High-Pressure and High-Temperature NMR Observation of Synthetic Polymers: High-Resolution Measurement Taking Advantage of Motional Narrowing in Sub-Critical Fluids

Abstract

The solution-state NMR measurement of a synthetic polymer in sub-critical fluids has been accomplished by taking advantage of the specially-designed high-pressure and high-temperature NMR probe. The purpose here is to overcome the signal broadening typically occurring in conventional solution-state NMR due to the slow dynamics of polymers at room temperature. A remarkable sharpening of the ¹H NMR signal was observed for poly (N-vinyl-2-pyrrolidone) dissolved in D₂O at 250°C. This result has encouraged us to apply high-temperature NMR methods to polymers, such as copolymers, whose spectra were too complicated to be deconvoluted by means of conventional procedures.