Research On The Restoration Technology And Mechanism Of Curled Paper-based Photographs And Embrittlement Paper Documents

Five thousands years of history have given birth to a glorious and resplendent civilization of China.There are a huge number of the ancient or modern paper archives,such as manuscripts,books,paintings,buddhist text,files,newspapers,periodicals,magazines,currencies,photos,and so on.They are not only the records and witnesses,but also the precious wealth of the Chinese splendid culture heritage.However,the internal factors such as:historical changes,wars,natural calamities,artificial misfortunes,paper acidification and material deterioration,and external factors such as alternating upheaval of temperature and humidity,excessive light,gas erosion,mechanical abrasion,unreasonable use and so on,make some ancient paper documents be crisp,curl,mildew,powdery,mottled,multi-hole,unreadable,and lose their elasticity.The final results are deterioration and damage of these paper documents,which brings irreparable loss,and greatly reduce the conservation life,ornamental value and research value of them.Therefore,we should make full use of modern advanced materials and technologies,inherit and carry forward the previous technical methods,combine traditional technology and modern technology,and explore the new material,new technology,and new methods to achieve scientific,effective,safe and permanent preservation of the paper documents.This paper is aim to improve and perfect the traditional reinforcement technology about the huge historic photos,manuscripts and double-sided newsprints,periodicals,books.To overcome the limitations and disadvantages of the previous technologies,we would study the following five aspects:(1)Protection research on the huge-size and damaged photographic paper archives.As a special image archive,the precious huge historic photos with the photographic paper as a carrier appeal serious curl,fracture,fold and unopen diseases.A special technology with enhancing toughness,flattening,finalizing the shape and specialized harness was used to repair and preserve these huge historic photos.The flexible mechanism and physical properties of huge photos before and after repair were studied by scanning electron microscope(SEM),polarising optical microscope(POM),X-ray diffractometer(XRD),thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).The results indicate that the sphaerocrystal interface of image surface disappears,and film surface shows cellular structures.Meanwhile,a flexibilizer suppresses the contraction caused by water desorption of gelatin film to overcome the curl of huge historic photos.The results from folding strength,tensile strength,tearing strength,flexibility and chromatic aberration tests show that the mechanical strength,flexibility and chromatic aberration of repaired photo are all improved,which is in conformity with the archival protection principle.Instead of the previous preservation methods,such as curl,plastic sealing,picture frame mounting and paper parcel,a specialized "SiFang" harness was designed for the long preservation of huge historic photos.(2)Research on mounting-repairing technology of damaged paper.The multifunctional technique of "same fiber"pulp was used to repair the thin,fragile,acidulated archives,such as ancient books and manuscripts.The reinforcement,deacidification and mildew proof of paper would be simultaneously completed with modern new materials and traditional papermaking technology.The results from folding strength,tensile strength,flexibility,pH and thickness tests before and after restoration and aging show that this technology improves durability and flexibility of paper,and almost maintains pH value and thickness of paper.The results of antimould effect indicate that one sample repaired with traditional wheat starch paste appears the worst mildew,another sample without any operation appears a little mildew,while the sample repaired with our new technology appears no mildew.(3)Research on the "oil-soluble" cotton-net reinforcement technology of fragile archives with double-sided words.The "oil-soluble"cotton-net reinforcement technology was proposed to repair the decayed,damaged,paper archives with two sided character and handwriting of water resistance,such as ancient newspaper,magazine and precious book.The strengthening technology and equipment were also developed.The durability and physical properties of repaired paper samples were measured after accelerated dry-heat,damp-heat and UV-heat aging.The results show that the mechanical properties and durability of different paper samples repaired with cotton-net reinforcement and deacidification are observably improved.The SEM results reveal that paper fibers after cotton net reinforcement are very tightly arranged,which is due to that"oil-soluble"adhesive enhance the interactions between paper fibers and cotton net fibers.Meanwhile,the contact angle tests indicate that hydrophilic paper after reinforcement tends to be hydrophobic,and hydrophobic paper after reinforcement tends to be hydrophilic,which facilitates the long conservation of paper archives.(4)Research on the"water-soluble"cotton-net reinforcement technology of fragile archives with double-sided words.At the basis of previous technology,an environmental and low cost "water-soluble"cotton-net reinforcement technology is proposed.The"water-soluble"adhesive was selected to bond paper fibers and cotton net fibers,and its strengthening technology was optimized.When this technology,"oil-soluble"cotton-net technology and silk-net technology are used,the effects of restoration and UV aging on paper are comparatively studied.The results indicate that three technologies can improve the physical properties of paper,while the flimsy paper retention rate after cotton-net reinforcement and aging shows obviously higher than that after silk-net reinforcement and aging.In addition,the durability of paper after cotton-net reinforcement differs with different paper,hence it can't decide which cotton-net reinforcement technology is better.The SEM results reveal that paper fibers after cotton-net reinforcement are very tightly arranged and incrassate,because "water-soluble"adhesive enhance the interactions between paper fibers and cotton-net fibers.Meanwhile,the contact angle tests indicate that paper after cotton-net reinforcement tends to be hydrophobic,which slows down hydrophilic interaction of paper fibers,thereby slowing down the hydrolysis rate of paper fibers.(5)Research on the reinforcement technology of rotten,degraded hemp fabric and silk fabric archives.At the basis of previous cotton-net reinforcement technology,silk-net and fibre-net reinforcement technologies at ambient temperature were successfully developed to repair decayed and damaged silk banner during initial post-liberation period and bast fiber fabric during the period of Liao and Jin,respectively.The mechanical strengths of silk banner and bast fiber fabric after reinforcement are drastically improved,and the broken holes and fractures in these files are well repaired by silk-net and fibre-net.Therefore,these reinforcement technologies could repair the decayed,damaged and decomposed silk banners and bast fiber fabrics in the future.