Steel and ceramic body armor plates have a fairly long history relative to modern ballistic armor. However newer technology and materials like polyethylene, specifically UHMWPE, ultra high molecular weight polyethylene have presented interesting opportunities for manufacturing armor. Polyethylene has several advantages over more traditional materials in terms of weight and comfort. We are going to go through a timeline of polyethylene itself, including it’s adaption to use for body armor, as well as the benefits and limitations for its use.
Discovery and Early Development
Polyethylene is one of the most widely used plastics today, and has a fascinating history.
The discovery of polyethylene, like most great things came as an accident. It was first created by the German chemist Hans von Pechmann who produced it accidentally in 1898 while heating diazomethane, a highly reactive compound. However he did not continue much further work with his creation.
About 40 years later two scientists in England unintentionally produced polyethylene in an attempt to produce a gasoline additive. Instead they ended up with a white, waxy substance that was resistant to heat and chemicals and had excellent insulating properties. It was a form of polyethylene they named “polythene.”
World War II and Mass Production
The mass production of polyethylene started during World War II when its potential as an insulator for radar cables was discovered. It replaced a naturally occurring form of latex that was previously used as an insulator, but was in short supply due to the war. Due to its value and scarcity it was kept closely guarded.
Post-war several companies began to produce polyethylene, and the plastic quickly found a wide range of uses due to its versatility.
Development of High-Density Polyethylene (HDPE)
In the early 1950s two researchers named Paul Hogan and Robert Banks working at Phillips Petroleum developed a new type of polyethylene, known as high-density polyethylene (HDPE). HDPE was more rigid and had a higher melting point than the previously produced low-density polyethylene. This development opened even more applications for polyethylene, including milk jugs, laundry detergent containers, and garbage bins.
Ultra High Molecular Weight Polyethylene (UHMWPE)
In the 1950s and 1960s Dutch and German researchers developed a process to create ultra-high-molecular-weight polyethylene (UHMWPE). This variant had even higher strength and resistance properties. It was first used in artificial hip joints in the 1960s, and by the late 1970s it was used in making bulletproof vests and helmets.
Today, polyethylene is used in an extensive range of products from food packaging to water pipes, and from medical devices to body armor. Its diverse properties, strength, durability, flexibility, and resistance to chemicals and moisture, continue to make it a valuable material across many industries. The future of polyethylene will likely see continued innovation and the development of new variants to suit an ever-widening range of applications.
What Is Polyethylene?
Polyethylene is a type of plastic widely used in various products due to its many beneficial properties mentioned above. In the context of body armor, polyethylene plates have gained recognition for their capacity to withstand both rifle and pistol rounds- depending on the manufacturing process used to form the armor.
What Is Polyethylene Body Armor Made Of?
Polyethylene body armor plates are manufactured by bonding Ultra High Molecular Weight Polyethylene Fibers onto a High Density Polyethylene sheet. The process results in a material that’s not only tough and flexible.
The sheets are then layered together and bonded before being sealed into a protective outer layer. In making soft body armor the process more or less ends here. If the plate is being made into a hard armor panel the process continues to make the plate very ridged. If the plate is to become a rifle plate then many more layers are added to create a thick, light, and incredibly hard armor plate capable of achieving NIJ level 3 certification, a perfect addition to any body armor vest.
What Is The Weight of Polyethylene Plates?
Alright to expand on that answer it depends on the purpose of the plate. If the plate is designed as handgun armor, like the NIJ level IIIA from Tacticon, the plate is right about one (1) pound.
If the plate will be made into an SRT plate, designed to stop intermediate cartridges like 5.56 and 7.62×39, then expect around 2.5 pounds, and incredibly lightweight body armor plate. If the plate is to achieve NIJ level III body armor rating capable of stopping 6 rounds of 7.62×51 then the plate will be about three (3) pounds. In any configuration, these plates will weigh less than their steel or ceramic counterparts of the same threat level.
Polyethylene Body Armor Plates Heat Resistance
UHMWPE body armor plates are moderately resistant to temperature extremes. However, prolonged exposure to temperatures below -15F or above 150F can degrade the material’s protective properties. Melting from extreme heat can cause the plates to fail.
Ceramic Vs Polyethylene Plates
Polyethylene plates are lighter than ceramic plates, making them more comfortable to wear over long periods. Both types provide excellent protection, but polyethylene plates are generally more resistant to multiple hits. This is in large part due to the ceramic strike face of ceramic plates breaking apart due to a bullet strike. Similarly, ceramic plates have a greater danger of cracking if dropped. Polyethylene plates are often vulnerable to rounds that incorporate a steel penetrating tip such as M855 or 7.62×39 MSC. Ceramic can also be found in multi curve plate designs, curved armor plates are generally regarded as more comfortable.
Kevlar Vs Polyethylene
While both Kevlar and UHMWPE are in the same material group as they’re both woven, there are differences. Kevlar is what is called an aramid fiber, whereas polyethylene is synthetic which makes it lighter. Both can achieve the same NIJ ratings for soft pistol armor, however PE has the ability to be made thinner to achieve the same level of protection.
What Does UHMWPE Stand For?
UHMWPE stands for Ultra High Molecular Weight Polyethylene. The term refers to the extremely long chains of polyethylene that make up the material. These long chains create a strong bond resulting in a highly durable and impact resistant material, ideal for use in body armor.
UHMWPE Body Armor Plates Material
UHMWPE body armor is a two-phase composite of crystalline and amorphous phases. This unique composition contributes to the material’s strength and toughness, making it an excellent choice for body armor.
UHMWPE Body Armor Weight
UHMWPE body armor is among the lightest options available. As we discussed the hard armor plates earlier this section pertains to soft armor. UHMWPE is one of the lightest forms of PE due to its long chains forming many bonds, and as such uses less material. The end result of this is a panel of soft armor that is very thin, very light, yet very capable of stopping handgun threats. You can expect a single panel to weight between 1-3 pounds depending on the size and amount of coverage it is made to give. It is often directly compared to Kevlar, but weighs about ½ for the same configuration at the same threat level.
What Is The UHMWPE Melting Point
UHMWPE can withstand temperatures up to around 150F. In practical terms, this means you should avoid putting it in the dryer or leaving it in the hot sun or a warm car for extended periods. Seriously, please don’t wash body armor in the dryer, I have actually heard stories.
UHMWPE Armor Vs Ceramic
UHMWPE and ceramic armor offer similar protection levels. However, UHMWPE is generally lighter, making it more comfortable for long-term use. While ceramic plates can crack from heavy impacts, UHMWPE plates are more durable, though they are less resistant to high temperatures. Remember, ceramic is resistant to steel tipped ammo, UHMWPE is not.
UHMWPE Vs Kevlar
While UHMWPE and Kevlar both offer high levels of protection, UHMWPE is generally lighter. On the other hand, Kevlar has a higher heat resistance. Both materials are durable, but the lifespan can be affected by factors such as exposure to sunlight, moisture, and rough handling.
Polyethylene/UHMWPE Body Armor Plates FAQ
What is polyethylene body armor made of? Polyethylene body armor is made from Ultra High Molecular Weight Polyethylene (UHMWPE), a type of polyethylene compound with extremely long chains that give it a high degree of strength and durability.
Why is polyethylene used for body armor? Polyethylene is used for body armor due to its strong, lightweight properties. It is incredibly tough, offering high resistance to impacts, yet it is significantly lighter than traditional materials like steel or ceramic making it more comfortable to wear.
Is polyethylene fabric bulletproof? The fabric is not inherently bulletproof, polyethylene fabric can be processed in a way (through layering and pressurization) to create a material that can stop bullets.
Is UHMWPE better than Kevlar?
No? Yes? It is hard to give a definite answer concerning soft armor. UHMWPE is lighter, can be thinner, and more flexible. Consider that Kevlar came first and really paved the way for modern UHMWPE armor, so it would be better considered a predecessor.
Is polyethylene better than Kevlar? Like the comparison with UHMWPE, whether polyethylene is “better” than Kevlar largely depends on the application. Polyethylene has a higher tensile strength and is lighter, but Kevlar offers better heat resistance.
Does polyethylene armor expire? Polyethylene armor does have a shelf life typically around 5-7 years. However, this can vary depending on factors such as exposure to UV light and harsh weather conditions which can degrade the material faster. Always check with the manufacturer for specific guidance.
Is polyethylene safe for skin? Yes, polyethylene is safe for skin contact. It is a widely used material in a variety of consumer products including many that encounter skin.
What is the shelf life of UHMWPE? The shelf life of UHMWPE products, like body armor plates can vary based on many factors including storage conditions and usage, but typically ranges from 5 to 7 years. Always refer to manufacturer’s guidelines for specific products.
Is Kevlar made of polyethylene? No, Kevlar is not made of polyethylene. Kevlar is an aramid, a type of synthetic fiber made by a completely different process. Both Kevlar and polyethylene have high strength-to-weight ratios and are used in body armor, but they are different materials.
Does polyethylene break easily? No, polyethylene does not break easily. In fact, it is known for its exceptional durability and resistance to impact, which is why it’s used in applications such as body armor.
How much do polyethylene plates weigh? The weight of polyethylene plates can vary based on their size and design, but they are generally lighter than comparable steel or ceramic plates. For example, a level III 10″x12″ polyethylene plate might weigh around 2-4 pounds, where a steel plate weights 7-10 pounds, and a ceramic may weight 4-7 pounds.
Polyethylene and UHMWPE body armor plates present a compelling option for those seeking lightweight body armor. However, it’s important to assess your personal needs, understand the specific advantages and limitations of these materials, and make informed decisions when it comes to personal safety. Remember that the choice of body armor should balance protection, comfort, and mobility based on your specific situation.
Whether you opt for polyethylene/UHMWPE or another material like ceramic or steel keep in mind that the most important thing is that your body armor fits your needs and offers the level of protection necessary for your specific use case.
The opinions expressed in this post are those of the author and do not necessarily reflect the views and opinions of Tacticon Armament.