Obtenção e caracterização de membranas compósitas de película fina (PEUAPM/quitosana e PEUAPM/quitosana/argila esmectítica

Abstract

Polymeric membranes produced from Ultra High Molecular Weight Polyethylene (UHMWPE), under controlled conditions, can act as separation membranes, however, studies have shown that their selectivity needs to be improved. However, there are very few studies that seek to fill this gap, that is, an improvement of this property (selectivity) in this type of membrane. Usually existing studies use aggressive solvents or complex techniques. The objective of this work was to prepare polymer membranes by the incipient melting method (sintering) and composite membranes by deposition of diluted solution (chitosan or bionanocomposite). Polymer membranes (UHMWPE) were produced under fixed conditions of time and temperature (60 minutes and 120°C). In the sequence, the polymer membranes were oxidized with 30% hydrogen peroxide (H2O2). Then, the chitosan or bionanocomposite chitosan/clay film was deposited. The obtained membranes were characterized by X-ray diffractometry (XRD), Infrared Region Spectroscopy (IR), Scanning Electron Microscopy (SEM), Contact Angle Testing and Bubble Point Testing. And evaluated in water permeation tests under Temperature conditions of 27°C and 0,25 bar. Membrane diffractograms showed that after oxidation with H2O2 and chitosan or bionanocomposite deposition, there were no changes in the structure of the UHMWPE, but changes in its crystallinity were observed. The spectra obtained by IV showed the presence of bands related to the oxidation of UHMWPE and its interaction with chitosan or bionanocomposite. The polymer membranes showed a heterogeneous surface with large and small pores and the composite membranes showed uniform and flat surfaces, with no detectable pores, visualized by MEV. The membranes oxidized with H2O2 and modified with chitosan or bionanocomposite showed changes in the morphology, hydrophilicity and pore diameter. The water permeation experiments revealed that the performance of the polymer membrane oxidized with H2O2 was superior to the performance of the polymeric membrane UHMWPE.