Preparation And Investigation The Properties Of Bio-based UV Curing Coatings

UV curing coating is a kind of coatings which can be quickly cured under ultraviolet light,it has the advantages of fast curing,energy saving and less pollution.Therefore,searching for alternatives to petroleum derivatives has become a trend of sustainable development under the situation of the shortage of petroleum resources and environmental pollution problem.Bio-based materials are gradually favored by researchers because of their abundance in nature and low price.Bio-based materials were widely used in many fields for its degradability and low cost in preparation process.The vegetable oil and phenolic acids occupied the majority of the bio-based raw materials,and their structures contain a large number of functional groups,which provide wider space for the development and full use of biological resources.In this paper,isosorbide,vegetable oil and tannic acid are used as starting materials to prepare different UV curing coatings,and the main research work is as below.(1)Preparation and investigation the properties of rapeseed oil-based UV curing coatingsFirst,the rapeseed oil-based gepolyene prepolymer was synthesized by using rapeseed oil and mercaptoethanol.The castor oil-based thiol was synthesized by the use of castor oil and sulfhydryl propionic acid.Finally,the UV curing coatings were successfully prepared by using rapeseed oil-base alkene monomers reacted with different mercaptan monomers(pentaerythritol 4-3-mercapto propionic acid ester,trimethylolpropane 3-3-sulphur propionate,castor oil-based mercaptan)under light initiator and ultraviolet light.The structure of monomers was characterized by nuclear magnetic(NMR)and infrared(IR).The mechanical properties and thermal performance of films were characterized by dynamic thermal mechanical analyzer(DMA),differential scanning calorimetry(DSC)and thermo-gravimetric analyzer(TGA),and the gel rate,water resistance,toluene swelling rate were also investigated.The results show that different mercaptan monomers have little influence on the thermal stability of the films.With the increase of the number of thiol in the monomers,the storage modulus of the films increased from 820 MPa to 1800 MPa.The water resistance of the films enhanced,while the swelling rate of toluene was decreased.(2)Preparation and investigation the properties of gallic acid-based UV curing coatingsThe gallic acid-based monomer was synthesized by using gallic acid,acryloyl chloride and allyl bromide.The soybean oil-based monomers were synthesized from epoxy-soybean oil,acrylic acid and acryloyl chloride,UV curing coatings were prepared by using the two kinds of monomers reacted with castor oil-based thiol in different mass ratio.The structure of monomers was characterized by nuclear magnetic(NMR)and infrared(IR),the mechanical and thermal properties of films were characterized by dynamic thermal mechanical analyzer(DMA),differential scanning calorimetry(DSC)and thermo-gravimetric analyzer(TGA).The gel rate,water resistance,toluene swelling rate were also investigated.The results show that the maximum storage modulus of the UV curing coatings reached 1657 MPa,the maximum glass transition temperature(T_g)of the coatings tested by DMA is 31°C.The maximum decomposition rate of the films can increase to 370°C.(3)Preparation and investigation the properties of tannic acid-based UV curing coatingsThe tannic acid-based monomer was synthesized by using tannic acid and methacrylic acid glycol.Then,an isosorbide-based active diluent was synthesized from isosorbide and undecenyl chloride,a series of UV curing coatings were prepared by using tannic acid-based monomer reacted with castor oil-based thiol and add the isosorbide-based active diluent with the content of 0%,30%,40%,50%and 60%respectively.The structure of tannic acid-based monomer and isosorbide-based active diluent were characterized by nuclear magnetic(NMR)and infrared(IR).The mechanical properties and thermal performance of films were characterized by dynamic thermal mechanical analyzer(DMA),differential scanning calorimetry(DSC)and thermo-gravimetric analyzer(TGA),the gel rate,water resistance,toluene swelling rate were also investigated.The results show that with the increase of isosorbide-based active diluents content,storage modulus of UV curing coatings can reach 2553 MPa and T_g measured by DMA can reaches 29°C,the rigidity gradually increased,while the water absorption and toluene swelling rate decreased,all of the coatings had good water resistance.When the content of isosorbide-based active diluent reached 60%,the thermal stability and mechanical properties of the films were decreased.