base made from mechanistic pulp contains significant amounts of lignin, a major component in wood. In the presence of light and oxygen lignin reacts to give chickenhearted materials, which is why newsprint and other mechanical paper yellows with age. Paper made from bleached kraft or sulfite pulps does not contain significant amounts of lignin and is therefore better suited for books, documents and other applications where naturalness of the paper is essential.
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It is important to note that just because a paper is made of wood pulp, does not necessarily mean it is any less durable than a rag paper. The factor that determines the maturation behavior of a paper is how it was manufactured, not the original starting time of the fibres.[17] Furthermore, tests sponsored by the Library of Congress prove that all paper is at risk of acid decay, because cellulose itself produces formic, acetic, lactic and oxalic acids.[18]
Mechanical pulping yields almost a tonne of pulp per tonne of dry wood used (which is why mechanical pulps are sometimes referred to as high yield pulps), which is about twice as a lot as chemical pulping....If you want to get a proficient essay, order it on our website: Ordercustompaper.com
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