Microscopic origin of plastic deformation in semicrystalline polymers

The mechanical properties of polymeric materials strongly depend on their morphology and spatial arrangements. We examine the microscopic origin of the non-linear tensile response in amorphous and semicrystalline polymers by performing large-scale molecular dynamics simulations of various chain lengths [1,2]. Computing ratio of microscopic stretch of the polymers relative to the macroscopic stretch, we find that the semicrystalline polymers deform less affinely than their amorphous counterparts. Investigating the microscopic rearrangements of the polymers during tensile deformation, we show that the intercrystalline chain connections known as tie chains contribute significantly to the plastic response in the strain-hardening regime [2]. Our results suggest that the mechanical behavior of semicrystalline polymers is controlled by two interpenetrated networks of entanglements and tie chains.

[1] S. Jabbari-Farouji, J. Rottler, M. Perez, O. Lame, A. Makke & J.-L. Barrat, ACS Macro Lett. 4, 147 (2015).
[2] S. Jabbari-Farouji, O. Lame, J. Rottler, M. Perez & J.-L. Barrat,Physical Review Letters 118 (21), 217802 (2017).