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Polymeric membranes are extensively used for gas separations but their performance is limited by the upper bound trade‐off discovered by Robeson in 1991. Among the attractive modifications available to increase the performance of polymeric membranes, polymer blending is a unique technique because it offers a time‐ and cost‐effective method of tuning the properties of membranes. A variety of polymer blends has been explored in recent years. The application of polymer blends in gas separation membranes is described by critically analyzing the performance of polymer blend membranes. Polymer blend membranes of different polymer pairs are reviewed and evaluated in terms of phase behavior, permeability, and selectivity.

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In the present work, thermophysical properties such as density (F), dynamic viscosity (η), refractive index (n D ), and surface tension (σ) of aqueous piperazine (PZ) solutions with mass fractions (100w ) 1. 74, 5.16, 10.35) have been measured from temperatures (298.15 to 338.15) K. All of these properties have also been measured for the aqueous blends of N-methyldiethanolamine (MDEA) and piperazine (PZ) with mass fractions {100(w 1 /w 2 ) ) 32.28/1. 74, 32.28/5.16, 32.28/10.35, 48.80/1.74, 48.80/5.16, 48.80/10.35)} for the entire temperature range. The limit of PZ solubility in water was measured by the addition of a known quantity of anhydrous PZ (solid crystals) in 20 mL of distilled water at temperatures (278 to 343) K with a regular interval of 5 K. The experimental values of the studied physical properties have been compared with the literature and also correlated as a function of temperature. The coefficients of thermal expansion (R p ) values have been calculated from their experimental density data using an empirical correlation. A thermogravimetric analyzer (TGA) has been used to explore the thermal stability of the studied solvent systems at a heating rate of 10 °C • min -1 .

In this work, physical properties such as dynamic viscosity at (298.15 to 338.15) K, surface tension, and refractive index at temperatures (303.15 to 333.15) K of pure and aqueous N-methyldiethanolamine (MDEA) solutions (with mass fraction of MDEA of 0.3228 and 0.4880) were measured at atmospheric pressure and correlated. A thermogravimetric analyzer (TGA) was used to study the thermal stability of solvents in the presence of nitrogen (20 mL·min−1), at a heating rate of 10 °C·min−1.