Doctoral Dissertations

Abstract

"The synthesis and characterization of composites comprised of poly(methyl acrylate) (PMA) covalently grafted to modified silica was performed with special emphasis on the study of the glass-transition (Tg) behavior of the composites. Surface modification of silica, resulted in the covalent attachment of a silane initiator molecule (that can initiate Atom Transfer Radical Polymerization, ATRP) on the silica-surface. The modified silica was used as the macroinitiator for ATRP of methyl acrylate, to graft PMA chains covalently to silica. The characterization of the grafted PMA-silica composites was carried out using thermogravimetric analysis (TGA), Fourier transform infra-red spectroscopy, (FTIR), modulated differential scanning calorimetry (MDSC), and nuclear magnetic resonance (NMR) spectroscopy. At low grafted amounts (ca. 10 to 27 wt% PMA), it was observed that the covalent attachment of the PMA chains onto the silica-surface significantly restricted the segmental mobility of the PMA chains and increased the Tg. The Tg-behavior of the covalently grafted composites was compared to that of composites made by physically adsorbing PMA onto the silica-surface. At high grafted amounts (80 to 90 wt % PMA), the Tg-behavior of the grafted composite was similar to that of the physically adsorbed composite. The Tg-behavior of copolymers and blends comprised of PMA and acrylic isobutyl polyhedral oligomeric silsesquioxane (POSS) macromers was also studied. For the copolymers, the incorporation of the POSS resulted in effective reinforcement, while for the blends, the reinforcement due to POSS was non-uniform and apparently localized"--Abstract, page iv.

Advisor(s)

Blum, Frank D.

Committee Member(s)

Switzer, Jay A., 1950-
Stoffer, James O.
Reddy, Prakash
Sitton, Oliver C., 1951-

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Sponsor(s)

Missouri University of Science and Technology. Chemistry Department
Missouri University of Science and Technology. Materials Research Center

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2009

Journal article titles appearing in thesis/dissertation

  • Glass transition behavior of poly(methyl acrylate) grafted to silica by surface-initiated ATRP
  • Effect of Cab-O-Sil on the glass-transition behavior of composites of Cab-O-Sil with poly(methyl acrylate)
  • Copolymers and blends from methyl acrylate and acrylic isobutyl POSS nanomaterials

Pagination

xii, 153 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2009 Manikantan Balakrishnan Nair, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

Polymeric compositesSilica -- SurfacesGlass transition temperature

Thesis Number

T 10235

Print OCLC #

862972189

Electronic OCLC #

905905850

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