Preparation And Properties Of Nanoparticle Composite Coumarin Fluorescent Polymer Emulsion

High yield pulp(HYP)retains more than 20%of lignin,causing photo-induced yellowing under the interference of the external environment,which obstructs the application and popularization of HYP.Fluorescent brightener agent(FBA)is one of the important additives to suppress the yellowing of HYP paper.Of them,coumarin FBA not only has high fluorescence quantum yield and good light stability,but also has strong blue fluorescence in the visible light range,which can effectively suppress the yellowing of paper.However,it has poor water solubility and weak binding ability with paper.In response to these defects,coumarin FBA was made into a fluorescent polymer emulsion,and introduced inorganic nanoparticle silica and zinc oxide into it,and coated it on HYP paper,in this paper.The yellow effect and other paper properties have been greatly improved compared to the coumarin matrix.The specific research contents are as follows.In this paper,six fluorescent polymer emulsions were prepared.Using cyanuric chloride as the bridging group,fluorescent monomers were prepared by introducing taurine and N-methylol acrylamide into coumarin fluorescent brightener agent matrix.Then it is emulsion polymerized with styrene,N-methylolacrylamide and modified nanoparticles to prepare two nanoparticle composite anionic coumarin fluorescent emulsions(SiO2-CFBs and ZnO-CFBs);A new type of fluorescent monomer was synthesized by introducing a double bond on the coumarin matrix,and two nonionic nanocomposite coumarins fluorescent polymer emulsions(SiO2-CFBE and ZnO-CFBE)were prepared by emulsion polymerization of the fluorescent monomer with acrylamide,styrene and modified nanoparticles.A cationic monomer was introduced into SiO2-CFBE and ZnO-CFBE to prepare two nanoparticle composite cationic coumarin fluorescent polymer emulsions(SiO2-CFBEM and ZnO-CFBEM).Various characterization techniques were used to reveal the particle size,stability,optical properties,thermal stability and the sizing performance on HYP paper surface of these emulsions,systematically explored their yellowing inhibition effect and physical properties on HYP paper through coating experiments.The characterization results show that the prepared six emulsions have uniform particle size distribution and good stability.The results of ultraviolet spectrum and fluorescence spectrum reveal that the prepared emulsion has good optical properties.The stability analysis results indicate that the emulsion is more stable after the introduction of nanoparticles.SEM images demonstrate that after applying the emulsion to HYP paper,it can form a film on the surface of the paper very well,making the paper surface smoother.The coating experiment results show that the emulsion SiO2-CFBs and ZnO-CFBs improved the tensile strength of paper by 2.43 kN/m and 2.02 kN/m respectively compared with the blank,the contact angle is increased by 8.23° and 10.27°,and the whiteness of the two papers is increased by 2.93%(ISO)and 2.84%(ISO)respectively.After UV aging,the PC values are 1.54 and 1.415 respectively.SiO2-CFBE and ZnO-CFBE improved the tensile strength of paper by 1.31 kN/m and 1.42 kN/m respectively,and the contact angles is increased by 26.270 and 28.3°,and the whiteness of the two papers is increased by 0.88%(ISO)and 1.7%(ISO)higher than the blank,the PC values after UV aging are 2.18 and 1.81 respectively.SiO2-CFBEM and ZnO-CFBEM improved the tensile strength of paper by 2.73 kN/m and 2.31 kN/m respectively compared with the blank,the contact angle is increased by 29.86° and 31.16°,and the whiteness of the two papers is increased by 2.68%(ISO)and 1.7%(ISO),and the PC values of the paper after aging are 2.18 and 2.06,respectively.The six kinds of fluorescent polymer emulsions have good whitening,yellowing resistance and strength enhancement effects on paper,and can be used as a multifunctional paper surface sizing agent with good application prospects.And the anionic nano-zinc oxide composite coumarin fluorescent emulsion(ZnO-CFBs)has a better effect of inhibiting yellowing.Nano silica composite cationic fluorescent polymer emulsion(SiO2-CFBEM)shows excellent performance in improving the tensile strength of paper.