As a polymer, Kevlar consists of smaller molecules linked together to form a larger one. Kevlar’s resilient fabric has chains of repeating units. The chains exhibit nematic activity by spontaneously aligning parallel to one another, much like liquid crystals (used to make LCD televisions). This material’s incredible tensile strength is due to the chains’ hydrogen bonds. Forging the polymer through a sieve when it is incredibly concentrated creates the long, thick fibers used to make the highly rigid mats and sheets. 

A material’s tensile strength is the amount of resistance it provides to a force to keep it from lengthening. When compared to the tensile strength of steel wire, Kevlar is approximately eight times stronger. Furthermore, despite its durability, the material is not too heavy, which explains why Kevlar vests exist. It has a high melting point (it only decomposes at about 450 °C) and a low expansion temperature (it barely changes size when heated), making it a superior material for high temperatures. In addition, it can withstand shallow temperatures without breaking down into a brittle state. It can withstand a lot of abuse without showing signs of wear. There is a wide variety of Kevlar available, with the fundamental distinction being between high- and low-quality grades. Kevlar K29 and K49 are the most popular versions. Kevlar is a crucial material with potentially game-changing applications, so researchers and inventors keep chipping away at it, especially with the invention of Kevlar vests.

Despite its apparent greatness, Kevlar is not without its drawbacks. It has to be mass-produced at a lower price through innovative production methods to increase its widespread and intensive use. Since it is so difficult to produce, it is, unsurprisingly, highly costly. The high cost of production makes Kevlar vests expensive and not very accessible to users of bulletproof vests. Also, Kevlar has a low compressive property, so new developments are needed to improve this aspect of the material. While its incredible tensile strength is undoubtedly a benefit, the material’s inflexibility poses a significant drawback for usage in products like Kevlar vests and body suits, where mobility is of the utmost importance. 

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