Kinetics of High Density Functional Polymer Nanocomposite formation by Tuning Enthalpic and Entropic Barriers

Soft Matter ◽  
2022 ◽  
Author(s):  
Aparna Swain ◽  
Nimmi A. Das ◽  
Sivasurender Chandran ◽  
Jaydeep Kumar Basu

High density functional polymer nanocomposites (PNCs) with high degree of dispersion have recently emerged as novel materials for various thermo-mechanical, optical and electrical applications. The key challenge is to attain...

Author(s):  
R. Namdeo ◽  
◽  
S. Tiwari ◽  
S. Manepatil ◽  
◽  
...  

Ethylene-co-vinyl acetate (EVA), high density polyethylene (HDPE) and their blends are being used in many engineering applications. In this work, an attempt was made to extend the conventional uses of EVA/HDPE blended polymer nanocomposites by laser treating their surface to automobile, aircraft, and similar industries, where tribological properties played an important role. Effects of laser irradiation on adhesive tribo-performances of maleic anhydride grafted polyethylene (MA-g-PE: 2phr) modified ethylene-co-vinyl acetate/high density polyethylene (EVA/HDPE: 70/30 wt. %) organ modified montmorillonite (OMMT: 4phr) blended polymer nanocomposite have been investigated. EVA/HDPE/MA-g-PE/OMMT polymer nanocomposite was irradiated by Ytterbium laser system (YSL-2000) at various scan speeds and power densities. As per ASTM G99 standard, tribo-performance attributes coefficient of friction and specific wear rate were evaluated using pin-on-disc machine against rotating EN31 steel disc of 60 HRC at different loads and speeds. Wear mechanisms of worn surfaces were analyzed using scanning electron microscopy (SEM) images. It was observed that coefficient of friction and specific wear rate were significantly affected by power density and load, while sliding distance and scan speed have marginal effects.


Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2942
Author(s):  
Bhausaheb V. Tawade ◽  
Ikeoluwa E. Apata ◽  
Nihar Pradhan ◽  
Alamgir Karim ◽  
Dharmaraj Raghavan

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.


Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 139
Author(s):  
Oluranti Agboola ◽  
Ojo Sunday Isaac Fayomi ◽  
Ayoola Ayodeji ◽  
Augustine Omoniyi Ayeni ◽  
Edith E. Alagbe ◽  
...  

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.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2560
Author(s):  
Jianwen Meng ◽  
Yong Pan ◽  
Fan Yang ◽  
Yanjun Wang ◽  
Zhongyu Zheng ◽  
...  

The thermal stability and decomposition kinetics analysis of 1-alkyl-2,3-dimethylimidazole nitrate ionic liquids with different alkyl chains (ethyl, butyl, hexyl, octyl and decyl) were investigated by using isothermal and nonisothermal thermogravimetric analysis combined with thermoanalytical kinetics calculations (Kissinger, Friedman and Flynn-Wall-Ozawa) and density functional theory (DFT) calculations. Isothermal experiments were performed in a nitrogen atmosphere at 240, 250, 260 and 270 °C. In addition, the nonisothermal experiments were carried out in nitrogen and air atmospheres from 30 to 600 °C with heating rates of 5, 10, 15, 20 and 25 °C/min. The results of two heating modes, three activation energy calculations and density functional theory calculations consistently showed that the thermal stability of 1-alkyl-2,3-dimethylimidazolium nitrate ionic liquids decreases with the increasing length of the alkyl chain of the substituent on the cation, and then the thermal hazard increases. This study could provide some guidance for the safety design and use of imidazolium nitrate ionic liquids for engineering.


2015 ◽  
Vol 39 (3) ◽  
pp. 2052-2059 ◽  
Author(s):  
Dongfang Wang ◽  
Wendong Liu ◽  
Fengling Bian ◽  
Wei Yu

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


Author(s):  
Rodrigo E. Teixeira ◽  
Richard S. Graham

The visco-elastic properties of entangled polymer liquids arise from molecular-scale topological interactions and stochastic fluctuations under flow. Here, the evolutions of individual entangled polymers were observed in rheologically relevant shear flow histories. We uncover a high degree of molecular individualism and broad conformational distributions resulting from incessant stretch-collapse cycles. The data and insights of the present study may lead to improved molecular-level models and constitutive equations. These tools, in turn, may enable the rational design of novel materials with properties tailored to accomplish specific tasks such as high-pressure vessels and piping with greater safety margins and cost-effectiveness.


2013 ◽  
Vol 47 (3) ◽  
pp. 875-887 ◽  
Author(s):  
Michael J. A. Hore ◽  
Russell J. Composto

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