Accession Number : ADA310439
Title : Investigation of Microstructural Changes in Polyetherether-Ketone Films at Cryogenic Temperatures by Positron Lifetime Spectroscopy.
Descriptive Note : Technical paper,
Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
Personal Author(s) : Singh, Jag J. ; Eftekhari, Abe ; St Clair, Terry L. ; Sprinkle, Danny R.
PDF Url : ADA310439
Report Date : MAR 1991
Pagination or Media Count : 13
Abstract : Microstructural changes in polyetherether-ketone (PEEK) films have been investigated in the temperature range of 23 deg C to -196 deg C by using positron lifetime spectroscopy. It has been determined that the total free volume decreases by about 46 percent in amorphous PEEK samples and about 36 percent in semicrystalline PEEK samples when they are cooled from room temperature to the temperature of liquid nitrogen. If this trend in reduction of free volume with decreasing temperature continues, as expected, PEEK should be able to withstand cooling to the temperature of liquid hydrogen without any detrimental effect on its diffusivity for liquid hydrogen.
Descriptors : *TEMPERATURE, *MICROSTRUCTURE, *SPECTROSCOPY, *MODIFICATION, *CRYOGENICS, *POLYETHERS, *KETONES, *POSITRONS, LOW TEMPERATURE, POLYMERS, FILMS, COOLING, ROOM TEMPERATURE, REDUCTION, DIFFUSION, LIQUID HYDROGEN, LIQUID NITROGEN.
Subject Categories : Polymer Chemistry
Atomic and Molecular Physics and Spectroscopy
Distribution Statement : APPROVED FOR PUBLIC RELEASE