Tacticity measurement of polymethacrylate by peak-eliminated fourier-transform NMR

ArticleinJournal of Polymer Science Polymer Letters Edition 14(9):531-535 · September 1976with12 Reads
DOI: 10.1002/pol.1976.130140904

    Abstract

    A number of works have centered on the structural determinations of macromolecules by using Fourier-transform NMR. However, in the PMR study of large biological molecules there are a variety of problems owing to a large residual HDO peak. Recently, water-eliminated Fourier-transform (WEFT) NMR was developed to overcome these problems and was applied to the study of biological molecules. In the reported work, the principle of WEFT method was successfully applied to the analysis of the tacticity of poly(alkyl methacrylate). The spectra of syndiotactic PMMA were measured in toluene-d//8 at 110 degree C by a pulse sequence of (180 degree minus t minus 90 degree minus 10 sec)//4 at various values of t, and the triad tacticities were determined from the intensity measurements of the three alpha -methyl peaks. The results are tabulated. The tacticities of several poly(alkyl methacrylates) were successfully determined by the peak-elimination method, and the results are shown. Agreement between the observed and the calculated dyad tacticities also shows the accuracy of the measurements.