First, give the subject a brief introduction to aramid and PE.
Aramid fiber equipment Aramid, also known as Kevlar (the chemical name is phthalamide) was born in the late 1960s. It is a new type of high-tech synthetic fiber, which has high temperature resistance, acid and alkali resistance., Light weight, high strength and other advantages, has been widely used in bullet-proof protective equipment, construction and electronic equipment and other fields.
But aramid also has two fatal shortcomings:
1) It will degrade when encountering ultraviolet rays; it is easy to hydrolyze, even if it is stored in a dry environment, it will absorb moisture in the air and gradually hydrolyze.
Therefore, aramid bulletproof inserts and bulletproof vests are not suitable for long-term use in strong ultraviolet and humid environments, which will greatly reduce their protective performance and service life. In addition, the poor stability and short life of aramid also limit the further application of aramid in the field of bulletproof.
The price of high-quality aramid is also higher than that of PE, which may be 30% to 50% more. At present, bulletproof products using aramid have gradually decreased and begun to be replaced by PE bulletproof products. Unless it is in a special environment or has special requirements, such as the high temperature of the Middle East, it is recommended to use PE material bulletproof equipment.
1. PE mentioned before in PE fiber equipment actually refers to UHMW-PE, which is ultra-high molecular weight polyethylene. It is a high-performance organic fiber developed in the early 1980s, and is called the world today together with carbon fiber and aramid. Three high-tech fibers. The plastic bags used in our daily life are actually polyethylene products, which have super high stability and are extremely difficult to degrade, which causes serious environmental pollution. But it is precisely because of this characteristic that it has become an ideal material for making body armor. In addition, it has the characteristics of low temperature resistance, UV resistance, and water resistance.
In terms of defense against low-speed bullets, UHMW-PE fiber’s ballistic resistance is about 30% higher than that of aramid fiber;
In terms of defense against high-speed bullets, the bulletproof capability of UHMW-PE fiber is 1.5 to 2 times that of aramid fiber, so PE is currently recognized as the highest quality bulletproof material.
However, UHMW-PE also has some shortcomings: its high temperature resistance is far less than that of aramid. The use temperature of UHMWPE bulletproof products needs to be controlled within 80°C (which can meet the temperature requirements of the human body and equipment -temperature resistance 55°C). Once this temperature is exceeded, its performance will drop rapidly, and when the temperature reaches 150°C or higher, it will melt. The aramid bulletproof products can still maintain a stable structure and good protection performance in a high temperature environment of 200 ℃. Therefore, PE bulletproof products are not suitable for use in high temperature environments.
In addition, the creep resistance of PE is not as good as that of aramid, and equipment using PE will deform slowly when subjected to continuous pressure. Therefore, equipment such as helmets that have complex shapes and need to withstand pressure for a long time cannot be made of PE.
In addition to these characteristics, the price of PE is much lower than that of aramid as mentioned earlier.
In general, PE and aramid have their own advantages and disadvantages. However, it is more widely used nowadays to use PE as a bulletproof layer. It is still necessary to choose the bulletproof equipment that suits you according to your actual situation.
Post time: Aug-20-2021
