Polypyrrolones for membrane gas separations. I. Structural comparison of gas transport and sorption properties

Features of the Gas-Permeable Crystalline Phase of Poly-2,6-dimethylphenylene Oxide

“…This can occur due to the low heat of sorption of hydrogen and helium and is usually found in highly permeable polymers [ 32 ], for example, polyacetylenes [ 33 ]. Similar “anomalies” have also been noted for polymers belonging to the class of organic molecular sieves, for example, moderately permeable polypyrrolones [ 34 ], as well as highly permeable polymers with intrinsic microporosity (PIM-1 [ 35 ] or PIM-TMN-Trip [ 36 ]). For such polymers, this may be due to the ordering of chain packing in the amorphous phase [ 37 ] and the so–called “entropic selectivity” typical for such polymers and carbon molecular sieves [ 38 , 39 , 40 , 41 ].…”

“…It is noteworthy that for an amorphous PPO-2/50 °C sample and for PPO-1 sample, the values of E D for oxygen and CO 2 are almost the same, and for PPO-2 and PPO-4 samples, the value of E D for CO 2 is less than that for oxygen. This kind of pattern is again typical for organic molecular sieves class of polymers, for example, polypyrrolones [ 34 ] and polymers of intrinsic microporosity [ 35 , 36 , 42 , 43 ], and for some highly permeable polyacetylenes [ 32 , 33 ].…”

Poly(dimethylsiloxane-urethane) membranes: Effect of hard segment in urethane on gas transport properties

“…Systematic variations of the monomer chemical structure have been used to achieve simultaneous increase in permeability and permselectivity values. The increase in the permselectivity with a little loss of permeability is achieved by chemical structure changes that reduce the rotational mobility around the flexible linkage in the polymer main chain without significantly affecting intersegmental packing [8][9][10].…”

Effect of Temperature and Mechanical Stress on Barrier Properties of Polymeric Films Used for Food Packaging

“…The permselectivity, as reported by Zimmerman and Koros [23], increases because the matrix has a great ability to selectively distinguish between molecules of similar size: kinetic diameters for O 2 and CO 2 are 3.46 Â 10 À8 cm and 3.30 Â 10 À8 cm, respectively [24]. Only PE film showed no influence of mechanical stress on O 2 /CO 2 selectivity changes (Figure 6).…”