Which is better Kevlar or PE fiber in the material?
First, give the subject a brief introduction to aramid and PE.
1. Aramid fiber equipment Aramid fiber, also known as aramid fiber (chemical name is phthalamide), was born in the late 1960s. It is a new type of high-tech synthetic fiber with the characteristics of high temperature resistance, acid and alkali resistance. , light weight, high strength, has been widely used in bulletproof protective equipment, construction and electronic equipment and other fields.
But aramid also has two fatal disadvantages:
1) It will degrade when exposed to 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 body armor should not be used for a long time 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.
Premium quality aramid is also more expensive than PE, perhaps 30% to 50% more. At present, bulletproof products using aramid fiber are gradually decreasing and are beginning to be replaced by PE bulletproof products. Unless it is in a special environment or has special requirements, such as the high temperature in the Middle East, it is recommended to use PE bulletproof equipment.
The PE in the above PE fiber equipment actually refers to UHMW-PE, that is, ultra-high molecular weight polyethylene. It is a high-performance organic fiber developed in the early 1980s, and is known as carbon fiber and aramid fiber in today's world. Three high-tech fibers. The plastic bags we use in our daily life are actually polyethylene products, which have ultra-high stability and are extremely difficult to degrade, causing serious environmental pollution. But it is precisely because of this characteristic that it becomes an ideal material for body armor. In addition, it also has the characteristics of low temperature resistance, UV resistance and waterproof.
In terms of defense against low-speed bullets, the bulletproof performance of UHMW-PE fiber is about 30% higher than that of aramid fiber;
In terms of defense against high-speed bullets, the bulletproof ability of UHMW-PE fiber is 1.5~2 times that of aramid fiber, so PE is currently recognized as the best bulletproof material.
However, UHMW-PE also has some disadvantages: its high temperature resistance is far less than that of aramid fiber. The use temperature of UHMWPE bulletproof products needs to be controlled within 80°C (to 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 it will melt when the temperature reaches 150°C or higher. Aramid bulletproof products can still maintain structural stability and good protective performance at a high temperature of 200 °C. Therefore, PE bulletproof products are not suitable for use in high temperature environments.
In addition, PE is not as creep resistant as aramid, and devices using PE will slowly deform under constant pressure. Therefore, equipment with complex shapes such as helmets that need to withstand pressure for a long time cannot be made of PE.
In addition to these characteristics, the price of PE is also much lower than that of the aforementioned aramid.
Generally speaking, PE and aramid have their own advantages and disadvantages. However, PE is now more widely used as a bulletproof layer. Or choose the bulletproof equipment that suits you according to your actual situation.
