Characterization of unsaturated polyester and alkyd resins using one- and two-dimensional NMR spectroscopy

One- (1D) and two-dimensional (2D) H-1- and C-13-NMR spectroscopy was used to characterize polyester and alkyd resins used in the coatings industry. The wealth of chemical composition information of the H-1- and C-13-NMR 1D spectra of the resins is revealed through 2D NMR experiments that spread chemical shifts in two dimensions, thus facilitating the peak assignment of the various components of the resins. It is shown that the types of polyols, acids, and vegetable oils used to modify the resins can be efficiently traced by NMR spectroscopic techniques. Information on the quantitative composition of the resins and especially the abundance of unsaturated fatty acid double bonds, which influences resin dryability and hardness, can be easily extracted from the H-1-NMR spectra upon successful assignment. (C) 2003 Wiley Periodicals, Inc.