IX. THERMAL EXPANSIVITY OF SOLIDS

THERMAL EXPANSION OF TEFLON
Sources of Data: Laquer and Head 1952
Other References: Dunsmoor et al. 1958
Trepus et al. 1959
Wood, Bekkedahl and Peters 1939.
Discussion: Polytetrafluoroethylene . Extruded and
annealed sample measured by Kirby 1956.
He found that strained samples could have
expansions larger or smaller than those of
annealed Teflon, the differences being as
large as 20%. Laquer and Head (1952) measured two
samples of DuPont Teflon rod taken normal
and parallel to the extrusion directicn.
The expansions parallel were roughly 15%
larger than those normal, and the average
is 10 to 15% larger than the the above data
by Kirby. The data of Laquer and Head were
used only to guide the extrapolation of Kirbyts
values below 80°K. Teflon has a first order
transition at 2OoC. Therefore we use 25O C
as a reference temperature and tabulate lo5
(L298-LT) L298 above.
Temp
0
K
0
20
40
60
80
LOO
120
140
Table of Selected Values
L293 - LT
L293
2140 x
2110
2060 I'
2000 I1
1930 I'
1850 I'
1760 'I
1660 It
Taken from NBS 29
Temp,
OK
160
180
200
2 20
240
2 60
273
298
IX-R-8.1
L2 93 - LT
L293
1540 x lom5
1400
11
1240
I1
1050
I1
855
I1
645
I1
500
I1
0
11