Preparation And Properties Of Star PEO Film Materials And Their Composite Films

Poly (ethylene oxide) (PEO) has high CO2 permeability and high CO2/light gases solubility selectivity. Ether oxygen groups in PEO has strong interactions with CO2 molecule, which were found to provide high solubility selectivity for CO2. The flexible nature of ether oxygen linkages in polymers contributes to the formation of low glass transition temperature, highly mobile rubbery materials exhibit high gas diffusivity, which also contributes to high gas permeability.In this work, series of cross-linked PEO membranes had been prepared by photopolymerization of prepolymer solutions containing poly (ethylene glycol) methyl ether acrylate (PEGMEA) used as monomer, dipentaerythritol pentaacrylate (DPPA) and dipentaerythritol hexaacrylate (DPHA) used as crosslinker, respectively. The physical properties of membranes were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Wide angle X-ray diffraction (WAXD), et al., the permeation properties were tested by gas permeability tester, to attempt to decide the optimum composition for polymerization. Results indicated, DPPA/PEGMEA-20 (DPPA/PEGMEA=20:80) membrane reached a highest CO2 permeability coefficient of 681.50 Barrer with CO2/N2 selectivity of 45.01, CO2/CH4 selectivity of 12.74, CO2/H2 selectivity of 8.95 at 0.2 MPa and 35℃, DPHA/PEGMEA-3 (DPHA/PEGMEA=3:97) membrane reached a highest CO2 permeability coefficient of 1110.89 Barrer with CO2/N2 selectivity of 42.84, CO2/CH4 selectivity of 13.30 and CO2/H2 selectivity of 10.93 at 0.2 MPa and 35 ℃ and the CO2/N2 separation performances of these two membranes were above the upper bound.On one hand, DPPA/PEGMA-20 (DPPA/PEGMEA=20:80) was chosen as the optimum composition for DPPA/PEGMA. The influence of the composition of the solution on the common substrate membrane was studied by adding ethyl acetate and changing the crosslinker. Results indicated, the common substrate membrane could not be used as substrate membrane. On the other hand, different kinds of PEGDA membranes were prepared and the permeance was tested. DPHA/PEGMA-3 (DPHA/PEGMEA=3:97) was chosed as the optimum composition for DPHA/PEGMA. The composite membranes were prepared by photopolymerization after coating by DPHA/PEGMEA-3 used as coating solution, PEGDA/PEG400(70/30) used as support, and investigated the permeation property of composite membrane. Results indicated that Com- PEGDA/PEG400(70/30) had the 2061.21 GPU of CO2 peameance with CO2/N2 selectivity of 39.22.