"Polyparaphenylene terephthalamide" is the chemical name for Kevlar, an aromatic polyamide synthetic fiber. It has exceptional tensile qualities, with five times the strength of steel of comparable quality and a density of only one-fifth that of steel. Furthermore, unlike steel, Kevlar does not corrode when exposed to air and water. Kevlar is now widely employed in a variety of applications, including boat hulls, airplanes, bicycle tires, military helmets, bulletproof jackets, and so on. Its principal flaw is that it decomposes slowly in an alkaline environment or when exposed to chlorine or UV light.
In a variety of applications, Kevlar materials with functional surfaces can provide significant performance benefits. For Kevlar materials, Alfa Chemistry may provide functionalized surface coating services. Using our comprehensive and simple variety of surface coating methods, you can change the surface attributes of practically any Kevlar-related product. If you choose to work with us, you can confidently change the finish of your product!
Alfa Chemistry provides customers with a number of polymer surface modification technologies for modifying the surface of Kevlar materials to improve their varied surface qualities. Our surface modification technology options include but are not limited to the following.
These nanoscale coatings can be manufactured and are chemically stable, optically transparent, and highly durable.
Case 1: Carbon nanotube coating for enhanced friction and impact properties of Kevlar
Personnel survivability and agility can be improved by reducing the weight of protective equipment while maintaining or enhancing the amount of ballistic protection. Energy dissipation and impact performance are heavily influenced by sliding and friction between strands. Many researchers have experimented with changing the friction of fibers and yarns to increase the performance of protective fabrics.
Fig 1. SEM micrographs showing MWNTs coating the surface of Kevlar fibers at varying levels of magnification. a) MWNT agglomerates and coating on the surface of several Kevlar fibers, b) view of a single fiber surface showing coverage of Kevlar with MWNTs, c) close-up views, and d edge view of MWNTs on the fiber surface. (LaBarre E. D, et al. 2015)
Kevlar fibers swell in MWNT suspensions, resulting in reinforced fibers with improved mechanical properties. Multi-walled carbon nanotubes (MWNT) have much higher strength and modulus than Kevlar fibers, and the swelling of Kevlar fibers in MWNT suspensions results in reinforced fibers with improved mechanical properties. Alfa Chemistry used ultrasonication to modify Kevlar yarns and fabrics in N-methyl pyrrolidone (NMP) and MWNT solutions. This method has the ability to improve the fiber's intrinsic qualities while also increasing friction.
The yarn modulus increased by 15% and the static and dynamic friction coefficients increased by 30% in tensile, static friction, and pull-out tests. Draw-out tests on yarn revealed a 230 percent increase in the force needed to pull the yarn out. Low-velocity impact testing revealed that MWNT-treated Kevlar's ballistic limit rose by around 50% with a negligible bulk increase. The observed changes in fabric reaction show that MWNT treatment has the potential to improve the fabric's ballistic limit by boosting interfilament and inter-yarn friction while reducing fiber strength and bulk.
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