The copolymers of n-butyl acrylate

methyl methacrylate and 2-hydroxypropyl acrylate were prepared by activators regenerated by electron transfer atom transfer radical polymerization(ARGET ATRP)using the hexa-functional and mono-functional initiators and 0.01% low concentration of complex catalyst. The molecular structure

copolymer composition and glass transition behavior of the polymers were characterized by refractive index-multi angle laser light scattering-viscometer triple detection gel permeation chromatography

hydrogen proton nuclear resonance (1H NMR) and differential scanning calorimetry (DSC)

respectively. The obtained polymers were formulated into solutions for coating. Rheology tests revealed that viscosity of star polymers was the lowest. The viscosity decreasing efficiency was more remarkable at high solids contents. Under suitable spray viscosity

the solid content of star copolymer increased by 10% compared with commercial acrylic resin obtained by conventional free radical polymerization. The tack-free time of varnish composed of star polymers and isocyanate curing agent was very short. The mechanical properties of coating film reached a good level.