THE STRENGTHENING OF EMBRITTLED BOOKS USING GAMMA-RADIATION

The embrittlement of papers, manufactured through processes introduced in the mid-19th century, has caused many millions of books to become fragile, even to the point of being unusable. During the 1980s the British Library funded a research programme, carried out at the University of Surrey, to develop a technology which could be used to treat brittle books on a large scale, with the goal of greatly extending their useful life. The process developed, known as graft co-polymerization, involves three stages: i) application of a cocktail of monomers to the book's pages; ii) equilibration of these monomers throughout the text block; iii) a low, slow dose of gamma-radiation to effect polymerization. The work at the University of Surrey studied various combinations of monomers, as well as equilibration times and dose regimes; it also examined the environment necessary to achieve polymerization within the pages of the book, whilst leaving it in an otherwise original condition. In collaboration with the British Library, Nordion International has designed a full-scale book-strengthening plant capable of processing between 200,000 and 500,000 books per year, with estimated prices to customers in the region of pound 8-pound 10 per volume (US $12-16). In order to test the equipment and procedures that would be involved in such a plant, pilot-scale equipment has been designed and assembled on the premises of Isotron pie, where use is made of a conventional irradiator. This paper gives details of the graft co-polymerization process, and some results of the pilot-scale work, in terms of both efficacy and controllability. It also discusses the technical and economic feasibility of building and running a full-scale plant.