and SE-550. The properties of these 
materials undergo very nearly the same 
changes, but at any given radiation 
dose, the SE-550 is much more flexible 
and appears in better over-all condition. 
Weight and thickness measurements 
do not indicate the condition of a mate- 
rial. Teflon at an exposure of 5 X 
10° r had not changed in either weight 
or thickness but was extremely brittle 
and crumbly. 
Elasticity appears to offer the same 
advantages as does elongation. How- 
ever, because of the scale used (0 to 
100), materials having an initial elas- 
ticity of 6, which lowers to 3 after expo- 
sure, have essentially undergone less 
change than those materials that change 
from 30 to 15—the over-all change 
being a 50% reduction in elasticity. 
Also, in the first case because of the low 
values, a larger error is introduced be- 
cause of the measurement method. 
Materials. The styrene rubber PR 
408-70 is affected less than the other 
materials investigated. This is due to 
the presencé of the styrene, which is 
able to absorb greater amounts of 
energy from radiation without being 
altered to the same degree as the other 
materials. The acrylics, neoprenes, 
and nitrile classes all appear to be about 
equally damaged. 
Teflon is the poorest of all the mate- 
rials evaluated. It is severely dam- 
aged at 5 X 108 r. Kel-F elastomer 
and Hycar 2202 (butyl type) both 
softened and became tacky, indicating 
poor suitability in radiation fields. 
The remainder of the ethylene mate- 
rials appear to be in the same class as 
the acrylics, neoprenes, and nitriles on 
the basis of the longerexposures. How- 
ever, intermediate doses affected the 
ethylenes in a different manner; prop- 
erties were either upgraded or degraded 
depending upon the amount of exposure 
received. 
The vinyls appear to sustain less 
damage than all other materials except 
the styrene-type rubber. The silicone 
elastomers as a class are inferior to all 
other classes except the fluorocarbons 
and butyl. However, within the sili- 
cone class, the phenyl types are supe- 
rior to the methyl and vinyl types ow- 
ing to the presence of the benzene ring. 
Data presented for all exposures at 
5 X 10° r show conclusively that most 
materials are significantly affected by 
this dose, and shorter exposures are 
needed before the complete representa- 
tion of property changes can be shown. 
Weight 
—0.15 
—0.03 
0.50 
0.32 
—0.41 
0.20 
Tensile 
(pst; A%) (A%) 
—-13.6 
-15.8 
—61.8 
—64.0 
—54.8 
2,130 
—100 
8 
Elongation 
(%; 4%) 
390 
—-12.4 
—25.3 
—66.5 
—75.5 
—80.7 
345 
—12 
6.06 
66 
—24.2 
—24.2 
—39.9 
—69.7 
44 
—84.1 
Initial properties and percent change 
Elasticity 
—3.13 
—3.13 
3.13 
9.38 
12.5 
64 
73 
—38.4 
Hardness 
(Shore A; A%) (Shore; A%) 
Radiation 
exposure 
(10®r) 
5 
10 
50 
100 
150 
10t 
50t 
100t 
150tttt 
0 
5 
; TMTD, 
Cured 30 min at 
310° F; post cured 24 hr 
at 300° F 
recipe 
2 
Material and 
26 
Cured 30 min at 
310° F; post cured 24 hr 
at 300° F 
Hycar 2202, 100.00; 
stearic actd 1,00; zinc 
ETHYLENES 
Agilene, white, polyethylene (low-density type—no. avg. mol. wt. = 22-24,000), American Agile Corp. 
Hycar 4021, black, ethyl acrylate and chloro ethyl vinyl ether, B. F. Goodrich Chemical Co. 
BUTYL 
Hycar 2202, brominated copolymer of isobutylene and isoprene, B. F. Goodrich Chemical Co. 
Hycar 4021, 100.0; 
oxide, 5.00; Philblack 0, 
50.00; Blackbird sulfur, 
2.00; benzothiazial di 
sulfide, 0 
zial disulfide, 2.0; TETA, 
0.50. 
stearic acid, 1.0; Phil- 
black A, 40.0; benzothia- 
1,5. 
No additives 
0.60 
0.12 
0.0 
0.0 
0.55 
0.13 
Weight 
—0.20 
(Shore A; 4%) (Shore; A%) (%;4%) (psi; 4%) (A%) 
10.4 
Tensile 
-5.3 
1,885 
-7.4 
-0.9 
-18.9 
—25.1 
970 
Elongation 
—47.2 
—41.9 
435 
—24.0 
—21.7 
—56.2 
—63.1 
275 
0.0 
—46.7 
—46.6 
15 
80.0 
66.7 
—13.3 
—40.0 
Initial properties and percent change 
Elasticity 
Hardness 
0.0 
2708 
—-8.3 
-9.5 
—4.8 
68 
Radiation 
exposure 
(108r) 
10 
50 
100 
150 
10 
50 
100 
150 
0 
0 
5 
recipe 
Cured 30 min at 
Material and 
TABLE 2—How Gamma Radiation Affects Properties of Plastics and Elastomers 
Acrylon BA-12, black, copolymer of an acrylic ester and acrylonitrile, Borden Co. 
Acrylon EA-5, black, copolymer of an acrylic ester and acrylonitrile, Borden Co. 
Vyram, black, acrylate, Monsanto Chemical Co. 
1.0; triethylene tetramine, 
2.0; SRF black, 50.0. 
stearic acid, 1.0; sulfur, 
1.0; triethylene tetra- 
mine, 1.0; SRF black, 
Vyram, 100.0; CC black, 
30.0; silica, 10.0; oleic 
Acrylon BA-12, 100.0; 
Stearic acid, 1.0; sulfur, 
Cured: 30 min at 310° F 
Acrylon EA-&, 100.0; 
ACRYLICS 
50.0. 
310° F 
0.01 
0.04 
0.05 
nN 
10 
40.1 
—27.0 
—34.3 
—72.6 
—83.6 
—87.2 
0.0 
—31.2 
—68.8 
—68..7 
=f159 
5.3 
—5.8 
5 
-0.56 
=—10.7 
.50 
1 
0.51 
12.6 
—-11.7 
—0.72 
16.2 
33.8 
10 
50 
100* 
150* 
acid, 1.0; stearic acid, 3.0; 
magnesium oxide, 10.0; 
divinyl benzene, 3.0; 
Cured 30 min at 330° F 
dicumyl peroxide, 3.0. 
