Preparation and Characterization of Antibacterial Polycarbonate (PC) Using High Thermal Resistant Quaternary Fluoroalkyl Phosphonium Salts as Antibacterial Agents

Abstract

In our previous study, quaternary fluoroalkyl phosphonium salt with iodine anion (PPICF-13) was synthesized as an antibacterial agent for PC, but it would dye PC to be brown during processing because of the oxidation of the iodine. With the aim to eliminate the dyeing problem, three quaternary fluoroalkyl phosphonium salts (PPCF) with trifluoroacetate (TFA-PPCF-13), tetrafluoroborate (FB-PPCF-13), and trifluoromethanesulfonate (TFMS-PPCF-13) were synthesized in the research described here through anion exchange reactions between PPICF-13 with the relative silver salts. After evaluation of their antibacterial activity and thermal stability, FB-PPCF-13 was chosen to prepare antibacterial PC through injection processing. The influence of FB-PPCF-13 concentration on the mechanical properties, thermodynamic properties, light transmittance, appearance, and antibacterial activity of the antibacterial PC was investigated. The results showed that incorporation of FB-PPCF-13 had no negative influence on the mechanical properties of PC, but could reduce Tg and increase the MFI due to the plasticization effect of FB-PPCF-13. When the concentration of FB-PPCF-13 was 2 wt.% or more, the resulting antibacterial PC could have strong antibacterial activity no matter before or after being aged. Though FB-PPCF-13 reduced the light transmittance of PC, it did not influence the color scheme of dyed PC products.