Critical evaluation of approaches toward mass deacidification of paper by dispersed particles

Mass deacidification has been an important topic in cellulose science and will continue to be a critical issue as long as acidic books and paper-based materials are-a often major-part of library and archive stocks. Different means are available to judge the result of a deacidification treatment and to address its sustainability and efficacy. The present study compares deacidification by dispersed particles with procedures that apply homogeneously dissolved alkaline compounds, both under humid and dry accelerated aging conditions. Analysis by size-exclusion chromatography coupled to light scattering detection is used in combination with accelerated aging. The number of chain scissions, i.e. cellulose degradation, is the parameter used for evaluation, expressed as stabilization factors relative to the non-treated specimen. Upon deacidification with homogeneous solutions stability factors of about four were reached, while deacidification with dispersed particles gave only two times longer life times (stability factor of two). Mechanistic aspects are discussed in terms of alkaline reserve, cellulose degradation and mobilities of deacidification agents.