Preparation and Characterization of High Performance LLDPE/Graphene Nanocomposites

2011 ◽  
Vol 410 ◽  
pp. 152-155 ◽  
Author(s):  
Tapas Kuila ◽  
Bong Joo Jung ◽  
Xiao Fei Yi ◽  
Joong Hee Lee
Keyword(s):  
High Performance ◽  
Barrier Properties ◽  
Functionalized Graphene ◽  
Transmission Electron Microscopy Analysis ◽  
Gas Barrier ◽  
Graphene Nanocomposites ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Mixing Method ◽  
Modified Graphene

The nanocomposites containing linear low density polyethylene (LLDPE) and dodecyl amine (DA) modified graphene (DA-G) as nanofiller have been prepared by solution-mixing method and characterized. Transmission electron microscopy analysis of the nanocomposites exhibits homogeneous dispersion of graphene in the LLDPE matrix. Thermal stability of the nanocomposites with 1 wt.% DA-G are superior as compared to neat LLDPE. Gas barrier properties of the nanocomposites are also much better than that of the neat LLPDE. Co-efficient of thermal expansion values of the nanocomposites decreases with the addition of functionalized graphene. Keywords: Functionalized graphene; UV-Vis spectra; Nanocomposites; Gas barrier property; Mechanical property

Barrier and biodegradable properties of corn starch-derived biopolymer film filled with nanoclay fillers

2016 ◽  
Vol 33 (3) ◽  
pp. 309-336 ◽  
Author(s):  
TP Mohan ◽  
Kay Devchand ◽  
K Kanny
Keyword(s):  
Water Absorption ◽  
Corn Starch ◽  
Barrier Properties ◽  
Mechanical Analysis ◽  
Oxygen Permeation ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Before And After ◽  
Electron Microscopy Analysis ◽  
Nanoclay Content

The objective of this work is to study the effect of nanoclay fillers on the biodegradation and barrier properties of corn starch polymer-based biofilm. Starch derived from corn plant source was used to prepare a biofilm by plasticization method. The barrier properties, namely, water absorption, moisture permeation, oxygen permeation and swelling of unfilled and nanoclay-filled corn starch biofilms were examined. The results indicate: ∼22% reduced water absorption, 40% reduced moisture uptake, 30% reduced oxygen permeation and 31% reduced swelling for 2–3 wt.% nanoclay-filled biofilm, when compared with unfilled biopolymer. The biodegradation result of unfilled and nanoclay-filled film series indicates that the nanoclay addition delays the biodegradation and is a function of nanoclay content in the film. The tensile, dynamic mechanical analysis and biodegradable studies were conducted on the biopolymers before and after water absorption, and the result shows that the nanoclay-filled biopolymer increased these properties when compared with unfilled biopolymer even after water absorption and is dependent on the nanocomposite structure and morphology as examined by X-ray diffraction and transmission electron microscopy analysis.

Mechanical and barrier properties of copolyester-nanoclay composites

2014 ◽  
Vol 34 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Turup P. Mohan ◽  
Krishnan Kanny
Keyword(s):  
Barrier Properties ◽  
Processing Parameters ◽  
Structural Examination ◽  
Melt Mixing ◽  
Gas Barrier ◽  
Clay Particles ◽  
Transmission Electron ◽  
Mixing Method ◽  
Modified Formula ◽  
Gas Barrier Properties

Abstract This paper examines the influence of nanoclay on the structure, thermal and mechanical and gas barrier properties of a polyethylene terephthalate (PET)-based copolyester using a new modified formula. The copolyester considered in this work consists of partially replaced acid and diol monomers in main chain PET polymers, namely, polyethylene glycol (PEG) and isophthalic acid monomers, i.e., PET-IP. Nanoclays were filled from 0–3 wt% in PET-IP using the melt mixing method. The structural examination of composites tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the distribution of nanolayers of clay particles in polymeric matrix. Up to 1 wt% nanoclay in PET-IP, an exfoliated structure resulted and above 1 wt% nanoclay an intercalated structure resulted. It was observed that 0.5 wt% nanoclay filled PET-IP resulted in improved nucleation characteristics and above 0.5 wt% nanoclay dramatically increased the gas transport (CO2, O2, N2 and water vapor), thermal and mechanical properties. The results also showed that the distribution of nanoclays affected the gas barrier properties of the polymer and can be controlled by processing parameters.

CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO

2011 ◽  
Vol 10 (01n02) ◽  
pp. 23-28
Author(s):  
RAVI BHATIA ◽  
V. PRASAD ◽  
M. REGHU
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
High Degree

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.

scholarly journals Thermodynamic Modelling and Microstructural Study of Z-Phase Formation in a Ta-Alloyed Martensitic Steel

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1332
Author(s):  
Florian Riedlsperger ◽  
Bernadette Gsellmann ◽  
Erwin Povoden-Karadeniz ◽  
Oriana Tassa ◽  
Susanna Matera ◽  
...  
Keyword(s):  
Special Focus ◽  
Scanning Calorimetry ◽  
Transmission Electron Microscopy Analysis ◽  
Computational Framework ◽  
Mobility Data ◽  
Interfacial Energies ◽  
Transmission Electron ◽  
Size Number ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

A thermokinetic computational framework for precipitate transformation simulations in Ta-containing martensitic Z-steels was developed, including Calphad thermodynamics, diffusion mobility data from the literature, and a kinetic parameter setup that considered precipitation sites, interfacial energies and dislocation density evolution. The thermodynamics of Ta-containing subsystems were assessed by atomic solubility data and enthalpies from the literature as well as from the experimental dissolution temperature of Ta-based Z-phase CrTaN obtained from differential scanning calorimetry. Accompanied by a comprehensive transmission electron microscopy analysis of the microstructure, thermokinetic precipitation simulations with a wide-ranging and well-documented set of input parameters were carried out in MatCalc for one sample alloy. A special focus was placed on modelling the transformation of MX into the Z-phase, which was driven by Cr diffusion. The simulation results showed excellent agreement with experimental data in regard to size, number density and chemical composition of the precipitates, showing the usability of the developed thermokinetic simulation framework.

Polyimide nanocomposites with functionalized graphene sheets

2017 ◽  
Vol 31 (6) ◽  
pp. 837-861 ◽  
Author(s):  
Jin-Hae Chang
Keyword(s):  
Electrical Conductivity ◽  
Filler Content ◽  
Coefficient Of Thermal Expansion ◽  
Barrier Properties ◽  
Decomposition Temperature ◽  
Graphene Sheets ◽  
Functionalized Graphene ◽  
Hybrid Films ◽  
Initial Decomposition Temperature ◽  
Transmission Electron Microscopy Analysis

Polyimide (PI) nanocomposites containing two different functionalized graphene sheets (FGSs) were synthesized, and their thermal properties, morphology, oxygen permeability, and electrical conductivity were compared. Hexadecylamine–graphene sheets and 4-amino- N-hexadecylbenzamide–graphene sheets were utilized. Hybrid films were obtained from blended solutions of PI and FGSs, with the filler content with respect to the PI varying from 0 wt% to 10 wt%. The differences in the properties of the PI matrix were then analyzed with respect to filler content. Transmission electron microscopy analysis confirmed that the two FGSs were dispersed homogeneously throughout the polymer matrix, although some FGS aggregates were also formed. Furthermore, it was observed that the addition of small amounts of FGS nanofiller was sufficient to improve the coefficient of thermal expansion, the gas barrier properties, and the electrical conductivity of the hybrid films. In contrast, the glass transition temperature and the initial decomposition temperature of the PI hybrid films continued to decrease with increasing FGS content.

scholarly journals Morphological changes and bioaccumulation in response to cadmium exposure in Morchella spongiola, a fungus with potential for detoxification

2021 ◽  
Author(s):  
Hongyan Xu ◽  
Jing Guo ◽  
Qing Meng ◽  
Zhanling Xie
Keyword(s):  
Electron Microscopy ◽  
Morphological Changes ◽  
Intracellular Accumulation ◽  
Tolerance Mechanism ◽  
Edible Fungi ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Micro Morphology

<i>Morchella</i> is a genus of edible fungi with strong resistance to Cd and the ability to accumulate it in the mycelium. However, the mechanisms conferring Cd resistance in <i>Morchella</i> are unknown. In the present study, morphological and physiological responses to Cd were evaluated in the mycelia of <i>Morchella spongiola</i>. Variations in hyphal micro-morphology including twisting, folding and kinking in mycelia exposed to different Cd concentrations (0.15, 0.9, 1.5, 2.4, 5.0 mg/L) were observed using scanning electron microscopy. Deposition of Cd precipitates on cell surfaces (at Cd concentrations > 2.4 mg/L) was shown by SEM-EDS. Transmission electron microscopy analysis of cells exposed to different concentrations of Cd revealed the loss of intracellular structures and the localization of Cd depositions inside/outside the cell. FTIR analysis showed that functional groups such as C=O, -OH, -NH and -CH could be responsible for Cd binding on the cell surface of <i>M. spongiola</i>. In addition, intracellular accumulation was observed in cultures at low Cd concentrations (< 0.9 mg/L), while extracellular adsorption occurred at higher concentrations. These results provide valuable information on the Cd tolerance mechanism in <i>M. spongiola</i> and constitute a robust foundation for further studies on fungal bioremediation strategies.

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