Unlike metals or glass, paper cannot be continuously recycled, because the fibres will gradually break down in the repeated pulping process.
It was cheaper than the old writing materials, but still expensive. Bleach may be added at this stage, or colorings. A variety of sizings, generally rosins and gums, is available depending on the eventual use of the paper. In paper-making a dilute suspension of fibers in water is drained through a screen, so that a mat of randomly interwoven fibers is laid down.
After the water was first squeezed out, the sheet would be placed between cloths, pressed, and then dried in air.
Uses of paper
First American paper mill was established in By the end of the 15th century, paper mills existed in Italy, France , Germany , and England , and by the end of the 16th century, paper was being made throughout Europe. In the earliest days of paper making, this was done by hanging the sheets like laundry; in more modern times, various forms of heated drying mechanisms are used. The chips dissolve into pulp in the solution. Paper is also measured by caliper thickness and density. Paper making[ change change source ] Modern paper is normally made from wood pulp. Facts about Paper Interesting and Fun Facts about Paper Chinese were the first nation in the world who started producing paper by hand. Recycled wastepaper including newsprint and paperboard are also important sources. It reached Central Asia by and Baghdad by , and by the 14th century there were paper mills in several parts of Europe. For other special papers, or where wood is not available, manufacturers may use pressed sugarcane, bamboo, manila rope, cereal straws, esparto grass, or other fibers.
Some plants other than trees are suitable for paper-making. A large machine may have from 40 to 70 drying cylinders.
The remaining water is removed by evaporation, and the dry sheet is further compressed and, depending upon the intended use, coated or impregnated with other substances.
Tekhnologiia bumagi. Books, magazines and newspapers are printed on paper. Gloss papers give the highest optical density in the printed image.
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