Nanomaterials for Combined Stabilisation and Deacidification of Cellulosic Materials—The Case of Iron-Tannate Dyed Cotton

Abstract

The conservation of textiles is a challenge due to the often fast degradation that results from the acidity combined with a complex structure that requires remediation actions to be conducted at several length scales. Nanomaterials have lately been used for various purposes in the conservation of cultural heritage. The advantage with these materials is their high efficiency combined with a great control. Here, we provide an overview of the latest developments in terms of nanomaterials-based alternatives, namely inorganic nanoparticles and nanocellulose, to conventional methods for the strengthening and deacidification of cellulose-based materials. Then, using the case of iron-tannate dyed cotton, we show that conservation can only be addressed if the mechanical strengthening is preceded by a deacidification step. We used CaCO3 nanoparticles to neutralize the acidity, while the stabilisation was addressed by a combination of nanocellulose, and silica nanoparticles, to truly tackle the complexity of the hierarchical nature of cotton textiles. Silica nanoparticles enabled strengthening at the fibre scale by covering the fibre surface, while the nanocellulose acted at bigger length scales. The evaluation of the applied treatments, before and after an accelerated ageing, was assessed by tensile testing, the fibre structure by SEM and the apparent colour changes by colourimetric measurements.

Hybrid fibroin-nanocellulose composites for the consolidation of aged and historical silk

“…Hybrid materials [18] and biopolymers constitute a promising alternative to traditional approaches; in particular, the focus is on environmentally friendly materials that can be used to formulate consolidants [19] and composite systems [20] with desirable properties. Among them, fibroin and cellulose are optimal candidates: the first has, in principle, maximum physico-chemical compatibility with silk fibers, while the second, in particular in the form of cellulose nanofibrils (CNFs) and nanocrystals (CNC), exhibits ideal mechanical properties [21][22][23].…”

Recent Developments in the Application of Inorganic Nanomaterials and Nanosystems for the Protection of Cultural Heritage Organic Artifacts

“…Similar to the paper and wood applications, the deacidification of leather or dyed textiles can be achieved using similar compounds. The literature reviewed presented some examples on this topic, suggesting the application of calcium hydroxide or carbonate for deacidification purposes [73,79]. Their action on such artifacts is similar with the previously presented application, and particular attention is necessary for the interaction of the deacidification agent-collagen in the case of leather artifacts.…”

Advanced Materials in Cultural Heritage Conservation

“…Mixtures of polyelectrolyte-treated silica nanoparticles (SNP) [ 88 ] and cellulose nanofibrils (CNFs) have been used to treat the backside canvases of classic and modern paintings [ 89 , 90 ] or to address the conservation of iron-tannate dyed cotton [ 91 ]. The main strengthening effect induced by the presence of silica particles is an increase in the fiber stiffness, most likely owing to dense packing of the particles at the fiber surface, while CNFs film at the treated surface, allowing for increased ductility of the canvas.…”