Effects of the Ferrits Addition on the Properties of Polyethylene Terephthalate

The products of composites material are very sesetive to many variables, such as manufacturing process, additive materials, .... etc. Filler or additive plays a major role to determine the formation of the properties and behavior of the composites. In this study, polyethylene terephthalate-based compounds were produced and characterized. The work is concerned to prepare samples of Polyethylene terephthalate (PET) zinc-ferrite (ZnFe2O4) with different addition ratio as zinc-ferrite (1, 2, 5, 10, 15 and 20) wt% obtained from mixing the solution with a hot pressing method applied under optimum conditions. The densities of the composites for all samples were calculated. Through the work the diffusion of zinc-ferrite into the grain of Polyethylene terephthalate has been noted. Structural properties are studied by using X-ray powder pattern, the results of the XRD diffraction analysis showed that the structure for pure PET has four broad peaks at the (2θ=16.46°,17.45°, 22.72°,25.98°). The non-crystalline behavior of the polymer and the ceramic compound indicates the presence of a crystalline phase with a single cubic structure with a space group fd-3m (227)) (a=b=c=8.44 Å, V=601.45 (Å)3). While adding zinc-ferrite to PET in different concentrations to obtain (PET / ZnFe2O4) composites material will increase the intensity of the X-ray peaks, and change the location of the peaks with the addition of zinc-ferrite. It is noted that X-ray diffraction patterns for PET / ZnFe2O4 (20%) indicates that there was no apparent variation of the patterns of pure Zn-ferrite ceramic diffraction which showed that the crystalline structure remains stable in PET / ZnFe2O4. In addition, the electrical properties of the compounds represented by the dielectric constant (real and imaginary), dielectric loss ( tanδ) and the A.C conductivity as a function of a range of frequencies (50Hz-1MHz) have been measured. The results indicated that these properties increase with increasing concentrations of ceramic addition. On the other hand, these properties decrease with increasing frequency due to the change in polarization mechanisms. It has been proven that these prepared superposed materials possess good stability properties in a wide range of frequencies, making these polymeric overlays of wide use in many applications. As for the measurements of Shore D hardness, it has been shown that the hardness of the compounds increases with increasing ceramic concentrations.


Introduction:
Composites are important and necessary materials today because of their benefits. Composites of polymer based such as matrix ceramics as a filler receive increased care due to their electrical and optical properties, such as angular acceleration for accelerometers, acoustic emission of sensors, integrated separation of capacitors, electronic packaging in some potential applications and optoelectronics as device elements such as LEDs and solar cells and laser diodes. Ceramic materials are usually brittle, and electrical insulation strength is low and requires high temperature. But then, the polymers are flexible and easy to handle easily at low temperatures and are displayed in a dielectric breakdown 1 . The incorporation of inorganic fillings into polymer matrices were the subject of many studies 2-6 . Gorrasi et al. 3 prepared and studied the physical properties of a PET-based composite material reinforced with nanotubes scattered in fancy locations for packaging applications. According to these authors, the behavior of the compound was similar to that observed in the literature. Kilinc et al. 4 examined the retardants of flame and tensile properties of the PET composite material containing boron and phosphorous additives, which were processed by the extrusion and then formed into the injection machine, authors reported high flame retardation and strength improvement after additions. However, other researchers have investigated properties derived from the addition of Fe 2 O 3 , TiO 2 CaCO 3 , ZnO and TiO 2 nanofillers 5 . Chae et al. 6 examined the biological and thermal properties of highly concentration ferrous nanoparticles with PET, their results showed that nanoparticles ferrite played an important role in crystallization of PET polymer, due to heterogeneous nucleation. As a result, other properties were affected, such as the thermal stability of the matrix, heat permeability and low propagation of the decomposition products. Rupture energy and tensile strength of hybrid poly (methyl vinyl siloxane) fortified with the short PET fibers and wollastonite bristles were studied by Fu et al. 7 , in which authors observed an increase in strength with an increase in the wollastonite concentration, from 5 to 45 wt.%. The opposite effect is related to the change in the interface properties between the PET fibers and the matrix by the incorporation of the wollastonite bristles. However, the interfacial friction stress caused by the shrinkage of the matrix during the curing process may be causing the compound to be reinforced 7 . Zn-Ferrite is one of the most important non organic complete, it is used in many applied material devices since 60 years ago. The general formula is Zn x Fe 3-x O 4 which consists of Fe and Zn with oxygen atoms 8 . The Ferrite complex is prepared from reaction oxide of Iron and Zinc oxide with higher temperature. The spinal Zinc Ferrite is a sold material and non-Solute in water, acid and Alkaline and acid materials (9). Zinc ferrite has good higher reflection to use Dyes (experiments) in much more applicaions that have stability heating 10 . On the other hand, it was added to many paintings to produce forcing corrosion by environmental effect 11 . Zinc ferrite has high electric resistant and has high dielectric properties and optical heat, the magnetic properties is good practice such as resistant of damage and good emission. The coefficient of heat extended hourly and has energy transfer with good efficiency. All these properties made Zinc Ferrite complex stable with different applications in technology material, sensor, microwave, and for battery and magnetic mater [12][13][14][15] . Although the ceramic has higher solid electric penetration, and corrosion, it is usually active for electric and heating transfer and has high resistant for higher temperature compared with polymer 16 . The mechanical properties for ceramic material were very complex with ductile and easy to break under any strains compared with polymer which has light weight, lower density and elastic but usually tearing materials 17,18 . However, the produced decomposition material designed for valise application resulted in enforcing the polymer by ceramic mater to get good dielectic properties and mechanical force. It was important in many electronic instruments needed in material stability and has higher dielectric with a good control in heat treatment to produce good surface and lower vacancies 10, 11 D.K. Das et.al 18 mixed ceramics material with a higher dielectric constant (PZT) in polymer matrix to produce a composite material which has a large dielectric constant. Li -Zhang et.al 19 prepared composite material produced in that phase from polymer and ceramic for a small microwave antenna, due to the good electro chemical and polarity properties. The permittivity of composite was increased from 3.45 to 11.87 whereas the tan remained constant at 0.0016. Samara Jasim Mohammed 20 studied some dielectric properties for polymerceramic composite, (PZT)-( PVC) using solid solvent for preparing composite samples . It was noticed that the dielectric constant value decreased with ratio of Ceramic (PZT). The decreasing of dielectric is small at low ratios 15% and 30%, while it increased largely at 0.45% and 60% ratio for PZT. However, the tangent of angle tan was calculated for polymer and composite, it has been shown that tan increased with increasing the ratio of (PZT). Samara Jasi Mohammed et.al 21 prepared micro polymer composite material adding Titian di oxide (TiO2) with grain size (75-150) m to epoxy rating for different concentrations. The strength of the fracture and hardness were studied for composites materiales and it was observed the increasing of the hardness with the wieght ratios of ceramics. Kesarwani et.al 22

Material Methods:
The experimental process starts with preparing the Zn Fe 2 O 4 complex material by solid state reaction method 24 . ZnO and Fe 2 O 3 were used as elementary materials to prepare the ZnFe 2 O 4 by weighting equivalent quantity in molaric ratio (1:1). Then, they were mixed with each other by adding acetone to give a good homogenous mixed material. The resulted homogenous material was heated in electric furnace to sintering in air at 1100 C° temperature for 2 hours and cooled to room temperature. The homogenous material produced Zn-ferrite phase using x-ray diffraction.
The PET polymer was dissolved in dichloromethane and then the zincferrite was added to polymer in volume fractions (1, 2, 5, 10, 15 and 20) wt % and mixed well in a mortar. These composites were reformed by using a hot pressing method.
The density of the composites was measured by Archimedes Method 12 . The weight of the dry samples was estimated by a sensitive balance and the samples were immersed in distilled water and boiled for (4 hr). The samples were immersed in water for (6 hr) and then studied. The weight of each sample was suspended in its submerged basket with distilled water by the sensitive balance. The samples were then dried and the water was removed from the surface of the samples. The samples were weighed directly by a sensitive balance after drying. This process must be completed quickly to reduce the error rate. The density of the composites has been calculated from the following relationship 25 .
Where: D is the density of distilled water (1gm/cm³), w d (gm) is the weight of the dry sample, Wn (gm) is the weight of the sample suspended and immersed in distilled water, and Ws (gm) is the weight of the sample in saturation condition with distilled water. The structure of composite materials were investigated by x-ray diffraction with cu kα radiation source (ƛ = 1.54056A°) for a scan range 2 from (10°-80°). Dielectric constant, dielectric loose tangent and Ac conductivity for composites were studied by using LCR meter type (8105G( 120) 5M Hz, Taiwan, LRC) within the frequency range (50 Hz-1MHz). The hardness shore D was measured to different samples using achiness shore device establishment.

Results and Discussion:
The densities of the composites were measured and calculated by Archimedes method. The spread of zincferrite in the PET polymer led to a change in the density of the coposite. There are two reasons for changing the composite density; the first is due to the large molecular weight of ferrite compared with the polymer. The second reason is the large volum of PET particles. The reason for the discrepancy in the values of the densities is the additions create a dangling bonds that reduce the density of the composite in some samples (2 & 3%), and this is a result of the stability of the crystal structure 26 , as shown in Fig. 1 and Table 1.

Figure 1.The densities of the PET/ Zn-ferrite as a function of addition Zn-Ferrite wt%
The structure of composite materials is investigated and illustrated in Fig. 2. The x-ray diffraction diagram for pure crystalline compound Zn-ferrite that the pattern of diffraction X-rays of the pure crystal Zn-ferrite includes 12 basic narrow peaks that are due to the crystalline behavior of the Zn-ferrite. Where the X-ray diffraction pattern indicates the presence of a crystalline phase with one cubic structure with a space group fd-3m (227)) (a = b = c = 8.44 A °, V = 601.45 A °), this was calculated using Brack's law 27 . As for Fig. 3, it shows the X-ray diffraction patterns of the pure polymer, where it shows that there are four broad peaks at (2θ = 16.46 °, 17.45 °, 22.72 °, 25.98 °). This indicates that the composition is polycrystalline and after its comparison with the primary sources, which showed the pattern is due to the pure polymer (PET), which promotes the amorphous behavior of the polymer. This is consistent with long-term structural disorder 28 .

°) XRD of PET
All diffraction peaks in this paper are in good agreement with the data base comments card No-(00-022-1012) 21 as well as diffraction patterns of xray ceramic-polymer composites (PET/ ZnFe 2 O 4 with (1,2,5,10,15,20 wt%). There are differences in x-ray diffraction pattern of the pure compound, Zn-ferrite which also shows that the cubic structure of the compound Zn-ferrite is stable in the composite. However, we noted from the x-ray diffraction diagram of the (PET/ ZnFe 2 O 4 ) polymer -ceramic composite that there is no undesirable interaction and this is evident in Fig. 4 that the stronger peak occurs at the angle 2 =25.9° of polymer (PET). The intensities of the diffraction peaks for the polymer (PET) are dispersing with the increasing of the ceramic Zn-Ferrite concentration. In addition to this, it is observed from Fig. 4 that there is a decrease in the intensity of the peaks and their width, this indicates that the increase in the crystal structure occurs whenever the percentage of ferrite increases 29 .

Analysis of Dielectric properties:
The variations in the real part (έ) and imaginary part (ε˝) of dielectric constant for polymer-ceramic (PET/ ZnFe 2 O 4 ) samples as a function of frequency at room temperature are shown in Figs. 5 and 6, it has been observed that a decrease in dielectric constant (έ) and loss (ε˝) leads to decreasing frequency at room temperature without the effect of addition ZnFe 2 O 4 . From these Figures, an increase in the dielectric constant (έ) and a loss (ε˝) at low frequencies at 50000 Hz at room temperature are observed due to the lack of work of polarization mechanisms at these low frequencies. The dielectric constant (έ) and a loss (ε˝) decrease sharply at the range of frequency over (500000 Hz). The real part (έ) of the dielectric constant (έ) gives a part of the volume of energy stored inside the material when exposed to an electric field, and the most likely place to store this energy is within the grain sites (between the grains). The imaginary part of the dielectric constant (ε˝) indicates the absorption and attenuation of energy across the interfaces under an external electrical field. Examples of interfaces are grain boundaries, localized defects and localized charge densities at the defect sites and at grain boundaries 30 .
On the other hand, we can note from Fig. 7 that the lost tangent will decrease with increasing frequency. This is possible to be produced from the decrease in electrical conductivity of the composites with increasing frequency as shown in Fig. 8. Also, it has been noted that the frequency depends on the dielectric constant and (tan ) and it increases with the increase of the Zn-Ferrite content. This increase in dielectric constant, (tan ) and dielectric loss with increased Zn-Ferrite content explains the charging polarization at interface and the dipole polarization intrinsic with in composites in applied fields 30 .
These phenomena appear in heterogeneous systems such as polymer compositions due to the accumulation of electrical charge at the interface of the boundary and the formation of large dipoles. Therefore, the degree of polarization with composite increases with increasing Zn-Ferrite content of ceramic and this enhances the dielectric constant of the composites. Varying the logarithm of Ac conductivity as a function of frequency for PET/ ZnFe 2 O 4 is shown in Fig. 8. This Figure illustrates that the increase ceramic ZnFe 2 O 4 produce increasing the AC conductivity of the composite due to the decreasing in the crystallization degree of the composites which is confirmed by x-ray diffraction analysis. The increasing of the non-crystallized regions will led to produce a faster polymer chains . This will make the movement of ions easy between chain so the ac conductivity of the (PET/ZnFe 2 O 4 ) will increase. Fig. 8 shows that the AC conductivity decreases with increasing frequency for the PET/ ZnFe 2 O 4 , and the ratio of the weight (20 wt%) of the ceramic ZnFe 2 O 4 indicates significant increase in the AC conductivity at high frequencies, which related to the relaxation (such as Deby) that occurs in such materials.
Hardness shore D as a function of Znferrite concentration are shown in Fig.9 and Table 2, where it is noted from the Figure that the values of shore hardness D increase sharply from 68.7 to 74.8 when adding Zn -ferrite 0 to15 wt%, but decrease gradually as the concentration of Zn -ferrite increases above 15 wt% until it becomes 72.8 at 20 wt%. This is because at weight ratio (15 wt %) has a is good diffuse of the Zn Fe2 O4 particles in the matrix (PET) polymer. These strangles affect the properties of the mechanical composites and the hardness. In the case of the (20 wt.%) ratio, the shore hardness D decreases the appearance of the clusters which reduces the mechanical properties.

Conclusions:
The effect of adding Zn-ferrite ceramics to the PET polymer to obtain the PET /ZnFe 2 O 4 composite utilizing solid-state reaction has been investigated. The samples are mixed and compressed using a cold pressure method and then treated with heat. X-ray diffraction pattern from the Zn ceramics -Ferrite shows single-phase cubic structure. XRD polymer pattern (PET) demonstrates the presence of an Anorthic structure. Dielectric constant, tanδ dielectric loss and dielectric loss, increase with increasing zinc ferrite ceramic content. The AC conductivity of PET / ZnFe2O4polymer ceramic compounds increases as the ceramic content of Zn-ferrite increases. The polymer ceramic composite PET / ZnFe 2 O 4 shows that conductivity increases significantly with increasing frequency. Shore D hardness increases with increasing Zn-Ferrite ceramic content in the PET matrix. High dielectric constant and static dielectric properties make PET / ZnFe 2 O 4 compounds very useful in industrial applications such as magnetic materials, gas sensors, catalysts, photocatalysts, and absorbent materials.