"Deuterium solid-state quadrupole-echo NMR techniques were used to probe the dynamics of bulk and silica-adsorbed poly(methyl acrylate)-d3 (PMAd3). The effects of surface coverage, molecular weight and overlayer materials on the dynamics were investigated. Bulk PMA-d3 with high molecular weight showed a collapse in the 2H NMR powder pattern corresponding to a sudden increase in motional rate at about 50 C(nmr Tg), 40 °C above the reported glass transition temperature.
Surface samples were prepared by adsorption of PMA-d3 onto silica. The NMR spectra were collected from surface species at the surface-air interface. The spectra consisted of different components. Some of the adsorbed material had an enhanced mobility attributed to segments near the air interface. The adsorbed PMA-d3 was more rigid as the surface coverage decreased. The effect of molecular weight was also studied. Bulk PMA-d3 with lower molecular weight was more mobile. In contrast, the adsorbed PMA-d3 with higher molecular weight was more mobile.
Composite samples were prepared by hot pressing a surface sample with hydrogenated polystyrene and PMA of different molecular weights as the overlayer. The composite samples were studied in the interfacial layer of PMA-d3 between the silica and overlayer. No material in any composite sample had enhanced mobility and the lower the mobility of the overlayer, the more restricted the adsorbed PMA-d3 layer was"--Abstract, page iv.
Blum, Frank D.
Van-De-Mark, Michael R.
James, William Joseph
Ph. D. in Chemistry
United States. Office of Naval Research
National Science Foundation (U.S.)
University of Missouri--Rolla
Journal article titles appearing in thesis/dissertation
- Segmental dynamics of adsorbed poly(methyl acrylate)-d₃: The effect of coverage
- Segmental dynamics of adsorbed poly(methyl acrylate)-d₃: The effect of molecular weight
- Segmental dynamics of bulk and adsorbed poly(methyl acrylate)-d₃ by deuterium NMR: The effect of polymer overlayers
- Segmental dynamics of silica-adsorbed poly(methyl acrylate)-d₃: The effect of switching solvents
xii, 167 pages
© 1997 Wuu-Yung Lin, All rights reserved.
Dissertation - Restricted Access
Library of Congress Subject Headings
Glass transition temperature
Nuclear magnetic resonance
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://laurel.lso.missouri.edu/record=b4063983~S5
Lin, Wuu-Yung, "Segmental dynamics in bulk and adsorbed poly(methyl acrylate)-d₃ by deuterium NMR" (1997). Doctoral Dissertations. 1244.
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