Preparation And Luminescence Properties Of Fluorescent Anti-Counterfeiting Fiber Containing Eu(?)

With the rapid development of the economy,counterfeit products are emergingoneafteranother,whichputshigherrequirementson anti-counterfeiting technology.Fluorescent anti-counterfeiting fibers are widely used in the fields of banknotes,securities,and security of documents due to their advantages of good concealment and easy identification.Rare earth polymer materials have become the first choice for fluorescent anti-counterfeiting fiber materials because they have the unique optical properties of rare earth complex and good mechanical and processing properties of polymers.However,the rare earth polymer-based fluorescent anti-counterfeit fibers prepared at present have many problems such as agglomeration of fluorescent particles or poor compatibility with polymers,they are vulnerable to external influence,resulting in weakening or disappearance of fluorescence intensity.Based on this,the doped nano-fluorescent fibers with polyvinyl alcohol as polymer matrix were prepared by electrospinning to improve the agglomeration of fluorescent particles and achieve nano-dispersion of fluorescent particles in the fibers.Secondly,the copolymer Eu-PVA was prepared by free radical polymerization,and the bonded fluorescent anti-counterfeiting fibers were prepared by electrospinning to further improve the fluorescence quenching Phenomenon.Main contents of the study are:?1?Using Eu?TTA?₂?Phen?MAA as rare earth complex and polyvinyl alcohol?PVA?as polymer matrix,the doped fluorescent anti-counterfeiting fiber was prepared by electrospinning.The results showed that the nanofibers were randomly arranged,the surface of the fibers was smooth,the diameter distribution of the fibers was uniform,and the average diameter was about 150nm.With the increase of the content of the complex,the luminescence intensity of Eu?TTA?₂?Phen?MAA/PVA was significantly enhanced with quenching concentration of 8wt%.Under the excitation of 365 nm ultraviolet light,the nanofibers exhibited strong characteristic emission peaks of Eu³⁺at 612 nm.The fluorescence lifetime was 0.642 ms,and the initial thermal decomposition temperature was 245.3?.?2?The copolymerEu-PVAc wassynthesizedby free radical polymerization using Eu?TTA?₂?Phen?MAA as complex and vinyl acetate?VAc?as polymerization monomer and azodiisobutyronitrile?AIBN?as initiator,and then the copolymer Eu-PVA was prepared by alcoholysis.The characterization results showed that the complex was successfully bonded to the polyvinyl alcohol polymer chain and the initial thermal decomposition temperature of the copolymer was obtained.The quenching concentration of the copolymer Eu-PVA was 16wt%,and the fluorescence quenching phenomenon was greatly improved.?3?Based on the excellent fluorescence stability of the copolymer Eu-PVA,the bonded fluorescent anti-counterfeitingfibers wereprepared by electrospinning and mixed with pulp to prepare fluorescent anti-counterfeiting paper.The results show that when the excitation wavelength is 396 nm,the characteristic emission peak of Eu³⁺appears at 612 nm,the fluorescence lifetime is 0.667 ms,and the initial thermal decomposition temperature is 293?.With the increase of the complex content,the luminescence intensity of the bonded fluorescent fibers increases significantly,and the quenching concentration is16wt%.Compared with the doped fluorescent anti-counterfeiting fibers,the fluorescence quenching phenomenon is greatly improved.The prepared fluorescent anti-counterfeiting paper exhibited pure red light emission under 365nm excitation,showing good anti-counterfeiting effect.