Doctoral Dissertations

Wuu-Yung Lin

Abstract

"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.

Advisor(s)

Blum, Frank D.

Committee Member(s)

Van-De-Mark, Michael R.
Ercal, Nuran
James, William Joseph
Morosoff, Nicholas

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Sponsor(s)

United States. Office of Naval Research
National Science Foundation (U.S.)

Comments

Financial support of the National Science Foundation under grant DMR-9600926

Publisher

University of Missouri--Rolla

Publication Date

Spring 1997

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

Pagination

xii, 167 pages

Note about bibliography

Includes bibliographical references (pages 162-165).

Rights

© 1997 Wuu-Yung Lin, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

Glass transition temperatureNuclear magnetic resonanceDeuteriumSilicates

Thesis Number

T 7249

Print OCLC #

39635208

Electronic OCLC #

905225513

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