Magnetic silica:epoxy composites with a nano- and micro-scale control

Abstract

This is a postprint version of the following published document:Crespo, M., González, M. y Pozuelo, J. (2014) h i g h l i g h t s g r a p h i c a l a b s t r a c tWe present a strategy that permits the nanoscale and micro scale con trol through a simple protocol. Cu Ni ferrites were prepared into the structure pores if commercial silica with a size control by annealing temperature.Composites with epoxy matrix wereThe reinforcements provided an increase in glass transition temperature and decomposition temperature of the composites.Multiscale composites with magnetic properties were prepared by incorporating Cu Ni nanoferrites filled silica microparticles in an epoxy matrix. The size of the nanoferrites was controlled both by the structure of the silica template and the annealing temperature (700 and 900 C) used during the syn thesis procedure. The ferrite:silica particles prepared at 700 C showed a narrow size distribution close to 8.3 nm with a superparamagnetic behaviour. A less symmetric size distribution was obtained when annealing was performed at 900 C, with diameters ranging from 15 to 80 nm. The reinforcement incorporation increased up to 7 C the glass transition temperature and 30 C the decomposition tem peratures of the composites. The proposed strategy permits the nanoscale control, by the trapping effect of the silica on the magnetic nanoparticles, as well as the control of the micro scale distribution through a simple protocol. These composites could have potential applicability as EMI shielding materials, owing to their magnetic nature, lightweight and enhanced thermal stability.

Electromagnetic Shielding Materials in GHz Range

“…For this reason, magnetic nanoparticles have been incorporated to composites in order to improve the shielding efficiencies. Although some studies have been carried out incorporating only magnetic particles to polymer matrices, the majority of the investigations are focused to verify the extraordinary combination and synergistic effect between carbonaceous constituents and magnetic nanoparticles; Table compiles the most relevant works in these materials.…”

Effect of Pickering emulsion on the mechanical performances and fracture toughness of epoxy composites

“…Thirdly, the introduction of functional monomer modified the compatibility between SiO 2 nanoparticles and the epoxy matrices and improved the dispersity of SiO 2 nanoparticles. Lastly, when the epoxy composites was impacted, SiO 2 nanoparticles would debond from the epoxy matrix, dissipative part of impact energy, and then enhance the toughness of epoxy composites …”

“…Thirdly, the introduction of functional monomer modified the compatibility between SiO 2 nanoparticles and the epoxy matrices and improved the dispersity of SiO 2 nanoparticles. Lastly, when the epoxy composites was impacted, SiO 2 nanoparticles would debond from the epoxy SEM morphologies of tensile fracture surface of the reference sample (A), epoxy composites with 2.7 wt%SiO2 nanoparticles (B), and epoxy composites with 6.7 wt% SiO2nanoparticles (C).matrix, dissipative part of impact energy,58 and then enhance the toughness of epoxy composites. 59 4 | CONCLUSIONS The addition of SiO 2 nanoparticles, which is a kind of nanoparticles, can obviously improve the mechanical properties and toughness of epoxy thermosets and composites.…”

Synthesis of Ni0.5Zn0.5Fe2O4-reinforced E-glass/epoxy nanocomposites for radar-absorbing structures

“…The peak positions comply with JCPDS file no. 8-0234 [38], corresponding to the crystallographic planes of the single-phase cubic spinel structure of Ni 0.5 Zn 0.5 Fe 2 O 4 with no impurity phase [39][40][41]. The presence of sharp peaks indicates high crystallinity.…”