Flow-Induced Crystallization of Polymers during Multi-Axial Deformation*

Flow- or stretch-induced crystallization (FIC/SIC) is believed to be mainly responsible for the excellent mechanical properties of polymers during real processing. The development of synchrotron radiation (SR) X-ray scattering techniques with high time resolution has been a mainstream research tool to study the structural evolution of polymers under complex external fields. The FIC behaviors of polymers during multi-axial deformation like biaxial stretching, film blowing and service of sounding balloon has been systematically studied with the combination of in-situ SR X-ray scattering and the custom-built devices. Considering the phenomenon of frustrating SIC for natural rubber during biaxial stretching, we proposed a new model for SIC based on the results of theoretical calculation and the in-situ X-ray scattering, which decoupled the free energy contributions of chain orientation from that of conformational entropy reduction. This model is also suitable for the crystallization of polymers under other flow fields.


References
[1] Chemical reviews, 2018, 118(4): 1840-1886.
[2] Macromolecules, 2016, 49(5): 1505-1517.
[3] Macromolecules, 2019, 52(10): 3575-3591.