Exploring Physical Properties of Polyvinyl Acetate + Ionic Liquid Composite Membranes for the Separation of HFC-32 and HFC-125

Refrigerants play essential roles in our everyday lives, from providing comfort to food preservation to industrial processes. However, HFC refrigerant mixtures are currently being phased out due to their high global warming potential. Since most refrigerants mixtures are azeotropic, finding a way to separate these mixtures is necessary to repurpose refrigerants in both a cost effective and sustainable fashion. Two possible methods for the separation of refrigerant mixtures are through membranes and ionic liquids. This poster will give an overview on several physical properties of ionic liquid and polyvinyl acetate composite membranes, which aim to combine the separation abilities of both materials in a single membrane. The membranes were created by mixing three ionic liquids, 1-hexyl-3-methylimidazolium ([C₆C₁im][Cl]), 1-hexyl-3-methylimidazolium, bis(trifluoromethylsulfonyl)imide ([C₆C₁im][Tf₂N]), and 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate ([C₆C₁im][FAP]) with polyvinyl acetate in four different weight precents. The densities of each membrane were found using a densitometer, and the membranes were evaluated using a High-Pressure View Cell to find their melting and deterioration points at a certain pressure. Fourier-transform infrared spectroscopy was also used to find the percent transmittance. Results from this study indicate that trends occurring with percent transmittance and density in a specific combination of ionic liquid and polyvinyl acetate may be able to reveal more about the intermolecular interactions between the ionic liquids and polyvinyl acetate.