For the first time emulsion polymerization of polyangelicalactone with styrene was carried out. Block copolymers with a molecular weight of 40000-1000000 and containing 5-40 weight % of styrene were prepared. Polymerization rate constants were evaluated. Mechanical properties were evaluated after the copolymers were cured. The cured block copolymers satisfy the basic requirements for high impact polystyrene, and they are biodegradable.