Elucidation of the proton NMR spectrum of poly (propylene oxide) by two-dimensional J-resolved spectroscopy.

Proton NMR spectra of synthetic polymers are often complex due to extensive spectral overlap of multiplets with different chemical shifts. Two- dimensional J-resolved spectroscopy is applied to the separation of overlapping multiplets in the 500 MHz proton spectrum of poly(propylene oxide). Chemical shifts and homonuclear coupling constants are reported for protons in different stereochemical environments. These values are consistent with spectral parameters previously determined for selectively deuterated polymers. Proton chemical shifts in atactic poly(propylene oxide) are observed to be sensitive to triad stereosequences, but the homonuclear coupling constants for head-to-tail monomer units are the same regardless of stereosequence.