Hyperbranched polyester can significantly improve the toughness of epoxy coating, i.e impact resistance, with an increase in the amount of hyperbranched polyester, the impact resistance increases, while the addition level of 15%, the impact resistance increases by 296% and have no impact on the epoxy resin matrix curing condition, rate, and mechanical strength, which is attributed to plasticizing properties of hyperbranched polyester and particles structure in the epoxy resin phase.Weihai CY Dendrimer Technology Co. Ltd forwards from “Hyperbranched Polymers in Cationic Photopolymerization of Epoxy Systems” M. SANGERMANO ‘, G. MALUCELLI1, R. BONGIOVANNI’, A. PFUOLA1 *, A. HARDEN2, and N. REHNBERG2 lDipartimento di Scienza dei Materiali e Ingegneria Chimica Politecnico di ToMo, C.so Duca degli Abruzzi 24 I-1 01 29 Torino, Italy 2Perstorp Specialty Chemicals, 284 80 Perstorp, Sweden POLYMER ENGINEERING AND SCIENCE, AUGUST 2003, Vol. 43, No. 8,1461 -1465