An investigation into the deacidification of paper by ethoxymagnesium ethylcarbonate

Abstract

Aspects of the procedure used since 1995 by the British Library whereby paper is deacidified with ethoxymagnesium ethylcarbonate (EMEC) in hexamethyldisiloxane (HMDS) have been studied using scanning electron microscopy (SEM) along with energy dispersive X-ray analysis (EDAX), X-ray fluorescence (XRF) spectrometry and particle-induced X-ray emission (PIXE). The treatment was applied to three types of test paper, and the analytical results compared with those for similar samples treated using a method which mimicked as closely as possible the library's previous deacidification procedure; this involved the use of the now-banned solvent trichlorofluoroethane. The amount of EMEC distributed over the whole paper sample was fairly consistent for each paper type, but microscopically it was found to be congealed into large deposits, possibly hydrolysed by moisture in the paper, and not distributed as evenly among the paper fibres as is either desirable or possible. The depth of penetration of the EMEC particles obtained by spraying only one side of the paper is found to be poor for paper of heavy gauge and high moisture content, the thinnest samples retaining little alkaline buffer. The results obtained by the newer procedure were similar to those obtained by the older one, and no HMDS either reacted with, or remained in, the paper despite the relatively long drying time.