Elastomer Nanocomposites

2008 ◽  
Vol 81 (3) ◽  
pp. 384-469 ◽  
Author(s):  
Madhuchhanda Maiti ◽  
Mithun Bhattacharya ◽  
Anil K. Bhowmick
Keyword(s):  
Carbon Nanotubes ◽  
High Performance ◽  
Volume Fraction ◽  
Layered Silicate ◽  
Barrier Properties ◽  
Review Article ◽  
Layered Silicates ◽  
Structure And Properties ◽  
Uniform Dispersion ◽  
Low Volume

Abstract Recently, elastomer - nanocomposites reinforced with low volume fraction of nanofillers have attracted great interest due to their fascinating properties. The incorporation of nanofillers such as layered silicate clays, carbon nanotubes, nanofibers, calcium carbonate, metal oxides or silica nanoparticles into elastomers improves significantly their mechanical, thermal, dynamic mechanical, barrier properties, flame retardancy, etc. The properties of nanocomposites depend greatly on the chemistry of polymer matrices, nature of nanofillers, and the method in which they are prepared. The uniform dispersion of nanofillers in elastomer matrices is a general prerequisite for achieving desired mechanical and physical characteristics. In this review article, current developments in the field of elastomer nanocomposites reinforced with layered silicates, silica, carbon nanotubes, nanofibers and various other nanoparticles have been addressed. Attention has been paid to the structure and properties of such high-performance nanocomposites, along with the theories and models existing in this field.

High volume fraction and uniform dispersion of carbon nanotubes in aluminium powders

2010 ◽  
Vol 5 (6) ◽  
pp. 379 ◽  
Author(s):  
Zhiqiang Li ◽  
Lin Jiang ◽  
Genlian Fan ◽  
Yong Xu ◽  
Di Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Volume Fraction ◽  
High Volume ◽  
High Volume Fraction ◽  
Uniform Dispersion

Organophilic Layered Silicate Modified Vinylester-Urethane Hybrid Resins: Structure and Properties

2008 ◽  
Vol 16 (8) ◽  
pp. 547-554
Author(s):  
M.-C. Corobea ◽  
D. Donescu ◽  
S. Grishchuk ◽  
N. Castellà ◽  
A.A. Apostolov ◽  
...  
Keyword(s):  
Layered Silicate ◽  
Compact Tension ◽  
Mechanical Tests ◽  
Layered Silicates ◽  
Sorption Behavior ◽  
Structure And Properties ◽  
Quaternary Amine ◽  
X Ray ◽  
Hybrid Resin ◽  
Crosslinking Reactions

A commercial vinylester-urethane (VEUH) hybrid resin was modified with organophilic layered silicates (OLS), incorporated in various amounts (0.1 to 5 wt.%). As organophilic intercalants of the layered silicate (synthetic fluorohectorite) trimethyl dodecylamine (TMDA) and octadecylamine - N,N-bis[allyl(2-hydroxypropyl)ether] (OAE) served. The latter quaternary amine was expected to support the intercalation/exfoliation of the silicate by participating in the crosslinking reactions. Both OLS types became intercalated based on X-ray diffractograms (XRD). Dynamic-mechanical thermal analysis (DMTA) displayed a slight increase in the stiffness by adding OLS up to 2.5 wt.%. However, at 5wt% OLS content the stiffness of the nanocomposites was below that of the unfilled hybrid resin. The glass transition temperature (Tg) did not change practically with the OLS type and content. Fracture mechanical tests were performed on compact tension (CT) specimens. The fracture toughness (Kc) increased slightly, while the fracture energy (Gc) markedly with increasing OLS content. Unexpectedly, TMDA proved to be a more suitable intercalant than OAE. The failure mode of the specimens was studied in a scanning electron microscope (SEM) and discussed. In addition, the water sorption behavior of the OLS modified VEUHs was determined and the diffusion coefficients (D) deduced.

Correlation of Vulcanization and Viscoelastic Properties of Nanocomposites Based on Natural Rubber and Different Nanofillers, with Molecular and Supramolecular Structure

2010 ◽  
Vol 83 (1) ◽  
pp. 16-34 ◽  
Author(s):  
Mithun Bhattacharya ◽  
Anil K. Bhowmick
Keyword(s):  
Natural Rubber ◽  
Rheological Properties ◽  
Supramolecular Structure ◽  
Carbon Nanofiber ◽  
Volume Fraction ◽  
Barrier Properties ◽  
Qualitative Description ◽  
Viscoelastic Parameters ◽  
Low Volume ◽  
And Performance

Abstract Elastomer nanocomposites reinforced with low volume fraction of nanofillers, such as nanoclays and carbon nanofibers, have long been known to possess significantly improved mechanical, thermal, dynamic mechanical, flame retardant, and barrier properties. The present work attempts to evaluate the effect of nanofillers (like modified and unmodified montmorillonite, sepiolite, carbon nanofiber, and carbon black) and their amount on vulcanization, as well as dynamic and rheological properties in the prevulcanization and postvulcanization stages. Upon using organomodified nanoclay, optimum cure time was reduced and cure rate index increased; whereas, in comparison, carbon nanofiber resulted in a slower cure. The influence of loading of some representative nanofillers on natural rubber was studied through qualitative description of critical dynamic viscoelastic parameters, which indicated the formation of supramolecular structure even at low volume fraction. The nanocomposite vulcanizates showed solidlike rheological behavior and upon implementation of dispersion techniques the activation energy of flow was reduced by around 60%. The knowledge of cure and rheological properties of the compounds, which evolves from the structure formation, can be utilized for assessing process optimization, cost reduction, and performance of the nanocomposites.

Recent Developments in Carbon Nanotube Sorting and Selective Growth

MRS Bulletin ◽  
2010 ◽  
Vol 35 (4) ◽  
pp. 315-321 ◽  
Author(s):  
Jie Liu ◽  
Mark C. Hersam
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
High Performance ◽  
Selective Growth ◽  
Synthetic Methods ◽  
Structure And Properties ◽  
Recent Developments ◽  
High Carrier ◽  
Optoelectronic Applications ◽  
Significant Effort

AbstractDue to their high carrier mobilities, electromigration resistance, and tailorable optical properties, carbon nanotubes are promising candidates for high-performance electronic and optoelectronic applications. However, traditional synthetic methods have lacked control over the structure and properties of carbon nanotubes. This polydispersity problem has confounded efforts to take carbon nanotubes from the research laboratory to the marketplace, especially for electronic and optoelectronic applications, where reliable and reproducible performance is paramount. In recent years, the research community has devoted significant effort to this issue, leading to substantial advances in the preparation of monodisperse carbon nanotube materials. This article highlights the most recent and promising developments from two perspectives: post-synthetic sorting and selective growth of carbon nanotubes of predetermined physical and electronic structure. These complementary approaches have yielded improved uniformity in carbon nanotube materials, resulting in impressive advances in carbon nanotube electronic and optoelectronic technology.

Synthesis and Characterization of High Performance Polymer Nanocomposite Using Carbon Nanotubes as Fillers

2013 ◽  
Author(s):  
N. Thangapandian ◽  
S. Balasivanandha Prabu ◽  
R. Paskaramoorthy
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
High Performance ◽  
Chemical Vapour ◽  
Fire Retardant ◽  
Wall Structure ◽  
Air Oxidation ◽  
Multiwalled Carbon ◽  
Uniform Dispersion ◽  
Sonication Technique

In this work, the chemical vapour deposition (CVD) method is used for the production of carbon nanotubes (CNTs). The catalyst, Fe/MgO, was prepared through sonication technique. It was heated to 600 °C for 6 hours and this was used as the template for growing the CNTs using acetylene as carbon precursor. The deposited CNTs were separated by acid treatment followed by air oxidation. The purified CNTs were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The CNTs were observed to have a multi-wall structure with the diameter in the range of 10–20 nm. These multiwalled carbon nanotubes (MWCNTs) were used as filler material in an epoxy matrix. Sonication technique was used to achieve uniform dispersion of CNTs within the matrix. The CNT/epoxy nanocomposite was cured at a temperature of 100 °C for 3 hours. Tensile strength, flexural strength, fire retardant properties and surface conductivity were studied. The results reveal that addition of MWCNTs to the epoxy promotes substantial improvement to the above mentioned properties.

scholarly journals Chemical Functionalization of Helical Carbon Nanotubes: Influence of Sonication Time and Concentrations of Sulfuric and Nitric Acids with 3 : 1 Mixing Ratio

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Sean R. Taklimi ◽  
Ali Ghazinezami ◽  
Davood Askari
Keyword(s):  
Carbon Nanotubes ◽  
Process Parameters ◽  
High Performance ◽  
Mixing Ratio ◽  
Sonication Time ◽  
Polymeric Nanocomposites ◽  
Chemical Functionalization ◽  
Helical Carbon Nanotubes ◽  
Uniform Dispersion ◽  
Dispersion Test

Carbon nanotubes (CNTs) with straight geometries have been widely studied for various engineering applications, and they are often treated or functionalized to improve their effectiveness, depending on their role and expected performance. However, helical configurations of CNTs (HCNTs) have not been sufficiently investigated, especially in their functionalized states for high-performance nanocomposite applications. The coil-shaped geometry of these HCNTs increases the mechanical entanglement of these nanotubes with a host resin system when they are used as reinforcements. This consequently has the potential to improve the mechanical, thermal, electrical, and magnetic properties of the polymeric matrix systems. A uniform dispersion of CNTs in the resin plays an important role in obtaining improved and consistent properties in the final nanocomposite part. To improve the homogeneous dispersion (individual suspension) of these nanotubes in the host resin and to enhance their interactions/bonds with the resin molecules, the surface of these nanotubes should be modified. This study investigates a sonication method for chemical functionalization of HCNTs using a mixture of sulfuric and nitric acids with 3 to 1 mixing ratio [3 : 1], and it evaluates the effects of acid concentrations and sonication time on the severity of the functionalization process. To evaluate the effectiveness of the process parameters, the functionalized HCNTs (FHCNTs) were examined using several characterization instruments and techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), visual dispersion test, and Raman spectroscopy. The characterization results confirmed that the changes in process parameters were mostly effective and the atomic structures of the functionalized HCNTs were successfully altered. All FHCNT samples demonstrated higher dispersion uniformity, increase in Raman ID/IG ratios, and changes in the FTIR spectra compared to the pristine HCNTs. Most of the FHCNTs had a reduction in crystallinity, which was consistent with our expectation that functionalization generates more defects on the surface structure of HCNTs, thus leading to a lower intensity of the graphitic peak. The largest reduction in crystallinity was seen for HCNTs treated with a 16 molarity acidic solution; therefore, the HCNTs that were treated with lower molarity acids could be used for further studies and explored for their effective applications in improving the mechanical, thermal, and electrical properties of polymeric nanocomposites.

An approach to the uniform dispersion of a high volume fraction of carbon nanotubes in aluminum powder

Carbon ◽  
2011 ◽  
Vol 49 (6) ◽  
pp. 1965-1971 ◽  
Author(s):  
Lin Jiang ◽  
Genlian Fan ◽  
Zhiqiang Li ◽  
Xizhou Kai ◽  
Di Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Aluminum Powder ◽  
Volume Fraction ◽  
High Volume ◽  
High Volume Fraction ◽  
Uniform Dispersion

scholarly journals Surface Alkylation of Cellulose Nanocrystals to Enhance Their Compatibility with Polylactide

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 178 ◽  
Author(s):  
Joo Hyung Lee ◽  
Sang Ho Park ◽  
Seong Hun Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Cellulose Nanocrystals ◽  
High Performance ◽  
Barrier Properties ◽  
Practical Application ◽  
Alkyl Groups ◽  
Uniform Dispersion ◽  
Solution Casting Method ◽  
Experimental Values

Effective surface alkylation of cellulose nanocrystals (CNCs) was developed using a nucleophilic substitution reaction with an alkyl bromide to convert hydrophilic groups on the CNCs into alkyl groups and the degree of substitution was quantitatively determined. The resultant alkylated CNCs exhibited improved dispersion in a nonpolar environment and increased hydrophobicity, compared with unmodified and acetylated CNCs. Polylactide (PLA) nanocomposites reinforced with unmodified and modified CNCs were prepared by a solution casting method and the effects of reinforcement on the thermal stability, mechanical properties, morphology, and barrier properties were investigated. In addition, modeling of the mechanical properties was evaluated to simulate the modulus of the PLA nanocomposites and results were compared with the experimental values. PLA nanocomposites reinforced with alkylated CNCs exhibited superior properties in terms of thermal stability, tensile strength, Young’s modulus, and barrier properties because of the uniform dispersion and strong interfacial adhesion between filler and matrix. This high performance and fully return-to-nature nanocomposite is expected to expand the utilization of CNCs from sustainable bioresources and the practical application of biodegradable plastics.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

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