Solvent-resistant Membranes for Ultrafiltration

Poly(vinylidene fluoride) (PVDF) porous supports coated with cellulose [92] were commercialized by Dow (ETNA membranes). PVDF is soluble only in a few organic solvents such as dimethyl acetamide. Cellulose is very stable in organic and aqueous solvents. However, because of its low solubility, preparing cellulose membranes is not a trivial task. Stengaard [72] proposed the preparation of composite membranes by coating chlorotrifluoroethylene/vinylidene fluoride (CTFE/VF) or PVDF supports with hydroxyethylcellulose and hydroxypropylcel- 

A solvent-resistant membrane based on PAN was developed by Hicke et al. [93]. The membrane was prepared from poly(acrylonitrile-coglycidyl methacrylate). The membrane with defined epoxy content could be prepared by a conventional phase-inversion process and stabilized by a post-treatment with a solution containing about 25% ammonia. As a result of the ammoniolysis reaction, a crosslinked membrane with high solvent resistance was obtained. 

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