Quantifying synergistic initiator interactions in high‐pressure polymerization through reaction‐network analysis

Abstract In high‐pressure free‐radical polymerization, peroxide initiators are routinely blended to improve process performance, yet their synergistic interactions remain insufficiently elucidated. Here, these effects are probed using reaction‐network analysis. Reaction networks of blended initiators were generated with reaction mechanism generator (RMG) and refined through experiments. Network analysis revealed diverse interaction patterns, motivating three complementary metrics to quantify synergy: rate enhancement ( k ‐fold increase), radical generation capacity (GI), and radical persistence. The combined behavior of these metrics distinguishes cooperative synergy from largely independent decomposition. Synergistic enhancement requires meaningful decomposition overlap and the formation of a complementary, stable radical pool. Incorporating the extracted parameters and GI‐corrected radical release into a reactor model enabled formulation optimization. Application to an industrial tubular reactor reduced initiator consumption by over 30% while maintaining conversion and molecular‐weight targets. These findings offer mechanistic insight and practical guidance for initiator design in industrial high‐pressure polymerization.