Aramid facts for kids
Aramid fibers are super strong, heat-resistant materials. Think of them as a special type of synthetic fiber – that means they're made by people, not found in nature.
These fibers are used in many cool ways! You can find them in things like body armor to protect soldiers and police, in parts of aerospace vehicles, and even in ropes for boats. They're also used as a safe replacement for asbestos (an old material that was dangerous). Plus, they show up in everyday items like phone cases and tennis rackets because they're so light and tough.
What makes them so strong? Their tiny molecules are lined up perfectly, making the fibers incredibly hard to break. They also have a very high melting point, over 500 degrees Celsius (that's super hot!).
Some well-known brand names for aramid fibers include Kevlar, Nomex, and Twaron.
Contents
What are Aramid Fibers?
The word aramid is a shorter way to say "aromatic polyamide." It's a special term created in the 1970s to describe this unique group of fibers.
The "aromatic" part means these fibers contain special ring-shaped groups of carbon atoms. The "polyamide" part means these rings are linked together by "amide" connections. For a fiber to be called an aramid, most of these connections must be between two of these aromatic rings.
Para-aramids and Meta-aramids
Aramids come in two main types, depending on how their parts connect. Imagine the carbon atoms in a ring are numbered.
- Para-aramids have their connections at positions 1 and 4. This means the connection points are directly opposite each other on the ring. The picture shows a para-aramid.
- Meta-aramids have their connections at positions 1 and 3. Here, the connection points are two atoms apart on the ring.
Aramid History
Aramid fibers first appeared in the early 1960s. One of the first was a meta-aramid fiber called HT-1, later known as Nomex, made by a company called DuPont. This fiber was special because it could handle extreme heat without melting or catching fire easily.
Nomex became very popular for making protective clothing, like firefighter suits. It was also used for air filters and electrical insulation. Other companies like Teijin Aramid and Toray also started making meta-aramids.
Later, in the 1960s and 1970s, a super-strong type of aramid called a para-aramid was developed. DuPont was the first to introduce this in 1973, calling it Kevlar. Kevlar is still one of the most famous aramid fibers today.
Another company, Akzo, introduced a similar fiber called Twaron in 1978. These para-aramids are used in high-tech areas like aerospace and for "bullet-proof" body armor.
Both meta-aramid and para-aramid fibers can also be made into a special kind of paper. This aramid paper is used for electrical insulation and in building materials. DuPont made Nomex paper in the 1960s, and other companies now make similar aramid papers.
Is Aramid Safe?
In the 1990s, some early studies looked at how aramid fibers might affect cells. There was some concern that they could act like asbestos, which is known to be harmful.
However, more recent research in 2009 showed good news. Studies found that when tiny aramid fibers are breathed in, they are quickly broken down and removed from the body. This means they are likely to pose very little risk to health.
How Aramids are Made
Making aramid fibers is a complex process.
Making the Polymer
Aramids are generally made by mixing two types of chemicals: an "amine" group and a "carboxylic acid halide" group. Famous aramid polymers like Kevlar, Twaron, and Nomex are made from specific "diamine" and "diacid" chemicals.
- Nomex and similar fibers are mostly "meta-linked."
- Kevlar and Twaron are "para-linked."
To make para-aramids like Kevlar, the chemicals are mixed in a special liquid. This liquid helps the polymer dissolve and form correctly.
Spinning the Fiber
Once the polymer is made, it's turned into a solid fiber. This happens by pushing the dissolved polymer through tiny holes, like squeezing toothpaste from a tube. For para-aramids, a very strong acid called sulfuric acid is often used to dissolve the polymer before spinning.
What Aramids Look Like
Aramid fibers can come in different forms:
Other Types of Aramids
Besides meta-aramids like Nomex, there are other types called "copolyamides." One well-known example is Technora, developed by Teijin. The way Technora is made is a bit simpler, using fewer chemicals.
Aramid Fiber Features
Aramid fibers have many special qualities that make them useful.
General Features
- They are very good at resisting wear and tear (abrasion).
- They don't react much with many common chemicals.
- They don't conduct electricity.
- They have a very high melting point (over 500°C).
- They don't catch fire easily.
- They stay strong even at high temperatures.
- They can be sensitive to strong acids and salts.
- They can be damaged by ultraviolet light (like from the sun).
- They can build up static electricity.
Para-aramid Features
- Para-aramid fibers, like Kevlar and Twaron, are incredibly strong for their weight.
- They are very stiff and hard to stretch.
- They don't stretch much before breaking (only about 3.5%).
- They are hard to dye, so they are usually colored during their production.
What Aramids are Used For
Aramid fibers are used in a huge variety of products:
- Clothing that resists flames
- Clothing and helmets that protect from heat
- Body armor
- composite materials (materials made from two or more different materials)
- Replacing asbestos in things like brake linings
- Fabrics for filtering hot air
- tires
- Reinforcing rubber products
- Strong ropes and cables
- V-belts for cars and machines
- Wicks for fire dancing
- Protecting optical fiber cables
- Sail cloth for boats
- sporting goods like tennis rackets and hockey sticks
- drumheads
- loudspeaker parts
- Boat hulls
- Reinforcing concrete
- Tennis strings
- Snowboards
- Parts of jet engines
- Reinforcing asphalt for roads
- Special ropes for rock climbers (called Prusiks)
See also
In Spanish: Aramida para niños Para-aramid
- Kevlar
- Technora
- Twaron
- Heracron
Meta-aramid
- Nomex
- Teijinconex
Others
