Low Conversion 4‐Acetoxystyrene Free‐Radical Polymerization Kinetics Determined by Pulsed‐Laser and Thermal Polymerization

Summary: The free‐radical polymerization kinetics of 4‐acetoxystyrene (4‐AcOS) is studied over a wide temperature range. Pulsed‐laser polymerization, in combination with dual detector size‐exclusion chromatography, is used to measure k p , the propagation rate coefficient, between 20 and 110 °C. Values are roughly 50% higher than those of styrene, while the activation energy of 28.7 kJ · mol −1 is lower than that of styrene by 3–4 kJ · mol −1 . With known k p , conversion and molecular weight data from 4‐AcOS thermal polymerizations conducted at 100, 140, and 170 °C are used to estimate termination and thermal initiation kinetics. The behavior is similar to that previously observed for styrene, with an activation energy of 90.4 kJ · mol −1 estimated for the third‐order thermal initiation mechanism.Joint confidence (95%) ellipsoids for the frequency factor A and the activation energy E a from non‐linear fitting of k p data for 4‐AcOS (black) and styrene (grey).