Preparation And Properties Of UV Curable Soybean Oil-based Waterborne Polyurethane Acrylate

With the increasing global environmental pollution problem and the depletion of petroleum resources,renewable resources have become a research hotspot in the field of materials due to their renewability and degradability.Replacing non-renewable petroleum resources with renewable resources is an important direction in the development of materials science.As a kind of high-quality renewable resource,soybean oil has great application potential in the field of materials science,which has aroused the interest of polymer science researchers.China has a long history of planting soybeans and abundant soybean resources,which provides a material basis for the manufacture of soybean oil-based materials.In response to the era call of high efficiency,energy saving,green and environmental protection in the 21st century,water-borne UV curing system stands out among many curing systems because of its advantages of low toxicity,low irritation,less pollution and production safety,and has become a research and development target that is currently welcomed by experts and scholars.Waterborne UV curable coatings combine the advantages of both UV curable coatings and waterborne coatings.dispersant.On the one hand,it eliminates the environmental pollution caused by the use of volatile organic solvents（VOC）in UV curable coatings.On the other hand,it provides a new curing method for waterborne coatings.This graduation thesis is mainly composed of three parts.The first part is the preparation of soybean oil-based polyols containing double bond.Epoxy soybean oil（ESO）with low epoxy value（4.0%）was prepared by peroxyformic acid oxidation with soybean oil（SBO）as raw material,adding formic acid,hydrogen peroxide and concentrated sulfuric acid.Then,using triphenylphosphine（PPh₃）as catalyst,p-hydroxyanisole（MEHQ）as inhibitor,acrylic acid was used to ring-open ESO to prepare acrylated epoxy soybean oil polyols（AESO）with double bonds,which were used as long chain polyols for subsequent UV curing.The raw materials and products were characterized by FT-IR and ¹H-NMR.The effects of molar ratio of epoxy group to acrylic acid,reaction temperature,reaction time,the amount of catalyst and inhibitor on the acid value and esterification rate of acrylic ring-opened epoxy soybean oil were investigated by single controlling variable method,and the optimum conditions for the preparation of acrylated epoxy soybean oil polyols were determined.The results showed that when the molar ratio of epoxy group to acrylic acid was 1:1.5,the reaction temperature was110℃,the reaction time was 8h,the amount of PPh₃ was 1.2wt%and the amount of MEHQ was 0.15wt%,the reaction esterification rate of epoxy soybean oil with acrylic acid ring opening was the best,up to 85%,the hydroxyl value of AESO obtained under this condition is120.26 mg KOH/g.In the second part,soybean oil-based waterborne polyurethane acrylate prepolymer was successfully prepared by step method from toluene diisocyanate（TDI）,acrylated epoxy soybean oil polyol（AESO）,dimethyllpropionic acid（DMPA）,1,4-butanediol（BDO）and hydroxyethyl methacrylate（HEMA）as the raw material,then neutralized by triethylamine（TEA）and emulsified by deionized water.The anionic soybean oil based waterborne polyurethane acrylate（WPUA）emulsion with UV activity was prepared.Finally,the photoinitiator IRG-2959 was added,and the film was cured under the irradiation of ultraviolet lamp after mixing uniformly.The effects of n（TDI）/n（AESO）value,R value（-NCO/-OH molar ratio）,hydrophilic group DMPA content,neutralization degree and solid content on the synthesis of emulsion and the curing properties of the coating were discussed.And a series of test hands such as FT-IR,viscosity,particle size,pencil hardness,adhesion,flexibility,water absorption,stress and strain test,scanning electron microscope（SEM）and thermogravimetric analysis（TG）were investigated.The structure and properties of the emulsion and films were characterized and tested.The third part is to modify the UV-cured soybean oil-based waterborne urethane acrylate by adding epoxy resin（E-51）to it during the synthesis of UV curable soybean oil-based waterborne polyurethane acrylate.When the amount of E-51 was 0,2wt%,4wt%,6wt%,8wt%and 10wt%（the total mass of WPUA resin was used as the benchmark）,the effect of the amount of epoxy E-51 on the emulsion synthesis and the properties of the UV cured film was discussed.The properties of emulsion and UV curable films were tested by FT-IR,viscosity,particle size,pencil hardness,adhesion,flexibility,water absorption,stress strain test,SEM,TG and differential scanning calorimetry（DSC）.