Preparation And Properties Of Uv Curable Waterborne Polyurethane Acrylate

Due to the combination of the high efficiency of UV-curable coatings and environmental friendly of waterborne coatings,the UV-curable waterborne coatings are widely used in many fields.Polyurethane acrylates have gradually become the hotspot of materials research because of their comprehensive properties such as good mechanical properties,flexibility,weatherability and so on.In this paper,polyacrylates(PAA)with different carboxyl and hydroxyl content on their side chains were synthesized via free radical solution polymerization of acrylic acid(AA),methyl methacrylate(MMA),butyl acrylate(BA),hydroxyethyl acrylate(HEA)and styrene(St).Then,three polyether polyurethane acrylates were synthesized and named as PEPUA1,PEPUA2 and PEPUA3 using isophorone isocyanate(IPDI),polyether polyol(CHE-204),HEA and different polyacrylates(PAA).Also,three non-polyether polyurethane acrylates were systhesized and labled as PUA1,PUA2,PUA3 using IPDI,HEA and different polyacrylates(PAA).The structure of synthetic products was characterized by Fourier transform infrared spectroscopy(FTIR).And the mechanical properties of the two systems after curing were tested by dynamic mechanical analysis(DMA).The thermal stability,glass transition temperature,water resistance and other basic properties of films were also evaluated.Furthermore,the effects of photoinitiator concentration and type,monomers and irradiation intensity on the kinetics of photo-curing reaction of the two systems were investigated in detail.It was observed that the mechanical properties,thermal stability and physical properties of the two systems after curing were significantly improved with the increase of content of HEA monomer.In comparison,polyether polyurethane acrylates possessed better comprehensive performance.In order to get better coating performance,PEPUA1 resin was selected as a polymeric emulsifier.Then,four kinds of composite emulsions were prepared by blending with different contents of epoxy acrylate(EA).The effect of the content of EA on the properties of emulsions and films was mainly studied.The results showed that particle size of the emulsions becomed larger and the stability was decreased as the increase of EA content.In addition,the mechanical properties of the films were greatly improved,and the water resistance of the films was obviously better.