Fluorinated prepolymers are used to generate highly fluorinated polymers which possess most of the desirable properties of polytetrafluoroethylene, such as nonflammability and high corrosion resistance, while retaining good low temperature flexibility

Rochow, S. E.

Stump, E. C., Jr.

English

NASA Technical Reports Server

January 1971	 Brief 71710004 
NASA TECH BRIEF 
NASA Pasadena Office	
_4V 
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. 
Preparation of Perfluoropolyether Prepolymers 
.
A new group of fluorinated prepolymers can be 
used to generate a wide variety of highly fluori-
nated polymers. The polymers possess most of the 
desirable properties of polytetrafluoroethylene, such as 
nonflammability and high corrosion resistance, while 
retaining good low temperature flexibility. 
The nrepolymers have the general formula: 
X[CF(CF3
 )O(CF2 ) 0OCF(CF 3 )1 X 
where n is an integer from 2 to 12, 
p is an integer from 2 to 23, and 
Xisanorganic group, either the acid fluoride 
-COF or the methanol group -CH20H. 
The prepolymers are derived by subjecting a diacid 
fluoride perfluoroether (the above formula with 
n = 1 and X = -COF) to ultraviolet irradiation. 
By a process of photochemical coupling, molecules 
bearing the acid fluoride termination are created with 
the value of n ranging from 2 to 12. The pre-
dominant value of n in the product may be con-
trolled by varying either the intensity and wave-
length of the UV or the exposure time. Satisfactory 
prepolymers, with n ranging from 2 to 4 (molecular 
weight approximately 1200 to 2300), have been ob-
tained through irradiation for four days with a 450 
watt UV source. 
To obtain hydroxy-terminated (diol) compounds, 
which are even more useful as prepolymers, the acid 
fluoride-terminated form is reduced by reaction with 
either lithium aluminum hydride or sodium boro-
hydride. The prepolymer is dissolved in a solvent 
such as Freon 113, and the solution is added to 
the reducing agent dissolved in diethylene glycol di-
methyl ether. The reaction is performed under 
anhydrous conditions to prevent hydrolysis of the 
acid fluoride group.
Notes: 
1. Information on a continuation of this work, in-
volving the use of the perfluoropolyether pre-
polymers to forni fluorinated polyurethanes, 
may be found in NASA Tech Brief B71-10005. 
Other related information is contained in NASA 
Tech Brief B70-10353. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP71-10004 
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed. Royalty-free nonexclusive 
licenses for its commercial use will be granted by 
NASA. Inquiries concerning license rights should be 
made to: 
Patent Counsel 
Mail Code 1 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Source: E.C. Stump, Jr. and S.E. Rochow of

Peninsular ChemResearch Inc.

under contract to

NASA Pasadena Office

(NPO- 10765) 
Category 04 
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=19710000004 2020-03-17T02:17:55+00:00Z


Preparation of perfluoropolyether prepolymers

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