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Characterization of the Micellar Structure of a Barium Nonylphenolate/Barium Carbonate Complexby Nuclear Magnetic Resonance Spectroscopy
Biing-Ming Su*
Akzo Nobel Chemicals Inc., Dobbs Ferry, New York 10522
ABSTRACT: The micellar structure of a barium nonylpheno-late/barium carbonate complex was characterized by 1H and
13C nuclear magnetic resonance (NMR) spectroscopy. Several NMR techniques, including measurement of spin-lattice relaxation time, chemical shift variation, and line width of the 1H
NMR signal and solid-state 13C NMR data, were used in this study. NMR results indicate that the prepared barium nonylphenolate and barium carbonate complex formed a micelle structure with the oxygen atom of the nonylphenolate ring oriented toward the solid-state center core of barium carbonate while the highly branched aliphatic chain pointed outward to the hydrocarbon solvent.
Paper no. S1277 in JSD 5, 6164 (January 2002).
KEY WORDS: Correlation time, CPMAS (cross-polarization magic-angle spinning), micelle, NMR (nuclear magnetic resonance), PTFE [poly(tetrauoroethylene)], spin-lattice relaxation time, surfactant.
Nonylphenol is one of the more common surfactant raw materials used in the detergent industry. As a solubilizer or emulsifier, it can form micelle-type structures with certain cations under the right conditions. These structures are mixed metal liquids that result in colloidal microemulsions in oil. They have been widely used as a heat stabilizers in the PVC industry. The shelf stability of these liquid stabilizers for PVC is related to the size of the microdroplet. Several papers have been published (1,2) in which dynamic light scattering was used to determine the size of the microemulsion microdroplets for the systems of barium nonylphenate complex, barium carboxylate complex, and calcium carboxylate complex. Many nuclear magnetic resonance (NMR) techniques have also been published and applied to the characterization of the micellar structure of different surfactants (3,4). In this study, both 1H and 13C NMR spectroscopy were utilized to study the micellar structure of a barium nonylphenolate/barium carbonate complex. 1H
and 13C NMR relaxation times, the line width, and chemical shift change of 1H NMR signal and solid-state 13C NMR MAS and CPMAS spectra were used to gain information about the structure and mobility of the micelle.
EXPERIMENTAL PROCEDURES
Materials. The barium nonylphenolate/barium carbonate complex dissolved in hydrocarbon solvent and nonylphenol samples was provided by Akcros Chemicals America (New Brunswick, NJ).
NMR sample preparation. Nonylphenol and barium nonylphenolate/barium carbonate...