Search results for "NANOCOMPOSITE"
showing 10 items of 641 documents
Incorporation of Mn12single molecule magnets into mesoporous silica
2003
The incorporation of four Mn12 derivatives, namely [Mn12O12(O2CR)16(H2O)4] (R = CH3 (1), CH3CH2 (2), C6H5 (3), C6F5 (4)), into the hexagonal channels of the MCM-41 mesoporous silica has been studied. Only the smallest clusters 1 and 2, i.e. those with compatible size with the pores of MCM-41, could enter into the mesoporous silica. Powder X-ray diffraction analysis, HRTEM images and N2 adsorption–desorption isotherm experiments show that the well-ordered hexagonal structure of MCM-41 is preserved and that the Mn12 clusters are inside the pores. The magnetic properties of the MCM-41/2b nanocomposite material obtained in CH2Cl2 indicate that the structure of the cluster is maintained after in…
Morphology Modification of Polyethylene/Clay Nanocomposite Samples under Convergent Flow
2009
The morphology of PE/CL nanocomposite samples subjected to convergent flows is studied. Elongational flow – the typical flow involved in spinning and film-blowing processing operations – significantly increases with the reduction of the capillary diameter. The values of the convergent extensional stress (calculated by Cogswell's formula) for the PE/CL systems, for all the adopted capillary geometries, are greater than the calculated values for pure polyethylene. The applied convergent flow, at the entrance of the capillary, is able to change the clay morphology and consequently the final material properties on the PE/CL system with limited affinity between the matrix and organo-modified cla…
Compatibilized Polyamide 6/Polyethylene Blends Clay Nanocomposites: Effect of the Degradation and Stabilization of the Clay Modifier
2008
Abstract Blends of polyamide 6 (PA6) and high-density polyethylene (HDPE) were compatibilized using an already investigated method and a sample of Cloisite 15A, a montmorillonite modified with ammonium quaternary salts was added. The blends were prepared in a twin screw extruder and characterized from a morphological, rheological and mechanical point of view. The results indicated that, despite a good morphology achieved in the filled blends and a moderate intercalation of the clay, the mechanical properties are far from being good, especially the ultimate properties. In order to investigate the possible influence of the inhibition of the crystallization and of the degradation of the organi…
CsPbX3/SiOx (X = Cl, Br, I) monoliths prepared via a novel sol-gel route starting from Cs4PbX6 nanocrystals
2019
We developed a facile synthesis of nanocomposite powders of CsPbX3 nanocrystals (NCs) embedded in silica. The synthesis starts from colloidal Cs4PbX6 NCs that are mixed with tetraethyl orthosilicate in the presence of nitric acid, which triggers the sol-gel reaction yielding the formation of SiOx and the conversion of starting NCs into CsPbX3 ones. The overall reaction delivers CsPbX3 NCs encased in a silica matrix. The resulting CsPbX3/SiOx nano-composite powders exhibited enhanced moisture and thermal stability in air. Also, when mixing different CsPbX3/SiOx samples having diverse anion compositions, no interparticle anion exchange processes were observed, which is a further indication th…
Scalable manufacturing of fibrous nanocomposites for multifunctional liquid sensing
2021
This research is supported by the Advanced Manufacturing Program (No. 1927623) from the National Science Foundation and by the McIntire-Stennis Cooperative Forestry Research Program (No. 1020630) from the USDA National Institute of Food and Agriculture. The authors also thank WestRock Paper Company for donated the wood pulp used in this research. Open access funding is enabled and organized by CERN. Cellulose-based paper electronics is an attractive technology to meet the growing demands for naturally abundant, biocompatible, biodegradable, flexible, inexpensive, lightweight and highly miniaturizable sensory materials. The price reduction of industrial carbon nanotube (CNT) grades offers op…
Aggregation-induced heterogeneities in the emission of upconverting nanoparticles at the submicron scale unfolded by hyperspectral microscopy
2018
Transparent upconverting hybrid nanocomposites are exciting materials for advanced applications such as 3D displays, nanosensors, solar energy converters, and fluorescence biomarkers. This work presents a simple strategy to disperse upconverting b-NaYF4:Yb3+/Er3+ or Tm3+ nanoparticles into low cost, widely used and easy-to-process polydimethylsiloxane (PDMS)-based organic–inorganic hybrids. The upconverting hybrids were shaped as monoliths, films or powders displaying in the whole volume Tm3+ or Er3+ emissions (in the violet/blue and green/red spectral regions, respectively). For the first time, hyperspectral microscopy allows the identification at the submicron scale of differences in the …
Synthesis and Properties of Amine-Cured Epoxy/Organophilic Layered Silicate Nanocomposites
2009
Epoxy-layered silicate composites have been prepared by dispersing an organically modified montmorillonite (Nanofil 919) in an epoxy resin and curing in the presence of an aromatic hardener. Dispersion of the layered silicate within the epoxy matrix was verified using X-ray diffraction and transmission electron microscopy revealing that interaction improves upon organic silicate modification. Flexural properties and toughness increase with the organic silicate loading whereas glass transition temperature decreases and thermal stability remains practically unmodified.
Real time polymer nanocomposites-based physical nanosensors: theory and modeling.
2017
Functionalized carbon nanotubes and graphene nanoribbons nanostructures, serving as the basis for the creation of physical pressure and temperature nanosensors, are considered as tools for ecological monitoring and medical applications. Fragments of nanocarbon inclusions with different morphologies, presenting a disordered system, are regarded as models for nanocomposite materials based on carbon nanoсluster suspension in dielectric polymer environments (e.g., epoxy resins). We have formulated the approach of conductivity calculations for carbon-based polymer nanocomposites using the effective media cluster approach, disordered systems theory and conductivity mechanisms analysis, and obtain…
Novel non-destructive evaluation technique for the detection of poor dispersion of carbon nanotubes in nanocomposites
2019
Abstract A wide use of advanced carbon nanotube polymer composites can be boosted by new non-destructive evaluation (NDE) techniques that can test the quality of the products to ensure that their specifications are met. It is well known in literature that the parameter that far more than others can affect the enhancing capabilities of the carbon nanotubes is their dispersion. Here we have presented a novel NDE technique based on infrared thermography able to evaluate the dispersion of the added nanoparticles in polymer nanocomposites. The NDE technique was used to compare pairs of samples whose difference is represented only by the level of dispersion. It was found a significant difference …
Ag and Au/DNQ-novolac nanocomposites patternable by ultraviolet lithography: a fast route to plasmonic sensor microfabrication
2010
In this work we report on a method to synthesize Ag–Au nanoparticles/polymer nanocomposite patterns by UV lithography. The photoresists are based on DNQ-novolac as the polymer matrix, and Ag(I) and Au(III) salts as the nanoparticle precursors. After UV lithography, silver and gold nanoparticles are in situ synthesized inside the polymer patterns during a post bake. The resulting structured nanocomposite shows a characteristic absorbance spectrum related to the plasmon frequency of the synthesized noble metal NPs. This method represents a fast, simple and low-cost approach to the formation of extended polymer patterns with embedded silver or gold NPs. Moreover, it is a mechanism to position …