Structural characteristics and gas permeation properties of polydimethylsiloxane/poly(propylene oxide) urethane/urea bi-soft segment membranes

Polymer ◽  
2005 ◽  
Vol 46 (7) ◽  
pp. 2346-2353 ◽  
Author(s):  
Denise P. Queiroz ◽  
Maria Norberta de Pinho
Keyword(s):  
Propylene Oxide ◽  
Structural Characteristics ◽  
Soft Segment ◽  
Gas Permeation ◽  
Poly Propylene ◽  
Permeation Properties

scholarly journals Sorption/Diffusion Contributions to the Gas Permeation Properties of Bi-Soft Segment Polyurethane/Polycaprolactone Membranes for Membrane Blood Oxygenators

Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Tiago M. Eusébio ◽  
Ana Rita Martins ◽  
Gabriela Pon ◽  
Mónica Faria ◽  
Pedro Morgado ◽  
...  
Keyword(s):  
Steady State ◽  
Soft Segment ◽  
Time Lag ◽  
Transient State ◽  
Gas Permeation ◽  
Dominant Factor ◽  
Atmospheric Gases ◽  
Equilibrium Conditions ◽  
Permeability Coefficients ◽  
Permeation Properties

Due to their high hemocompatibility and gas permeation capacity, bi-soft segment polyurethane/polycaprolactone (PU/PCL) polymers are promising materials for use in membrane blood oxygenators. In this work, both nonporous symmetric and integral asymmetric PU/PCL membranes were synthesized, and the permeation properties of the atmospheric gases N2, O2, and CO2 through these membranes were experimentally determined using a new custom-built gas permeation apparatus. Permeate pressure vs. time curves were obtained at 37.0 °C and gas feed pressures up to 5 bar. Fluxes, permeances, and permeability coefficients were determined from the steady-state part of the curves, and the diffusion and sorption coefficients were estimated from the analysis of the transient state using the time-lag method. Independent measurements of the sorption coefficients of the three gases were performed, under equilibrium conditions, in order to validate the new setup and procedure. This work shows that the gas sorption in the PU/PCL polymers is the dominant factor for the permeation properties of the atmospheric gases in these membranes.

scholarly journals Structural characteristics and gas permeation properties of polynorbornenes with retained bicyclic structure

Polymer ◽  
2001 ◽  
Vol 42 (6) ◽  
pp. 2455-2462 ◽  
Author(s):  
Chun-tian Zhao ◽  
M. do Rosário Ribeiro ◽  
M.N. de Pinho ◽  
V.S. Subrahmanyam ◽  
C.L. Gil ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Gas Permeation ◽  
Bicyclic Structure ◽  
Permeation Properties

scholarly journals Impact of the poly(propylene oxide)-b-poly(dimethylsiloxane)-b-poly(propylene oxide) macrodiols on the surface related properties of polyurethane copolymers

2016 ◽  
Vol 70 (6) ◽  
pp. 725-738 ◽  
Author(s):  
Ivan Stefanovic ◽  
Dejan Godjevac ◽  
Milena Spírková ◽  
Petar Jovancic ◽  
Vele Tesevic ◽  
...  
Keyword(s):  
Propylene Oxide ◽  
Microphase Separation ◽  
Soft Segment ◽  
Thermoplastic Polyurethane ◽  
2D Nmr ◽  
Morphological Properties ◽  
2D Nmr Spectroscopy ◽  
Molecular Weights ◽  
Highly Hydrophobic ◽  
Poly Propylene

Segmented thermoplastic polyurethane copolymers (PURs) were synthesized using 4,4'-methylenediphenyl diisocyanate and 1,4-butanediol as the hard segment and ?,?-dihydroxy-poly(propylene oxide)-b-poly(dimethylsiloxane)-b-poly(propylene oxide) (PPO-PDMS) as the soft segment. The content of incorporated soft segments in PURs varied in the range from 40 to 90 wt.%. The structure, molecular weights and crystallinity of obtained copolymers were monitored by FTIR, 1H, 2D NMR spectroscopy, GPC and DSC analysis, respectively. Surface free energy analysis indicates the presence of hydrophobic (siloxane) groups on the surface, giving highly hydrophobic nature to the obtained PURs films. Water absorption measurements showed that the increase of the hydrophobic PPO-PDMS segment content, led to the decrease of percentage of absorbed water in copolymers. SEM and AFM analysis revealed that copolymers with lower content of PPO-PDMS segments have higher microphase separation between segments. The results obtained in this work indicate that synthesized PURs based on PPO-PDMS, demonstrated proper surface and morphological properties with a great potential for variety of applications such as hydrophobic coatings in biomedicine.

ATR−FTIR Studies of Poly(propylene oxide)/Polybutadiene Bi-Soft Segment Urethane/Urea Membranes

2003 ◽  
Vol 36 (11) ◽  
pp. 4195-4200 ◽  
Author(s):  
Denise P. Queiroz ◽  
Maria N. de Pinho ◽  
Cristina Dias
Keyword(s):  
Propylene Oxide ◽  
Soft Segment ◽  
Ftir Studies ◽  
Poly Propylene

Effect of soft segment molecular weight on tensile properties of poly(propylene oxide) based polyurethaneureas

Polymer ◽  
2012 ◽  
Vol 53 (21) ◽  
pp. 4614-4622 ◽  
Author(s):  
S. Piril Ertem ◽  
Emel Yilgor ◽  
Cagla Kosak ◽  
Garth L. Wilkes ◽  
Mingqiang Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Tensile Properties ◽  
Propylene Oxide ◽  
Soft Segment ◽  
Poly Propylene

scholarly journals Gas Permeation Properties of High-Silica CHA-Type Zeolite Membrane

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 249
Author(s):  
Yasuhisa Hasegawa ◽  
Chie Abe ◽  
Mayumi Natsui ◽  
Ayumi Ikeda
Keyword(s):  
Molecular Size ◽  
Gas Permeation ◽  
Zeolite Membrane ◽  
Type Zeolite ◽  
High Silica ◽  
Separation Of Co2 ◽  
Α Al2o3 ◽  
Separation Performances ◽  
Molecular Sieving ◽  
Permeation Properties

The polycrystalline CHA-type zeolite layer with Si/Al = 18 was formed on the porous α-Al2O3 tube in this study, and the gas permeation properties were determined using single-component H2, CO2, N2, CH4, n-C4H10, and SF6 at 303–473 K. The membrane showed permeation behavior, wherein the permeance reduced with the molecular size, attributed to the effect of molecular sieving. The separation performances were also determined using the equimolar mixtures of N2–SF6, CO2–N2, and CO2–CH4. As a result, the N2/SF6 and CO2/CH4 selectivities were as high as 710 and 240, respectively. However, the CO2/N2 selectivity was only 25. These results propose that the high-silica CHA-type zeolite membrane is suitable for the separation of CO2 from CH4 by the effect of molecular sieving.

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