Quantitative Structure–Property Relationship Model for Predicting the Propagation Rate Coefficient in Free-Radical Polymerization

In this work, a generalized quantitative structure–property relationship (QSPR) model is developed for predicting k p by using norm index (NI)-based descriptors, which is the so-called k p (T, NI)-QSPR model. The as-developed model enables the use of one unified formula to calculate k p values for a wide range of monomers, including linear and branched (meth)­acrylates, nitrogen-containing methacrylates, hydroxyl-containing (meth)­acrylates, and so forth. Importantly, the model exhibits excellent performance when compared with the benchmark k p values from the literature, and model validation proves the reasonable goodness-of-fit, robustness, predictivity, and reliability of the as-developed model. Meanwhile, the Arrhenius parameters show a clear kinetic behavior, indicating that acrylates have smaller fit, robustness, predictivity, and reliability of the as-developed model. Meanwhile, the Arrhenius parameters show a clear kinetic behavior, indicating that acrylates have smaller E a values than methacrylates, which render higher k p values and activities in free-radical polymerization for acrylates. Notably, the model allows the prediction of k p values of monomer mixtures and new monomers. In view of the satisfactory accuracy in determining k p values, it is expected that our proposed method will contribute to the determination of kinetic parameters beyond propagation kinetics for a wide monomer range, and the obtained Arrhenius parameters can further improve the fundamental understanding of radical polymerization kinetics.