 | The examples and perspective in this article deal primarily with Poland and do not represent a worldwide view of the subject.(July 2023) |
Acidic paper is paper which was manufactured using acidic substances. [1] Widely used since the mid-nineteenth century, its pages become yellow within years, extremely brittle over decades, and eventually unreadable in the library and archive collections intended to perserve them. [2] This process has been called "slow fire".
In the mid-nineteenth century, a method of paper production became popular in which resin-alum glue was added to the paper pulp, [3] and the aluminum sulphate remaining in the paper, in reaction with water, forms acids. The long chains of plant cellulose, the structural material of paper, naturally decompose upon exposure to air, but this process is greatly accelerated by acids, which catalyze the decomposition (acidic hydrolysis). As the cellulose chains are cut apart, this reduces the tear resistance of the paper, and at the same time increases their cross-linking, making the paper stiff and brittle. [4] Parallel to the degradation under the influence of water, the cellulose chains react with oxygen, also cutting the chains. [5] The lignin in the paper is also oxidized, which yellows the paper.
The gradual and eventually complete deterioration of the paper as the cellulose chains disintegrate is known as "slow fire". Paper acidification may be accelerated by environmental factors, especially nitrogen and sulfur oxides in polluted air. [6]
The process of self-degradation of paper causes fundamental difficulties in safeguarding the collections of archives and libraries. For example, an analysis of the book collections of the Jagiellonian Library, Adam Mickiewicz University in Poznań, Książnica Cieszyńska, the AGH University of Science and Technology and the Cracow University of Technology showed that as much as 90% of the documents published up to 1996 are in the process of acidic degradation. [7] This means that these institutions, established to care for the documented heritage of the past, are failing this mission. [8]
Although the degradation of paper cannot be undone, only slowed, mass deacidification offers hope for conservation. Unfortunately, due to the difficulty of applying this technique and the rapid pace of paper degradation, it is not possible to save all the documents from the 19th and 20th centuries, and it seems necessary to select the most valuable among the endangered documents. Digitization and microfilming are other methods of rescue. Meanwhile, careful sharing and storage practices can prolong the paper's life, such as the use of acid-free storage materials and limiting exposure to light, especially in the UV range. [9]
A large-scale de-acidification project was carried out in Poland, the Acidic Paper Multiannual Government Program [10] of 2000–2008. In 1998, it was proposed jointly by librarians from Jagiellonian Library and chemists from the Faculty of Chemistry of Jagiellonian University, "to save the heritage of Polish culture in the library and archives of the 19th and 20th centuries" (A. Barański, J. Grochowski, A. Manikowski, D. Nałęcz, K. Zamorski). [11]
The American Bookkeeper technology was chosen, using a deacidifying agent of fine crystalline magnesium oxide suspended in an organic liquid perfluoroheptane, neutral to inks, paints and dyes. The technology allows for recycling of the perfluoroheptane. Books are immersed in a de-acidifying bath, allowing the magnesium oxide to penetrate. The bath is vertical for typical-sized books and horizontal for large or heavy items such as magazines or archives. [10] The Paper Clinic of the Jagiellonian Library in Krakow opened in 2005, [12] and can de-acidify 35 tons of library materials annually. [10] A second facility has been operating at the National Library since 2007, with a capacity of 50 tons. [10] [13]
In recent years, most books have been printed on acid-free paper, meeting ISO standard 9706. The use of long-life paper has many benefits, especially for valuable cultural documents.
Cellulose is an organic compound with the formula (C
6H
10O
5)
n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%.
Hydrolysis is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thicker inks, in paste form, are used extensively in letterpress and lithographic printing.
Mass deacidification is a term used in library and information science as one possible measure against the degradation of paper in old books, the so-called "slow fires". The goal of the process is to increase the pH of acidic paper. Although acid-free paper has become more common, a large body of acidic paper still exists in books made after the 1850s; this is because of its cheaper and simpler production methods. Acidic paper, especially when exposed to light, air pollution, or high relative humidity, yellows and becomes brittle over time. During mass deacidification an alkaline agent is deposited in the paper to neutralize existing acid and prevent further decay. Mass deacidification is intended for objects on acidic paper that will be lost if no action is performed.
Rancidification is the process of complete or incomplete autoxidation or hydrolysis of fats and oils when exposed to air, light, moisture, or bacterial action, producing short-chain aldehydes, ketones and free fatty acids.
Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. It is also referred to as data decay, data rot or bit rot. This results in a decline in data quality over time, even when the data is not being utilized.
In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and as a frame material for eyeglasses; it is also used as a synthetic fiber in the manufacture of cigarette filters and playing cards. In photographic film, cellulose acetate film replaced nitrate film in the 1950s, being far less flammable and cheaper to produce.
Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition. Polymers and particularly plastics are subject to degradation at all stages of their product life cycle, including during their initial processing, use, disposal into the environment and recycling. The rate of this degradation varies significantly; biodegradation can take decades, whereas some industrial processes can completely decompose a polymer in hours.
Acid-free paper is paper that, if infused in water, yields a neutral or basic pH. It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin- and sulfur-free. Acid-free paper addresses the problem of preserving documents and preserving artwork for long periods.
Vinegar syndrome, also known as acetic acid syndrome, is a condition created by the deacetylation of cellulose acetates and cellulose triacetate. This deacetylation produces acetic acid, giving off a vinegar odor that gives the condition its name; as well, objects undergoing vinegar syndrome often shrink, become brittle, and form crystals on their surface due to the migration of plasticizers. Vinegar syndrome widely affects cellulose acetate film as used in photography. It has also been observed to affect older magnetic tape, where cellulose acetate is used as a base, as well as polarizers used in liquid-crystal display units and everyday plastics such as containers and tableware. High temperatures and fluctuations in relative humidity have been observed to accelerate the process. The process is autocatalytic, and the damage done by vinegar syndrome is irreversible.
Preservation of documents, pictures, recordings, digital content, etc., is a major aspect of archival science. It is also an important consideration for people who are creating time capsules, family history, historical documents, scrapbooks and family trees. Common storage media are not permanent, and there are few reliable methods of preserving documents and pictures for the future.
The Brittle Books Program is an initiative carried out by the National Endowment for the Humanities at the request of the United States Congress. The initiative began officially between 1988 and 1989 with the intention to involve the eventual microfilming of over 3 million endangered volumes.
William James Barrow was an American chemist and paper conservator, and a pioneer of library and archives conservation. He introduced the field of conservation to paper deacidification through alkalization.
Cellulose acetate film, or safety film, is used in photography as a base material for photographic emulsions. It was introduced in the early 20th century by film manufacturers and intended as a safe film base replacement for unstable and highly flammable nitrate film.
The sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg2+), and ammonium (NH4+). The lignin is converted to lignosulfonates, which are soluble and can be separated from the cellulose fibers. For the production of cellulose, the sulfite process competes with the Kraft process which produces stronger fibers and is less environmentally costly.
Forensic polymer engineering is the study of failure in polymeric products. The topic includes the fracture of plastic products, or any other reason why such a product fails in service, or fails to meet its specification. The subject focuses on the material evidence from crime or accident scenes, seeking defects in those materials that might explain why an accident occurred, or the source of a specific material to identify a criminal. Many analytical methods used for polymer identification may be used in investigations, the exact set being determined by the nature of the polymer in question, be it thermoset, thermoplastic, elastomeric or composite in nature.
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses, or other vegetable sources in water, draining the water through a fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency, and security paper, or in a number of industrial and construction processes.
Inherent vice is the tendency in physical objects to deteriorate because of the fundamental instability of the components of which they are made, as opposed to deterioration caused by external forces. All objects have some kind of inherent vice as a result of the baseline law of entropy.
The conservation and restoration of books, manuscripts, documents, and ephemera is an activity dedicated to extending the life of items of historical and personal value made primarily from paper, parchment, and leather. When applied to cultural heritage, conservation activities are generally undertaken by a conservator. The primary goal of conservation is to extend the lifespan of the object as well as maintaining its integrity by keeping all additions reversible. Conservation of books and paper involves techniques of bookbinding, restoration, paper chemistry, and other material technologies including preservation and archival techniques.
The conservation and restoration of film is the physical care and treatment of film-based materials. These include photographic film and motion picture film stock.
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