Research On The Post-post Restoration Of The Bottom Painting Of Zaojing In Dayu Temple, Hancheng

As a carrier for recording characters,colors and shapes for hundreds of years or even thousands of years,paper relics have made great contributions to the study of colors,pigments,and the value and history of beauty.Because of the characteristics of frangibility,it is not easy to keep it so far,and it is not necessary to mention various kinds of information contained in the paper.In the process of preservation of paper relics,cellulose is very vulnerable to light,acidic environment,oxygen and impurity molecules in the air,which causes yellowing,embrittlement and degradation.Finally,the paper relics and the recorded information are ambiguous,even very likely to be broken and seriously reduced in strength and powdered.According to the peeling of Hancheng Dayumiao algae well painting due to paper acidification and degradation of adhesive,the adhesive suitable for paper reattachment is developed in this paper.Because the paper itself is relatively thin and fragile,so the adhesive for paper relic is more strict,and this paper develops a kind of good cohesional strength,good water resistance and aging resistance adhesive,mainly from the following five points of view:(1)This paper briefly introduces the adhesives used in cultural relics affixing in recent years.The adhesives are divided into inorganic and organic adhesives,which contain phosphate and silicates adhesives,while organic adhesives include epoxy resin,polyurethane,acrylate resin and so on.After consulting the literatures,it is found that each adhesive,whether inorganic or organic,has its own advantages,but it also has some disadvantages which cannot be avoided because of the structure of the substance itself.For example:inorganic adhesive has excellent air permeability,water permeability,but generally darker color,heavier,while organic adhesives’cohesional strength is obvious,often with colorless transparent state,but aging resistance,water resistance is poor.Therefore,compound adhesive is more and more popular in the field of heritage restoration.(2)Referring to the relevant literature and the principles of heritage protection,the main bonding component was determined to be waterborne polyurethane.However,due to its poor water resistance and aging resistance,waterborne fluorides with good weatherability were selected to modify waterborne polyurethane.In the development of adhesive,cohesional strength,contact angle,micro-morphology and infrared spectrum data were used to optimize waterborne polyurethane and water-based fluorine,and finally the properties of the adhesive were characterized.The adhesive has excellent heat resistance,mechanical and optical properties.(3)The weatherability and aging resistance of adhesive were evaluated.The weather resistance of the adhesive was analyzed by soaking the adhesive in water and acid,alkali solution of the same concentration,and the weight change of the film during immersion was recorded.Thiough the comparison of the quality change rate of the films under three conditions,we can easily determine the difference of weatherability between water and acid,alkali base.The adhesive was aged by dry-heat,wet-heat,ultraviolet and freeze-thaw.The mechanical properties of the adhesive after aging were analyzed in more details by testing the bonding strength,micro-morphology,chromatic aberration and infrared spectrum of the adhesive during the aging period.Macroscopical performance and changes in molecular structure.The bond strength data show the result of increasing and then decreasing after aging.The change of micro-morphology is not obvious,and the surface of the film is still smooth.The chromatic aberration showed a slight change,but all of them were less than 3,and there was no significant change in the original state of the cultural relics.It can be concluded from the infrared spectra that the molecular structure has not changed,and the intensity of the characteristic absorption peak of the adhesive has just weakened under ultraviolet aging,but it has not disappeared or produced new absorption peak.(4)A full understanding of the sample fragments collected from the Dayu Temple in Hancheng:first,through the analysis of paper fibers,fillers,pigments and adhesive,we can make a full understanding of the body of cultural relics,in order to prepare for the selection and development of adhesive in advance.At the same time,in the whole analysis process,not only the specific composition of ontology can be determined,but also the ability of data processing and reasoning and analysis can be improved,and it can be fully prepared for the simulation replication of algae well painting in the later stage.(5)In the process of application,the adhesive has little effect on the original appearance of cultural relics,which does not violate the principle of cultural relics protection,and the performance of the repaired ones in tracking and testing also maintains certain stability.At the same time,the effect of the simulation and replication of the algal well picture is shown,not only is the picture infinitely close to the original picture,but also is beneficial to the preservation of the algae well picture.