Preparation and characterization of multifunctional magnet/polymer composites

Abstract

In recent years, the development of personal computer and electronic equipments and devices is proceeding in the direction of miniaturization with increasing functionality. Hence, a great deal of interest is emphasized on the research of multifunctional materials

In this project, Ni-Zn ferrite (NZF) fillers with ferromagnetic properties will be incorporated into poly (vinylidene fluoride-hexafluoropropylene), PVDF-HFP, with ferroelectric properties. The dual properties favour the potential of forming multiferroic materials with high performance and multifunctionality. And this enables the multifunctional materials to work both as capacitors and inductors.

Ni-Zn ferrite/PVDF-HFP composite were studied and investigated by having different mass percentage of NZF powder dispersed homogeneously with the PVDF-HFP powder, before hot press into thin films form. Modification was done to both the polymeric matrix and NZF filler by blending PVDF-HFP with poly (methyl methacrylate), PMMA, and coating NZF with polyvinyl alcohol, PVA, respectively, to achieve better morphology, thermomechanical properties, magnetic and ferroelectric properties.

FTIR spectrum showed good miscibility between PVDF-HFP and PMMA polymer, and XRD results showed the presence of NZF in the films. Addition of more than 20wt% of PMMA will significantly lower the degradation temperature, storage modulus, dielectric properties but enhance the tan delta of films. PVA coated NZF enhanced the magnetic properties, crystallization and melting temperature but lowered the glass transition temperature. Films with 5.0wt% NZF displayed the best magnetic properties and highest performance for magnetization can be achieved slightly after the glass transition temperature. P(VdF-HFP) will be the ideal polymeric matrix for microelectronics components due to its high dielectric constant. Films with different weight percentage of NZF displayed comparable dielectric constant and loss factor, thus it can be concluded that NZF filler will not affect the dielectric properties to a great extent.