Nanocomposite hydrogels: Fracture toughness and energy dissipation mechanisms |
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| Authors: | Andrea Klein Philip G. Whitten Katharina Resch Gerald Pinter |
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| Affiliation: | 1. Materials Science and Testing of Plastics, Department of Polymer Science, Montanuniversit?t Leoben, Leoben, Austria;2. Faculty of Engineering, University of Wollongong, New South Wales, Australia;3. ARC Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, AIIM Facility, Innovation Campus, University of Wollongong, New South Wales, Australia |
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| Abstract: | In this study, fracture toughness of nanocomposite hydrogels is quantified, and active mechanisms for dissipation of energy of nanocomposite hydrogels are ascertained. Poly(N,N‐dimethylacrylamide) nanocomposite hydrogels are prepared by in situ free radical polymerization with the incorporation of Laponite, a hectorite synthetic clay. Transmission electron microscopy proves exfoliation of clay platelets that serve as multifunctional crosslinkers in the created physical network. Extraordinary high fracture energies of up to 6800 J m?2 are determined by the pure shear test approach, which shows that these soft and stretchable hydrogels are insensitive to notches. In contrast to single‐ and double‐network hydrogels, dynamic mechanic analysis and stress relaxation experiments clarify that significant viscoelastic dissipation occurs during deformation of nanocomposite hydrogels. Similar to double‐network hydrogels, crack tip blunting and plastic deformation also contribute to the observed massive fracture energies. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1763–1773 |
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| Keywords: | crosslinking fracture fracture toughness hydrogels inorganic crosslinker inorganic/organic network nanocomposite hydrogels networks |
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