Background: Assessment of the permanence of recycled paper is a current research area at the Library of Congress Preservation Research and Testing Division (PRTD). Awareness of environmental issues has led many countries to implement government mandates for recycling of postconsumer paper products. In the United States, Executive Order 12873, “Federal Acquisition, Recycling, and Waste Prevention,” (1993) established new requirements for federal paper purchases; Section 504 requires the government to use printing and writing papers that include at least 30 percent post-consumer recycled material. While recycled paper has environmental and economic advantages, for libraries and archives, where long-term storage and use of written materials and records is critical, commensurate changes in optimum permanence properties raise concerns. One concern is that the shorter fibers produced by the recycling process, when included in the final paper stock, could contribute to a reduction in strength in the final paper product.
Current recycled paper research is focused on assessing the impact of recycled content percent, quality, repeated recycling) on papers’ mechanical properties, and chemical stability. This research will address the issue of whether papers containing post-consumer recycled fibers are less durable than similar papers produced from virgin fiber pulp, as well as the effect of varying amounts of recycled pulp (a minimum of 30%), on the longevity of records and other collection items printed on this paper.
Nancy Bell, Jana Kolar, Dianne van der Reyden, Preservation in the Digital Age: A Discussion about Conservation in Libraries and Archives, Getty Conservation Institute Newsletter, Fall (2007)
James H. Billington (Librarian of Congress), Trudy Huskamp Peterson (Acting Archivist of the United States), Micheal F. Dimario (Public Printer), Final Report to Congress on the Joint Resolution to Establish a National Policy on Permanent Papers, December 31, 1995.
C.J. Shahani, S.B. Lee, F.H. Hengemihle, G. Harrison, P. Song, M.L. Sierra, C.C. Ryan, N. Weberg, “Accelerated aging of paper: I: Chemical analysis of degradation products, II. Application of Arrhenius relationship, III: Proposal for a new accelerated aging test, ” Preservation Research and Testing Division, Library of Congress, Washington, DC, June (2000).
Project Description: To meet the needs of the Library of Congress and other cultural institutions responsible for standards of permanence, and tasked with maintaining historical records for posterity, PRTD will determine whether papers containing post-consumer recycled fibers are less durable than similar papers produced from virgin fiber pulp. Congruent with PRTD policy and goals, test methods will be non-destructive whenever possible. Results will be disseminated through the Library of Congress Web site and other publications as completed.
Accelerated aging is an essential tool to predict the long-term effects of natural aging and to assess longevity and stability of papers with recycled content. Current standard test methods use controlled-temperature aging at 90ºC and 50% relative humidity. A statistically significant population of samples has been created, and careful mapping of research ovens will help ensure consistent conditions across test samples. Un-aged samples will provide controls for recycled papers with different recycled content. The critical component of the research is to compare the properties and performance of all samples with accepted specifications for permanent papers. A pilot project will assess a range of aging times and aging protocols to assure consistency, reproducibility, and accuracy.
Paper performance will be assessed using physical properties, fold endurance measure of strength loss, and tensile testing for load at break and changes in extensibility. These measures will give information about changes in fiber structure within paper fiber assemblies as an indicator of long-term stability. Changes in visual appearance willbe measured through optical testing, assessing paper darkening or loss of brightness, and determining changes in color. Chemical testing will measure pH, alkaline reserve, degree of polymerization, and viscosity changes. Environmental Electron Scanning Microscopy, high resolution image analysis, Fourier transform infrared spectroscopy, and other methods will be used to assess changes in chemical and mechanical properties, and surface morphology.
A description of this research has been published: Fenella France and Matthew Kullman, Recycled Paper Research at the Library of Congress, International Preservation News (48) 10-16. [PDF: 1 MB, 40 p. (entire issue)]