Composite Materials
Klaudia Hurtukova; Nikola Slepičková Kasálková; Dominik Fajstavr; Anna Kutová; Petr Slepička
Abstract
In this study, we prepared hybrid materials with C and Ag layers on the surface of polydimethylsiloxane polymer (PDMS). The prepared samples were subjected to thermal treatment and modification with high energy KrF excimer laser in single shot mode. The change in the surface morphology of the samples ...
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In this study, we prepared hybrid materials with C and Ag layers on the surface of polydimethylsiloxane polymer (PDMS). The prepared samples were subjected to thermal treatment and modification with high energy KrF excimer laser in single shot mode. The change in the surface morphology of the samples was investigated by Scanning Electron Microscopy (SEM), and the chemical composition of the prepared nanocomposites was studied by Energy Dispersive Spectroscopy (EDS). Finally, the samples were tested for antibacterial activity using two bacterial strains of Gram-positive S. epidermidis and Gram-negative E.coli. Antibacterial properties were observed on the prepared samples in both bacteria colonies.
Romina P. Ollier; Matias R. Lanfranconi; Vera A. Alvarez; Leandro N. Ludue
Abstract
In this work, biodegradable nanocomposites based on polycaprolactone (PCL) reinforced with 2.5, 5.0 and 7.5 wt.% of two different clays, a commercial organo-clay (Cloisite 20A, C20A) and a laboratory modified bentonite with tributylhexadecyl phosphonium bromide (bTBHP), were prepared by melt intercalation ...
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In this work, biodegradable nanocomposites based on polycaprolactone (PCL) reinforced with 2.5, 5.0 and 7.5 wt.% of two different clays, a commercial organo-clay (Cloisite 20A, C20A) and a laboratory modified bentonite with tributylhexadecyl phosphonium bromide (bTBHP), were prepared by melt intercalation followed by compression molding. The study contemplates the analysis of chemical (Infrared Spectrometry, FTIR), morphological (X-Ray Diffractometry, XRD, Scanning Electron Microscopy, SEM, and Transmission Electron Microscopy, TEM), rheological, thermal (Differential Scanning Calorimetry, DSC, and Thermogravimetrical Analysis, TGA) and mechanical properties (tensile tests), which are important properties for packaging applications.In previous works, we concluded that higher clay dispersion degree inside the PCL matrix is expected when clays with large interlayer distance, strong hydrophobicity and strong processing stability are used. In the present work, the opposite result was obtained. Although the phosphonium treated clay (bTBHP) showed the largest interlayer distance (d001), strongest hydrophobicity and the best processing stability, the clay dispersion degree inside PCL was worse than in the case of the alkylammonium treated clay (C20A). PCL/bTBHP nanocomposites showed weaker mechanical properties in comparison with PCL/C20A ones, which is in accordance with the morphological analysis. On the other hand, the thermal properties of the matrix were not substantially affected by clay incorporation in both nanocomposites.
Rachit Ranjan; Nirmal Kumar Singh; Anand Prakash Jaiswal; Vivek Bajpai
Abstract
Aluminium matrix composite was prepared by using an innovative approach of using graphene indent on copper particles as inforcement material. The reinforcement was mixed and ball milled for 30 and 60 min respectively to get proper sight of copper fracture where graphene (GNP) can be embedded. The reinforcement ...
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Aluminium matrix composite was prepared by using an innovative approach of using graphene indent on copper particles as inforcement material. The reinforcement was mixed and ball milled for 30 and 60 min respectively to get proper sight of copper fracture where graphene (GNP) can be embedded. The reinforcement was also milled for 30 minutes to get uniform distribution of reinforcement in powder state. Casting technique was used with argon gas environment and mechanical stirrer to get final composite material. The morphological analysis has shown proper indent of graphene with Al-Cu and Cu-GNP interface. The composite so formed has micro hardness of 87 HV with an increment of 36.78% whereas yield strength and ultimate tensile strength have increased by 36.67% and 37.162% respectively.
Ritu P. Mahore; Devendra K. Burghate; Subhash B. Kondawar; Ashish P.Mahajan; Deoram V. Nandanwar
Abstract
Due to the ever growing demand of energy for various applications attention of researchers is aroused by Supercapacitors due to its superior power, energy density and cyclic life. Electrode material mainly determines the performance of Supercapacitors. Conducting polymers, metal oxides and carbon based ...
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Due to the ever growing demand of energy for various applications attention of researchers is aroused by Supercapacitors due to its superior power, energy density and cyclic life. Electrode material mainly determines the performance of Supercapacitors. Conducting polymers, metal oxides and carbon based materials are mainly used as electrode materials in Supercapacitors. Among these three categories of materials, Conducting polymers and metal oxides shows pseudo-capacitance. This paper reported the synthesis of Pure Polypyrrole (PPy) and Polypyrrole/Manganese dioxide (PPy/MnO2) nanocomposites by in-situ chemical oxidative polymerization. The synthesized materials were tested as potential candidates for the electrodes of supercapacitor. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) revealed that nanoparticles of MnO2 are well incorporated into PPy matrix. Cyclic Voltammetry (CV) indicated that PPy/MnO2 nanocomposites have an ideal capacitive behaviour and an excellent cyclibility. Electrochemical impedance spectroscopy (EIS) and Galvanostatic charge-discharge (GCD) measurements proved that nanocomposite electrode with 10% MnO2 composition showed the smallest charge transfer resistance and highest specific capacitance compared to other compositions. The electrochemical studies of PPy/MnO2 nanocomposites showed that PPy/MnO2 nanocomposites are suitable advanced materials for electrodes of the supercapacitors. Copyright © 2018 VBRI Press.
Matias R. Lanfranconi; Vera A. Alvarez;Leandro N. Ludue
Abstract
In this work, Differential Scanning Calorimetry (DSC) was used to study the crystallization behavior of nanocomposites based on polycaprolactone (PCL) reinforced with organo-montmorillonite (C20A) and organo-bentonite (B-THBP) under non-isothermal conditions. The effect of clay content (0.0, 2.5, 5.0 ...
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In this work, Differential Scanning Calorimetry (DSC) was used to study the crystallization behavior of nanocomposites based on polycaprolactone (PCL) reinforced with organo-montmorillonite (C20A) and organo-bentonite (B-THBP) under non-isothermal conditions. The effect of clay content (0.0, 2.5, 5.0 and 7.5 wt.%) was analysed. Linear and non-linear regression methods were used to calculate theoretical kinetic parameters. The study was focused on the correlation between the non-isothermal crystallization process and the morphology of the clay inside the PCL matrix. Continuous cooling transformation diagrams were obtained by means of a mathematical model that involves both induction and growth of the crystal during cooling. For the construction of these diagrams, both crystallization steps, crystals induction (analysed by the induction time equation) and growing (studied by a crystal growth model), were considered.
Larissa S. Montagna; Thaís L. do A. Montanheiro; Maurício R. Baldan; Ana Paula S. Oliveira; Marcelo A. de Farias; Marcele A. Hocevar; Luiza C. Folgueras; Fábio R. Passador; Ana Paula Lemes; Mirabel C. Rezende
Abstract
Bionanocomposites with properties similar to those of conventional polymers derived from petroleum have shown scientific and industrial interest. The current research discuss the effect of graphite nanosheets (GNS) addition on electrical, electromagnetic, and mechanical properties and also on morphological ...
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Bionanocomposites with properties similar to those of conventional polymers derived from petroleum have shown scientific and industrial interest. The current research discuss the effect of graphite nanosheets (GNS) addition on electrical, electromagnetic, and mechanical properties and also on morphological aspects of the natural polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/GNS nanocomposites and neat PHBV prepared by casting method. Nanocomposite of PHBV/1.00 wt% GNS showed good electrical conductivity values, extending the scope of application of these materials, such as in reflectors. One of the objectives of this study was to investigate the effect of different contents of GNS in neat PHBV using dynamic mechanical analysis (DMA), which showed that the addition of GNS in PHBV matrix improved the DMA properties. Transmission electron microscopy (TEM) shows good dispersion of GNS in the PHBV matrix with stacked and intercalated graphite layers and XPS confirmed the presence of carbon and oxygen in the graphite nanosheets surface.
V. M. Santhini; S.P.Suriyaraj;H. Bava Bakrudeen; M. Sugunalakshmi; S.P.Suriyaraj and H. Bava Bakrudeen
Abstract
In this study the Carvedilol drug-organo modified montmorillonite (CV/OMMT) nanocomposites were prepared using different organo modified MMT (Nanomer 1.31PS, Nanomer 1.34TCN, Nanomer 1.44P) through solution intercalation method. The degree of intercalation, microstructure and morphology of the nanocomposites ...
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In this study the Carvedilol drug-organo modified montmorillonite (CV/OMMT) nanocomposites were prepared using different organo modified MMT (Nanomer 1.31PS, Nanomer 1.34TCN, Nanomer 1.44P) through solution intercalation method. The degree of intercalation, microstructure and morphology of the nanocomposites were characterized by FTIR spectroscopy, thermogravimetric analysis and transmission electron microscopic analysis. The purpose of this study is to elaborate the drug loading capacities and drug release behaviours of different organo modified MMT (OMMT) on enhancing their swelling in aqueous medium. The in vitro drug release profiles from the CV/OMMT nanocomposites at pH 1.2 and pH 7.4 were also assessed. Simultaneously, the drug release kinetic parameters for all the CV/OMMT nanocomposites at both gastric and intestinal pH have also been discussed with established mathematical models.
Yashwant Pandit; G. T. Harini; Deepa Landage; Chetan J. Bhongale
Abstract
The formation of mesoscopic titania is done by templated mechanism in which the films are prepared by co-assembly of titania precursor species and complexing agent acetyl acetone (acac) and an amphiphilic structure-directing agent, Pluronic F127 (a triblock copolymer). Thinner films of titania having ...
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The formation of mesoscopic titania is done by templated mechanism in which the films are prepared by co-assembly of titania precursor species and complexing agent acetyl acetone (acac) and an amphiphilic structure-directing agent, Pluronic F127 (a triblock copolymer). Thinner films of titania having well organized mesoscopic structure were prepared by doctor-blading method. These films were characterized by SEM, TEM, XRD, etc. UV-Vis absorption studies showed good dye intake in very thin mesoscopic titania layers. Prototype photovoltaic device fabricated utilizing the mesoscopic titania films showed reasonable power conversion efficiency and fill factor (FF). The device with mesoscopic TiO2 layer with thickness as low as 300 nm gave solar cell efficiency 0.31% and FF of 50.2%. This proves the utility of very thin layer of mesoscopic titania fabricated by doctor-blading technique. Such a thin layer may be useful in perovskite solar cells as well. Application of versatile dye molecules, polymers with suitable anchoring functionality could lead to desired high-performance photovoltaic devices.
Vardhaman V. Khedekar; Shaikh Mohammed Zaeem; Santanu Das
Abstract
Graphene-Metal oxide nanocomposites have been extensively investigated due to their potential applications in the fields of energy devices, including, solar cells, fuel cells, batteries, sensors, electro-catalysis, and photo-catalysis. Among them, several researches have been performed on supercapacitors, ...
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Graphene-Metal oxide nanocomposites have been extensively investigated due to their potential applications in the fields of energy devices, including, solar cells, fuel cells, batteries, sensors, electro-catalysis, and photo-catalysis. Among them, several researches have been performed on supercapacitors, which could be best used with devices that require high current for short duration of time. Here, in this article, we present a brief review on the recent advances on the graphene-metal oxide nanocomposites for supercapacitor technologies and the future perspective of this field of research. A wide range of graphene-metal oxide synthesis techniques have been discussed with a focus on the advancement of nanocomposites with controlled features, including, particle size, morphologies, surface structures, pore size, pore-distributions, etc. Specifically, various nanocomposites and their role in supercapacitor electrodes are discussed with their explicit electrochemical charge-storage mechanisms along with charge-transfer techniques. Furthermore, this analysis demonstrates current trends and future directions in research on graphene-metal oxide nanocomposite electrodes for the performance enhancement in next-generation supercapacitor devices.
Dafang He; Lixian Li; Fengjuan Bai; Chenyang Zha; Liming Shen; Harold H. Kung; Ningzhong Bao
Abstract
A unique hierarchically nanostructured composite of Si nanoparticles (Si NPs) embedded in a three-dimensional (3D) carbon nanotube (CNT)/graphene sheet (GS) matrix (Si@CNT/GS) is fabricated by freeze-drying and thermal reduction. In this novel nanostructured composite, since the intertwined elastic CNTs ...
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A unique hierarchically nanostructured composite of Si nanoparticles (Si NPs) embedded in a three-dimensional (3D) carbon nanotube (CNT)/graphene sheet (GS) matrix (Si@CNT/GS) is fabricated by freeze-drying and thermal reduction. In this novel nanostructured composite, since the intertwined elastic CNTs effectively disperse the Si NP anode material and provide extra physical connections between Si NPs and the surrounding 3D conductive matrix, the interconnected 3D CNT/GS matrix can serve to buffer the volume change of the Si NPs during cycling while simultaneously enhance the electrical conductivity of the overall electrode. As a result, Si@CNT/GS nanocomposite exhibits a high reversible capacity of 1362 mAh·g -1 at 500 mA·g -1 over 500 cycles, and an excellent rate capability of 504 mAh·g -1 at 8400 mA·g -1 , considerably improving the battery performance compared with those electrodes made from Si@graphene nanocomposites, thus exhibiting great potential as an anode composite structure for lithium storage. Copyright © 2017 VBRI Press.
K. Hareesh; R. P. Joshi; V. N. Bhoraskar; S. D. Dhole
Abstract
Gold-reduced graphene oxide (AG) nanocomposites were synthesized by one-step gamma radiation assisted method. UV-Visible spectroscopic results showed the disappearance of 230 nm peak and appearance of a peak around 269 nm in AG nanocomposite confirming the reduction of GO, and also a peak around 534 ...
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Gold-reduced graphene oxide (AG) nanocomposites were synthesized by one-step gamma radiation assisted method. UV-Visible spectroscopic results showed the disappearance of 230 nm peak and appearance of a peak around 269 nm in AG nanocomposite confirming the reduction of GO, and also a peak around 534 nm appears confirming the formation of gold nanoparticles (AuNPs). X-ray diffractogram results of AG nanocomposite showed a broad peak around 25° corresponding to reduced graphene oxide and also it showed peak corresponding to face centered cubic structured AuNPs corroborating the UV-Visible spectroscopic results. The decoration of AuNPs of size 6 nm on reduced graphene oxide sheet was revealed by transmission electron microscopic results. X-ray photoelectron spectroscopic results confirmed the removal of oxygen functional groups from graphene oxide and formation of Au 4f in AG nanocomposite. The synthesized AG nanocomposite showed enhanced catalytic reduction of 4-Nitrophenol compared to rGO and AuNPs due to synergistic effect of individual component. Gamma radiation assisted method synthesis of Au-rGO nanocomposite may emerge as one-step synthesis that don’t require high temperature or harsh reducing agent.
Harish Mudila; Sweta Rana; Mohammad G. H. Zaidi
Abstract
A series of Polyindole/Graphene nanocomposites (PGNCs) as electrochemical energy storage materials were fabricated at varying concentration (%, w/w) of graphene raging 3.0–9.0 in Polyindole (PIN) matrix in Supercritical CO2. The electrochemical behavior of PGNC prepared at different proportion ...
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A series of Polyindole/Graphene nanocomposites (PGNCs) as electrochemical energy storage materials were fabricated at varying concentration (%, w/w) of graphene raging 3.0–9.0 in Polyindole (PIN) matrix in Supercritical CO2. The electrochemical behavior of PGNC prepared at different proportion of graphene was investigated. The PGNC@9% has rendered specific capacitance of 389.17 F/g, along with energy and power densities of 13.51 Wh/kg and 511.95 W/kg respectively, which is greater as compared to graphene prepared through thermal reduction of graphene oxide. However, PIN comprises low capacitance of 24.48 F/g. Successive scans of PGNCs electrode for 1000 cycles at the scan rate of 0.1 V/s in KOH (1.0 M) shows a capacitive retention of ~98.6% indicating the electrochemical stability of the electrodes, with successive charge-discharge behavior. PGNCs display all the major peaks in Fourier Transform-Infrared and X-Ray diffraction spectra. Scanning electron micrograph in permutation with XRD spectra indicates the exfoliation of graphene into the matrix of PIN. Simultaneous TG-DSC reveals increased thermal stability of PGNCs with fractions of graphene. The good capacitive and charge-discharge performance indicates that supercritically fabricated PGNCs may serve as potential electrode materials for electrochemical energy storage devices.
Issam Derkaoui; Mohammed Khenfouch; Ibrahim Elmokri; Bakang M. Mothudi; Mokhotjwa S. Dhlamini; Sabata J. Moloi. Anouar Jorio; Izeddine Zorkani; Malik Maaza
Abstract
Most recently, Vanadium oxide nanoparticles/reduced Graphene oxide (VO-NPs/rGO) nanocomposite have attracted extensive attention due to their potential applications in energy-related areas. Hence, understanding the interactions on behalf the effect of graphene layers on the modification of VO-NPs properties ...
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Most recently, Vanadium oxide nanoparticles/reduced Graphene oxide (VO-NPs/rGO) nanocomposite have attracted extensive attention due to their potential applications in energy-related areas. Hence, understanding the interactions on behalf the effect of graphene layers on the modification of VO-NPs properties as well as their growth mechanism are of great importance. In this work, our results are revealing that VO-NPs were efficiently grown and coated on the graphene surface and are clearly showing the strong effect of rGO layers on the growth of VO-NPs which leads to a modification in the form, the shape and also the phase. These interactions which were studied based on structural and morphological investigations will play an important role on the modification of these nanocomposites properties which is suitable for a wide range of potential applications and particularly as electrode in Li-ion batteries.
Jyoti Srivastava; Pawan Kumar Khanna; Priyesh V More; Neha Singh
Abstract
Silver/Polypyrrole/Polyvinylalcohol polymer nanocomposite films were prepared by in-situ polymerization of pyrrole with variable loading of silver nanoparticles from 0.5-10%. The conducting films prepared from the nanocomposite solution were flexible, light weight, thermally stable and showed high ...
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Silver/Polypyrrole/Polyvinylalcohol polymer nanocomposite films were prepared by in-situ polymerization of pyrrole with variable loading of silver nanoparticles from 0.5-10%. The conducting films prepared from the nanocomposite solution were flexible, light weight, thermally stable and showed high hydrophobicity/hydrophilicity ratio. X-Ray diffraction measurement showed formation of fcc silver nanoparticles with particle size in the range of about 20-40 nm. UV-visible spectroscopy revealed the characteristic bands of Ag nanoparticles and polypyrrole in the so obtained co-polymer nanocomposites. The SEM studies of the nanocomposite films showed that the filler material was well conjugated in the Polymer matrix. Vector Network Analyser showed Electromagnetic shielding efficiency (EMI) efficiency as high as -35 dB in the X band (8-12GHz).
Jimena S. Gonzalez; Alejandra Ponce; Vera A. Alvarez
Abstract
During the last decade researchers have been working to find effective wound dressing materials. The materials have to be designed to hold moisture in the surface of the wound, providing the ideal environment for cleaning the wound, absorbing the exudates, eliminating the odour and promoting the healing ...
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During the last decade researchers have been working to find effective wound dressing materials. The materials have to be designed to hold moisture in the surface of the wound, providing the ideal environment for cleaning the wound, absorbing the exudates, eliminating the odour and promoting the healing process. In this scenario, hydrogels emerge as excellent options for that. However, due to poor mechanical and antimicrobial properties of many conventional hydrogels, composite hydrogels are now designed in order to improve mechanical stiffness and durability. For this purpose, nanocomposite based on poly(vinyl alcohol) (PVOH) and different concentration of bentonite (0-7 wt.%) were obtained by the freezing-thawing technique and characterized by means of morphological, physical, thermal, mechanical, barrier and antimicrobial properties. Herein it was developed a non-expensive, eco-friendly and a facile method to obtain nanocomposite hydrogels based on PVOH with reasonable mechanical properties (Young Modulus of 0.5-0.8 MPa), good microbial barrier properties, adequate water vapour transmission rates and excellent swelling behaviour (195-336%). Moreover, it was found that the porous sizes of the samples can be controlled by the addition of the clay. All obtained results indicate that the PVOH/ 3% bentonite hydrogels show potential to be used as wound healing.
Milind D. Deshpande; Subhash B. Kondawar
Abstract
In this paper, we report the influence of functionalized multi-walled carbon nanotubes (MWCNTs) on transport properties of conducting polymers polythiophene (PTH) and polyaniline (PANI). Nanocomposites based on multi-walled carbon nanotubes were synthesized by in-situ oxidative polymerization of thiophene/aniline ...
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In this paper, we report the influence of functionalized multi-walled carbon nanotubes (MWCNTs) on transport properties of conducting polymers polythiophene (PTH) and polyaniline (PANI). Nanocomposites based on multi-walled carbon nanotubes were synthesized by in-situ oxidative polymerization of thiophene/aniline monomer in the presence of functionalized MWCNTs. These nanocomposites have been characterized by SEM, UV-VIS, FTIR, and XRD to study the effect of incorporation of MWCNTs on the morphology, structure and crystalline of the conducting polymers. Nanocomposites have shown high electrical conductivity compared to that of pure PTH/PANI. The enhancement in conductivity of the nanocomposites is due to the charge transfer effect from the quinoid rings of the PTH/PANI to the MWCNT. The effect of MWCNT on the transport properties of PTH and PANI was systematically studied and compared in terms of transport parameters. Charge localization length and most probable hopping distance were found to be decreased with wt % of CNT, whereas the charge hopping energy was found to be increased in nanocomposites. The improved transport properties of both the types of nanocomposites due to incorporation of CNT in conducting polymer matrix can be utilized for solar cells, capacitors, electronic devices as well as chemical sensors.
C. Stella; N. Soundararajan; K. Ramachandran
Abstract
Chunk shaped ZnO/Co3O4 nanocomposites for different concentrations of 90:10 (Z9C1), 70:30 (Z7C3), and 50:50 (Z5C5) were successfully synthesized by co-precipitation method. The structure, morphology, and elemental composition of the prepared samples were characterized by X-ray diffraction (XRD), scanning ...
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Chunk shaped ZnO/Co3O4 nanocomposites for different concentrations of 90:10 (Z9C1), 70:30 (Z7C3), and 50:50 (Z5C5) were successfully synthesized by co-precipitation method. The structure, morphology, and elemental composition of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS), respectively which confirm the formation of ZnO/Co3O4nanocomposites. Raman analysis confirmed the presence of oxygen vacancies in the Z5C5 sample. The magnetic studies revealed that, the Z5C5 nanocomposite exhibit room temperature ferromagnetism. The gas sensing property clearly confirm the response of Z5C5 sensor which was as high as 5.6%, about 4 times higher than Z9C1 sample. The enhancement of gas sensing property is due to the collective contribution of smaller particle size, oxygen vacancies, and the formation of more p-n hetero junction in Z5C5 nanocomposite.
Moises Oviedo Mendoza; Edna M. Valenzuela-Acosta; Evgen Prokhorov; Gabriel Luna-Barcenas; Siva Kumar-Krishnan
Abstract
In this work, we report the relationship between the electrical conductivity and nanoparticle effective surface area with functional properties of polymer-metal and polymer-clay nanocomposites. Conductivity of the nanocomposite strongly depends upon metal/clay nanoparticle size and concentration that ...
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In this work, we report the relationship between the electrical conductivity and nanoparticle effective surface area with functional properties of polymer-metal and polymer-clay nanocomposites. Conductivity of the nanocomposite strongly depends upon metal/clay nanoparticle size and concentration that ultimately dictate where the system percolates. Knowledge of percolation properties allows the design of functional nanocomposites for biomedical and sensors applications. Herein we report the successful production of three functional chitosan-metal/clay nanocomposites: a) chitosan-Ag films with antibacterial properties, b) chitosan-Au potentiometric sensor for detection of Cu ++ and c) chitosan-nanoclay potentiometric sensor for detection of NO3-. For all these applications the best functional performance of nanocomposites has been observed when NPs concentration increases and approaches the percolation threshold. The obtained relationship between electrical percolation threshold and functional properties of polymer nanocomposites is of primary importance in the design of high-performance applications.
A. Jayakumar; N. Malarvizhi; B. Rajeswari; A. Murali; Debasis Samanta; P. Saravanan; C. Muralidharan; Sellamuthu N. Jaisankar
Abstract
Semi-interpenetrating polymer networks (semi-IPNs) based polyurethane (PU), polyvinyl alcohol (PVA) and functionalized single–walled carbon nanotubes (f-SWCNTs), films were prepared using sequential polymerization technique. Carboxyl functionalized SWCNTs in semi-IPNs matrixes were confirmed by ...
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Semi-interpenetrating polymer networks (semi-IPNs) based polyurethane (PU), polyvinyl alcohol (PVA) and functionalized single–walled carbon nanotubes (f-SWCNTs), films were prepared using sequential polymerization technique. Carboxyl functionalized SWCNTs in semi-IPNs matrixes were confirmed by Raman spectroscopy and hydrogen bond interactions were studied using attenuated total reflectance fourier transform infrared spectroscopy. The soft segments of the PU with nanotubes interact much stronger than hard segments, this was observed by Differential Scanning Calorimeter. The activation energy and thermal degradation temperatures were calculated from thermogravimetric analysis. The tensile strength and Young’s modulus was increases with increase f-SWCNTs loadings. The AFM micrographs clearly shows f-SWCNTs were located in semi-IPNs matrix. Further, SWCNTs are attached in PU and spherical structures were dispersed in polymer matrix. The surface activation energy of the composites were increases up to 29 kJ/mole with increasing SWCNTs content on PU networks.
Sonika Thakur; Anupinder Singh; Lakhwant Singh
Abstract
Self-standing polyaniline (Pani) films modified with gold nanoparticles (Au NP’s), where Au NP’s are added in different successive weight percents, have been synthesized by conventional chemical polymerization technique. An in-depth investigation of the structural and electrical characteristics ...
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Self-standing polyaniline (Pani) films modified with gold nanoparticles (Au NP’s), where Au NP’s are added in different successive weight percents, have been synthesized by conventional chemical polymerization technique. An in-depth investigation of the structural and electrical characteristics of prepared films has been conducted using various characterizations. The X-ray diffraction (XRD) validates the presence of Au NP’s in Pani and the results are supported well by energy dispersive X-ray analyzer (EDX). The field emission scanning electron microscopy (FESEM) clearly shows thorough dispersion of Au NP’s in the amorphous host matrix with minor aggregation. The Fourier transform infrared red (FTIR) studies give the information of possible chemical interaction between the nanoparticles and polymer which is in good agreement with charge transfer mechanism proposed in the manuscript. The temperature dependent dc electrical conductivity has been observed to depend strongly on the nanoparticle loading and follows Mott’s three-dimensional variable range hopping (3D VRH) conduction mechanism. Parameters obtained from Hall Effect measurements are of same order as is calculated by dc measurements which indicates a very good corroboration of results. Higher ac conductivity, dielectric constant and dielectric loss of nanocomposites have also been observed as compared to that of pure Pani.
Annu Sharma; Jyoti Rozra; Isha Saini
Abstract
In the present work, effects of annealing temperature on structural and optical properties of silver-glass nanocomposites synthesized by the combined use of ion-exchange and subsequent thermal annealing in air have been investigated using Transmission electron microscopy (TEM), UV–Visible absorption ...
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In the present work, effects of annealing temperature on structural and optical properties of silver-glass nanocomposites synthesized by the combined use of ion-exchange and subsequent thermal annealing in air have been investigated using Transmission electron microscopy (TEM), UV–Visible absorption spectroscopy and Photoluminescence spectroscopy. The appearance of SPR peak characteristic of silver nanoparticle formation around 429 nm in absorption spectra of silver-glass nanocomposite samples indicates towards the formation of silver nanoparticles in glass. The size of silver nanoparticles has been found to increase with increase in annealing temperature. At an annealing temperature of 200°C the size of silver nanoparticles comes out to be 2.31 nm which increases to a value of 7.60 nm at an annealing temperature of 550°C. TEM investigation indicates that silver nanoparticles of size 6.57+1.14 nm are formed in glass matrix. UV-visible absorption and reflection data has been analyzed to ascertain optical properties such as absorption coefficient (α), refractive index (n) and dielectric constant (ε). Emissions bands in the photoluminescence spectra were analyzed to investigate different oxidation states of silver present in the prepared nanocomposite samples. Formation of Ago atoms from Ag + ions are responsible for the quenching of photoluminescence intensity at higher temperature. Such nanocomposites are expected to be promising materials for ultrafast optical switches and for sensing applications.
Subhash B. Kondawar; Arti I. Nandapure; Bharti I. Nandapure
Abstract
Nanocrystalline nickel ferrite (NiFe2O4) powder of crystallite size ~20 nm was synthesized by refluxing method. Electrically conductive polyaniline-nickel ferrite (PANI/NiFe2O4) nanocomposites have been synthesized by an in-situ polymerization of aniline monomer in the presence of as-prepared NiFe2O4 ...
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Nanocrystalline nickel ferrite (NiFe2O4) powder of crystallite size ~20 nm was synthesized by refluxing method. Electrically conductive polyaniline-nickel ferrite (PANI/NiFe2O4) nanocomposites have been synthesized by an in-situ polymerization of aniline monomer in the presence of as-prepared NiFe2O4 in different weight percentage (5%, 10%, and 15%). These nanocomposites were subsequently characterized for morphological, crystalline, structural, electrical and magnetic properties by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Four Probe Resistivity (FPR) and Vibrating Sample Magnetometer (VSM). Existence of NiFe2O4 in the nanocomposites was confirmed by XRD, FTIR and TEM analysis. The change in morphology with crystallite size ? 50 nm was observed for the nanocomposites clearly indicate the coating of PANI on NiFe2O4 . Nanocomposites showed increase in saturation magnetization as compared to that of PANI and increase in electrical conductivity as compared to that of NiFe2O4 indicating the synergistic effect of individual components. The saturation magnetization drastically increased as nickel ferrite content changed from 5 to 15% in nanocomposites. The conductivity of nanocomposites increased with temperature, exhibiting typical semiconductor behavior. The nanocomposites show semiconducting and ferromagnetic behaviour. The electrical conductivity of nanocomposites decreased from 1.089 to 0.268 S/cm, but saturation magnetization increased from 0.97 to 2.803 emu/g, when ferrite content changed from 5 to 15 wt%, indicates such nanocomposites are good for electromagnetic devices.
B. N. Patil; S. A. Acharya
Abstract
In the present work, ZnS-Gaphene (ZnS-GNS) composite was prepared by microwave irradiation method. The prepared samples were characterized by X-ray diffraction (XRD), to confirm the formation of GNS by reducing Graphite as well as ZnS-GNS nanocomposite. Raman spectroscopy identified D and G photon vibration ...
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In the present work, ZnS-Gaphene (ZnS-GNS) composite was prepared by microwave irradiation method. The prepared samples were characterized by X-ray diffraction (XRD), to confirm the formation of GNS by reducing Graphite as well as ZnS-GNS nanocomposite. Raman spectroscopy identified D and G photon vibration mode of GNS in the ZnS-GNS composite. X-ray photoelectrons spectra are also detected presence of graphene in ZnS. UV/VIS Spectra are studied for evaluation of photocatalytic activity. The composite is explored as photocatalysts to study dye degradation using methylene blue dye in aqueous slurry under irradiation of 663 nm wavelength. Under the same conditions the photocatalytic activity of the pure ZnS is also examined. The ZnS-GNS composite is found in enhancing the rate of photodegradation of toxic dyes as compared to pure ZnS. This Graphene based metal sulphide/oxide semiconductor nanocomposites are high potential material for Photo-degradation of toxic dyes, and act as good photocatalyst.
M. N. Muralidharan;Seema Ansari
Abstract
Optically triggered actuators offer unique advantages like wireless actuation and remote control when comared to other type of actuators. They are extremely useful where stimulus other than electricity or heat is preferred. Thermally reduced graphene oxide (TRGO)/thermoplastic polyurethane (TPU) composite ...
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Optically triggered actuators offer unique advantages like wireless actuation and remote control when comared to other type of actuators. They are extremely useful where stimulus other than electricity or heat is preferred. Thermally reduced graphene oxide (TRGO)/thermoplastic polyurethane (TPU) composite actuators were prepared by simple solution casting technique. The photomechanical actuation properties of the composites were studied under infrared illumination. It was found that the photomechanical response can be tuned by controlling the applied prestrain and the filler loading. Even with a low filler loading of 2 wt. % TRGO, the composite exhibited a very high photomechanical strain of 50.2% with an excellent stress of 1680 kPa at a prestrain of 220%. These high values were achieved at a very low light intensity of 16mWcm -2 . The high values of strain obtained with very good generative forces indicate that this is a promising material for light triggered actuators for many potential applications including robotics and biomedical devices.
Anupama Chaturvedi; Ashutosh Tiwari; Atul Tiwari
Abstract
This communication describes the development of graphene and graphene reinforced polyvinylester nanocomposites. Low concentration of graphene was incorporated in the polymer matrix with the help of two different solvents. The role of solvent in the nanocomposite was studied. The FTIR spectroscopy and ...
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This communication describes the development of graphene and graphene reinforced polyvinylester nanocomposites. Low concentration of graphene was incorporated in the polymer matrix with the help of two different solvents. The role of solvent in the nanocomposite was studied. The FTIR spectroscopy and electron microscopy have supported the presence of graphene in the nanocomposites. It was discovered that vehicular medium (i.e., solvent) plays a vital role in the properties of the ultimate nanocomposites. When dimethylacetamide was used as solvent, the morphological analysis suggested the increased toughness while in case when tetrahydrofuran was used as solvent, nanocomposite appeared brittle in nature.
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