Study On UV/Thermal Polymerization And Application Of Vegetable Oils

The excessive consumption of global fossil energy and the emission of volatile organic compounds derived from it have caused serious environmental pollution problems.Accompanied by the rapid progress in the level of social science and technology and the rapid depletion of various resources,it has become increasingly serious.In order to promote sustainable development plans,the effective use of renewable energy has become a common concern of researchers and the community in recent years.Vegetable oil has abundant resources in our country,and its price is low,because of its low toxicity and biodegradability,it has been widely used as a typical biomass resource in the chemical industry.Vegetable oils contain multiple unsaturated double bonds and have the structural basis for the construction of UV-cured material systems.Therefore,the construction and application research of UV curing system for vegetable oils was carried out to further realize the rapid solidification of vegetable oils and explore its application in the field of photocurable coatings,which can reduce the excessive dependence of fossil resources on UV-cured coatings.Consequent environmental pollution problems have broadened the scope of application and practical value of natural oils such as tung oil.The paper mainly studies from the following four aspects:(1)In order to explore the photocuring mechanism of tung oil,the peroxide value,the infrared spectrum and nuclear magnetic spectrum of tung oil cured in the different gases were studied.The UV curing behavior of tung oil without catalyst and the system with free radical photoinitiator were also investigated.The results show that the UV curing mechanism of tung oil is mainly oxidative polymerization and free radical polymerization,and the degree of the free radical polymerization reaction is less.Adding free radical photoinitiator 1173 in tung oil UV curing system can obviously promote the oxidative polymerization of tung oil,but it has no obvious effect on the free radical polymerization of tung oil.(2)The photocuring activity of tung oil catalyzed by different photoinitiators was investigated by determining the gelation rate of the system.And the differences in the hardness,apparent characteristics,and solvent resistance of the tung oil UV-cured film and the traditional heat-cured film were explored.The results showed that the TAS has the best priming effect on the UV curing of tung oil,and the optimum dosage was 5 wt%.When 1wt%of free radical photoinitiator PI-BDK or PI-1173 was added,synergistic effects can further promote the photocuring of tung oil.Tung oil UV-cured films prepared under optimal conditions perform similarly to heat-cured films but have better solvent resistance.(3)The effect of irradiation energy,initiator dosage,irradiation time,heating temperature and heating time on the cationic polymerization of methyl eleostearate was studied by NMR spectroscopy.The results showed that the optimal reaction conditions is the amount of triarylsulfonium salt used as cationic photoinitiator is 5 wt%,500 W of high pressure mercury is irradiated for 1 h and then heated in 100 ~oC 3 h.In addition,the cationic polymerization activity of long-chain unsaturated oils does not depend on the number of double bonds but on whether the chemical environment of the double bonds allows the intermediate products to form stable cationic intermediates.(4)In the system of tung oil-based cationic polymers with the TAS as a catalyst,the dynamic mechanical properties,mechanical properties,and contact angles of the cured film were investigated.And the reaction time and post-curing behavior of the cured film were also investigated.By investigating the effect of different monomer types and amounts on the properties of the cured film,the compound tung oil based polymer with the optimal properties was prepared.The results showed that the cured films prepared by heating at 100~oC for 1 h after UV irradiation for 1 h could be completely cured by post curing reaction at room temperature for 24 h.The optimal compounding amount of tung oil-based polymer is70 wt%tung oil,20 wt%divinylbenzene and 10 wt%styrene,and the tensile strength of the cured film is 4.27±0.11 MPa,and the elongation at break is 13.39±2.01%.