Amorphous glassy polyamide

Let us consider in the present chapter conclusion the fractal analysis of amorphous glassy polyamide (phenylone) and particulate-filled nanocomposites on its basis fracture in compression tests. The experimental data show that elastic bodies can be destroyed by brittle mode at compression. In addition the fracture has often columnar character and body division on vertical columns is formed by cracks, propagating in uniaxial compression... 

This is used when polymers are readily melted without degradation and the molten polymer is forced through a spiimeret comprising 50 to 1000 fine holes. On emerging from the holes, the threads sohdify, often in an amorphous glassy state, and are wound into a yam. Orientation and crystallinity are important requirements in fibers, and the yam is subjected to a drawing procedure that orients the chains and strengthens the fiber. This technique is applied to polyesters, polyamides, and polyolefins. 

Copolymers of high Tg but which are amorphous and thus glassy (the glass-clear polyamides ). 

The stress-strain curve in Fig. 7.24b first of all exhibits elastic and preplastic behaviour. It then reaches a maximum whose sharpness depends on the polymer and also the deformation rate. Beyond this point, the stress remains almost constant over a certain region, before suddenly increasing to fracture. This is brittle fracture, perpendicular to the load. Many semi-crystalline polymers, such as polyethylene, polypropylene, polyamide 6 and polyamide 6,6 exhibit this type of behaviour at ambient temperature. However, among amorphous polymers in the glassy state, polycarbonate is one of the rare examples to behave in this way. 

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