Flow‐Induced Crystallization of Semicrystalline Polymer

Abstract

AbstractThis article summarizes our recent efforts to understand the fundamental mechanism of flow‐induced crystallization of semicrystalline polymers in the melt state. Three general experimental phenomena for polymer crystallization underflow are presented first, which are related to crystal morphology, polymorphism, and crystallization kinetics. Then, theoretical efforts to clarify the above phenomena are briefly summarized. The validation of coil‐stretch transition proposed by de Gennes and the stretched network model in flow‐induced crystallization of polymers is discussed. We proposed a new thermodynamics scenario to quantify the nucleation barrier through decoupling the contribution of conformational entropy and segmental orientation order of initial deformed melt. We also incorporated the crystal morphology and polymorphism into calculating the free energy of nuclei. The proposed model can well agree with the experimental observations. Finally, we present some recent synchrotron radiation X‐ray scattering and molecular dynamics simulation results, which challenge the classical one‐step nucleation model. These results suggest a multistep ordering of flow‐induced nucleation, which is discussed in detail.