell. Possible pathways for the explored reactions are suggested.