Method for producing alternating ether-siloxane copolymers with stable properties when exposed to elevated temperatures and UV radiatio

Curry, J. E.

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ATTN OF: GP 
NATIOIMAL AERON UTICS hND SPACE ADMlMlSTRATlON 
WASHINGTON. D.C. 20546 
TO t USI/Scientific & Technical. Information Division 
Attention: Niss Winnie M, Morgan 
GP/Office of Assistant General 
Counsel for Patent Matters 
SUBJECT: Announcement of NASA-Owned 
U , S ,  Patents in STAR 
In accordance with the procedures contained in the Code GP 
to Code US1 memorandum on this subject, dated June 8, 1970, 
the attached NASA-owned U,S. patent is being forwarded for 
abstracting and announcement in NASA STAR, 
The following information is provided: 
U,S. Patent No. 
Corporate Source 
Supplementary 
Corporate Source 
Marshall Space Flight Center 
NASA Patent Case No,: -02584 
Gable Parker 
Enclosure: $ y .  -- 
(ACCESSION NUMBER) 
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fR1R2SiOR303- 
The copolymers which are produced in a relatively short 
period of time have relatively high molecular weights, 
,and are resistant to or stable at relatively high tempera- ’ tures. It is important to understand the ifactors which 
contribute to obtaining copolymers displaying the afore- 
mentioned properties are the intermediates employed, Le., 
diaminosilanes and diols, the method of polymerizing, the 
temperature at whioh polymerization is performed, the This invention relates to a method for producing alter- 10 period of time for polymerization, and the fact the inter- 
cyclic products to the exclusion of high molecular weight 
nating ether-si1oxane copolymers, which “play the prop- mediates employed do not form low molec.ar weight erties of being relatively stable at elevated temperatures 
and when exposed to ultraviloet radiation. 
The rapid growth of technology in substantially all in- 
dustries and scientific disciplines and particularly in the 15 R I R ~ N N I ~ R ~ )  (NHR4) 1- HO-R3-OH ---+ 
aerospace industries has imposed a need on the industries 
erties which are resistant to existing and anticipated de- 
structive elements and forces and which will withstand 
the rigors of the space environment. This need is evident 20 The reaction taPerature is adjusted to Permit the at- 
in every phase of spacecraft and aircraft development. One tainment of high molecdar Weights within a reasonable 
of the critical areas is the development of improved non- time, and the WmPlete removal of the amines evolved ‘m 
metallic materials for use as coatings, plastics, iadhesives, a by-product of the Polymerization reaction is facilitated 
elastomers, as well as fibers and films. These materials are by the &mltaneOus aPPlication of heat and V w m n -  The 
c h b m l l y  produced and composed of complicated long 25 reaction may be conducted in a suitably inert highdboiling 
chain molecules known as polymers, and a rigorous re- solvent, or the reactants may be mixed and heated above 
search program for the development of new polymers has their melting Point in the ahence Of a solvent. 
been undertaken to obtain such materials which will meet The alternating ether-siloxane copolymers may be 
the aforementioned requirements or needs. forced into fibers or films, they may be applied as ad- 
30 hesives or cuatings, and they may have fillers, pigments 
Mted as films or fibers, or which may be applied as mat- ,and reinforcements admixed therewith if condition of ex- 
ings and adhesives, one of the basic goals of the research posure and use 5 0  dictate. 
program is to produce thermally stable polymers or coply- 
mers which may be employed in the aforementioned man- 
ner, yet, which maintain their beneficial properties at ele- 
vated tempefiatures. The mere existence of polymers or 35 ordered repeating unit is not iunknown, but the prior art Processes were deficient in that the polymers were of a 
low ~olecular  wei&t. For instance, one known process 
for Preparing polymers of the stated oomposition is based 
linear polymers. The reaction 
for new materials. These materids are to include prop- -[ r-O-Fb-O]- + RsNHs? + RnNHat 
R2 
Besides providing new materials Thich may be 
The production of polymers containing the 
(RlR2SiOR30) 
copolymers at elevated temperamres requires that no sig- 
nificant portion of their chemicd bonds degrade at that 
tempeq-ature. Additionally, it is desirable that extended 
ultraviolet radiation does not materially affect the polymers 40 
or copoIymers. RlRzSi(OR4) 2+HO-R3-(3H-;, 
Heretofore the service temperature of polymers and co- 
polymers is considerably lower than that *which is de- 
sired. At present, this service temperature presents 
Severe limitations in 
a nroblem area whioh. at least in Dart. bas been solved bv 
the alcOholysis reaction: 
( R1R$iOR30 ) ,+R40Ht 
‘of silicon dihalides and organic diols, as shown in 
It is also possible to prepare palmers b~ the direct re- 
uses of polymers and represents 4 j  ,action the reacfion: 
the development of &e alternating ether-siloxane cmp01;- 
mers. Additionally,.dwing long tWn’l exPosure to space ea& case, the polymeric products formed by prior 
many changes in the chemical ,and resultant mechanical 50 weight, and do not possess the deskable m&,anicd prop- 
properties. The chemical and radiation effects of the space erties associated with true high molecul,ar weiglzt polymers. 
envimment on p o h e r s  and cwolymers acting separate- Furthermore, the starting intermediates are in 
ly or in oonjunctiqn with each other has had a tendency each within the spirit of to disooufiage the ‘use of such materials. 
The effects of heat and ultraviolet radiation with regard It has been determined high molecu~ar weight, alter- 
to surface coatings of spacecraft ~ n d  vehicals =e of par- nating ether-siloxane copolymers may be produced by 
ticular concern. Most satellites ,and space vehicles have employing as intermediates organic diols or dihydroxy 
those satellites and vehicles which generate heat internally 60 Each element of the process including the polymerization 
thermmal surfaces. There are many Cases and instances 
which indicate and require materials with high tempera- 
ture stability. 
zation of organic diols with stable silazanes or dkmino- 
silanes having the general formula 
R1R2SiC;1z+HO-R3-OH-+ ( R1RzSiOR30)~+HCl~ 
environment, polymers and O O P O ~ Y ~ ~ ~ S  have undergone art processes are of a relatively low average mo1ecular 
different from those 
ST, this invention. 
some type Of 
and Often a coating is 
from Onboard equipment, it is 
coating On their exterior surfaces 
to interior surfaces. For compounds, together with stable silaanes or. diamine silanes which are polymerized under suitable conditions. 
process and the intermediates employed contributes to to have 
obtaining high molecular weight copolymers~ 
A typical polymerization is conducted as follows: 
Equimolar amounts of the intermediate monomers are 
a liquid take-oe condenser and a vacuum source. 
Heat is applied uniformly to the container to helu remove 
Briefly, the instant invention encompasses the PoVmeri- placed in a thick-walled resin container which is equipped 
the amine-as it is evolved. The monomers may be mixed 
in the solid state or dissolved in some suitable inert high- 
This results in the omduction of alternating ether-siloxane 70 boiling solvent. Heat is aoulied slowlv until an effective 
R1R&(NHR3) (NHR4) 
copolymers having the general formula op polymkzation temperature of about 300-325” C. is at- 
3,346,515 
4 
tained. After melting or solution of the monomers occur, 
the mixture is thoroughly stirred for about 30 minutes at 
which time a vacuum is applied slowly until about 1 
When each of the identified diols is reacted with the 
diamino silane derivative above, the following alternating 
ether-siloxane copolymers are obtained: 
is aryl or aryl combinations, alkyl or alkyl combinations, 
or alkylaryl combinations. Depending upon the monomers Copolymer 
and polymerization conditions employed, molecular 55 
weights ranging from 40,000 to 180,000 are generally --- 
obtained. These are merely typical values and do not I ______-____________ 
I1 _____-____________ 
I11 ____-____________  
One silazane found to be effective for producing the IV ____-__-__-.-____ 
copolymers is bis-(anilinoldiphenylsilane. However, it is 60 &-::::::-:::::::: 
to be understood that many silazanes or diaminosilanes VI--------..------. 
VI1 _ _ _ _ _ _ _ _ _ _ _ _ _ _  _ _  
constitute the limits bf the process described. 
may be substituted for that which has been identified. 
Copolymer Structure I Copolymer Number 
Percent 
C H s i  
Empirical Formula 
----- 
(ClsH~iOaSi)~ 73.43 4.54 10.49 
(ClsHlaOaSi) 74.45 4.86 10.56 
(CzrHlsO&i)rr 78.13 4.94 8.7 
(CazHleOaSi). 77.67 4.74 8.92 
78.41 5.94 7.10 [ ~ ~ ~ $ $ ] :  71.13 7.11 9.86 
(Ct4HlsOsSi). 75.46 4.67 7.96 
( CPIHsoOzSi)n 74.7s 5.08 10.7 
Copolymer Name 
poly-(l4-bisomhenylene)- 
diphdnylsilane. 
poly-(i 3-bisoxypheny1ene)- 
diphenylsilane. 
Poly-(4,4'-b!soxybiphenylene)- 
diphenylsllane. 
Poly-(2 7-bisoxynaphtha1ene)- 
diphdnylsilane. 
Poly-diphenylsilyl-[2 Zbis- 
(4-oxyphenylene)-~ropane]. 
Poly-(I &bisoxyhexamethylene) - 
diphekylsilane. 
Poly-diphenylsilyl-(4 4'- 
bisoxydiphenylethdr) . 
mm. of Hg vacuum is attained. An effective polymeriza- When a mixed diol composition containing equimolar 
tion heating time is maintained for between about 4-7 proportions of p,p'-biphenol and 1,6-hexanediol is re- 
hours. The effective polymerization temperature, the 35 acted with bis- (anilino) diphenylsilane in the manner 
period of heating considered also with the amount of the prescribed, the following alternating ether-siloxane co- 
vacuum and the ,intermediates employed all contribute to polymer is obtained. 
Copolymer Struetwe Copolymer 
Number 
I 
d 
r -  I 
3,346,515 
any other suitable solvents. Suitable pigments reinforce- (c) dwelling at said temperature for a period of about 
ments and fillers may also be admixed with the bulk poly- 4 to 7 hours under a vacuum, whereby relatively high- 
mers when dictated by conditions of usage or service. molecular-weight copolymers are obtained. 
While the present invention has been described herein 2. The method according to claim 1 wherein said di- 
in what is considered to be preferred embodiments thereof, 5 aminosilane monomer is bis-( anilino) diphenylsilane. 
it should be recognized that departures may be made there- 3. The method according to claim 2 wherein said diol 
from within the scope of the invention, and it should there- monomer consists of substantially equimolar proportions 
fore not be limited to the details of the within disclosure, of p,p'-biphenol and 1,6-hexanediol. 
but should be accorded the full scope of the appended 
References Cited 
What is claimed is: UNITED STATES PATENTS 
I. A method of producing alternating ether-siloxane 2,676,163 4/1954 Speier _ _ _ _ _ _ _ _ _ _ _ _ _  260-46.5 
2,993,871 7/1961 Shannon et al. _ _ _ _ _ _  260-46.5 (a) admixing a diaminosilane monomer having the for- mula RlR2si(mR,) (NHR4) wherein R1, R2, RB, p5 3,032,528 5/1961 Nitzsche et al. _ _ _ _ _ _  260448.2  
3,043,798 7/1962 Boyer et al. _ _ _ _ _ _ _ _  2 6 0 4 6 . 5  
3,133,110 5/1964 Morehouse et al. _ _ _ _  26-63 and R4 are aryl groups and a diol mononler selected from the group consisting of hydroquinone, p,p'-bi- 
phenol, 2,7-naphthalene diol, 2,2-propene-bis-(4- 
hydroxybenzene) , 1,6-hexanediol, and 4,4'-dihy- 
droxydiphenyl ether. 
claims. XO 
copolymers which comprises: 
DONALD E. CZAJA, Primary 
go LEON J. BERCOVITZ, Examiner. 
(b) heating the resulting mixture to a temperature of M. 1. MARQUIS, ~~~i~~~~~ ~ ~ ~ ~ i ~ ~ ~ .  
about 300" to 325" C.; and 


Method of producing alternating ether siloxane copolymers Patent

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