Showing papers on "Polymer nanocomposite published in 2011"
TL;DR: A survey of the literature on polymer nanocomposites with graphene-based fillers including recent work using graphite nanoplatelet fillers is presented in this article, along with methods for dispersing these materials in various polymer matrices.
2,782 citations
TL;DR: In this article, the status of worldwide research in the thermal conductivity of carbon nanotubes and their polymer nanocomposites is reviewed, as well as the relationship between thermal conductivities and the micro- and nano-structure of the composites.
2,102 citations
TL;DR: In this paper, the synthesis of polyhedral oligomeric silsesquioxane (T8-POSS) compounds, the miscibility of POSS derivatives and polymers, the preparation of both multifunctional and monofunctional monomers, and the applications of several high-performance POSS nanocomposites in such systems as light emitting diodes, liquid crystals, photo-resist materials, low-dielectric constant materials, self-assembled block copolymers, and nanoparticles.
886 citations
TL;DR: In this article, the authors present an overview of graphene/polymer nanocomposites discussing preparation, properties and potential applications, and the challenges and outlook of these emerging polymer nanocompositionites are also discussed.
Abstract: Graphene has attracted the attention of a growing number of scientists from several disciplines due to its remarkable physical properties and chemical functionalisation capabilities. This review presents an overview of graphene/polymer nanocomposites discussing preparation, properties and potential applications. The challenges and outlook of these emerging polymer nanocomposites are also discussed.
686 citations
TL;DR: In this paper, 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.
572 citations
TL;DR: This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites and focuses on the following two topics: electrical conductivity and piezoresistivity of CNT/.
Abstract: In recent years, nanocomposites based on various nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a realistic alternative to conventional smart materials, largely due to their superior electrical properties. Great interest has been generated in building highly sensitive strain sensors with these new nanocomposites. This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites. We focus on the following two topics: electrical conductivity and piezoresistivity of CNT/polymer nanocomposites, and the relationship between them by considering the internal conductive network formed by CNTs, tunneling effect, aspect ratio and piezoresistivity of CNTs themselves, etc. Many recent experimental, theoretical and numerical studies in this field are described in detail to uncover the working mechanisms of this new type of strain sensors and to demonstrate some possible key factors for improving the sensor sensitivity.
537 citations
TL;DR: In this paper, the effect of different nanoparticles, their dispersion and the used modifiers, on polymer thermal stability was highlighted, highlighting the effect that hydrogen or covalent bonds can increase the adhesion of nanoparticles with the polymer matrix, resulting in higher dispersion degrees.
466 citations
TL;DR: The impact of CNT density on thermal conduction considering boundary resistances, increased defect concentrations, and the possibility of suppressed phonon modes in the CNTs is discussed.
Abstract: Nanostructured composites containing aligned carbon nanotubes (CNTs) are very promising as interface materials for electronic systems and thermoelectric power generators. We report the first data for the thermal conductivity of densified, aligned multiwall CNT nanocomposite films for a range of CNT volume fractions. A 1 vol % CNT composite more than doubles the thermal conductivity of the base polymer. Denser arrays (17 vol % CNTs) enhance the thermal conductivity by as much as a factor of 18 and there is a nonlinear trend with CNT volume fraction. This article discusses the impact of CNT density on thermal conduction considering boundary resistances, increased defect concentrations, and the possibility of suppressed phonon modes in the CNTs.
459 citations
TL;DR: In this paper, the authors highlight the frontier scientific research in the development of polymer nanocomposites for electrical energy storage applications, including the increase of the dielectric permittivity using high-permittivity ceramic fillers and conductive dopants, preparation of uniform composite films based on surface-functionalized fillers, and utilization of the interfacial coupling effect.
Abstract: This review highlights the frontier scientific research in the development of polymer nanocomposites for electrical energy storage applications. Considerable progress has been made over the past several years in the enhancement of the energy densities of the polymer nanocomposites via tuning the chemical structures of ceramic fillers and polymer matrix and engineering the polymer–ceramic interfaces. This article summarizes a range of current approaches to dielectric polymer nanocomposites, including the ferroelectric polymer matrix, increase of the dielectric permittivity using high-permittivity ceramic fillers and conductive dopants, preparation of uniform composite films based on surface-functionalized fillers, and utilization of the interfacial coupling effect. Primary attentions have been paid to the dielectric properties at different electric fields and their correlation with film morphology, chemical structure, and filler concentration. This article concludes with a discussion of scientific issues that remain to be addressed as well as recommendations for future research. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1421–1429, 2011
448 citations
TL;DR: The interaction between carbon nanotubes and polymers is critically reviewed in this article, where various techniques of interaction measurements, including experimental and modelling studies, are described, including wetting, spectroscopy and probe microscopy techniques are discussed in detail.
426 citations
TL;DR: It is found that the coarsening or aggregation process of the NPs is sensitive to the temperature, and the aggregation extent reaches the minimum in the case of moderate polymer-filler interaction, because in this case a good dispersion is obtained.
Abstract: It is a great challenge to fully understand the microscopic dispersion and aggregation of nanoparticles (NPs) in polymer nanocomposites (PNCs) through experimental techniques. Here, coarse-grained molecular dynamics is adopted to study the dispersion and aggregation mechanisms of spherical NPs in polymer melts. By tuning the polymer–filler interaction in a wide range at both low and high filler loadings, we qualitatively sketch the phase behavior of the PNCs and structural spatial organization of the fillers mediated by the polymers, which emphasize that a homogeneous filler dispersion exists just at the intermediate interfacial interaction, in contrast with traditional viewpoints. The conclusion is in good agreement with the theoretically predicted results from Schweizer et al. Besides, to mimick the experimental coarsening process of NPs in polymer matrixes (ACS Nano2008, 2, 1305), by grafting polymer chains on the filler surface, we obtain a good filler dispersion with a large interparticle distance. C...
TL;DR: The synthesis and properties of graphene and its derivatives are summarized, and an overview of the latest research dedicated to the fabrication of polymer composites for different applications is provided, including mechanical, electrical, optical and thermal.
Abstract: Graphene constitutes a two dimensional sp2 hybridized carbon material with outstanding electrical and mechanical properties. To date, novel methods for producing large quantities of graphene and its derivatives (doped or functionalized graphenes, nanoribbons and nanoplatelets) are emerging, and research dedicated to the fabrication of polymer nanocomposites using graphenes has started. In this Research News, we summarize the synthesis and properties of graphene and its derivatives, and provide an overview of the latest research dedicated to the fabrication of polymer composites for different applications, including mechanical, electrical, optical and thermal. Some of the recently fabricated composites exhibit outstanding properties, however, it is vital to understand the chemistry and physics of the interphases established between the polymer and the graphene surfaces. The challenges in the fabrication of super robust and highly conducting composites using graphenes are also discussed. It is believed that graphene-based polymer composites will result in commercial products if their interphases and reactivity are carefully controlled.
TL;DR: In this article, a transparent polymer nanocomposites with high refractive index were prepared by grafting polymer chains onto anatase TiO2 nanoparticles via a combination of phosphate ligand engineering and alkyne-azide "click" chemistry.
Abstract: Transparent polymer nanocomposites with high refractive index were prepared by grafting polymer chains onto anatase TiO2 nanoparticlesvia a combination of phosphate ligand engineering and alkyne-azide “click” chemistry. Highly crystalline TiO2 nanoparticles with 5 nm diameter were synthesized by a solvothermal method and used as high refractive index filler. The synthesized phosphate-azide ligand anchors strongly onto the TiO2 nanoparticle surface and the azide end group allows for attachment of poly(glycidyl methacrylate) (PGMA) polymer chains through an alkyne-azide “click” reaction. The refractive index of the composite material increased linearly from 1.5 up to 1.8 by increasing the loading of TiO2 particles to 30 vol % (60 wt %). UV-vis spectra show that the nanocomposites exhibited a transparency around 90% throughout the visible light range. It was also found that the PGMA-grafted TiO2 nanoparticles can be well dispersed into a commercial epoxy resin, forming transparent high refractive index TiO2-epxoy nanocomposites.
TL;DR: The BCNC obtained through cellulose treatment under controlled conditions were associated with several desirable properties and appear to be superior over the conventional methods of nanocrystals production.
TL;DR: Financial support provided by the Ministerio de Ciencia e Innovacion (MCINN) through the Project MAT 2010-18749 and the CSIC for a JAE-pre contract.
Abstract: Financial support provided by the Ministerio de Ciencia e Innovacion (MCINN) through the Project MAT 2010-18749. N.B. thanks the CSIC for a JAE-pre contract.
TL;DR: In this paper, a mixture of high aspect ratio copper nanowires with polystyrene solutions was used to produce polymer nanocomposites with segregated nanowire networks resembling cell-like structures.
Abstract: Metal nanowire/polymer nanocomposites are advanced materials for electrically conductive applications. Metal nanowires have high surface area, high aspect ratios, and high electrical conductivity, which are critical for the synthesis of conductive polymer nanocomposites using extremely low amounts of conductive filler. In this work, lightweight, thin, and highly conductive copper nanowire/polystyrene nanocomposites were prepared using a novel method of nanocomposite preparation termed miscible solvent mixing and precipitation (MSMP). Suspensions of high aspect ratio copper nanowires were mixed with polystyrene solutions to produce polymer nanocomposites with segregated nanowire networks resembling cell-like structures. Highly electrically conductive networks of nanowires were obtained beyond a percolation threshold of ϕc = 0.67 vol% and percolated nanocomposites showed electrical conductivities up to 104 S m−1, which exceeds the conductivity range generally reported for carbon nanofiller-based nanocomposites. The significant potential of these nanocomposites for electrical applications like electromagnetic interference (EMI) shielding was further demonstrated. Metal nanowire/polymer nanocomposites sheets of 0.21 mm in thickness exhibited EMI SE of more than 20 dB for copper nanowire concentrations of only 1.3 vol%.
TL;DR: In this article, multi-wall carbon nanotube (MWCNT)/aromatic polyamide (PA) nanocomposite membranes were synthesized by a polymer grafting process.
TL;DR: In this article, the authors reported the excellent reinforcement properties of polymer nanocomposites by the incorporation of nanodiamond (ND), which can approach the values of single diamond crystal.
Abstract: Carbon-based nanomaterials, such as carbon nanotubes, are well-known for their unique physical properties. They have attracted interest as reinforcing fillers because of their superb mechanical properties (Young’s modulus ≥1 TPa and tensile strength = 100–150 GPa). However, the success of the reinforcement has been limited because of their tendency to form agglomerates in polymer matrices. We report the excellent reinforcement properties of polymer nanocomposites by the incorporation of nanodiamond (ND). ND has been expected to offer polymer nanocomposites optimal properties because of its smooth surface and excellent optical, mechanical, and thermal properties, which can approach the values of single diamond crystal. We prepared poly(vinyl alcohol) (PVA)/ND nanocomposites by a simple casting method from aqueous medium and achieved the high dispersibility of ND in the PVA matrices. The resulting nanocomposites had excellent properties derived both from ND and PVA. The Young’s modulus of the nanocomposites...
TL;DR: The morphological structure of mixtures of homopolymers with inorganic nanoparticles, onto which polymer chain ends are grafted, is described in this paper, where morphological phase diagrams are delineated in terms of the nanoparticle curvature, the chain grafting density, the grafting chain degree of polymerization, N, that of the free host chains, P, and the thermodynamic (Flory-Huggins) interaction parameter, χ, between the host and grafted chains.
Abstract: The morphological structure of mixtures of homopolymers with inorganic nanoparticles, onto which polymer chain ends are grafted, is described herein. In the bulk, at very low grafting densities, Σ, the morphology of these polymer nanocomposites (PNCs) is largely determined by the attractive enthalpic interactions between the nanoparticle cores, mediated by entropic interactions with the grafted polymer chains. These competing interactions have been shown to be responsible for the anisotropic organization of the nanoparticles within polymer hosts. At high grafting densities, however, even in cases where the host chains and the grafted chains are of identical chemical structure, the entropic brush layer/free host chain interactions are dominant, leading to miscibility (isotropic dispersion of the nanoparticles within the polymer host) or to microscopic and macroscopic phase separation. In the limit of very small nanoparticles, radii R ≈ 1 nm, the brush/melt interactions are not important yet the nanoparticles exhibit a high tendency toward miscibility within homopolymer hosts. This paper begins with a discussion of the bulk morphology of PNCs in order to provide a context for the subsequent description of the morphological structure of thin film brush coated nanoparticle–homopolymer mixtures. A fundamental difference between these bulk and thin film PNCs is that a preferential attraction of grafted nanoparticles to interfaces renders thin film PNCs thermodynamically less stable than their bulk analogs. Morphological phase diagrams, which delineate regimes where the PNCs are miscible, incompatible or partially miscible, are parameterized in terms of the nanoparticle curvature, the chain grafting density, the grafting chain degree of polymerization, N, that of the free host chains, P, and the thermodynamic (Flory–Huggins) interaction parameter, χ, between the host and grafted chains.
TL;DR: An innovative, chemical strategy for the synthesis of polymer electrolytes whose ion-conducting channels are physically and chemically modulated by the ionic (not electronic) conductive, functionalized graphenes is reported for a fundamental understanding of ion and mass transport occurring in nanoscale ionic clusters.
Abstract: The chemistry and structure of ion channels within the polymer electrolytes are of prime importance for studying the transport properties of electrolytes as well as for developing high-performance electrochemical devices. Despite intensive efforts on the synthesis of polymer electrolytes, few studies have demonstrated enhanced target ion conduction while suppressing unfavorable ion or mass transport because the undesirable transport occurs through an identical pathway. Herein, we report an innovative, chemical strategy for the synthesis of polymer electrolytes whose ion-conducting channels are physically and chemically modulated by the ionic (not electronic) conductive, functionalized graphenes and for a fundamental understanding of ion and mass transport occurring in nanoscale ionic clusters. The functionalized graphenes controlled the state of water by means of nanoscale manipulation of the physical geometry and chemical functionality of ionic channels. Furthermore, the confinement of bound water within...
TL;DR: In this article, the authors have fabricated new types of polymer hydrogels and polymer nanocomposite gels with novel organic/inorganic network structures, such as nanocomposition gels (NC gels) and soft polymer Nanocomposites (M-NCs), with a wide range of clay contents.
Abstract: We have fabricated new types of polymer hydrogels and polymer nanocomposites, that is, nanocomposite gels (NC gels) and soft polymer nanocomposites (M-NCs), with novel organic/inorganic network structures. Both NC gels and M-NCs were synthesized by in situ free-radical polymerization in the presence of exfoliated clay platelets in aqueous systems and were obtained in various forms and sizes with a wide range of clay contents. Here, disk-like inorganic clay nanoparticles function as multifunctional crosslinkers to form new types of network systems. NC gels have extraordinary optical, mechanical and swelling/deswelling properties, as well as a number of new characteristics relating to optical anisotropy, polymer/clay morphology, biocompatibility, stimuli-sensitive surfaces, micropatterning and so on. The M-NCs also exhibit dramatic improvements in optical and mechanical properties including ultrahigh reversible extensibility and well-defined yielding behavior, despite their high clay contents. Thus, the serious disadvantages (intractability, mechanical fragility, optical turbidity, poor processing ability, low stimulus sensitivity and so on) associated with the conventional, chemically crosslinked polymeric materials were overcome in NC gels and M-NCs.
TL;DR: Shape memory polymers are a class of polymers that can be deformed to stable temporary shapes and recover their permanent shape only when exposed to an external stimulus.
Abstract: Shape memory polymers (SMPs) are a class of polymers that can be deformed to stable temporary shapes and recover their permanent shape only when exposed to an external stimulus. [ 1,2 ] The unique ability to actuate SMPs through the setting of temporary shapes and then actuating to a permanent shape has been utilized for a number of applications in various fi elds. Many prototype systems have been developed, including an intravascular device to remove blood clots, [ 3 ] a self-peeling reversible dry adhesive, [ 4,5 ] a biodegradable self-tightening suture, [ 6 ] an active microfl uidic device, [ 7 ] self-healing surfaces, [ 8 ]
TL;DR: In this article, the reinforcement of laser sintered polyamides with carbon nanofibres (CNFs) was investigated, and the effects of CNF addition on the processing parameters and mechanical properties of laser-sintered parts have been investigated.
TL;DR: Three mechanisms are proposed for the assembly of ordered, layered structures of graphene oxide, formed via the vacuum-assisted self-assembly of a dispersion of the two-dimensional nanosheets, providing insight into possibilities for creation of ordered graphene oxide-polymer nanocomposites, as well as the postfabrication modification of single-component graphene oxide papers.
Abstract: Three mechanisms are proposed for the assembly of ordered, layered structures of graphene oxide, formed via the vacuum-assisted self-assembly of a dispersion of the two-dimensional nanosheets. Thes...
TL;DR: In this article, the nucleation of the electroactive β-phase of poly(vinylidene fluoride), PVDF, by the addition of CoFe2O4 and NiFe 2O4 nanoparticles was reported.
Abstract: Multiferroic and magnetoelectric materials show enormous potential for technological developments. Multiferroic composites are more attractive for applications due to their enhanced properties with respect to single-phase multiferroic materials. In this paper we report on the nucleation of the electroactive β-phase of poly(vinylidene fluoride), PVDF, by the addition of CoFe2O4 and NiFe2O4 nanoparticles in order to prepare poly(vinylidene fluoride)/ferrite nanocomposite for multiferroic and magnetoelectric applications,. The dispersed ferrite nanofiller particles strongly enhance the nucleation of the β-phase of the polymer matrix. In this way, magnetoelectric polymer nanocomposites can be processed avoiding the usual α- to β-phase transformation by stretching of the polymer matrix.
TL;DR: In this paper, the percolation concentration of the composites prepared by solvent method is less than those of melt blended method, while the mechanical performance of the composite material is higher than melt blended.
TL;DR: Overall, this feasibility study demonstrates the ability of using model Laponite cross-linked PEO nanocomposites to create bioactive scaffolds.
TL;DR: In this paper, the authors have successfully decorated carbon nanotubes with silver (Ag-CNTs) using N, N-dimethylformamide (DMF) as a reductant.
Abstract: We have successfully decorated carbon nanotubes with silver (Ag–CNTs) using N, N-dimethylformamide (DMF) as a reductant. The Ag–CNTs were charactered by TGA, XRD, TEM and Raman spectra to confirm that silver nanoparticles were uniformly decorated onto the CNTs. Then the Ag–CNTs were used as fillers to prepare the nanocomposites with two polymers: polypropylene (PP) and polystyrene (PS) by means of two different methods: i.e. melt compounding and solution mixing, respectively. The results showed that the Ag–CNTs could effectively improve the electrical conductivity and mechanical properties of PP and PS as compared to pristine CNTs. It was found that the solution mixing was better than the melt mixing in terms of dispersion of CNTs and electrical conductivity. The mechanisms for the results have been discussed.
TL;DR: In this paper, the stiffness of cellulose nanocrystals or whiskers has been investigated and a correlation exists between stiffness of the films and aspect ratio of the constituent rod-like nanoparticles.
TL;DR: In this article, the effects of nanotube length, diameter, and wall number on the pull-out process were studied for two-phase CNT/polymer nanocomposites with only consideration of van der Waals (vdW) interaction.