Polymer Crystallization: Universal Macroscopic Description via the Autocatalytic Hoffman-Lauritzen Approach

For the description of the crystallization in polymers, the exponential autocatalytic N ^th-order model, paired with the Hoffman-Lauritzen nucleation-growth theory (the conjunction denoted as the MCHL model), was introduced as an alternative to the classical Avrami concept. It was demonstrated, employing theoretical simulations, that the Avrami-based kinetics exhibits a strictly defined interval of asymmetries for the derivative kinetic data (conformable to the differential scanning calorimetry crystallization peaks), often incompatible with the experimental observations. On the other hand, the MCHL model is highly flexible, reproducing and largely extending the range of the Avrami asymmetries, thus effectively covering all possible single-process manifestations of the polymer crystallization mechanisms. The MCHL model was further proven to comply with the t _0.5-based evaluation of the Hoffman-Lauritzen nucleation constant, reducing the number of variables in the nonlinear optimization-based enumeration of the model's parameters. A unique relationship between the Avrami and MCHL kinetic was found.