Do you know the difference between ARAMID and UHMW-PE materials for bulletproof helmets?
DATE: Oct 22nd, 2023
ARAMID and UHMW-PE are two common materials for ballistic helmets. They have some significant differences in performance and characteristics. Here's how they compare:
ARAMID: ARAMID is a synthetic fiber, such as Kevlar, which is composed of aromatic polyamide and has extremely high strength and stiffness. It is a type of organic fiber.
UHMW-PE: UHMW-PE stands for ultra-high molecular weight polyethylene, which is a high-performance polymer with an extremely high molecular mass. It is a plastic-based material.
Strength and stiffness:
ARAMID: ARAMID material has high shear strength and puncture resistance, making it excellent in ballistic applications.
UHMW-PE: UHMW-PE material has excellent impact absorption capabilities and can effectively absorb and disperse impact, but it is relatively fragile.
ARAMID: ARAMID material is relatively heavy because it is made of fiber.
UHMW-PE: UHMW-PE is lightweight and relatively lightweight, making the helmet more comfortable and reducing the burden on the user.
ARAMID: ARAMID material is not corrosion-resistant and is easily affected by humidity and chemicals.
UHMW-PE: UHMW-PE has better resistance to corrosion from water and chemicals.
ARAMID: ARAMID materials may decompose at high temperatures, reducing their performance.
UHMW-PE: UHMW-PE is able to maintain performance at a certain level of high temperature, but it also has temperature limitations.
The degree of depression caused by bullet impact: (shown by the test results of many JINTENG customers)
ARAMID (such as Kevlar):
ARAMID materials usually show good anti-dent performance when bullets impact, and are not prone to obvious dents. This is because ARAMID fiber has high strength and stiffness, which can effectively disperse impact forces, thereby reducing the occurrence of dents and preventing the wearer's body from being harmed by product deformation.
ARAMID generally maintains good shape integrity, especially in the face of bullet impact.
UHMW-PE materials usually show larger dents when bullets impact because it is a softer material. UHMW-PE has excellent impact absorption capabilities, but this can result in a noticeable dent at the point of impact.
Although UHMW-PE can effectively absorb impact, it may not be as good as ARAMID in maintaining material integrity.
ARAMID: ARAMID is generally more expensive than UHMW-PE because its manufacturing process is more complex.
UHMW-PE: UHMW-PE is relatively cheaper because it is a plastic-based material.
Additionally, helmets were traditionally required to be able to protect against only flying rocks and metal fragments on the battlefield. The V50 value is usually used to measure the protective capabilities of a helmet. (The helmet is shot with an inclined cylindrical projectile with a mass of 1.1 grams at different speeds at a specified distance. When the probability of penetration reaches 50%, the average speed of the projectile is called the V50 value of the helmet.) Of course, the higher the V50 value, The better the helmet performs
PE here refers to ultra-high molecular weight polyethylene, the abbreviation of ultra-high molecular weight polyethylene. It is a high-performance organic fiber developed in the early 1980s. It has extremely high ultra-high stability, low temperature resistance, UV resistance and water resistance, making the maintenance of PE bulletproof products more convenient; but it also has some disadvantages. For example, it is susceptible to high temperatures and is not as resistant to creep as aramid. Therefore, PE bulletproof products are not recommended for use in high-temperature environments, such as the Middle East and tropical Africa, where temperatures can often reach 50~60°C. In addition, due to its poor creep resistance, it cannot be used under high pressure for a long time. But compared to Kevlar helmets, it is lighter and cheaper.
Aramid, also known as Kevlar, was born in the late 1960s. It is a new type of high-tech synthetic fiber with strong high temperature resistance, good anti-corrosion performance, light weight and high strength. However, aramid has two fatal disadvantages:
Vulnerable to UV rays. It always degrades when exposed to UV rays.
Easy to hydrolyze, even in a dry environment, it will still absorb moisture in the air and gradually hydrolyze. Therefore, aramid equipment should not be used or stored in environments with strong UV rays and high humidity for a long time, otherwise its protective performance and service life will be greatly reduced. But even so, Kevlar helmets are still the mainstream equipment of the U.S. Army and European armies. In addition, the helmet is coated with paint and polyurethane coating to reduce damage caused by moisture and UV radiation. If the coating on your helmet is damaged, you'd better paint it or replace it with a new one as soon as possible. The increased use of Kevlar has pushed up the price of Kevlar raw materials
To sum up, ARAMID materials usually have better puncture resistance, while UHMW-PE has certain advantages in lightweight, corrosion resistance and impact absorption properties. Material selection depends on specific application needs and budgetary considerations.