An improved process for polyvinylidene fluoride membrane preparation by using a water soluble diluent via thermally induced phase separation technique

Explorations of combined nonsolvent and thermally induced phase separation (N-TIPS) method for fabricating novel PVDF hollow fiber membranes using mixed diluents

“…The diluent induced the NIPS process by facilitating the solvent-nonsolvent exchange at the dope-coagulant interface. Similar attempts of using a water-soluble diluent (TIPS solvent) have been made in the past decades (approach 1 in Table 1) [5,15,[17][18][19][20]. However, the sole use of water-soluble diluent might steer the phase inversion to a NIPS-dominated N-TIPS process.…”

A Review on Porous Polymeric Membrane Preparation. Part I: Production Techniques with Polysulfone and Poly (Vinylidene Fluoride)

“…As a result, they obtained a thin skin layer or macrovoids near the top surface due to NIPS and smaller pores near the bottom surface due to TIPS. For PVDF membranes, Jung et al [160], Hassankiadeh et al [161], Xiao et al [162] and Wu and Sun [163], modified TIPS by using a water-soluble poor solvent (TIPS solvent) as the diluent. However, this method may form some undesired membrane morphology such as a dense layer with scarce pores caused by the fast outflow of diluents leading to high permeability loss [159,163,164].…”

“…For PVDF membranes, Jung et al [160], Hassankiadeh et al [161], Xiao et al [162] and Wu and Sun [163], modified TIPS by using a water-soluble poor solvent (TIPS solvent) as the diluent. However, this method may form some undesired membrane morphology such as a dense layer with scarce pores caused by the fast outflow of diluents leading to high permeability loss [159,163,164]. Conversely, the finger-like macrovoids in the bulk structure near the surface layer due to a large concentration gradient between the solvent and non-solvent [48,162] can significantly decrease the membranes mechanical properties [46,132].…”

Tamisolve® NxG as an Alternative Non-Toxic Solvent for the Preparation of Porous Poly (Vinylidene Fluoride) Membranes

“…Emerging organic solvents were explored for membrane production and the obtained preliminary results have shown as their use can really benefit the innovation sector [ 28 ]. Among them, methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate (Polarclean) [ 29 , 30 , 31 , 32 , 33 , 34 ] Cyrene™ [ 35 , 36 , 37 , 38 ], dimethyl isosorbide [ 39 ], triethyl phosphate [ 40 , 41 , 42 , 43 , 44 ], diethylene glycol monoethyl ether acetate [ 45 ], glycerol triacetate (triacetin) [ 46 ], acetyl tributyl citrate [ 47 ], triethylene glycol diacetate [ 48 ], acetyl triethyl citrate [ 47 ], triethyl citrate [ 47 ] were proposed as non-toxic solvents for poly(vinylidene fluoride) (PVDF) membrane production through phase inversion. Carner et al [ 38 ] reported the use of several greener solvents, including ethyl acetate, 2-methyltetrahydrofuran (2-methylTHF) and Cyrene™ for the preparation of polymer inclusion membranes.…”