: Mineral Resources, Why I hated Geography at school, Energy Resources, Universe, Structure of the Earth, Earth Layers, Earth Composition, Tectonics, Human Geography, Geomorphology, Oceanography, Cartography, History, Landforms, Climatology, Soils, Vegetation, Regions, Population, Resources, Industries|
Agricultural types and their distribution, Barley, Cocoa production, Cocoa, Progress of World's Coffee Industry, Coffee, Commercial Agriculture, Maize or Corn, Cotton areas, Cotton, Dairy Australia, Dairy Europe, Dairy Industry, Dairy Farming, Fishery, Fishing areas, Fishing areas 2, Fishing economy, Flax, Conifer Forests, Conifer Forests 2, Forest Growth, Temperate Forests, Forest Types, Forestry, Gathering in Tropical Forests, Hemp, Irrigation Regions, Irrigation, Jute, Leather, Linseed & castor oils, Livestock ranching, Livestock, Lumbering in the Temperate Forests, Lumbering in the Temperate Forests 2, Lumbering in Tropical Forests, Meat, Mediterranean Agriculture, Mid-Latitude Agriculture, Millets and Sorghums, Mixed Farming, Monsoonal Agriculture, Nylon, Oats, Oil crops, Pastoral Farming or Pastoralists, Plantation, Wood Pulp and Paper, Rayon, Rice, Rubber, Rye, Sedentary Primitive Agriculture, Silk Europe, Silk India, Silk, Sisal, Soybean oil, Sugar, Sugarcane in India, Sugarcane, Tea Areas, Tea Trade, Tea, Tobacco areas, Tobacco, Tropical Fishing, Vegetables & fruits, Wheat regions, Wheat types, Wheat, Wool Production Areas, Wool Production, World Rice|
Sisal is also an example of leaf fibre. The fibres are used for binder and baler twine and other cords. It is cheaper than Manila hemp. Brazil and Tanzania produced 50 per cent and 20 per cent respectively of world's output of sisal in 1987-88.
The fibre comes from xerophylous plants, which grow well in areas having dry conditions and rocky or dry loamy soils. The 76-100 cm of rainfall and high temperature are necessary for the plant. The plant is slow growing and takes four to five years so as to be available for harvest.
Most of the commercial crop is grown on plantations where fibre is separated from the plant by machinery. The fibre thus obtained is dried, tied into bales and exported. The Yucatan peninsula in tropical North America,
Tanzania, Brazil, Kenya, Angola, Haiti and Indonesia are the main producers of sisal. In Yucatan the production is done on a commercial scale around Merida. The port Progreso handles sisal fibre for export.
The introduction of rayon in the field of textiles signifies a tremendous and amazing contribution of science. It was first obtained by Count Chardonnet of France in 1884. In French Jura the first rayon plant was set up and gradually it spread to other west European countries, U.S.A. and Japan.
The manufacturing of rayon involves intricate chemical process, engineering skill and large capital outlay. As such the countries of rayon manufacture are few. Germany, U.S.A. and Japan were the leading producers of rayon. The raw materials needed for rayon manufacture is wood pulp of spruce and pines mainly. Chemicals like carbon bisulphide, acetic acid and ether are essential.
There are four methods of rayon production-
(i) the Viscose; (ii) the Cellulose acetate; (iii) Cupra-ammonium; and (iv) the Nitro-cellulose.
In each of them, pure cellulose of wood pulp or cotton linters is treated by a chemical solvent to produce a viscous mass, which is forced through very thin holes to coagulate into filaments either by drying as in nitrocellulose and cellulose-acetate processes or by passage through a fixed solution as in cupra-ammonium and Viscose processes.
The filaments are then twisted together to make yarn used for weaving.
Of all the processes of rayon manufacture, the Viscose process is the most important process. Viscose rayon, which is made of wood pulp, is the principal type manufactured. The acetate rayon is made of cotton linters and holds second place. The acetate rayon textiles are waterproof and are costlier than Viscose rayon. The Cupra-ammonium process gives yam of lustrous variety. From the two basic materials, wood pulp and cotton linters, fabrics of various types and qualities are manufactured for clothing, draperies and upholstery.
Next: Soybean oil