Synthesis and Characterization of Biopolymer Composites and their Inorganic Hosts
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Date
2009-08-07
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Abstract
Biopolymers are biodegradable and biocompatible materials obtained from renewable sources. These polymers could have an increased impact in consumer or health applications, given a larger, more flexible range of physical properties. Targeting enhanced properties through the design of organic-inorganic hybrids requires novel synthesis routes. An in-situ polymer composite that differs from hybrids generated by simple mixing of the organic and inorganic phases, has been demonstrated here. A known ring opening polymerization catalyst was incorporated within the channels of mesoporous hosts (e.g. MCM-41). A combination of elemental, solid-state NMR, BET nitrogen adsorption, and microscopy experiments indicated that the stannous octoate catalyst was supported inside the host channels, and that a charged framework is not required for its incorporation. These Sn(Oct)2 supported mesoporous catalysts were used to prepare poly(d,l-lactide) composites. Multiple experiments, including solid state NMR, BET nitrogen adsorption, and calorimetric analysis, gave evidence that the resulting polymer forms inside the host channels. In this way, an organic-inorganic composite which grows out of the crystallites is generated in-situ. Additionally, the acid catalyzed condensation polymerization of lactic acid with micro/mesoporous materials was investigated. Results suggest that Al-SBA-15 is a potential catalyst for this type of polymerization. This approach is desirable, since the generated organic-inorganic composite would contain no impurities (i.e. metal catalysts).
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polylactide, ring opening polymerization, poly(lactic acid), mesopores, MCM-41, SBA-15, nanocomposites, NMR, biopolymers
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Degree
PhD
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Chemistry