One-Step Reinforcement and Deacidification of Paper Documents: Application of Lewis Base—Chitosan Nanoparticle Coatings and Analytical Characterization

Fangnan Zhao,Chun Yang,Yuhu Li,Xiaolian Chao,Zhihui Jia,Huiping Xing

doi:10.3390/coatings10121226

Abstract

To delay acidification and deterioration during natural aging, deacidification and reinforcement of paper manuscripts have been the most important technologies to prolong the life of objects. Herein, a novel approach for the conservation of paper manuscripts is proposed using chitosan nanoparticles as Lewis base that leads to both deacidification and strengthening of paper in one-step. Chitosan nanoparticles were prepared through physical ball grinding method and characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer (LPSA), Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). To evaluate the resistance of chitosan nanoparticle coating, the mechanical properties of paper after artificial aging were evaluated using dry heat and hygrothermal accelerated aging methods. The SEM, EDX, and X-ray Photoelectron Spectroscopy (XPS) were used to analyze the interaction mechanism between chitosan and Shuxuan paper. The results show that the coated paper had superior durability with respect to pH, tensile strength, and folding endurance. There was a presence of protonated amines in the form of ammonium salts due to ionic bindings with free H+ in the acidified paper, and the remaining –NH2 could be used as a base reserve. Finally, the resulting coated papers displayed good antibacterial properties.

Highlights

Besides several industrial applications, cellulose-based materials, such as paper and canvas, which are primarily composed of cellulose, provide the most common types of support for works of art.Cellulose in historical manuscripts is subjected to several decay processes that may lead to irreversible degradation and ultimate loss of valuable information [1,2]
Chitosan nanoparticles areare employed forfor thethe one-step reinforcement andand deacidification of of Chitosan nanoparticles employed one-step reinforcement deacidification paper documents
Chitosan nanoparticles are prepared via the physical ball grinding method and paper documents

Summary

Introduction

Cellulose-based materials, such as paper and canvas, which are primarily composed of cellulose, provide the most common types of support for works of art.Cellulose in historical manuscripts is subjected to several decay processes that may lead to irreversible degradation and ultimate loss of valuable information [1,2]. Cellulose is a linear polymer consisting of several hundred to over ten thousand d-glucose units linked to each other by a β-(1,4)-glycosidic bond. The degree of polymerization (DP) of native cellulose can vary between 7000 and 15,000 depending on the plant species [3]. The hydrolysis of β-(1,4)-glycosidic bonds of cellulose linear chains is catalyzed by acidity and is the main cause of cellulose-based material degradation, reducing the mechanical properties of cellulose-based materials [4]. The hydrolysis reaction is affected by multiple factors such as pH, temperature, moisture content, and degree of crystallinity, and can be described using a three-step mechanism [5,6], resulting in a self-accelerating reaction [7,8]

Methods

Results

Conclusion