Stinging Nettle - Free Essay Example

[pic] Stinging nettle In the hunt for new, ecologically friendly fabrics stinging nettle fiber has come up smelling of roses. Clothing made from the nettle is not a new idea; for the past 2,000 years people have worn fabrics made from these stinging plants. But nettle lose there popularity when cotton arrived at 16th century, because cotton was easier to harvest and spin. Nettles made a brief come back during the First World War, Germany suffered storage of cotton and nettles were used to produce Germany army uniforms. Now, new advance in spinning technologies and cross- breeding to produce super- high- fiber plants means that stinging nettles are set to become the latest fashion. Nettle Nettle is highly successful plant found all over the temperate areas of the world. Nettle is common herbaceous plant which regroups 30 to 45 species. It is the part of the urticaceae family such as ramie (Asian nettle, Boehmeria nivea) and belongs to the genus Urtica. The most prominent member of the genus is the stinging nettle Urtica dioica, native to Europe, North Africa Asia and North America. Existing the problems in the agriculture sector underline need for alterative crops. Stinging nettle is a perennial plant thrives in nitrogenous and Over-fair-sized soil and also has environmentally sound cultivation method as well as resistance to diseases and rests so they do not need dangerous pollutants to protect them. The plant itself is variable growing from 0. 6sto 2 meters plus in height and can be found in variety of habitats and soil types the stem specially of old plant of the big stinging nettle has very long and tough bast fibers. Thousands of year ago nettle thread – also called nettle fiber was produced from this plant. Further more fibers also useful for manufacture of nettle cloth, which is tougher than linen, as wall as finishing nets and rope. The single fiber of the stinging nettle can only reach the maximum of 250 millimeters could be reached. Net tle plants widely exist in china, but up to now there is no research regarding the Chinese nettle fiber properties it’s specially about there spinability. The average length of the nettle fiber is about 34mm, and fineness is ranging from 0. 589 to 0. 769 Tex. Nettle fiber has high breaking strength and low breaking extension and high initial young modulus. Both biochemical method and chemical method can meet the requirement of nettle degumming, with residual being less than 4. Nettle fiber can be utilized as textile material can be spun in rotor spinning machine after well degumming. Nettle fiber invention The first attempt to commercialized the production of nettle fiber was in Germany during 1720s, since there have been frequent effort in several European countries to cultivate the nettle and develop method of extracting the fiber that could be applied on large scale. Most of these results carry in Germany particularly during the 19th century. Unfortunately they do no t seem to have been successful, cost effective method of nettle fiber extraction resulting from all this activity. It was Dr Gastav bredemann who turned the tide with his research from 1927 to 1950. He interbred selected plant of Urtica dioica and produced several high fiber clones that could be cultivated. The criteria for selected plants were that they should be frost resistant, have long straight stems with the minimal branching and of course a high percentage fiber in stem. These verities were given the name ‘Nettle’. Bredemann’s work was quickly forgotten for many years after his book DIE GROBE BRENNESSEL was published in1950. During the 1990s Dr Jens dreyer from the institute of applied Botany in H Hamburg re-identified the individual fiber nettle clones that still survived in the institute and revived and tested Bredemann’s research. The fiber nettle is now being used as a basis for several commercial nettle fiber projects in Europe and advance i n technology are making it possible to process the nettle more successfully and cost effectively. The use of the wild nettle for fiber is still also possible. The Kalajokilaakso nettle fiber project in Finland has demonstrated this by producing a nettle fiber yarn from wild nettle that have been carefully selected and cultivated. Chemical and physical properties Research into the chemical and physical properties of nettle fiber has been taking place for the last five years. All the available information has been gathered together from projects in Finland, England and Germany and where possible a comparison has been made between the wild nettle and cloned fiber nettle. Fiber nettle can be distinguished from wild nettle by their larger quantity of individual fiber cells with the bigger walls. The plants was selected because their lack of branching from the stem they have only a few stinging hairs will lose most of there leaves in august which gives a fewer problem of biomass in the straw. Most work on the characteristics of fiber has been done by the Faserinstitut Bremen. The individual fiber cell are composed of cellulose and held together in their groups by pectin and hemicelluloses. The shape of the cell oval to round polygonal. The oldest and thickest fiber is in outer part of the bark. The length and diameter of long fiber is influenced by the species of nettle, its level of maturity and nutrition, where is found on the plant and the method of extraction. After mechanical separation the average measurement of the length is 4-7cm and 40-50 µm in diameter. Treatment by alkali or enzymes leads to 40% fiber measuring 4-5cm long and 25% measuring 5-6cm long, when the fiber length distribution by mass is calculated. Their fineness is approximately 15-25  µm in diameter. The pure fiber content of the best cultivated nettle plants from Hamburg is about 155 of dry mass; therefore six tones of harvested dry steam would give an average yield of approxi mately 900 kg of fine fiber. The wild nettle is approximately 3-8% of dry mass. Fiber from nettle kwon as nettle wool due to its softness and the nature colour is cream/ white, so it is easy to apply a coloured dye to the fiber or fabric. The degree of polymerization of cellulose in the cell wall is about 2280. Nettle is strong fiber with 50cN/t, measured by the stelometer and this is important in spinning. The fiber is separated with mechanically and then with enzymes to get strengths of 23-35cN/tex in comparison to cotton fiber has strength is 20Cn/tex, but fiber is not flexible which affect spinning process. The elasticity module is much higher than banana and jute. Moisture absorption is about 11%. The fibers contain about 54% pure cellulose 10%arabinane, xylane galacturonane and other hemicelluloses. Nettle fibers contain 4% pectin. This is an important factor has to removed from the fiber to get the good and fine yarn. This removed in method of enzymatic retting. By usi ng pectinases the pectin can be broken down thus freeing the individual fibers. |Parameter |Before retting |After retting | |Fiber strength (N/mm? |740 | | |Fiber strength (cN/tex) |50 |25-35 | |Fineness (dtex) |5 | | |Elasticity modulus (Gpa) |34. | | |Strain (%) |12 | | |Cell wall density (g/cm) |1. 1 | | |Length of fiber (mm) |40-50 | | |Cellulose (%) |54 |88 | |Hemi cellulose (%) |10 |4 | |Pectin (%) |4. 1 |0. 6 | |Lignin (%) |9. 4 |5. 4 | |Wax and fats (%) |4. 2 |3. 1 | |Water soluble products (%) |18 |2. | (Retting is treatment of enzyme to improve its properties) [pic] Nettle fiber possess extra ordinary extraordinary characteristics and properties †¢ It is very tough and is able to absorb greater deal of moisture, swell like cotton and splendor. †¢ The fiber of the stinging nettle have a special characteristic in the fact that they are hollow which means they can accumulate air inside thus creating natural insulation. To create cool fiber in summer the yarn length are twisted closing the hollow core and reducing insulation. In winter with low twist the hollow fiber remains a constant temperature. The average tensile properties of nettle are young modulus equal to 87 Gpa, a tensile strength equal to 1594 Mpa and, a strain at failure is equal to 2. 11% As from table stinging nettle fiber have a higher stiffness but lower strength and strain to failure then glass fibers. |Table 1: mechanical properties of nettle | Fiber |Young’s modulus (Gpa) |Strain to failure (Mpa) |Ultimate stress (%) |Density(g/m? ) |Average diameter (micrometer) | |Stinging nettle |87 |2. 2 |1594 |Na |20. 0 | |Flax |58 |3. 3 |1339 |1. 53 |23. 0 | |Hemp |35 |1. 6 |389 to 900 |1. 07 |31. 2 | |Ramie |20 to128 |1. 2 to 3. 8 |400to 1000 |1. 56 |50. 0 | |Sisal |9 to21 |3 to 7 |350 to 70 |1. 45 |100to300 | |Glass |72 |3. 0 |2200 |2. 54 |5to25 | | What is in the sting? The stinging structure of the nettle is very similar to the hypodermic needle although it predates that man-made invention by million of years! Each sting is actually a hollow hair stiffened by silica with a swollen base that contains the venom. The tip of this hair is very brittle and when brushed against, no matter how lightly, I t breaks off exposing a sharp point that penetrates the skin and deliver its stinging payload. It is used to be a thought that the main constitute of the sting was formic acid – the chemical used by ants, burning sensation that demands to be scratched. Although formic acid is present in the sting, recent research has shown that the main chemical is histamine, acetylcholine and 5-hyroxytryptamine. Processing of the nettle fiber by traditional method Step1:- There are considering being a number of benefits associated with the cultivation of nettles. The nettle is a perennial and can be harvested year after year without replanting. Research has shown that nettle may be propagated by various method ; seed, seedling, cutting, and planting of rhizome pi eces the advantages of growing by seed is that is a economical . The nettle plant is depending upon good water supply. Nettle needs good soil condition with sufficient supply of nitrogen and pH of 6. 5. The seedling can be planted in May with a vegetable plant when they have reached 5-6 week growth. The fiber nettle is propagated by stem cutting. The cutting required 4-8 week. The nettle rhizomes are than protected within the rigid from damage by machine. Step 2:- The shrubs are brought and the men strip them of their bark and dried for 3-4 days Step3:- The dried nettle bark is boiled with ash for 2-3 hours. Step4:- Stone washed near by river is done Step5:- Then the fiber is mixed with limestone and dried for another 2-3 days. Step6;- After this they separate the fiber from limestone and processed into threads with the help of a traditional spinner or through spinning wheel. Step:-7 Cloths are traditionally woven in handlooms. Now days, a By comparison between the flax, hemp, ramie although the nettle stem are irregular in their size and the fiber are prone to break at the point where the stem branches. The new technology of spinning nettle fiber is not research till yet. The traditional view of nettle fiber cloth was that it was soft, hardwearing and warm to skin. The nettle fiber is mixed with other fiber like cotton, silk, viscose and flax up to 80% nettle fiber has been used in the some of blends. The fibers have been processed by retting with enzymes and selected microbes. The retting process is not only separate s the fiber from the plant stem, but also break down many of the fiber groups into single fiber cells or ultimate fibers. The nettle fiber extracted in the finish project were form into yarn first putting them through [pic]