l-Lysine-derived optically active poly(hydrazide-imide)s: synthesis, characterization and their application in removal of heavy metal ions

Six novel poly(hydrazide-imide)s (PHIa–f) were prepared from the reaction of a novel l-lysine-derived chiral diacid, ethyl l-lysine-N,N’-ditrimellitoyl diacide (1), with six synthetic dihydrazides by solution polycondensation. These polymers have inherent viscosities in the range of 0.22–0.45 dl g−1, display optical activity, and are readily soluble in polar aprotic solvents. They start to decompose (T10%) above 248 °C and display glass-transition temperatures at 164.37–210.20 °C. All the above polymers were fully characterized by UV, FT-IR, and 1H NMR spectroscopy, TGA, DSC, inherent viscosity measurement and specific rotation.