Journal ArticleDOI
On thermal conductivity of micro- and nanocellular polymer foams
Sriharsha S. Sundarram,Wei Li +1 more
TLDR
In this article, a wide range of pore sizes from 1 nm to 1 mm were studied in conjunction with the porosity effect using finite element analysis and molecular dynamics simulation methods.Abstract:
Many theoretical and empirical models exist to predict the effective thermal conductivity of polymer foams. However, most of the models only consider the effect of porosity, while the pore size effect is ignored. The objective of this study is to understand the effect of pore size on the thermal conductivity of polymer foams, especially when it reduces to the micro and nanometer scales. A wide range of pore sizes from 1 nm to 1 mm were studied in conjunction with the porosity effect using finite element analysis and molecular dynamics simulation methods. Experimental data was used to validate the modeling result. It is shown that the pore size has significant effect on thermal conductivity, even for microcellular and conventional foams. The contribution of heat conduction through air is negligible when pore size is reduced to the micrometer scale. The extremely low thermal conductivity of nanofoams is attributed to extensive diffusive scattering of heat carriers in the solid phase of polymer matrix, instead of air. This study provides quantitative understanding of the pore size effect on thermal conductivity of polymer foams. It is also shown that polyetherimide (PEI) nanofoams could have a thermal conductivity as low as 0.015 W/m-K. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineersread more
Citations
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Fast parallel algorithms for short-range molecular dynamics
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Journal ArticleDOI
Emerging challenges and materials for thermal management of electronics
Arden L. Moore,Li Shi +1 more
TL;DR: In this paper, a number of cubic crystals, two-dimensional layered materials, nanostructure networks and composites, molecular layers and surface functionalization, and aligned polymer structures are examined for potential applications as heat spreading layers and substrates, thermal interface materials, and underfill materials in future-generation electronics.
Journal ArticleDOI
Polymer nano-foams for insulating applications prepared from CO2 foaming
TL;DR: In this article, an analytical model of heat transfer in polymer foams and a CO 2 foaming process for the preparation of micro/nano-cellular polymer materials for insulating applications are reviewed.
Journal ArticleDOI
Experimental validation of the Knudsen effect in nanocellular polymeric foams
B. Notario,Javier Pinto,Javier Pinto,Eusebio Solórzano,J.A. de Saja,Michel Dumon,Miguel Angel Rodriguez-Perez +6 more
TL;DR: In this article, it has been shown that the reduction of the cell size has an effect on the thermal conductivity through the solid phase, this contribution is reduced due to an increment of the tortuosity of the cellular structure and/or a confinement effect in the polymeric matrix.
Journal ArticleDOI
Hollow-Structured Materials for Thermal Insulation.
Feng Hu,Siyu Wu,Yugang Sun +2 more
TL;DR: A timely overview of the recent progress in developing HSMs for thermal insulation is presented, with the focus on summarizing the strategies for creating gaseous voids in solid materials and thus synthesizing various HSMs.
References
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Journal ArticleDOI
Fast parallel algorithms for short-range molecular dynamics
TL;DR: In this article, three parallel algorithms for classical molecular dynamics are presented, which can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors.
Fast parallel algorithms for short-range molecular dynamics
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Journal ArticleDOI
Comparison of atomic-level simulation methods for computing thermal conductivity
TL;DR: In this article, the authors compare the results of equilibrium and nonequilibrium methods to compute thermal conductivity using Sillinger-Weber silicon as a model system, addressing issues related to nonlinear response, thermal equilibration, and statistical averaging.
Journal ArticleDOI
Thermal conductivity of carbon nanotubes
TL;DR: In this article, the thermal conductivity of nanotubes' dependence on structure, defects and vacancies was studied using the empirical bond order dependent force field, and it was shown that the carbon nanotube bundles have very high thermal conductivities comparable to diamond crystal and in-plane graphite sheet.
Journal ArticleDOI
High-thermal-conductivity, mesophase-pitch-derived carbon foams: effect of precursor on structure and properties
TL;DR: In this paper, a novel foaming technique and the evaluation of the foaming characteristics of two mesophase pitches (Mitsubishi ARA24 and Conoco Dry Mesophase) were presented.
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