ZIGZAG POLYAMIDES COMPRISING RODLIKE SEGMENTS CONNECTED BY FREELY ROTATING OR STIFF JOINTS

Six fully aromatic zigzag polyamides were synthesized and characterized. The angles between their rigid rodlike segments are all fixed at 119 degree and 120 degree . Three of the polyamides have joints between the rodlike segments with free torsional rotation, and three have rather stiff joints. In solution and the amorphous bulk they all adopt a random coil configuration. The behavior of all polymers in dilute solution is dictated by their equilibrium rigidity, with no significant difference between those having freely rotating joints and those having stiff joints. With increased concentration effects of kinetic rigidity become more prominent because the slowness or rapidity of torsional motion interferes in varying degrees with the free movement of interpenetrated coils and their segments. Two groups of radii of gyration were measured in dilute solution for all polymers.