scholarly journals Enhancing the Thermo-Mechanical Property of Polymer by Weaving and Mixing High Length–Diameter Ratio Filler

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1255 ◽  
Author(s):  
Bo Zhang ◽  
Yunmin Liang ◽  
Biwei Liu ◽  
Wei Liu ◽  
Zhichun Liu

Improving thermo-mechanical characteristics of polymers can efficiently promote their applications in heat exchangers and thermal management. However, a feasible way to enhance the thermo-mechanical property of bulk polymers at low filler content still remains to be explored. Here, we propose mixing high length-diameter ratio filler such as carbon nanotube (CNT), boron nitride (BN) nanotube, and copper (Cu) nanowire, in the woven polymer matrix to meet the purpose. Through molecular dynamics (MD) simulation, the thermal properties of three woven polymers including woven polyethylene (PE), woven poly (p-phenylene) (PPP), and woven polyacetylene (PA) are investigated. Besides, using woven PE as a polymer matrix, three polymer nanocomposites, namely PE-CNT, PE-BN, and PE-Cu, are constructed by mixing CNT, BN nanotube, and Cu nanowire respectively, whose thermo-mechanical characteristics are compared via MD simulation. Morphology and phonons spectra analysis are conducted to reveal the underlying mechanisms. Furthermore, impacts of electron-phonon coupling and electrical field on the thermal conductivity of PE-Cu are uncovered via two temperature model MD simulation. Classical theoretical models are modified to predict the effects of filler and matrix on the thermal conductivity of polymer nanocomposites. This work can provide useful guidelines for designing thermally conductive bulk polymers and polymer nanocomposites.

Nanoscale ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 6934-6943
Author(s):  
Haifei Zhan ◽  
Ying Zhou ◽  
Gang Zhang ◽  
Jihong Zhu ◽  
Weihong Zhang ◽  
...  

Polymer nanocomposites with regularly aligned and evenly distributed carbon nanothreads exhibit better thermal conductivity than their counterparts with randomly dispersed nanofillers or nanofillers with functional groups.


CrystEngComm ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 1657-1662
Author(s):  
Na Zhang ◽  
Yuqing Yin ◽  
Jian Zhang ◽  
Tao Wang ◽  
Siyuan Wang ◽  
...  

Lu2O3 crystals have attracted intense attention due to their great potential in the field of high power solid-state lasers.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 541 ◽  
Author(s):  
Albert J. Power ◽  
Ioannis N. Remediakis ◽  
Vagelis Harmandaris

Metal nanoparticles are used to modify/enhance the properties of a polymer matrix for a broad range of applications in bio-nanotechnology. Here, we study the properties of polymer/gold nanoparticle (NP) nanocomposites through atomistic molecular dynamics, MD, simulations. We probe the structural, conformational and dynamical properties of polymer chains at the vicinity of a gold (Au) NP and a functionalized (core/shell) Au NP, and compare them against the behavior of bulk polyethylene (PE). The bare Au NPs were constructed via a systematic methodology starting from ab-initio calculations and an atomistic Wulff construction algorithm resulting in the crystal shape with the minimum surface energy. For the functionalized NPs the interactions between gold atoms and chemically adsorbed functional groups change their shape. As a model polymer matrix we consider polyethylene of different molecular lengths, from the oligomer to unentangled Rouse like systems. The PE/Au interaction is parametrized via DFT calculations. By computing the different properties the concept of the interface, and the interphase as well, in polymer nanocomposites with metal NPs are critically examined. Results concerning polymer density profiles, bond order parameter, segmental and terminal dynamics show clearly that the size of the interface/interphase, depends on the actual property under study. In addition, the anchored polymeric chains change the behavior/properties, and especially the chain density profile and the dynamics, of the polymer chain at the vicinity of the Au NP.


2021 ◽  
Vol 318 ◽  
pp. 39-47
Author(s):  
Ahli K.D. Willie ◽  
Hong Tao Zhao ◽  
M. Annor-Nyarko

In this work, molecular dynamics (MD) simulation was utilized in relation to access the thermal conductivity of UO2, PuO2 and (U, Pu)O2 in temperature range of 500–3000 K. Diffusion study on mixed oxide (MOX) was also performed to assess the effect of radiation damage by heavy ions at burnup temperatures. Analysis of the lattice thermal conductivity of irradiated MOX to its microstructure was carried out to enhance the irradiation defects with how high burnup hinders fuel properties and its pellet-cladding interaction. Fission gas diffusion as determined was mainly modelled by main diffusion coefficient. Degradation of diffusivity is predicted in MOX as composition deviate from the pure end members. The concentration of residual anion defects is considerably higher than that of cations in all oxides. Depending on the diffusion behavior of the fuel lattice, there was decrease in the ratio of anion to cation defects with increasing temperature. Besides, the modern mixed oxide fuel releases fission gas compared to that of UO2 fuel at moderate burnups.


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