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Gad Marom

Bio: Gad Marom is an academic researcher from Hebrew University of Jerusalem. The author has contributed to research in topics: Nanocomposite & Carbon nanotube. The author has an hindex of 23, co-authored 24 publications receiving 5971 citations. Previous affiliations of Gad Marom include Hong Kong University of Science and Technology & Illinois Institute of Technology.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a review of the current understanding of carbon nanotubes and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT-based functionalization on the properties of polymers.
Abstract: Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.

2,849 citations

Journal ArticleDOI
TL;DR: Recent progress and advances that have been made on dispersion of carbon nanotubes in aqueous and organic media by non-covalent adsorption of surfactants and polymers are reviewed.

1,417 citations

Journal ArticleDOI
TL;DR: In this article, the dispersive effects achieved by a wide range of surface active agents, as well as surface oxidation and functionalization, are investigated for uniform, multi-walled carbon nanotube (MWNT) distribution in water-soluble (poly(ethylene glycol)) and water-insoluble polymers.
Abstract: Microscale aggregate formation, resulting from high intrinsic filler attractions, is one of the major issues in nanocomposite preparation and processing. Herein, the dispersive effects achieved by a wide range of surface-active agents, as well as surface oxidation and functionalization, are investigated. The aim of our research is to form a uniform, multiwalled carbon nanotube (MWNT) distribution in water-soluble (poly(ethylene glycol)) and water-insoluble (polypropylene) polymers. In order to understand the surface-charge-related stability of the treated nanotubes solutions, zeta-potential measurements are applied. Quantification of the state of the MWNT dispersion is derived from particle-size analysis, while visual characterization is based on optical and electron microscopy. To estimate the nucleating ability of the surface-modified carbon nanotubes, the temperature of crystallization and the degree of crystallinity are calculated from differential scanning thermograms. Finally, we suggest general guidelines to produce uniform MWNT dispersions using a dispersive agent and/or surface treatment in water-soluble and water-insoluble polymers.

380 citations

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TL;DR: In this article, the authors examined two types of carbon fibres with different mechanical properties but similar surface treatments, and the results of all the mechanical properties examined (modulus, strength, stress intensity factor, fracture energies) under quasi-static and fast testing conditions do not show any synergism.
Abstract: A positive or negative hybrid effect in hybrid composites is defined as a positive or negative deviation of a certain mechanical property from the rule-of-mixtures behaviour. The question of hybrid effects is first examined with special hybrids which have been chosen so that the effect of the fibre-matrix interface is minimized. The hybrids examined consisted of two types of carbon fibres with different mechanical properties but similar surface treatments. The results of all the mechanical properties examined (modulus, strength, stress intensity factor, fracture energies) under quasi-static and fast testing conditions do not show any synergism. In view of these results a second hybrid system of E-glass fibre/AS carbon fibre-reinforced epoxy has been chosen. In this system both the mechanical properties of the fibres and the interface which they form with the resin are entirely different. None of the mechanical properties, excluding the fracture energies, show any signs of a hybrid effect. The fracture energy results, however, show the existence of a negative hybrid effect. A theory which sets upper and lower bounds for the hybrid effect is proposed, and the conditions for the occurrence of either a positive or a negative effect are discussed.

228 citations

Journal ArticleDOI
TL;DR: In this article, the effect of modifying the network structure on moisture absorption of epoxies was investigated, and the network was modified by crosslinking the epoxides wth various mono/diamine proportions, resulting in decreasing density and increasing free volume.
Abstract: An investigation of the effect of modifying the network structure on moisture absorption of epoxies was performed. The network was modified by crosslinking the epoxides wth various mono/diamine proportions, resulting in decreasing density and increasing free volume. It was discovered, however, that concomitant effects, i.e., the formation of a two-phase structure, and changes in resin polarity and in resin-water affiniy predominated. Thus, compositions with higher chain molecular weights between crosslink points yet exhibited lower diffusion coeficients. Also, when drastic swelling conditions (such as a water-boil treatment) were employed, moisture absorption was facilitated by penetration via newly formed microcracks.

206 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the structure, preparation and properties of polymer/graphene nanocomposites are discussed in general along with detailed examples drawn from the scientific literature, and the percolation threshold can be achieved at a very lower filler loading.

2,999 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the current understanding of carbon nanotubes and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT-based functionalization on the properties of polymers.
Abstract: Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.

2,849 citations

Journal ArticleDOI
TL;DR: It is reported that GO is an amphiphile with hydrophilic edges and a more hydrophobic basal plane, and the ease of its conversion to chemically modified graphene could enable new opportunities in solution processing of functional materials.
Abstract: Graphite oxide sheet, now called graphene oxide (GO), is the product of chemical exfoliation of graphite and has been known for more than a century. GO has been largely viewed as hydrophilic, presumably due to its excellent colloidal stability in water. Here we report that GO is an amphiphile with hydrophilic edges and a more hydrophobic basal plane. GO can act like a surfactant, as measured by its ability to adsorb on interfaces and lower the surface or interfacial tension. Since the degree of ionization of the edge −COOH groups is affected by pH, GO’s amphiphilicity can be tuned by pH. In addition, size-dependent amphiphilicity of GO sheets is observed. Since each GO sheet is a single molecule as well as a colloidal particle, the molecule−colloid duality makes it behave like both a molecular and a colloidal surfactant. For example, GO is capable of creating highly stable Pickering emulsions of organic solvents like solid particles. It can also act as a molecular dispersing agent to process insoluble mat...

1,572 citations

Journal ArticleDOI
TL;DR: Recent progress and advances that have been made on dispersion of carbon nanotubes in aqueous and organic media by non-covalent adsorption of surfactants and polymers are reviewed.

1,417 citations

Journal ArticleDOI
TL;DR: In this paper, the properties of lactic acid based polymers and the correlation to the structure of the polymers are discussed, including the thermophysical properties, the solubility, the miscibility, and the mechanical properties.

1,368 citations