posted on 2020-03-23, 14:35authored byCuong N. Hoang, Yen H. Dang, Chi T. Pham, DongQuy Hoang
Bis(2-aminoethyl)terephthalamide,
an amide-containing diamine,
was obtained from the aminolysis of waste poly(ethylene terephthalate)
bottles. This diamine reacts with various aromatic dianhydrides to
form novel polyamideimides (PAIs). The formation of amic acid or ammonium
carboxylate salt intermediates depends strongly on the substituents
of the dianhydrides. The electron-withdrawing substituents promote
the creation of an ammonium carboxylate salt, whereas the electron
donors assist with the amic acid intermediate formation. These salts
and amic acids were further converted into polyimides by thermal treatment.
The structures of the intermediates and PAIs were characterized by
Fourier transform infrared, 1H nuclear magnetic resonance
(NMR), and 13C NMR spectroscopies, and their thermal properties
were determined by differential scanning calorimetry and thermogravimetry.
X-ray diffraction patterns and inherent viscosity values of these
PAIs were also reported. By using these chemical transformations,
waste poly(ethylene terephthalate) bottles were converted into high-performance
PAIs. These PAIs can be used as membrane-modifying agents for industrial
separation applications.