Study On Preparation And Properties Of The Rapeseed Oil-based UV-curable Coating And Polyurethane

With the increasing depletion of oil resources,renewable raw materials to prepare the polymer material has become an inevitable trend.Natural vegetable oils are a class of natural compounds,because of its wide variety of sources,processing costs,environmentally friendly products biodegradable,and contains large amounts of group that could modified,favored by many researchers.It has important theoretical and practical significance in expanding renewable application of the resource sector.In this paper,UV-curable coating and polyurethane coating were prepared by rapeseed oil,isosorbide and castor oil derivatives undecylenate as the starting material.The following research areas were carried out:(1)The preparation of undecylenate modified rapeseed oil-based branched polyene prepolymer and UV curingFirst,the use of rapeseed oil and undecylenate synthetic rapeseed oil-based branched polyene prepolymer.Then,the UV-curable films were successfully prepared through react with different thiols under the photoinitiator and UV light.The thiols contains pentaerythritol tetrakis 3-mercapto propionate,trimethylol propane tri-3-mercapto propionate,1,2-ethanedithiol.By nuclear magnetic resonance(NMR)and Fourier transform infrared(FTIR),not only characterize the synthetic intermediate monomer,and curing kinetics was studied.The mechanical and thermal properties of the coating were tested by Dynamic Mechanical Analyzer(DMA)and Thermal Gravimetric Analyzer(TGA).The water resistance and toluene swelling rate of the films were also tested.Research indicates that the conversion rate of the carbon-carbon double bond and thiol group were 79%and 72%in the polymerization time at 30min.Different thiols has little effect on the thermal stability of the coating.With the increase in the number of Mercaptofunctional,enhancing the mechanical properties and water resistance of the coating,but to reduce the rate of swelling in toluene.(2)Synthesis of undecylenate modified isosorbide reactive monomer and UV curingThe use of isosorbide and undecylenate synthetic isosorbide-based reactive monomer,whcih the amount of 10wt%was added to the rapeseed oil-based branched polyene prepolymer.Last,the UV-curable film was successfully prepared through react with pentaerythritol tetrakis 3-mercapto propionate.Isosorbide-based reactive monomer was characterized by NMR and FTIR.The mechanical and thermal properties of the coating were tested by DMA and TGA.The water resistance and toluene swelling rate of the films were also tested.It was found that the maximum storage modulus and glass transition temperature(T_g)of UV-curable coating were1657MPa and 6.5?,and water absorption is only 2.9%after 168 hours.(3)Preparation and Properties undecylenate modified rapeseed oil-based branched polyols and polyurethaneEach containing hydroxyl number 6,10,12 and 14 The rapeseed oil-based polyols were synthesized,using rapeseed oil,10-undecenoic acid as raw materials,then a series of rapeseed oil-based polyurethane with different crosslinking density were prepared through react with isophorone diisocyanate.The structures of rapeseed oil-based polyols produces were characterized by NMR.And the properties of rapeseed oil-based polyurethane films were characterized by dynamic mechanical analysis,thermal gravimetric analysis and the solvent-swelling test,respectively.The results show that the elastic strength of polyurethanes films decreases with the incensement of rapeseed oil-based polyol hydroxyl content,and the water absorption and toluene swelling ratio is also decreased.However,the different degree of crosslinking polyurethanes has little effect on the thermal stability of polyurethane films.