Synthesis of star-shaped aromatic polyamides consisting of cyclosiloxane core

Star-shaped aromatic polyamides were prepared, in order to obtain soluble aromatic polyamides which exhibited similar physical properties to those of the ordinary linear polyamides. For this purpose, two kinds of core molecules consisting of tetracyclosiloxane with octaamino or octacarboxyl groups were prepared, and octa-armed star-shaped aromatic polyamides were synthesized by polycondensation of 4-aminobenzoic acid initiated at the amino or carboxyl groups of these core molecules. Then, the terminal amino and carboxyl groups of the star-shaped polymers were end-capped by the reaction with p-toluoyl chloride and p-toluidine, respectively. It was found that star shaped aromatic polyamides were soluble in dimethylsulphoxide (DMSO) and other aprotic polar solvents, and maintained the unique characteristics of linear aromatic polyamides such as thermal stability and crystallinity.