ABSTRACT
Since the 1970s, interest has grown enormously in heat-resistant, rigid-chain polymers for application in extreme environments. Kevlar [1] is the most successful example, followed later by poly(aryl ether ketone)s such as poly(ether ether ketone) (PEEK) [2]. In order to improve the processability of such aromatic polymers, it is common practice to decrease their melting points either by the introduction of defects or by the insertion of aliphatic units along the chains. Moreover, such polymers are receiving growing attention as molecular reinforcement in classical thermoplastics. With such an approach, blends are prepared by mixing the rigid polymer with the flexible one in a common solvent at a critical concentration, followed by coagulation in a nonsolvent, normally under spinning conditions. The mechanical properties of these systems depend mainly on the state of dispersion of the rigid-rod component in the flexible coil matrix [3-6].
