Search query: Polypropylene/ graphene oxide nanocomposites

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abstract: Writing Conductive Lines with Hot Tips The interface within devices between conductors, semiconductors, and insulators is usually created by stacking patterned layers of different materials. For flexible electronics, it can be advantageous to avoid this architectural constraint. Graphene oxide, formed by chemical exfoliation of graphite, can be reduced to a more conductive form using chemical reductants. Wei et al. (p. 1373) now show that layers of graphene oxide can also be reduced using a hot atomic force microscope tip to create materials comparable to those of organic conductors. This process can create patterned regions (down to 12 nanometers in width) that differ in conductivity by up to four orders of magnitude. Conducting regions can be drawn on graphene oxide sheets with a heated atomic force microscope tip. The reduced form of graphene oxide (GO) is an attractive alternative to graphene for producing large scale flexible conductors and for creating devices that require an electronic gap. We report on a means to tune the topographical and electrical properties of reduced GO (rGO) with nanoscopic resolution by local thermal reduction of GO with a heated atomic force microscope tip. The rGO regions are up to four orders of magnitude more conductive than pristine GO. No sign of tip wear or sample tearing was observed. Variably conductive nanoribbons with dimensions down to 12 nanometers could be produced in oxidized epitaxial graphene films in a single step that is clean, rapid, and reliable.
author_names: Zhongqing Wei

Debing Wang

Suenne Kim

Soo-Young Kim

Michael K Yakes

Arnaldo R Laracuente

Zhenting Dai

Seth R Marder

Claire Berger

William P King

Walt A de Heer

Paul E Sheehan

Elisa Riedo
title: Nanoscale Tunable Reduction of Graphene Oxide for Graphene Electronics
venue: Science
year: 2010

abstract: The thermal and flammability properties of polypropylene/multi walled carbon nanotube, (PP/MWNT) nanocomposites were measured with the MWNT content varied from 0.5 to 4% by mass. Dispersion of MWNTs in these nanocomposites was characterized by SEM and optical microscopy. Flammability properties were measured with a cone calorimeter in air and a gasification device in a nitrogen atmosphere. A significant reduction in the peak heat release rate was observed; the greatest reduction was obtained with a MWNT content of 1% by mass. Since the addition of carbon black powder to PP did not reduce the heat release rate as much as with the PP/MWNT nanocomposites, the size and shape of carbon particles appear to be important for effectively reducing the flammability of PP. The radiative ignition delay time of a nanocomposite having less than 2% by mass of MWNT was shorter than that of PP due to an increase in the radiation in depth absorption coefficient by the addition of carbon nanotubes. The effects of residual iron particles and of defects in the MWNTs on the heat release rate of the nanocomposite were not significant. The flame retardant performance was achieved through the formation of a relatively uniform network structured floccule layer covering the entire sample surface without any cracks or gaps. This layer re emitted much of the incident radiation back into the gas phase from its hot surface and thus reduced the transmitted flux to the receding PP layers below it, slowing the PP pyrolysis rate. To gain insight into this phenomena, thermal conductivities of the nanocomposites were measured as a function of temperature while the thermal conductivity of the nanocomposite increases with an increase in MWNT content, the effect being particularly large above 160 degC, this increase is not as dramatic as the increase in electrical conductivity, however.
author_names: Takashi Kashiwagi

Eric A Grulke

Jenny Hilding

Katrina M Groth

Richard H Harris

Kathryn M Butler

John R Shields

Seman B Kharchenko

Jack F Douglas
title: Thermal and flammability properties of polypropylene/carbon nanotube nanocomposites
year: 2004

abstract: Abstract In the large field of nanotechnology, polymer matrix based nanocomposites have become a prominent area of current research and development. Exfoliated clay based nanocomposites have dominated the polymer literature but there are a large number of other significant areas of current and emerging interest. This review will detail the technology involved with exfoliated clay based nanocomposites and also include other important areas including barrier properties, flammability resistance, biomedical applications, electrical/electronic/optoelectronic applications and fuel cell interests. The important question of the "nano effect" of nanoparticle or fiber inclusion relative to their larger scale counterparts is addressed relative to crystallization and glass transition behavior. Of course, other polymer (and composite) based properties derive benefits from nanoscale filler or fiber addition and these are addressed.
author_names: Donald R Paul

Lloyd Mahlon Robeson
title: Polymer nanotechnology: Nanocomposites
year: 2008

abstract: It is demonstrated from stress induced Raman bands shifts that stress can be transferred from a polymer matrix to a graphene monolayer (see image) in a model nanocomposite. It is shown further that the behavior can be modeled using continuum mechanics and that the interface between the graphene and the polymer breaks down at a shear stress of the order of 2 MPa.
author_names: Lei Gong

Ian A Kinloch

Robert J Young

Ibtsam Riaz

Rashid Jalil

Kostya S Novoselov
title: Interfacial stress transfer in a graphene monolayer nanocomposite.
venue: Advanced materials
year: 2010

abstract: Graphene sheets one atom thick two dimensional layers of sp2 bonded carbon are predicted to have a range of unusual properties. Their thermal conductivity and mechanical stiffness may rival the remarkable in plane values for graphite ~3,000 W m 1 K 1 and 1,060 GPa, respectively) their fracture strength should be comparable to that of carbon nanotubes for similar types of defects; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties. One possible route to harnessing these properties for applications would be to incorporate graphene sheets in a composite material. The manufacturing of such composites requires not only that graphene sheets be produced on a sufficient scale but that they also be incorporated, and homogeneously distributed, into various matrices. Graphite, inexpensive and available in large quantity, unfortunately does not readily exfoliate to yield individual graphene sheets. Here we present a general approach for the preparation of graphene polymer composites via complete exfoliation of graphite and molecular level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene graphene composite formed by this route exhibits a percolation threshold of ~0.1 volume per cent for room temperature electrical conductivity, the lowest reported value for any carbon based composite except for those involving carbon nanotubes; at only 1 volume per cent, this composite has a conductivity of ~0.1 S m 1, sufficient for many electrical applications. Our bottom up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene based materials and their use in a variety of applications.
author_names: Sasha Z Stankovich

Dmitriy A Dikin

Geoffrey H B Dommett

K Kohlhaas

Eric J Zimney

Eric A Stach

Richard D Piner

SonBinh T Nguyen

Rodney S Ruoff
title: Graphene based composite materials
venue: Nature
year: 2006

abstract: This paper reviews recent advances in the modification of graphene and the fabrication of graphene based polymer nanocomposites. Recently, graphene has attracted both academic and industrial interest because it can produce a dramatic improvement in properties at very low filler content. The modification of graphene/graphene oxide and the utilization of these materials in the fabrication of nanocomposites with different polymer matrixes have been explored. Different organic polymers have been used to fabricate graphene filled polymer nanocomposites by a range of methods. In the case of modified graphene based polymer nanocomposites, the percolation threshold can be achieved at a very lower filler loading. Herein, the structure, preparation and properties of polymer/graphene nanocomposites are discussed in general along with detailed examples drawn from the scientific literature.
author_names: Tapas Kuilla

Sambhu Bhadra

Da-hu Yao

Nam Hoon Kim

Saswata Bose

Joong Hee Lee
title: Recent advances in graphene based polymer composites
year: 2010

abstract: Graphene nanosheets were prepared by complete oxidation of pristine graphite followed by thermal exfoliation and reduction. Polyethylene terephthalate (PET)/graphene nanocomposites were prepared by melt compounding. Transmission electron microscopy observation indicated that graphene nanosheets exhibited a uniform dispersion in PET matrix. The incorporation of graphene greatly improved the electrical conductivity of PET, resulting in a sharp transition from electrical insulator to semiconductor with a low percolation threshold of 0.47 vol. A high electrical conductivity of 2.11 S/m was achieved with only 3.0 vol. of graphene. The low percolation threshold and superior electrical conductivity are attributed to the high aspect ratio, large specific surface area and uniform dispersion of the graphene nanosheets in PET matrix.
author_names: Haobin Zhang

Wenge Zheng

Qing Yan

Yong Yang

Jiwen Wang

Zhao-Hui Lu

Guoying Ji

Zhong-Zhen Yu
title: Electrically conductive polyethylene terephthalate/graphene nanocomposites prepared by melt compounding
year: 2010

abstract: Graphene oxide (GO) derived from oxidation of natural graphite contains many active groups that can interact with a great variety of polar moieties. In this work, polypropylene (PP)/graphene oxide nanocomposites using polypropylene (PP) grafted with amine alcohol (PPgDMAE) as compatibilizer were prepared by two different methods. Maleic anhydride grafted PP (PPgMA) was reacted with 2 [2 (dimethylamine) ethoxy] ethanol (DMAE) in the melt for forming amine alcohol functionalized polypropylene (PPgDMAE) Nanocomposites were prepared by two methods. In one method, PP/GO nanocomposite was prepared by direct melt mixing in an internal batch mixer using PPgDMAE as compatibilizer. In another method, a previous mixing of PPgDMAE with GO in hot Xilene was done and then, once the solvent was evaporated, it was incorporated into PP by melt mixing. The microstructure and interface enhancement of the prepared composites were analyzed by Fourier transform infrared spectroscopy (FTIR) Raman, X ray difraction (DRX) contact angle, scanning and transmission electron microscopy (STEM) mechanical, thermal, and electrical properties measurements. Fourier transform infrared spectroscopy (FTIR) revealed the interaction between GO and PPgDMAE. The loading of GO conducted to enhance the composite mechanical properties attributed to the strong interfacial interactions between GO and PPgDMAE. A significant improvement in mechanical thermal stability and electrical properties was observed when nanocomposites were prepared by the solution blending method compared with melt mixing method. This work suggests a potential application of GO in preparation of high performance PP composites. POLYM. COMPOS. 2016. (c) 2016 Society of Plastics Engineers
author_names: Saul Sanchez-Valdes

A G Zapata-Dominguez

J G Martinez-Colunga

Juan Mendez-Nonell

Luis Francisco Ramos Valle

Adriana Berenice Espinoza-Martinez

Ana Beatriz Morales-Cepeda

Tomas Lozano-Ramirez

Pierre G Lafleur

E Ramirez-Vargas
title: Influence of functionalized polypropylene on polypropylene/graphene oxide nanocomposite properties
year: 2018

abstract: The surface area of a single graphene sheet is 2630 m(2)/g, substantially higher than values derived from BET surface area measurements of activated carbons used in current electrochemical double layer capacitors. Our group has pioneered a new carbon material that we call chemically modified graphene (CMG) CMG materials are made from 1 atom thick sheets of carbon, functionalized as needed, and here we demonstrate in an ultracapacitor cell their performance. Specific capacitances of 135 and 99 F/g in aqueous and organic electrolytes, respectively, have been measured. In addition, high electrical conductivity gives these materials consistently good performance over a wide range of voltage scan rates. These encouraging results illustrate the exciting potential for high performance, electrical energy storage devices based on this new class of carbon material.
author_names: Meryl D Stoller

Sungjin Park

Yanwu Zhu

Jin-ho An

Rodney S Ruoff
title: Graphene based ultracapacitors.
venue: Nano letters
year: 2008

abstract: Abstract Despite the great potential of graphene as the nanofiller, to achieve homogeneous dispersion remains the key challenge for effectively reinforcing the polymer. Here, we report an eco friendly strategy for fabricating the polymer nanocomposites with well dispersed graphene sheets in the polymer matrix via first coating graphene using polypropylene (PP) latex and then melt blending the coated graphene with PP matrix. A ~75% increase in yield strength and a ~74% increase in the Young's modulus of PP are achieved by addition of only 0.42 vol% of graphene due to the effective external load transfer. The glass transition temperature of PP is enhanced by ~2.5 degC by incorporating only 0.041 vol% graphene. The thermal oxidative stability of PP is also remarkably improved with the addition of graphene, for example, compared with neat PP, the initial degradation temperature is enhanced by 26 degC at only 0.42 vol% of graphene loading.
author_names: Pingan Song

Zhenhu Cao

Yuanzheng Cai

Liping Zhao

Zhengping Fang

Shenyuan Fu
title: Fabrication of exfoliated graphene based polypropylene nanocomposites with enhanced mechanical and thermal properties
year: 2011