Patent ID: 6972311

Claim:
A method for producing an improved polymerized product comprising: polymerizing at least one vinylaromatic monomer in the presence of at least one multifunctional initiator selected from the group consisting of trifunctional and tetrafunctional peroxides, at least one chain transfer agent; and at least one cross-linking agent; and recovering a polymerized product where in polymerizing the monomer, the multifunctional initiator is selected from the group consisting of tri or tetrakis t-alkylperoxycarbonates, tri or tetrakis (polyether peroxycarbonate), tri or tetrakis-(t-butylperoxycarbonyloxy) methane, tri or tetrakis-(t-butylperoxycarbonyloxy) butane, tri or tetrakis (t-amylperoxycarbonyloxy) butane and tri or tetrakis (t-C 4-6 alkyl monoperoxycarbonates), and mixtures thereof.