Paper

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A stack of paper
Paper is thin material used for writing upon, printing upon or packaging, produced by the amalgamation of fibres, typically vegetable fibers composed of cellulose, which are subsequently held together by hydrogen bonding. While the fibres used are usually natural in origin, a wide variety of synthetic fibres, such as polypropylene and polyethylene, may be incorporated into paper as a way of imparting desirable physical properties. The most common source of these kinds of fibres is wood pulp from pulpwood trees. Vegetable fibre materials such as cotton, hemp, linen, and rice are also used.

Papyrus and parchment

The word paper derives from the Greek term for the ancient Egyptian writing material called papyrus, which was formed from beaten strips of papyrus plants. Papyrus was produced as early as 3000 BC in Egypt, and sold to ancient Greece and Rome. The establishment of the Library of Alexandria in the 3rd century BC put a drain on the supply of papyrus. As a result, according to the Roman historian Pliny the Elder (Natural History records, xiii.21), parchment was invented under the patronage of Eumenes of Pergamum to build his rival library at Pergamum. Outside of Egypt, parchment or vellum, made of processed sheepskin or calfskin, replaced papyrus as the papyrus plant requires subtropical conditions to grow.

Early papermaking in China

Main article: Papermaking


Paper is considered to be one of the Four Great Inventions of Ancient China, as the first standard papermaking process was developed in China during the early 2nd century. During the Shang (1600 BC-1050 BC) and Zhou (1050 BC-256 BC) dynasties of ancient China, documents were ordinarily written on bone or bamboo (on tablets or on bamboo strips sewn and rolled together into scrolls), making them very heavy and awkward to transport. The light material of silk was sometimes used, but was normally too expensive to consider. Indeed, most of the above materials were rare and costly. While the Han Dynasty Chinese court official Cai Lun is widely regarded to have first invented the modern method of papermaking (inspired from wasps and bees) from wood pulp in 105 AD, the discovery of specimens bearing written Chinese characters in 2006 at north-west China's Gansu province suggest that paper was in use by the ancient Chinese military more than 100 years before Cai in 8 BC. [1] Archeologically however, true paper without writing has been excavated in China dating to the reign of Emperor Wu of Han from the 2nd century BC, used for purposes of wrapping or padding protection for delicate bronze mirrors.[1] It was also used for safety, such as the padding of poisonous 'medicine' as mentioned in the official history of the period.[1] Although paper used for writing became widespread by the 3rd century,[2] paper continued to be used for wrapping (and other) purposes.

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The world's earliest known printed book (using woodblock printing), the Diamond Sutra of AD 868, shows the widespread availability and practicality of paper in China.
Toilet paper was used in China by at least the 6th century AD.[3] In AD 589, the Chinese scholar-official Yan Zhitui (531-591 AD) once wrote: "Paper on which there are quotations or commentaries from Five Classics or the names of sages, I dare not use for toilet purposes".[3] An Arab traveler to China once wrote of the curious Chinese tradition of toilet paper in AD 851, writing: "They (the Chinese) are not careful about cleanliness, and they do not wash themselves with water when they have done their necessities; but they only wipe themselves with paper".[3] Toilet paper continued to be a valued necessity in China, since it was during the Hongwu Emperor's reign in AD 1393 that the Bureau of Imperial Supplies (Bao Chao Si) manufactured 720,000 sheets of toilet paper for the entire court (produced of the cheap rice-straw paper).[3] For the emperor's family alone, 15,000 special sheets of paper were made, in light yellow tint and even perfumed.[3] Even at the beginning of the 14th century, during the middle of the Yuan Dynasty, the amount of toilet paper manufactured for modern-day Zhejiang province alone amounted to ten million packages holding 1000 to 10000 sheets of toilet paper each.[3] During the Tang Dynasty (AD 618-907) paper was folded and sewn into square bags to preserve the flavor of tea.[1] During the same period, it was written that tea was served from baskets with multi-colored paper cups and paper napkins of different size and shape.[1] During the Chinese Song Dynasty (AD 960-1279) not only did the government produce the world's first known paper-printed money, or banknote (see Jiaozi and Huizi), but paper money bestowed as gifts to deserving government officials were wrapped in special paper envelopes.[3]

In America, archaeological evidence indicates that paper was invented by the Mayans no later than the 5th century AD.[4] Called amatl, it was in widespread use among Mesoamerican cultures until the Spanish conquest. In small quantities, traditional Maya papermaking techniques are still practiced today.

Paper spread slowly outside of China; other East Asian cultures, even after seeing paper, could not figure out how to make it themselves. Instruction in the manufacturing process was required, and the Chinese were reluctant to share their secrets. The paper was thin and translucent, not like modern western paper, and thus only written on one side. Books were invented in India, of Palm leaves (where we derive the name leaf for a sheet of a book). The technology was first transferred to Korea in 604 and then imported to Japan by a Buddhist priests, around 610, where fibres (called bast) from the mulberry tree were used.

Papermaking arrives in the Middle East

After further commercial trading and the defeat of the Chinese in the Battle of Talas in 751, the invention spread to the Middle East.[5] Production was started in Baghdad, where the Arabs invented a method to make a thicker sheet of paper. The manufacture had spread to Damascus by the time of the First Crusade in the 11th century, but the wars interrupted production, and it split into two centers. Cairo continued with the thicker paper. Iran became the center of the thinner papers. It was also adopted in India. The first paper mill in Europe was in Spain, at Xavia (modern Valencia) in 1120. More mills appeared in Fabriano Italy in about the 13th century, as an import from Islamic Spain. They used hemp and linen rags as a source of fibre. The oldest known paper document in the West is the Mozarab Missal of Silos from the 11th century, probably written in the Islamic part of Spain. Paper is recorded as being manufactured in both Italy and Germany by 1400, just about the time when the woodcut printmaking technique was transferred from fabric to paper in the old master print and popular prints.

Some historians speculate that paper was a key element in cultural advancement. According to this theory, Chinese culture was less developed than the West in ancient times prior to the Han Dynasty because bamboo, while abundant, was a clumsier writing material than papyrus; Chinese culture advanced during the Han Dynasty and subsequent centuries due to the invention of paper; and Europe advanced during the Renaissance due to the introduction of paper and the printing press.

Nineteenth Century advances in papermaking

Paper remained expensive, at least in book-sized quantities, through the centuries, until the advent of steam-driven paper making machines in the 19th century, which could make paper with fibres from wood pulp. Although older machines predated it, the Fourdrinier paper making machine became the basis for most modern papermaking. Together with the invention of the practical fountain pen and the mass produced pencil of the same period, and in conjunction with the advent of the steam driven rotary printing press, wood based paper caused a major transformation of the 19th century economy and society in industrialized countries. With the introduction of cheaper paper, schoolbooks, fiction, non-fiction, and newspapers became gradually available by 1900. Cheap wood based paper also meant that keeping personal diaries or writing letters became possible and so, by 1850, the clerk, or writer, ceased to be a high-status job.

The original wood-based paper was more acidic and more prone to disintegrate over time, through processes known as slow fires. Documents written on more expensive rag paper were more stable. Mass-market paperback books still use these cheaper mechanical papers (see below), but book publishers can now use acid-free paper for hardback and trade paperback books.

Papermaking

Chemical pulping

The purpose of a chemical pulping process is to break down the chemical structure of lignin and render it soluble in the cooking liquor, so that it may be washed from the cellulose fibres. Because lignin holds the plant cells together, chemical pulping frees the fibres and makes pulp. The pulp must be bleached to produce white paper for printing, painting and writing. Chemical pulps tend to cost more than mechanical pulps, largely due to the low yield, 40-50% of the original wood. Since the process preserves fibre length, however, chemical pulps tend to make stronger paper. Another advantage of chemical pulping is that the majority of the heat and electricity needed to run the process is produced by burning the lignin removed during pulping.

Papers made from chemical wood-based pulps are also unhelpfully known as woodfree papers.

The Kraft process produces especially strong, unbleached papers that can be used directly for bags and boxes but are often processed further, e.g. to make corrugated cardboard.

Mechanical pulping

There are two major mechanical pulps, thermomechanical pulp (TMP) and mechanical pulp. The latter is known in the USA as groundwood pulp. In the TMP process, wood is chipped and then fed into large steam-heated refiners where the chips are squeezed and fibreized between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones and fibreized. Mechanical pulping does not remove the lignin, so the yield is very high, >95%, but also causes paper made from this pulp to yellow and become brittle over time. Mechanical pulps have rather short fibre lengths and produce weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than chemical pulp.

Recycled paper

Paper recycling processes can use either chemical or mechanical pulp. By mixing with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre in the interests of quality.

Additives

Besides the fibres, pulps may contain fillers such as chalk or china clay, which improve the characteristics of the paper for printing or writing. Additives for sizing purposes may be mixed into the pulp and/or applied to the paper web later in the manufacturing process. The purpose of sizing is to establish the correct level of surface absorbency to suit the ink or paint.

Drying

After the paper web is produced, the water must be removed from it in order to create a usable product. This is accomplished through pressing and drying. The methods of doing so vary between the different processes used to make paper, but the concepts remain the same.

Pressing the sheet removes the water by force. Once the water is forced from the sheet, another absorbent material must be used to collect this water. On a paper machine this is called a felt (not to be confused with the traditional felt). When making paper by hand, a blotter sheet is used.

Drying involves using air and or heat to remove water from the paper sheet. In the earliest days of papermaking this was done by hanging the paper sheets like laundry. In more modern times, various forms of heated drying mechanisms are used. On the paper machine, the most common is the steam-heated can dryer. These dryer cans heat to temperatures above 200°F (93°C) and are used in long sequences of more than 40 cans. The heat produced by these can easily dry the paper to less than 6% moisture.

Finishing

The paper may then undergo sizing to alter its physical properties for use in various applications.

Paper at this point is uncoated. Coated paper has a thin layer of material such as china clay applied to one or both sides in order to create a surface more suitable for high-resolution halftone screens. (Uncoated papers are rarely suitable for screens above 150 lpi.) Coated or uncoated papers may have their surfaces polished by calendering. Coated papers are divided into matt, semi-matt or silk, and gloss. Gloss papers give the highest optical density in the printed image.

The paper is then fed onto reels if it is to be used on web printing presses, or cut into sheets for other printing processes or other purposes. The fibres in the paper basically run in the machine direction. Sheets are usually cut "long-grain", i.e. with the grain parallel to the longer dimension of the sheet.

All paper produced by Fourdrinier-type machines is wove paper, i.e. the wire mesh that transports the web leaves a pattern that has the same density along the paper grain and across the grain. Textured finishes, watermarks and wire patterns imitating hand-made laid paper can be created by the use of appropriate rollers in the later stages of the machine.

Wove paper does not exhibit "laidlines", which are small regular lines left behind on paper when it was handmade in a mould made from rows of metal wires or bamboo. Laidlines are very close together. They run perpendicular to the "chainlines", which are further apart. Handmade paper similarly exhibits "deckle edges", or rough and feathery borders.[6]

Applications

  • To write or print on: the piece of paper becomes a document; this may be for keeping a record (or in the case of printing from a computer or copying from another paper: an additional record) and for communication; see also reading.
Paper can be produced with a wide variety of properties, depending on its intended use.[7]

Types & Weight

Paper is often characterized in terms of weight. In the United States, printing paper is generally 20lb., 24lb., or 32lb. at most. Cover stock is generally 68lb., and 110lb. or more is considered card stock. The weight of 500 sheets of a given paper is the denominating measure of thickness.

The future of paper

Some manufacturers, notably AMD, have started using a new, significantly more environmentally friendly alternative to expanded plastic packaging made out of paper, known commercially as paperfoam. The packaging has very similar mechanical properties to some expanded plastic packaging, but is biodegradable and can also be recycled with ordinary paper. [2]

With increasing environmental concerns about synthetic coatings (such as PFOA) and the higher prices of hydrocarbon based petrochemicals, there is a focus on zein (corn protein) as a coating for paper in high grease applications such as popcorn bags. [3]

Synthetics such as Tyvek and Teslin have been introduced as printing media as a more durable material than paper.

In 2006, the world's first "Paper Technology Centre" was opened in Heidenheim, Germany, the headquarters of the Voith paper machine company, at the cost of 75 million Euros [4].

Notes

1. ^ Needham, Volume 4, 122.
2. ^ Needham, Volume 4, 1.
3. ^ Needham, Volume 4, 123.
4. ^ The Construction of the Codex In Classic- and Postclassic-Period Maya Civilization Maya Codex and Paper Making
5. ^ Meggs, Philip B. A History of Graphic Design. John Wiley & Sons, Inc. 1998. (pp 58) ISBN 0-471-291-98-6
6. ^ "Document Doubles" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada
7. ^ Grades and uses of paper. Retrieved on 2007-10-12.

References

  • Needham, Joseph (1986). Science and Civilization in China: Volume 5, Chemicals and Chemical Technology, Part 1, Paper and Printing. New York: Cambridge University Press, 1985. (also published in Taipei: Caves Books, Ltd., 1986.)
:also referred to as:
  • Tsien, Tsuen-Hsuin, '"Paper and Printing," vol. 5 part 1 of Needham, Joseph Science and Civilization in China:. Cambridge University Press, 1986. ISBN 0521086906. (also published in Taipei: Caves Books, Ltd., 1986.)
  • "Document Doubles" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada

See also

External links

For other meanings of fiber/fibre please see Fiber (disambiguation).


Fiber or fibre[1] is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.
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Cellulose is an organic compound with the formula (C6H10O5)n. It is a structural polysaccharide derived from beta-glucose.[1][2] Cellulose is the primary structural component of green plants.
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hydrogen bond is a special type of dipole-dipole bond that exists between an electronegative atom and a hydrogen atom bonded to another electronegative atom. This type of bond always involves a hydrogen atom, thus the name.
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Wood pulp is a dry fiberous material prepared by chemically or mechanically separating the fibers which make up wood. Pulp can be either fluffy or formed into thick sheets. The latter form is used if the pulp must be transported from the pulp mill to a paper mill.
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Pulpwood refers to timber grown with the principal purpose of making wood pulp for paper production. However, pulpwood is also used as the raw material for some wood products, such as oriented strand board (OSB), and there is an increasing demand for pulpwood as a source of 'green
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Synthenoids are field crops grown for their fibers, which are used to make paper[1], cloth, or rope. These crops are generally harvestable after a single growing season, as opposed to trees which are typically grown for many years before being harvested for wood pulp
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Cotton is a soft fibre that grows around the seeds of the cotton plant (Gossypium sp.), a shrub native to tropical and subtropical regions around the world, including the Americas, India, and Africa.
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Hemp (from Old English hænep, see cannabis (etymology)) is the common name for plants of the genus Cannabis, although the term is often used to refer only to Cannabis strains cultivated for industrial (non-drug) use.
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Linen is a material made from the fibers of the flax plant.'''

Flax fiber

The term "linen" refers to yarn and fabric made from flax fibers; however, today it is often used as a generic term to describe a class of woven bed, bath, table and kitchen textiles because
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RICE is a treatment method for soft tissue injury which is an abbreviation for Rest, Ice, Compression and Elevation.[1][2][3] When used appropriately, recovery time is usually shortened and discomfort minimized.
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Gumhūriyyat Miṣr al-ʿArabiyyah
Arab Republic of Egypt


Flag Coat of arms
Anthem
Bilady, Bilady, Bilady
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Papyrus is an early form of thick paper-like material produced from the pith of the papyrus plant, Cyperus papyrus, a wetland sedge that was once abundant in the Nile Delta of Egypt.
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C. papyrus

Binomial name
Cyperus papyrus
L.

Papyrus sedge, also known as Bulrush or Paper reed (Cyperus papyrus) is a monocot belonging to the sedge family Cyperaceae.
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Eleftheria i thanatos  
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Royal Library of Alexandria in Alexandria, Egypt, was once the largest library in the world.

It is generally thought to have been founded at the beginning of the 3rd century BC, during the reign of Ptolemy II of Egypt.
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Gaius or Caius Plinius Secundus, (AD 23 – August 24, AD 79), better known as Pliny the Elder, was an ancient author, naturalist or natural philosopher and naval and military commander of some importance who wrote Naturalis Historia.
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Parchment is a thin material made from calfskin, sheepskin or goatskin. Its most common use is as the pages of a book, codex or manuscript. It is distinct from leather in that parchment is not tanned, but stretched, scraped, and dried under tension, creating a stiff white,
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Eumenes II of Pergamon (ruled 197 - 158 BC) was king of Pergamon and a member of the Attalid dynasty. The son of king Attalos I and queen Apollonis (?), he followed on his father's footsteps and collaborated with the Romans to oppose first Macedonian, then Seleucid
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Pergamon(Πέργαμος)
Ancient City of Greece
(Bergama)

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Parchment is a thin material made from calfskin, sheepskin or goatskin. Its most common use is as the pages of a book, codex or manuscript. It is distinct from leather in that parchment is not tanned, but stretched, scraped, and dried under tension, creating a stiff white,
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Vellum (from the Old French Vélin, for "calfskin"[1]) is a sort of processed animal hide as a material for use in producing written works in the scroll, codex or book form in the pre-printing Age using joined pages, characterized by its thin, smooth, durable
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calf (plural calves) is the young of a certain species of mammal. The term is most commonly used to refer to the young of cattle. The young of bison, camels, dolphins, elephants, giraffes, hippopotamuses, moose, rhinoceroses, whales, and yaks, also are called calves.
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Papermaking is the process of making paper, a material which is ubiquitous today for writing and packaging. Though the word "paper" derives from the Egyptian use of papyrus. Amate paper, resembling papyrus, was also invented independently by the Mayas around the 5th century AD.
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Four Great Inventions of ancient China (Traditional Chinese: 四大發明; Simplified Chinese: 四大发明; Pinyin:
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Shang Dynasty (Chinese: ) or Yin Dynasty () (ca. 1750 BC - ca. 1045 BC) is the second historic Chinese dynasty and ruled in the northeastern region of the area known as "China proper", in the Yellow River valley.
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      Zhou Dynasty (Chinese: ; Pinyin: Zhōu Cháo; Wade-Giles: Chou Ch`ao; 1123 BC to 256 BC[1]) preceded by the Shang Dynasty and followed by the Qin Dynasty in China.
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