Origin of high thermal conductivity in disentangled ultra-high molecular weight polyethylene films: ballistic phonons within enlarged crystals.

ABSTRACT: The thermal transport properties of oriented polymers are of fundamental and practical interest. High thermal conductivities ( ≳ 50 Wm^-1K^-1) have recently been reported in disentangled ultra-high molecular weight polyethylene (UHMWPE) films, considerably exceeding prior reported values for oriented films. However, conflicting explanations have been proposed for the microscopic origin of the high thermal conductivity. Here, we report a characterization of the thermal conductivity and mean free path accumulation function of disentangled UHMWPE films (draw ratio ~200) using cryogenic steady-state thermal conductivity measurements and transient grating spectroscopy. We observe a marked dependence of the thermal conductivity on grating period over temperatures from 30-300

SUBMITTER: Kim T 

PROVIDER: S-EPMC9068786 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature