Aminolysis of poly(ethylene terephthalate) waste with ethylenediamine and characterization of α,ω-diamine products

Bis(2-aminoethyl) terephthalamide (BAET, or trimer) and α,ω-aminoligo(ethylene terephthalamide) (AOET, or oligomers) were obtained from the reaction of poly(ethylene terephthalate) (PET) waste with excess amount of ethylenediamine (EDA). The structures of trimer BAET and oligomers AOET were confirmed by FTIR, NMR, HPLC-MS analysis. The influence of input molar ratio of reactants on oligomer yield was also investigated. The formation of oligomers competed with the formation of trimer even though EDA was used in excess amount. The melting points, thermal properties of BAET and AOET were determined by DSC, TGA techniques. The physical melting process and chemical transamidation of amino end capped BAET/AOET occurred concurrently before thermal decomposition.