Synthesis And Properties Of Waterborne Polyurethane Based On Fluorescent Polyacrylate Chain-Extender

Compared with fluorescent molecules,fluorescent polymers have been widely concerned because of better stability and adjustability.Fluorescent polymers can be used in fluorescent coatings,chemical sensors,fluorescent probes,fluorescence imaging.Fluorescent complexes can be obtained by blending fluorophore with polymers.However,These complexes have the problem of uneven mixing,poor compatibility and stability.In this paper,the fluorescent chromophore is introduced into the polymer chain through the chemical bonding.It aims to obtain a kind of luminescent materials with excellent fluorescence performance and excellent comprehensive performance.In this paper,the first job is designed and synthesized 2-oxo-2H-chromen-8-yl methacrylate(CMA)and anthracen-9-ylmethyl methacrylate(AMMA)and 2-(1,3-dioxo-lH-benzo[de]isoquinolin-2(3H)-yl)ethyl methacrylate(BIEMA).Then Fluorescent polyacrylate diols were prepared by radical polymerization of fluorescent molecules and methyl methacrylate and N-butyl acrylate in the presence of a-thioglycerol as a chain transfer agent.The influence of the molar ratio of initiator to chain transfer agent on the reaction were studied.And the results showed that the three fluorescent polyacrylate diols in butanone could emit blue fluorescence at 365 nm.Further we synthesized fluorescent waterborne polyurethane by Polyaddition reaction of fluorescent polyacrylate diol and PTMG and IPDI and DMPA.The fluorescent polyacrylate diols of molecular weight about 2000 were selected to partially or completely replace 1,4-butanediol as a chain extender.The particle size,molecular weight and its distribution were tested.The thermodynamic properties were characterized by DSC and TGA.The results show that we have successfully synthesized fluorescent waterborne polyurethane based on fluorescent Polyacrylate chain-extender.The optical properties of emulsions and films were characterized by UV-vis and spectrofluorimeter.We found that the emulsion and films of CPUA,AMPUA can emit blue fluorescence.The maximum emission peak of the CPUA emulsion is at 450 nm,and the maximum emission peak of AMPUA is always near 411 nm.Their fluorescence performance is stable,and the content of acrylate(the content of fluorescent groups)have no effect on the luminescent properties.With the increase in acrylate content,the fluorescence of BIEPUA emulsion and film change from blue to blue-green,the emission peak in air and in vacuum appear redshift phenomenon.The fluorescence lifetime are in nanoseconds in vacuum.These phenomena confirmed that the naphthalic anhydride chromogenic groups are easy to be excimer in the polymer matrix.Furthermore,we analyzed the fluorescence properties by blending different proportions of naphthalic anhydride derivatives(BBI)with blank sample of waterborne polyurethane and confirmed the theory of excimer.