Title | Network Modulus and Superelasticity |
Publication Type | Journal Article |
Year of Publication | 1994 |
Authors | SP Obukhov, M Rubinstein, and RH Colby |
Journal | Macromolecules |
Pagination | 3191 - 3198 |
Date Published | 01/1994 |
Abstract | We discuss the elastic modulus G and swelling/deswelling behavior of networks as a function of their concentration Ï and their preparation state. Simple scaling ideas reproduce the prediction of James and Guth for the modulus of networks swollen in a θ solvent (G â¼ Ï1/3) but lead to a new prediction in a good solvent (G â¼ Ï7/12). We also suggest that both fully swollen modulus and dry modulus are related to swelling in ways that are independent of the network preparation details. By cross-linking long chains at low concentration and removing the solvent, many temporary entanglements are formed that force each network strand into a double-folded treelike compact configuration. These deswollen networks are capable of stretching by enormous amounts (â¼100X) without breaking (superelastic) and have a much lower modulus than melt-cross-linked networks. The energy stored in temporary entanglements during deswelling is released upon stretching, leading to a weaker-than-linear dependence of stress Ï on elongation λ in tension (Ï â¼ Î»1/3). © 1994 American Chemical Society |
DOI | 10.1021/ma00090a012 |
Short Title | Macromolecules |