Decoration of Fe₃O₄ nanoparticles on the surface of poly(acrylic acid) functionalized multi‐walled carbon nanotubes by covalent bonding

Abstract

Fe 3 O 4 nanoparticles were indirectly implanted onto functionalized multi-walled carbon nanotubes (MWCNTs) leading to a nanocomposite with stronger magnetic performance. Poly(acrylic acid) (PAA) oligomer was first reacted with hydroxyl-functionalized MWCNTs (MWCNTs-OH) forming PAAgrafted MWCNTs (PAA-g-MWCNTs). Subsequently, Fe 3 O 4 nanoparticles were attached onto the surface of PAA-g-MWCNTs through an amidation reaction between the amino groups on the surface of Fe 3 O 4 nanoparticles and the carboxyl groups of PAA. Fourier transform infrared spectra confirmed that the Fe 3 O 4 nanoparticles and PAA-g-MWCNTs were indeed chemically linked. The morphology of the nanocomposites was characterized using transmission electron microscope (TEM). The surface and bulk structure of the nanocomposites were examined using X-ray diffraction, X-ray photoelectron spectrometer (XPS), and thermogravimetric analysis (TGA). The magnetic performance was characterized by vibrating sample magnetometer (VSM) and the magnetic saturation value of the magnetic nanocomposites was 47 emu g À1 . The resulting products could be separated from deionized water under an external magnetic field within about 15 s. Finally, the magnetorheological (MR) performances of the synthesized magnetic nanocomposites and pure Fe 3 O 4 nanoparticles were examined using a rotational rheometer. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4697][4698][4699][4700][4701][4702][4703] 2010

Core-shell Structured Polypyrrole-coated Magnetic Carbonyl Iron Microparticles and their Magnetorheology

“…The saturation magnetization of core-shell particles is lower in comparison with uncoated CI variant, which predicates about magnetic properties reduction of particles by PPy coating. Although it is necessary to use particles with as high saturation magnetization as possible for the remarkable MR effect, the values obtained for CI/PPy particles are still sufficient [14]. Moreover, for the practical use of MR suspensions it is also important to ensure their sedimentation stability.…”

Preparation of polyaniline grafted multiwalled carbon nanotubes and conductive application in polyetherimide

“…4a, the pattern of pristine MWNTs had two diffraction peaks appeared at 25.9 o (plane 002) and 42.8 o (plane 110) respectively, which were developed from the graphite-like structure inside the MWNTs. [25] Characteristic peak of PANI at around 15.1, 20.3, 25.1 o corresponding to (0 1 1), (0 2 0), and (2 0 0) crystal planes of PANI in its emeraldine salt form was observed in Fig. 4c.…”

Physical characteristics of magnetorheological suspensions and their applications

“…The microparticles used are based mainly on Fe-Co, Fe-Ni, FeCrP [57] and CI, in addition to iron oxides [58][59][60]. Among these, an excellent MR fluid candidate, CI particle, is used widely adopted owing to its high saturation magnetization and appropriate particle size.…”