Synthesis and characterization of random poly(amide-sulfonamide)s: 3. Copolymers from two diamino monomers

Four new series of poly(amide-sulfonamide)s (PASAs), having different ratios of two different diamino monomer moieties in the polymer backbone, were obtained by low-temperature solution polycondensation of the respective diamines with terephthaloyl chloride/isophthaloyl chloride. With the exception of the most highly symmetric polymer series, all of the other polymers were readily soluble in aprotic polar solvents such as N,N-dimethylacetamide, dimethylformamide and dimethyl sulfoxide. The three series of soluble polymers had intrinsic viscosities in the ranges 0.51-0.72, 0.33-0.49 and 0.70-0.92 dl g^-1. Differential scanning calorimetry showed these PASAs to have glass transition temperatures greater than 250°C. Thermogravimetric analysis of the polymers showed moderate thermal stabilities, with 10% weight losses being recorded over the range 382-408°C. X-ray diffraction studies indicated that some of these polymers possess a certain degree of crystallinity.