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| | Ramie is one of the strongest natural fibers. It exhibits even greater strength when wet. Ramie fiber is known especially for its ability to hold shape, reduce wrinkling, and introduce a silky lustre to the fabric appearance. It is not as durable as other fibers, and so is usually used as a blend with other fibers such as cotton or wool. It is similar to flax in absorbency, density and microscopic appearance. However it will not dye as well as cotton. Because of its high molecular crystallinity, ramie is stiff and brittle and will break if folded repeatedly in the same place; it lacks resiliency and is low in elasticity and elongation potential.[3] | | | | Physical and chemical properties of ramie fiber | | Cellulose (wt%) | Lignin (wt%) | Hemicellulose (wt%) | Pectin (wt%) | Wax (wt%) | Microfibrillar angle (°) | Moisture content (wt%) | Density (mg/m3) | | 68.6 - 76.2 | 0.6 - 0.7 | 13.1 - 16.7 | 1.9 | 0.3 | 7.5 | 8.0 | 1.50 | | Source: [4] |
| | | | Mechanical properties of untreated ramie fibers | | Fiber diameter (mm) | Fracture load (N) | Tensile strength (MPa) | Fracture strain (%) | | 0.034 | 0.467 | 560 | 0.025 | | Source: [5] |
| | | | Uses | Despite its strength, ramie has had limited acceptance for textile use. The fiber's extraction and cleaning are expensive, chiefly because of the several steps-involving scraping, pounding, heating, washing, or exposure to chemicals. Some or all are needed to separate the raw fiber from the adhesive gums or resins in which it is ensheathed. Spinning the fiber is made difficult by its brittle quality and low elasticity; and weaving is complicated by the hairy surface of the yarn, resulting from lack of cohesion between the fibers. The greater utilization of ramie depends upon the development of improved processing methods.
Ramie is used to make such products as industrial sewing thread, packing materials, fishing nets, and filter cloths. It is also made into fabrics for household furnishings (upholstery, canvas) and clothing, frequently in blends with other textile fibers (for instance when used in admixture with wool, shrinkage is reported to be greatly reduced when compared with pure wool.) Shorter fibres and waste are used in paper manufacture.
Ramie is also used as an ornamental plant in eastern Asia.
Ramie (Boehmeria nivea), commonly known as China grass, white ramie, green ramie and rhea, is one of the group referred to as the bast fiber crops. It is a hardy perennial belonging to the Urticaceae or Nettle family, which can be harvested up to 6 times a year. It produces a large number of unbranched stems from underground rhizomes and has a crop life from 6 to 20 years. The bark contains gums and pectins causing the fibers to be useable only after chemical treatment. | | | The true ramie or 'China Grass' is also known as 'white ramie' and is the Chinese cultivated plant. It has large heart shaped, crenate leaves covered on the underside with white hairs that give it a silvery appearance. Boehmeria nivea var. tenacissima, is known as 'green ramie' or 'rhea'. It is believed to have originated in the Malay Peninsula. It has smaller leaves which are green on the underside, and is better suited to tropical climates.
| Ramie is one of the oldest textile fibers. It was used in mummy cloths in Egypt during the period 5000 - 3000 BC, and has been grown in China for many centuries. The main producers of ramie today are China, Brazil, Philippines, India, South Korea and Thailand. Only a small percentage of the ramie produced is available on the international market. Japan, Germany, France and the UK are the main importers, the remaining supply is used domestically (in the country in which it is produced).
Ramie fiber is very durable, is pure white in colour and has a silky luster. It is reported to have a tensile strength eight times that of cotton and seven times greater than silk. However, other reports claim that the tensile strengths of cotton, flax, hemp and ramie are similar. These discrepancies can be partly attributed to the effects of source of supply, method of processing, the test conditions, temperature and humidity, on the fiber strength.
The stems of ramie grow to a height of 1 - 2.5 meters. The most suitable climate for ramie is one which is warm and humid, with an annual rainfall of at least 1000 mm. Well established plants can tolerate drought and frost, but grow better without. As ramie productivity is high it can rapidly deplete the soil of nutrients. |
| | | | Properties | | Advantages of Ramie as a Fabric : | | | | Resistant to bacteria, mildew, alkalis, rotting, light, insect attack. | | | | Extremely absorbent and therefore comfortable to wear, especially during warm weather. | | | | Has natural stain resisting ability with ease of stain/soil removal similar to that of linen (and this is better than cotton). | | | | Not harmed by mild acids. | | | | Dyes fairly easily. | | | | Good wet-fastness in laundering - though dark colors may lose their vibrancy over repeated launderings. | | | | Increases in strength when wet. | | | | Withstands high water temperatures during laundering. | | | | Smooth lustrous appearance improves with washing. | | | | Keeps its shape and does not shrink. | | | | Can be bleached. | | | | | | Disadvantages of Ramie as a Fabric : | | | | Low in elasticity. | | | | | Low abrasion resistance. | | | | Wrinkles easily (but application of wrinkle-resistant finishes or blending with synthetic fibers can reduce the problem in woven fabrics). | | | | Stiff and brittle. | | | | The fiber is high cost which reduces its competitiveness against other textile fibers - this high cost is due to high labor requirement for production, harvesting and decortication. | | | | There is a need to de-gum the fiber prior to processing. | | | | |
| | | | Applications | | | | Apparel. | | | | dresses, suits, skirts, jackets, pants, blouses, shirts, children wear, mixed with cotton in knitted sweaters. | | | | Home Fashion. | | | | curtains, draperies, upholstery, bedspreads, table linens, sheets, dish towels. | | | | Sewing thread. | | | | Handkerchiefs. | | | | Parachute fabrics. | | | | Woven fire hoses. | | | | Narrow weaving. | | | | Canvas. | | | | Filter cloth. | | | | When used in a mixture with wool, shrinkage is reported to be greatly reduced when compared with pure wool. | | | | Short waste fibers are used for the production of high quality papers, such as bank notes & cigarette papers. | | | | As ramie takes up phosphorous, it is potentially useful for cleaning up the Everglades. This region suffers from a nutrient overload from the sugar industry. | | | | |
| | Ramie as a Blend | | | Ramie is most often blended (common is 55% ramie/45% cotton) with other fibers for its unique strength and absorbency, luster and dye-affinity. When blended with high-quality cotton it offers increased luster, strength and color.
When mixed with wool, ramie adds lightness and minimizes shrinkage. When blended with rayon, it offsets the low wet strength.
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| | Care Recommendations for Ramie Fabrics | | | | | Care procedures prescribed on the care labels of ramie products vary. Items of 100 percent ramie should not require special care. Generally, they may be laundered or dry-cleaned depending on individual dyes, finishes and design applications.
High temperatures will not harm the fiber itself, making washing in hot water and ironing at high settings possible; however, color retention, shrinkage control or properties of blended fibers may dictate lower temperatures.
| Recent laboratory testing done has led to the conclusion that the best performance results when gentler or more special handling is used in care. For example, fabrics retained the best color and shape with the most wrinkle-free appearance when they were dry-cleaned.
Machine washing in cold water on gentle cycle with line drying was better than machine washing in warm water with tumble drying on permanent press cool down cycle.
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| | | Hand washing in cool water with flat drying is the most strongly recommended home care method for both knits and woven fabrics. The consumer who knows the strengths and limitations of the fiber can receive maximum service and enjoyment from ramie products.
When storing ramie or ramie blends, lay them flat. Ramie fibers are brittle and tend to break.
Avoid folding the garment or pressing sharp creases in woven fabrics.
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| | | | Ramie's role in farming systems : |
| The following characteristics of the ramie crop would influence its suitability in Australian farming systems:
| | | | It is a perennial crop with a life of 6 to 20 years. | | | | It is capable of producing high yields of biomass and if the harvesting system involves total removal of this biomass, there would be a rapid decline in soil fertility and | | | | Ramie is subject to a number of pests and diseases, including nematodes. |
| | | | Grades | | | | Fibers | | | | | Tow/Tops | | | | Spun yarns | | | | | | | | |
| | | | | | Processability | | The crop | Ramie is a member of the Urticaceae or nettle family and is a hardy perennial which produces a large number of unbranched stems from underground rhizomes.
The stems of ramie grow to a height of 1 to 2.5 m. The crop is generally propagated vegetatively, using rhizome or stem cuttings. Production begins to decline once roots become overcrowded. | | |
| | | | Harvesting | Ramie is normally harvested two to three times per year but under good growing conditions can be harvested up to six times per year. Harvesting is done just before or soon after the onset of flowering, since there is a decline in plant growth at this stage and maximum fiber content is achieved. Stems are harvested by cutting just above the lateral roots or the stem can be bent, to enable the core to be broken and the cortex can be stripped from the plant in situ. Mechanical harvesters have been developed but are not used commercially. After harvesting, stems are decorticated while the plants are fresh as the bark gets harder to remove as the plant dries out. The bark ribbons are dried as quickly as possible to prevent attack by bacteria or fungi.
The dry weight of harvested stem from both tropical and temperate crops ranges from about 3.4 to 4.5 t/ha/year; a 4.5 ton crop yields about 1,600 kg/ha/year of dry non-de-gummed fiber. The weight loss during de-gumming can be up to 25% giving a yield of de-gummed fiber of about 1,200 kg/ha/year. | | | | Extraction of fiber | | Extraction of the fiber occurs in three stages. | | | | Firstly, the cortex or bark is removed, either by hand or machine, in a process called de-cortication. | | | | The second stage involves scraping the cortex to remove most of the outer bark, the parenchyma in the bast layer and some of the gums and pectins. | | | | The third stage involves washing, drying and de-gumming of the residual cortex material to extract the spinnable fiber. Details of the de-gumming processes tend to be regarded as commercial-in-confidence information |
| | | | Ramie fiber | Ramie fiber is one of the premium vegetable fibers. The ultimate fibers are exceptionally long and are claimed to be the longest of vegetable origin, with one report claiming the fibers range up to 580 mm, averaging about 125 mm.
Ramie fiber is very durable, is pure white in colour and has a silky luster.
For the hand spinner, ramie is treated similar to flax in that it can be either wet or dry spun. A wet spun yarn will produce a smooth softer yarn with high luster, while a dry spun yarn will feel hairier, have less luster and a harsher handle. It can readily be blended with other fibers such as wool or silk, although the length of ramie can sometimes cause difficulties. | | | | |
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