Divinyl benzene cross-linked HTPB-based polyurethaneurea membranes for separation of p-/o-xylene mixtures by pervaporation

摘要

Cross-linked hydroxy terminated polybutadiene (HTPB)-based polyurethaneurea (PU), HTPB-divinyl benzene (DVB)-PU, was synthesized by a three-step polymerization process. It was first used as membrane material to separate p-/o-xylene mixtures by pervaporation (PV). The effects of the content of cross-linker DVB, feed concentration, and operating temperature on the PV performance of HTPB-DVB-PU membranes were investigated. The membranes demonstrated p-xylene permselectivity as well as high total flux. The introduction of DVB significantly enhanced the temperature resistance ability of the HTPB-DVB-PU membranes. With increasing DVB content, the separation factor increased while the total flux decreased a little. The highest separation factor reaches 2.01 and the total flux is 33 g/m~2h with feed concentration of 10 wt % p-xylene at 30°C. These PV performances with increasing DVB content were explained in terms of the view point of chemical compositions and physical structures of the HTPB-DVB-PU membranes.