| UV-curing technologies have been developed very fast due to their high polymerization rate,low energy consume and low solvent emission.They have been widely applied in the fields of coatings,electronic devices,adhesives,printing and inks.However,the UV cured films suffer from poor surface properties such as hydrophobicity,oleophobicity and inferior resistant to chemicals.It was well known that the fluorine-containing materials are very popular by virtue of their outstanding characteristics of high thermal and chemical stability,excellent hydrophobicity and oleophobicity,low friction and so on.So it will be significant to employ fluorinated materials in UV-curing systems,because it could combine the advantages of UV-curing technologies and the outstanding properties of fluorinated materials together.However,the fluorinated small molecular could not be polymerized fully in the UV-curing process,which will not easily to form a cross-linked structure leading the migration of small molecules from bulk to surface.The cured films will lose theintrinsic properties of fluorinated material with the time.However,the difficulties could be overcome by introducing fluorinated structure into polymer or oligomer,three type of fluorinated oligomers were syethesized for the UV-curing system in this paper,the main contents and conclusions as follows:1.Synthesis of polymerizable fluorinated acrylic oligomers and its UV curing properties.A series of novel polymerizable fluorinated acrylic oligomers with different fluorine content was successfully synthesized by ring-opening reaction of acrylic and the product that polymerized by ethyl methacrylate,n-butyl acrylate,glycidyl methacrylate,and dodecafluoroheptyl methacrylate.The UV-curing coatings were prepared with various obtained polymerizable fluorinated acrylic oligomers.The influences of different fluorine content on the properties of cured films were investigated by the tests of hydrophobicity,oleophobicity,thermal stability,water absorption,hardness,chemical resistance and so on.The results showed that the photopolymerization rate and the final conversion rate of the coating would increased with the increase of fluorine content in the cured film.The water contact angle of cured films increased from78.5° to 104.5°,n-hexadecane contact angles increased from 12.3° to 43.4°,and the water absorption decreased from 1.27% to 0.63% with increasing the fluorine content of the cured films from 0 wt% to 5.7 wt%.In addition,thermal stability and chemical resistance of the cured films were improved obviously.2.Synthesis of polymerizable fluorinated polyurethane oligomer and its UV-curing properties.The dodecafluoroheptyl diol was firstly synthesized bydodecafluoroheptyl acrylate and diethanol amine via Michael addition,then the polymerizable fluorinated polyurethane oligomer was fabricated by the obtained dodecafluoroheptyl diol,isophorone diisocyanate and 2-hydroxyethyl acrylate.The UV-cuing coatings were prepared with various amounts of the obtained oligomer.The effects of the amounts of fluorinated polyurethane oligomer on the properties of cured films were investigated.The results showed photopolymerization rate of the coating will increase with the increase of the fluorinated oligomer content.And the water contact angle of cured films increased from 53.5° to 98.8°,the water absorption decreased from 1.32% to0.55%,the Shore D hardness increased from 43.3 HD to 90.3 HD,the wear resistance increased from 45 r to 145 r with the fluorinated polyurethane oligomer increasing from 0 wt% to 20 wt%.In addition,the chemical resistance of the cured films was also improved obviously.3.Synthesis of polymerizable fluorinated epoxy acrylate oligomers and its UV-curing properties.The intermediate product FC-IPDI were synthesized by N-ethyl,n-hydroxyethyl perfluorooctane sulfonamide and isophorone diisocyanate according to the molar ratio of 1:1,epoxy acrylate were synthesized by the epoxy resin and acrylic acid with the molar ratio of 1:2.A series of novel polymerizable fluorinated acrylic oligomers with different fluorine content was successfully synthesized by FC-IPDI and epoxy acrylate.The UV curable coatings were prepared with various varieties of the obtained polymerizable fluorinated epoxy acrylate oligomers.The results showed that thewater contact angle of cured films increased from 38.9° to 112.7°,the water absorption decreased from 1.8% to 1.1%,the hardness of the coating increased from 57 HD to 86 HD,the impact resistance reduced to 90 cm from 120 cm,and the adhesion decreased from 1 to 2 with the molar ratio of FC-IPDI and EA increased from 0:1.0 to 0.4:1.0 of the fluorinated oligomer.In addition,the chemical resistance and thermal stability of the cured films were improved obviously compared with fluorine-free cured film. |
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