scholarly journals Entropic Effects in Polymer Nanocomposites

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 186 ◽  
Author(s):  
Xiaobin Dai ◽  
Cuiling Hou ◽  
Ziyang Xu ◽  
Ye Yang ◽  
Guolong Zhu ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Polymer Nanocomposite ◽  
Industrial Applications ◽  
Characteristic Parameters ◽  
Interparticle Interactions ◽  
Recent Advancement ◽  
The Matrix ◽  
Experimental Findings ◽  
Phase Behaviors ◽  
Entropic Effects

Polymer nanocomposite materials, consisting of a polymer matrix embedded with nanoscale fillers or additives that reinforce the inherent properties of the matrix polymer, play a key role in many industrial applications. Understanding of the relation between thermodynamic interactions and macroscopic morphologies of the composites allow for the optimization of design and mechanical processing. This review article summarizes the recent advancement in various aspects of entropic effects in polymer nanocomposites, and highlights molecular methods used to perform numerical simulations, morphologies and phase behaviors of polymer matrices and fillers, and characteristic parameters that significantly correlate with entropic interactions in polymer nanocomposites. Experimental findings and insight obtained from theories and simulations are combined to understand how the entropic effects are turned into effective interparticle interactions that can be harnessed for tailoring nanostructures of polymer nanocomposites.

scholarly journals Percolation analysis of the electrical conductive network in a polymer nanocomposite by nanorod functionalization

RSC Advances ◽  
2019 ◽  
Vol 9 (62) ◽  
pp. 36324-36333 ◽  
Author(s):  
Ruibin Ma ◽  
Guangyao Mu ◽  
Huan Zhang ◽  
Jun Liu ◽  
Yangyang Gao ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Polymer Nanocomposites ◽  
Polymer Nanocomposite ◽  
Conductive Network ◽  
Effective Strategy ◽  
Chemical Functionalization ◽  
The Matrix

Chemical functionalization of nanofillers is an effective strategy to benefit the formation of the conductive network in the matrix which can enhance the electrical conductivity of polymer nanocomposites (PNCs).

scholarly journals Magnetic Properties of Nanocomposites

2019 ◽  
Vol 9 (2) ◽  
pp. 212 ◽  
Author(s):  
Gabriele Barrera ◽  
Paola Tiberto ◽  
Paolo Allia ◽  
Barbara Bonelli ◽  
Serena Esposito ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Transition Metal ◽  
Polymer Nanocomposites ◽  
Information And Communication Technologies ◽  
Magnetic Behavior ◽  
Transition Metal Ions ◽  
Interparticle Interactions ◽  
Metal Compounds ◽  
The Matrix ◽  
Ceramic Nanocomposites

The magnetic properties of various families of nanocomposite materials containing nanoparticles of transition metals or transition-metal compounds are reviewed here. The investigated magnetic nanocomposites include materials produced either by dissolving a ferrofluid containing pre-formed nanoparticles of desired composition and size in a fluid resin submitted to subsequent curing treatment, or by generating the nanoparticles during the very synthesis of the embedding matrix. Two typical examples of these production methods are polymer nanocomposites and ceramic nanocomposites. The resulting magnetic properties turn out to be markedly different in these two classes of nanomaterials. The control of nanoparticle size, distribution, and aggregation degree is easier in polymer nanocomposites, where the interparticle interactions can either be minimized or exploited to create magnetic mesostructures characterized by anisotropic magnetic properties; the ensuing applications of polymer nanocomposites as sensors and in devices for Information and Communication Technologies (ICT) are highlighted. On the other hand, ceramic nanocomposites obtained from transition-metal loaded zeolite precursors exhibit a remarkably complex magnetic behavior originating from the simultaneous presence of zerovalent transition-metal nanoparticles and transition-metal ions dissolved in the matrix; the applications of these nanocomposites in biomedicine and for pollutant remediation are briefly discussed.

scholarly journals Recent Advances in the Synthesis of Polymer-Grafted Low-K and High-K Nanoparticles for Dielectric and Electronic Applications

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2942
Author(s):  
Bhausaheb V. Tawade ◽  
Ikeoluwa E. Apata ◽  
Nihar Pradhan ◽  
Alamgir Karim ◽  
Dharmaraj Raghavan
Keyword(s):  
Energy Density ◽  
Polymer Nanocomposites ◽  
High Performance ◽  
Breakdown Strength ◽  
Polymer Nanocomposite ◽  
High Energy ◽  
Polymer Chains ◽  
High Energy Density ◽  
Grafted Nanoparticles ◽  
Grafting From

The synthesis of polymer-grafted nanoparticles (PGNPs) or hairy nanoparticles (HNPs) by tethering of polymer chains to the surface of nanoparticles is an important technique to obtain nanostructured hybrid materials that have been widely used in the formulation of advanced polymer nanocomposites. Ceramic-based polymer nanocomposites integrate key attributes of polymer and ceramic nanomaterial to improve the dielectric properties such as breakdown strength, energy density and dielectric loss. This review describes the ”grafting from” and ”grafting to” approaches commonly adopted to graft polymer chains on NPs pertaining to nano-dielectrics. The article also covers various surface initiated controlled radical polymerization techniques, along with templated approaches for grafting of polymer chains onto SiO2, TiO2, BaTiO3, and Al2O3 nanomaterials. As a look towards applications, an outlook on high-performance polymer nanocomposite capacitors for the design of high energy density pulsed power thin-film capacitors is also presented.

scholarly journals A Review on Polymer Nanocomposites and Their Effective Applications in Membranes and Adsorbents for Water Treatment and Gas Separation

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 139
Author(s):  
Oluranti Agboola ◽  
Ojo Sunday Isaac Fayomi ◽  
Ayoola Ayodeji ◽  
Augustine Omoniyi Ayeni ◽  
Edith E. Alagbe ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Polymer Nanocomposites ◽  
Gas Separation ◽  
Rapid Growth ◽  
Dye Removal ◽  
Anthropogenic Activities ◽  
Polymer Nanocomposite ◽  
Population Increase ◽  
Nanocomposite Membranes

Globally, environmental challenges have been recognised as a matter of concern. Among these challenges are the reduced availability and quality of drinking water, and greenhouse gases that give rise to change in climate by entrapping heat, which result in respirational illness from smog and air pollution. Globally, the rate of demand for the use of freshwater has outgrown the rate of population increase; as the rapid growth in town and cities place a huge pressure on neighbouring water resources. Besides, the rapid growth in anthropogenic activities, such as the generation of energy and its conveyance, release carbon dioxide and other greenhouse gases, warming the planet. Polymer nanocomposite has played a significant role in finding solutions to current environmental problems. It has found interest due to its high potential for the reduction of gas emission, and elimination of pollutants, heavy metals, dyes, and oil in wastewater. The revolution of integrating developed novel nanomaterials such as nanoparticles, carbon nanotubes, nanofibers and activated carbon, in polymers, have instigated revitalizing and favourable inventive nanotechnologies for the treatment of wastewater and gas separation. This review discusses the effective employment of polymer nanocomposites for environmental utilizations. Polymer nanocomposite membranes for wastewater treatment and gas separation were reviewed together with their mechanisms. The use of polymer nanocomposites as an adsorbent for toxic metals ions removal and an adsorbent for dye removal were also discussed, together with the mechanism of the adsorption process. Patents in the utilization of innovative polymeric nanocomposite membranes for environmental utilizations were discussed.

Preschoolers’ imitation of sentential complement sentences: Does the nature of the matrix clause matter?

2021 ◽  
pp. 014272372110242
Author(s):  
Ian Morton ◽  
C. Melanie Schuele
Keyword(s):  
Language Development ◽  
Age Group ◽  
Matrix Clause ◽  
Developmental Progression ◽  
Main Effect ◽  
Dependent Variables ◽  
The Matrix ◽  
Group 3 ◽  
Sentence Imitation ◽  
Experimental Findings

Preschoolers’ earliest productions of sentential complement sentences have matrix clauses that are limited in form. Diessel proposed that matrix clauses in these early productions are propositionally empty fixed phrases that lack semantic and syntactic integration with the clausal complement. By 4 years of age, however, preschoolers produce sentential complement sentences with matrix clauses that are more varied. Diessel proposed that the matrix clauses in these later productions semantically and syntactically embed the complement clause. We refer to these matrix clauses as formulaic and true, respectively. Diessel’s hypothesis about the development of sentential complement sentences was based on an analysis of spontaneous language. The purpose of this study was to evaluate Diessel’s hypothesis with an experimental sentence imitation task wherein stimuli varied in the nature of the matrix clause. Thirty children with typical language development participated; 10 children in each age group (3-, 4-, and 5-year-olds) imitated 50 sentential complement sentences that included either a true or a formulaic matrix clause; the structure of the dependent clauses did not vary. Dependent variables were percent sentence imitation and percent matrix clause imitation. There was a significant main effect for matrix clause type on imitation of sentences and matrix clauses. There was also a significant main effect for age on imitation of sentences and matrix clauses. Significant matrix clause type-by-age interactions were such that percent sentence imitation and percent matrix clause imitation varied by age. Three- and 4-year-olds were less proficient than 5-year-olds on imitation of sentences with true matrix clauses and on imitations of true matrix clauses. Only 3- and 4-year-olds were less proficient imitating true matrix clauses than formulaic matrix clauses. Experimental findings support Diessel’s hypothesis that there is a developmental progression in the nature of preschoolers’ production of sentential complement sentences.

Magnetic polymer nanocomposite-supported Pd: an efficient and reusable catalyst for the Heck and Suzuki reactions in water

2015 ◽  
Vol 39 (3) ◽  
pp. 2052-2059 ◽  
Author(s):  
Dongfang Wang ◽  
Wendong Liu ◽  
Fengling Bian ◽  
Wei Yu
Keyword(s):  
Polymer Nanocomposites ◽  
Polymer Nanocomposite ◽  
Recyclable Catalyst ◽  
Water Phase ◽  
Reusable Catalyst ◽  
Suzuki Reactions ◽  
Supported Pd

Pd supported on magnetic polymer nanocomposites serves as an efficient and recyclable catalyst for the water-phase Heck and Suzuki reactions.

A study on tribological behaviour and analysis of ZnO reinforced AA6061 matrix composites fabricated by stir casting route

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sakthi Sadhasivam RM ◽  
Ramanathan K. ◽  
Bhuvaneswari B.V. ◽  
Raja R.
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Stir Casting ◽  
Industrial Applications ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Content Type ◽  
Zno Particles ◽  
The Matrix

Purpose The most promising replacements for the industrial applications are particle reinforced metal matrix composites because of their good and combined mechanical properties. Currently, the need of matrix materials for industrial applications is widely satisfied by aluminium alloys. The purpose of this paper is to evaluate the tribological behaviour of the zinc oxide (ZnO) particles reinforced AA6061 composites prepared by stir casting route. Design/methodology/approach In this study, AA6061 aluminium alloy matrix reinforced with varying weight percentages (3%, 4.5% and 6%) of ZnO particles, including monolithic AA6061 alloy samples, is cast by the most economical fabrication method, called stir casting. The prepared sample was subjected to X-ray photoelectron spectroscopy (XPS) analysis, experimental density measurement by Archimedian principle and theoretical density by rule of mixture and hardness test to investigate mechanical property. The dry sliding wear behaviour of the composites was investigated using pin-on-disc tribometer with various applied loads of 15 and 20 N, with constant sliding velocity and distance. The wear rate, coefficient of friction (COF) and worn surfaces of the composite specimens and their effects were also investigated in this work. Findings XPS results confirm the homogeneous distribution of ZnO microparticles in the Al matrix. The Vickers hardness result reveals that higher ZnO reinforced (6%) sample have 34.4% higher values of HV than the monolithic aluminium sample. The sliding wear tests similarly show that increasing the weight percentage of ZnO particles leads to a reduced wear rate and COF of 30.01% and 26.32% lower than unreinforced alloy for 15 N and 36.35% and 25% for 20 N applied load. From the worn surface morphological studies, it was evidently noticed that ZnO particles dispersed throughout the matrix and it had strong bonding between the reinforcement and the matrix, which significantly reduced the plastic deformation of the surfaces. Originality/value The uniqueness of this work is to use the reinforcement of ZnO particles with AA6061 matrix and preparing by stir casting route and to study and analyse the physical, hardness and tribological behaviour of the composite materials.

ADDITIVE MANUFACTURING OF HIGH-LOADING POLYMER NANOCOMPOSITES WITH MULTISCALE ALIGNMENT

2021 ◽  
Author(s):  
SOYEON PARK ◽  
KUN (KELVIN) FU
Keyword(s):  
Additive Manufacturing ◽  
Polymer Nanocomposites ◽  
High Performance ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
High Productivity ◽  
Macro Scale ◽  
The Matrix ◽  
Multiscale Structures ◽  
Printing Direction

Polymer nanocomposites have advantages in mechanical, electrical, and optical properties compared to individual components. These unique properties of the nanocomposites have attracted attention in many applications, including electronics, robotics, biomedical fields, automotive industries. To achieve their high performance, it is crucial to control the orientation of nanomaterials within the polymer matrix. For example, the electric conductivity will be maximized in the ordered direction of conductive nanomaterials such as graphene and carbon nanotubes (CNTs). Conventional fabrication methods are commonly used to obtain polymer nanocomposites with the controlled alignment of nanomaterials using electric or magnetic fields, fluid flow, and shear forces. Such approaches may be complex in preparing a manufacturing system, have low fabrication rate, and even limited structure scalability and complexity required for customized functional products. Recently, additive manufacturing (AM), also called 3D printing, has been developed as a major fabrication technology for nanocomposites with aligned reinforcements. AM has the ability to control the orientation of nanoparticles and offers a great way to produce the composites with cost-efficiency, high productivity, scalability, and design flexibility. Herein, we propose a manufacturing process using AM for the architected structure of polymer nanocomposites with oriented nanomaterials using a polylactic acid polymer as the matrix and graphite and CNTs as fillers. AM can achieve the aligned orientation of the nanofillers along the printing direction. Thus, it enables the fabrication of multifunctional nanocomposites with complex shapes and higher precision, from micron to macro scale. This method will offer great opportunities in the advanced applications that require complex multiscale structures such as energy storage devices (e.g., batteries and supercapacitors) and structural electronic devices (e.g., circuits and sensors).

Retrogression and Re-aging Heat Treatment: AA7XXX Aluminum Alloys

2019 ◽  
Author(s):  
V. Anil Kumar ◽  
S. Arjun ◽  
R.K. Gupta ◽  
P.V. Venkitakrishnan
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Industrial Applications ◽  
Age Hardening ◽  
Large Cross Section ◽  
Structural Applications ◽  
The Matrix ◽  
Peak Aged ◽  
Aged Temper ◽  
Short Time

Retrogression and re-aging (RRA) treatment was introduced to increase the stress corrosion cracking (SCC) resistance while retaining the strength attainable in T6 (peak aged) temper. Retrogression is a short-term heat treatment at an elevated temperature wherein a partial dissolution of metastable precipitates occurs, which are responsible for the hardening. During the next step, the material is re-aged in the regime of typical age hardening parameters to restore the strength with improved ductility. Response of RRA treatment has been reported on AA7XXX series Aluminum alloys such as AA7075, AA7050, AA7150, AA7049, and AA7010. Studies have been done on the effect of RRA on microstructure, mechanical properties such as tensile and hardness, corrosion, exfoliation corrosion, and SCC resistance by various researchers. The key characteristic of RRA is retrogression, which makes the re-precipitation in the matrix and coarsening of grain boundary precipitates such as MgZn2, η′. The retrogression treatment however requires high temperature and a short time, which limits the industrial application of RRA, especially in the heat treatment of the components with large cross section, due to the inherent thermal conductivity limitations. Hence, further work needs to be done in this area to apply this specialized heat treatment for industrial applications. This article brings out a comprehension of the changes in microstructure, tensile properties, and corrosion resistance of the various commonly used AA7XXX Aluminum alloys in structural applications with RRA heat treatment. The future scope of the work in RRA heat treatment is also discussed in this article.

scholarly journals Micro Hardness and Erosive Wear Behavior of Tungsten Carbide Filled Epoxy Polymer Nano Composites

2020 ◽  
Vol 5 (3) ◽  
pp. 405-415
Author(s):  
M. Kameswara Reddy ◽  
V. Suresh Babu ◽  
K. V. Sai Srinadh
Keyword(s):  
Tungsten Carbide ◽  
Polymer Nanocomposites ◽  
Adhesive Bonding ◽  
Epoxy Polymer ◽  
Wear Behavior ◽  
Erosive Wear ◽  
Nano Composites ◽  
Erosion Wear ◽  
Wear Properties ◽  
The Matrix

The present work studies the tribological performance of Tungsten Carbide (WC) nanoparticles reinforced epoxy polymer nanocomposites. Polymer nanocomposites are prepared by hand lay-up method. Erosive wear and hardness tests were conducted to examine the physical and wear properties of epoxy/WC nanocomposites. Addition of WC nanoparticles led to significant reduction in erosion rate. In addition to that, incorporation of WC nanoparticles enhanced the hardness of epoxy nano composites. At 2% weight of WC nano filler, nanocomposites showed better performance in erosion wear properties and also in hardness. While at 3wt% of WC filler, least performance in hardness was caused by the weak adhesive bonding between the matrix and filler. The nature of erosion wear behavior was observed. Finally worn surfaces of nanocomposites were inspected using a “scanning electron microscope (SEM)”.

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