Papers by Keyword: Non-Solvent

Abstract: Asymmetric porous aluminium-oxide ceramic hollow fibre membranes have been prepared by the phase inversion / sintering technique. The effect of non-solvent such as ethanol, isopropanol and ethylene glycol monomethylether(2-methoxyethanol) on the geometry and performance of hollow fibres was investigated. Morphologies of Al2O3 ceramic hollow fibre membranes were characterized using a scanning electron microscope (SEM). The effective porosity and the mechanical strength were determined by Archimedes method, and three point method, respectively. The prepared Al2O3 hollow fibre membranes show the asymmetric structure with a finger-like layer and a sponge-like layer. The effective porosity of the prepared hollow fibre membranes exceeds 47%, and the bending strength of the hollow membranes exceeds 63 MPa. The Al2O3 hollow fibre membranes with moderate permeation characteristics for gas and pure water are prepared by the introduction of nonsolvent in membrane casting solution. The separation factors of H2 to N2 or CO2 of the hollow fibers with nonsolvent are over 2.0.

Abstract: In this work, polysulfone ultrafiltration membranes were prepared via simple phase inversion with distilled water as non-solvent additive. The main reason for the addition of water in polysulfone dope solution preparation was to enhance the membranes structure. In the dope, 15 wt. % of polysulfone was used and water was varied up to 6 wt. %. The effects of water on morphology, porosity and tensile properties were investigated in detail. From the porosity test, results showed that the addition of water has improved membrane porosity up to 53 %. The FESEM images revealed that membrane morphology has also been modified. However, the tensile properties of membrane decreased as water content increased which may be due to the porosity interaction between polysulfone/NMP with water.

Abstract: This study is to develop a novel method for preparation of the chitosan scaffold having interconnected open pore structure and controlled pore distribution. For this, the effects of addition of non-solvent on chitosan solution were estimated. The porous scaffolds were typically prepared by solid-liquid separation and subsequent sublimation of solvent. Alcohol was used as non-solvent for chitosan. The difference of freezing temperature of each of the components induced the liquidliquid and the liquid-solid phase separation via demixing solution (solvent/non-solvent/chitosan). The morphology, heterogeneous pore distribution and mechanical properties of the scaffolds were examined. The addition of non-solvent in chitosan solution was to make the controlled homogeneous micropores and improved interconnectivity between pores without any surface skin layer. For control chitosan scaffold, the pore size was mainly about 80~100 μm. On the contrary, Pore diameters could be controlled mainly within the range 30~100 μm, with a variation of solvent/non-solvent ratio. The number of minute pore (4~25 μm) over chitosan scaffold increased with increasing ratio of non-solvent. New prepared scaffold exhibited larger value of breaking elongation, more elasticity, but less tensile strength than that of control scaffold.