Optics vertex 70 spectrometer

Epoxidized Soybean Oil (ESO) was obtained from Sankim (İstanbul, Turkey), maleic anhydride (MA), 2-chloroethanol (CE), 4-(dimethylamino)pyridine (DMAP), zinc chloride, hydroquinone, styrene (ST), sodium iodide, tetrahydrofuran (THF), triethylamine (TEA) were purchased from Merck (Darmstadt, Germany). All of these chemicals were used without any further purification. FTIR spectra of the compounds and copolymers were performed by Bruker Optics Vertex 70 spectrometer using ATR (attenuated total reflection) techniques from 4000 cm⁻¹ to 400 cm⁻¹. ¹H NMR spectra were acquired by a Varian Unity Inova 500 NMR spectrometer in CDCl₃. Thermal stabilities of the material were found by Shimadzu DTG 60 model TGA instrument with a 10 °C/min heating rate under nitrogen atmosphere. Differential scanning calorimetric (DSC) analyses of the copolymers were performed with a heat-flux type DSC instrument (SII Nanotechnology, ExStar 6200).

As an example of spectroscopic detection of changes occurring during membrane operation, we provide attenuated total reflection Fourier transform infrared spectra of MK-40 membrane and two series of membranes produced by the similar technique that operated in electrodialysis of mixed solution (15 mM NaCl and 7.5 mM CaCl₂) for 50 h in under-limiting current mode (approximately 0.5 theoretical limiting values calculated by the approach described in [60 (link)]). Membrane preparation and operation are described in [21 (link)]; in brief, the membranes were also based on MK-40 and underwent surface homogenization with LF-4SC layer and layer-by layer absorption of three layers total: two of polyamine (polyallylamine orpolyethylenimine, depending on series) and one middle layer of sodium polystyrene sulfonate (purchased from Merck KGaA, Darmstadt, Germany). The ATR-FTIR spectra were registered by the “Diagnostics of structure and properties of nanomaterials” Centre for Collective Use of Kuban State University using a Bruker Optics Vertex 70 spectrometer (Bruker, Billerica, MA, USA) for newly prepared membranes and for membranes after operation under current; the measurement were made for dry membranes.