The synthesis, characterization and antibacterial activity of quaternized poly(2,6-dimethyl-1,4-phenylene oxide)s modified with ammonium and phosphonium salts

A new class of antimicrobial polymers consisting of PPO (polyphenylene oxide) was synthesized, and the antimicrobial activities of these polymers were investigated. This was accomplished by selective α-bromination of PPO (BPPO) followed by quaternization reactions with various tertiary amines or phosphines. Two types of BPPO were prepared, and the antimicrobial activities of the quaternized polymers were tested against Gram-positive bacteria (S. Epidermidis) and Gram-negative bacteria (Escherichia. coli). The triphenylphosphonium-modified polymer showed excellent antibacterial activity against both types of bacteria. Generally, the thermal stability of phosphonium-modified BPPO was superior to that of the ammonium analog, and the increase in the functionalization of the polymer backbone resulted in improved antimicrobial activity.