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Characterization of morphology and d...

Zhang, Jinghui.

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Characterization of morphology and diffusion in perfluorosulfonate ionomer and diffusion of penetrants in heterogeneous polymer systems: An NMR approach.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Characterization of morphology and diffusion in perfluorosulfonate ionomer and diffusion of penetrants in heterogeneous polymer systems: An NMR approach./
Author:	Zhang, Jinghui.
Description:	185 p.
Notes:	Adviser: Alan A. Jones.
Contained By:	Dissertation Abstracts International67-03B.
Subject:	Chemistry, Physical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3209386
ISBN:	9780542578144

Characterization of morphology and diffusion in perfluorosulfonate ionomer and diffusion of penetrants in heterogeneous polymer systems: An NMR approach.
Zhang, Jinghui.

Characterization of morphology and diffusion in perfluorosulfonate ionomer and diffusion of penetrants in heterogeneous polymer systems: An NMR approach. - 185 p.

Adviser: Alan A. Jones.

Thesis (Ph.D.)--Clark University, 2006.

The morphological structure of the perfluorosulfonate ionomer Nafion (Dupont trademark) and the transport of ions and low molecular weight compounds through this polymer have been the subject of many investigations. In this thesis, pulse field gradient and spin diffusion NMR are used to study the structure and mobility of the penetrants in Nafion. With increasing concentration of DMMP the pendant domain becomes larger in volume fraction while the backbone domain remains constant. When the pendent group plus DMMP phase becomes the majority of the system, unusual change in the spin diffusion indicating the presence of a second, larger pendant groups domain develop while the smaller domain similar in size to that present in dry Nafion also persists. The results of pulse field diffusion experiments also indicate a rapid rise in translational mobility of the DMMP in the same concentration range which reflects that the space accessible to DMMP is better interconnected in the larger domain morphology.

ISBN: 9780542578144Subjects--Topical Terms:

560527
Chemistry, Physical.

Characterization of morphology and diffusion in perfluorosulfonate ionomer and diffusion of penetrants in heterogeneous polymer systems: An NMR approach.
LDR:03320nam 2200313 a 45 001 965396
005 20110906
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020 $a 9780542578144
035 $a (UMI)AAI3209386
035 $a AAI3209386
040 $a UMI $c UMI
100 1 $a Zhang, Jinghui. $3 1288172
245 1 0 $a Characterization of morphology and diffusion in perfluorosulfonate ionomer and diffusion of penetrants in heterogeneous polymer systems: An NMR approach.
300 $a 185 p.
500 $a Adviser: Alan A. Jones.
500 $a Source: Dissertation Abstracts International, Volume: 67-03, Section: B, page: 1464.
502 $a Thesis (Ph.D.)--Clark University, 2006.
520 $a The morphological structure of the perfluorosulfonate ionomer Nafion (Dupont trademark) and the transport of ions and low molecular weight compounds through this polymer have been the subject of many investigations. In this thesis, pulse field gradient and spin diffusion NMR are used to study the structure and mobility of the penetrants in Nafion. With increasing concentration of DMMP the pendant domain becomes larger in volume fraction while the backbone domain remains constant. When the pendent group plus DMMP phase becomes the majority of the system, unusual change in the spin diffusion indicating the presence of a second, larger pendant groups domain develop while the smaller domain similar in size to that present in dry Nafion also persists. The results of pulse field diffusion experiments also indicate a rapid rise in translational mobility of the DMMP in the same concentration range which reflects that the space accessible to DMMP is better interconnected in the larger domain morphology.
520 $a Proton and sodium-23 spectra are reported on acid and sodium neutralized forms of the perfluorosulfonate ionomer (Nafion) respectively. This local structure view is compared with pulse field gradient diffusion measurements of water, methanol and dimethyl methylphosphonate(DMMP) in several Nafion films. Both the proton and sodium-23 spectra indicate that the counter ions are primarily in clusters or aggregates with no evidence for isolated ions. The greatest tortuosity is observed for DMMP in cast films with added nanoparticles and this is an improvement in terms of potential applications of Nafion in chemical protection.
520 $a Another high permeability fluoropolymer without ionic groups is also characterized. The diffusion of pentane and propane in TFE/PDD copolymer is studied using pulse field gradient NMR as a function of time after sample preparation. Diffusion became more rapid after a few weeks which was ascribed to conditioning by the penetrant.
520 $a To understand diffusion in heterogeneous systems a two-domain lattice model is developed based on a model by Ediger. The simulation results are compared with the effective medium theory and simple models for tortuous and restricted diffusion. All the comparisons match. In addition, the diffusion simulation can successfully simulate experimental results.
590 $a School code: 0048.
650 4 $a Chemistry, Physical. $3 560527
650 4 $a Chemistry, Polymer. $3 1018428
690 $a 0494
690 $a 0495
710 2 0 $a Clark University. $3 1017690
773 0 $t Dissertation Abstracts International $g 67-03B.
790 $a 0048
790 1 0 $a Jones, Alan A., $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3209386