Date of Award
M.S. in Engineering Science
Admicellar polymerization was developed in the 1980s as an economical method for modifying various surfaces. In admicellar polymerization, a low monomer to initiator (M/I) ratio was traditionally required to overcome this limitation and achieve high polymer conversion when oxygen was present in the headspace and dissolved in the reaction medium. To develop an environmentally friendly, cost-efficient, and feasible deoxygenation and initiation technique, we studied the use of glucose oxidase (GOx) in admicellar polymerization. In this method, GOx acts as the catalyst in the oxidation of ?-D-glucose, while consuming oxygen and generating hydrogen peroxide and D-glucono-?-lactone. There are many advantages of GOx to other deoxygenation techniques. First, GOx is produced in nature by various insects, plants, animals, and fungi; therefore, it is inexpensive and easily accessible. Also, this enzyme has shown persistent activity in aqueous and various organic solvents and has high thermal stability.We hypothesized that GOx can both deoxygenate and initiate the polymerization system. Deoxygenation occurs by the consumption of oxygen and the formed hydrogen peroxide will initiate the polymerization in the absence of a thermal initiator. We examined the ability of GOx to successfully deoxygenate and initiate the admicellar polymerization of styrene using hexadecyltrimethylammonium bromide (C16TAB) to form admicelles on the surface of silica particles. We compared the initiation performance of GOx to 4,4’-azobis(4-cyanovaleric acid) (V-501) and analyzed its deoxygenation ability compared to nitrogen-purged polymerizations. The study showed that when the solution was not shaken during the deoxygenation process via GOx, the initiation capacity of GOx was limited, and its corresponding apparent conversions were lower than V-501 initiated admicellar polymerization. However, shaking the vial while the deoxygenation occurs resulted in both a higher conversion and higher equilibrium rate when compared to the thermal-initiated polymerization. After shaking the solution, enzyme-initiated admicellar polymerization reached a final apparent conversion of ~86% after 6 hours. Further, GOx performed exceptionally well as an oxygen scavenger when added to a polymerization system with a thermal initiator present. Low concentrations of GOx ([GOx]=200 nM) were able to deoxygenate the reaction medium as well as nitrogen purging and showed similar apparent conversion data of approximately ~80%.
Shakeri, Elaheh, "Enzyme-Initiated Admicellar Polymerization" (2021). Electronic Theses and Dissertations. 2053.