What are the types of aramid fibers?
There are two main types of aramid fibers based on the location of chemical bonds in the structure of aramid fibers i.e. Meta- aramid and Para-aramid. This meta and para refer to the location of chemical bonds.
• Meta- aramid:
In meta-aramid fibers, the chemical bonds are more aligned in the long direction of the fibers i.e the fibers are not aligned. In Fact, they form the zig-zag pattern. The fibers of meta-aramid have excellent thermal, chemical, and radiation resistance. The angle between the amide plane and the phenylene plane in meta-aromatic polyamide is 30 degrees that result in the most stable structure. In comparison to para- aramid, meta- aramid are soft and electrically conductive.
They are used to produce fire-retardant textiles such as outerwear for fire- fighters and racing car drivers. Some of the examples of meta- aramid fibers are Nomex and teijinconex.
• Para- aramid:
The fibers made from para- aramid polyamide are higher in strength in comparison to meta- aramid polyamide. A few of the applications of para- aramid fibers are for producing reinforcement plastics for civil engineering structures, Stress skin panels, and other high tensile strength applications. In comparison to meta- aramid, para- aramid are stiff, and have greater tenacity and strength. But, they are sensitive to chemicals and the presence of acids, alkalis, and bleaches degrades the strength of para- aramid polyamide.
Some of the examples of para- aramid fibers are Kevlar, Technora, Twaron, Heracron.