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Bond rupture during ozone cracking of torsional loaded styrene–butadiene
Author(s) -
Devries K. L.,
Moore N. B.,
Williams M. L.
Publication year - 1972
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1972.070160606
Subject(s) - materials science , composite material , cracking , strain rate , natural rubber , ultimate tensile strength , strain energy release rate , strain (injury) , fracture mechanics , electron paramagnetic resonance , nuclear magnetic resonance , physics , medicine
The molecular bond rupture rate during ozone attack of torsionally loaded rubber was determined from electron paramagnetic resonance (EPR) measurements. The rupture rate was successfully correlated by a Griffith‐type energy balance to the strain‐energy release rate in the samples. These observations substantiate the results from a similar study on tensile loading previously reported. In both cases there is a one‐to‐one correspondence between the rate of bond rupture (or crack growth) and the rate of energy release from the strain field and external work. A fracture energy, γ n , of approximately 5×10 −12 (±20%) ergs per free radical formed during the cracking was experimentally determined.