(401f) Impact of Diluents on the Poly(acrylonitrile-butadiene-styrene) Membrane Synthesis

Poly(acrylonitrile-butadiene-styrene) (ABS) is a common polymer used in toys and automobile parts due to its high impact strength. ABS is also used in membrane fabrication for water and air filtration applications. However, ABS membrane often employs toxic solvents during fabrication and often produces dense low porosity membranes. To increase sustainability and safety during membrane synthesis, green solvents can be employed. Green solvents such as PolarClean often have a higher viscosity than traditional solvents which could also lead to the formation of dense membrane architectures. This work investigated the synthesis of ABS membranes using PolarClean and the influence of diluents on the phase inversion process. The addition of water-soluble diluents, ethanol, and acetone was hypothesized to lower solution viscosity allowing for the formation of more porous structure. Additionally, the solvents were hypothesized to increase solution volatility which would enable membranes with higher rejection against a model contaminant. Membranes were fabricated with different solvent compositions (0,10,20% diluent) and evaporation times (0,1minute). The resulting membranes were characterized using scanning electron microscopy (SEM) to visualize the pore structure and a pycnometer was used to determine the porosity. Membrane performance, including water flux and bovine serum albumin rejection, was evaluated using normal flow filtration. The resulting membranes had a finger-like morphology attributed to the high solubility of PolarClean in water. The ethanol containing solutions were found to undergo a liquid-liquid separation when in contact with water. Evaporation time significantly impacted the resulting membrane architecture due to a prolonged phase inversion process triggered by humidity. In all cases, evaporation time was able to enhance rejection of bovine serum albumin. Overall, the study found that PolarClean can be an effective solvent to create ABS membranes. In addition, we found that ethanol diluent can alter the phase separation behavior vs acetone by triggering a liquid-liquid phase separation.