Characterization of PVC-based polymer inclusion membranes with phosphonium ionic liquids

Abstract

Abstract Membrane techniques can be used to separate different compounds, i.e., toxic metal ions from waste waters. As any other method of separation, also this one, based on polymer inclusion membranes (PIMs), has certain limitations. One of them is the stability of membranes. In the present paper, the dependence of the physical and chemical properties on composition of PVC-based polymer inclusion membranes doped with phosphonium ionic liquids (CYPHOS IL 101, CYPHOS IL 104, CYPHOS IL 105 and CYPHOS IL 109) was studied. The thermal stability of investigated membranes was examined by thermogravimetry together with differential thermogravimetry analysis. Obtained results showed that studied PIMs are stable to the temperature of about 170 °C. The membrane morphology was examined by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, as well as scanning electron microscopy (SEM). The visibility of all characteristic bands in the ATR-FTIR spectra confirmed the presence of individual components in the membranes: a polymer, a plasticizer and the carriers. It also suggested that there were no signs of the covalent bond formation between the polymer, the plasticizer and the carrier. Only van der Waals or hydrogen bonds could be present. Moreover, in the SEM images of the investigated PIMs a rough surface without pores was observed.