New optically active and thermally stable poly(ester-imide)s containing bicyclo segment in the main chain: Synthesis and characterization

New optically active diacid containing L-2-aminobutyric acid moiety was prepared by reacting bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride 1 , with L-2-aminobutyric acid 2 in the acetic acid, and was polymerized with several aromatic diols 5a – f to obtain a new series of optically active poly(ester-imide)s (PEIs) through direct polycondensation using tosyl chloride/pyridine/ N , N -dimethylformamide system as condensation agent. The data obtained by these methods indicate that, good yields and inherent viscosities are resulted. These polymers are readily soluble in polar organic solvents such as N,N -dimethyacetamide, N,N -dimethyformamide, dimethyl sulfoxide. The obtained polymers were characterized by FTIR, specific rotation measurements, elemental analysis and 1 H NMR spectroscopy. The thermal stability of the resulting PEIs were evaluated with thermogravimetric analysis and differential scanning calorimetry techniques under a nitrogen atmosphere.