Preparation And Performance Research On Yellowing Inhibition Of Coumarin Fluorescent Polymers

For the properties of high bulk,opacity,stiffness and good printability could be achieved by adjusting the chemical pretreatment and alkaline hydrogen peroxide bleaching stage,the high yield pulp（HYP）could be used to produce kinds of high added value papers,such as coated and uncoated culture paper,coach board,paper for daily use and other special paper（such as NCR,release paper and filter paper）.But HYP easily losts its whiteness via light induced discolouration for the high-containing of lingin.And the application in high grade paper of HYP is limited by this shortage.The amount of HYP in industry would be great improved if the brightness decline could be effectively controlled.The assistant agents used to inhibit the discoloration of HYP were come from plastics,rubber,textile and daily chemical industry,such as UV absorber,radical scavenger and fluorescent brightness.These agents were not suitable for papermaking industry for the poor water solubility and poor binding ability.In order to gain better affect great amount of dose was needed while the indeed affect was not as well as expect.In the thesis,couarin is choosed as FWA,and combined with other functional agents,such as UV absorber and radical scavenger.Different functional groups in one mulecule play a role,and the new product could increase the whiteness of pulp and have a goo d light stability.Hydrophilic modification and macromolecular of the product would be carried out to gain a good binding ability with paper fiber.Coumarin and its derivatives have strong flourescent property,and were widely used as fluorescent compounds,in dye lasers,in dye-sensitized solar cells,and in many other photochemical active substances.The luminescent properties of the coumarin and its derivatives depend on the appropriate substituents at the 3-,4-,and 7-positions of the coumarin moiety.When electron-donating group（-R,-OH,-RNH₂）replace at 7-position and electron withdrawing group（-CH₃,-X）at 3-OR 4-position,there is a"donor-acceptor"conjugate mode in the mulecule,the yellow compound becomes colorless,and has a strong fluorescent properties.The UV absorbtion ability,intensity of fluorescence emission would be increased by the kind of replace mode,and there is also a red-shift of absorption wavelength and emission wavelength.Firstly,basic research on preparation,characterization,application and the mechanism of yellow inhibition of the coumarin were carried out.Then,different multi-functional yellowing inhibitors were designed with coumarin derivative as a starting material.And the relation of the optical stability of paper with the yellowing inhibitor was studied.The main contents of this paper can be divided into the following sections:（1）Preparation and performance research of the coumarin fluorescent functional monomer.A series of yellowing inhibitation functional monomer were prepared.7-hydroxy-4-methyl coumarin was prepared by using the raw materials of resorcinol and ethyl acetoacetate,with toluene-p-sulfonic acid as the catalyst.7-amino-4-methylcoumarin was prepared by using the rawmaterials of 3-amino-phenol and ethyl acetoacetate,with Zn Cl₂as the catalyst.7-acrylamido-4-methyl coumarin was prepared by using the raw materials of AMC and acryloyl chloride.The products were characterized by FT-IR,UV absorption spectra,fluorescence spcetra,and UV accelerated aging experiment was carried out to study the effect on whiteness and whiteness stability of paper.The results showed that the three kinds of compounds could inhibit the light induced discoloration.AAMC showed better inhibition ability than AMC and HMC for the inducing of water soluble group.According to the results,AMC was selected as the study object of the continuous research.（2）Preparation and performance research of the coumarin fluorescent polymers based on hindered amine and UV absorber.The fluorescent compound based on coumarin with UV abosorbtion（DBAMC）was prepared by using the raw materials of AMC,cyanuric chloride and 2,4-dimethyl-benzophenone.And the fluorescent compound based on coumarin with hinder amine（TEAMC）was prepared by using the raw materials of AMC,cyanuric chloride and2,2,6,6-tetramethyl piperidine amine.PDBAMC（PTEAMC）was prepared by DBAMC（TEAMC）act with PVA,which had a good water solubility.The products were characterized by FT-IR,UV absorption spectra,fluorescence spcetra,and UV accelerated aging experiment was carried out to study the effect on whiteness and whiteness stability of paper.And the influence of intramolecular synergistic effect of multi-functional groups on the whiteness and whiteness stability was discussed.The muti-functional compounds showed better inhibiton ability than single functional compounds.And the fluorescencent propority,water solubility and photo stability were affected by the inducing of PVA,which were proved by the fact that PDBAMC and PTEAMC had better yellowing inhibition ability the DB AMC and TEAMC.（3）Preparation and performance research of multivariate coumarin copolymersThe coumarin fluoscent polymers with good water solubility and light stability was prepared by using the materials of AAMC,AM and DAC.The multi-functional coumarin fluoscent compound with good water solubility and light stability was prepared by using the materials of AAMC,DAC,AM and BME.The products were characterized by FT-IR,UV-vis spectroscopy,fluorescence spectroscopy,TGA,Zeta potential,and UV accelerated aging experiment was carried out to study the effect to whiteness and whiteness stability of paper.And the influence of high-molecular compounds of coumarin fluorescent properties was discussed.p-AAMC-AM-DAC showed better yellowing inhition ability than AAMC for the inducing of AM and DAC,but less than p-AAMC-BME-AM-DAC which had UVA and FBs groups in molecule.