Synthesis of alternating semi-aromatic poly(ester amide)s and the amide transesterification

In this work, a novel poly(ester amide)s (PEAs) was designed and synthesized from dimethyl terephthalate (DMT), 3-amino-1-propanol (AP) and adipic acid (AA). Firstly, the aromatic diol monomer (BHTT) was synthesized by DMT and AP, it was characterized by 1H NMR, 13C NMR, FT-IR and DSC, respectively. Then, the BHTT and AA were used to synthesize the semi-aromatic PEAs with alternating structure by melt polymerization. The effects of polymerization temperature and time on the crystallization, thermal stability and amide transesterification of PEAs were fully investigated. It was found that the prepared PEAs are semi-crystalline polymer with melting point around 154–165 °C and decomposition temperature around 377–392 °C. Most important, the chemical structure of PEAs synthesized under different conditions was explored by 1H NMR, 13C NMR and DEPT spectra, which confirms the occurrence of amide transesterification during the melt polymerization process.