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Hydroxyl terminated polybutadiene based polyurethanes with various crosslinker compounds have been prepared to investigate the effect of crosslinker content and structure on polyurethanes mechanical properties. Three various crosslinkers have been used in this study, including trimethylolpropane, triethanolamine, and boron trifluoride triethanolamine complex. The results established that increasing crosslinker content increased the polyurethane strength. Moreover, boron trifluoride triethanolamine complex showed better ability in making network polyurethanes. The tensile test revealed that using boron trifluoride triethanolamine complex as crosslinker led to increasing chemical crosslinking bonds in comparison to two other crosslinkers via catalyzing side reaction like chain coupling. Swelling test and dynamical‐mechanical analysis confirmed this result, too.

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Highlighting mixed matrix membrane (MMM) susceptibility in improving the membrane performance along with established p-tert-butylcalix[4]arene (CA) ability in CO 2 sorption, Pebax-1657-based MMMs have been prepared using various contents of CA. In this regard, well-distributed particles in the polymeric matrix without agglomeration has been achieved because of the organic nature of both Pebax-1657 and CA. Additionally, their miscibility was intensified by noncovalent interactions between functional groups on the backbone of two materials. Furthermore, permeability of CO 2 gas was significantly increased by introducing CA into the polymeric matrix, as well as selectivity of CO 2 /N 2 and CO 2 / CH 4 . This result was more remarkable in the sample containing 0.75 wt % CA that improved the permeation of CO 2 from 140.78 Barrer to 265.18 (about 88%) in comparison to the pure Pebax-1657 membrane. Accordingly, the selectivity of CO 2 /CH 4 and CO 2 /N 2 was enhanced from 25.35 to 51.51 (almost 103%) and from 43.18 to 109.16 (almost 152%), respectively, compared with the pure membrane. As a consequence, physical interactions between functional groups of CA and CO 2 gas were considered to be the key parameter affecting the remarkable permeation results. It is noteworthy that the MMM containing 0.75 wt % of CA overpassed the 2008 Robeson upper-bound limit.