Anne-Laurence DUPONT

Degradation

1/ When paper gets a sun burn and X-rays…. at SYNCHROTRON SOLEIL

Among the various analytical and imaging techniques that can be used to characterize and assess the state of conservation of heritage objects, those using X-rays occupy a leading position, especially when produced by synchrotron radiation (SR-X). The intense and stable SR beam, tunable over a wide range of energies, provides spectral images down to a few centimetres in view field, with spatial resolutions down to a few tens of nanometres. This allows to analyse crystalline structures, chemical compositions and environments of materials with a high detection sensitivity. The downside is the risk of modifying the chemistry of the materials. The risk is however still poorly characterized, yet this is a crucial issue in SR-X ray studies of ancient and heritage materials to which SOLEIL’s PUMA line is dedicated. The work focused on the short- and long-term effects of exposing paper to SR-X rays.

The research team consists of researchers from Centre de recherche sur la conservation des collections (CRC-MNHN-CNRS 3224), laboratoire IPANEMA (CNRS- MiC-UVSQ USR 3461) and the beamline PUMA (Synchrotron SOLEIL)

Credits

Biomacromolecules 2020, 21, 2795−2807. ToC graphic

Post-doc A Gimat

Financial support FSP (CELL-X, CELL-X II)

Publications 

Short- and Long-Term Effects of X‑ray Synchrotron Radiation on Cotton Paper, 

When paper gets a sun burn at SOLEIL, 

Short- and long-term effect of radiation damage in cotton paper, 

Degradation of historical paper induced by synchrotron X‑ray technical examination

2/ Alerting and preventing damage: X-ray dose indicator  

Previous work has shown that the parameter directly related to paper damage is the X-ray dose. However, in heritage science it is often impossible for X-ray laboratory instruments users to determine the radiation flux (and spectral range).

The aim of the project MONITOR-X is to develop a reliable, easy-to-use colorimetric indicator, active over the dose ranges conventionally used for analyzing heritage objects, to monitor the amount of X-ray radiation to which they are exposed. The dosimeter will make it possible to monitor information on the irradiation of the artefacts, a kind of passport that will enable a safer analytical protocol, so as to mitigate harmful impact.

The research team consists of researchers from Centre de recherche sur la conservation des collections (CRC-MNHN-CNRS 3224), laboratoire IPANEMA (CNRS- MiC-UVSQ 3461), laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (ENS-Paris-Saclay) and PUMA beamline (Synchrotron SOLEIL)

Post-doc C. Adouama

Financial support FSP

3/ Modelling paper degradation …

The mechanical and chemical stability of paper subjected to environmental attack is a key issue for the longevity of heritage collections. The aim of this research is to develop a kinetic model for predicting the useful life of cellulose-based cultural assets as a function of type of material and climatic environment in which they are stored. The degradation model takes into account various archival and museum contexts, and considers not only the impact of the temperature/humidity, but also that of gaseous pollutants (atmospheric gases and volatile organic compounds) often found in buildings housing collections and in conservation microenvironments.

… for lifetime prediction !

CRC in collaboration with CCI offers tools *** in OPEN ACCESS  *** 

to calculate Paper Permanence and Paper Decay   

The Paper Permanence Calculator serves as a tool for conservators, archivists and librarians to predict the lifespan of printing papers through the application of the concept of isopermanence. Download it at:

The Paper Decay Simulator serves as a tool to predict the rate of deterioration of three types of paper in different climates. 

An update is available! The new version graphically illustrates the variations in the correlation between cellulose chain lengths and paper’s mechanical strength, depending on the different climate scenarios. Download it at:

These tools are also available on the CCI website 

éprouvettes de papier exposées à des COV acides

Credits

J Tétreault

The research team consists of researchers from Centre de recherche sur la conservation des collections (CRC-MNHN-CNRS 3224) and the Canadian Conservation Institute (Ottawa)

Publications 

Modelling the degradation of acidic and alkaline printing paper 

The impact of carbonyl and hydrogen peroxide vapours on cellulose degradation under ambient hygrothermal conditions, 

Modelling considerations for the degradation of cellulosic paper,  

Accurate molar masses of cellulose for the determination of degradation rates in complex paper samples

Conservation

4/ How to restore fire-damaged manuscripts 

Events in which fire has damaged or destroyed cultural heritage have occurred at all times and in all places. In the best-case scenario, even when only the margins of the leaves of a paper are burned, handling the artefact results in irreversible loss of material, thereby resulting in the loss of potentially recoverable information. Despite the extent of the damage, the question of how to restore paper documents damaged by fire remains unanswered.

The aim of the project is to make the partially carbonized edges of the paper, which are the most fragile areas, more resistant to mechanical stress, thus enabling both the study of the text and its digital reproduction. To this end, a green chemistry soft treatment protocol was developed, based on a combination of surface treatments by aerosol deposition of polysiloxanes and nanocellulose films. 

The research team consists of researchers from Centre de recherche sur la conservation des collections (CRC-MNHN-CNRS 3224), Institut de recherche et d’histoire des textes (IRHT CNRS 841) and University of Padova

Manuscrit endommagé par le feu

Credits

M. Zanetti

5/ Strengthening and deacidifying cultural heritage on paper 

Acids are the main source of chemical degradation of paper, resulting in mechanical brittleness. The aim of this research is to develop conservation treatments that simultaneously strengthen and deacidify heritage papers from archives and libraries collections, by utilizing the properties of a particular class of polymerizable organic molecules, the aminoalkylalkoxysilanes, also known as “AAAS” or ”3AS”.

Our research on AAAS treatment has shown that deacidification is always effective, and the mechanical strength of pure cellulosic papers, such as those made from rag pulp (medieval papers) or bleached chemical pulp (modern papers), even old or highly degraded ones, are considerably improved. Older papers containing mechanical pulp, unpurified and rich in lignin, and, what is more, in an advanced state of degradation due to their inherent chemical instability, are the most resistant to treatment. This type of paper is very common in 19th and early 20th century heritage collections. Our recent research on AAAS has focused on the factors affecting their reinforcement efficiency, with a view to proposing ways of optimizing the treatment of these papers. 

The research team consists of researchers from Centre de recherche sur la conservation des collections (CRC-MNHN-CNRS 3224), Laboratoire Analyse, Modélisation, Matériaux pour la Biologie et l’Environnement (CNRS 8587, Université d’Evry Val d’Essonne), Laboratoire de Physicochimie des Polymères et des Interfaces (CY Cergy Paris Université) and Bibiothèque nationale de France. 

PhD N Ferrandin-Schoffel - Renforcement et désacidification de papiers patrimoniaux par des réseaux de copolymères de polyaminoalkylalcoxysilanes. Mécanismes, stabilité et optimisation

PhD C Piovesan - Elaboration de traitements de conservation à base de réseaux de polysiloxanes pour le renforcement et la désacidification simultanés adaptables à différents papiers : exemple des papiers de presse

Post-doct Z Souguir

Financial support FSP (CoMPresSil, Co-Sil-Bib), CNRS, MCC

Publications 

Chemical and physicochemical investigation of an aminoalkylalkoxysilane as strengthening agent for cellulosic materials, 

Strengthening of degraded cellulosic material using a diamine alkylalkoxysilane, 

Paper strengthening by polyaminoalkylalkoxysilane copolymer networks applied by spray or immersion – A model study, 

The impact of paper constituents on the efficiency of mechanical strengthening by polyaminoalkylalkoxysilanes, 

Strengthening naturally and artificially aged paper using polyaminoalkylalkoxysilane copolymer networks, 

Modeling the reactivity of aged paper with aminoalkylalkoxysilanes as strengthening and deacidification agents,

Long-term stability of lignocellulosic papers strengthened and deacidified with aminoalkylalkoxysilanes, 

Routes to improve the strengthening of paper with aminoalkylalkoxysilanes

Seminar

Préserver les premiers papiers industriels. Un (in)soluble casse-tête ?

Traitement AAAS d’une feuille du journal des fabricants de sucre (ex. 1911) par vaporisation aérosol

Credits

C Piovesan