Metal‐containing polyureas containing ionic linkages in the main chain can be obtained by the polyaddition reactions of 2,4‐tolylene diisocyanate with mixtures of divalent metal salts of sulfanilic acid (p‐aniline sulfonic acid [ASA] ) and 4,4′‐diaminodiphenylmethane. Ba, Zn, Pb, and Sr were used as divalent metals, and their structures were characterized by 1H‐NMR, 13C‐NMR, and IR. The polyureas were obtained with ASA(M) up to 100% in feed diamines and they were all soluble in DMF and DMSO. The inherent viscosity of the polyureas decreased markedly with an increase in metal content. The thermal properties of these polyureas were also investigated by DSC and TG. It was found that introducing the metal into the polyurea increased the thermal stability.
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Qiu et al. (1993) studied this question.
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