Chitosan (CS) is a competitive material for pervaporation membranes due to its richness in natural resources and excellent hydrophilicity. However

the high crystallinity and intense hydrogen bond interactions endow CS with compact structure and low permeability

which has limited its application. To address this issue

CS was blended with polyether-polyamide block copolymer Pebax 1657 and coated on NaOH-hydrolyzed polyacrylonitrile (PAN) ultrafiltration substrates to fabricate composite membranes. The membranes were applied in pervaporative separation of water from ethanol

and were further applied in intensifying esterification of lactic acid and ethanol by pervaporation. NaOH-hydrolyzed PAN substrates showed an increased hydrophilicity

which was beneficial to the interfacial stability enhancement of the composite membranes. When blended with CS

the rigid polyamide segments could destruct the crystalline regions within CS

thus enable the increase in permeation flux; the hydrophilic and the flexible polyether segments could help to enhance the membrane selectivity. The optimal pervaporation performance in improving the yield of ethyl lactate were achieved when the mass ratio of CS to Pebax was 2:1

with a permeation flux of 703 g·m-2·h-1

and a separation factor of 308 (increased by 61% and 65% compared with CS control membrane

respectively)

while the yield of ethyl lactate (after 8 h of reaction) increased from 58% to 73%.