A NOVEL METHOD FOR (13)C-NMR SPECTROSCOPY OF POLYMER IN EMULSION: QUANTITATIVE ANALYSIS OF MICROSTRUCTURE OF CROSSLINKED POLYBUTADIENE IN LATEX

A novel analytical method using high resolution (13)C-NMR spectroscopy to study polymer latex, which is a heterogeneous system comprising polymer dispersoid and water, is described. The appropriate concentrations of surfactant and dried rubber content of a polybutadicne latex, which give the best spectrum. were found to be 1 w/v% and 10%, respectively. The half-widths of resonance peaks for the latex sample were almost identical to the hall-widths obtained in solution, which were about one-third the width of those obtained using a solid sample of either a crosslinked or soluble polybutadiene. Nevertheless, the signal to noise ratio for the latex sample was slightly smaller than that for the solution sample. The values of spin-lattice relaxation time, T(1) , for the latex sample were similar to those for the solid sample. These demonstrate that the latex state (13)C-NMRspectroscopy will be a powerful technique for structural characterization of crosslinked gels in the dispersoid because it gives a high resolution spectrum comparable to solution state spectroscopy, showing short T(1) values corresponding to those for solid slate (13)C-NMR spectroscopy. High resolution latex state (13)C-NMRspeclroscopy was used to detcrnnine the concentrations of the various isomers of the polybuladiene in the dispersoid.