Structure and properties of p-aramid fibers

In this subsection the physicochemical and mechanical properties of the most common p-aramid brands will be discussed. It is worth noting that mostly p-aramids are used for reinforcement of thermoset and thermoplastic polymer matrices where strength and stiffness are critical. However, in the case of elastomer-based composites where more important are the flame resistance, flexibility and the resistance to thermal, impulse and vibrational stresses, the m-aramid fiber reinforcement renders superior properties [3]. 

Material Density Tensile strength Young s modulus Ductility Melting temp. 

The main advantage of the mechanical properties of Kevlar PPTA over its main competitors the glass and carbon fibers is the superior specific strength, related to its low density. 

As mentioned above, the manufactming process leaves aramid fibers with a skin/core structure, reflected in the model of Morgan et al [32]. Apparently, the coagulation creates a differential in density, voidage and fibrillar orientation along the fiber cross section. The fiber surface cools more rapidly, and this, combined with the effects of solvent evaporation, leaves a skin layer with an average thickness between 0.1-0.6 pm, having low 

Other attempts to enhance lateral interactions via interchain interaction rely on the addition of copol5rmer imits able of hydrogen bond formation in two directions rather than on changing the p ol5rmer backbone chemistry. The most successful attempt at present 

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