Fibers

David S. Seigler Department of Plant Biology University of Illinois Urbana, Illinois 61801 USA seigler@life.illinois.edu http://www.life.illinois.edu/seigler

Fibers from plants - Outline Importance o Historical o Present-day o Synthetic fibers Botanical o What are fibers? o Plant families

Fiber types o Seed hairs or fibers + Isolation and processing o Soft or bast fibers o Hard or vascular fibers

Other classifications o Textile or apparel fibers o Plaiting or coarse fibers + Cordage fibers + Brushes or braiding fibers + Stuffing materials + Paper Economic Importance

Reading CHAPTER 15 IN THE TEXT, 355 ff.

Introduction Cotton fibers were gathered, spun and twisted at least 10,000 years ago in Peru. Flax was woven and domesticated in the Near East at least 8000 years ago (at least 1000 years before the domestication of sheep).

Animal fibers such as wool have also been widely used Animal fibers such as wool have also been widely used. Flax replaced wool in Europe for clothing. To a botanist, a fiber is an elongated cell with thick walls and tapering ends. In commerce, fibers may be single cells or hundreds of cells. Fibers may vary from fractions of a mm to 2 meters in length.

Most plant fibers are comprised of cellulose Most plant fibers are comprised of cellulose. They are more stable to heat than are animal fibers. Plant fibers also have different properties when dyed and usually require more complex treatments to cause adherence of the dyes.

Many fibers are too slick, short or brittle to be spun into threads. Kapok fiber is too slick to spin into thread, but is used to make stuffing or packing. Some fibers are used to make paper.

Fibers can be classified by their uses (see p Fibers can be classified by their uses (see p. 356) or the part of the plant they are from. Fibers are used for textiles, brushes, plaiting or coarse weaving, stuffing material, paper and specialty goods. Cotton, flax, ramie, and hemp are most often used for apparel or textile fibers. Jute, cotton, hemp, abacá, sisal, New Zealand flax, and Mauritius hemp are most often used for cordage.

Istle, sisal, piassava (palm), and broomcorn (a Sorghum bicolor cultivar) are most often used for brushes or braiding fibers. Kapok, cotton, Spanish moss, and jute are most often used for filling fibers.

Bast fibers come from the phloem tissues of dicotyledonous plants. Textile fibers Textile fibers are primarily grouped into seed and fruit fibers; soft or bast fibers; and hard or leaf fibers. Bast fibers come from the phloem tissues of dicotyledonous plants. Hard fibers come from the leaves of certain monocotyledonous plants.

Bast fibers Bast fibers are removed from plant material by retting. The cell walls of soft, bast or true fibers are cellulose and are not easily broken down by bacteria. In retting, the plant material is placed in water or kept wet, while anaerobic bacteria digest away most of the plant tissue except the fibers. See p. 362, 363, 364.

The remaining material is bent sharply to break the remaining vascular material away from the true fibers. The material is then beaten and scraped (scutching) and the fibers combed to align them (hackling).

For hard fibers, the plant material is crushed and soft tissue scraped away. this process is called decorticating. Ginning is used to remove seed fibers from the seeds. The fibers are also combed and cleaned. Fibers may then be bleached or otherwise treated to prepare them for use.

Seed and fruit fibers The most important seed fiber is cotton (Gossypium spp., Malvaceae). Cotton seeds have properties that permit them to be spun into thread. Cotton is the most important fiber in the world today, and is, according to some sources, the most important nonfood plant commodity.

Cotton production today is highly mechanized in most countries Cotton production today is highly mechanized in most countries. This plant produces textiles that dye well and withstand vigorous washings. Cotton is an epidermal hair of the seed coat. There are both short (linters) and long hairs. The short hairs are removed before the seeds are used for oil expression.

Cotton, Gossypium hirsutum, flower and boll

Mature cotton and mature boll

Cotton gin and cotton bales in Oklahoma

Cotton was domesticated in both the Old and New World (different species). The ancestry of cotton is complex and there is not complete agreement about these origins. Cotton was domesticated in south central Asia and fabrics from Pakistan appear about 3000 B.C. These were from either G. arboreum or G. herbaceum. By the 15th century, cultivation of these two species had reached into Europe from the Arabs. Both have largely been replaced by New World cultivars.

Two species of cotton were also domesticated in the New World. Both involve an Old World parent; genes from this parent are now estimated to have arrived in the Americas more than one million years ago. Columbus observed cotton in the New World when he came to America. Gossypium hirsutum (upland or West Indian) cotton accounts for 95% of the cotton cultivated.

G. barbadense, sea island, Egyptian, or Pima cotton was probably cultivated earlier and was used by about 8000 B.C. Weaving was an integral part of the culture in the Inca Empire in the 13th and 14th centuries.

Cotton did not become a major crop, however, until 1794 when Eli Whitney invented the cotton gin. Cotton then became the major crop in many areas of the Southeastern U.S. The cultivation of cotton was one of the major factors that led to slavery in the U.S.

The invention of the cotton gin permitted cotton to be the basis of a one crop economy. This one crop economy was destroyed by the boll weevil about 1900. Since that time, agriculture has diversified greatly in the South.

Cotton fibers are then processed extensively. See pg. 365 Cotton fibers are then processed extensively. See pg. 365. The fibers are carded, and twisted into slivers. The fibers are then drawn, cleaned (washed with caustic soda), mercerized (soaked with NaOH under pressure), and finally sized with substances such as starch or gels. After being woven, the fabrics are treated with ammonia to reduce shrinkage on washing.

Permanent press fabrics now decrease the need for ironing. The former USSR, China, USA, and India are major cotton producing countries. Cotton seed is widely used as an edible oil source. There are some problems with toxicity however.

Bast fibers Bast or soft fibers are thick walled cells from dicotyledonous plants. The fibers seem to support the phloem cells. Fibers may be up to 2 meters long and are usually isolated by retting. Most can be bleached or dyed.

Jute (Corchorus capsularis, Tiliaceae) Jute is the most common bast fiber and is second only to cotton in terms of production. Jute is widely used for sacking and similar material. The species is native to the Mediterranean from where it spread throughout the Near and Far East. The plants are herbaceous annuals.

Jute fibers don't hold up too well because they are brittle. Today most jute comes from India, China, and Bangladesh.

Jute, Corchorus olitorius, Tiliaceae

Flax (Linum usitatissimum, Linaceae) Flax is one of the oldest fibers used by man. It was used at least 10,000 years ago by the Swiss Lake Dwellers and Egyptian mummies were wrapped in linen 5,000 years ago. Carvings and paintings in their tombs document its cultivation. The Greeks and Romans also used linen and the Romans spread its use throughout Europe. Although flax originated in the Near East, it is not known to occur in the wild today and the exact site of origin is not known.

Flax, Linum usitissimum, Linaceae

The fibers are straight and two to three times as strong as cotton. The cultivation of flax was very important in much of Europe until replaced by other fibers. Cotton only replaced linen in the 1800's.

Cotton has replaced linen mostly because of economics Cotton has replaced linen mostly because of economics. It is easier and cheaper to grow and utilize. Hand processed flax is usually of much better quality than machine processed. Basically, flax and linen have become too expensive for common use in most parts of the world.

Flax is often "dew retted" in the field Flax is often "dew retted" in the field. Retting flax also causes tremendous pollution problems and it is seldom done today in western Europe. Both Belgium and Ireland import most of their flax from Poland and the former Soviet Union. China is another major producer.

Hemp (Cannabis sativa, Cannabaceae) True hemp comes from the same plant as marijuana. The plant has mostly been grown as a fiber and has been cultivated since prehistoric times. It was grown in China as early as 4000 B.C. The fibers are extracted by retting, scutching, and pounding. Typically hemp is used for cordage, rope, canvas, and sailcloth. Jeans were originally made from hemp cloth. Most hemp fiber today comes from the USSR and India.

Hemp, Cannabis sativa, Cannibaceae

Leaf or hard fibers The widespread use of these fibers is fairly recent. As they are comprised of vascular systems, the cells are small and bound together by pectins. They cannot be isolated by retting. They are decorticated. The fibers are too stiff to be used to make fabrics. They make better quality ropes than bast fibers however. Most good quality hard fibers come from Agave or Musa.

Sisal and henequén Sisal comes from the leaves of Agave sisilana and henequén from the leaves of A. fourcroyoides. They are native to Mexico and Central America and the Mayas and Aztecs used them to make crude fabrics. The spines of the plant were used for needles.

Sisal, Agave sisilana, Agavaceae, in Tamaulipas, Mexico Courtesy Dr. Ken Glander

Harvesting and transporting sisal leaves Courtesy Axel Walther and Dr. Ken Glander

The leaves are cut at the base, carried to the factory, rolled and the water squeezed out, and the other mushy tissues scraped away from the fibers. The fibers are then washed and hung out in the sun. They can be dyed directly.

Decorticating leaves of sisal Courtesy Axel Walther

Sisal fiber bleaching in the sun

Processing sisal fiber Courtesy Axel Walther and Dr. Ken Glander

Although henequén is still mostly grown in Mexico, sisal is now cultivated in many parts of the world. Sisal is important in Brazil, East Africa, Madagascar, and other arid areas.

Abacá or Manila hemp (Musa textilis, Musaceae) Abacá is native to southeast Asia. The fibers come mostly from the leaf bases. The plant is now grown in many parts of the tropics. It is used to make things such as "Manila" envelopes as well as cloth. The fibers are isolated in much the same way as those of sisal and henequen.

Abacá or Manila hemp (Musa textilis, Musaceae) http://www.globalhemp.com/News/2004/October/daimler-chrysler-to-use.php www.paperlan.com/paperlan-pulpas.html

Abacá or Manila hemp, Musa textilis, Musaceae http://img.alibaba.com/photo/11156351/Abaca_Natural_Fiber__Manila_Hemp__Musa_Textilis.jpg

Broom corn, Sorghum bicolor, Poaceae Broom corn (Sorghum bicolor) is used to make brushes and brooms.

Many types of fibers are isolated from palms in the tropics. Fibers from palms Many types of fibers are isolated from palms in the tropics. Piassava fiber is a coarse, tough, and water resistant fiber used for brushes, brooms, mats, and cordage. It comes from several species of palms. Crin vegetal comes from a small fan-palm that is common in northwestern Africa.

Crin vegetal, Chamaerops humilis, Arecaceae

Palmetto, Sabal minor, Arecaceae Palmettos were used by many American Indians in the southeastern U.S. as a source of fiber and for construction of houses.