Preparation Of Cellulose Derivatives Modified Polyacrylates Composites And Application In Paper Relics Conservation

As the first country of paper-making,paper is widely used in all fields in China.Therefore,there are astounding number of paper cultural relics in China.However,paper is easy to oxidize,hydrolyze and subjected to all kinds of erosion,such as Ultraviolet radiation,temperature,humidity,mould and insect pests.Therefore,there is great significance to strengthen the protection and repair of paper relics.Polyacrylate has been widely used in construction,leather,electronic devices and cultural relics protection,because of its good film-forming property,good adhesion,high transparency,mild reaction condition and low price.However,there also are many shortcomings of polyacrylate.In this work,on the basis of protection of paper relics,polyacrylate was modified.The details are as follows:?1?In order to improve the affinity with the paper,carboxymethyl cellulose,as cellulose derivative,was chosen to add into material.To be better to participate in the copolymerization reaction of acrylic acid kind of monomer,carboxymethyl cellulose was modified by methacrylic acid.For sake of improving the weatherability,biologically inert and hardness of the films,the silica sol was used to modify the polyacrylate,and the carboxymethyl cellulose-silicon-polyacrylate composite was prepared.The properties of the prepared CMC-Si-PA were characterized,such as stability,viscosity,surface tension,contact angle,water absorption and so on.And the instrumental analysis was done,such as Fourier Transform infrared spectroscopy?FTIR?,Thermo Gravimetric Analyzer?TG?and Transmission Electron Microscope?TEM?and so forth.The experimental results shown that the viscosity of the prepared material is between 16 m Pa·s and 24mPa·s,which indicated that the permeability of the material is good and the material protects the paper fiber in all directions.Considering,CMC-Si-3 with 6% modified Si O₂ was selected to protect the paper samples,simulation application,dry heat aging test and reversible experiment were carried out.The results showed that the prepared materials have good protective properties and reversibility.?2?Because carboxymethyl cellulose has hydrophilism,and water resistance ofpolyacrylate is poor,DFMA was selected to enhance hydrophobicity and water resistance.After studied the properties of the prepared composite material and analyzed by instrument,it was found that the swelling rate of composite material with25% DFMA?5.0% H2SO4?was 6.1% and the contact angle was 96.92°,indicating that the hydrophobicity,water resistance and acid/alkali resistance was improved greatly.The result of aging shown that prepared composites material can better protect the paper,preventing from aging.At the same time,there was slightly damage to removed the protective coating.?3?On the basis of retaining good hydrophobicity of DFMA,modified microcrystalline cellulose?MCC?and modified nano-TiO₂ were selected to enhance the affinity and UV resistance.Due to the modified nano-TiO₂ make the surface of coating to relative roughness,the contact angle reaches 104.35°.The UV-visible absorption spectra indicated that the MCC-TiO₂-F-SAE had a good absorption in the ultraviolet region?280nm-350nm?.The results of aging test shown that the composites material can slow down the aging rate of paper.Reversible results showed that ethyl acetate can dissolve and remove the protective coating,but ethyl acetate is slowly hydrolyzed to produce acidic substance which destroy paper relics.?4?For better UV resistance and longer working life,organic UV absorber UV-327 was chosen to improve performance.UV-Vis absorption spectra clarified that transmittance of emulsion was close to 0 in ultraviolet region,and transmittance was more than 80% in visible region.The results of dry heat aging test and ultraviolet aging test showed that the prepared materials could protect the paper artifacts from high temperature,low humidity and strong ultraviolet radiation.Reversible experimental results shown that the tensile strength average value of paper sample without aging after reversible experiment is 351.76N·m-1,and 98.3% of tensile strength of the blank paper sample,indicating that the damage of ethanol is poor.And ethanol is cheap and readily available,and low toxicity,which is a better solvent in reversible experiment.?5?In order to self-healing property,CaCO₃ microcapsules were applied to polyacrylate material,thereby improving the hydrophobicity and self-healingproperties of the film.CaCO₃ microcapsules can improve the film hardness,hydrophobicity and self-healing.The results shown that the film of composite material after external damage,because of the effect of the microcapsule,self healing can be achieved for the breakage.Combined with the results of dry heat aging test,the material has better protection and self-healing function,which palys long-term effective protection role of paper relics,and provides a good application basis.