Ca. Swenson, LINEAR THERMAL EXPANSIVITY (1.5-300 K) AND HEAT-CAPACITY (1.2-90 K) OF STYCAST-2850FT, Review of scientific instruments, 68(2), 1997, pp. 1312-1315
Linear thermal expansivities, alpha, have been obtained from 1 to 300
K for a sample of Stycast 2850FT epoxy that initially was cured at roo
m temperature (X1), and then at 95 degrees C (X2). Heat capacities, C-
p, were measured from 1 to 95 K for X2. The alpha's for X1 and X2 are
roughly equal to and twice that of copper near room temperature, but d
iffer by as much as 10% at low temperature. The alpha's approach those
for copper near 100 K, but have a much smaller temperature dependence
at lower temperatures. The different shapes of the alpha(T) and C-p(T
) relations give a Gruneisen parameter, Gamma, which decreases from 1.
2 at 10 K to 0.5 at 95 K. Both alpha and C-p show apparent changes in
lattice properties near 4.5 K, and a low temperature anomaly (Gamma =
3.5) that is characteristic of amorphous solids. Sample relaxation (sh
ortening) effects from 300 K to 110 K were more serious for X2 than fo
r X1. Because of differences related to the curing procedure? these da
ta should be used only semiquantitatively in the design of experiments
in which Stycast 2850FT will be used as a construction material. Poss
ible Stycast-related problems with a capacitance dilatometer are discu
ssed. (C) 1997 American Institute of Physics.