Characterisation of the solvent stability of polymeric nanofiltration membranes by measurement of contact angles and swelling

Solvent-induced swelling of membranes — Measurements and influence in nanofiltration

“…Over the region δ = 15.3-23. 6 MPa 0.5 the solvent polarity increases to induce progressively less swelling in the PDMS layer and at even greater values of δ the membrane swelling was reduced still further and reliable values were difficult to obtain. Corresponding results for the 80 kGy radiation, 2 μm membrane are also shown in Table 1 and Figure 3.…”

“…Using a radiation crosslinked PAN/PDMS composite membrane that incorporated a nominal 10 μm thick PDMS layer and solvents with a range of solubility parameter (δ) spanning 14-29 MPa 0.5 , the authors showed measurements of swelling for both pure solvents and solvent mixtures at pressures up to 2000 kPa. Some of these data were compared favourably (in terms of measurement standard deviation (SD)) with the more widely used method of Ho and Sirkar [2] where the weight difference between a dry and solvent impregnated polymer sample is determined; see [3][4][5] for applications of the technique and [6,7] for alternative swelling measurement techniques.…”

New experimental measurements of solvent induced swelling in nanofiltration membranes

“…It is clear, however, that swelling propensity with both solvents followed a similar form as pressure was increased. The degree of swelling was apparently affected from the onset with pressure and there was greater effect on swelling from (say) 0-10 bar than over the range [10][11][12][13][14][15][16][17][18][19][20] bar. This result is perhaps to be expected as polymer chains in the PDMS come ever closer together, however, the change in swelling with pressure is interesting in the wider context.…”

“…~300 % expansion). Geens et al [11] also showed significant swelling with a range of solvents where prior to testing the selective top layer from three hydrophilic polymer membranes was removed using liquid nitrogen. In contrast, Piccinini et al [12] describe an alternative, and relatively complex, technique where a quartz spring microbalance was used to simultaneously measure solubility, diffusion coefficient and swelling for a solvent/polymer combination of acetonitrile/polyetherurethane.…”

The influence of polarity on flux and rejection behaviour in solvent resistant nanofiltration—Experimental observations

“…Although the literature is by no means extensive, a number of researchers have investigated the nanofiltration of organic feeds containing alcohol. The majority have determined flux and/or rejection performance at the laboratory scale with relatively simple deadend permeation or stirred cell apparati in order to establish fundamental data, membrane stability and/or an insight into transport mechanisms [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Much of the work has focussed on the behaviour of pure components and whilst some workers have identified membrane swelling as an important Recent work by the authors in SRNF examined the flux behaviour of low polarity alkyl and aromatic solvents with radiation crosslinked polydimethylsiloxane (PDMS) membranes.…”