A novel method for 13{sup left}C-NMR spectroscopy of polymer in emulsion: quantitative analysis of microstructure of crosslinked polybutadiene in latex

摘要

A novel analytical method using high resolution 13{left sup}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 polybutadiene latex, which give the best spectrum, were found to he I w/v % and 10%, respectively. The half-widths of resonance peaks for the latex sample were almost identical to the half-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{sub}1, for the latex sample were similar to those for the solid sample. These demonstrate that the latex state 13{left sup}C-NMR spectroscopy 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{sub}1 values corresponding to those for solid state 13{left sup}C-NMR spectroscopy. High resolution latex state 13{left sup}C-NMR spectroscopy was used to determine the concentrations of the various isomers of the polybutadiene in the dispersoid.