Economic Impact. The production of fibers like Kevlar is really an oligopoly. Du Pont, being the producer of Kevlar is the largest producer para-aramids in the world. These three sites have a production capacity of Russia also produces a very low percentage of para-aramids called Fenylene. Below is a production table for all para fibers in the last two decades. Production in Western Europe and Japan has jumped up greatly in the last ten years.
Also Du Pont accounts for about one-third of the total production in Europe and about one-half of the production in Japan. World Production of Para Fibers millions of pounds. United States. Western Europe. Consumption of para-aramids in the three major regions: United States, Western Europe, and Japan hit 39 million pounds in and increased to 47 million pounds in Dunlop Tire Corp.
Outside of the U. Even with the expanding market as it currently is, widespread growth will not be realized until the costs of production falls. The properties of Nomex include great electrical insulation properties at high temperatures.
The Kevlar adds stability and tear resistance to the material. The general properties of Nomex are listed below. This properties cause paper made by Nomex to be stronger and tougher than regular cellulosic papers.
The difference between Kevlar and Nomex is the location of the amide linkages on the aromatic ring. Those differences cause Nomex to a lower modulus and tensile strength and a higher elongation and solubility in organic solvents. The chemical name of Nomex is poly m-phenylene isophthalamide , which is produced from the reaction of m-phenylenediamine and isophthaloyl chloride whose structures are shown below.
The solution is dry spun through spinnerets. Nomex can be produced as a continuous filament yarn, staple, spun yarn, floc, pressboard, paper, needle felt, or as a fabric.
Next we will take a look at the economics of producing Nomex. The growth of meta-aramid fibers has grown steadily over the last 10 years. At the same time the U. The table below shows production patterns of meta-aramids since World production of Meta- Aramid fibers millions of pounds. In fact, Kevlar is actually a brand, and its name has been trademarked by the company that initially produced them. There are several subtle differences that we can continue to discuss, but in terms of their use in body armor, these two materials are essentially the same.
In fact, most manufacturers and producers classify Kevlar and Aramid as the same thing, and they usually refer to it as Kevlar. In general, Kevlar and Aramid are mainly used for various commercial applications, but one of its applications that needs to be taken seriously is its use in body armor. That being said, it makes sense why people trust Kevlar for the use of body armor.
As explained earlier, Kevlar inherits many of the same benefits that general Aramids do, but it becomes more rigid and durable in general due to its increased bond strength. Some of the biggest advantages for using Kevlar in body armor include:. One common theme that you may have noticed in the list of advantages is the fact that Kevlar is resistant to the environment in general. Essentially, Kevlar holds its shape and form no matter what kind of environment or condition you put it in.
Even when placed in hot water, Kevlar armor is known to be resistant to moisture as well. This is very important because Kevlar armor is used in many different types of situations.
Many people think that only the army or military uses high-grade Kevlar armor, but local law enforcement and even firefighters are known to use Kevlar armor on certain occasions. Another key benefit that comes as a surprise to most people is the fact that Kevlar is also resistant to chemical attacks. This kind of protection is much more valuable to the military rather than those working in local law enforcement or protection.
At the military level, soldiers may experience attacks outside of guns and bullets, so the fact that Kevlar can help protect against chemical warfare is crucial. This is what makes Kevlar very good under impact force, which is very applicable for preventing bullets. However, when you start to stretch and pull Kevlar, it becomes more of an issue, and that will be discussed later on in the article.
You can now see why Kevlar is so strong, but how does that directly translate to preventing bullets from getting through it?
The biggest protection Kevlar armor provides is that it reduces the force of impact, and this especially applies to high-speed bullets. Up until this point, it may seem as though Kevlar has no significant drawbacks, and depending on its application, that might be right. However, nothing exists without some sort of downside, and that even applies to something as strong as Kevlar.
When under the following conditions, the effectiveness of Kevlar armor can start to drop dramatically:. That is still true for the most part, but it does have one glaring exception: the sun. When exposed to ultraviolet light for long periods, the Kevlar armor can start to degrade.
Depending on the time of exposure and intensity, it can have various effects. In the best-case scenario, all that could happen is that your Kevlar armor could start to discolor. During production of Aramid composites, as early as at design phase, some changes and modifications are made to adapt molds appropriately and reduce the amount of cutting required after demolding.
Aramid fibers have modest bonding comparing to glass fibers or carbon fibers and modest resin penetration. Therefore for production of aramid composites it is recommended to use epoxy resins that offer better performance for bonding of aramid fabric layers.
Aramid fibers have poor resistance to UV. UV radiation sunlight causes degradation of aramid fibers. Therefore protection is required which can be a top coat or material layer e. Aramid is a costly material with a price similar to carbon fiber. Aramid fibers offer compression strength lower than glass fibers or carbon fibers , therefore hybrid fabrics are widely used in components exposed to high compression, such as a structure including a combination of aramid and carbon fiber.
Kevlar strengthening of timing belts increases their durability and reduces the risk of breakage. Cut resistant safety gloves. Rubberized components reinforcement e. Tire reinforcement. Optical cables provided with aramid fiber lining that prevents cracking and protects against momentary contact with fire.
Sail cloth. Aramid paper used in honeycomb. At the same time this material exhibits some disadvantages such as difficult treatment and processing or moisture absorption. We hope that reading this paper will allow everybody to learn more about the advantages and disadvantages, as well as contribute to its optimal use by engineers and designers.
Dexcraft supplies aramid composite products such as bulletproof vests , racing car body components, aramid sheets and other composites.
It is generally used where the power transmission requirements are very critical, apart from space restrictions on the permissible installation and take up allowances. History Aramid refers to specific materials that are available under different commercial names. Nowadays Kevlar is the best known of all Aramid composites. Aramid is a material with extremely high cut resistance, often used in the production of protective clothing. Advantages of Aramid composites High resistance to impact and cracking Aramid features extraordinary resistance to impact and it does not crack under pressure as it is tough and allows significant energy absorption.
Kevlar protects kayak hulls from stones and roots. Moderate stiffness — fill the gap between glass fiber and carbon fiber Aramid composites have higher stiffness higher than glass fiber composites and significantly lower than carbon fiber composites. Low thermal expansion Aramid is very stable when exposed to high temperatures with almost zero and slightly negative thermal expansion coefficient that is equivalent to Non-conductive Aramid is a good insulator and does not conduct electricity.
Resistance to abrasion Aramid composites are widely used for parts and components exposed to abrasion e. Vibration absorption One specific property of Aramid composites relates to vibration absorption and consequently Aramid is used for the manufacture of components exposed to vibration e.
Aramid helicopter rotors reduce vibration and provide ballistic protection from missiles up to 23 mm. Aramid is used for the production of military radomes providing ballistic protection. Use with other fabrics and creation of hybrid composites Aramid fabrics may be used in carbon fiber composites and glass ones by modifying parameters according to requirements, which provides many possibilities for suppliers of composite products. Hybrid fabrics — i.
Kevlar-carbon fabrics — combine the best characteristics of both materials. Difficult treatment and processing Aramid fibers are difficult to cut. Cutting aramid fabrics is a difficult task — either special scissors or laser cutting are used. UV related degradation Aramid fibers have poor resistance to UV. High costs Aramid is a costly material with a price similar to carbon fiber. Low compression strength Aramid fibers offer compression strength lower than glass fibers or carbon fibers , therefore hybrid fabrics are widely used in components exposed to high compression, such as a structure including a combination of aramid and carbon fiber.
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