However free of acid and paper or board may be immediately after manufacture, over time the presence of residual chlorine from bleaching, aluminum sulfate from sizing, or pollutants in the atmosphere may lead to the formation of acid unless the paper or board has been buffered with an alkaline substance. The transfer of acid from an acidic material to a less acidic or pH neutral material. This may occur directly, when the two materials are in intimate contact. For instance, acid may migrate from boards, endpapers, and protective tissues, as well as the paper covers of books and pamphlets to the less acidic paper of the text. In chemistry, a substance capable of forming hydrogen ions when dissolved in water.
Acids can weaken cellulose in paper, board, and cloth, leading to embrittlement.
Acids may also be introduced by migration from other materials or from atmospheric pollution. See also pH and Acid migration. Acrylic - Back to Top A plastic noted for transparency, light weight, weather resistance, color fastness and rigidity. In addition to these qualities, acrylics are important in preservation because of their stability, or resistance to chemical change over time, a characteristic not common to all plastics. Acrylics are available in sheets, films, and resin adhesives.