Influence of type of uniform aromatic amide units on segmented copolyetheresteramides

Segmented copolymers with aromatic bisesterdiamides of uniform length and poly(tetramethyleneoxide) (PTMO) soft segments were synthesized. The following aromatic diamines were used for the bisesterdiamides: p-phenylenediamine, o-tolidine, 4,4′-diaminodiphenylmethane and m-phenylenediamine. The concentration of the bisesterdiamide unit the copolymer ranged from 14 to 19 wt%, depending on the type of bisesterdiamide. The amount of solvent (NMP) needed for the solution/melt polymerization is reduced in this direction. Copolymers with a bisesterdiamide based on p-phenylenediamine are fast crystallizing and the bisesterdiamide crystallize nearly completely. As a result, the glass transition temperature is low (−65°C), the melting temperature high is (190°C) and the rubbery plateau is temperature independent. By lowering the structural regularity of the aromatic diamine, the melting temperature and crystallinity were reduced, however, the elasticity increased. In the rubbery modulus–elasticity relationship the type of uniform aromatic bisesterdiamide had little effect. Apart from the polymer based on p-phenylenediamine, the polymers were transparent.