Maleic anhydride (MAH), trans cinnamic acid (AcCin) and ethyl cinnamate (EtCin) were radically graft onto poly(butylene succinate-co-adipate) (PBSA). Samples were prepared in Brabender at 175 degrees C by addition of increasing amounts of MAH, AcCin, EtCin and their combinations, i.e. MAH/AcCin and MAH/EtCin, setting DCP content in the 0.2-0.6 wt% range. Monomer grafting was quantitatively determined by FT-IR. MAH grafting degrees (FD(M)) resulted up to 1 molt Conversely, AcCin grafting degrees (FD(A)) were found almost negligible in all cases. EtCin was found grafted in the 0.3-1.0 mol% range when the binary system MAH/EtCin was applied. Same MAH feeds returned almost doubled MAH grafting degrees (FD(M)) when AcCin was the stoichiometric co-agent, and even three times higher FD(M) when EtCin was the stoichiometric co-agent. On accounts of all the collected results, a kinetic model of the investigated systems is proposed. (C) 2011 Elsevier Ltd. All rights reserved.