Fracture behavior of elastomers: a new look into phenomenology known for over six decades*

For plastics we have advanced a scaling level molecular description of yielding and brittle-ductile transition.^{1, 2}  In contrast polymer physics has not really gone beyond the classical formulation of rubber elasticity for crosslinked polymers because of the lack of structural characterization of the network.  A long-standing question is why elastomers seem to have rather “low” tensile strength.  On the other hand, the same elastomers are known³ to show improved tensile strength under higher rate of drawing.  Separately, toughness (i.e., critical energy release rate) is found to grow sharply with the rate, which has been interpreted as due to increased energy dissipation.⁴  We apply time-dependent, spatially resolved polarized optical microscopy to further investigate the phenomena.

1.   A phenomenological molecular model for yielding and brittle-ductile transition of polymer glasses. J. Chem. Phys. 2014, 141, (9), 094905.

2.   Crazing and yielding in glassy polymers of high molecular weight. Polymer 2020, 197, 122445.

3.   Smith, T. L. Ultimate tensile properties of elastomers. I. Characterization by a time and temperature independent failure envelope. Journal of Polymer Science Part A: General Papers 1963, 1, (12), 3597-3615.

4.   Gent, A. Adhesion and strength of viscoelastic solids. Is there a relationship between adhesion and bulk properties? Langmuir 1996, 12, (19), 4492-4496