Syntheses and properties of halato‐telechelic polyurethane‐ureas from divalent metal salts of p‐aminobenzoic acid, diamine, dialkylene glycols, and diisocyanate

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Abstract
Halato‐telechelic polyurethane‐ureas were synthesized from divalent metal salts of p‐aminobenzoic acid, 4,4′‐diaminodiphenylmethane (4,4′‐methylenedianiline, MDA), dialkylene glycols, and 2,4‐toluylene diisocyanate (TDI). As the divalent metal, Mg and Ca were used, and diethylene glycol and dipropylene glycol were the glycols used. The halatotelechelic polyurethane‐ureas obtained showed better solubilities in dimethylformamide (DMF) and dimethylsulfoxide (DMSO) than previously reported halato‐telechelic polyureas from the metal salts, MDA, and TDI. The reduced viscosities of the polyurethane‐ureas in DMF and DMSO were very low at very low concentrations but increased as the concentration increased. The increase was higher in DMF having lower dielectric constant, due to lower depression of ionic association. Introducing the metal into the urethane‐urea backbone resulted in a considerable decrease in decomposition temperature. In dynamic mechanical property measurements, they exhibited no sharp decrease in relative shear modulus and no peak of tan δ, probably due to aggregation of ionic groups in the polymer main chain.