New Fabrication (PVA-PVP-C. B) Nanocomposites: Structural and Electrical Properties

In this present study, polymer blend (PVA-PVP)-Carbon black (C. B N375) nanocomposites have been investigated. The (PVA-PVP-C. B) nanocomposites are organized by via casting procedure. The optical microscope, FTIR and electrical properties have been studied. The constant of dielectric with the dielectric loss of the samples were reduced with increasing the value of frequency during the application of electric field, while an increasing in the A. C electrical conductivity results existed with the rising the value of the frequency. The electrical conductivity (A. C), dielectric loss and constant of all the samples were increased with the increasing of the carbon black concentrations.


Introduction
Nanocomposites are ingredients with high enactment show unusual stuff combinations [1]. With the fastest request to be in elastomers and engineering plastics, their possibilities are so outstanding that they are beneficial in many ranging areas from packaging to different applications [2][3][4]. Nanotechnology includes the manufacturing and nanocomposites application proposal new technics and chances of trade for several subdivisions of the automotive, aerospace, superconductor, electronics, physical and chemical at rulers reaching from singular molecules or atoms to submicron dimensions [5][6][7]. It is broadly felt that nanotechnology is the next manufacturing revolt [8,9].
Nanocomposites polymers containing polymers organic and nanoparticles inorganic in a nano-scale region signify novel types of resources that have interested significant interest in last year's [10][11][12]. These composites materials differ from unpolluted polymers concerning some of the chemical and physical properties [13,14]. The influences of impurity polymers on the polymer properties, bring more advantages and make it able to the enhancement of desirable properties. That could be very important and useful for the variable and wide applicant in several kinds of applications [15]. The combination of nanoparticles in polymers matrix offers the possibility of substantial's improvement to the optical possessions of the material with individual minor amounts on the nanoparticle [16]. Since they can affect strongly the physical, one advantage of nanoparticles, as polymer additive appears comparing to oldstyle additive, loadings requirements are fairly low [13,17]. The polymers' optical properties institute 2 significant aspects in the study of electronics transitions and the possibilities of their applications as an optical filter. The pieces of information about the electronics structures of amorphous and crystalline semiconductors typically accrued from the study of optical property in extensive frequency ranges [5]. Polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) are comprised in the lists of synthetics polymer used in medicines. PVP has a decent repute owing to its unresolved absorptions and complex ability, while PVA is used as composites with other material to improve its property, offerings significant structures, recognized fine processability on sample formations [18]. Additionally, these synthetics polymers are easy dissolved in water that give amazing characteristics for film formations. However, these characteristics are a difficulty as the materials are dissolved in contact with fluid into the mean form [19]. Dissimilar carbon black grades are shaped by the chemical decomposition of hydrocarbons at the raised temperature. The most wanted enforcing fillers where resistances to abrasions, cutting and aged must be at an extreme [20]. The four chief processes of the formations of four types of carbon black that are Lamp-black, Channel-black, Furnace black such as, (N110 to N762) with thermal black for instance, (N990 and N991) [21][22][23][24]. The electrical property deliberate in this research such as The constant of dielectric έ is determined by [5,25] Where Cp, d and A mean the capacity, thickness of the sample and surface area, respectively. Whereas, ε҆ ֞ is represented the Dielectric loss is [25]: Where the metric of loss is represented by tan δ. The equation below is used to calculate the AC conductivity [26].
The material used (PVA) the polymer is the largest synthesis and water-soluble polymers shaped in the world founded on volumes. The melting point of PVA is 230 0C and its molecular weight (18000 g/ mol). The provenance of PVA is Spain Industrial development, PVP is a white and hygroscopic powder with a weak characteristics order Provenance of PVP is Anhui Leaf chem. Co., Ltd, China (mainland) and high purity (99.8%). The melting point of PVP is (150-180) 0C. Carbon black (C.B) (N375 -32 nm) abounding by Doudah, Iran. It is inspected in agreement with DBP absorption (ASTM D 136) and Iodine absorptions (ASTM D 135) and preparations of (PVA-PVP-C.B) nanocomposites and studies the optical and structural possessions. The matrix polymer has been prepared by using PVA (90 wt. %), and polyvinyl pyrrolidone (10 wt.%)) as a matrix. The polymers are liquefied in water distill with magnetic stirrers in mixing procedure to get uniform solutions. The C.B nanoparticles added with different weight percentages to the solution were (0,5, 1, 1.5 and 2) wt.%. In order to prepare the (PVA-PVP-C.B) nanocomposites using the casting method. wt.% C.B nanoparticles. In Figure 2, the images of (PVA-PVP-C.B) nanocomposites film at the energy of magnifications for a specimen of distinct level (100x) were exhibited a good homogeneity and fine distributions of carbon black. When carbon black nanoparticles are increasingly presenting moves of PVA with PVP. The concentration of carbon black nanoparticles presented an impact factor to form a significant interaction network within polymers when the concentration increased to 0.02 wt % of the (PVA-PVP-C.B) nanocomposites. The formed network included several tracks within the samples that could help to enables carriers of charging cross these tracks through the polymer matrix in the nanocomposites [22].  Figure (4). Where, in the low-frequency range, the dielectric constant exhibited the higher values at low-frequency range and the higher dielectric constant was due to Maxwell-Wagner polarization, whereas this went to reduce with an increase in the frequency. This behavior was similar for all samples.

Results and Discussions
Interfaces of insulator conductor have originated this kind of polarization originates, where at the interfaces, this space charges accumulation or dipoles may result in this interfacial polarization. Where there is plenty of time at low-frequency regions of the space charges to react and the applied electric field, whereas it is too quick to react to the higher frequency range and does not exist of the polarization effect. Meanwhile, other polarization types are presented at high frequencies. In comparison, a slightly reacts of the ionic polarization variation in the field frequencies to the electronic polarization that could be related to the greater mass of ion compared to the electron. Even at high frequency, the electrons respond to the field vibrations. At higher frequencies only, the low electron mass helped to the electronic polarization and turned the dielectric constant about a constant of the all nanocomposites [27,29].   Figures (5, 6), the dielectric loss exhibited a reduction decreases in the value with rise in frequency. At low frequency, the polymer chain displayed the highly mobile charge carriers, whereas at high frequency, the space charges are noted not to react through the electric field and because the reduction in polarization led to the accumulation of the charge, as well as the dielectric loss, is reduction. That was generally lead to loss of the power in the dielectric material. Whereas, the dielectric loss of (PVA-PVP-C.B) nanocomposites is approximately constant within the rise of the value of frequency to 1 MHz.
Additionally, the high frequencies attributed the mechanisms of other polarization types. The contribution increasing the loading ration of C.B nanoparticles was responsible of improve the dielectric loss due to the rise of the ionic charge carriers, as revealed in Figures (5 and 6), in agreement with other finding [27,29].  nanoparticles. Figures (7 and 8) exhibit the AC electrical conductivity for (PVA-PVP-C.B) nanocomposites as a function of frequency at 100Hz and 25 o C, respectively. The finding exhibited an improvement of the electrical conductivity with the frequency of all the nanocomposites, this is because of the carried charge hopping over the conducting networks that were shaped as a consequence of polarity. At low-frequency region, the interfacial polarization is attributed to the improvement in the AC electrical conductivity with angular frequency, whereas at intermediate besides higher frequencies, the tunneling/ hopping between two equilibrium sites is considered the main reason to enhance the conductivity during the electrons or atoms motion. In general, in the case of the band conduction, the AC conductivity is reduced with the rise of the value of frequency, while it improves with if the frequency is increased in the hopping conduction case.
From figures (7,8), it can be shown an increasing the loading ratio of (C.B) nanoparticles is associated to improve in the conductivity of nanocomposites as an outcome of the rice of the ionic charge carriers, in addition to the (C.B) nanoparticles formed a continuous network of ions inside the samples [12,13].

Conclusions
The dielectric constant of the samples reduced with the rise of the frequency of the applied electric field as well as this behavior was similar for the dielectric loss. The A.C electrical conductivity was enhanced after increasing the value of the frequency. The A.C electrical conductivity of (PVA-PVP-C.B) nanocomposites and dielectric constant and the dielectric loss for all concentrations increases with the increasing the ratio of carbon black.