Novel membranes made from a semi-interpenetrating polymer network for ethanol–ETBE separation by pervaporation
✍ Scribed by Quang-Trong Nguyen; Christian Léger; Philippe Billard; P. Lochon
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 117 KB
- Volume
- 8
- Category
- Article
- ISSN
- 1042-7147
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✦ Synopsis
The design of high-performance pervaporation membranes for the selective removal of ethanol from ethyl t-butyl ether (ETBE) was performed by using semi-interpenetrating polymer network (s-IPN) materials. The chosen linear polymer in the s-IPN was a cellulose ester, and the network was formed by photopolymerization of a dimethacrylate, or a dimethacrylate and one or two co-monomers.
Membranes with good mechanical properties and moderate to good selectivity were obtained. Large permeability increases without loss in selectivity were observed with s-IPN films formed by cellulose propionate or cellulose butyrate interpenetrated by a network of poly(ethyleneglycol dimethacrylate). The use of dimethacrylate with longer spacers of the poly(ethoxy) type in these materials further increased the permeability. The permeation flux of cellulose acetate-based membranes is improved only when a methacrylate with poly(ethoxy) side chains is incorporated in the network by copolymerization with the poly-(ethoxy)-type dimethacrylate.
When the poly(ethyleneglycol dimethacrylate) in cellulose butyratebased s-IPN films increases, the selectivity remains constant, while the film permeability goes through a maximum. The results are interpreted on the basis of a "plasticization" effect exerted on the linear polymer by interpenetrated networks composed of methacrylates with poly(ethoxy) chains. The resulting improved segment mobility favors the permeability at low network contents. The stability of s-IPN membranes in hot liquid mixtures was explained by extended entanglements of the linear polymer with the branches of the network meshes.