HISTORICAL NOTE 1450 greatly increased the demand for pa­ Paper and Other Writing per. After about 1750 books were issued for the general public, newspapers and popu­ lar magazines had wide distributions­ and paper mills had difficulty meeting the Materials: Part II demand. Nearly every magazine from 1775 on bore advertisements urging the Paper, a matted or felted sheet made pri­ prayer papers; this job required six years to public to "save your rags:' Obviously, marily of cellulose fibers, is formed on a complete. other materials had to be found. wire screen from water suspension. Due to The art of papermaking reached the Ar­ Naturalist Rene Antoine Ferchault de its low cost and versatility, it has replaced abs in 751, when their city of Samarkand in Reaumur first suggested using wood as a many other materials in a variety of uses. central Asia was attacked by the Chinese. papermaking material to the French Acad­ Paper can be made with many specialized The Arab governor managed to repel the emy in 1719. After observing wasps make properties, some of the most desirable in­ invasion and, while pursuing the retreat­ nests by chewing wood fiber, since they cluding high impact or tear strength, wet ing Chinese army, captured prisoners, could make a paperlike material, he sur­ strength, resistance to water or water va­ some of whom turned out to be papermak­ mised men should be able to imitate the por, resistance to oil and grease, and resist­ ers. Samarkand had all the raw materials process. In 1730 Franz Briickmann printed ance to flames. needed for the large-scale manufacture of a few copies of his geology book on paper Last month's Historical Note followed paper: crops of flax and hemp and plenty made from the rock fiber, asbestos. About the development of writing materials used of water. Baghdad began to produce paper the same time, Remish natural historian by early societies before the invention of in 793. Many 9th century Arabic manu­ Albert Seba suggested using seaweed. In paper. Some cultures used stone, clay scripts written on paper have been pre­ 1741 Jean Etienne Guettard offered swamp bricks, wood, leaves, or bark to preserve served. moss as an alternative. Other possibilities, their words and thoughts; others used the used to varying degrees of success, include sheepskin (parchment), or calfskin or goat­ straw pulp, bagasse (sugarcane residue), skin (vellum); the Egyptians laminated fi­ Mediterranean esparto grass, and crushed brous parts of the papyrus plant. The oldest surviving bamboo. The most thorough investiga­ The Chinese created finely woven cloth samples of paper date tion, though, appeared in six volumes be­ on which they could paint calligraphic tween 1765 and 1771, when the clergyman characters. Still others created felts by mat­ from about A.D. 264. Jacob Christian Schaffer in Germany made ting and intertwining animal hairs. These specimens of paper from 80 vegetable sub­ developments eventually led the Chinese stances he found near his home. His six to create true paper, in which vegetable fi­ Paper was not manufactured in Europe volumes included paper samples made of bers are "felted" together. until 1151, more than a thousand years af­ Indian com husks, pine cones, potatoes, The oldest surviving samples of paper ter its first invention in China. The craft old shingles, reeds, leaves from various date from about A.D. 264, but the Chinese passed from Baghdad to Damascus, trees and plants, wasps nests, moss, vines, court official Ts'ai Lun reported his inven­ Egypt, Morocco, and finally reached the hemp, straw, cabbage stalks, asbestos, tion of papermaking to Emperor Ho-ti in province of Valencia in Spain. A century thistles, burdock stalks, cattails, and turf. A.D. 105. Ts'ai Lun used fibers from old later the Italians learned how to make pa­ In 1800 Matthias Koops published a book rags, mulberry bark, fish nets, and hemp per. By the 14th century, France and Ger­ in England on papers made from straw, de­ waste. The fibers had to be macerated or many had also established paper mills. inked paper, and wood pulp. This publica­ beaten until the individual filaments be­ Papermaking spread to North America tion marked the first use of wood pulp for came separated; the fibers were then sus­ by way of the Conquistadores, who set up practical paper production. In 1841 Charles pended in water and lifted out on a fine a paper mill in Culhuacan, Mexico, in Fenerty of Nova Scotia manufactured the screen. The water drained through the 1575. The first paper manufactured in first ground wood paper, using a mechani­ screen, leaving a thin layer of tangled cellu­ what was to become the United States was cal process to crush wood into usable fi­ lose fibers which, when dried, formed a established in Germantown, Pennsylvania bers. sheet of paper. The technique for forming in 1690. Canada's first paper mill, built in The first chemical process for digesting paper has not been fundamentally altered Quebec in 1803, produced paper for the wood pulp was discovered a decade later in nearly 1,900 years. Montreal Gazette. In these mills, each sheet by Hugh Burgess and Charles Watt, who The Chinese closely guarded their pa­ was individually fabricated. A good cooked wood chips in a solution of caustic permaking process, which remained a na­ worker could make about 750 sheets per soda. In 1857 Benjamin C. Tilghman dis­ tional secret for about 500 years, when the day. covered the "sulfite process;' which used craft finally spread to Korea and Japan, Until this time, most paper was made sulfurous acid (H,SO,) and wood chips, brought by Buddhist monks who demon­ from linen or cotton rags. Rag paper is under high temperature and pressure, strated how to make manuscript books quite durable (cotton has a 91% cellulose with the addition of a base such as calcium from the bark of the paper mulberry tree. content; linen, hemp, and jute vary from to prevent burned batches. Tilghman re­ The Japanese made a thin, tough paper 60 to 90% cellulose). The rags were beaten ceived a patent for his process in 1867, and from a mountain plant called gampi; later by hand with a pestle or mallet until the it became widely used in the following dec­ they also used mitsumata bark and rice fibers were separated. After 1680, auto­ ade, surviving until the 1940s. straw. The first block printing occurred in mated beating machines simplified the In 1884 in Germany, Carl F. Dahl devel­ 770 in Japan, when the Empress Shotoku chore. oped the sulfate pulping process, which commissioned the printing of one million The invention of the printing press in used sodium sulfate instead of soda ash to MRS BULLETIN/JUNE 1991 37 HISTORICAL NOTE produce a stronger pulp. The popular sheets). A ream of "16 pound paper" a new photoengraving process. Coatings name for this was the "kraft process;' from weighs 16 pounds for standard 8 1/2 x 11 also improve the gloss and opacity of pa­ the German word for strong. The kraft inch paper. Paper is also measured by its pers. process has become the dominant pulping thickness and density, and it is segregated Diverse specialty papers are made for method in paper manufacture. It is faster according to gloss, opacity, brightness, continually broadening applications. than other processes and is also practical and color. These papers differ through chemical with a wide range of wood species, though The material properties of paper can be additives and coatings. For instance, it yields a very dark-colored pulp. Not until improved for specific uses. Since paper polyethylene-coated paper remains flexi­ the 1930s was an effective bleaching proc­ composed only of cellulosic fibers is water ble from -65 to 200°F and it also resists crea­ ess found to tum kraft pulp into white pa­ absorbent, water-based inks penetrate and -sing; this makes it ideal for packaging per. Other paper bleaching methods had spread across it, making printing and cal­ applications (bags, boxes, and package lin­ used chlorine since its discovery in 1774. ligraphy difficult. Early paper makers ers), as well as for disposable diapers, bibs, Calcium and sodium hypochlorites were learned how to impregnate the paper with and bed sheets. Papers with a high content also used for bleaching paper stock after various substances to hinder wetting; this of rag fibers are extremely durable and 1800. process is called "sizing:' The Chinese therefore are used for bank notes and secu­ Softwood pulp fibers are 0.12 to 0.2 used starch for sizing as early as 768. By rity notes, filter paper, tracing paper, and inches long, while hardwood fibers are about 1337, other manufacturers used ani­ extremely lightweight special papers for only 0.04 inches. Fiber diameters vary be­ mal glues and gelatins and vegetable printing Bibles and rolling cigarettes. tween 0.0008 to 0.0012 inch. The longer gums. In 1807, Moritz Friedrich Illig pub­ Growing more sophisticated as our com­ softwood fibers give the paper strength lished his discovery in Germany that pa­ munication needs have changed, the pro­ and tear resistance, while the shorter hard­ per could be sized in vats with rosin and duction of paper and writing materials has wood fibers increase the smoothness and alum, though it took another 25 years be­ literally spanned the history of human civi­ opacity of the sheet. The strength and du­ fore anyone put the method to practical lization, going from cave paintings and in­ rability of the finished paper is determined use. dentations marked in clay tablets to by the fibers and the formation and struc­ In the 19th century, papers began to be processed plant materials such as bark ture of the sheet.