2017-Polym Chem: Energy Dissipation and Mullins Effect of Tough Polymer/Graphene Oxide Hybrid Nanocomposite Hydrogels
writer：Ziqing Tang#, Feng Chen#, Qiang Chen* and Jie Zheng*, and et al.
keywords：Nanocomposite Hydrogels; Graphene Oxide; Mullins Effect; Self-recovery; Mechanical Properties.
source：期刊
specific source：Polymer Chemistry
Issue time：2017年
Nanocomposite
hydrogels (NC gels) are considered as one of high strength hydrogels. Graphene
oxide (GO), thanks to its amphiphilic, mechanical, optical property, is widely
used as fillers to incorporate into different hosting materials (elastomers, plastics,
and hydrogels) to improve their mechanical properties. In this work, we used in
situ free radical polymerization to synthesize polyacrylamide (PAAm)/GO
hybrid NC gels in the presence of GO nanosheets and a very small amount of
chemical crosslinkers (N, N''''-methylenebisacryamide, MBA<0.1
mol%). By optimizing GO and MBA concentrations, the resulting PAAm/GO gels can
achieve elastic modulus of 66 kPa, fracture stress of 0.27 MPa, fracture strain
of 13.76 mm/mm, deformed energy of 2.52 MJ/m3, and tearing energy of
964 J/m2. Due to the presence of physical interactions between PAAm
and GO nanosheets, PAAm/GO gels demonstrate λ-dependent
energy dissipation and Mullins self-recovery behaviors. The gels can rapidly
recover their stiffness and toughness by 76% and 60%, respectively after 30
min. resting at room temperature. The possible toughening mechanisms and
Mullins effect of PAAm/GO gels were proposed and compared with those of filler
rubbers and other high strength hydrogels. This work provides new viewpoints to
develop tough hydrogels by introduction of GO into other hydrogels with a good mechanical
balance between strong chemical bonding and reversible physical bonding.