0000000000917934
AUTHOR
Julio Romero-noguera
Analytical characterisation of the biodeterioration of diterpenoid labdanic varnishes used in pictorial techniques: Sandarac and Manila copal
Abstract The deterioration produced by fungal and bacterial growth on the sandarac and Manila copal, diterpenoid varnishes traditionally used as art materials, was evaluated by gas chromatography–mass spectrometry (GC–MS), and pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS). Test specimens, coated with a solidified thin layer of the studied varnishes, were inoculated and incubated with selected fungi and bacteria obtained from collections and oil paintings affected by biodeterioration, and analysed by the above mentioned techniques. Significant changes were detected, showing evidence of deterioration processes caused or favoured by some of the studied microorganisms.
Estudio del biodeterioro en resinas alquídicas usadas como aglutinante en pinturas modernas mediante espectroscopía FTIR y pirólisis-cromatografía de gases-espectrometría de masas (Py-GC-MS).
Evaluation of the alteration produced by microbiological attack on alkyd resins has been carried out by FTIR spectroscopy and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS). The latter included the online derivatisation of alkyd resins using hexamethyldisilazane during pyrolysis. Specimens consisting of thin films of resins formed on glass slides were used. Analyses performed on the specimens in which different genera of bacteria and fungi were inoculated and allowed to grow, indicate that the attack of microorganisms encourages the scissioning of the polymeric resins and the appearance of short-chain fatty acids. IR bands ascribed to carboxylic acids appearing in samples from in…