The flash technique has been used on a systematic series of drawn lowhyphen;density polyethylenes. Results from two different temperature monitoring modes are compared. Both the temperature rise of the rear face and the difference between fronthyphen; and rearhyphen;face temperatures was measured on each sample using the same instrumentation. A positive difference of 10percnt; in the thermal diffusivity by the rearhyphen;face analysis was observed over the differential method. Radiation loss corrections were applied to both analyses and estimated by a heat balance for the differential case. Instrument pressures below which losses to the air become negligible were calculated and experimentally confirmed. The thermal conductivity calculated from diffusivity for the lowhyphen;density polyethylenes is shown to be proportional to the extent of deformation in the draw direction.
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