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Book ChapterDOI: 10.1016/B978-0-323-31306-3.00006-3

PET Nanocomposites: Preparation and Characterization

01 Jan 2015-pp 99-111
Abstract: The chapter deals with a brief account of various characterizing techniques using for PET-based nanocomposites in this chapter mainly explained about the morphology, thermal behavior, tensile behavior, etc

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Open accessJournal ArticleDOI: 10.1021/JP040650F
Claire Berger1, Zhimin Song1, Tianbo Li1, Xuebin Li1  +7 moreInstitutions (1)
Abstract: We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically 3 graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H-SiC, and characterized by surface-science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kOhm to 225 kOhm at 4 K, with positive magnetoconductance). Low resistance samples show characteristics of weak-localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 10^{12} cm^{-2} per graphene sheet. The most highly-ordered sample exhibits Shubnikov - de Haas oscillations which correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic techniques, and we demonstrate modulation of the film conductance using a top-gate electrode. These key elements suggest electronic device applications based on nano-patterned epitaxial graphene (NPEG), with the potential for large-scale integration.

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Topics: Graphene (60%), Quantum Hall effect (58%)

171 Citations


Journal ArticleDOI: 10.1002/PAT.4081
Abstract: Zinc phosphinate (Exolit OP950), nanosilica particles and polyethylene terephthalate (PET) have been blended and thereafter melt-spinned to develop a new flame retardant (FR) system for PET textiles The effects of the two types of nanosilica fillers on the wettability, dispersibility and thermal properties were studied to determine how the degree of hydrophilicity affects the PET matrix The influence of the blends on thermal transitions has been investigated by differential scanning calorimetry (DSC), the thermal stability of the polymer/FR blend composites has been assessed by thermogravimetric analysis (TGA) and cone calorimetry has been used to study the fire reaction It was noticed that the nanoparticles have a limited influence on the thermal transitions of the PET matrix, but zinc phosphinate acted as a plasticizer and a compatibilizer for the more hydrophobic particles Thermogravimetric analysis results showed that the addition of silica particles and FR compound improves slightly the thermal stability of the PET systems under nitrogen and air atmospheres Furthermore, it was noticed that the incorporation of nanoparticles gives almost no improvement in the PET fire reaction from cone calorimeter experiments However, in the presence of Exolit OP950, the systems acted as FR in PET films and knitted structures The heat release rate during the combustion decreased, and the thermal behaviors of these structures were closed to those with 10% wt of Exolit OP950 Copyright © 2017 John Wiley & Sons, Ltd

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4 Citations


Open accessJournal ArticleDOI: 10.33412/APANAC.2021.3068
20 Aug 2021-
Abstract: En este articulo se presenta el desarrollo de un material compuesto a base de Polietileno de Tereftalato (PET) y virutas metalicas de acero y aluminio, desde el proceso empleado para la fabricacion de placas (probetas), hasta la realizacion de tomografia computarizada y ensayos de tension. A pesar de que los resultados de resistencia del material han sido menores respecto a los que presenta un material PET virgen, este estudio ha permitido definir las condiciones del proceso de fabricacion de las placas.

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1 Citations


Book ChapterDOI: 10.1016/B978-0-12-816683-3.00007-4
Anu Kalia1Institutions (1)
01 Jan 2019-
Abstract: Nano-engineering, an emerging engendering field, encompasses bottom-up synthesis of diverse novel materials/structures that can be assembled or augmented to fabricate innovative devices and systems showcasing unique multi-functionalities. It has entrailed down the beverage production, processing and preservation, packaging, quality monitoring, and shelf life/safety-related technologies through design of predictive models, tools/apparatus at nanoscale. The nano-enabled packaging panacea spans over supplementation of nanomaterials (could be inorganic or organic in origin) in commercially viable synthetic polymers to embellish their mechanical, optical, and thermal properties besides contriving novel antimicrobial, moisture/gas adsorbing/absorbing or repelling, and bio-catalytical functionalities thereby enhancing the shelf life, nutritional quality, and safety of the packaged beverages. The nano-processing interventions rather involve developing beverages fortified with nanoscale nutrients (zinc, iron, calcium, and selenium); nutraceuticals (flavonoids and phenolics); biocolorants or dietary supplements including secondary metabolites like beta-carotene, lycopene; flavor concealment or multiple flavor augmentations; and creation of new textures of diverse structural components. This chapter explores the extent of introgression of nano-interventions in beverage industry to address the daunting challenges of development of novel beverage formulations, and recent nano-trends in beverages as functional foods.

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Topics: Beverage industry (65%)

1 Citations

References
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Open accessJournal ArticleDOI: 10.1126/SCIENCE.1102896
Kostya S. Novoselov1, Andre K. Geim1, Sergey V. Morozov, Da Jiang1  +4 moreInstitutions (1)
22 Oct 2004-Science
Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

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Topics: Carbon film (57%), Hall effect (55%), Ambipolar diffusion (54%) ...read more

48,846 Citations


Journal ArticleDOI: 10.1038/NATURE04969
20 Jul 2006-Nature
Abstract: The remarkable mechanical properties of carbon nanotubes arise from the exceptional strength and stiffness of the atomically thin carbon sheets (graphene) from which they are formed. In contrast, bulk graphite, a polycrystalline material, has low fracture strength and tends to suffer failure either by delamination of graphene sheets or at grain boundaries between the crystals. Now Stankovich et al. have produced an inexpensive polymer-matrix composite by separating graphene sheets from graphite and chemically tuning them. The material contains dispersed graphene sheets and offers access to a broad range of useful thermal, electrical and mechanical properties. Individual sheets of graphene can be readily incorporated into a polymer matrix, giving rise to composite materials having potentially useful electronic properties. 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 defects1,2,3; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties4,5,6,7,8. 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 graphite9 and molecular-level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene–graphene composite formed by this route exhibits a percolation threshold10 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 nanotubes11; at only 1 volume per cent, this composite has a conductivity of ∼0.1 S m-1, sufficient for many electrical applications12. 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.

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Topics: Graphene oxide paper (71%), Graphene foam (66%), Graphene nanoribbons (66%) ...read more

11,078 Citations


Journal ArticleDOI: 10.1016/J.PROGPOLYMSCI.2003.08.002
Suprakas Sinha Ray1, Masami Okamoto1Institutions (1)
Abstract: A review is given of the academic and industrial aspects of the preparation, characterization, materials properties, crystallization behavior, melt rheology, and processing of polymer/layered silicate nanocomposites. These materials are attracting considerable interest in polymer science research. Hectorite and montmorillonite are among the most commonly used smectite-type layered silicates for the preparation of nanocomposites. Smectites are a valuable mineral class for industrial applications because of their high cation exchange capacities, surface area, surface reactivity, adsorptive properties, and, in the case of hectorite, high viscosity and transparency in solution. In their pristine form they are hydrophilic in nature, and this property makes them very difficult to disperse into a polymer matrix. The most common way to remove this difficulty is to replace interlayer cations with quarternized ammonium or phosphonium cations, preferably with long alkyl chains. A wide range of polymer matrices is covered in this review, with special emphasis on biodegradable polymers. In general, polymer/layered silicate nanocomposites are of three different types, namely (1) intercalated nanocomposites , for which insertion of polymer chains into a layered silicate structure occurs in a crystallographically regular fashion, with a repeat distance of few nanometers, regardless of polymer to clay ratio, (2) flocculated nanocomposites , for which intercalated and stacked silicate layers flocculated to some extent due to the hydroxylated edge–edge interactions of the silicate layers, and (3) exfoliated nanocomposites , for which the individual silicate layers are separated in the polymer matrix by average distances that depend only on the clay loading. This new family of composite materials frequently exhibits remarkable improvements of material properties when compared with the matrix polymers alone or conventional micro- and macro-composite materials. Improvements can include a high storage modulus, both in solid and melt states, increased tensile and flexural properties, a decrease in gas permeability and flammability, increased heat distortion temperature, an increase in the biodegradability rate of biodegradable polymers, and so forth.

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Topics: Polymer clay (58%), Organoclay (56%), Silicate (56%) ...read more

6,073 Citations


Open accessJournal ArticleDOI: 10.1021/JP040650F
Claire Berger1, Zhimin Song1, Tianbo Li1, Xuebin Li1  +7 moreInstitutions (1)
Abstract: We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically three graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H−SiC, and characterized by surface science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kΩ to 225 kΩ at 4 K, with positive magnetoconductance). Low-resistance samples show characteristics of weak localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 1012 cm-2 per graphene sheet. The most highly ordered sample exhibits Shubnikov−de Haas oscillations that correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic...

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Topics: Graphene (60%), Quantum Hall effect (59%), Weak localization (55%) ...read more

3,160 Citations


Journal ArticleDOI: 10.1021/CM0630800
Abstract: A detailed analysis of the thermal expansion mechanism of graphite oxide to produce functionalized graphene sheets is provided. Exfoliation takes place when the decomposition rate of the epoxy and hydroxyl sites of graphite oxide exceeds the diffusion rate of the evolved gases, thus yielding pressures that exceed the van der Waals forces holding the graphene sheets together. A comparison of the Arrhenius dependence of the reaction rate against the calculated diffusion coefficient based on Knudsen diffusion suggests a critical temperature of 550 °C which must be exceeded for exfoliation to occur. As a result of their wrinkled nature, the functionalized and defective graphene sheets do not collapse back to graphite oxide but are highly agglomerated. After dispersion by ultrasonication in appropriate solvents, statistical analysis by atomic force microscopy shows that 80% of the observed flakes are single sheets.

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Topics: Graphene oxide paper (68%), Graphite oxide (64%), Graphene (60%) ...read more

3,151 Citations


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No. of citations received by the Paper in previous years
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20041