THE MECHANICAL PROPERTIES AND PERVAPORATION PERFORMANCES OF POLY (VINYL ALCOHOL)/ CELLULOSE NANOCOMPOSITE MEMBRANES

摘要

Novel Poly (vinyl alcohol) (PVA)/cellulose nanocomposite membranes were prepared, and characterized by scanning electron microscopy (SEM). The characterization results demonstrated that cellulose nanocrystal (NCC) particles dispersed homogeneously within the PVA matrix, which could be assigned to the hydrogen bonds formed between PVA and NCC. Moreover, the pervaporation performance of these membranes was investigated using the separation of ethanol–water mixture as model system. Flux of the nanocomposite membranes was lower than those observed for the plain PVA membrane, but selectivity improved considerably. Among all the prepared membranes, PVA/ NCC nanocomposite membrane containing 3 wt% NCC exhibited the best separation factor, whose ultimate separation factor was 170 for 90 wt% aqueous solution of ethanol at 80 °C . Flux increased with increasing amount of water in the feed, but selectivity decreased considerably. These results were attributed to the NCC particles in the PVA membrane as a result of change in the micromorphology of the nanocomposite membranes. Mechanical properties of the nanocomposite membranes were examined in relation to NCC content in the composite. Optimal NCC content in the composite was found to be 3 wt% in terms of its overall properties as compared to neat PVA film. With the addition of 3 wt% NCC to PVOH the ultimate tensile strength showed improvement compared to pure PVA. The PVA/NCC nanocomposite membrane had shown increases in elongation at low filler loadings.