The improvement of aging time on adhesive performance of wheat starch paste for restoration of Chinese ancient books

Abstract

Abstract In the restoration of Chinese ancient books, wheat starch paste is used as a paper adhesive, and its performance directly affects the quality of the restoration work. Allowing the starch slurry to stand for several days until it becomes slightly acidic can enhance the adhesive performance of the paste. However, the entire process relies on the manual experience of craftsmen. The study reproduces the process of making wheat starch paste for the restoration of traditional ancient books and investigates the effects of aging time on the apparent viscosity, rheological properties, and adhesive performance of the paste. The results indicate that the aging process has minimal impact on the apparent viscosity and rheological properties of starch paste. However, it significantly enhances adhesive performance, with optimal results observed after aging for approximately three days. This is attributed to the reduction in residual protein content in starch and a significant improvement in starch gelatinization capability. Infrared spectroscopy and XRD test results reveal that there are no significant changes in the molecular and crystalline structures of starch during the aging process. The acidic environment produced by starch fermentation promotes protein hydrolysis, emerging as the primary reason for the improved adhesive performance of the paste.