Effect of Nematic Ordering on the Elasticity and Yielding in Disordered Polymeric Solids
A Giuntoli and N Calonaci and S Bernini and D Leporini, JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 55, 1760-1769 (2017).
The relation between elasticity and yielding is investigated in a model polymer solid by Molecular-Dynamics simulations. By changing the bending stiffness of the chain and the bond length, semicrystalline and disordered glassy polymers - both with bond disorder - as well as nematic glassy polymers with bond ordering are obtained. It is found that in systems with bond disorder the ratio tau gamma/G between the shear yield strength tau gamma and the shear modulus G is close to the universal value of the atomic metallic glasses. The increase of the local nematic order in glasses leads to the increase of the shear modulus and the decrease of the shear yield strength, as observed in experiments on nematic thermosets. A tentative explanation of the subsequent reduction of the ratio tau gamma/G in terms of the distributions of the per-monomer stress is offered. (C) 2017 Wiley Periodicals, Inc.
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