Study on microbubble of cellulose acetate microfilm of the Republic of China (AD 1912–1949) collected in the Second Historical Archives of China

Abstract

The white spots known as microbubbles that are formed in cellulose acetate film, significantly affects the texture of the image. However, the formation of microbubbles and their corresponding microstructure are poorly understood. In this paper, cellulose acetate microfilm from the Republic of China (AD 1912-1949) collected in the Second Historical Archives of China was chosen as a prototype to investigate the causes of microbubble disease for the first time. A comparative study was conducted between the film samples with and without microbubbles. Herein, the microstructural analyses including optical and SEM microscopy were conducted. The crystals in the microbubbles proved to be triphenyl phosphate as identified by NMR spectroscopy and SEM-EDX. Comparative properties of the film substrate with and without microbubbles were measured by TG, XRD and FT-IR spectroscopy. The results show that formation of microbubbles was generally accompanied with the vinegar syndrome and was produced between the protective and emulsion layers with the different types of shapes along the closed structure (the diameter of ~ 0.1-2 mm). The formed microbubble was filled with plasticizer. Based on the above-mentioned results, the possible formation process of microbubble was proposed in the present study. The results can provide support for the cause of microbubbles and basis for the conservation of photographic films.

Plasticiser loss in heritage collections: its prevalence, cause, effect, and methods for analysis

“…More recently, a study of twentieth century Chinese CA microfilm linked deacetylation of the film substrate to the migration of TPP and the formation of microbubbles. The study also found increased hydrophilicity in areas of the film affected by microbubble formation [85]. In other studies, TPP's hydrolysis products of phenol and diphenyl phosphate have been detected, suggesting plasticiser and migration of by-products can also occur [4,86].…”

Discoloration of Historical Plastic Objects: New Insight into the Degradation of β-Naphthol Pigment Lakes

“…Plastics in collections are challenging to preserve, as they tend to degrade faster than other materials found in artworks [9][10][11][12][13][14][15][16][17]. Synthetic organic/inorganic pigments also have stability issues [18][19][20][21][22][23][24][25] and their alteration in modern polymeric paints continues to be a subject of ongoing research in art conservation [26][27][28][29][30][31].…”

The Treatment of Microbubble Disease of 20th Century Cellulose Acetate Microfilm: Application of Ethyecellulose and Microrepair Method 

“…Recently, we have studied the causes of microbubble diseases of cellulose acetate micro lm collected in the Second Historical Archives of China [15]. The results showed that microbubble disease is accompanied by the production of vinegar syndrome.…”