Preparation And Properties Of Fluorescent Waterborne Polyurethane Based On Cyanostyrene Derivatives

In recent years,the application of environmentally friendly materials has been called for by people.The development and use of environmentally friendly materials has always been the focus of scientific research.The country and society are paying more and more attention to environmentally friendly materials,which not only require superior performance of polymer materials,but also increase environmental protection and cost requirements have attracted much attention in the industry.Water-based polyurethane(WPU)is a material that uses water as a solvent.It meets the human body and environment-friendly requirements,achieves the goal of low cost,and has superior durability.Therefore,it has received extensive attention in the industry.Fluorescent materials are also a current research hotspot because of their broad application prospects.At the same time,water is used as a solvent for polyurethane and a poor solvent for fluorescent molecules,which enhances the fluorescence intensity.The fluorescent material is introduced into the WPU material,and the prepared fluorescent WPU material possesses the performance of optical materials,but also has strong plasticity.This thesis relies on the advantages of WPU materials,introduces cyanostyrene fluorescent materials that are convenient for synthesis,and conducts research on its various properties.Because cyanostyrene has very obvious aggregation-inducing properties,and its synthesis is simple,the yield is high,and it shows yellow color,a small amount of cyanostyrene fluorescent material can make polyurethane with color,which is used in actual fluorescent dye applications.China has great potential.When it is added to polyurethane,it will not only affect the characteristics of the polyurethane itself,but also make the polyurethane having fluorescent characteristics,which has a very large practical effect in the application of polyurethane.Cyanostyrene has unique photophysical and chemical properties,and the study of its fluorescent monomers has attracted more and more attention,such as light-emitting batteries,light-emitting diodes and optical devices.This article first used 4-(2-hydroxyethoxy)benzaldehyde and 1,4-benzene diacetonitrile as raw materials to synthesize cyanostyrene molecules with hydroxyl groups(CS fluorescent small molecules),and used them as chain extenders to introduce in the WPU,a series of fluorescent WPU emulsions with different fluorescent monomer content ware prepared.Secondly,different isocyanates ware changed,the content of fluorescent molecules was fixed,and different isocyanate fluorescent WPU emulsions ware synthesized.Finally,synthetic CS fluorescent molecules and fluorescent polyurethane film were used to perform metal recognition and metal concentration quenching tests,and their fluorescence intensity was recorded.The structure of CS fluorescent small molecule monomers was characterized by infrared and nuclear magnetism.The fluorescence properties of a series of polymers were tested and compared by ultraviolet spectrum,fluorescence spectrum,fluorescence lifetime,and quantum yield.The study found that CS fluorescent small molecules were introduced into WPU polyurethane as a chain extender,and the prepared fluorescent polyurethane material had better emulsion stability and better compatibility.When CS fluorescent molecules ware introduced into the polyurethane segment,the elongation at break is increased,and the thermal weight loss is not significant.The fluorescent polyurethane film obtains an excitation wavelength under a 370 nm ultraviolet lamp,and its fluorescence emission wavelength is around 460 nm,which shows obvious the yellow-green light,the quantum yield has also been improved,and the fluorescence lifetime has also been improved.The prepared fluorescent polyurethane emulsions with different hard segments have good emulsion particle size and stability for cycloaliphatic and aliphatic isocyanates,smaller particle size,elongation at break and tensile stress of HDI-WPU and HMDI-WPU decrease,IPDI-WPU,MDI-WPU,TDI-WPU have similar elongation at break and tensile stress.The ultraviolet excitation wavelength of the prepared fluorescent polyurethane all peaked at 370 nm,the fluorescence emission wavelength of IPDI-WPU,HDI-WPU,TDI-WPU is 455nm,and the fluorescence emission wavelength of HMDI-WPU and MDI-WPU is 526nm.The fluorescence intensity is about 4 times stronger than the first three.The prepared fluorescent molecule has a typical aggregation induction effect,which emits strong yellow-green light when the water volume fraction reaches 60%.Fluorescent molecules have good fluorescence performance.Among 18 metal ion solutions,they have a selective recognition function for Fe³⁺,and with the increase of Fe³⁺concentration,the fluorescence intensity will have a quenching effect,at 1×10^-3?1mol/L in the range,the quenching efficiency and ion concentration show a positive correlation trend,and the detection limit is 10^-3 mol/L.The prepared fluorescent polyurethane emulsion film is similar to a single fluorescent molecule.It has selective recognition of Fe³⁺in the recognition of 18 kinds of metal ion solutions,and the fluorescence intensity of the polyurethane film gradually decreases with the increase of Fe³⁺concentration,showing a positive correlation trend,the detection limit is 10^-3mol/L.