This article Knitting fair introduces a modified form of polyamide Nylon to you. Aramid fibre is an innovation and modified form of polyamide Nylon. Further innovations were carried out to develop a fibre which can have enormous advantages over nylon fibres and possess unique properties such as ultra-high strength, rigid & highly oriented molecular structure, lightweight, low flammability, resistance to abrasion & organic solvents, etc. The Aramid fibres were developed which means Ar—-Aromatic, and amid—Amides.
Two aromatic rings are attached to Amide linkages and are called aromatic polyamides. These are classified in two forms with their trade names Nomex (meta-aramid) and Kevlar (para-aramid). These two are most common. The other names are Twaron, technora, Heracron, etc. They are modified forms of polyamides (Nylon, Polyester)
ARAMID is a synthetic fibre that is produced by spinning a solid fibre from solution. The initial preparation of the polymer is generally achieved by a chemical reaction between the amine group and a carboxylic acid halide group. Once the polymer has been produced, the aramid fibre is then created by spinning. This was developed by DuPont with their trade name Kevlar fibre and Teijin developed Twaron fibre. There are many grades available in the market with properties to suit their applications, especially in aerospace and military industries. The inherent bond strength is due to the orientation of molecules along the fibre axis. Aramid is a synthetic fibre that is produced by spinning a solid fibre from solution. The initial preparation of the polymer is generally achieved by a chemical reaction between the amine group and a carboxylic acid halide group. Once the polymer has been produced, the aramid fibre is then created by spinning.
Kevlar is manufactured from a polymer which is highly insoluble in the solution and needs to add concentrated sulfuric acid. This is necessary to keep the highly insoluble polymer in solution form during synthesis and spinning.
The manufacturing process of Kevlar is expensive and dangerous partly because it is dissolved in concentrated sulfuric acid. Unlike HDPE high molecular weight polyethylene, the kevlar® molecule is polar. This property allows other substances including water to attach themselves to the Aramid. This allows it to be more active chemically than UHMWPE (Dyneema®, Spectra®) It also means it can be bonded for example to epoxy, and it is wettable.
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DuPont™ Kevlar® is an organic fibre in the aromatic polyamide family. The unique properties and distinct chemical composition of wholly aromatic polyamides (aramids) distinguish them – and especially Kevlar® – from other commercials, man-made fibres.
Kevlar® has a unique combination of high strength, high modulus, toughness and thermal stability. It was developed for demanding industrial and advanced-technology applications. Currently, many types of Kevlar® are produced to meet a broad range of end uses.
Aramid definition—This product has been defined in different ways as per their inherent properties by different researchers.
any of a class of synthetic polyamides that are formed from aromatic monomers, and yield fibres of exceptional strength and thermal stability.
any of a class of synthetic aromatic long-chain polyamides capable of extrusion into fibres having resistance to high temperatures and great strength.
any of a group of synthetic fire-resistant and strong polyamides used to make textiles or plastics
any of a group of lightweight but very strong heat-resistant synthetic aromatic polyamide materials that are fashioned into fibres, filaments, or sheets and used especially in textiles and plastics.
any of various flame-resistant and strong synthetic fibres used in.
Keany of a class of synthetic aromatic long-chain polyamides capable of extrusion into very strong heat-resistant fibres.
English dictionary definition of aramid fibre. n. A strong, heat-resistant fibre formed of polymers with repeating aromatic groups branching from a carbon backbone, having flame retardant properties
The word aramid comes from a blend of the words “aromatic” and “polyamide” and is a general term for a manufactured fiber in which the fiber-forming substance is a long chain synthetic polyamide, in which at least 85% is of amide linkages (-CO-NH-) attached directly to two aromatic rings, (as defined by the U.S Federal)
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Advantages
Aramid main advantages are high strength and low weight. Like graphite, it has a slightly negative axial coefficient of thermal expansion, which means aramid laminates can be made thermally stable in dimensions. Unlike graphite, it is very resistant to impact and abrasion damage. It can be made waterproof when combined with other materials like epoxy. It can be used as a composite with rubber retaining its flexibility. High tensile modulus and low breakage elongation combined with very good resistance to chemicals make it the right choice for different composite structural parts in various applications.
Disadvantages
On the other side, aramid has a few disadvantages. The fibres absorb moisture, so aramid composites are more sensitive to the environment than glass or graphite composites. For this reason, it must be combined with moisture resistant materials like epoxy systems. Compressive properties are relatively poor too. Consequently, aramid is not used in bridge building or wherever this kind of resistance is needed. Also, aramid fibres are difficult to cut and to grind without special equipment (e.g. special scissors for cutting, special drill bits). Finally, they suffer some corrosion and are degraded by UV light. For this reason, they must be properly coated.
For more knitwear knowledge, please pay attention to the knitting fair.
Source: textiles school
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This article knitting fair introduces the Cardato Regenerated CO2 Neutral Brand process for creating “zero impact wool” recycled textiles. The textiles are produced in Italy’s main textile manufacturing city of Prato in Tuscany. Because during the textile production process, Cardato Regenerated CO2 Neutral Brand eliminates the carbon footprint by using regenerated raw materials, the Prato Chamber of Commerce certifies the brand as Cardato Recycled. It is an eco-friendly product that is versatile, has a limited impact on the environment, and is comfortable to wear.
Cardato Regenerated CO2 Neutral Brand
In verbal communication with Frank Monteferrante Ph.D., (retired Federal Senior Environmental Specialist), “A rise in atmospheric CO2 levels over pre-industrial levels through the burning of fossil fuels has become a major concern and is outlined in the United Nations Intergovernmental Panel on Climate Change Report (October 2018). Human CO2 generating activities through the burning of fossil fuels are estimated to have caused approximately 1.0 degree C of global warming above pre-industrial levels. This temperature increase has resulted in rising sea levels, decreases in species diversity, disruption of the marine and terrestrial ecosystem, extreme weather events, and numerous other disruptions related to a warming planet. To this end, the process instituted by Cardato recycled textiles, through a CO2 reduction process along with purchasing carbon credits, will serve to reduce CO2 output and work to address the challenges of curbing climate change.”
Prato, Italy’s main textile manufacturing city is the capital of the Province of Prato in Tuscany. It is the third largest city in central Italy after Rome and Florence. The second largest city in Tuscany, Prato is known for the introduction of regenerated textiles that dates back to the mid-nineteenth century. Prato today is touted to be the largest wool producing and recycling center in the world. In order to address the environmental issues, the needs of the fashion market, and to develop a new textile production image, the Cardato Regenerated CO2 Neutral Brand was created. Ms. Silvia Gambi, from the Chamber of Commerce in Prato, in a Wool Academy Podcast, addresses how Prato became the center of recycled wool. She explains that through diligent and constant innovation, the Prato region has developed and is recognized as a center for sustainable recycled wool fibers. Additional information about the Cardato brand can be located on the homepage (http://www.cardato.it/en/en-home/).
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The Prato Chamber of Commerce states that “eliminating the carbon print of the textile production process, while at the same time certifying the use of regenerated raw materials: this is the dual nature of the new brand, Cardato Regenerated CO2 Neutral.” It is an eco-friendly product that is versatile, has a limited impact on the environment, and is comfortable to wear. To carry the mark, “Cardato Regenerated CO2 Neutral Brand,” the textile must be produced in Prato with a minimum of sixty-five percent of recycled materials. In Prato, an estimated twenty-five thousand tons of rags annually are processed using the technique of carding, a system of processing fibers. The carded process uses short and heterogeneous pieces of yarns that are mixed together, creating diversified compositions.
The recycling process involves sorting the textile materials according to the color and the quality. Items such as linings, interlinings, and accessory parts must be removed from the used clothing, manually. Next step is carbonizing, a process that removes from the wool any vegetable impurities. Remnants are dry cleaned with hydrochloric acid and new fibers are soaked in a sulfuric acid solution. After scouring, the carbonized particles are removed by beating the treated fabrics. The final step is to render the remnants back to fibers by mechanically tearing and washing simultaneously and then drying.
Developing Zero Impact Wool
From fiber to the end product, all phases of production are done in Prato. Textile manufacturers in Prato’s ‘Green’ district are cognizant of environmental issues and concerns. In order to comply, state-of-the-art technology must be utilized, enabling the industrial district to use the Bisenzio River to recover water and also the features of the land. Using alternative energies, Prato has developed “zero impact wool” textile products. How is this accomplished? Gases that trap heat in the atmosphere are greenhouse gases (GHG) and are closely linked to energy use. Some greenhouse gases such as CO2 (carbon dioxide), occur naturally and also through human processes. In order to calculate GHG emissions in manufacturing, one must identify all stationary sources of combustion (furnaces, engines, boilers, etc.); identify all mobile sources of combustion in transportation vehicles (cars, trucks, trains, etc.); identify process emissions (physical and chemical processes used in production), and identify all fugitive emissions (intentional and unintentional releases).
Once this data is collected, calculations using generic emission factors for each fuel type consumed (carbon content of the fuel), gives the final output of greenhouse gases. With the amount of GHG emissions calculated, the company can then buy enough carbon credits from an “eco-broker” in order to offset the amount of GHG’s emitted to bring the total GHG emissions to zero, i.e., to become “carbon neutral.” The emission credits purchased from Prato’s Chamber of Commerce must correspond to production volume. One of the uses for the credits is to cover the costs of other eco-friendly programs. In this way, Cardato is achieving an eco-friendly manufacturing process by recycling wool and also reducing the carbon footprint.
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One of the first textile companies to obtain the “Cardato Recycled Brand,” is Intespra Industria Tessuti Pratesi (Textile Industry Pratesi), a successful leading textile house in Prato since 1983. Using the minimum required sixty-five percent of pure virgin or reused wool fiber and Cardato certified the company creates “classic fabrics with a modern look, in different weights suitable for jackets and coats.” The company produces a wide range of yarn-dyed patterns and piece dyed fabrics with a broad breadth of colors. State-of-the-art technology allows the fabrics to be textured (printed, laminated bonded, flocked, coated, etc.) and infused with performance properties such as washable, water and wind resistant, antistatic and anti-pilling. According to an article published in the October 2017 issue of the Wearme Fashion Magazine written by Ms. Sara Volpi, “Intespra’s final products are sustainable and respect both the environment and animals while still guaranteeing high-quality standards despite being crafted with recycled wool.”
For more knitwear knowledge, please pay attention to the knitting fair.
Source: textiles school
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Linen fabric is made from the cellulose fibers that grow inside of the stalks of the flax plant, or Linum usitatissimum, one of the oldest cultivated plants in human history. This article Knitting fair introduces to you.
Textiles in a Linen weave texture, even when made of cotton, hemp, and other non-flax fibers, are also loosely referred to as “linen”. Such fabrics generally also have their own specific names, for example, fine cotton yarn in a linen-style weave is called Madapolam.
Flax/Linen Clothing
Linen fabric has many attractive properties and all of them are most easily appreciated when wearing linen clothing. Over the past 30 years, the end use of linen has changed dramatically. Approximately 70% of linen production in the 1990s was for apparel textiles, whereas in the 1970s only about 5% was used for fashion fabrics.
The main benefit of wearing linen clothes in hot weather is the coolness they provide. Thanks to the weave and linen fiber specifics linen fabric allow more airflow and its structure means it stays away from your skin allowing better airflow over your body. Linen is a “stiff” fabric and is less likely to cling to the skin; when it billows away, it quickly dries out and becomes cool again. Summer clothes made of linen possess high air permeability, which allows air to flow through the fabric easily and allows the body to breathe.
Linen is a “stiff” fabric and is less likely to cling to the skin; when it billows away, it quickly dries out and becomes cool again. Summer clothes made of linen possess high air permeability, which allows air to flow through the fabric easily and allows the body to breathe.
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Next, to coolness and high absorbency, linen has one more very favorable property – good heat conductivity characteristics. Heat conductivity refers to the extent to which heat can be conveyed through the fabric. As linen quickly allows the heat to escape, it further improves cooling. It is claimed, that heat conductivity of linen is five times higher than wool and eighteen times higher than silk. One more thing – linen weave reflects heat better, too. This means linen blouse, linen dress or shirt has good “shading” properties as well and again – the wearer of linen clothing feels cooler.
The legacy of Flax/Linen
In the past, linen was also used for books (the only surviving example of which is the Liber Linteus). Due to its strength, in the Middle Ages linen was used for shields, gambesons, and bowstrings; in classical antiquity, it was used to make a type of body armor, referred to as a linothorax.
Flax/Linen Applications
Linen uses range across bed and bath fabrics (tablecloths, bath towels, dish towels, bed sheets); home and commercial furnishing items (wallpaper/wall coverings, upholstery, window treatments); apparel items (suits, dresses, skirts, shirts); and industrial products (luggage, canvases, sewing thread). It was once the preferred yarn for hand sewing the uppers of moccasin-style shoes (loafers) but has been replaced by synthetics.
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Flax/Linen Source
Linen is bast fiber. Linen is a textile made from hairs of the flax plant. Linen fabric is made from the cellulose fibers that grow inside of the stalks of the flax plant, or Linum usitatissimum, one of the oldest cultivated plants in human history. Flax is an annual plant, which means it only lives for one growing season. It is thicker than cotton and linen fiber has variable lengths, most of which are very long. This contributes to strength, which contributes to longevity. Linen fabric lasts a very long time.
Linen is laborious to manufacture, but the fiber is very absorbent and garments made of linen are valued for their exceptional coolness and freshness in hot weather. Linen/Flax fibers vary in length from about 25 to 150 mm (1 to 6 inches) and average 12–16 micrometers in diameter. There are two varieties: shorter tow fibers used for coarser fabrics and longer line fibers used for finer fabrics. Flax fibers can usually be identified by their “nodes” which add to the flexibility and texture of the fabric. The cross-section of the linen fiber is made up of irregular polygonal shapes which contribute to the coarse texture of the fabric.
For more knitwear knowledge, please pay attention to the knitting fair.
Source: textiles school
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