NMR Spectroscopic Characterization of a Series of New Polyamide-Imides
Polyamide-imides occupy an important position among the class of thermally stable polymers. The objective of this investigation deals with the complete characterization by nuclear magnetic resonance (NMR) spectroscopy of six new polyamide-imide polymers. These polymers have been prepared from N,N′-bis(chlorocarbonylmethyl)benzophenetetracarboxylic diimide with aromatic diamines. All of the diamines contain aromatic ether linkages. Polymerization takes place at room temperature in dimethylacetamide to yield the six new polymers. These polymers are soluble in dimethyl sulfoxide (DMSO) at room temperature to such an extent that solution NMR analysis is feasible. The use of NMR spectroscopy for polymer characterization offers a simple, convenient and rapid method of analysis. Complete characterization of these polymers is necessary to define a known set of standards. Preliminary analysis of the proton and carbon-13 NMR spectra indicated a need for further information to make complete assignments. A distortion-less enhancement by polarization transfer (DEPT) experiment was run to determine the multiplicities of the carbons. The use of the two dimensional FT-NMR techniques homonuclear correlation (COSY) and heteronuclear correlation (HETCOR) was also necessary to make assignments.