Abstract
We focus on the role of dynamical heterogeneities on the weak mechanical nonlinearities of amorphous polymers near and above the glass transition temperature Tg by combining experiments and numerical coarse-grained simulations. The acceleration of the macroscopic nonlinear modulus relaxation resulting from the applied stress is measured below yielding. As a result of dynamic disorder, the macroscopic acceleration differs from the local acceleration. We obtain a good agreement of experimental measurements with simulations computed by using an exponential function of the square stress for the local acceleration. Further, the length scale of dynamical heterogeneities is deduced.
4 More- Received 19 June 2020
- Accepted 16 February 2021
DOI:https://doi.org/10.1103/PhysRevMaterials.5.033601
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