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Heat conduction in metal‐filled polymers: The role of particle size, shape, and orientation
Author(s) -
Hansen David,
Tomkiewicz Robert
Publication year - 1975
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760150506
Subject(s) - materials science , thermal conductivity , composite material , thermal conduction , copper , particle (ecology) , conductivity , epoxy , composite number , particle size , conductor , electrical conductor , electrical resistivity and conductivity , polymer , volume fraction , metallurgy , chemical engineering , oceanography , chemistry , electrical engineering , engineering , geology
Elongated metal or other conductive particles can be added to a polymer or other poor conductor to produce a composite of enhanced conductivity. Elongated particles are generally more effective than spherical or irregular particles but very slender particles can be dramatically more effective. For example, cylindrical copper particles with length/diameter ( L / D ) = 20, randomly dispersed in epoxy resin at a loading of 5 percent copper by volume yield a composite with a thermal conductivity about 1.5 times that of the base resin. However, the same volume of copper particles with L / D = 50 can increase the conductivity by a factor of 5 or more. This paper presents a new type of analysis for predicting the thermal conductivity of disperse composites from the properties of the component phases and elementary characterizations of particle shapes and orientation. This analysis successfully predicted the sensitivity to particle shape which was confirmed by experiments also reported in this paper. These results suggest that highly elongated particles may be used to achieve dramatic modifications of thermal conductivity and the analysis presented here may be a useful tool in the design or development of disperse composites of specific thermal conductivity. The analysis may also apply to other properties such as electrical conductivity or magnetic permeability.