Swelling behavior of PDMS-PMHS pervaporation membranes in ethyl acetate-water mixtures

Self-Assembly of Self-Cleaning Polystyrene/Styrene-Butadiene-Styrene Films with Well-Ordered Micro-Structures

Well-ordered porous films have been widely applied in various areas, such as chemical sensors, microreactors, and tissue engineering. In this article, we propose a novel air-liquid interface self-assembly method to fabricate well-ordered porous polystyrene (PS)/styrene–butadiene–styrene (SBS) films by simply dipping the PS/SBS chloroform solutions onto the surface of a mixed water/ethanol liquid phase. The proper volume ratio of water/ethanol is necessary for the formation of films with highly uniform pore size. The effect of weight ratio of PS/SBS, the volume ratio of water/ethanol and the concentration of the solutions were experimentally investigated. The pore size decreases with the concentration of polymer solution, and the structure becomes more regular with the decrease of water/ethanol volume ratio. Ordered structure can be formed under PS/SBS in a certain weight ratio. The self-assembled films also have the function of self-cleaning. Besides the analysis of structural characteristic, the self-assembly mechanism was also discussed.

Removal of hazardous chlorinated VOCs from aqueous solutions using novel ZSM-5 loaded PDMS/PVDF composite membrane consisting of three hydrophobic layers

Hydrophobic polymer possesses significant potential for selective separation of volatile organic compounds (VOCs) from their aqueous solutions by pervaporation (PV). In the present study mixed matrix hydrophobic membranes of polydimethylsiloxane (PDMS) supported on polyvinylidenefluoride (PVDF) substrate were synthesized by incorporating hydrophobic inorganic ZSM-5 filler. The indigenous membranes were crosslinked with tetraethylorthosilicate (TEOS) for the extraction of volatile chlorinated hydrocarbons such as dichloromethane (DCM), trichloromethane (TCM), 1,2-dichloroethane (DCE), and 1,1,2,2-tetrachloroethane (TeCE), which pose serious environment threat and health hazard. Thermal stability, crosslinking, crystallinity, surface morphology and swelling characteristics of the indigenously developed membranes were determined by TGA, FTIR, XRD, SEM and sorption studies, respectively. Effect of operating parameters such as feed composition and filler concentration on separation performance in terms of flux and selectivity were determined. Flux of DCM, TCM, DCE and TeCE was found to be 0.166, 0.146, 0.141 and 0.06 kg m(-2)h(-1) with selectivity of 541, 1068, 917 and 15,000, respectively, for 20% ZSM-5 filled PDMS membrane for aqueous feeds containing 1.33% (w/v) DCM, 0.8% (w/v) TCM, 0.84% (w/v) DCE and 0.28% (w/v) TeCE in water. The membrane exhibited considerable feasibility for scale-up with significant potential for removal of hazardous chlorinated VOCs from aqueous solutions.