Carbon fiber is a super strong material that is extremely lightweight. It is five times as strong as steel, two times as stiff, yet weighs about two-thirds less. Carbon fiber is basically very thin strands of carbon (even thinner than human hair). The strands can be twisted together, like yarn and then be woven together, like cloth. To make carbon fiber take on a permanent shape, it can be laid over a mold and coated with a stiff resin or plastic. Carbon fiber can also be defined as a fiber containing at least 92 wt % carbons.
Carbon fibers are a new breed of high-strength fiber. It came into existence in 1879 when Edison took out a patent for the manufacture of carbon filaments suitable for use in electric lamps. However, in the early 1960s, when there was a need f of the aerospace industry – especially for military aircraft – for better and lightweight materials, successful commercial production started.
In recent decades, carbon fibers have found wide usage in aeronautics, athletic performance, automobiles, building structures and, of course, musical instruments. Carbon fibers are used in composites with a lightweight matrix.
Carbon fiber composites are ideally suited for applications where strength, stiffness, lower weight, and outstanding fatigue characteristics are critical. They are used in the occasion where high temperature, chemical inertness, and high damping are important. They have been extensively used in composites in the form of woven textiles, prepregs, continuous fibers/roving, and chopped fibers. The composite parts can be produced through filament winding, tape winding, protrusion, compression molding, vacuum bagging, liquid molding, and injection molding.
There are two most important precursors in the carbon fiber industry are polyacrylonitrile (PAN) and mesophase pitch (MP). The structure and composition of the precursor affect the properties of the resultant carbon fibers significantly. Although the essential processes for carbon fiber production are similar, different precursors require different processing conditions in order to achieve improved Performance.
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Examples of Application
Aerospace – flights, rockets, satellites
Environment and Energy-related – wind power blade, tube power tank, battery charging flywheel, fuel cell, tidal power blade, the electric cable core
Auto-mobile – hood, roof, propeller shaft, body panel for the bus, compressed natural gas tank
Industrial use- the body of trains, x-ray top panel, pc housing, robot hand for liquid crystal panel, bridge pier reinforcement
Sports material – fishing rod, bicycle, hockey stick, racket, golf shaft.
Benefits of Carbon fiber
The potentially low-cost carbon fiber composites will be in a position to provide enormous advantages to a number of technologies for current and future everyday life applications, including a number of advanced technologies that are not currently commercially feasible. Lightweight components for automobiles, buses, trains, aircraft, ships, and applications including lightweight panels and load-bearing structures could result in weight savings, leading to a major saving in the nation’s and world’s energy consumption.
Low-cost carbon fiber is a national goal towards accomplishing a number of manufacturing technological breakthroughs.
Difficulties of Carbon Fiber
Cost is the main hurdle carbon fiber will have to overcome before it can provide a viable energy solution.
The second hurdle is waste disposal. When a typical car breaks down, its steel can be melted and used to construct another car (or building, or anything else made of steel). Carbon fiber can’t be melted down, and it’s not easy to recycle. When it is recycled, the recycled carbon fiber isn’t as strong as it was before recycling.
Lack of high-speed composite fabrication techniques
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Classification and types of carbon fiber
Based on modulus, strength, and final heat treatment temperature, carbon fibers can be classified into the following categories:
Based on carbon fiber properties, carbon fibers can be grouped into:
Ultra-high-modulus, type UHM (modulus >450Gpa)
High-modulus, type HM (modulus between 350-450Gpa)
Intermediate-modulus, type IM (modulus between 200-350Gpa)
Low modulus and high-tensile, type HT (modulus < 100Gpa, tensile strength > 3.0Gpa)
Super high-tensile, type SHT (tensile strength > 4.5Gpa)
Based on precursor fiber materials, carbon fibers are classified into:
PAN-based carbon fibers
Pitch-based carbon fibers
Mesophase pitch-based carbon fibers
Isotropic pitch-based carbon fibers
Rayon-based carbon fibers
Gas-phase-grown carbon fibers
Based on final heat treatment temperature, carbon fibers are classified into:
Type-I, high-heat-treatment carbon fibers (HTT), where final heat treatment temperature should be above 2000°C and can be associated with high-modulus type fiber.
Type-II, intermediate-heat-treatment carbon fibers (IHT), where final heat treatment temperature should be around or above 1500?C and can be associated with high-strength type fiber.
Type-III, low-heat-treatment carbon fibers, where final heat treatment temperatures not greater than 1000?C. These are low modulus and low strength materials.
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Manufacturing of Carbon fibers
Carbon fiber is a super strong material that is extremely lightweight. Carbon fibers generally have excellent tensile properties, low densities, high thermal and chemical stabilities in the absence of oxidizing agents, good thermal and electrical conductivities, and excellent creep resistance. Therefore Carbon fiber is enabling advancement in aeronautics, athletic performance, automobiles, building structures and, of course, musical instruments.
Carbon fibers are manufactured by a controlled pyrolysis of stabilized precursor fibers. First Oxidization process is done wherein the stabilization of precursor fibers at about 200-400 °C in air is done. Then carbonization is done wherein these fibers which are stabilized and infusible are treated at a high temperature of about 1,000 °C in an inert atmosphere to remove hydrogen, oxygen, nitrogen, and other non-carbon elements.
Then graphitized is done on those carbonized fibers at an even higher temperature up to around 3,000 °C to achieve higher carbon content and higher Young’s modulus in the fiber direction. The properties of the resultant carbon/graphite fibers are affected by many factors such as crystallinity, crystalline distribution, molecular orientation, carbon content, and the number of defects. The resulting carbon fibers are then post-treated to improve their adhesion to composite matrices.
For more news, please pay attention to Yarn Fair.
Source: textileschool
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According to knitting fair, as of December, there were 69.12 million confirmed cases of the virus worldwide, 557,763 new cases, 1.57 million deaths, and 10,526 new cases. The number of countries with more than 100,000 confirmed cases worldwide has increased to 69.
1) China Textile City: The sales of various knitted suede fabrics increase, and the advantages of creative pattern fabrics appear
Recently, the suede fabrics mainly made of circular knitting in the China Textile City market are still active, and the sales of matching pattern fabrics are both large and small. The transactions of cotton and polyester varieties have interacted, and the daily sales have fluctuated and increased. Recently, the large circular knitting flannels in China textile city market have been sold smoothly, orders are partially active, demand has increased significantly, and the shortage of popular fancy varieties has occurred, and the prices of creative fabrics have continued to rise in different amounts. .
2) The market atmosphere is deserted, and polyester production and sales continue to decline
On December 9, the production and sales of polyester filaments continued to decline, at 3-4% (the production and sales range was 0-100%). The trading volume in the previous working day was 4-5% (0-120%). The production and sales in Jiangsu and Zhejiang are estimated to be about 40% (0-110%). A few days ago, polyester filament yarns have risen slightly, and downstream resistance is high and most of them have covered positions. The market has been deserted. On December 9, polyester staple fiber was the same general, and as of that day, the production and sales were about 50% (0-120%).
3) U.S. crude oil inventories surged unexpectedly, and oil prices continued to rise and fall for two consecutive days
Recently, EIA reported that US crude oil inventories unexpectedly surged by 1,500 barrels last week, which greatly exceeded market expectations and caused a severe drop in oil prices. However, the attack on oil wells in Iraq caused oil supply risks, and the optimistic vaccine prospects supported oil prices. The US and Burundi oil futures rose again to 1%, basically regaining the decline after the EIA data was released, stabilizing above the 45 mark. US WTI crude oil January futures closed down 8 cents, or 0.17%, to 45.2 US dollars per barrel; Brent crude oil February futures closed up 2 cents, or 0.04%, to 48.86 US dollars per barrel
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4) Exor said it will invest 80 million euros in Chinese luxury brands
Exor announced on December 9 that the company will invest about 80 million euros in Chinese luxury brand Shang Xia. After the capital increase, Exor will become the controlling shareholder of the company, but Hermès and its founder Jiang Qionger will remain the "important" shareholders of the company; the investment is expected to be completed before the end of the year, which will bring about 80 million euros to Hermès. Recurring income.
5) Japan’s clothing retail sales in September fell by 23.5% year-on-year and 2.4% month-on-month
Japan and the European Union released retail sales data of textiles and clothing in September. According to statistics from the Ministry of Trade and Industry of Japan, the retail sales of Japanese goods in September fell by 0.1% month-on-month and 8.7% year-on-year. Among them, the retail sales of textiles and apparel fell by 2.4% month-on-month and 23.5% year-on-year. According to Eurostat's retail sales data, EU retail sales fell 1.7% month-on-month in September, but rose 2.1% year-on-year. Among them, the retail sales of textiles, clothing and footwear fell by 6.3% month-on-month and 12.6% year-on-year.
6) At least 110 garment factories in Cambodia closed down, and more than 55,000 employees were unemployed
In the first nine months of this year, at least 110 garment factories in Cambodia closed down, causing more than 55,000 workers to lose their jobs, but union leaders worry that this number will be even higher. Ngoy Rith, Secretary of State of the Ministry of Labor and Vocational Training, said that as of early September, 111 factories in the apparel, footwear and travel goods industries had closed. He said the number of closures was equivalent to the first nine months of last year, when 110 factories were closed. These closures caused 55,174 jobs to lose their jobs. According to knitting fair, this lack of jobs has improved compared with the 53,226 layoffs in the same period last year.
Source: Global Textile Network
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Pashmina is another name for Cashmere is a downy undercoat of the Capra Hircus Laniger goats that mainly live in the Trans-Himalayan regions classified as speciality hair fibres which possess special qualities of fineness and lustre, which is used for making finest quality shawls and hijabs.
The History
Woven shawls in India have been worn as early as the Indus Valley Civilization. A famous example is the statue of a priest-king found at Mohenjo-Daro, who is draped in a shawl decorated with trefoil patterns.
The past of this super-luxurious wool resonates with the history of India itself, going back to the pre-Mughal time when the first details of this enticing fabric were documented. It is however believed that unstitched woollen wraps on the shoulders were already being used for warmth some 3500 years ago – roughly the age of “Mohenjo Daro” civilization. “Buddha”, along with his disciples, is also shown in elegant drapes in most of the depictions
Definition
Pashmina, a prince of the speciality hair fibre is one of the finest natural fibre. Encyclopedia of textiles (1980) defines speciality hair fibres as the rare animal fibres which possess special qualities of fineness and lustre. Pashmina is the down fibres or undercoat derived from domestic goat known as Capra hircus, which is native to India (Von Bergen, 1963). Pashmina can also be defined as the down (undercoat) fibre derived from Cashmere goats with a diameter of 15 microns or less (ASTM, D-123-59).
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Pashmina has derived its name from the Persian word “pashm“ meaning “soft gold“, the king of fibres (Anon, 2005). It is well known for its fineness, warmth, softness, desirable aesthetic value, elegance and timelessness in fashion. It is the most luxurious fibre which is much softer than superfine merino wool of the same diameter with the result it commands a much higher price. It has occupied a unique position among the fibres of animal origin because of its warmth, lightness, handle and its better ability to absorb dyes and moisture.
On an equal weight basis, it is having 3 times more insulating capacity as that of wool (Von Bergen, 1963). The term Pashmina is also known as Cashmere, Kashmir, Pashm, Tiflit, Tiftik, Tivit, Tibit based on the effect on fibre yield. There is an apparent variation in the fibre length of Pashmina from different body regions in case of both male and females. As Pashmina grows as the undercoat and acts as a protective mechanism in Pashmina goats, so the sub-zero winter temperature also has an effect on the growth of Pashmina fibres.
The Changthang Region and the Changra goats
The pristine beauty of the Changthang region in Ladakh is marred by the stench of death that hangs over it. In the past three months, thousands of Changra goats, whose cold-shielding wool—six times finer than a human hair—is used to weave the famed pashmina shawls, have died because of heavy snowfall.
News of sporadic deaths came in the first week of February from the inaccessible transit settlements of the nomadic Changpas who rear Changra goats. Before the information could reach the state headquarters in Srinagar, there were more deaths. As per the Ladakh Autonomous Hill Development Council (LAHDC), 25,000 Changra goats died in February and March, putting livelihoods of the Changpas at risk.
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Changthang is a remote plateau in south-eastern Ladakh, bordering China (see map). At an altitude ranging from 4,200 metres to 5,700, the region is a cold desert that receives little rain. The summer rain of four to five days supports small patches of pastures, dictating the delicate ecology-economy equation of the Changpas. The pastoralist community largely depends on livestock products for survival. Dairy products are converted into less perishable forms like butter and cheese, which are used during winters. The produce is also used as currency in the barter system practised in the region.
Changthang usually experiences five centimetres of snow during winters when the temperature dips to -30°C. But this year it received 121 cm of snowfall, which many claims is the worst in the past half a century. “This is unusual and has triggered the crisis,” says Monisha Ahmed, an anthropologist working in the region. According to residents and government officials in Leh, most of the goats have died due to starvation. There was very little rain last summer due to which there weren’t enough pastures. Adding to the woes, heavy snowfall cut off the region from the outside, causing a delay in fodder supply from the government. Whatever pastures that sprouted were buried under snow, making grazing impossible. Mostly young and the old goats have died. It is not the cold but the thick snow cover over pastures that killed them, says Nawang Tharchen, a resident of Rupshu valley and a Changpa.
For more news, please pay attention to Yarn Fair.
Source: textileschool
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