Influence of K2CrO4Doping on the Structural, Optical and Dielectric Properties of Polyvinyl Alcohol/K2CrO4Composite Films

J of Applied Polymer Sci

Ahamed

Sadasivuni

et al. 2016

Self Cite

In the present study, fumed silica (SiO2) nanoparticle reinforced poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) blend nanocomposite films were prepared via a simple solution‐blending technique. Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to elucidate the successful incorporation of SiO2 nanoparticles in the PVA/PVP blend matrix. A thermogravimetric analyzer was used to evaluate the thermal stability of the nanocomposites. The dielectric properties such as dielectric constant (ɛ) and dielectric loss (tan δ) of the PVA/PVP/SiO2 nanocomposite films were evaluated in the broadband frequency range of 10−2 Hz to 20 MHz and for temperatures in the range 40–150 °C. The FTIR and UV–vis spectroscopy results implied the presence of hydrogen bonding interaction between SiO2 and the PVA/PVP blend matrix. The XRD and SEM results revealed that SiO2 nanoparticles were uniformly dispersed in the PVA/PVP blend matrix. The dielectric property analysis revealed that the dielectric constant values of the nanocomposites are higher than those of PVA/PVP blends. The maximum dielectric constant and the dielectric loss were 125 (10−2 Hz, 150 °C) and 1.1 (10−2 Hz, 70 °C), respectively, for PVA/PVP/SiO2 nanocomposites with 25 wt % SiO2 content. These results enable the preparation of dielectric nanocomposites using a facile solution‐casting method that exhibit the desirable dielectric performance for flexible organic electronics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44427.

Section: Resultsmentioning

confidence: 99%

Fumed SiO₂ nanoparticle reinforced biopolymer blend nanocomposites with high dielectric constant and low dielectric loss for flexible organic electronics

J of Applied Polymer Sci

Ahamed

Sadasivuni

et al. 2016

Self Cite

“…These interactions can induce changes in the vibrational modes of the polymer electrolytes [35]. The FTIR spectra of PVA/ PVP blend and PVA/PVP/Li 2 CO 3 polymer blend electrolyte films are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The first step of decomposition was observed at the temperature slightly below 100°C which could be attributed to the evaporation of superficial or residual moisture in the sample [3]. The second step of decomposition was observed in the temperature range 100-240°C which can be attributed to the decomposition of the main chain of polymers [35]. The third step of decomposition was observed in the region 240-350°C which could be attributed to the decomposition of Li 2 CO 3 salt.…”

Section: Thermal Analysismentioning

confidence: 91%

Impedance spectroscopy, ionic conductivity and dielectric studies of new Li+ ion conducting polymer blend electrolytes based on biodegradable polymers for solid state battery applications

J Mater Sci: Mater Electron

Ahamed

Polu³

et al. 2016

Self Cite

New solid polymer blend electrolyte films based on biodegradable polymer blend comprising of polyvinyl alcohol (PVA) and poly (N-vinyl pyrrolidone) (PVP) doped with different wt% of lithium carbonate (Li 2 CO 3 ) salt have been prepared by solution casting method. The resulting PVA/PVP/Li 2 CO 3 polymer blend electrolyte films have been characterized by various analytical techniques such as FTIR, UV-vis, XRD, TGA, polarized optical microscopy and scanning electron microscopy. The FTIR and XRD analysis confirmed the complex formation between PVA/ PVP blend and Li 2 CO 3 salt. The ionic conductivity and the dielectric properties of PVA/PVP/Li 2 CO 3 polymer blend electrolyte films were investigated using an impedance spectroscopy. It was observed that the ionic conductivity of PVA/PVP/Li 2 CO 3 electrolyte system increases as a function of Li 2 CO 3 concentration. The highest ionic conductivity was found to be 1.15 9 10 -5 S cm -1 for polymer blend electrolyte with 20 wt% Li 2 CO 3 content. On the other hand, the dielectric results revealed the non-Debye type of behaviour. The dielectric constant values indicate a strong dielectric dispersion in the studied frequency range which increases as the Li 2 CO 3 content increases. The dielectric constant as high as 1200 (e = 1201.57, 50 Hz, 150°C) and the dielectric loss well below 4 (tan d = 3.94, 50 Hz, 150°C) were obtained for polymer blend electrolytes with 25 wt% Li 2 CO 3 salt. Thus, the results obtained in the present study suggest that the PVA/PVP/ Li 2 CO 3 polymer blend electrolyte system seems to be a promising candidate for solid state battery applications.

“…The first decomposition stage appears between the temperatures 48°C and 134°C (weight loss is in the range 3.06%-3.65%) which is ascribed to the removal of adsorbed water present in the nanocomposites. The second stage of decomposition is located in the temperature range 147°C-403°C which could be due to the bond scission and splitting of the monomer unit in the backbone of PVA [58]. The weight loss in the second decomposition stage is observed to be in the range 52.99%-67.40%.…”

Section: Xrd Analysismentioning

confidence: 95%

“…Moreover, it has been noticed that the intensity of the diffraction peak corresponding to PVA is decreased with an increase in the NiS NPs loading in the nanocomposites. This may be due to the possible intermolecular interactions between the nanofiller and the host polymer matrix which tends to decrease within the polymer chains and therefore the degree of crystallinity [58][59][60]. figure 5(a)) depict two weight loss stages (overall weight loss is about 36.06%).…”

Section: Xrd Analysismentioning

confidence: 99%

Enhanced dielectric properties of green synthesized Nickel Sulphide (NiS) nanoparticles integrated polyvinylalcohol nanocomposites*

Reddy

Kovařík

et al. 2020

Mater. Res. Express

Self Cite

A green synthesis approach has been adopted to prepare nickel sulphide nanoparticles (NiS NPs) using banana peel extract (BPE) as a reducing and capping agent. Polyvinyl alcohol (PVA)/NiS nanocomposite films were fabricated using a cost-effective solution casting technique by dispersing different contents of NiS NPs (0-3 wt%) in the PVA matrix. Various characterization techniques were employed to analyze the structural, thermal and morphological properties of the PVA/NiS nanocomposite films. Further, the dielectric behaviour of these nanocomposite films was investigated at frequency range 50 Hz-20 MHz and in the temperature range 40°C-140°C. Also, there exists a significant interaction between the polymer matrix and the nanofiller as evident from the notable improvement in the dielectric properties of the nanocomposites. The dielectric constant (ε) value of PVA/NiS nanocomposite film with 3 wt % NiS NPs loading was found to be 154.55 at 50 Hz and at 140°C which is 22 times greater than the dielectric constant value of neat PVA (6.90). These results suggest that NiS NPs were dispersed homogeneously in the PVA matrix.Among various polymers used for the fabrication of PNCs, polyvinyl alcohol (PVA) is most often preferred as a host matrix owing to its excellent film-forming ability, higher dielectric strength, the capability to form strong hydrogen bonding, easy processability, excellent chemical stability, and highly durable nature [17]. PVA has been employed for various applications such as in battery components, packaging, textile applications in the microelectronic industry, electromagnetic interference applications and so on [17,18]. Several research groups reported the dielectric properties of the PVA based nanocomposites [19][20][21]. With this inspiration, in the present study PVA has been chosen as a host polymer to synthesize PVA based nanocomposites. Now a day, more attention has been focussed on metal sulphide nanostructures because of their unique properties and applications [22]. Among these, nickel sulphide (NiS) has been mostly investigated because of its simple production, affordable price and high electronic conductivity [23,24]. It exhibits complicated electrical, optical, structural, compositional and magnetic phase behaviour [25]. Also due to the possession of multi-phases, binary Ni-S systems such as NiS 2 , Ni 3 S 4 , Ni 9 S 8 , Ni 7 S 6 , Ni 6 S 5 , Ni 4 S 3+x , Ni 3 S 2 , and Ni 3+x S 2 have become fascinated materials [26]. NiS NPs exhibit different shapes such as layer-rolled structures, urchin-like nanocrystallites, flower-like architectures, hollow spheres, nanoframes, nanorods, and nanospheres etc [27,28].Recently, increased attention has been given to the green approach for the synthesis of NPs because of its several advantages [29][30][31][32]. For the synthesis of NPs, the plant extracts which serve as reducing/capping agents are considered to be more beneficial than remaining techniques [33]. Several researchers reported the synthesis of metal sulphide NPs through a green synthesis a...