Doctoral Dissertations

Abstract

"The effect of molecular mass on adsorbed poly(methyl methacrylate) (PMMA) on silica was determined using temperature-modulated differential scanning calorimetry (TMDSC). A two-component model, based on loosely-bound polymer (glass transition temperature, Tg, similar to that of bulk) and tightly-bound polymer (Tg higher than that of bulk) was used to interpret the thermograms. Similar amounts of tightly-bound polymer were found for 450 and 85 kDa PMMA (0.78 mg/m²), while the 32 kDa sample had a smaller amount (0.48mg/m²). A comparison of adsorbed PMMA, poly(vinyl acetate) (PVAc), and poly(methyl acrylate) (PMA) on silica was made using the same technique. The amounts of tightly-bound PMMA (0.78 mg/m²), PVAc (0.78 mg/m²), and PMA (0.72 mg/m²), adsorbed on silica surfaces did not differ much. The ratios of heat capacity increments of the loosely- and tightly-bound components (ΔCpA/ΔCpB) at Tg, indicating the relative mobility of the two components, were also estimated to be about 1.8.

The dynamics of the phenyl-deuterated plasticizer di(propylene glycol) dibenzoate in bulk and adsorbed PVAc on silica were probed using solid-state ²H NMR. The dynamics of this plasticizer in the plasticized-bulk polymer system were found to be heterogeneous. For adsorbed PVAc on silica, the dynamics of the plasticizer was found to be even more motionally heterogeneous than that observed in bulk samples. The NMR results provided solid evidence that, when there is only a small amount of adsorbed polymer (i.e., 0.8 mg/m²), the plasticizer has very little or almost no effect on the dynamics of that polymer. The plasticizer was observed to be effective at higher adsorbed amounts"--Abstract, page iv.

Advisor(s)

Blum, Frank D.

Committee Member(s)

Van-De-Mark, Michael R.
Reddy, Prakash
Ludlow, Douglas K.
Switzer, Jay A., 1950-

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Sponsor(s)

University of Missouri --Rolla. Materials Research Center
National Science Foundation (U.S.)

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2010

Journal article titles appearing in thesis/dissertation

  • Thermal analysis of adsorbed poly(methyl methacrylate) on silica: effect of molecular mass
  • Comparison of hydrogen-bonded polymers on silica using temperature-modulated differential scanning calorimetry
  • Dynamics of di(propylene glycol) dibenzoate-d₁₀ in poly(vinyl acetate) by solid-state ²H NMR
  • Dynamics of di(propylene glycol) dibenzoate-d₁₀ in adsorbed poly(vinyl acetate) by solid-state ²H NMR
  • Quantitative analysis of thermograms for adsorbed polymers on silica

Pagination

xv, 171 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2010 Boonta Hetayothin, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Glass transition temperaturePolymethylmethacrylateSilica -- SurfacesSurface chemistry

Thesis Number

T 9697

Print OCLC #

749992467

Electronic OCLC #

750001900

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Chemistry Commons

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