Historically valuable paper objects are rapidly deteriorating and their longterm conservation requires a full understanding of the chemical degradation mechanisms to conceive appropriate methodologies for conservation. The main cellulose degradation pathways are the acid hydrolysis of glycosidic bonds and oxidation. Low pH values can lead to cellulose depolymerization even at room temperature. Ancient manuscripts were usually executed by using iron-gallinks. These were obtained by reaction of iron (II) sulfate (i.e. vitriol, as reported in old recipes) with tannins extracted from gall-nuts, to give a pyrogallate complex of iron (III) and sulfuric acid. However, acid-catalyzed hydrolysis of cellulose is not the only paper degradation pathway due to the presence of iron-gall ink. In fact, transition metal ions usually catalyze cellulose oxidation through a free radical mechanism, which produces hydrogen peroxide in situ. This paper reports an investigation on the use of magnesium hydroxide nanoparticles dispersed in alcohols to inhibit two different and synergistic degradation processes usually affecting historically valuable manuscripts and common paper documents. We show that the preservation of paper from acid hydrolysis and oxidative ink corrosion can be achieved by stabilizing the final pH of deacidified paper around 6.5-7.5. PH control may allow to reduce the catalytic action of metals and minimize radical production. The inhibiting action of magnesium hydroxide nanoparticles are compared to magnesium oxide particles present in one of the best mass deacidification method (Bookkeeper).

Hydroxide nanoparticles for deacidification and concomitant inhibition of iron-gall ink corrosion of paper / Rodorico Giorgi; Giovanna Poggi; Nicola Toccafondi; Piero Baglioni. - ELETTRONICO. - XXIV Congresso Nazionale della Società Chimica Italiana - Atti del Congresso:(2011), pp. 86-86. (Intervento presentato al convegno XXIV Congresso Nazionale della Società Chimica Italiana tenutosi a Lecce nel 11-16 Settembre 2011).

Hydroxide nanoparticles for deacidification and concomitant inhibition of iron-gall ink corrosion of paper

GIORGI, RODORICO;POGGI, GIOVANNA;TOCCAFONDI, NICOLA;BAGLIONI, PIERO
2011

Abstract

Historically valuable paper objects are rapidly deteriorating and their longterm conservation requires a full understanding of the chemical degradation mechanisms to conceive appropriate methodologies for conservation. The main cellulose degradation pathways are the acid hydrolysis of glycosidic bonds and oxidation. Low pH values can lead to cellulose depolymerization even at room temperature. Ancient manuscripts were usually executed by using iron-gallinks. These were obtained by reaction of iron (II) sulfate (i.e. vitriol, as reported in old recipes) with tannins extracted from gall-nuts, to give a pyrogallate complex of iron (III) and sulfuric acid. However, acid-catalyzed hydrolysis of cellulose is not the only paper degradation pathway due to the presence of iron-gall ink. In fact, transition metal ions usually catalyze cellulose oxidation through a free radical mechanism, which produces hydrogen peroxide in situ. This paper reports an investigation on the use of magnesium hydroxide nanoparticles dispersed in alcohols to inhibit two different and synergistic degradation processes usually affecting historically valuable manuscripts and common paper documents. We show that the preservation of paper from acid hydrolysis and oxidative ink corrosion can be achieved by stabilizing the final pH of deacidified paper around 6.5-7.5. PH control may allow to reduce the catalytic action of metals and minimize radical production. The inhibiting action of magnesium hydroxide nanoparticles are compared to magnesium oxide particles present in one of the best mass deacidification method (Bookkeeper).
2011
XXIV Congresso Nazionale della Società Chimica Italiana Lecce 11-16 settembre 2011
XXIV Congresso Nazionale della Società Chimica Italiana
Lecce
11-16 Settembre 2011
Rodorico Giorgi; Giovanna Poggi; Nicola Toccafondi; Piero Baglioni
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/544869
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