New leaching process removes uncured polymer from nitroso rubber, elastomer used in presence of nitrogen tetroxide. Uncured portion is removed by controlled soaking of polymer slab in Freon TF. Leaching with Freon TF prevents nitroso rubber from adhering to adjoining surfaces and limiting its usefulness in either static or dynamic applications

Bratfisch, W. A.

Gonzalez, R.

English

NASA Technical Reports Server

August 1972
	 B72-10449 
•	 NASA TECH BRIEF 
Manned Spacecraft Center
	 -4r 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Leaching of Nitroso Rubber Material Removes Uncured Polymer 
A new leaching process removes the uncured poly-
mer from nitroso rubber, an elastomer used in the pres-
ence of N204
. The uncured portion is removed by con-
trolled soaking of a polymer slab in Freon TF.
Uncured polymer causes nitroso rubber to adhere 
to adjoining surfaces limiting its usefulness in either 
static or dynamic applications. Leaching with Freon TF 
prevents this adhesion. 
Physical Properties
Sample 
Ident. Exposure
Tensile 
Strength 
10 6 N/m 2	 (Si)
Elongation 
Percent
Percent 
Set
Shore 
Hardness 
A As Molded 6.49	 (940) 250 60 
B As Molded 6.69	 (970) 320 60 
C N204 33.0 65 
D N204 33.0 61 
Freon 
E N204 25.0 61 
Freon 
F N204 27.0 62 
G N204 4.90	 (710) 500
. 
H N204 4.35	 (630) 520 57 
Freon 
J N20 5.04	 (730) 450 56 
Freon 
K N204 5.31	 (770) 540 56 
L Freon 6.69	 (970) 280 61 
M	
I Freon 6.69	 (970) 300  61
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use Government nor any person acting on behalf of the United States
	 will be free from privately owned rights. 
https://ntrs.nasa.gov/search.jsp?R=19720000448 2020-03-17T03:39:31+00:00Z
The results of the leaching process are shown in 
the table. Samples A and B were tested as molded. Sam-
ples C, D, G and H were maintained as a control. Sam-
ples E, F, J, K, L and M were soaked in Freon TF for 
3.0 hours and then vacuum dried for 3.0 hours at 
46 ± 5.5°C (115 ± 10°F) and 127 mm (5 in.)Hg. After 
the Freon TF exposure samples E and F and control 
samples (unexposed to Freon TF) C and D were bent 
double around a 0.32 cm (1/8 inch) diameter rod. These 
samples along with control samples G and H and treated 
samples J and K were immersed in N 2 04 , and maintained 
at 66 ± 5.5°C (150 ± 10°F) for 15 days. Upon comple-
tion of the N 2 04 exposure samples G, H, J and K were 
allowed to outgas and air dry for 120 hours. Samples C, 
D, E and F were tested for permanent set within 3 to 5 
minutes of end separation and then allowed to outgas 
and air dry for 120 hours before a shore hardness test 
was performed. 
This technique may be applicable in chemical pro-
cessing for anti-stick valves, pumps and diaphragms.
Note:
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Manned Spacecraft Center 
Code JM7 
Houston, Texas 77058 
Reference: B72-10449 
Patent status: 
No patent action is contemplated by NASA. 
Source: Warren A. Bratfisch and Rudy Gonzalez 
North American Rockwell Corp. 
under contract to
Manned Spacecraft Center
(MSC-17185) 
B72-10449	 Category: 04


Leaching of nitroso rubber material removes uncured polymer

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