ALTERNATING POLYESTERAMIDES BASED ON 1,4-BUTYLENE TEREPHTHALAMIDE .2.ALTERNATING POLYESTERAMIDES BASED ON A SINGLE, LINEAR DIOL (4NTM)

Strictly alternating polyesteramides consisting of 1,4-butylene tereph thalamide and aliphatic diols have been synthesized in the melt in the presence of a titanium catalyst. The influence of diol length on the thermal and mechanical properties was studied. Depending on its struct ure, the diol took part in the crystallization. All polymers crystalli zed very fast (T-m - T-c < 33 degrees) and had a lamellar structure. T he melting and glass transition temperatures decreased with increasing diol length, and both showed an odd-even effect. The polyesteramides were melt processed and their mechanical properties were determined us ing torsional (d.m.t.a.) and tensile tests. The polymers have a high g lass transition temperature. The polyesteramides have a flexural modul us close to those of polyamides (2.9 GPa), whereas the water absorptio n is close to the values of polyesters (1.6 wt%). Loss of the alternat ing structure of the polymers, caused by ester-amide interchange react ions, was studied through C-13 n.m.r. It was found that the melting an d glass transition temperatures decreased with increasing loss of unif ormity. (C) 1997 Elsevier Science Ltd.