Tensile and compressive mechanical properties of the hydrogels, including the as-prepared ones (PAM, LmM, BnM) (the conventional chemically crosslinked hydrogels using N,N,N′,N′-methylenebis(acrylamide) as the crosslinker, where n represents 3 × BIS/water [g L−1]) and the swollen one with 90 wt% water content (L2M-S).
Sample | Yield strength [kPa] | Fracture strength [kPa] | Elongation at break [%] | Toughnessa [MJ m−3] | Compressive strengthb [MPa] | Compressive modulusb [MPa] |
---|---|---|---|---|---|---|
L1M | 39.5 | 29.3 | 2355 | 0.69 0.5 | 4.5 | |
L2M | 58.4 | 43.2 | 4068 | 1.99 | 0.9 | 12.9 |
L3M | 62.3 | 45.8 | 4361 | 2.55 | 1.2 | 16.6 |
L2M-Sc | No | >34.0 | >6236 | >1.95 | ||
B1M | — | 41.4 | 318 | 0.10 | — | — |
B2M | — | 59.3 | 204 | 0.08 | — | — |
PAM | 21.7 | 7.0 | 154 | 0.02 | — | — |
Toughness was calculated from the areas under the tensile stress–strain curves.
The hydrogels B1M, B2M, and PAM were too brittle to compress.
The swollen hydrogel L2M-S did not break during the tensile test, accompanied by the disappearance of the yielding phenomenon.