17 research outputs found
Intrinsically Stretchable Supercapacitors Composed of Polypyrrole Electrodes and Highly Stretchable Gel Electrolyte
Novel Cross-Linking Concept of Polymer Network: Synthesis, Structure, and Properties of Slide-Ring Gels with Freely Movable Junctions
Tear Velocity Dependence of High-Strength Double Network Gels in Comparison with Fast and Slow Relaxation Modes Observed by Scanning Microscopic Light Scattering
Swelling behaviors, tensile properties and thermodynamic interactions in APS/HEMA copolymeric hydrogels
Tailored covalently cross-linked hydrogels based on oxidized cellulose sulfate and carboxymethyl chitosan by targeted adjustment of the storage modulus
Toughness Enhancement and Stick–Slip Tearing of Double-Network Hydrogels in Poly(ethylene glycol) Solution
Interactions affecting the mechanical properties of macromolecular microsphere composite hydrogels
Macromolecular microsphere composite (MMC) hydrogel is a kind of tough hydrogel fabricated by using peroxidized macromolecular microspheres as polyfunctional initiating and cross-linking centers (PFICC). The contribution of chemical cross-linking (covalent bonding) and physical cross-linking (chain entanglement and hydrogen bonding) to the mechanical properties are understood by testing the hydrogels, which were swollen in water or aqueous urea solutions to different water contents. The as-prepared MMC gels exhibited moderate moduli (60-270 kPa), high fracture tensile stresses (up to 0.54 MPa), high extensibilities (up to 2500%), and high fracture energies (270-770 J m -2). The moduli of the swollen gels decrease dramatically, but there are no significant changes in fracture tensile strength and fracture strain, even slight increases. More interestingly, the swollen gels show much-enhanced fracture energies, higher than 2000 J m-2. A gradual decrease in the hysteresis ratio and residual strain is also found in the cyclic tensile testing of the hydrogels that were swollen to different water contents. The covalent bonding determines the tensile strength and fracture energy of the MMC gels, whereas the physical entanglement and hydrogen bonding among the polymer chains contributes mainly to the modulus of the MMC gels, and they are also the main reason for the presence of hysteresis in the loading-unloading cycles