Deforming glassy polystyrene: influence of pressure, thermal history, and deformation mode on yielding and hardening

Vorselaars, Bart and Lyulin, Alexey V. and Michels, M. A. J. (2009) Deforming glassy polystyrene: influence of pressure, thermal history, and deformation mode on yielding and hardening. The Journal of Chemical Physics, 130 (7). 074905. ISSN 0021-9606

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Item Type:Article
Item Status:Live Archive

Abstract

The toughness of a polymer glass is determined by the interplay of yielding, strain softening, and strain hardening. Molecular-dynamics simulations of a typical polymer glass, atactic polystyrene, under the influence of active deformation have been carried out to enlighten these processes. It is observed that the dominant interaction for the yield peak is of interchain nature and for the strain hardening of intrachain nature. A connection is made with the microscopic cage-to-cage motion. It is found that the deformation does not lead to complete erasure of the thermal history but that differences persist at large length scales. Also we find that the strain-hardening modulus increases with increasing external pressure. This new observation cannot be explained by current theories such as the one based on the entanglement picture and the inclusion of this effect will lead to an improvement in constitutive modeling.

Keywords:polymers, Polystyrenes, yield stress, strain hardening, Annealing, Molecular dynamics, Macromolecules
Subjects:F Physical Sciences > F320 Chemical Physics
F Physical Sciences > F162 Polymer Chemistry
F Physical Sciences > F311 Engineering Physics
F Physical Sciences > F310 Applied Physics
H Engineering > H140 Mechanics
Divisions:College of Science > School of Mathematics and Physics
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ID Code:18231
Deposited On:05 Aug 2015 15:34

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