Graphene-reinforced polymer nanocomposites are under intense investigation in recent years. In this work, graphene nanosheets have been prepared using chemical reduction method of graphene oxide. Graphene-reinforced epoxy nanocomposites show an enhancement in mechanical and thermal properties at 0.05 wt.% of graphene in epoxy matrix. Modification of graphene with polyvinylpyrrolidone (PVP) shows the significant enhancement in mechanical and thermal properties of epoxy nanocomposites. PVP-modified graphene nanosheets reduces the gap of enthalpic and entropic penalties and facilitates improved dispersion of graphene in epoxy matrix. In addition, enhanced dispersion of PVP-modified graphene in epoxy matrix results in better load transfer across graphene-epoxy interface. Glass transition temperature (Tg) of PVP-modified graphene epoxy nanocomposites increases as compared to pure epoxy because there exist an interaction between epoxy and PVP. Fractography study reveals the localized ductile fracture. © 2016 Taylor &amp; Francis.

Soumen Pal

Department of Manufacturing Engineering

School of Mechanical Engineering

Vellore Campus

Saha M

Tambe P

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Thermodynamic approach to enhance the dispersion of graphene in epoxy matrix and its effect on mechanical and thermal properties of epoxy nanocomposites

Composite Interfaces

In this investigation, the mechanical properties such as compression, impact, and flexural properties of graphene decorated with graphene quantum dots (GDGQD) epoxy composites with concentration of GDGQD ranging from 0.25 to 1 wt % were studied. Ideal mechanical properties are obtained by systematically varying the filler weight in the epoxy matrix. The morphological studies of GDGQD have been characterized using transmission electron microscope, X-ray diffraction, and Fourier transform infrared technique. The compression, impact, and flexural strengths were enhanced effectively by the GDGQD loading. With the addition of 0.75 wt % of GDGQD, the compressive strength, compressive modulus, flexural strength, and flexural modulus of the composites were improved by 22, 29, 31, and 63%, respectively. Also an improvement in impact strength of 102% for 0.75 wt % GDGQD epoxy sample was also obtained. Examination of fractured test specimens was performed with scanning electron microscope. The enhancement in the mechanical properties is due to the better stress transfer that is attributed by enhanced interfacial bonding between GDGQDs and the epoxy. Using the GDGQD aspect ratio in the two-dimensional randomly oriented filler modified Halpin–Tsai model, the theoretical flexural modulus for the GDGQD/epoxy composites has been established. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48680. © 2019 Wiley Periodicals, Inc.

Journal of Applied Polymer Science

Investigation of mechanical properties of graphene decorated with graphene quantum dot‐reinforced epoxy nanocomposite

In this paper, the thermal conductivity, dielectric properties and dynamic mechanical properties were studied for Graphene Decorated with Graphene Quantum Dots (GDGQD)-epoxy nanocomposites. A maximum thermal conductivity enhancement of 19% registered for 0.75 wt% GDGQD sample where a low acoustic impedance mismatch between the interface of GDGQD fillers and the epoxy matrix occur and a dielectric constant increase of 6% due to the better charge accumulation at the conductive filler/ insulating polymer interface of the composite. Further DMA is performed using the cantilever mode. The loss modulus peak obtained for 0.75 wt% GDGQD-epoxy sample given a maximum value due to the interface interaction and the corresponding storage modulus shown a maximum increment of 21%, due to the molecular dynamics and cross-linking density of the epoxy matrix with GDGQD. The thermal stability of the samples evaluated using Thermal Gravimetric Analysis (TGA) shown an improvement in glass transition temperature (Tg) of nanocomposite for 0.75 wt% GDGQD by 11 °C where a greater dispersion of the fillers and efficient functional groups interaction are responsible factors. © 2019 IOP Publishing Ltd.

Materials Research Express

Study on the thermal, dielectric, and dynamic mechanical properties of graphene decorated with graphene quantum dots (GDGQD) reinforced epoxy nanocomposites

Influence of covalent and non-covalent modification of graphene on the mechanical, thermal and electrical properties of epoxy/graphene nanocomposites: a review

In this work, the combination of graphene decorated with graphene quantum dots (G-D-GQDs) and barium titanate (BaTiO3) nanoparticles filled poly (vinyledene fluoride) (PVDF) nanocomposites are prepared using solvent casting method. The modification of G-D-GQDs and BaTiO3 nanoparticles with polyvinyl pyrrolidone (PVP) show finer dispersion in PVDF matrix as compared to unmodified G-D-GQDs and BaTiO3 nanoparticles in PVDF matrix. XRD of PVDF nanocomposites shows the formation of α and β form of PVDF crystals. The incorporation of the combination of PVP modified BaTiO3 nanoparticles and G-D-GQDs in PVDF matrix show a decrease in crystallization temperature (Tc), percent crystallinity (Xc) and increase in thermal stability as compared to unmodified PVDF/BaTiO3/G-D-GQDs nanocomposites, due to interaction of PVP modified nanoparticles with PVDF. Further, the incorporation of the combination of 20 wt.% BaTiO3 nanoparticles and 3 wt.% G-D-GQDs in PVDF matrix show a giant dielectric constant. The giant dielectric constant is achieved due to accumulation of more charges across conductor-insulator interface, more numbers of microcapacitor formed and enhanced interfacial compatibility between BaTiO3/G-D-GQDs with PVDF through PVP. The loss tangent (tan δ) of PVP modified G-D-GQDs and BaTiO3 nanoparticles and its PVDF nanocomposites is low due to lower leakage current, which make the material suitable for various applications. © 2017 Informa UK Limited, trading as Taylor &amp; Francis Group.

Giant permittivity of three phase polymer nanocomposites obtained by modifying hybrid nanofillers with polyvinylpyrrolidone

EMI shielding effectiveness of graphene decorated with graphene quantum dots and silver nanoparticles reinforced PVDF nanocomposites

Hexagonal boron nitride (hBN) nanoplatelets have attracted considerable interest recently. In this work, hBN nanoplatelets have been prepared using chemical exfoliation route. The exfoliation of hBN nanoplatelets takes place along the (0 0 2) plane without destroying the crystal structure. The hBN nanoplatelets are modified using polyvinylpyrrolidone (PVP), a non-ionic surfactant in order to achieve finer dispersion of hBN nanoplatelets in ethyl alcohol, and subsequently in the epoxy matrix. The enhanced dispersion of hBN nanoplatelets achieved using PVP is due to the adsorption of PVP over the hBN nanoplatelets, and PVP miscibility with epoxy resin in an uncured state. Due to the finer dispersion of hBN nanoplatelets in the epoxy matrix, the flexural properties are higher as compared to pure epoxy. PVP assisted dispersed hBN nanoplatelets reinforced with epoxy nanocomposites have higher flexural properties as compared to pure hBN nanoplatelets-reinforced epoxy nanocomposites. The enhanced dispersion of hBN nanoplatelets using PVA also limits the decrease in glass transition temperature (Tg). Further, thermal stability of the epoxy increase with an addition of PVP modified and unmodified hBN nanoplatelets in the epoxy matrix as compared to pure epoxy. Fractography studies reveal that addition of PVP modified and unmodified hBN nanoplatelets in the epoxy matrix depict rough surface with many small facets due to resistance offered by the dispersed nanoplatelets. © 2015 Taylor &amp; Francis.

Effect of non-ionic surfactant assisted modification of hexagonal boron nitride nanoplatelets on the mechanical and thermal properties of epoxy nanocomposites

Effect of sodium alginate modification of graphene (by ‘anion-π’ type of interaction) on the mechanical and thermal properties of polyvinyl alcohol (PVA) nanocomposites

The influence of melt-mixing parameters on the development of "network-like" structure of multiwall carbon nanotubes (MWNTs) in injection-molded polypropylene (PP)/MWNTs composites was assessed through AC electrical conductivity measurements. A higher melt-mixing temperature (260°C as compared to 200, 220, and 240°C) at a fixed rotational speed of the screws (150 rpm) and at a fixed mixing time (15 min) has yielded maximum improvement in electrical conductivity in PP/MWNTs composites of 3 wt % MWNTs content. Next to higher melt-mixing temperature, a variation in the melt-mixing time has also led to a variation in electrical conductivity of the composites. Raman spectroscopic analysis revealed an increase in the ratio of intensity due to G-band over that of D-band (I G/I D) of the MWNTs in the "skin" region as compared to the "core" region of the injection-molded composites irrespective of the melt-mixing conditions. Microscopic observations could not provide much insight into the variation of MWNTs network-like structure in various PP/MWNTs composites. An attempt has been made to understand the variation of network-like structure of MWNTs in PP/MWNTs composites as a function of melt-mixing parameters through electrical conductivity measurements, Raman spectroscopic analysis, and morphological investigations. Copyright © 2012 Wiley Periodicals, Inc.

The influence of melt-mixing process conditions on electrical conductivity of polypropylene/multiwall carbon nanotubes composites

An innovative strategy for the production of novel magnetite poly(vinyl alcohol) nanocomposite films with double-capped synthesized Fe3O4nanoparticles with citric acid and vitamin C

Journal	Composite Interfaces
Publisher	Informa UK Limited
ISSN	0927-6440
Open Access	0