Strain-induced crystallization mechanical performance

Strain are of less interest in accounting for the failure properties of rubber. However, the minimum strain required for crystallization determines the stress concentration necessary to induce crystallization in the vicinity of a crack, as well as its spatial extent. Thus, this minimum strain plays a governing role in mechanical performance. Among the various grades of NR, the greater the purity, the higher the strain required to induce crystallization (Choi and Roland, 1997). 

Usually, creep deformation of ice single crystals is associated to a steady-state creep regime, with a stress exponent equal to 2 when basal glide is activated . In the torsion experiments performed, the steady-state creep was not reached, but one would expect it to be achieved for larger strain when the immobilisation of the basal dislocations in the pile-ups is balanced by the dislocation multiplication induced by the double cross-slip mechanism. 

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