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Shear‐induced anisotropy in thermal conductivity of a polyethylene melt
Author(s) -
Picot J. J. C.,
Goobie G. I.,
Mawhinney G. S.
Publication year - 1982
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.760220304
Subject(s) - materials science , thermal conductivity , composite material , anisotropy , thermal conduction , heat flux , polyethylene , cylinder , thermal , thermal diffusivity , conductivity , shear (geology) , heat transfer , thermodynamics , optics , chemistry , engineering , mechanical engineering , physics
A rotating concentric‐cylinder thermal conductivity cell for polymer liquids is described. Thermal conductivity can be measured at temperatures approaching 200°C and at strain rates up to 400 s −1 , The transient heat flux probe (with inner cylinder as heat source and temperature probe) method is used to permit the separation of the viscous heating effect from the probe heating effect. A polyethylene melt was studied and showed that at 50 s −1 , a 2 percent increase in thermal conductivity occurs, followed by a gradual decrease until a value 10 percent less than the no‐shear thermal conductivity was found at 400 s −1 . This effect is due to molecular orientation.