Vinegar Syndrome Eradication in Film Conservation: A Novel Silica-nano-CaCO3/Ethylcellulose/N-butanol System

Abstract

Photosensitive images serve as invaluable cultural heritage, holding an irreplaceable position in the documentation of human history, the display and dissemination of culture and art, as well as in the realms of development and exploration. However, a large amount of triacetate film degrades and suffers from the damage of "vinegar syndrome." Research has proven that environmental control alone cannot effectively suppress the occurrence of "vinegar syndrome," hence the need for deacidification protection of the photosensitive images (triacetate film) itself. This paper selects nanoscale calcium carbonate as the deacidification material and uses sodium silicate as the silicon source to coat and modify it by a counter-current method, preparing silica-coated nanoscale calcium carbonate particles to improve their dispersibility and acid resistance. The modified calcium carbonate is then combined with ethyl cellulose/n-butanol solution to form a deacidification and reinforcement composite material, which is applied to the film affected by "vinegar syndrome" by brushing. The pH of the coated film is increased from 4 to above 6.5, and contact angle testing indicates that the film surface becomes hydrophobic. After aging different treated films, thermal gravimetric analysis and XRD analysis reveal that the coated films exhibit better thermal and molecular stability; the tensile strength is enhanced, with stress-strain increasing from 27.35 MPa and 4.32% to 86.43 MPa and 5.53%, and remaining within a safe range after aging. The deacidification and reinforcement composite material also reduces the negative impact of increased film surface roughness and decreased optical performance caused by scratches and other defects on image clarity. Comparative experiments demonstrate that this deacidification and reinforcement material has a certain effect and research value in the treatment of "vinegar syndrome."