User:Natural fibre

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Sisal is an agave Agave sisalana that yields a stiff fiber traditionally used in making twine and rope. (The term may refer either to the plant or the fiber, depending on context.) It is has sometimes been incorrectly referred to as sisal hemp because hemp was for centuries a major source for fiber, so other fibers were sometimes named after it.

The plant originated in the Yucatan Peninsula of Mexico. In the 19th century, sisal cultivation spread  to Florida, the Caribbean islands and Brazil, as well as to countries in Africa, notably Tanzania and Kenya, and Asia. The first commercial plantings in Brazil were made in the late 1930’s and the first sisal fiber exports from there were made in 1948. It was not until the 1960‘s that Brazilian production really accelerated and the first of many spinning mills were established. Today Brazil is the major world producer of sisal.

According to www.advancedbuildings.org, sisal farming initially caused great environmental degradation, because sisal plantations replaced native forests, but is still considered less damaging than most. No pesticides or chemical fertilizers are used in sisal production, and although herbicides are occasionally used, even this impact may be eliminated, since most weeding is done by hand.

The Sisal Plant
Sisal plants consist of a rosette of sword-shaped leaves about 1.5 to 2 meters tall. Young leaves may have a few minute teeth along their margins, but lose them as they mature. Sisals are sterile hybrids of uncertain origin; although shipped from the port of Sisal in Yucatán (thus the name), they do not actually grow in Yucatán, the plantations there cultivate henequen (Agave fourcroydes) instead. Evidence of an indigenous cottage industry in Chiapas suggests it as the original location, possibly as a cross of Agave angustifolia and Agave kewensis.

Propogation of sisal is generally by using bulbils produced from buds in the flower stalk or by suckers growing around the base of the plant. These methods offer no potential for genetic improvement. Invitro multiplication of selected genetic material using meristematic tissue culture (MST) offers considerable potential for the development of improved genetic material.

The sisal plant has a 7-10 year life-span and typically produces 200-250 commercially usable leaves. Each leaf contains an average of around 1000 fibers. The fibers account for only about 4% of the plant by weight. Sisal is considered a plant of the tropics and subtropics, since production benefits from temperatures above 25 degrees Celsius and sunshine.

Extracting the fibre
Fibre is extracted by a process known as decortication, where leaves are crushed and beaten by a rotating wheel set with blunt knives, so that only fibers remain. In East Africa, where production is typically on large estates, the leaves are transported to a central decortication plant, where water is used to wash away the waste parts of the leaf. The fiber is then dried, brushed and baled for export. Superior quality sisal is found in East Africa, once washed and decorticated. Proper drying is important as fiber quality depends largely on moisture content. Artificial drying has been found to result in generally better grades of fiber than sun drying, but is not feasible in the developing countries where sisal is produced. In the dryer climate of north-east Brazil, sisal is mainly grown by smallholders and the fiber is extracted by teams using portable raspadors which do not use water. Fibre is subsequently cleaned by brushing. Dry fibers are machine combed and sorted into various grades, largely on the basis of the previous in-field separation of leaves into size groups.



Uses of Sisal
Traditionally, sisal has been the leading material for agricultural twine (binder twine and baler twine) because of its strength, durability, ability to stretch, affinity for certain dyestuffs, and resistance to deterioration in saltwater. but the importance of this traditional use is diminishing with competition from polypropylene and the development of other haymaking techniques, while new higher-valued sisal products have been developed. Apart from ropes, twines and general cordage sisal is used in low-cost and specialty paper, dartboards, buffing cloth, filters, geotextiles, mattresses, carpets, handicrafts, wire rope cores and Macrame. In recent years sisal has been utilized as an environmentally friendly strengthening agent to replace asbestos and fiberglass in composite materials in various uses including the automobile industry. . The lower grade fiber is processed by the paper industry because of its high content of cellulose and hemicelluloses. The medium grade fiber is used in the cordage industry for making: ropes, baler and binders twine. Ropes and twines are widely employed for marine, agricultural, and general industrial use. The higher-grade fiber after treatment is converted into yarns and used by the carpet industry.

Other products developed from sisal fiber include spa products, cat scratching posts, lumbar support belts, rugs, slippers, cloths and disc buffers. Sisal wall covering meets the abrasion and tearing resistance standards of the American Society for Testing and Materials and of the National Fire Protection Association.

Despite the yarn durability sisal is known for, slight matting of sisal carpeting may occur in high traffic areas. Sisal carpet does not build up static nor does it trap dust, so vacuuming is the only maintenance required. High spill areas should be treated with a fiber sealer and for spot removal, a dry cleaning powder is recommended. Depending on climatic conditions, sisal will absorb air humidity or release it causing expansion or contraction. Sisal is not recommended for areas that receive wet spills, or rain or snow. Sisal is used by itself in carpets or in blends with wool and acrylic for a softer hand.

As extraction of fibre uses only a small percentage of the plant, some attempts to improve economic viability have focussed on utilising the waste material for production of biogas, for stockfeed, or by the extraction of pharmaceutical materials.

Global Production and Trade Patterns
Global production of sisal fibre in 2007 amounted to 240 thousand tonnes of which Brazil, the largest producing country, produced 113,000 tonnes.

Tanzania produced approximately 37,000 tons, Kenya produced 27,600 tonnes, Venezuala 10,500 tonnes and 9,000 tonnes were produced in Madagascar. China contributed 40,000 tons with smaller amounts coming from South Africa, Mozambique, Haiti, and Cuba. Sisal occupies 6th place among fiber plants, representing 2% of the world’s production of plant fibers (plant fibers provide 65% of the world’s fibers).

As one of the world's important natural fibres, sisal is covered by activities of the International Year of Natural Fibres 2009.

Heraldry
The sisal plant appears in the arms of Barquisimeto, Venezuela.