Influence of acetylation degree of cellulose acetate on pervaporation properties for MeOH/MTBE mixture

The pervaporation separation of the MeOH/MTBE mixture was performed with th ree cellulose acetate membranes under various feed compositions and operati on temperatures. The results show that the acetylation degree has great inf luence on the pervaporation properties because the quantity of hydroxyl gro ups in the polymer matrix leads to different crystallinty degrees. The diff erent extent of the plasticization effect resulted in membranes performing their special flux trend and selectivity over the range of feed composition s and caused the permeants to transport through the membrane in different d iffusion modes under various operation temperatures. The IR sorption spectr a evidenced that for membranes with different acetylation degrees there exi sted different sorption sites for penetrants and provided a proof for diffe rent pervaporation properties of the tested membranes. (C)2000 Elsevier Sci ence B.V. All rights reserved.