Nanocollagen for Historical Leather Conservation: A Case Study on Three Islamic Bookbindings

Historical book artefacts are highly susceptible to degradation processes, particularly when characterised by leather bindings, whose deterioration progressively compromises the cohesion and structural integrity of the artefact. Among the consolidating agents commonly employed for their conservation, Klucel G is one of the most widely used materials; however, its long-term stability and compatibility with degraded leather substrates are still discussed. Consequently, alternative materials have been investigated for the conservation of historical leather, among which Nanocollagen has emerged as a particularly promising solution. The present study evaluates the performance of Nanocollagen compared to that exhibited by the conventional Klucel G-based treatments. Three Islamic bookbindings preserved at the Library of the University of Naples “L’Orientale” were characterised using a multi-analytical approach including optical microscopy, pH measurements, qualitative chemical assay, FTIR and Raman spectroscopy, SEM-EDS, Spectrocolorimetry, and Mechanical tests. Laboratory mock-up samples were prepared to assess the effectiveness of the treatments, and subsequently applied to the original samples collected on the historical bindings. The results demonstrated that Nanocollagen preserves the surface morphology of leather, induces negligible chromatic variations, and improves the flexibility of degraded samples when compared to the conventional Klucel G conservation treatments. The best result is observed when Nanocollagen is applied to samples exhibiting moderate damage—specifically, a structural order-to-disorder transition of the protein material (essentially, an early-stage rather than advanced case of “red rot”).