No abstract

Silicone rubber composites have attracted wide attention due to their excellent thermal stability and climate resistance. However, it is still a challenge to synthesize these composites with high tensile property without external stimulation. Meanwhile, incorporation of superparamagnetic iron oxide nanoparticles to fabricate magnetic nanocomposites have a broad application prospect. In the present work, aiming to improve the mechanical and magnetic properties of the silicone rubber composite, fumed silica and different content of oleic acid‐modified Fe3O4 nanoparticles are well dispersed in the silicone rubber matrix. The synthesized nanocomposites exhibit excellent thermal stability, superelasticity, superparamagnetic property, and sensitive magnetic response. In particular, a high elongation at break of 1931%, a low storage modulus of 0.56 MPa and a deflection of 27 mm under an applied magnetic field of 1.31 Oe are obtained in the silicone rubber nanocomposite. The present work provides a feasible way to prepare silicone rubber matrix nanocomposites with excellent mechanical and magnetic performance.

The degradation of 4-bromochlorobenzene (4-BCB) containing both chlorine and bromine by mechanochemical destruction (MCD) using CaO powder was investigated. The degradation efficiency of 4-BCB almost achieved 100% after 2 h milling. The debromination rate (0.41 h -1 ) was higher than the dechlorination rate (0.31 h −1 ) which can be ascribed to the lower dissociation energy of C-Br bond than that of C-Cl bond in 4-BCB. The kinetic analysis demonstrates that nucleation growth was the control step of dehalogenation reactions. Additionally, the dehalogenation efficiency increased with increasing rotate speed and milling ball weight. The XRD and FT-IR spectra analysis manifests that the CaO powder was transformed to CaCl2, CaBr2, Ca(OH)2, and CaCO3. The identification of intermediates and analysis of Raman spectra indicates that the 4-BCB degradation by MCD treatment using CaO powder may occur through three pathways: (a) breakup of the benzene ring to form small molecular halogenated hydrocarbons and mineralization to form CO2 and H2O in sequence, (b) dehalogenation reaction to form benzene and monohalogenobenzene and addition reaction of halogen radicals to form dihalogenobenzenes in sequence; (c) polymerization reaction to form biphenyl, halogenated biphenyl, and graphite.

No abstract