FIBERS FROM PLANTS



OUTLINE
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. 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. 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. Some fibers are used to make paper. Others, such as kapok, are too slick to spin into thread and are used to make stuffings or packing.

Fibers can be classified by their uses (see the tables on page 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, abaca`, 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.
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.

Fiber extraction
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 the figures on page 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 ibers 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. Kapok (Ceiba pentandra, Bombacaceae) cannot be used for this purpose and is used for stuffing. Coconut fruit fibers (coïr) are used for brushes and doormats.
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. This plant produces textiles that dye well and withstand vigorous washings.
Cotton is an epidermal hair of the seed coat. There areboth short (linters) and long hairs. The short hairs are removed before the seeds are used for oil expression.
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 may involve an Old World parent, although this is currently debated. 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 in 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 that was destroyed by the boll weevil about 1900. Since that time, agriculture has diversified greatly in the South.

Cotton flowers
Cotton boll

All cottons are perennials in nature, but an annual habit has been selected. Cotton is usually defoliated before harvest today.
Cotton fibers are then processed extensively. See pg. 365. The fibers are carded, and twisted into slivers. They 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.

Coïr
The outside part of coconut fruits serves as a source of fiber for many purposes. The fibers are longer than cotton. Immature coconuts are retted in sea water for 8-10 months. The fibers are usually used to make ropes and matting. The fibers of mature husks (from copra production) are removed in much the same way. The fibers are often decorticated. These are used for mattresses and for brushes.

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

Jute
Jute (Corchorus capsularis, Tiliaceae) is the most common bast fiber and is second only to cotton in terms of production. It 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) flowers

Flax
Flax (Linum usitatissimum, Linaceae) 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. It is hard to say exactly where it originated and is not known to occur in the wild today.
The fibers are straight, smooth 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. 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. 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.

Flax plants with flowers

Flax seed or Iinseed

Hemp
True hemp comes from the same plant as marijuana (Cannabis sativa, Cannabaceae). The plant has mostly been grown as a fiber and has been grown since prehistoric times. It was grown in China as early as 4000 B.C. The fibers are extracted by retting, scutching, and pounding. Typically it 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.

Marijuana

Ramie
Ramie, Boehmeria nivea, Urticaceae, has never been important outside of China because of the difficulty in growing and cleaning up the fibers. Some new processing developments make this more competitive. Gum and pectin must be removed from the fibers. Ramie has been grown for more than 7000 years. The plant is native to Asia.
Ramie fiber is of exceptional strength. The stems now are often decorticated and the process is mostly mechanized.

Ramie

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 heneque`n
Sisal comes from the leaves of Agave sisilana and henequen from the leaves of A. fourcroyoides. They are native to Mexico and Central America and the Mayans and Aztecs used them to make crude fabrics. The spines of the plant were used for needles.
The same plants can be used to make maguey (similar to pulque). 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.
Although henequen 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.

Sisal fields
Sisal plants

Abacá
Abacá or Manila hemp (Musa textilis, Musaceae) 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.

Other minor fibers
Sunn hemp (Crotalaria juncea,Fabaceae or Leguminosae) is mostly grown as a fiber crop in India. It is quite important there.
Istle (Agave lechuguilla, Agavaceae) is used in Northern Mexico to make fibers for brushes, cordage, and upholstery.
Istle

Formio or New Zealand flax (Phormium tenax, Liliaceae) is cultivated in Argentina, Chile, and New Zealand. It gives a soft and pliable fiber.
Sansevieria metalaea or S. guineensis (Liliaceae ) is used locally in Africa.
Spanish moss (Tillandsia usneoides, Bromeliaceae) is used in the South to make stuffing for furniture.
Broom corn (Sorghum bicolor) is used to make brushes and brooms.

Broom corn

Synthetic fibers
Today many purely synthetic fibers are used. Most are based on wood (rayon) or petroleum (dacron, nylon, and many other types).

New Zealand flax




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Revised April 2005


© David S. Seigler, Integrative Biology 363, Plants and Their Uses, Department of Plant Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois, Urbana, Illinois 61801, USA. 217-333-7577. seigler@life.uiuc.edu.