Aramid INDEX

The mechanical properties of paracrystalline aramides and other high-performance polymeric fibres are shown in Table 19.11. In comparison some other fibres are mentioned in this table (see also Sect. 13.6). Aramide fibres display a very high refractivity (refractive index and strong birefringence // 2.2, n 1.6). 

The high degree of aromaticity of these materials also provides significant flame resistance. All commereial aramids have a limited oxygen index in the range of 28-32%, which compares with 20% for aliphatic polyamides (Table 13.2). The utilization of these properties is discussed in greater detail in the Applications section of this chapter. 

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