Thermal conductivity of highly oriented polyethylene

For disentangled UHMWPE of draw ratio ≳150, the thermal conductivity is observed to increase on average by a factor of about 20% despite a lack of detectable change in crystallinity or chain orientation.

“For disentangled UHMWPE of DR ≳ 150, the increase in thermal conductivity is difficult to interpret using the above models because the thermal conductivity is observed to increase on average by factor of ∼20% despite a lack of detectable change in crystallinity or chain orientation11–13,23,24.”

The enhancement of thermal conductivity in oriented polyethylene was attributed to mechanisms including increased chain alignment along the drawing direction, phonon focusing in the elastically anisotropic crystalline phase, and increased crystallinity.

“The enhancement was attributed to various mechanisms including increased chain alignment along the drawing direction7,14, phonon focusing in the elastically anisotropic crystalline phase15,16, and increased crystallinity12,17.”

The reported thermal conductivity of oriented polyethylene ranged from about 14 W m−1 K−1 for draw ratio 25 up to about 40 W m−1 K−1 for solution-processed polyethylene with a draw ratio of 350.

“In particular, the reported thermal conductivity of oriented polyethylene ranged from ∼14 Wm−1 K−1 (ref. 12) for draw ratio DR = 25 up to ∼40 Wm−1 K−1 for solution processed PE with a DR of 350 (ref. 13).”