Possibilities of thermoluminescence method for estimating the molecular packing in near-surface layers of polymers
The effect of crystallization conditions on the relaxation properties of ultra-thin surface layers in the melt-grown ultra-high molecular weight polyethylene samples was studied using a novel Nanoluminograph device. The device can record thermoluminescence generated upon heating the sample preactivated by high-frequency low-temperature low-power glow-discharge plasma. The glow curves were analyzed, and activation energy of thermoluminescence for the observed glow maxima was calculated. The effect of crystallization conditions on the formation of a lamellar structure on the surface of ultra-high molecular weight polyethylene was examined. The possibility of structural characterization of disordered interlamellar regions using thermoluminescence data is discussed. The estimated activation energy of thermoluminescence was used to calculate the apparent dimensions of kinetic units of motion in the region of β transition, which are supposed to characterize the cooperativeness in the motion of molecular segments.