Study On The Preparation Of Lignin/TiO₂ UV-shielding Material And Its Proteccting Property Of Paper Cultural Relics

Paper cultural relics are treasures of human history and civilization.Due to serious aging,many paper cultural relics have reduced their research value and historical value.Therefore,the protection of paper cultural relics substrate material has become particularly important.With the passage of time,fiber aging and brittle fracture occur in different degrees,and ultraviolet radiation is an important factor that accelerates fiber aging and paper material aging.In this thesis,alkali lignin as template,butyl titanate as the precursor of titanium,using cellulose nanofibril as inducer,combined with hydrothermal method to prepare lignin/TiO₂ UV-shielding materials,study the reaction system,different lignin and cellulose nanofibril dosage on the performance of UV-shielding materials.Then the lignin/TiO₂ UV-shielding material with styrene acrylic emulsion and hydroxypropyl methyl cellulose compound with technology,the protection of cultural relics material liquid preparation paper characterized the characteristics of the preparation methods of different protection fluid,and the rice paper painting and calligraphy to simulate protection object,to protect the paper strength,resistance to UV aging performance before and after processing are discussed in this paper,in order to offer new ideas to paper the protection of cultural relics.Firstly,Lignin/TiO₂ UV-shielding material was prepared by hydrothermal method using lignin as template and cellulose nanofibril as inducer.Nanotechnology results showed that the cellulose nanofibril has played an important role in the regulation on the particle size,the preparation of a series of lignin/TiO₂ UV-shielding materials with 10 m L butyl titanate,0.5 g alkali lignin,4 m L cellulose nanofibril under the condition of the preparation of lignin/TiO₂ UV-shielding material,with smaller particle size and good dispersion,high UV-shielding performance and lower photocatalytic performance.Then the optimal lignin/TiO₂ UV-shielding material was mixed with styrene-acrylic emulsion and hydroxypropyl methyl cellulose to prepare protective liquid for paper cultural relic materials.The effects of different preparation conditions on the state and properties of protective liquid were discussed.Results show that when the dosage of lignin/TiO₂ UV-shielding materials for 3 wt%,and hydroxypropyl methyl cellulose solution styrene acrylic emulsion quality ratio of2:1 as the optimal proportion,the emulsion stability is good,low viscosity,emulsion film after ultraviolet transmittance under 5%,emulsion membrane contact angle is 110.35°,embodies the better performance of UV-shielding and waterproof performance.Finally,on the basis of the above,the influence of protective liquid of paper material on the tensile strength,whiteness,folding resistance and water resistance of rice paper before and after coating and aging was explored.The results showed that the retention rate of optimal tensile strength was 0.5%,the retention rate of flexure was 12%,and the loss rate of whiteness was0.5%after using protective liquid to protect rice paper.Waterproof effect of solid rice paper painting and calligraphy is obvious.Combined with the analysis of electron microscopy,the paper material sealed by protective liquid effectively prevented the aging of the fiber,and the dense anti-ultraviolet and anti-oxidation coating increased the bonding strength between the fibers,which played well protective effect on the paper cultural relics.Comparing the appearance and texture of paper pattern before and after aging,the nameless change is obvious,which met paper material protection standards.