Effect of temperature and membrane preparation parameters on gas permeation properties of polymethacrylates

Guelmues, Serguel Acikalin
Yılmaz, Levent
Permeabilities of N-2, Ar, O-2, CO2, and H-2 gases in PEMA (Polyethylmethaerylate) membranes have been measured above and below glass transition in the temperature range of 25-70 degrees C. The permeabilities of the gases were observed increasing with temperature. Arrhenius plot of permeability versus temperature data showed that there is a slope discontinuity at near to T-g of PEMA. In addition, the effects of membrane preparation parameters by solvent casting method (percentage of polymer in solvent, annealing temperature, annealing time, evaporation temperature, and evaporation time) have been investigated by using homogenous dense membranes of PEMA. It is observed that membrane preparation parameters strongly affect the membrane performance and the reproducibility of the permeability measurements. On the other hand, the effect of polymer structure on membrane performance has been investigated. Comparison of the permeabilities of N-2, Ar, O-2, CO2, and H2 gases in PEMA and PMMA membranes shows that PMMA membranes have smaller permeabilities and higher selectivities than PEMA membranes because of their higher glass transition temperature, T-g. (c) 2007 Wiley Periodicals, Inc.


Synthesis and characterization of conducting copolymers of (S)-2-methylbutyl-2-(3-thienyl)acetate with pyrrole and thiophene
Levent, A; Toppare, Levent Kamil; Cianga, I; Yagci, Y (Wiley, 2003-05-30)
Polymerization of methylbutyl-2-(3-thienyl)-acetate (MBTA) was achieved by constant current electrolysis at low temperature. Subsequently, the syntheses of block copolymers of polyMBTA were accomplished in the presence of either pyrrole or thiophene by constant potential electrolysis. Moreover, the copolymer of MBTA with thiophene was obtained with constant potential electrolysis.
Analysis of the Raman Frequency Shifts for the Lattice Modes and Vibrons Related to the Thermodynamic Quantities in the eta Phase of Solid Nitrogen
Yurtseven, Hasan Hamit (Walter de Gruyter GmbH, 2013-08-01)
The thermodynamic quantities of the isothermal compressibility, thermal expansion and the specific heat are calculated here as a function of pressure by using the observed Raman frequencies of the lattice modes and vibrons in the. phase of solid nitrogen. The Pippard relations and their spectroscopic modifications are constructed, and the slope dP/dT is deduced from the Raman frequency shifts in this phase of N-2. It is shown that the thermodynamic quantities can be predicted from the Raman frequency shifts...
Analysis of the specific heat of p-azoxyanisole (PAA) near the phase transitions
Kilit, E.; Yurtseven, Hasan Hamit (Informa UK Limited, 2010-01-01)
The analysis of the experimental data for the specific heat Cp at various temperatures is given here near the nematic-isotropic liquid (TNI = 133.9 degrees C) and the solid-nematic (TSN = 117.6 degrees C) transitions in p-azoxyanisole (PAA). The analysis of the specific heat Cp is performed according to a simple power-law formula and a renormalisation-group expression. The values of the critical exponent are extracted above and below the transition temperatures of TNI and TSN for this liquid crystalline mat...
Calculation of the C-P-C-V as a function of temperature close to the melting point in benzene
Tari, O.; Yurtseven, Hasan Hamit (Informa UK Limited, 2018-01-01)
The temperature dependence of the C-P - C-V is calculated at constant pressures using the observed volume data from the literature for solid and liquid benzene near the melting point. Our calculated values are compared with some earlier treatments and we find that they disagree at constant pressures for the solid benzene, whereas for the liquid benzene agreement is reasonable in terms of the order of magnitude between our calculated C-P - C-V and those predicted from the Peng-Robinson equation of state. Our...
Calculation of the compressibility and heat capacity of ice I in the pre-melting region
Yurtseven, Hasan Hamit (Informa UK Limited, 2009-01-01)
The isothermal compressibility and the heat capacity are calculated here using the experimental data for the heat expansion of ice I in the pre-melting region. By analysing the data at various pressures, compressibility and the heat capacity are predicted as functions of temperature and pressure near the melting point (p(m) 202.4 MPa, T-m 252.3 K) in ice I. Our predicted compressibility and heat capacity exhibit anomalous behaviour as the heat expansion in the pre-melting region of ice I.
Citation Formats
S. A. Guelmues and L. Yılmaz, “Effect of temperature and membrane preparation parameters on gas permeation properties of polymethacrylates,” JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, pp. 3025–3033, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35380.