Separation of volatile compounds from polymers by physisorption

After synthesis, specialty polymers can be difficult to purify from residual volatile monomers and solvents in a precise and reproducible manner using current standard separation techniques, which also generate large amounts of waste. Herein, we report a proof-of-principle study of a cost-effective and versatile method for separating residual volatile compounds from synthetic polymers via physisorption (i.e., polymer purification by physisorption (3P)). Model polymers were used to evaluate the capabilities and advantages of the 3P method over standard purification techniques regarding separation of volatile compounds, process solvent to polymer yield, and final properties of the resulting polymers. Compared to dialysis and precipitation, the 3P method could separate up to 99% of the residual monomer from a polymerization reaction using a significantly lower fraction of solvent. Unlike the benchmark methods, the molar mass and dispersity of polymers purified by the 3P process remain practically unaffected; polymers were quantitatively recovered for subsequent applications (e.g., precursors for block copolymer synthesis or characterization purposes). The 3P method represents a straightforward technique for polymer purification and is suitable for automation, which will help to overcome the unsolved and labor-intensive task of purifying (co)polymer libraries derived from high-throughput experimentation.