The most complex of the carbohydrates, cellulose is present in the cell walls of all plants. Because of their strength, cells with thick walls have been used in various industries. Besides the natural product being used in the textile industry, artificial fibers are derived directly from cellulose as well as countless other products. Cellulose chemistry is an important phase of organic chemistry.
Cotton, a very pure form of cellulose, has been used for a very long time in the production of artificial fibers and other cellulose products. Wood is another very available source. When certain woods are treated with concentrated acids or alkalis, the bond between the wood fibers and the lignin, which cements them together, is broken, and the fibers, which are pure cellulose, can be removed.
These fibers may then be reorganized as paper, or they may be treated further chemically. If the chemical treatment merely causes the dissolution of the fiber into its component molecules, these molecules may be synthesized into artificial fibers or converted into cellulose plastics. But if the molecules themselves are broken down, their component elements, carbon, hydrogen and oxygen, may be recombined to form wood sugar. Thereafter the wood sugar may be transformed into yeast or alcohol and thus become available for food or as the raw material for numerous industrial products.
Paper and Paper Industry
Cotton, a very pure form of cellulose, has been used for a very long time in the production of artificial fibers and other cellulose products. Wood is another very available source. When certain woods are treated with concentrated acids or alkalis, the bond between the wood fibers and the lignin, which cements them together, is broken, and the fibers, which are pure cellulose, can be removed.
These fibers may then be reorganized as paper, or they may be treated further chemically. If the chemical treatment merely causes the dissolution of the fiber into its component molecules, these molecules may be synthesized into artificial fibers or converted into cellulose plastics. But if the molecules themselves are broken down, their component elements, carbon, hydrogen and oxygen, may be recombined to form wood sugar. Thereafter the wood sugar may be transformed into yeast or alcohol and thus become available for food or as the raw material for numerous industrial products.
Paper and Paper Industry
A very important use of cellulose is in the manufacture of paper, a very old industry. The word “paper” comes from the Latin “papyrus” the name of a sedge, the pith of which was used for paper in 2400 B.C. Egypt. However paper was first made in China. The industry spread from China to India, Persia and Arabia and then through Spain to other European countries. The first paper mill in the United States was in 1690 at Philadelphia.
Raw Materials
Raw Materials
The paper making value of the various fibers depends on the amount, nature, softness and pliability of the cellulose present in the cell walls. This cellulose may occur alone or in combination with lignin or pectin. Wood fibers, cotton and linen are the principal raw materials.
Wood Fibers
Wood Fibers
Wood began being used in the paper industry from about 1850. Today wood has largely replaced the other fibers and furnishes over 90 percent of all the paper manufactured in the Untied States.Spruce is a very important source of wood pulp and has furnished about 30 percent of the total supply. It is ideal because it has all the requirements of a good pulpwood.
The fibers are long and strong with a maximum content of cellulose. The wood is almost free from resins, gums and tannins; and it is light colored, sound and usually free from defects. Red spruce, Picea rubens, white spruce, P. glauca and Sitka spruce, P. sitchensis, are the main species.
The fibers are long and strong with a maximum content of cellulose. The wood is almost free from resins, gums and tannins; and it is light colored, sound and usually free from defects. Red spruce, Picea rubens, white spruce, P. glauca and Sitka spruce, P. sitchensis, are the main species.
The southern yellow pine, Pinus australis, is another important pulpwood. The eastern hemlock, Tsuga canadensis, is a main species in the Lake States while the western hemlock, T. heterophylla is important on the Pacific Coast. Other species include aspen, Populus grandidentata and P. tremuloides, and balsam fir, Abies balsamea. Of lesser importance are jack pine, Pinus banksiana, tamarack, Larix laricina, white fir, Abies concolor, and several hardwoods among which are the beech, Fagus grandifolia, sugar maple, Acer saccharum, and birch, Betula lutea. Sawmill waste is also an increasingly valuable source of wood pulp.
Cotton and Linen
Up to the middle of the 19th Century rags of cotton and linen were the only source of paper, and they are still used for making the finest grades. Cotton fibers have a high felting power and a high cellulose content of about 91 percent. Rags and raw cotton in the form of fuzz or linters are utilized. Flax fibers, that comprise linen, contain 82 percent of pectocellulose and yield a paper of great strength, closeness of texture and durability. Textile waste may also be used. In the preparation of rag pulp the material is sorted, cut into small pieces and freed from dust. It is then boiled in caustic soda to remove the grease and dyes.
For more information please visit website: www.faculty.ucr.edu
Cotton and Linen
Up to the middle of the 19th Century rags of cotton and linen were the only source of paper, and they are still used for making the finest grades. Cotton fibers have a high felting power and a high cellulose content of about 91 percent. Rags and raw cotton in the form of fuzz or linters are utilized. Flax fibers, that comprise linen, contain 82 percent of pectocellulose and yield a paper of great strength, closeness of texture and durability. Textile waste may also be used. In the preparation of rag pulp the material is sorted, cut into small pieces and freed from dust. It is then boiled in caustic soda to remove the grease and dyes.
For more information please visit website: www.faculty.ucr.edu
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