Kinetic Analysis of Conjugated Polymer Degradation in a Flow Reactor

ABSTRACT Flow synthesis is emerging as a powerful method for the rapid and reproducible synthesis of conjugated polymers. However, chain scission is a potential side reaction that can limit the maximum obtainable molecular weight. In this report, the kinetics of conjugated polymer degradation in flow were studied using methods based on molecular weight models and monitoring the refractive index at the incipient portions of size‐exclusion chromatography peaks. After evaluating the suitability of these methods, they were used to calculate degradation rate constants. In addition to observing that degradation rates increased with increasing molecular weight, by studying the conjugated polymers PTB7 and PTB7‐Th, we found that degradation rates were also influenced by the size of the side chain on the conjugated polymer. These results provide new support for the mechanochemical nature of degradation and are expected to aid in the development of new flow syntheses for conjugated polymers.