"Crosslinking of aerogels is a promising approach to combine the advantages of inorganic and polymeric materials. In the present study, two types of polyimide-silica hybrid aerogels, APTES-BTDA-MDA (mol ratio: 2:2:1) and APTES-BTDA-MDA (mol ratio: 2:3:2), were synthesized using a sol-gel process followed by heating in order to imidize the polyamic acid that is formed quickly and is covalently bonded to silica. The hybrid aerogels were made using 3-aminopropyltriethoxysilane (APTES) endcapped polyamic acids and tetramethoxysilane (TMOS) as precursors. Polyimide crosslinked aerogels were characterized by TGA, SEM, FT-IR, BET, solid state NMR and gas pycnometry. These hybrid aerogels exhibit high thermal stability and have potential applications in thermal insulation. Silica-polymethylmethacrylate (PMMA) composites have been synthesized by in situ polymerization of methylmethacrylate (MMA) in the microstructure of silica gels by using an alkoxy derivative of 2,2 '-azo-bis (isobutyronitrile) already bonded to silica. Composites with three different silica contents were synthesized and their thermal and mechanical properties were compared to neat PMMA and a composite prepared via mechanical dispersion of sol-gel silica nanoparticles in PMMA. Silica-PMMA composites were characterized by TGA, FT-IR, compression testing and solid state NMR. The PMMA composites exhibited considerable rise in thermal decomposition temperatures as compared to neat PMMA"--Abstract, page iv.
Isaac, Kakkattukuzhy M.
M.S. in Chemistry
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- In situ polymerization of aminopropyltriethoxy-silane-endcapped polyamic acid on the micro-structure of base-catalyzed silica aerogels to derive polyimide crosslinked silica aerogels with improved thermal stability.
- Synthesis of compact silica-PMMA composites by in situ polymerization of methyl methacrylate in the void space of mesoporous silica by employing an alkoxy derivative of the 2,2'-azobis(isobutyro-nitrile) free radical initiator covalently bonded to the silica surface
xii, 43 pages
© 2008 Vishal U. Patil, All rights reserved.
Thesis - Open Access
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Link to Catalog Record
Patil, Vishal U., "Polymer reinforced aerogels and composites A. Polyimide crosslinked aerogels B. Silica-polymethylmethacrylate composites" (2008). Masters Theses. 5416.