scholarly journals Polymer Nanocomposites with Different Types of Nanofiller

2019 ◽  
Author(s):  
Amanda Dantas de Oliveira ◽  
Cesar Augusto Gonçalves Beatrice
Keyword(s):  
Polymer Nanocomposites ◽  
Different Types

scholarly journals Synthesis and Characterization of Clay Polymer Nanocomposites of P(4VP-co-AAm) and Their Application for the Removal of Atrazine

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 721 ◽  
Author(s):  
Jorge A. Ramírez-Gómez ◽  
Javier Illescas ◽  
María del Carmen Díaz-Nava ◽  
Claudia Muro-Urista ◽  
Sonia Martínez-Gallegos ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Nanocomposite Materials ◽  
Synthesis And Characterization ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
Numerous Species ◽  
X Ray ◽  
Different Types ◽  
Synthesized Materials

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ.

scholarly journals EFFECTIVENESS OF USE OF NANO FILLERS OF DIFFERENT TYPES IN POLYMERIC COMPOSITES

2020 ◽  
Vol 63 (4) ◽  
pp. 81-85
Author(s):  
Vladimir Z. Aloyev ◽  
Zaira M. Zhirikova ◽  
Memunat A. Tarchokova
Keyword(s):  
Fractal Dimension ◽  
Polymer Nanocomposites ◽  
Maximum Degree ◽  
Volume Fraction ◽  
Relative Proportion ◽  
Relative Volume ◽  
Theoretical Evaluation ◽  
Relative Volume Fraction ◽  
Different Types ◽  
Degree Of Filling

The paper provides a theoretical analysis of the effectiveness of using different types of nanofillers to produce high-strength polymer composites. Three basic types of nanoscale inorganic nanofillers were selected: dispersed nanoparticles (0D-nanofillers), carbon nanotubes and nanofibers (1D-nanofillers), and organoclay, graphene, etc. (2D-fillers). The relative modulus of elasticity, i.e. the degree of amplification, is used as the main criterion for the effectiveness of nanofillers. Within the framework of the percolation model, the amplification levels of nanocomposites for different types of nanofillers are determined depending on the relative volume fraction of nanofillers and interfacial regions. It is shown that interfacial regions in polymer nanocomposites are treated as a reinforcing element of the nanocomposite structure. To describe the surface structure of nanofiller particles, an effective value of the fractal dimension is used, which serves as a determining factor for the relative proportion of interfacial regions. At a condition that the fractal dimension of the structural framework of nanofiller particles cannot exceed the fractal dimension of the enclosing Euclidean space, the relative proportion of interfacial regions and, through it, the maximum degree of filling for the types of nanofillers under consideration are determined. The results of the theoretical evaluation of the maximum limit value of the fractal dimension of nanofiller particles carried out in this work show that the formation of a bulk frame of particles is possible only for anisotropic nanofillers, and dispersed particles form chains that do not change the structure of the polymer matrix in comparison with the matrix polymer. It is also found that for each type of nanofiller, there is a limit maximum degree of filling, which ultimately determines the limit maximum degree of amplification of the nanocomposite. These results allow us to conclude that the most effective for creating structural polymer nanocomposites is a dispersed nanofiller.

scholarly journals DC Conductivity of Polymer Nanocomposites for Different Types and Amount of Nanofiller

2013 ◽  
Vol 5 (2) ◽  
pp. 217-225 ◽  
Author(s):  
Nor Akmal Mohd Jamail ◽  
◽  
Mohamed Afendi Mohamed Piah ◽  
Nor Asiah Muhamad ◽  
R A Zainir ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Dc Conductivity ◽  
Different Types

scholarly journals Properties of Graphene-Related Materials Controlling the Thermal Conductivity of Their Polymer Nanocomposites

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2167
Author(s):  
Samuele Colonna ◽  
Daniele Battegazzore ◽  
Matteo Eleuteri ◽  
Rossella Arrigo ◽  
Alberto Fina
Keyword(s):  
Thermal Conductivity ◽  
Polymer Nanocomposites ◽  
Surface Functionalization ◽  
Lateral Size ◽  
Large Scatter ◽  
Preparation Methods ◽  
Conductivity Enhancement ◽  
Melt Polymerization ◽  
Wide Range ◽  
Different Types

Different types of graphene-related materials (GRM) are industrially available and have been exploited for thermal conductivity enhancement in polymers. These include materials with very different features, in terms of thickness, lateral size and composition, especially concerning the oxygen to carbon ratio and the possible presence of surface functionalization. Due to the variability of GRM properties, the differences in polymer nanocomposites preparation methods and the microstructures obtained, a large scatter of thermal conductivity performance is found in literature. However, detailed correlations between GRM-based nanocomposites features, including nanoplatelets thickness and size, defectiveness, composition and dispersion, with their thermal conductivity remain mostly undefined. In the present paper, the thermal conductivity of GRM-based polymer nanocomposites, prepared by melt polymerization of cyclic polybutylene terephtalate oligomers and exploiting 13 different GRM grades, was investigated. The selected GRM, covering a wide range of specific surface area, size and defectiveness, secure a sound basis for the understanding of the effect of GRM properties on the thermal conductivity of their relevant polymer nanocomposites. Indeed, the obtained thermal conductivity appeares to depend on the interplay between the above GRM feature. In particular, the combination of low GRM defectiveness and high filler percolation density was found to maximize the thermal conductivity of nanocomposites.

scholarly journals Effect of Nanofillers on Tribological Properties of Polymer Nanocomposites: A Review on Recent Development

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2867
Author(s):  
Jia Xin Chan ◽  
Joon Fatt Wong ◽  
Michal Petrů ◽  
Azman Hassan ◽  
Umar Nirmal ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Tribological Properties ◽  
Film Formation ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Research Field ◽  
Future Research ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Different Types ◽  
Silicon Based

Polymer nanocomposites with enhanced performances are becoming a trend in the current research field, overcoming the limitations of bulk polymer and meeting the demands of market and society in tribological applications. Polytetrafluoroethylene, poly(ether ether ketone) and ultrahigh molecular weight polyethylene are the most popular polymers in recent research on tribology. Current work comprehensively reviews recent advancements of polymer nanocomposites in tribology. The influence of different types of nanofiller, such as carbon-based nanofiller, silicon-based nanofiller, metal oxide nanofiller and hybrid nanofiller, on the tribological performance of thermoplastic and thermoset nanocomposites is discussed. Since the tribological properties of polymer nanocomposites are not intrinsic but are dependent on sliding conditions, direct comparison between different types of nanofiller or the same nanofiller of different morphologies and structures is not feasible. Friction and wear rate are normalized to indicate relative improvement by different fillers. Emphasis is given to the effect of nanofiller content and surface modification of nanofillers on friction, wear resistance, wear mechanism and transfer film formation of its nanocomposites. Limitations from the previous works are addressed and future research on tribology of polymer nanocomposites is proposed.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj> 0 for eachj> 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

Differentiating between different forms of moral obligations

2020 ◽  
Vol 43 ◽  
Author(s):  
Rajen A. Anderson ◽  
Benjamin C. Ruisch ◽  
David A. Pizarro
Keyword(s):  
Moral Character ◽  
Moral Obligations ◽  
Different Types

Abstract We argue that Tomasello's account overlooks important psychological distinctions between how humans judge different types of moral obligations, such as prescriptive obligations (i.e., what one should do) and proscriptive obligations (i.e., what one should not do). Specifically, evaluating these different types of obligations rests on different psychological inputs and has distinct downstream consequences for judgments of moral character.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

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