| Abstract: | Results of uniaxial tension and compression experiments are reported on crosslinked polydimethylsiloxane (PDMS) networks in the unswollen state over the range 0.5 < α?1 < 1.2 where α is the extension ratio. Curves representing the reduced force f] = f(V0/V)1/3(α – α?2)?1 plotted against α?1 can be approximated by straight lines for 0.5 < α?1 < 0.9, in agreement with the phenomenological Mooney equation. As α?1 approaches 1, however, they tend to level off and continue into the α?1 > 1 region with decreasing slope. These results are in agreement with the predictions of recent elasticity theories that incorporate the effect of junction-chain entanglements in the elastic free energy. |
