Highly efficient and antibacterial zinc norfloxacin thermal stabilizer for poly(vinyl chloride)

Abstract

A novel kind of highly efficient and antibacterial thermal stabilizer, zinc norfloxacin (Zn(C₁₆H₁₇FN₃O₃)₂·4H₂O, represented as ZnNo₂), for poly(vinyl chloride) (PVC) was first reported in this paper; the structure of which was characterized by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), elemental analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD) and laser particle size analysis. ZnNo₂ extended the thermal stability of PVC and had good synergetic effects with calcium stearate (CaSt₂) on decreasing the releasing rate of HCl from PVC, which were confirmed by the results of thermal stability research including the Congo red test, discoloration, dehydrochlorination test and visible spectroscopy. The thermal stability mechanism of ZnNo₂ and CaSt₂ on PVC was proposed in this paper. The best auxiliary thermal stabilizer was the compound of dibenzoylmethane (DBM), pentaerythritol (PET) and triphenylphosphate (TPP) for ZnNo₂/CaSt₂ with both acceptable initial color and long-term stability for PVC products. Importantly, the inhibition zone test showed that ZnNo₂ had good antibacterial activity against Escherichia coli and Staphylococcus aureus, even in PVC with low concentrations.