Sisal fiber
| Sisal fiber | |
|---|---|
|
|
| Fiber type | |
| origin |
Different agaves |
| properties | |
| Fiber length | Bundles of fibers 60-100 cm |
| Fiber diameter | 17–50 µm (cell), avg. 25 µm |
| density | 1.33 g / cm 3 |
| tensile strenght | 0.08-0.839 GPa |
| modulus of elasticity | 3-98 GPa |
| Elongation at break | 2.9-6.8% |
| Water absorption | 11% |
| Chemical resistance | not resistant to strong acids |
| Products | Ropes, ropes, cords, carpeting, dartboards |
As sisal (formerly sisal are called the fibers from the leaves of some agave, especially those of sisal ( Agave sisalana ). Sisal is a relatively new natural fiber, its use began in the 19th century and reached its peak in the early 20th. Century. Despite a decline in its use, it is still one of the world's most important natural fibers .
In addition to the sisal agave fibers mainly used, those from Agave letonae , Agave funkiana and Agave lecheguilla are also counted as sisal, but in contrast to the important hybrid variety H.11648 , they are of significantly less importance. Demarcate is sisal against the related also as fiber plants fourcroydes Agave , as Henequen is referred to, as well as cantala designated or Maguey, very similar fibers of Agave cantala and Agave americana . From Agave decipiens is spurious or false sisal obtained, these fibers are finer, shorter and weaker.
The name of the fiber comes from the Mexican port city of Sisal on the Yucatán Peninsula , from where the sisal fibers were originally exported.
properties
Sisal fibers are multicellular, straight fibers. The individual bundles contain between 100 and 200 cells. With an average length of 2.282 millimeters and a diameter of 20.32 micrometers, the individual cells are relatively short and thick and therefore cannot be spun (minimum length required: 25 millimeters). Therefore fiber bundles are processed. Their length depends on the length of the leaf and the conditions in which the fibers are obtained; it is usually between 50 and 120 millimeters, with an average of 90.84 millimeters.
The cellulose content of the fibers is between 55 and 65%, supplemented by 10 to 15% hemicellulose . The lignin content is between 10 and 20%, the pectin content between 2 and 4%. These values make sisal - typical of leaf fibers - harder and coarser than bast fibers .
Sisal is extremely tough (57.2 cN / Tex ) and tensile strength (1830.12 cN / Tex), but it is particularly characterized by its unusual rigidity compared to other fibers .
Treatment with sodium hydroxide can change certain properties of the sisal. Sodium hydroxide dissolves hemicellulose, pectin and water-soluble substances from the fiber bundles, if higher concentrations of sodium hydroxide are used, the microstructure of the fiber also changes. This treatment makes the fiber bundles finer and shorter and easier to spin, but at the same time their toughness is reduced. This is particularly desirable when preparing fiber-plastic composite materials with polyester in order to reduce the appearance of delamination and to improve the distribution of the fibers in the polyester matrix .
production
processing
harvest
The plants can usually be harvested once a year, but under favorable conditions up to three harvests a year are possible. The time of harvest in the year is arbitrary, which allows a high degree of flexibility in the selection of the harvest time. Around 13 of the 1.5 to 2 (rarely up to 3) meters long and 500 to 1500 g heavy leaves each form a ring around the trunk. Around 50 to 65 leaves, i.e. 4 to 5 rings, are harvested during one harvest.
The leaves are cut off at the base, the spiky tip is capped and the leaves are bundled before they are broken down into fibers .
Fiber recovery
The proportion of dry fibers in the total weight of the fresh leaves is 4 to 7%; in the fiber digestion they are separated from the actual leaf tissue. Nowadays this is usually done by machines, either stationary devices that are operated by up to 10 people, are particularly powerful and can process up to 200 tons of sheets per shift, or mobile machines that are operated by five to eight people and 10 Can process tons per shift. The latter are characterized by a higher degree of extraction, so fewer fibers are lost.
After the fibers have been broken up, the fibers are bundled and soaked in water for 8 to 12 hours to wash out pectin and chlorophyll ( roasting water ), then they are dried in the sun for 8 to 10 hours. In order to remove remaining parenchymal tissue and short fibers, the fibers are then combed out or knocked out by machine.
Quality classification
In the last step, the fibers are assessed according to their quality and classified accordingly. These classifications are based on characteristics such as color or roughness. The best qualities, for example the Brazilian "Superior", must be light creamy white, cleaned, fully matured, particularly resistant, soft and smooth and free from adhesions or production residues. In addition, the fibers are marked according to their length.
use
Sisal is classically used for the production of ropes , ropes, cords and coarse yarns, some of which are used as the starting material for carpets and handicrafts. Due to its high durability, scratching toys for cats are often covered with sisal rope. More recent areas of application are the use as a filler for mattresses or as geotextile and as a polishing agent for technical purposes. It is also used to make straw hats . The use of sisal as part of fiber-plastic composite materials is not yet beyond the research and testing stage; in Brazil , a composite material made of sisal and cement is also being tested, which is intended to replace asbestos in prefabricated components . The sisal fiber is also used to make dart boards. This means that the boards have a much longer lifespan than when using paper or cork , for example , as the holes close again after the dart arrows have been pulled out. Sisal is not suitable as a textile fiber.
Production numbers
In terms of tons, sisal is the fifth most important fiber plant in the world. In 2006, world production was around 428,000 tons. The main producing countries are Brazil with over half of world production (247,558 t), Tanzania (27,800 t), Mexico (26,636 t), Kenya (25,000 t), Colombia (21,445 t) and China (20,000 t).
The FAO summarizes all agave species as well as breeding crosses in statistics, but the production figures of the species apart from the sisal agave usually only amount to a few thousand tons (e.g. 2 to 3,000 tons in the case of Agave letonae ) or their fibers are used only for special purposes (the fibers of Agave funkiana and Agave lecheguilla are used exclusively for brush production).
| country | metric tons |
|---|---|
| Brazil | 247,558 |
| Tanzania | 27,800 |
| Mexico | 26,636 |
| Kenya | 25,000 |
| Colombia | 21,445 |
| China | 20,000 |
| Madagascar | 17,000 |
| Cuba | 11,730 |
| Haiti | 5,500 |
| Nicaragua | 4,350 |
| Philippines | 4,000 |
| Venezuela | 3,909 |
| Ecuador | 3,465 |
| El Salvador | 2,500 |
| Morocco | 2,200 |
| Total (including other countries) | 427.843 |
history
The sisal agave was domesticated by the natives before the Spanish conquered Central America , but it was not used as a fiber plant, but for the production of pulque . The plant spread in North America through the displacement of the natives.
The Spanish and Portuguese also exported the plants to other countries and continents, where they were used as ornamental plants in the 18th and early 19th centuries. The production of fibers from the plant did not begin until the 19th century, the main producing countries at that time were what is now Indonesia and the Philippines.
In 1893, the German botanist Richard Hindorf introduced bulbils from Florida to Tanzania, 62 plants formed the basis of East African sisal production. In 1903, Kenya also started growing. In the same year Horácio Urpia Júnior introduced the sisal agave to Brazil. It was only between 1937 and 1941, however, that the production of sisal began in Brazil in a commercially significant manner. Brazil began exporting sisal as early as 1946 and by 1951 it was the second largest producing country.
The Tanzanian research institute ARI Mlingano, founded especially for this purpose in 1934, first issued seedlings of the hybrid variety H.11648 at the end of the 1950s , which quickly led to Tanzania becoming the most successful sisal producer in the world. This cross of Agave angustifolia and Agave amaniensis was introduced in China in the 1960s and still dominates the population there today. In East Africa , the proportion of hybrids is still higher than that of the actual sisal agave. In the 1970s, they began to be grown in Brazil, but in the main growing areas of Bahia , Paraíba and Rio Grande do Norte , they only make up around 5% of the plants grown today.
From 1964 the market for sisal gradually collapsed due to the increasing competition from synthetic fibers, and production continued to decline. While the world production of sisal and henequen in the early 1970s was still almost 800,000 tons per year, it had fallen to 200,000 tons by the turn of the millennium. Originally important growing countries such as Tanzania, Mexico or Kenya reduced their production volumes by up to 80%. Only recently has the use of sisal increased again due to new applications and the rising prices for crude oil as a basis for synthetic fibers.
Individual evidence
- ↑ a b c d e f g Comparative physical, chemical and morphological characteristics of certain fibers. In: Franck 2005; Pp. 4-23.
- ↑ a b c d e f g h i C. Yu: Sisal. In: Robert Franck (Ed.): Bast and other plant fibers. Cambridge / Boca Raton, 2005, ISBN 1-85573-684-5 / ISBN 0-8493-2597-8 , pp. 229-273.
- ↑ cf. J.Merritt Matthews, Walter Anderau, HE Fierz-David, The textile fibers: their physical, chemical and microscopic properties, Berlin 1928, p. 653, reprint 2013 978-3-642-91077-7)
- ↑ Menachem Lewin (Ed.): Handbook of Fiber Chemistry. Third edition. Taylor & Francis Group, Boca Raton 2007, ISBN 978-0-8247-2565-5 , p. 460.
- ↑ a b c d O.RRF da Silva, FA Suinaga, WM Coutinho, WV Cartaxo: Cadeia Produtiva / Productive Chain. In: O Sisal do Brasil / Brazilian Sisal. Brasília 2006, pp. 33-45.
- ↑ AL Leao, AP Joaquim, H. Savastano, AF Leal, JW barbosa do Nascimento: Novos Usos / New Uses. In: O Sisal do Brasil / Brazilian Sisal. Brasília 2006, pp. 65-81.
- ↑ R. Koslowski, M. Rawluk, J. Barriga-Bedoya: Ramie. In: Robert Franck (Ed.): Bast and other plant fibers. Cambridge / Boca Raton, 2005, ISBN 1-85573-684-5 / ISBN 0-8493-2597-8 , p. 209.
- ↑ a b Information according to FAOSTAT, online .
- ↑ a b c d F. A. Suinaga, ORRF da Silva, WM Coutinho: A História / History In: O Sisal do Brasil / Brazilian Sisal. Brasília 2006, pp. 16-22.
- ↑ Information page on ARI Mlingano on the website of the Tanzanian Ministry of Agriculture, Food & Cooperatives , online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. .
- ↑ George Sembony: Mlingano institute needs USD1.1m for research , May 12, 2007, IPPMedia.com, online ( Memento of the original of December 2, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ ESC Consultation No. 5: Sisal Production And Marketing In China: Retrospect And Prospect. Consultation On Natural Fibers, Rome, December 12-14, 2000, online (PDF).
- ^ B. Moir, Sietse van der Werff: Visao Mundial / Global Perspective In: O Sisal do Brasil / Brazilian Sisal. Brasília, 2006, pp. 113-125.
- ↑ C. Yu: Sisal. Tab.6.10, p. 241.
Web links
- Sisal fibers on materialarchiv.ch, accessed on June 28, 2017.