Self-Healing Magnetorheological Elastomer for Vibration Damping

In this work, magnetorheological elastomers (MRE) based on nickel zinc ferrite and natural rubber were prepared. Self-healing capability was employed to the MRE by peroxide induced graft polymerization between zinc thiolate and natural rubber to produce reversible ionic crosslinks that can recover the properties of the fracture materials. Evidence that reversible ionic crosslinks occurred was determined by tensile test of original and healed sample. The results revealed that the tensile strength of the MRE recovered 56% in a minute and almost 100% in 10 minutes at room temperature. The morphology of the fractured surface also showed the fracture area was recovered after the healing processed. The dynamic mechanical analysis of the MREs under cyclic loading were also examined with parallel plate rheometer.

Bis{μ-2,2′-[(butane-2,3-diylidene)bis(azanylylidene)]dibenzenethiolato}dizinc(II)–dimethyl sulfoxide–methanol (2/0.18/0.82)

The asymmetric unit in the crystal structure of the title compound, [Zn2(C16H14N2S2)2]2·0.18C2H6OS·0.82CH3OH, consists of two ordered bis{μ-2,2′-[(butane-2,3-diylidene)bis(azanylylidene)]dibenzenethiolato}dizinc(II) molecules and a disordered solvent combination at the same location which refined to 18.1 (7)% dimethyl sulfoxide and 81.9 (7)% methanol. The compound has a metallic cluster structure formed by the joining together of two zinc(II) complex molecules, forming a rhomboidal Zn2S2arrangement. This complex was previously suggested on the basis of nonstructural evidence to be a monomer [Jadamus, Fernando & Freiser (1964).J. Am. Chem. Soc.86, 3056–3059]. Each ZnIIatom is five-coordinated and exhibits distorted trigonal bipyramidal geometry. The structure may be of interest with respect to zinc–thiolate bonds, the coordination chemistry of Schiff bases and the folding of proteins. The structure displays weak intermolecular C—H...S, C—H...O and C—H...N interactions, and contains a unique bonding arrangement of the ligands around the Zn2S2rhomboid.