| abstract |
The present invention relates to a rigid material based on PPO and an aromatic vinyl resin with improved impact strength comprising: n 99 to 20% of a resin (A) consisting of a mixture of PPO and of an aromatic vinyl resin, n 1 to 80% of an impact modifier comprising at least one block copolymer S-B-M in which: n each block is linked to the other by means of a covalent bond or an intermediate molecule linked to one of the blocks by a covalent bond and to the other block by another covalent bond, n M consists of MMA monomers optionally copolymerized with other monomers and comprises at least 50% by weight of methyl methacrylate (MMA), n B is incompatible with the resin (A) and with the M block and its glass transition temperature Tg is less than the temperature for using the rigid material, n S is incompatible with the B block and the M block and its Tg or its melting point m.p. is greater than the Tg of B, n S is compatible with the resin (A). n The aromatic vinyl resin is advantageously polystyrene and the triblock S-B-M consists of polystyrene, polybutadiene and PMMA respectively. |