Viscoplasticity and large-scale chain relaxation in glassy-polymeric strain hardening
Abstract
A simple theory for glassy-polymeric mechanical response that accounts for large-scale chain relaxation is presented. It captures the crossover from perfect-plastic response to Gaussian strain hardening as the degree of polymerization N increases, without invoking entanglements. By relating hardening to interactions on the scale of monomers and chain segments, we correctly predict its magnitude. Strain-activated relaxation arising from the need to maintain constant chain contour length reduces the characteristic relaxation time by a factor ∼γ˙N during active deformation at strain rate γ˙ . This prediction is consistent with results from recent experiments and simulations, and we suggest how it may be further tested experimentally.
- Publication:
-
Physical Review E
- Pub Date:
- October 2010
- DOI:
- 10.1103/PhysRevE.82.041803
- arXiv:
- arXiv:1004.0410
- Bibcode:
- 2010PhRvE..82d1803H
- Keywords:
-
- 61.41.+e;
- 62.20.F-;
- 81.40.Lm;
- 83.10.Rs;
- Polymers elastomers and plastics;
- Deformation and plasticity;
- Deformation plasticity and creep;
- Computer simulation of molecular and particle dynamics;
- Condensed Matter - Soft Condensed Matter
- E-Print:
- The theoretical treatment of the mechanical response has been significantly revised, and the arguments for coherent relaxation during active deformation made more transparent