An aliphatic type of Hyperbranched Polyester(HBPE) was synthesized from 2,2-dihydroxymethyl propanyl acid(DMPA) and 1,1,1-trihydroxymethyl propane(TMP) via Pseudo-One-Step method,and employed to improve the pervaporation properties of Ethyl Cellulose(EC) membrane on Benzene/Cyclohexane separation.The permeate flux of membrane was enhanced greatly with the similar separation factor,when moderate amount of HBPE was added into EC membrane.The sorption properties of EC-HBPE and EC membranes were investigated.The results indicate that,the sorption selectivity of EC membrane dosn′t changed significantly,but the sorption amount at equilibrium for EC-HBPE is elevated in the case of the content of G4HBPE in EC is 20%(mass fraction),and all membranes show more preferential toward Benzene than Cyclohexane.The total permeate flux of EC-G4HBPE membrane increases from 14 kg/um·m2·h of EC to 34 kg/um·m2·h,and the separation factor from 3.25 of EC to 3.73 for a binary mixture containing 10% Benzene at 40 ℃.

Pervaporation membranes containing hyperbranched polymer were prepared from the blends of ethyl cellulose (EC) and hyperbranched polyester (HBPE). The FT-IR analysis indicated that the interactions between EC and HBPE decreased as increasing the generation of HBPE. The membrane containing HBPE (EC-HBPE) showed both higher sorption ratio and selectivity than pure EC membrane. The effects of HBPE content as well as temperature of feed solutions on the membrane performance were investigated in detail. The EC-HBPE membrane exhibited much higher permeate flux than the EC membrane, while the separation factor maintained at same level.

An aliphatic type of hyperbranched-polyester (HBPE) that was synthesized from 2,2-dihydroxymethyl propanyl acid (DMPA) and 1,1,1-trihydroxymethyl propane (TMP) was end-capped with acrylic group, and the photo-polymerizable hyperbranched-polyester (AHBPE) was obtained. These AHBPEs were employed as the macromolecular crosslinking agents to enhance the pervaporation performance of EC membrane for the separation of benzene/cyclohexane mixtures. The effects of the content of AHBPE and benzophenone (BP) as well as the radiating time on the separation factor and the total permeate flux were investigated in detail. The results show that, the performance of EC membranes incorporating AHBPEs of higher generations exhibited much higher flux, with a comparison to the membranes modified by micromolecular crosslinking agent of ethylene glycol dimethacrylate (EGDM). The membrane with the total permeation flux of 42.5kgμmm−2h−1 and the separation factor of 6.82 was obtained at the AHBPE and BP content of 40wt% and 10wt%, respectively.