Eckelt, J., Wolf, B. A.
"Membranes directly prepared from solutions of native cellulose"
Macromolecular Chemistry and Physics 2005, 206, 227-232.
Abstract: Starting from 5 wt.-% solutions of a prehydrolysis kraft pulp ((M) over bar (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 CO2 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.
preprint number: 257