Transglutaminase-mediated restoration of historic silk and its ageing resistance

Introduction: Transglutaminase-mediated polymerization, unlike the traditional restoration methods based on the application of synthetic polymers, has proved to be a potential strategy in the restoration of historic silk. In the present study, the treatment process has been adapted to satisfy the needs of consolidating historic silk fabrics in various cases. Artificially aged (dry thermal ageing) silk samples were restored using this method. The effects of the reaction on silk fibers were investigated by tensile tests, colour difference tests, scanning electron microscopy and FT-IR. The ageing resistance of the restored samples was evaluated. Results: The results showed that tensile strength, elongation rate at breakage and micro morphology of the silk samples were remarkably improved without significant colour difference after restoration. FT-IR spectroscopy confirmed the existence of transglutaminase-induced biopolymers in the restored silk samples and demonstrated that the transglutaminase-mediated restoration did not change the basic structure of silk protein. The ageing resistance of the restored samples evaluated using standard methods ensured that the treatment would not introduce any long term problems. The method was then applied to genuine historic silk fabrics and achieved the desired results. Conclusions: From the results of this study, the effectiveness of transglutaminase-mediated polymerisation to restore historic silk was demonstrated.