Characterization of radiation-crosslinked, high-density polyethylene for thermal energy storage applications. [Electron beams]

Conference · Thu Jan 01 04:00:00 EST 1981

OSTI ID:6320219

Whitaker, R B; Craven, S M; Etter, D E; Jendrek, E F

This study is directed toward characterization of the crosslinked, form-stable high-density polyethylene (HDPE) pellets produced by electron beam radiation crosslinking, and the effects of crosslinking on crystallinity and heat of fusion. Methods used include differential scanning calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and x-ray diffraction measurements. DSC measurements of the heats of fusion (..delta..H/sub f/) of the radiation-crosslinked HDPE showed that while a substantial decrease in ..delta..H/sub f/ occurred after the first melting cycle, slow cooling on recrystallization of the pellets could restore the ..delta..H/sub f/ value to greater than or equal to 95% of that of the uncrosslinked HDPE up to 9.0 Mrad dosage exposure. The form stability of the 9.0-Mrad HDPE was very good even after 500 melt-freeze cycles in ethylene glycol. However, some further decline in ..delta..H/sub f/ was noted and more extensive thermal cycling tests would be required to verify this. X-ray diffraction measurements showed little or no difference in crystallinity among the various radiation-crosslinked HDPE's and the uncrosslinked control HDPE. This indicates the crosslinking occurs primarily in the amorphous regions of the polyethylene. FTIR spectroscopy was used to estimate the relative amounts of crosslinking occurring with the varying radiation dosages, and the uniformity of crosslinking throughout the pellets. The relative amount of crosslinking was based on the ratio of the 965 cm/sup -1/ absorption band to the 909 cm/sup -1/ band. This ratio did increase with increasing radiation dosage: from 1.9 for the crosslinked HDPE dosed with 9.0 Mrad, to 5.3 for that dosed with 18.0 Mrad. Also, the amount of crosslinking from the outside to the center of the pellets was found to be uniform, which would assist in maintaining long-term form stability in the pellets.

• Research Organization: Mound Facility, Miamisburg, OH (USA)
• DOE Contract Number: AC04-76DP00053
• OSTI ID: 6320219
• Report Number(s): MLM-2836(OP); CONF-811014-1; ON: DE81024915
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250600 -- Energy Storage-- Thermal
250800 -- Energy Storage-- Chemical
36 MATERIALS SCIENCE
360406* -- Materials-- Polymers & Plastics-- Radiation Effects-- (-1987)
ABSORPTION SPECTROSCOPY
BEAMS
CALORIMETRY
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
COHERENT SCATTERING
CROSS-LINKING
CRYSTAL STRUCTURE
DATA
DIFFRACTION
ELECTRON BEAMS
ENERGY STORAGE
ENTHALPY
EXPERIMENTAL DATA
FOURIER TRANSFORMATION
FUSION HEAT
HEAT STORAGE
INFORMATION
INFRARED SPECTRA
INTEGRAL TRANSFORMATIONS
LATENT HEAT STORAGE
LEPTON BEAMS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PARTICLE BEAMS
PHYSICAL PROPERTIES
POLYETHYLENES
POLYMERIZATION
POLYMERS
POLYOLEFINS
RADIATION CHEMISTRY
RADIATION EFFECTS
SCATTERING
SPECTRA
SPECTROSCOPY
STORAGE
THERMODYNAMIC PROPERTIES
TRANSFORMATIONS
TRANSITION HEAT
X-RAY DIFFRACTION