Rapid determination of comonomer content, crystallinity, and long spacing by multiple-pulse proton NMR in ethylene–vinyl alcohol copolymers
✍ Scribed by Ernesto Pérez; María L. Cerrada; David L. Vanderhart
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 145 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0887-6266
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✦ Synopsis
Capitalizing on the superior sensitivity of proton NMR, relatively rapid estimates of three parameters, namely, comonomer content, crystallinity, and long spacing, are determined for three ethylene/vinyl alcohol copolymers using solid-state proton NMR measurements. Multiple-pulse techniques are utilized (a) in conjunction with magic angle spinning for measuring comonomer content, (b) in conjunction with a T 1xz relaxation measurement for determining crystallinity, and (c) in conjunction with a T 1xz -based spin diffusion measurement for determining the long spacing. These three parameters, extracted from data collected in a total spectrometer time of about 20 min, are compared with similar parameters obtained using more conventional DSC, SAXS (including synchrotron), and solution-state NMR measurements. Agreement is found to be good.