Heat capacity measurements on polyethylene in the temperature range of 2.4 to 30°K.
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Authors
Tucker, James Earl
Subjects
Advisors
Reese, William
Date of Issue
1966-05
Date
Publisher
Monterey, California. U.S. Naval Postgraduate School
Language
en_US
Abstract
Specific heat measurements on three samples of polyethylene,
differing only in density, were made in the temperature range of 2.H
to 30°K. A definite density dependence was noted for the specific
heat in this temperature interval which allowed extrapolation of the
data to completely crystalline and completely amorphous cases. At
the lowest temperatures, the amorphous results were observed to display
an "excess" heat capacity which could be accounted for by the
occurance of a single delta function peak in the low frequency part
of the vibrational spectrum. This excess did not appear in the completely
crystalline extrapolated data, and the specific heat was found
to be proportional to the cube of the temperature up to 9°K. An attempt was made to compare the results with two theoretical
models (Tarasov and Stockmayer-Hecht) with only fair agreement in one
case, and none in the other. The agreement with previous experimental
results is excellent if the density dependence and the excess heat
capacity are considered.
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Thesis
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Distribution Statement
Approved for public release; distribution is unlimited.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.