Group rings and rings of matrices

Polyester compositions comprising a blend of poly (C2-C4 alkylene terephthalate) with a diepoxy compound and a multiphase composite polymer are disclosed. The multiphase polymer has a first elastomeric phase polymerized from a monomer system including C1-C6 alkyl acrylate as well as crosslinking and graft-linking monomers and a final rigid thermoplastic phase polymerized in the presence of the elastomeric phase.