Nano meets the sheet: adhesive-free application of nanocellulosic suspensions in paper conservation

L Völkel,K Ahn,W Gindl-Altmutter,U Hähner,A Potthast

doi:10.1186/s40494-017-0134-5

Abstract

Historical papers are often locally damaged by exogenous influences and/or have endogenously degraded paper areas. The stabilization of such papers is very important because further use of the object can cause additional damage. Different types of nanocellulose are interesting as a novel stabilizing materials for paper due to their close structural relation to the paper matrix. Therefore, the present study investigated whether the treatment of historical papers with nanocellulose suspensions is a novel method for paper stabilization. Two different types of nanocelluloses, bacterial cellulose and a mechanically nanofibrillated cellulose based on wood pulp, were tested with regard to their performance in stabilizing fragile papers. Concerning material handling and application in conservation steps, different ways to modify the suspensions were tested. The resulting suspensions were applied to historical papers from several centuries with different extents of damage. The paper-nanocellulose composites were characterized with regard to their optical and microscopic integrity and by physical and chemical analyses. The treatment of mechanical damage and the consolidation of weakened paper areas could be realized by the application of a nanocellulose suspension without an additional adhesive. The results of the treatment depend on the type of nanocellulose, on the paper material, on processing and application techniques. The paper discusses the applicability and stability of the differently prepared nanocellulose suspensions, also with regard to their mode of application and long-term performance. Advantages and limitations are addressed in detail.Graphical abstractBacterial nanocellulose and nano-fibrillated cellulose from pulp can be used to consolidate damaged historic papers without the application of additional adhesives

Highlights

Mechanical damage in form of cracks, cuts, fractures, losses, creases, and deformations very often occur to documents in archives, libraries, and museums
Bacterial nanocellulose and nanofibrillated cellulose (NFC) were applied on different paper samples that represent the types of papers to be treated in the future with specific paper properties to be considered, such as the wettability of papers, which is crucial for treatment with nanocellulose suspensions due to the high water content
The results show that the application plays an important role for the strength properties, because different amounts of suspension and fibre material were applied (BNC 0.1, 1, 0.25 mm; Fig. 7), which affected the paper strength

Summary

Introduction

Mechanical damage in form of cracks, cuts, fractures, losses, creases, and deformations very often occur to documents in archives, libraries, and museums. Different types of damage are caused by local and/or external forces acting on single items. Damage is most often present around the edges. Sheet borders are exposed to atmospheric influences that could have a negative effect on the strength properties close to the edge of papers. Völkel et al Herit Sci (2017) 5:23 papers should be preserved in case of further mechanical stress. This should allow for lower risk when handling papers (Fig. 1)

Methods

Results

Conclusion