Macromolecular Rapid Communications, Vol.29, No.4, 293-298, 2008
A precursor route to supramolecular oligo(p-phenylene terephthalamide) block copolymers
New soluble precursors for the step-wise synthesis of oligo(p-phenylene terephthalamide) block copolymers are described. Kevlar-like aramide oligomers up to the hexamer (six phenyl groups) were prepared in a polymer-analogous manner. Activating the carboxylic-acid-carrying oligomers as carbonyl chlorides while reversibly transforming the aromatic amides into imidoyl chlorides gave access to soluble precursors. The dimer and tetramer precursor were prepared and used in block copolymer synthesis. Single-crystal XRD confirmed the structure of the dimer precursor. Above a critical rod length, the Kevlar-like rod-coil block copolymers show strong aggregation in non-polar solvents such as chloroform.