Deacidification And Reinforcement Of Paper Cultural Relics Based On Modified Cellulose Composite Nano Alkaline Metal Compounds

As a carrier of the writing and printing,paper plays an important role for recording history and carrying written information and extending cultural essence.However,the paper can be irreversiblly damaged due to the factors such as deterioration of its own materials,drastic changes of temperature and humidity,photocatalytic degradation,and microbial erosion,resulting in the loss of its historical and cultural values.Although many domestic and foreign research institutes have already carried out the protection and restoration for paper cultural relics,they have not yet obtained ideal and effective protection strategies.The protection and restoration of paper artifacts is still a very valuable issue.This paper focused on three common diseases of paper cultural relics:the acidification of decayed paper,lead white darkening in calligraphy and painting,and fungi growth in paper.For governing these diseases,a method based on modified cellulose-stabilized nano-metal compound dispersions was proposed.The effectiveness and the effect of the dispersions on the structure and properties of the paper was systematacially investigated.The mechanism of the cellulose-stabilized nano-metal compound dispersion in the restoration of paper artifacts was also studied.First,the HPMC-stabilized Ca(OH)2-NPs alcohol dispersion(H-C dispersion)was prepared by using hydroxypropyl methyl cellulose(HPMC)as a stabilizer of nano-calcium hydroxide.The H-C dispersion was characterized by X-ray diffraction,Laser Particle Analyzer and UV-vis spectrophotometer.The effect of HPMC on the stability of Ca(OH)2-NPs alcohol dispersion was investigated.The SEM,pH meter and Unitoron Universal Tester and the Folding Resistance tester were used to characterize the deacidification and reinforcement of the paper by the H-C dispersion.The results showed that HPMC can stabilize Ca(OH)2-NPs alcohol aqueous dispersion for a long time;it wrap Ca(OH)2-NPs to increase uniform distribution on the treated paper and reduce the adverse effect by decrease the contact of Ca(OH)2-NPs and paper The H-C dispersion enhances the mechanical properties of the paper and increases the pH of the paper,and provides a certain amount of alkaline storage for the treated paper.Second,HPMC was used as a nano-calcium peroxide stabilizer and a paper reinforcing agent to prepare HPMC-stabilized CaO2-NPs dispersion(reversing agent of darken lead white)for the treatment of lead white darkening in calligraphy and painting.The reversing agent was characterized by a UV-visible spectrophotometer for the to study the effect of HPMC on the stability of the CaO2-NPs dispersion.The SEM,pH meter,Unitoron Universal Tester and Folding Resistance tester were used to examine the capacity of cleaning and deacidification.The results showed that HPMC as a stabilizing agent could not only stably disperse CaO2-NPs,but also strengthen the paper artifacts.CaO2-NPs can not only effectively remove the black lead on the surface of the cultural relics,but also neutralize the acidic substances in the artifacts.And,the reversing agent did not affect the design and color of the artifacts themselves.The mechanism of the the removal of the lead white darkening was proposed as follow.The reaction of calcium peroxide and water produce the active substance hydroxyl radical,which oxidize lead sulfide,the black material,to generate the white material lead sulfate.Third,QC-stabilized nano-ZnO dispersion(Z-Q dispersion)was prepared by using quaternized cellulose(QC)as a stabilizer of nano-zinc oxide for the antibacterial and deacidification of paper.The Z-Q dispersion was characterized by UV-vis spectrophotometer to examine the effect of QC on the stability of ZnO-NPs dispersion.The antibacterial properties of QC and ZnO on paper were investigated by using a camera and SEM.The pH meter and Unitoron Universal Tester and the Folding Resistance tester were used to examine the effect of Z-Q dispersion on the deacidification of paper.The results showed that the QC,a kind ofsoluble cellulose derivative,structurally similar to the cellulose,could be evenly filled in the paper fiberto improve the mechanical properties of the treated paper.Both QC and ZnO could inhibit the growth of fungi;QC could stabilize the nano ZnO dispersion for a long time,which uniformly dispersed the nano ZnO on the paperto evenly implement the bacteriostasis and deacidification function on the paper,and effectively decrease the damage of the mold to the cultural relics.The Z-Q dispersion can simultaneously achieve the function of antibacterial,deacidification and reinforcement for paper artifacts.Common diseases in the process of paper cultural relic restoration:the acidification of decayed paper,lead white darkening in calligraphy and painting,and fungi growth in paper,in this dissertation,a multi-functional restoration system was constructed with different modified cellulose and nano-metal compounds as raw materials,and successfully applied to the restoration of paper cultural relics.These studies are expected to provide theoretical and technical support in the field of paper repair based on modified fibers and nanomaterials.