Study On Deacidification Repair Of Paper Cultural Relics Based On Ultrasonic Atomization

Cultural relics in paper are an important record carrier of human history and cultural heritage.It is kind of historical relics collection and is also widely used for academic purposes.However,they are suffering from aging and deterioration spurred by acidification,oxidation and other factors.After nearly a hundred years of storage,the acidification of some documents has reached a very serious level,and some have been completely destroyed.Domestic and foreign scholars have conducted in-depth research on the aging mechanism of paper,and believe that the main cause of paper aging is the acid degradation of paper.However,existing de-acidification and reinforcement reagents and methods have some defects,and they cannot be promoted and applied due to problems such as low speed,high equipment requirements,and harm of the appearance of paper.Based on the in-depth analysis of paper damage mechanism and existing protection methods,combined with the preservation status and repair requirements of paper cultural relics,in the paper,a gas-liquid interaction method-ultrasonic atomization method was utilized.The ultrasonic atomizer can make the de-acidification agent into micron-droplets,so that the paper absorbs the de-acidification agent slowly and fully,the paper is not wetted and deformed at the end.The absorption effect is uniform,and the atomization effect is easily controlled.There is no strict equipment requirements and it is good for mass de-acidification.After a large number of trials in the early stage,this paper used sodium carbonate to de-acidify the paper by ultrasonic atomization.At the same time,in order to make the paper life longer,the latex composites are used to reinforce the paper,which might improve the mechanical strength of the paper and stay stabilized after ageing.The single-paper de-acidification treatment was carried out by ultrasonic atomization of sodium carbonate.This paper mainly studied the effects of de-acidification agent concentration,ultrasonic atomization rate and ultrasonic power on the de-acidification effect of the paper,and the changes of the internal structure of the paper before and after aging.The results show that when the de-acidification agent concentration is 0.4mol/L,the ultrasonic atomization rate is 0.82mL/min,and the de-acidification agent sodium carbonate dosage is20mmol,the pH of the paper after de-acidification is 8.44,and after aging is 8.02,both of them are in the range of 7 to 8.5,which is neutral to weakly alkaline.The chromatic aberration is within 0.5,the color change is slight,and the human eye is basically imperceptible.After de-acidification,the paper breaking length is 1.24km,the retention rate after artificial aging is 89.43%,the tear index is 2.71mN·m²·g^-1,and the retention rate after artificial aging is 79.34%.The paper breaking length and tear index changed slightly,and the performance of the paper after artificial aging is also relatively stable.The alkali storage was0.25 mol/kg.There is basically no deformation such as unevenness,wrinkles and curls on the macroscopic appearance of the paper.The treated paper even maintained the original shape.Ultrasonic atomization of sodium carbonate and latex composites was used to de-acidify and strengthen the single paper.The de-acidification and anti-aging properties of the de-acidification agent and latex composites on the paper were investigated.The results showed that when the de-acidification agent and latex were used at the ratio of 5:3,the paper has the best de-acidification enhancement effect.The paper pH is 8.66,the breaking length is1.46km,and the tear index is 3.37mN·m²·g^-1.The paper after de-acidification and strengthening after artificial aging has more stable performance and obvious anti-aging effect.Macroscopically,the latex composite has little effect on the color of the paper,and the ink and writing are not diffused or smudged.Microscopically,it can be clearly observed according to the SEM image.The latex composite is microsphere type,and mainly adheres to the fiber surface by spherical dispersion.The transfer of de-acidification agent in multi-layer paper based on ultrasonic atomization method and the effect of de-acidification are preliminarily explored.The results show that for each paper and the whole paper,the change rule is that from upper layer to lower layer,the paper moisture content and pH gradually decrease,and the paper absorption rate decreases with time.After the acid is nearly removed,the paper has a small change in brightness and chromatic aberration from the upper layer to the lower layer.The chromatic aberration of the paper is 1.5,which can hardly be detected by naked eyes;the paper braking length and the tear index increases slowly from top to bottom,but the amount of change is slight.