Isostatic compression process compacts certain powdered aromatic polymers into homogeneous materials that can be machined to form useful components, such as bearings. It provides for complete removal of air in the interstitial spaces surrounding the granules of the powdered polymer before the powder is subjected to isostatic compression

Ingham, J. D.

Lawson, D. D.

Ostrum, G. K.

English

NASA Technical Reports Server

Rubber Tubing 
Powdered Polymer Rubber Cement 
Cylin 
Filter Pr 
Neoprene
BEFORE EVACUATION
Vacuum Pump 
.Hollow Needle 
Filter Paper	 :.-: :
	
Neoprene Stopper 
Mold
.:.- Powdered Polymer 
Vacuum 
AFTER EVACUATION 
June 1967	 Brief 67-10168 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations -derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Isostatic Compression Process Converts Polyaromatics into Structural Material 
Rubber Cement Seal
Plunger 
Neoprene Stopper Neoprene 
Gasket 
Filter	 Faper
Neoprene 
Stopper 
Neoprene Mold
Neoprene 
Mold 
Powdered Polymer
Radial Hole to 
Facilitate Removal 
Vent Valve	 Rubber Cement Seal 
Brace Ring Neoprene 
Stopper 
Glycerine or Water Filter	 Paper 
Powdered Polymer Neoprene Mold 
PJ^Hydrostatic
Compressed 
 Chamber Polymer
BEFORE COMPRESSION	 AFTER COMPRESSION
LABORATORY APPARATUS FOR ISOSTATIC COMPRESSION 
The problem: 
To devise a process for compacting certain 
powdered aromatic polymers (e.g., polyphenylenes) 
into homogeneous materials that can be machined 
to form useful components, such as bearings. These 
materials are characterized by insolubility in strong 
bases, acids, and ordinary organic solvents; high-
temperature stability; high radiation resistance; and 
good lubricity. Because of their insolubility and 
infusibility, the polyaromatics could not previously be 
fabricated into useful structures.
The solution: 
An isostatic (hydrostatic) compression process, 
similar to that employed in the ceramics and powder 
metallurgy fields, but which provides for complete 
removal of air in the interstitial spaces surrounding the 
granules of the powdered polymer before the powder 
is subjected to isostatic compression. 
How it's done: 
The powdered polymer is placed into a neoprene 
mold that is retained within a cylinder, at the bottom 
of which is a neoprene stopper fitted with a filter 
(continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights. 
https://ntrs.nasa.gov/search.jsp?R=19670000168 2020-03-11T20:47:06+00:00Z
paper and a vacuum pump connector. The top of the 
mold is fitted with a filter paper and a neoprene 
stopper which is penetrated by a hollow needle whose 
upper end is connected to a vacuum pump. Rubber 
cement is used to edge-seal the upper neoprene stop-
per to the rim of the neoprene mold. 
All of the air is withdrawn from the contents of the 
mold and the space between the mold and the bottom 
of the cylinder by a vacuum pump. The hollow needle 
is then extracted from the upper stopper and the hole 
left in it is sealed with rubber cement. The flanged 
portion of the mold is finally lapped around the outer 
surface of the upper stopper and edge-sealed with rub-
ber cement at the points of contact. The prepared 
mold (third figure) containing the air-free powdered 
polymer is placed in a conventional hydrostatic 
chamber (fourth figure) for isostatic compression of 
the polymer into a compact machinable billet as indi-
cated in the fifth figure.
Notes:	 - 
I. Bearings made of a polyaromatic material pro-
duced by this process have a very low coefficient of 
friction in a hard vacuum as well as in air and were 
found to have a much longer life than bearings 
made of polytetrafluoroethylene. 
2. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: B67-10168 
Patent status: 
No patent action is contemplated by NASA. 
Source: G. K. Ostrum, D. D. Lawson, 
and J. D. Ingham 
(JPL-892) 
Brief 67-10168	 Category 03


Isostatic compression process converts polyaromatics into structural material

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