Chemical Modification Of Tung Oil Via Ultraviolet Photocatalysis And Its Application In UV Curing System

Excessive global consumption of fossil resources and the resulting environmental pollution problems not only showcase an unfavorable effect on our surroundings,but also limit the development of organic polymer industry based on fossil materials.Biomass,as a renewable resource,has attracted more and more scholars attention.Therefore,many researchers put emphasis on the development of new and high performance materials from biomass resources to replace traditional petroleum-based feed stocks.Vegetable oil,with 1-3 unsaturated double bonds,theoretically has the structural basis for the construction of UV curing system and can be used to synthesize biomaterials,which not only can effectively solve the resources and environmental problems for the needs of sustainable development in the field of UV curng fields,but also expand the application of vegetable oil,increasing its additional value,and help raise farmers incoming.Therefore,the study on the modification of vegetable oil has very high theoretical and practical value.In this paper,tung oil was regarded as the main research subject,to prepare a series of tung oil based UV curing materials and explore its UV curing activity.This article is mainly divided into four chapters,and the main content is as follows:?1?Preparation and characterization of tung oil based urushiol analogues catalyzed by acid ionic liquid.Firstly,eleostearic acid glyceride?the main component of tung oil?was transformed to methyl eleostearate?ME?by transesterification,and the reaction product was separated and purified by silver nitrate silica gel column to obtain pure ME,and then reacted with catechol?CAT?via Friedel-Crafts alkylation using SO₃H-functionalized ionic liquid as catalyst.The alkylation products?CAT-ME?similar to urushiol were successfully synthesized,and confirmed by the characterization results of fourier transform infrared spectroscopy?FT-IR?,ultraviolet-visible spectroscopy?UV-vis?,nuclear magnetic resonance spectroscopy?NMR?and liquid chromatography-mass spectroscopy?LC-MS?.?2?Preparation and characterization of tung oil based urushiol analogues catalyzed by photoinitiators using UV-light as source.Firstly,tung oil was converted to methyl eleostearate by transesterification,and then methyl eleostearate was used to prepare urushiol analogues via UV irradiation.Then,the effects of photoinitiators,UV lamp power,reaction time,and solvent were investigated via single-factor experiment,and the best preparation technology of urushiol analogues was obtained.As a result,the optimum condition for urushiol analogues preparation was:?i?triarylsulfonium salts?TAS?was the optimal catalyst and the optimum adding amount was 5%;?ii?the power of UV light had no significant effect on the yield of CAT-ME,as long as meeting a condition that TAS could be initiated with a certain intensity of UV light?100W?;?iii?the optimum reaction time was 8min;?iv?the optimum solvent was aceton.And the largest yield of CAT-ME was 71%.In addition,the structure of alkylation products?CAT-ME?was also confirmed and characterized by FT-IR,UV-vis,NMR and LC-MS methods.?3?The photoactivity of urushiol analogues?CAT-ME?and its application in UV curing system were also discussed in this paper.Firstly,by comparation of different curing conditions,such as rome temperature,heating?80 ??and UV-irradiation,it was found that CAT-ME could not be solidified into a completed film,due to lacking of biological enzyme,which is a main component in raw lacquer.Then the effect of urushiol analogues?CAT-ME?on polyurethane-acrylate?PUA?films was also explored,including photoinitiators,reactive diluents and the additive amount of CAT-ME.The results showed that PI-819 was the best photoinitiator,the optimum proportion of HEMA:HDDA was 10:10-14:6,and the optimal proportion of CAT-ME was 5-15%.In addition,the UV-cured polyurethane films mixed with CAT-ME had excellent mechanical property and thermal stability,and the gel fraction of the film mixed with 15%CAT-ME reached 99.5%,the tensile strength was up to 25.07MPa while the breaking elongation increased by 4.57%,and SEM displayed that the surface of the film was relatively smooth and flat.?4?Preparation and characterization of tung oil based polyols via UV irradiation and its application in hyperbranched resins.Firstly,the prepared methyl eleostearate was used to synthesize epoxidized methyl eleostearat by reaction with hydrogen peroxide and acetic acid under the catalysis of concentrated phosphoric acid.Then,epoxidized methyl eleostearat was reacted with diethanolamine?DEA?to prepare tung oil based polyols under UV irradiation using triarylsulfonium salts as catalytst.Lastly,a UV-curable hyperbranched polyurethane acrylate dispersions was prepared by a two-step procedure based on tung oil based polyols,isophorone diisocyanate?IPDI?,and hydroxyethyl methacrylate?HEMA?with dibutyltin dilaurate?DBTAL?as catalyst.The results of this chapter is as follows:?i?the optimum conditions for the epoxidation of methyl eleostearate were as follows:temperature 55 ?,reaction time 6 h,methyl eleostearate:acetic acid:hydrogen peroxide?concentration 30%?=10:8.8:22?mass ratio?,and the epoxy value of epoxidized methyl eleostearate was 1.32;?ii?the hydroxyl value of the prepared tung oil based polyols was599.54 mgKOH/g and the average relative molecular mass was 544,which indicated that two epoxy groups in the structure of epoxidized methyl eleostearate were involved in the ring-opening reaction;?iii?the tung oil based hyperbranched polyurethane acrylate dispersions had excellent curing performance and the cured film had superior mechanical property and thermal stability,and the gel fraction reached 98%,the tensile strength was up to 4.1 MPa while the breaking elongation increased by 54%,which could supersede part of traditional petroleum-based UV curing materials.