Non-reactive hydroxyl-terminated hyperbranched polyesters can be used as toughening agent of epoxy resin system (bisphenol A epoxy resin) , which in the form of monodisperse particles disperse in epoxy matrix, play a toughening effect. When the dosage is 10%, it can obviously improve the impact resistance properties and is  2 times than without it. Hyperbranched polyesters in the form of particles disperse in the epoxy systems can reduce crack and play an enhanced effect. Weihai CY Dendrimer Technology Co. Ltd.-Professional Manufacturer for low cost dendritic polymers forwards from “Thermomechanical properties and morphology of blends of a hydeoxy-functionalized polymer and epoxy resin” D.Ratna GPSimon Department of materials engineering manash university, clayton , vic, 3800, Australia Polmer, 2001.42, 8833-8839