The Preparation of New Polystyrenic Onium and Substituted Poly(thionylphosphazene) Antimicrobials

Candidate: Rachele Carafa

Supervisors: Dr. Daniel Foucher and Dr. Andrew McWilliams

Abstract:

With increasing concern over antimicrobial resistance in bacteria, the synthesis of traditional and non-traditional antimicrobial polymers is of interest. This work is divided into three research foci: the first focuses on the preparation of new polystyrenic quaternary ammonium and phosphonium compounds that will be grafted to plastic surfaces using benzophenone as a tethering agent. Three quaternary styrenic polymers (4-6) and their respective random copolymers with styrene (7-9) were synthesized and grafted onto HDPE, where biological testing of coatings 4, 5 and 7 using the LDI protocol showed some bacterial reduction when the alkyl chain lengths were ≥ 4. The second focuses on synthesizing novel thionylphosphazene monomers and looking into greener polymerization routes. Two novel thionylphosphazene monomers were synthesized, and a greener polymerization route was obtained using Lewis acid-catalyzed microwave irradiation. The third involves undertaking DFT calculations of various cyclic thionylphosphazenes to study alternate polymerization routes of these compounds. Energy calculations showed the potential for substituted thionylphosphazenes with small substituents to ring-open under ambient temperature conditions with Lewis acid catalysts.