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A PFG-NMR Study of Restricted Diffusion in Heterogeneous Polymer Particles

✍ Scribed by John Georg Seland; Matteo Ottaviani; Bjørn Hafskjold

Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
216 KB
Volume
239
Category
Article
ISSN
0021-9797

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✦ Synopsis

The diffusion resistance to monomers during heterogeneous polymerization of polyolefin particles may have a significant effect on the observed activity. This diffusivity is, in general, unknown. To gain more information on this diffusion resistance in such systems, PFG-NMR has been used to measure the diffusion of organic solvents in various systems of porous polymer particles. In such systems the complex morphology and geometry demands careful analysis of the PFG-NMR attenuation curve. In this study, effects from restricted diffusion, domains having different diffusivity, and internal magnetic field gradients are expected. Thus, the obtained diffusivities have to be considered carefully, and a way to analyze the data taking these effects into account is presented.

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