Evaluation of Automated Synthesis for Chain and Step-Growth Polymerizations: Can Robots Replace the Chemists?

This article explores current challenges in the use of automated parallel synthesizers in polymeric materials research. Four types of polymerizations were investigated: carbodiimide-mediated polyesterification, diphenol phosgenation, free radical, and reversible addition-fragmentation chain-transfer (RAFT). Synthetic challenges of condensation polymerization, such as liquid and solid dispensing accuracy, dropwise addition, and toxic chemical handling, were successfully met using the automated synthesizer. Both solid and liquid dosing of the diphenol and diacid were successful for polyarylate synthesis. The high precision of liquid dispensing made it possible to achieve stoichiometric balance using reagent stock solutions. For all reactions, molecular weights and their reproducibility were comparable to those obtained with manual synthesis. For RAFT polymerizations, solvent and mol ratio of chain transfer reagent to initiator were successfully optimized on the automated synthesizer and a library of over 60 polymethacrylate copolymer compositions was generated. Considerable savings in time relative to manual methods were achieved when generating polymer libraries (e.g., 4.5x faster for 96 polymethacrylates and 20x faster for 45 for polycarbonates). (c) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 49-58, 2009