Ultrahigh Modulus Rods of Wholly-Aromatic Copoly (ester-amide)

Uniaxially drawn rods were prepared by extensionally drawing the nematic melts of a wholly aromatic copoly (ester -amide) containing 6-hydroxy 2-naphthoic acid, p-amino phenol, and terephthalic acid, extruded from a die of 7mm diameter. The extrusion temperature was varied from 300 to 325°C. At each temperature the degree of molecular orientation in the drawn rods was varied by taking the extension ratio as a variable. The moduli decreased with increasing the diameter of the drawn rods, while the degree of crystallite orientation remained almost unchanged. Ultrahigh modulus values can be reached in highly oriented noncrystalline chains. The rods of 1.0mm diameter yielded ultrahigh moduli of 110 GPa for stretching and of 108 GPa for bending.