الفهرس | Only 14 pages are availabe for public view |
Abstract High-k materials (high permittivity ε’) are of extraordinary demand for the miniaturization of electronic devices. In particular high- k polymer / inorganic composites which can be tailored to the electromagnetic applications. Polyvinyl alcohol (PVA) as a host green biodegradable polymeric matrix was chosen to fabricate novel polymer nanocomposites with different concentrations of magnetite (Fe3O4) nanoparticles and different concentrations of barium titanate (BaTiO3) nanoparticles before and after treatment or modification with ionic liquid (IL) as a dopant using casting method. The particle size of magnetite (Fe3O4) nanoparticles and barium titanate (BaTiO3) nanoparticles were determined using the transmission electron microscope (TEM). The morphology and structural properties of those nanocomposites were inspected by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. SEM indicates good dispersion of Fe3O4 nanoparticles and ionic liquid treated BaTiO3 inside PVA matrix. Whereas, XRD data revealed a notable increase in the degree of crystallinity by increasing IL treated BaTiO3 loading. Fourier Transformation Infrared Spectroscopy (FTIR) of PVA through its respective functional groups was noticed by addition of Fe3O4 nanoparticles and BaTiO3 nanoparticles before and after modification as well. A considerable change in characteristic peaks in the FTIR spectra was detected. The mechanical parameters; tensile strength (σR), elongation (εR) and hardness (Hv)were also investigated. Mechanical properties investigations revealed that 10 (Fe3O4 / IL treated BaTiO3) wt% is the optimum concentration. Moreover, microhardness increases with the increase of the Fe3O4 content, as well as after modification of BaTiO3 with the ionic liquid. The magnetic properties were investigated by vibrating sample magnetometer (VSM) and the obtained data disclosed an enhancement in magnetic properties by the ionic liquid treatment and clearly demonstrate ferromagnetic behavior. This finding widens the application scope of PVA nanocomposites to include electromagnetic purposes. The dielectric properties of the PVA nanocomposites were investigated over wide frequency range (0.1Hz-1MHz). The presence of BaTiO3 and /or Fe3O4 significantly increased permittivity ’ and dielectric loss ” and enhance the ionic conductivity of the PVA. The role of treatment of BaTiO3 by ionic liquid on the later mentioned parameters was interpreted. The values of conductivity were found to be in range of 10-5 –10-9 S/cm, suggests the use of such composites for electrostatic dissipation applications. |