The purpose of this research is to prepare and characterize poly(Beta-L-Malic acid) and its benzyl ester derivative from the intermediate optically active malolactone. The polymer prepared from the racemic malolactone will be investigated and its physical properties compared to the optically active poly(malic acid). The starting compounds for the lactone synthesis will be the racemic and optically active malic acid (L-form). They are readily available in both optical forms and the L-malic acid is a naturally occurring product. Polymerization of the benzyl ester of the optically active lactone will be carried out using selected anionic and cationic initiators. The reaction mechanism will be studied, with particular emphasis on the stereochemistry of the polymerization reaction and the physical properties of the isolated polymers. Future work will include the determination of the effect of stereoregularity on biological activity, biocompatibility and biodegradability of the polymers. The synthetic goals of the thesis are to obtain polymers having greater than 90% isotactic configuration (corresponding to greater than 90% optical purity of the lactone) and having a molecular weight in the range 10,000-20,000. The polymerization conditions, specifically the temperature, solvent and monomer/initiator concentrations ratio, will be varied to determine the effects on the polymerization kinetics and ultimately the molecular weights. Modifications of the polymerization conditions affected overall yield of isolated polymer. However, they seem to cause no effect on the molecular weight of the polymer. Varying the initiator, polymerization temperature, and solvent gave polymers with different molecular weight distributions (MWD) and yields but had no effect on the number average molecular weight (Mn). Differential scanning calorimetry and optical rotary dispersion spectroscopy demonstrated that the polymer possesses excellent stereoregularity.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-5797 |
| Date | 01 January 1984 |
| Creators | WOJCIK, RONALD THOMAS |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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