Effect of Oleic Acid Coating of Iron Oxide Nanoparticles on Properties of Magnetic Polyamide-6 Nanocomposite

Abstract

This work reports the development and testing of a magnetic polymer (Polyamide 6, PA6) nanocomposite capable of melting when exposed to an external magnetic field. Addition of high concentrations of iron oxide nanoparticles (NPs) can induce quick melting but is detrimental to the mechanical properties of the polymer. To reduce the amount of NPs required for achieving efficient melting, they should be well dispersed in the polymer. In this study, the oleic acid loading on the surfaces of the NPs was varied to study the effect of variations in coatings on the dispersion in the polymer and on the polymer melting time. The NPs functionalized with oleic acid were added to melted monomer e-caprolactam and polymerized using ring-opening polymerization. The resulting PA6 nanocomposite was characterized by Fourier-transform infrared spectroscopy, differential scanning calorimetry, x-ray diffraction and transmission electron microscopy. The results confirmed that the PA6 nanocomposite showed a decrease of 8-10% in its glass-transition temperature compared to commercial PA6. The crystallinity of the synthesized samples were found to vary between 42% and 57%. The 55 wt.% oleic acid-loaded NPs were found to disperse most efficiently in the PA6 matrix; however, some large agglomerates were formed due to excessive oleic acid. Therefore, the 22 wt.% oleic acid coating showed overall superior dispersion. Additionally, the magnetic induction response was tested by observing a melt-characteristic of the magnetic polymer composite using a model setup. Oleic acid concentration is found to affect the dispersion, melting time and crystallinity of the nanocomposite.

Induction heating induced self-healing of nanocomposites based on surface-functionalized cationic iron oxide particles and polyelectrolytes

“…Low signal intensities indicate a small oleic acid concentration. 31 P NMR spectroscopy was conducted on the supernatant solutions of the functionalization reaction mixtures, showing residual unreacted phosphonic acid starting from sample 0.100 P@Fe x O y (see Figure S21), which means that the particle surface is saturated with these groups. Surface coverage was studied using TGA and CHN analysis.…”

“…Important in terms of magnetic properties are composition, size, morphology, and surface functionalization. [28][29][30][31] Superparamagnetism is limited to magnetite particles at the nanoscale, particularly below 25 nm. [32] This introduction of superparamagnetic properties, potentially offers the opportunity for spatially resolved healing with an alternating magnetic field (AMF).…”

Novel method of healing the fibre reinforced thermoplastic composite: A potential model for offshore applications

“…Together with crack-gap closing mechanism, the microwave source can be interfaced with electronic triggering mechanism to affect the self-healing in remotely located FRP components (17,20). Moreover, the healing can also be performed multiple times by applying micro-wave or magnetic stimuli (21,22).…”

Comparison of the Dielectric Properties of Ecoflex® with L,D-Poly(Lactic Acid) or Polycaprolactone in the Presence of SWCN or 5CB

“…Usually, oleic acid is used to better disperse the SWCN during sonication when preparing the hybrid layer [ 35 , 36 , 37 ]. Therefore, in this work, we decided to study the influence of oleic acid on the dielectric response of the created hybrid layers.…”