Novel Access to Propagation Rate Coefficients of Radical Polymerization by the SP-PLP-EPR Method

A novel method for kp measurement is presented, in which time‐resolved electron paramagnetic resonance detection of radical concentration after applying a single laser pulse (SP−PLP−EPR) is carried out in conjunction with measuring monomer conversion induced by the laser pulse. The method is particularly useful for the study of fully ionized monomers, as will be outlined by experiments on trimethylaminoethyl methacrylate chloride (TMAEMA, 2‐(methacryloyloxy)‐N,N,N‐trimethylethan‐1‐aminium chloride, 20 wt% in aqueous solution) at 60 °C. In addition to kp, the method provides termination rate coefficient data. The reliability of the so‐obtained rate coefficients is demonstrated by chemically induced experiments and by measuring TMAEMA conversion after single‐pulse initiation via near‐infrared (NIR) spectroscopy. Time‐resolved EPR measurement of radical concentration after instantaneous pulsed‐laser‐induced production enables analysis of propagation and termination kinetics for slowly terminating macroradicals. The reliability of the so‐obtained data is checked by additional NIR experiments.