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SYNTHESIS AND CHARACTERIZATION OF POLYMERS WHICH MIMIC THE FUNCTIONS OF HEMOGLOBIN (HEME, VINYL, OXYGEN CARRIER)
Abstract
The objective of this dissertation was the synthesis of a water soluble vinyl polymer which could model some of the properties of hemoglobin such as oxygen and carbon dioxide carrying capacity, hydrophobic domains and rigidity. The selection and synthesis of functional monomers was very important in the development of a model of hemoglobin. Derivatives of hemin, dimethylester (HDME), di-3-(1-imidazolyl)propylamide (HDA) and mono-3-(1-imidazolyl)-propylamide monomethylester (HMEMA), were synthesized to function as oxygen carriers. The bulk of the polymer was poly(styrene) whose function was to provide hydrophobic domains. Three monomers, methyl p-vinylbenzenesulfonate (MSS), 4-vinylpyridine (4VP) and p-vinylbenzylchloride (VBC), were incorporated in the polymer at 13 - 20 mol % and gave water solubility subsequent to hydrolysis of the ester, quaternization of the amine or substitution of the chlorine with a trialkylamine respectively. p-Azidophenyl methacrylate (APMA), a photoactive crosslinking agent, was polymerized to give structural rigidity. Amine moieties, 2-aminoethyl methacrylate (AEMA) and N-methacrylylhexamethylenediamine (NAHD) were incorporated to carry carbon dioxide as a function of pH. The reactivity of these monomers was characterized and the reactivity ratios were utilized to prepare ter- and tetrapolymers of known composition. Heme monomers behaved as chain terminators except in the presence of strong ligands for iron. Polymeric subsets of the five different types of monomers were characterized as simple models of hemoglobin. The kinetics of the oxygenation of HMEMA showed that oxidation is due to dimerization. Polymer bound HMEMA was 1.5 times more stable to dimerization but also exhibited some autooxidation. ('13)C-NMR experiments, used to study the formation of carbamate as a function of pH in amine-containing polymers, proved that the pK(,a) of the amines was too high to bind ('13)CO(,2) at physiological pH. Dye solubilization experiments demonstrated the presence of hydrophobic domains in the model polymers which were favored at high hydrophobe content and ionic strength and low solution concentration. These polymer molecules aggregated in solution at concentrations greater than 0.1 - 0.2 weight %. Preliminary evidence suggested that photolysis of APMA caused intramolecular crosslinking of the polymer. Novel hydrophobic polyampholyte gels were observed in polymers containing hydrophobic, anionic and cationic groups.
Subject Area
Polymers
Recommended Citation
FINKENAUR, AMY LEE, "SYNTHESIS AND CHARACTERIZATION OF POLYMERS WHICH MIMIC THE FUNCTIONS OF HEMOGLOBIN (HEME, VINYL, OXYGEN CARRIER)" (1984). Doctoral Dissertations Available from Proquest. AAI8410283.
https://scholarworks.umass.edu/dissertations/AAI8410283