Research On The Preparation Process And Properties Of UV-Heat Dual Curable Materials

In this paper,UV-heat dual curable systems were studied,we first synthesized epoxy acrylate ester resin,which can be used in dual curable systems.The rheological behavior of resins with different yield of esterification was investigated,and structure of the resins was characterized through FT-IR spectra.The factors influencing the reaction were discussed,and curing behavior of dual curable systems containing carbon black were also investigated.The results showed that:1.The effect of temperature on viscosity can be described by an Arrhenius type equation,resins with higher yield esterification exhibit higher viscosity,and flow activation energy firstly decrease and then increase with yield esterification.Partial esterified resins,which contain both epoxide groups and unsaturated double bonds,can be used in dual curable systems.2.The crosslinking network density of both UV and heat curable materials are lower,and remarkably increase after dual cured.The conversion yield of both epoxide groups and unsaturated double bonds are lower after heat+UV dual-curing,further analysis shows that it is caused by mobility decreasing of unsaturated double bonds after heat curing.While,the conversion yield of both functional groups is all high after UV+heat dual-cuing.3.In the heat+UV dual curing process,Photopolymerization are inhibited by the polymer networks obtained in the first step,and the effect can be weaken by increasing temperature.Hydroxy groups can promote the curing reaction of aromatic epoxy monoacrylate,but alicyclic epoxy monoacrylate can not be initiated by BDMA.4.The properties of cured films can be improved after dual cured,hard and brittle materials are got after UV+heat dual curable,and heat+UV curable materials are high strength and tough.The properties of cured materials containing GMA are optimum,and materials prepared with 3/4 etherified epoxy acrylate resin have higher tensile strength and elasticity modulus compared with other prepolymer.5.UV curable system containing black carbon can be effectively cured by dual curing styles,UV curing degree of films decrease with content of black carbon and thickness increasing,while,heat curing degree is increased at first,and then decreased after a maximal value.Different thickness of films containing 2.91%carbon black,its gel is between 85 and 92%after UV+heat dual curing,and 79-88%after heat+UV dual curing,however,when the film thickness is 200μm,carbon black content is 2.91%,its gel content can only reach 41.8%after UV curing,and 66.87%after heat curing.