| As an ancient civilization,China has a multitude of paper artifacts.These paper artifacts,as a special carrier of history and culture of the Chinese nation,have witnessed the 5,000-year historical changes of the Chinese civilization and recorded a large amount of culture,science and technology,political,economic and other information.It is an important historical and cultural heritage with extremely high research and preservation value.However,paper artifacts became brittle,fragile and moldy due to various factors,which seriously affects the preservation time of paper artifacts.So it is urgent to protect and strengthen them.As natural polymers,cellulose nanofibrils have the same structure with paper,have good physical and chemical properties,and have a strong binding force with paper.Based on this,this paper studies the reinforcement of paper with non-aqueous reinforcing reagents based on nanocellulose fibrils and the effect of nanocellulose fibrils as adhesives in paper's mounting process.Looking forward to providing new methods for the conservation of paper cultural relics.The main contents of the thesis include the following aspects:1.Study on the reinforcement effect of cellulose nanofibrils on paperThe spray-dried cellulose nanofibrils were milled with a high energy mill.The physical and chemical properties of the ball milled cellulose nanofibrils were characterized by SEM,LPSA,TG,FTIR,XRD and other analysis methods.The results show that the particle size of cellulose nanofibrils decreased after ball milling but its molecular structure has not changed.The ball milled nanocellulose dispersed with isopropanol was applied to treat paper samples.The paper samples were analyzed by tensile tester,folding tester,softness meter,spectrophotometer,pH Meter,SEM,FTIR,XRD,etc.The results show that the mechanical strength of samples treated in cellulose nanofibrils has increased significantly without changing the color and softness.But the durability of paper samples was decreased due to the poor thermal stability of cellulose nanofibrils.2.Study on the reinforcement effect of cellulose nanofibrils combined with barium phosphotungstate on paperThe barium phosphotungate was prepared by mixing saturated barium hydroxide methanol solution with phosphotungstic acid ethanol solution.The properties of barium phosphotungstate and barium phosphotungstate nanocellulose fibril composites were characterized by SEM,XRD,XPS and TG.The paper samples were treated with the dispersion of cellulose nanofibrils combined with barium phosphotungate.The samples' mechanical strength was analyzed by tensile tester and folding tester,and its microscopic properties were characterized by SEM,FTIR and XRD.The results show that the barium phosphotungstate particles are embedded in the CNF film.The samples strength is improved significantly compared with the samples treated only with CNF due to the interaction between the particles and the CNF film and the durability of samples are increased.The color difference before and after aging is decrease too.3.Study on deacidification and reinforcement effect of cellulose nanofibrils combined wtih MgO nanoparticles on acid paperThe dispersion of cellulose nanofibrils combined with MgO nanoparticles was applied to treat acid paper samples,and the samples were subjected to the aging test.The samples' properties were characterized by paper tensile tester,folding tester,pH meter,spectrophotometer,SEM and FTIR.The results show that the nano-magnesium oxide is wrapped by the cellulose nanofibrils film and adheres tightly to the paper fibers through electrostatic action,which significantly improves the mechanical properties of acid paper samples.At the same time,nano-magnesium oxide can increase the pH of acidified paper.The mechanical strength retention rate after treatment is greatly improved,and the color difference is reduced.It indicates that the addition of nano-magnesium oxide can improve the durability of acidified paper and improve the discoloration phenomenon of acidified paper.4.Preliminary study on cellulose nanofibrils as adhesives for paper mountingThe properties of viscosity,adhesive strength and the effects on paper's mechanical properties of cellulose nanofibrils,wheat starch paste and carboxymethyl cellulose were analyzed with rheometer,universal material testing machine,softness tester,folding tester,etc.In addition,the anti-mildew and reversibility experiments of above adhesives were performed.The results show that the cellulose nanofibrils does not change the softness of the paper,and has good stability,proper viscosity,mildew resistance and reversibility.Cellulose nanofibrils combined with wheat starch has excellent stability,film-forming properties,low viscosity,and aging resistance. |
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