High MOF loading in mixed-matrix membranes utilizing styrene/butadiene copolymers

Abstract

A series of styrene/butadiene polymers were combined with up to 90 wt% UiO-66 to form mixed-matrix membranes with varying physical properties. Notably, polystyrene-block-polybutadiene (SBS) membranes retained much of the processability and flexibility of the native polymer component and the porosity, chemical tunability, and adsorption of the native MOF.

Understanding the origins of metal–organic framework/polymer compatibility

“…All solvents, starting materials, and polymers were purchased from chemical suppliers and used without further purification (Sigma Aldrich, Arkema, Alfa Aesar, EMD, and TCI). UiO-66(Zr) 22 was synthesized according to previously-reported methods, 23 yielding 200 nm truncated octahedral particles (Fig. S17 † ) with the expected powder X-ray diffraction pattern (Fig.…”

“…MOF-based MMMs with PEG ( M z = 900 000 g mol –1 , PDI = 1.2, purchased from Sigma Aldrich) were fabricated according to a modified method. 21 , 23 The MOF component was dispersed in acetone (3.5 wt% MOF) via ultrasonication for 30 min. The polymer component was dissolved separately in water (3.5 wt%) to a honey-like viscosity.…”

“…The behavior of this composite is further compared with that predicted for three different UiO-66-based MMMs: using PIM-1, polystyrene (PS), and polyethylene glycol (PEG) as the polymer component. Composites including UiO-66 nanoparticles in PS, 23 and in PIM-1 24 , 25 have already been reported. PEG-based solid electrolytes incorporating MOFs are known, 26 – 29 but they all incorporate lower loadings (<40%) of MOF and their membrane-forming characteristics are rarely discussed in detail.…”

Mixed‐Matrix Membranes

“…The UTS decreased in line with increasing MOF loading, but the elastic modulus initially increased over the neat polymer at low loadings . Even better results were achieved with MMMs based on styrene/butadiene copolymers and high MOF loadings . As an interesting aside, alternative approaches to MOF‐MMM fabrication should be more widely explored to improve the mechanical strength (and other properties).…”

Mixed‐Matrix‐Membranen

“…Die Reißfestigkeit nahm in Übereinstimmung mit der zunehmenden MOF‐Beladung ab, der Elastizitätsmodul jedoch stieg vom reinen Polymer bei niedrigerer Beladung zunächst an . Mit MMMs aus Styrol/Butadien‐Copolymeren und hohen MOF‐Beladungen wurden sogar noch bessere Ergebnisse erreicht . Als interessante Nebenbemerkung sei erwähnt, dass alternative Herangehensweisen zur MOF‐MMM‐Fertigung weitgehender untersucht werden sollten, um die mechanische Festigkeit (und andere Eigenschaften) zu verbessern.…”