The chemistry of automotive coatings has undergone tremendous changes over the past twenty years in response to environmental pressures to reduce the volatile organic content (VOC) and an increase in consumer expectations for appearance and durability of the finish. Furthermore, the use of organic pigments is increasing in today's coatings due to environmental, health, and durability issues. Significant overlap now exists between the molecular weights of modern coating components and the mass range amenable to Fourier transform mass spectrometry (FTMS). One popular approach to lowering the VOC is the use of high solids (>70%) low-molecular-weight (<5000 Daltons) enamels.1 However, structural imperfections in the organic molecules used in high solids formulations have a more profound impact on final properties than do imperfections in their low solids high-molecular-weight predecessors, therefore sophisticated analytical techniques are required. For polymers, soft ionization methods using CO2 laser desorption or electrospray ionization afford both the chain length distribution and the chemical composition at every chain length. Gel permeation chromatography can be coupled to FTMS through an electrospray ionization interface to characterize telechelic polymers.2 Using quadrupolar axialization and collisional cooling, high resolutions are possible for end group determinations. Tandem MS studies performed on polymer molecular ions provide information about the specific architecture and functionality location. Using CO2 laser desorption molecular ions are furnished for organic pigments contained in cross-linked colorcoats.
 K. Adamsons, G. Blackman, B. Gregorovich, L. Lin, R. R. Matheson, Progress in Org. Coatings, 34, 1998, 64.
 B. P. Devlin, T. R. Darling, C. T. Berge, M. J. Darmon, M. C. Grady, J. E. Hansen, W. J. Simonsick, R. R. Matheson, L. L. Litty, D. A. Paquet, L. Wilczek, A. Gridnev; Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.), 38 (1), 1997, 458.
Dr. William J. Simonsick, Jr. is a research associate with the Performance Coatings Business of DuPont. Bill received his Ph.D. in analytical/environmental chemistry in 1985 from Indiana University, Bloomington, Indiana, and his B.S. from Seton Hall University, South Orange, New Jersey in 1981. His current research interests include polymer characterization using soft ionization techniques in mass spectrometry and pyrolysis methods. Bill has also coupled powerful separation techniques (supercritical fluid extraction/chromatography, gel permeation chromatography) with mass spectrometry for polymer characterization. Bill holds one patent and has over seventy publications in these areas.
This page has been accessed
times since 9/15 /96 .
Last Updated Saturday, January 16, 1999 07:37:25