Abstract: The present invention relates to a stable polymer composition comprising a first polymer and a second polymer, which second polymer is not compatible with the first polymer, and an amount of a copolymer comprising at least one block of a polyalkadiene and at least one block of random poly(aromatic vinyl-acrylonitrile), and in which the ratio of the block copolymer to the total polymer composition is between 1:500 and 1:50. Besides, the invention relates to the use of the above block copolymer as compatibilizer and/or as modifier for the mechanical properties of polymer compositions.

Abstract: The present invention relates to a block copolymer comprising at least one polyalkadiene block which may or may not be hydrogenated and at least one random (aromatic vinyl compound-co-maleic anhydride) block. Besides, the invention relates to a stable polymer composition comprising a continuous phase formed by a first polymer and a phase dispersed therein of a second polymer, which second polymer is not compatible with the first polymer, and an amount of the block copolymer according to the invention, the ratio of the block copolymer to the second polymer ranging between 1:50 and 1:5. Finally, the invention relates to the use of the block copolymers according to the invention as compatibilizer and/or as modifier for the mechanical properties of polymer compositions.

Abstract: A copolymer of a lactone and a polycyclic carbonate is prepared by heating a monomer of a lactone with a polycyclic carbonate having two cyclic structures including a carbonate group at elevated temperatures less than 200 degrees Centigrade in the presence of a catalyst. The described copolymers evidence excellent mechanical properties, good resorption velocity and do not disintegrate upon degradation into materials of high crystallinity.