METHOD FOR MAKING A IMPACT-RESISTANT VINYL AROMATIC POLYMER COMPOSITION WITH IMPROVED PROPERTIES AND RESULTING COMPOSITIONS

摘要

The invention concerns a method for making a impact-resistant vinyl aromatic polymer composition comprising a vinyl aromatic polymer matrix enclosing rubber nodules, the nodule size distribution being substantially monomode and each of said nodules having at least a vinyl aromatic matrix occlusion or not having such an occlusion. The method comprises a step which consists in polymerising at least one vinyl aromatic monomer: in the presence of at least a rubber (C) whereof at least 22 % of the chains have a molar mass by weight higher than 700000 g/mol expressed in polystyrene equivalents; in the presence of at least a polymerisation initiator (A) with grafting character; at least a chain transfer agent (TC) may be present, the chain transfer agent(s)/initiator(s) mass ratio being less than 1 in the event that at least a chain transfer agent (TC) is present.