Membranes Directly Prepared from Solutions of Unsubstituted Cellulose

✍ Scribed by John Eckelt; Bernhard A. Wolf

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 146 KB
• Volume: 206
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200400366

✦ Synopsis

Abstract

Summary: Starting from 5 wt.‐% solutions of a prehydrolysis kraft pulp ($\overline M _{\rm n}$ = 135 kg · mol^−1^) in the mixed solvent (dimethylacetamide + 7 wt.‐% LiCl) we have prepared cellulose membranes on different supports according to the phase inversion process using above all acetone (AC) and 2‐propanol as precipitants. In this context we have studied the phase behavior of the quasiternary system (DMAc+LiCl)/AC/cellulose. The obtained membranes are mechanically stable and in their mechanical and separation properties on the whole comparable to membranes consisting of regenerated cellulose. With respect to gas separation the ideal selectivity of CO~2~ in combination with N~2~ and O~2~ turns out to be opposite for the present membranes as compared with that consisting of regenerated cellulose. Ultrafiltration experiments performed with aqueous solutions of polyethylene oxide differing widely in their molar mass resulted in cut‐off molecular weights ranging from 3 to 9 kg/mol.

GPC analysis of the retentate and permeate for a membrane on a non‐woven fabric using AC as precipitant.

magnified imageGPC analysis of the retentate and permeate for a membrane on a non‐woven fabric using AC as precipitant.