Influence of ZnO nanoadditives on the structural characteristics and dielectric properties of PVA

Author(s):  
E. Abdeltwab ◽  
A. Atta

In this study, different percentages of semiconducting zinc oxide nanoparticles (ZnONPs) are mixed with polyvinyl alcohol (PVA) to create flexible ZnO/PVA polymer nanocomposite films. The characteristics of the prepared films are investigated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The XRD pattern shows that the ZnO/PVA composite films were successfully synthesized; while the SEM images show that the ZnONPs are homogeneously dispersed in the PVA polymer chain. Moreover, the DSC indicates an improvement in the thermal stability behavior with increased of ZnONPs concentration. The electrical conductivity, dielectric properties, electric modulus behavior, and the energy density efficiency of the pristine PVA and ZnO/PVA composite films are determined using an LCR meter in the frequency range 102–106 Hz. The dielectric constant of the composite film increased from 0.185 for pristine PVA to 1.389 for 9%ZnO/PVA, and the conductivity is improved from [Formula: see text] S/cm to [Formula: see text] S/cm. This work would open the road for utilizing ZnO/PVA flexible nanocomposite films for wide range of applications such as batteries, super-capacitor and energy storage devices.

2021 ◽  
Author(s):  
Rashmi Adoor ◽  
Narasimha Ayachit ◽  
Kishor Upadhyaya ◽  
R.F. Bhajantri ◽  
Mallikarjun Anandalli

Abstract Carbon nanosphere / Polyvinyl alcohol/Polyacrylamide (CNS/PVA/PAM) nanocomposite films prepared via a solution casting method were studied for their structural and dielectric properties. Scanning Electron Microscopy (SEM) images of the CNS/PVA/PAM blends reveal the formation of circular islands of CNS and uniform blending with PVA/PAM matrix. XRD pattern shows a higher value with increase in blending ratio of PVA with CNS. The interaction of the dispersed and preformed CNS particles with the PVA/PAM chain was confirmed by the corresponding vibrational signaturing of PVA/PAM through FTIR. The dielectric constant increased from [K = 134, 2K Hz, 305 Kelvin] to [K = 438, 2KHz, 333 Kelvin] and the composite films exhibited a high increase in the energy storage efficiency upto 75% (at 2KHz) in the case of 4%CNS /PVA/PAM 50:50 sample.


RSC Advances ◽  
2015 ◽  
Vol 5 (56) ◽  
pp. 44749-44755 ◽  
Author(s):  
Yun-Hui Wu ◽  
Jun-Wei Zha ◽  
Zhi-Qiang Yao ◽  
Fang Sun ◽  
Robert K. Y. Li ◽  
...  

PI composite films with electrospun BT fibers were fabricated using the in situ dispersion polymerization method. The microstructures, thermal and dielectric properties of the BT fibers and composite films were investigated.


Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1125-1134 ◽  
Author(s):  
Vesna Žepič ◽  
Ida Poljanšek ◽  
Primož Oven ◽  
Matjaž Čop

Abstract Freeze dried nanofibrils were acetylated in a heterogeneous system with acetic anhydride, pyridine, and dimethylformamide and the obtained acetylated cellulose nanofibrils (CNFac) were combined with poly(lactic acid) (PLA) to a composite. CNFac with its partially hydrophobic surface showed a good compatibility with PLA resulting in composite films with improved properties. Tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EB) of PLA/CNF increased significantly when 2–5% of CNFac was added to the PLA matrix, while the addition of 10% and higher amounts CNFac decreased the EB at a higher TS and MOE. Mechanical parameters did not improve in the case of unmodified CNF addition. The addition of CNFac maintained transparency and had absorbance values between those of pure PLA film and PLA film with 2% CNF, while films formed with the addition of 5 and 10% of CNF were less transparent. The addition of CNF did not essentially affect the thermal properties of nanocomposite films. The addition of 2–10% of CNFac increased the enthalpy and maximal temperature of cold crystallization as opposed to higher loading of CNFac. The results of differential scanning calorimetry (DSC) coincide with those of the mechanical properties. Tailoring properties of PLA/CNF are only reproducible in case of homogenously distributed CNF within the PLA matrix and by an improved interphase adhesion between PLA and CNFac.


2001 ◽  
Vol 706 ◽  
Author(s):  
Cheol Park ◽  
Zoubeida Ounaies ◽  
Kent A. Watson ◽  
Kristin Pawlowski ◽  
Sharon E. Lowther ◽  
...  

AbstractPolymer-single wall carbon nanotube (SWNT) composite films were prepared and characterized as part of an effort to develop polymeric materials with improved combinations of properties for potential use on future spacecraft. Next generation spacecraft will require ultra-lightweight materials that possess specific and unique combinations of properties such as radiation and atomic oxygen resistance, low solar absorptivity, high thermal emissitivity, electrical conductivity, tear resistance, ability to be folded and seamed, and good mechanical properties. The objective of this work is to incorporate sufficient electrical conductivity into space durable polyimides to mitigate static charge build-up. The challenge is to obtain this level of conductivity (10-8 S/cm) without degrading other properties of importance, particularly optical transparency. Several different approaches were attempted to fully disperse the SWNTs into the polymer matrix. These included high shear mixing, sonication, and synthesizing the polymers in the presence of pre-dispersed SWNTs. Acceptable levels of conductivity were obtained at loading levels less than one tenth weight percent SWNT without significantly sacrificing optical properties. Characterization of the nanocomposite films and the effect of SWNT concentration and dispersion on the conductivity, solar absorptivity, thermal emissivity, mechanical and thermal properties were discussed. Fibers and non-woven porous mats of SWNT reinforced polymer nanocomposite were produced using electrospinning.


2014 ◽  
Vol 989-994 ◽  
pp. 242-245 ◽  
Author(s):  
Ya Jun Wang ◽  
Jian Wen Zhai ◽  
Fang Fang Wang ◽  
Chang Gen Feng

Conductive particle fillers could improve the dielectric properties of the polymer matrix. By solvent casting method, different volume fraction of nanosilver particles were added into the PVDF film to prepare Ag/PVDF composite film so as to increase the dielectric properties of the materials. SEM was used to analyze the microstructure of the films. SEM images show that nanoAg filler particles were uniformly distributed throughout the whole matrix of the composite films. Dielectric property tests show that with the increase of nanoAg content, the dielectric constants of the composites increase first and decrease later while the dielectric losses decrease first and increase later. In the case of the optimal 17vol% Ag content, the dielectric constant of the composite film is the highest (14.5 at 100 Hz) with lower dielectric loss, and the energy storage density is relatively high (0.340 J·cm−3).


2010 ◽  
Vol 25 (4) ◽  
pp. 658-664 ◽  
Author(s):  
Chang-An Wang ◽  
Keyu Chen ◽  
Yong Huang ◽  
Huirong Le

Layer-structured polypyrrole/montmorillonite (PPy/MMT) naoncomposite films were synthesized by the electrodeposition method. The fabricated free-standing films consist of about 0∼2 wt% Na+-montmorillonite (NMMT). The thickness of films could be controlled by deposition time. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to observe the microstructure of the films. After MMT was introduced into the PPy matrix, the interspace between PPy chains decreased, according to the XRD results. The layered structure of the films was observed from the SEM images. Tensile and nanoindentation test results showed that the mechanical properties of the composite films were improved at low clay loading. The electrical conductivity of the films with 1.2 wt% MMT loading was increased from 3.6 to 51 S/cm, probably because of the restricted growth of PPy chains in the interspace of MMT layers.


2021 ◽  
Vol 33 (7) ◽  
pp. 1513-1518
Author(s):  
Sanoop Padinhattayil ◽  
K. Sheshappa Rai

Present study describes the analogy and comparative study of polymer nanocomposites with the known polymer matrix hydroxypropyl methylcellulose (HPMC) incorporated with graphene oxide (GO) and zinc oxide (ZnO) nanoparticles as nano fillers. The polymer nanocomposite films were carried out using solution casting method and characterized by IR spectroscopy, XRD analysis, mechanical properties, thermal characterization and optical microscopy analysis. There were several changes in the HPMC polymer by the addition of nanoparticles of GO and ZnO in structural, thermal, mechanical and optical properties. The thermal stability of the composite films increased as compared with the pure HPMC whereas the mechanical study shows a variation of down values.


Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 738 ◽  
Author(s):  
Hiroki Fujisawa ◽  
Meguya Ryu ◽  
Stefan Lundgaard ◽  
Denver P. Linklater ◽  
Elena P. Ivanova ◽  
...  

The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of nanocellulose-doped starch–polyurethane nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2 wt%. of nanocellulose were synthesised by a simple chemical process and are biodegradable. Films of a high optical transmittance T≈80% (for a 200 μm thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on (1) a resistance change and (2) micro-thermocouple detected voltage modulation caused by the heat wave, were used for the polymer films with cross sections of ∼100 μm thickness. Twice different in-plane α‖ and out-of-plane α⊥ temperature diffusivities were directly determined with high fidelity: α‖=2.12×10−7 m2/s and α⊥=1.13×10−7 m2/s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite biodegradable polymer films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this polymer nanocomposite.


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