Abstract: The present invention refers to an improved composition for the production of vinyl aromatic polymers modified with rubber, in which a substantial impact resistance improvement of the final product is produced by the incorporation of a structure modifying additive in different steps of the polymerization, preferably during the process of co-continuity of phases and specially, during the inversion of phases interval. The additive is an insaturated compound of formula: wherein: R1, R3 each represents a saturated or unsaturated chain from C1 to C18, being equal or different from one another, R2, R4, R5 each represent, hydrogen, halogen or a carbonated chain from C1 to C18, being equal or different from one another, “n” being an integer number equal or grater than 1 and where the additive can be used either without mixing it in a concentration within the range of 0.025 to 5% in weight, or in mixtures with low molecular weight polymers in a weight ratio preferably from 5/1 to 1/5.

Abstract: This invention describes the obtainment of impact-resistant materials from a block copolymer that comprises as monomers an alkadiene (conjugated diene) and a vinyl aromatic compound, which is used as impact modifier to obtain such materials and in which, at least, one of the blocks of the vinyl aromatic compound is polydisperse. The invention allows obtaining morphologies such as rods, points or capsules by incorporating such copolymer into a polymeric matrix derived from vinyl aromatic monomers independently from other agents such as chain transfer agents, and achieving increases, in the impact values up to 50% through the use of the copolymer of this invention.

Abstract: This invention describes the obtainment of impact-resistant materials from a block copolymer that comprises as monomers an alkadiene (conjugated diene) and a vinyl aromatic compound, which is used as impact modifier to obtain such materials and in which, at least, one of the blocks of the vinyl aromatic compound is polydisperse. The invention allows obtaining morphologies such as rods, points or capsules by incorporating such copolymer into a polymeric matrix derived from vinyl aromatic monomers independently from other agents such as chain transfer agents, and achieving increases, in the impact values up to 50% through the use of the copolymer of this invention.