CA1123451A - Structurally regulated polyphosphazene copolymers - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
This invention relates to polyphosphazenes which have an at least partially regulated structure corresponding to the formula:
?N3P3(C1)5(OR1)?n (I) where n is greater than 2, and where R1 is phenyl or substituted phenyl. This invention further relates to copolymers, derived from the above polymers (I), which correspond to the formula:
?N3P3(ORl)(OR2)5?n (II) where R1 is phenyl or substituted phenyl and where R2 is different than R1 and is an alkyl or substituted alkyl radical or a phenyl or substituted phenyl radical.
These polymers are prepared by polymerizing cyclic triphosphazenes of the formula:

(III) to form the polymers (I) which, in turn, are reacted to re-place the chlorine with organic radicals to form polymers (II).
The polymers (II) can be formed by chemical blowing agents to form fire retardant articles. These polymers have fire retardant properties and evolve little or no smoke when exposed to an open flame.

Description

l~.Z345~l ~
STATE OF THE ART

A number of polyphosphazene copolymers are known in the art, but they are all characterized by the presence o~ random repeating units which can be characterized by the random structures ~ ~`
- t P = N ~ P = N ~ t P = N ~ ~ ~

where A and B are different. A number of such copolymers , .
are described in U. S. Patents 3,271,330; 3,370,020, 3,370,026;
3,443,913; 3,515,68~; 3,700,629; 3,702,833; 3,732,175;
3,8a4,983; 3,856,712; 3,856,713; 3,869,058; 3,883,451; 3,888,799 and 3,888,800.
Attempts have been made in the prior art to ;~
polymerize the cyclic compounds N3P3(OC6H5)6 and N3P3~C6H5) without success (see Allcock, "Phosphorous-Nitrogen Compounds", Academic Press, 1972, pgs. 323-328). The polymerization of of N3P3FsC6Hs has been accomplished (see Allcock et al, Macromolecules, 8 337 (1975).
The polymers (I) of the present invention vary ..
markedly from the polymer ~NPC12]n (see Allcock et al U. S. ;
3,370,020), in that one out of every three repeating units is a ~NPCl(ORl)~ unit rather than a ~NPC12~ unit. Likewise, `~
the polylller (II) has a regularly occurring ~I~P(ORl)(OR2)~
unit, as opposed to the totally random distribution in the prior art copolymers.
DESCRIPTIO~1 OF THE INVENTION
It has now been discovered that cyclic polyphos-.~ .; .

- 2 ~

'1 ~ 3451 phazenes of the formula:

Cl Cl C ~ ~ 1~ Cl (III) Cl'' ~ N ~ \ OR
where Rl is ~`~J~ ~
when R3s, when present, are located in the meta or para positions on the phenoxy ring, where x is 0 to 3; preferably 0 to 1 ~;
(where x is 1, R3 preferably is in the para position); and where R3 is independently, lower (e.g. C1-C10) linear or branched alkyl, such as methyl, ethyl, n-butyl, sec. butyl or tert. butyl, 2-ethyl hexyl and n-nonyl; lower (e.g., Cl-C4) linear or branched alkoxy, such as methoxy, ethoxy, butoxy; halo (e.g., chloro, bromo or fluoro), cyano, or ~;
nitro, or substit~ted alkyl or alkoxy (e.g., nitro, cyano, halo or lower al~oxy) can be polymerized to form polymers having re~eating units corresponding to the formula~
~N3p3(cl)s(oR )~n (I) ~;
where n is- greater than about 2 to about 600 or higher and where Rl is defined as above.
The polymers (I) can be further reacted to form homopolymers or copolymers having repeating units corres~
ponding to the formula:

~N3P3(ORl)(OR2)5~n (II) where n and Rl are defined as above and where R2 is the same ~;-'' '"',

- 3 - ;
`" ' 1.23~51 : .
as Rl or is different than Rl and is lower ~e.g., Cl-C10) linear or branched alkyl, lower alkaryl, substituted lower alkyl, such as lo~er alkoxy, halo, cyano or nitro substituted alXyl or -{C~R :s ~

.. . ~. .
where ~4s, when present, are substi~uted on any sterically permissible position on the phenoxy ring, preferably meta and para, where z is O to 3; preferably O to l; (where z is 1, R4 preferably is in the para position~ and where R4 is - independently,-lower linear or branched alkyl, lower linear ~-or branched alkoxy, halo (e.g., chlorine, bromine or fluorine), ~ nitro, cyano or substituted alkyl or alkoxyl (e.g., nitxo, -~j cyano, halo or lower alkoxy substituted).
Examples of oR2 include methoxy, ethoxy, propoxy n-butoxy, sec. butoxy, tert. butoxy, octyl, phenoxy, tolyloxyr -~
1 xylyloxy, benzy1,phenethylo~Yy~ chloro, bromo, methoxyphenoxy, `~
., . ;.
propoxyphenoxy, p-nitrophenoxy~ OCH2CF3~ O~H2C3F7~ OCH2c3F6cF2 2,2,33-tetrafluoropropoxy, 3,4-dichlorophenoxy, 4-bromophenoxy, ~`~
~ 2-chloroethylphenoxy, 2-chloroethoxyphenoxy and the like.
:~ It is to be understood that while it is presently preferred that all Rls are the same and all R2s are the same the Rl can be mixed and the R2 can be mixed. The mixtures may be mixtures of different substituents or mixtures of ~;
different positional isomers~ In preparing specific pol~mers ~;
steric hindrance must be considered. For example, one skilled in the art readily will recognize that steric i hindrance will dictate the propriety of using relatively ~

:.
. . , ,::

- 4 - ;~

.
'' ' '',~", .
. ~

.2345~L `

bulky groups in the orthoposition on the phenoxy ring since as set forth hereinafter the R2 is provided by reacting a substituted metal phenoxide with a chlorine atom on a phosphorus atom. Desirably, groups which sterically in-hibit such a substitution reaction should be avoided. Absent the foregoing proviso, the selection of the various R2s will be apparent to anyone skilled in the art based upon this dis-closure. ;
The repeating units of the polymer (II) can be ....
represented by the formulas:

oRl ¦ (VI) QR2 ¦ ~V) oR2 ~ and1 oR2=N ~

L n ~ 2n where the ratio of unit IV to unit V is 1:2, since the repeating unit is derived from ring opening of the tri-phosphazene (III). For example, typical polymer segments would ~-be one or more of _ _ ' .' .
I Rl lo~2 oR2 1 ... ~ . . .
_ - P =N- - P =N - P =N ~ ~ -~ bR2 oR2 oR2 _ _In j R2 ORl OR 2 . ~ .
_ _ p =~ P =~1 P =M , or oR2 1R2 1R2 OR2 o~2 OR
I ! I
~ ORZ oR2 I R2 J

~-, :~'

- 5 -~.~I.Z3~5~

The above described polymers (II), as well as `~
those containing reactive sites designated as W below, may be crosslinked and/or cured at moderate temperatures (for example, 200-350F.) by the use of free radical initiators, for example, peroxides, using conventional amounts, techniques and processing equipment.
The copolymers of this invention may contain small amounts of.substituents W, which randomly replace a portion of the -oR2 groups, i.e. units such as 1 p = ~ I ~R
lw w wnere W represents a group capable of a crosslinking chemical reaction such as an olefinically unsaturated, preferably ethylenically unsaturated monovalent radical COntalning a :~
group capable of fur~her reaction at relatively moderate : ~
temperatures, the ratio of W:RlfR2 being less than about -1:5. Examples of W are -OCH=CH2; -OR5CH=CHl; -O-IC=CH2;

-OR5CF=CF2 and similar groups wnich contain unsaturation, where R5 and R6 are aliphatic or aromatic radical, prefer- :

abLy R6 is -CH~-. These groups are capable of further re-action at moderate-temperatures (for example, 200-350F.) in the presence of free radical initiators, conventional sulfur curing or vulcanizing additives known in the rubber art or other reagents, often even in the absence of accelerators, :
using conventional techniques and processing equipment.
Examples of free radical initiations include benzoyl peroxide,

- 6 -2~51 bis(2,4-dichlorobenzoyl peroxide), di-tert-butyl peroxide, dicumyl peroxide, 2,5-dimethyl~2,5-di-tert-butylperoxy)hexane, t-butyl perbenzoate, 2,5-dimethyl-2,5-di(tert-butylperoxy) hepyne-3, and 1,1-bis(tert-butylpero~y)-3,3,5-trimethylcyclo-hexane. Thus, the general peroxide classes which may be used for crosslinking include diacyl peroxides, peroxyesters, and dialkyl peroxides.
Examples of sulfur-type curing systems include vul-canizing agents such as sulfur, sulfur monochloride, selenium, tellurium, thiuram disulfides, p-quinone dioximes, poly-sulfide polymers, and alkyl phenol sulfides. The above vulcanizing agents may be used in conjunction with accelerators, such as aldehyde amines, thio carbamates, thiuram sulfides, guanidines, and thiazols, and accelerator activators, such as zinc oxide or fatty acids, e.g., stearic acid.
It is also possible to use as W in the above formulas, monovalent radicals represented by the formulas (11 -oSi(oR7)2R8 and other similar radicals which contain one or more reactive groups attached to silicon; (2) -OR9NR9H
and other radicals which contain reactive -NH linkages. In ;
these radicals R7, R8 and R9 each represent aliphatic, aroma.ic and acyl radicals. Like the groups above, these groups are capable of further reaction at moderate temperatures in the presence of compounds which effect crosslinking. The presence of a catalyst to achieve a cure is oftern desirable.
The introduction of groups such as W into polyphosphazene ~ ~;
polymers is shown in U. S. Patents 3,888,799; 3,702,833 and 3,844,983, The amount of W present in the copolymer, affects ~- 7 -.23~5~ J ;

the processability, smoke production, glass transition tem-perature and a number of other properties of the copolymers.
These ratios also affect the copolymer's ability to be foamed and the properties, such as the rigidity, of the resulting foams.
The cyclic polyphosphazenes (III) can be prepared, for example, by following the general reaction scheme taught by Dell et al, "Phosphorus Nitrogen Compounds Part XIII
Phenoxy and p-Bromophenoxy-Chlorocyclotriphosphazatrienes", J. Che~. Soc. (1965) 4070-4073.
Generally, the procedure comprises forming the sodium salt of the desired phenolic compound (HORl , where is defined as above) in a suitable solvent such as tetra-hydrofuran or dioxane. This phenoxide is then slowly added to the trimer, hexachlorocyclotriphosphazene in a suit-able solvent, as above, the reaction being conducted at low temperatures to retard side reactions. The use of significant amounts of solvent also promotes a uniform product. The product is then isolated. In a preferred isolation technique, a water immiscible solvent is substituted for tne reaction solvent and the solution is washed seriatim with dilute acid, dilute base and water to remove unreacted starting materials and by-products. The organic layer is then vacuum distilled.
There follows several examples showing the preparation ~ -of cyclic phosphazenes (III).

E~MPLE l . ~:
N3P 3C15 (OC 6~i 5 ) Sodium phenoxide was formed by reacting 8.0 parts ~Z3~51 of sodium with 44.0 parts of phenol in 1800 parts of tetra-hydrofuran.
120.0 parts of hexachlorocyclotriphosphazene was charged into a reactor together with 1000 parts of tetra-hydrofuran and the mixture cooled to -78C. To the stirred reactor, there ~as then added dropwise, over a three hour period, the previously prepared sodium phenoxide solution, while maintaining the temperature at -78C. until the addition was complete. The reaction mixture was then allowed to warm to room temperature. - ;
The reaction mixture was then worked up in the following manner: The solvent was evaporated and the re- ~ ;
sultant oil was dissolved in petroleum ether. The ether ~ `
solution was washed with 5gO aqueous hydrochloric acid, then 5~ aqueous sodium bicarbonate, followed by several washings with water. The petroleum ether was then evaporated and the resultant oil was vacuum distilled to obtain phenoxypenta- ~-chlorocyclotriphosphazene (b.p. 74C. at .07 Torr).~ `

Elemental Analysis: Theoretical - C 17.78, H 1.24, N 10.37, P 22.93; Found - C 17.65, ~ 1.24, N 10.44, P 22.88.
EXP~1PLE 2 N3P3Cls(OC6~l~ P F) - Sodium p-fluorophenoxide was formed by reacting 4 parts of sodium with 26.9 parts of p-fluorophenol in 900 parts of tetrahydrofuran.
60 parts of hexachlorocyclotriphosphazene were charged into a reactor together with S00 parts of tetra-hydrofuran and the mixture cooled at -78C. The previous-ly prepared sodium p-fluorophenoxide solution was added _ g _ dropwise and reactcd as in Example 1. The resultant product was worXed up as in Example 1 to yield p-fluoropheno~ypenta- -chlorocyclotriphosphazene (b.p. 107C. at .02 Torr).

Elemental J~nalysis: Theoretical - C 17.02, H 0.95, N 9.93, P 21.94; Found - C 17.36, H 1.00, N 9.86, P 21.85.

~XAMPL~ 3 ~ .
3 3 5 6 5 P ) Vsing sodium p-chlorophenoxide, p-chlorophenoxy-pentachlorocyclotriphosphazene was prepared following the procedure of Example 1 (b.p. 126C. at 0.25 Torr).

. Elemental Analysis: Theoretical - C 16.39, H 0.90, N 9.56, P 21.13; Found - C 16.34, H 0.82, N 9.42, P 21.05.

N3P3C15(OC6~4-P-CH3) : ~.

Using sodium p-methylphenoxide, p-methylphenoxy-; pentachlorocyclotriphosphazene is prepared following the procedure of Example 1 (b.p. 130C. at .05 Torr). .

Elemental Analysis: Theoretical - C 20.05, H 1.68, N 10.02 P 22.16; Found - C 20.18, H 1.69, N 10.08, P 22.09. ~: ~

E~MPLE 5 .`
- N3P3Cls(OC6H4-p-OCI~3) Using sodium p-methoxyphenoxide, p-methoxyphenoxy-pentachlorocyclotriphosphazene was prepared following the procedure of Example 1 (b.p. 121C. at .025 Torr) `::

Elemental Analysis: Theoretical - C 19.31, H 1.62, N 9.65, P 21.3-~; Found - C L9.58, H 1.79, N 9.67, P 21.43.
In a manner similar to the ahove teachings or using variants obvious to those skilled in the art, other cyclic trimers (III) can be prepared.

. ..... ~ ~ ,:

.Z3g51 The polymers ~I) are prepared by thermally polyme~-lzing the cyclic t~iphosphazenes by heating them at a ~:
temperature and for a length o~ time ranging ~rom about 200C.
~or 72 hours to 300C. for 30 minutes. That is to say the compoun~ls are heated to a ter~lperature ranging from ab~ut 200OC, to about 300C. ~or from about 3~ mlnutes to 72 hours, the higher temperatures necessitating shorter lontact `

times and the lower temperatures necessitating longer con-~act ti~es. The compounds must be heated for such a length of time that only a minor amount of unreacted charge material remalns and a major amount of high polymer has been produced.
Such a result is generally achieved ~y following the con-ditions of temperature and contact time speciried ahove.
It is preferred that the thermal polymerization be carried out in the presence of an inert gas such as nitrosen, neon, argon or a vacuum, for example, about 10-2 Torr, inasmuch as the reaction proceeds very slowly in the ~`
presence-of air. The use of such a gas, however, is not critical. The presence of moisture is also-preferably -avoided. ~`
The polymerization process follows that taught ~;
for the polymerization of ~PC12~3, as described in ~. S.
. ; ~
3,370,020. ~-The polymers resulting from the thermal polymeriæa- ;;
tion process are in the form of a polymeric mixture of different polymers of different chain lengths. That is to say, the product of the thermal polymerization is a mixture of polymers having the formula (I) ~N3P3(cl)5(oRl)~n -- 11 -- , . .

~ ~ ~3451 where n ranges from about 2 to about 600 or higher. Fox example, the recovered media may contain minor amounts of a polymer where n is 2 and major amounts of polymer w~ere n is 600 or higher. The media may also contain polymers composed of from 3-599 or higher recurring units, the com-plete mixture of polymers may COnStltUte the starting ma-terial for Eorming the polymer (II).
The polymers (I) exhibit excellent elastomeric properties but display instability to atmospheric moisture.
- There follows several examples of the preparation - of polymers (I). These examples, as is true of all the `~
. .
e~amples herein, are exemplary and are not to be construed as limiting.

EX~MPLE 6 ~N3P3Cls(Oc6Hs)3n , ~.
A quantity of tl~e trimer of Example 1 was de~
Oxygenated with inert gas and sealed in a suitahle, thick~
walled reaction vessel at 10-2 Torr and heated at 250C.
for 15 hours. Polymerization was terminated at this time since a glass ball,one-half inch in diameter, ceased to flow due to the increased viscosity of the molten mass, when the vessel was inverted termination was effected by cooling the vessel to room temperature. The resultant polymer had a Tg of -49.1C.

Elemental Analysis: Found (%) - C 17.62, H 1.20, N 10.28, P 23.12.
E~AMPLE 7 ~N3p3cls(oc6H4-p-~)~n In the same manner as Example 6, the trimer of ";, .23451 Example 2 was thermally polymerized at 250C. for 8 hours.
The resultant polymer had a Tg of -47.6C.
EXAMP~E 8 fN3P3Cl5(Oc6lI4-p-cl)~n `~
:
In the same manner as Example 6, the trimer of Example 3 was thermally polymerized at 250C. for 10 hours.
The resultant polymer had a Tg of -39.3C.

Elemental Analysis: Found - C 16.29, H 0.82, N 9.49, P 21.05.

~N3P3Cls(Oc6H4-p-c~3)~n In the same manner as Example 6, the trimer of Example 4 was thermally polymerized at 250C. for 18 hours.
The resultant polymer had a Tg of -44.2C.

~N3P3cls(Oc6~4-p-ocH3)~n In the same manner as Example 6, the trimer of Example 5 was thermally polymerized at 250C. for 6 hours. ~ -The resultant polymer had a Tg of -43.7C. -The polymers (II) are formed in a process which comprises treating the polymer mixture (I) resulting from ;-the t;~ermal polymerization step with a mixture of compounds having the formulas ~(OR2)V and if desired, M(~)v~
wherein M is lithi~n, sodium, potassium, magnesium or cal-cium, v is equal to the valence of metal M, and -oR2 and ~ ;~
are as specified above.
The polymer mixture is reacted with the mixture '' :' ` ?
- ~ 23ss~

of metal compounds at a temperature and a length of time ranging from about 25C. for 7 days to about 200C~ for 3 hours.
- Again, as in regard to the polymerization step mentioned above, the polymer mixture is reacted with the alkali or alXaline earth metal compounds at a temperature ranging from about 25C. to about 200C. for from about 3 hours to 7 days, the lower temperatures necessitating the longer reaction times and the higller temperatures allowing shorter reaction times. These conditions are, of course, utilized in order to obtain the most complete reaction possible,-i.e., in order to insure the complete conversion of the chlorine atoms in the polymer mixture to the corresponding ester of the alkali or alkaline earth starting materials.
The above esterification step is carried out in :the presence of a solvent. The solvent employed in the esterification step must have a relatlvely high boiling point (e.g., about 115C. or higher) and should be a solvent for both the polymer and the alkali or alkaline earth metal compounds In addition, the solvent must be sub-stantially anhydrous, i.e., there must be no more water in the solvent or metal compounds than will result in more than 1%, by weight, of water in the reaction mixture. The pre-vention of water in the system is necessary in order to in-hibit the reaction of the available chlorine atoms in the polymer therewith. Examples of suitable solvents include diglyme, triglyme, tetraglyme, toluene and xylene. The ..

amount of solvent employed is not critical and any am~unt sufficient to solubilize the chloride polymer mixture ;
can be employed. Either the polymer mixture or the alkaline earth (or alkali) metal compounds may be used as a solvent solution thereof in an inert, organic solvent. It is preferred, however, that at least one of the charge materials be used as a solution in a compound which is a solvent for the polymeric mixture.
The amount of alkali metal or alkaline earth metal compound or compounds employed should be at least about stoichiometrically equivalent to the number of available chlorine atoms in-the polymer mixture. However, it is preferred that an excess of the metal compound be employed ` -in order to assure complete reaction of all the available chlorine atoms. Where a mixture of metal compounds is em-ployed, generally, the ratio of the individual alkali metal or alkaline earth metal compounds in the combined mixture governs the ratio of the groups attached to the polymer backbone. However, those skilled in the art readily will ~ -appreciate that the nature and, more particularly, the steric configuration of the metal compounds employed may effect their relative reactivity. Accordingly, the ratio ~ ~ -mixed R2s in the esterified product, if necessary may be controlled by employing a stoichiometric excess of the slower reacting metal compound.
Examples of alkali or alkaline earth metal compounds which are useful in the process of the present invention in-clude .. . . .

.^~ ; ` `~
.2;3451 sodium phenoxide potassium phenoxide sodium p-methoxyphenoxide sodium o-methoxyphenoxide sodium m-methoxyphenoxide lithium p-methoxyphenoxide -~
lithium o-methoxyphenoxide lithium m-methoxyphenoxide potassium p-methoxyphenoxide potassium o-methoxyphenoxide potassium m-methoxyphenoxide magnesium p-methoxyphenoxide magnesium o-methoxyphenoxide magnesium m-methoxyphenoxide calcium p-methoxyphenoxide calcium o-methoxypllenoxide calcium m-methoxyphenoxide sodium p-ethoxyphenoxide ~.:
sodium o-ethoxhphenoxide sodium m-etho~yphenoxide potassium p-ethoxyphenoxide potassium o-ethoxyphenoxide potassium m-ethoxyphenoxide sodium p-n-butoxyphenxoide sodium m-n-~utoxyphenoxide lithium p-n-butoxyphenoxide lithium m-n-butoxyphenoxide potassium p-n-butoxyphenoxide potassium m-n-butoxyphenoxide magnesium p-n-butoxyphenoxide ~nagensium m-n-butoxyphenoxide calcium p-n-butoxyphenoxide calcium m-n-butoxyphenoxide .
sodium p-n-propoxyphenoxide sodium o-n-propoxyphenoxide sodium m-n-propoxyphenoxide .
potassium p-n-propoxyphenoxide potassium o-n-propoxyphenoxide potassium m-n-propoxyphenoxide :.
sodium p-methylphenoxide ;: .
sodium o-methylphenoxide sodium m-methylphenoxide lithium p-methylphenoxide lithium o-methylphenoxide lithium m-methylphenoxide sodium p-ethylphenoxide :;
sodium o-ethylphenoxide :' sodium m-ethylphenoxide potassium p-n-propylphenoxide potassium o-n-propylphenoxide potassium m-n-propylphenoxide . . ,~
magnesium p-n-propylphenoxide -~
sodium p-isopropylphenoxide sodium o-isopropylphenoxide : ~i sodium m-isopropylphenoxide ca:Lcium p-isopropylphenoxide ca:lcium o-isopropylphenoxide ~ :

. . .

,:

- ~ . .

.

1~.2345~
:.
calcium m-isGpropylphenoxide sodium p-sec butylphenoxide sodium m-sec butylphenoxide llthium p-sec l~utylphenoxide lithium m-sec butylphenoxide llthium p-tert. butylphenoxide lithium m-tert. butylphenoxide potassium p-tert~ butylphenoxide . -potassium m-tert. butylphenoxide .
sodium p-tert. butylphenoxide sodium m-tert. butylphenoxide -sodium propeneoxide - sodium p-nonylphenoxide sodium m-nonylphenoxide sodium o-nonylphenoxide sodium 2-methyl-2-propeneoxide ,.``
potassium buteneoxide and the like.
This process results in the production of a polymer mixture having-the-formula (II).
The polymeric reaction mixture resulting from this reaction or esterification step is then treated to remove the salt which results upon reaction of the chlorine atoms of the starting polymer mixture with the metal of the -alkali or alkaline earth metal compounds. The salt can be removed by merely precipitating it out and filtering, or it may be removed by any other applicable method, such as by washing the reaction mixture with water after neutralization thereof with, for example, an acid such as hydrochloric acid.
The next step in the process comprises fractionally precipitating the polymeric material to separate out the high polymer from the low polymer and any unreacted trimer. , The fractional precipitation is achieved by the,preferably dropwise, addition of the esterified polymer mixture to a material which is a non-solvent for the high polymer an~ 2 ~ .
solvent for the low polymer and unreacted trimer. That is to say, any material which is a nonsolvent for the poly~ers wherein n is higher than 350 and a solvent for the remaining -~

low polymers may be used to fractionally precipitate the ; ~ ~
'", ';'' ~ 17~_ ~

--~ ) 2345~

desired poly~ers. Examples of materials which can be used for this purpose include hexane, diethyl ether, carbon tetrachloride, chloroform, dio~ane methanol, water and the like. The fractional precipitation of the esterified polymeric mixture generally should be carried out at least twice and preferably at least four times in order to remove as much of the lo~ polymer from the polymer mixture as possible.
The precipitation may be conducted at any temperature, however, it is preferred that room temperature be employed.
The novel high molecular weight copolymer mixture may then be recovered by filtration, centrifugation, decantation or the like.
There follows several examples of the preparation of polymers (II).
E,Y~MPLE 11 ~NP(OC6Hs)~n - ~ . . ~' .
An anhydrous toluene solution of the polymer formed in E.Yample 6, containing 31.2 parts of the polymer, was added to an anhydrous diglyme-benzene solution of 5~.9 parts of sodium phenoxide at a temperature of 95C. with constant stirring. After the addition, benzene was dis-tilled from the reaction mixture until a temperature of 115-116C. was attained. The reaction was then heated to reflux for 60-65 hours. At the end of this time, the resultant polymer was precipitated by pouring the reaction mixture into an excess of methyl alcohol. The polymer was stirred in the methyl alcohol for 24 hours. ~ext, the polymer was added to a large quantity of water and stlrred ~`

an additional 24 hours. The polymer was then separated and :

Z34~

dried. The resultant homopolymer was a semicrystalline solid having a glass transition temperature (Tg) of -4.76C.
The polymer was soluble in benzene, tetrahydrofuran (THF) and dimethylformamide (DMF). Films cast from THF were tough and opaque. The films did not burn and were water repellent.

Elemental Analysis. ~heoretical - C 62.34, H 4.36, ll 6.06, P-13.40; Found - C 62.10, H 4.36, N 5.97, P 13.69.
EXP~IPLE 12 ~NPtOC6H4~P~Cl)2~n . .
The procedure of Example 11 was followed, except that lS.0 parts of the polymer-of Example 8 were reacted with 30.8 parts of sodium p-chlorophenoxide. The resultant ~
homopolymer (79% yield) was a semicrystalline solid having ~ ~-a Tg of -1.54C. The polymer was soluble in benzene, THF, Dl~F and chloroform. Films cast from the THF were `
tough and opaque. The films did not burn and were water repellent.

Elemental Analysis: Theoretical - C 48.18, ~ 2.70, N 4.68, ~ -P 10.36; Found - C 47.90, H 2.63, N 4.49, P 10.28.

~3P3(oc6~5)(oc6H4-p-cl)5~n - The procedure of Example 11 was followed, except that 16.5 parts of the polymer of Example 6 were react~d with 37.1 parts of sodium p-chlorophenoxide. The resultant copolymer (56~ yield) was a solid soluble in benzene, THF
and DMF. Films cast from THF were tough and opaque.
The films did not burn and were water repellent.

Elemental Analysis: - Theoretical - C 64.48, H 5.28, N 5.50, P 72.17; Found - C 64.34, H 5.22, N 5.42, P 12.30.

. ' ' ', ' ' ~ , . .. .

L1.23~5~

~N3p3(oc6Hs)(oc6~ p-cH3)5~n The procedure of E~ample 11 was followed,except that 14.1 parts of the polymer of Example 6 were reacted ~ ;~
wlth 27.3 parts of sodium p-methylphenoxide. The resultant polymer (40~ yield) was a solid, soluble in benzene, THF
and D.~F. Films cast from THF were-tough and transparent.
.
The films did not burn and were water repellent.

Elemental Analysis: Theoretical - C 64.48, ~I 5.28, N 5.50, P 12.17; Found - C 64.34, H 5.22, N 5.42, P 12.30.

~N3P3~OC6H4-P-F)(O~6H4 P CH3)5~n The procedure of Example 11 was followed, except that 18.9 parts of the polymer of Example 7 were reacted with 35.3 parts of sodium p-methylphenoxide. The resultant polymer (70~ yield) was a solid with a Tg of ~0.08C, soluble in ~enzene, THF and D~F. Films, cast from THF, were tough and transparent, did not burn, and were water ` "'!~
repellent. `

Elemental Analysis: Theoretical - C 63.00, H 5.03, N 5.37, -~
P 11.89; Found - C 62.91, H 5.18, N 5.26, P 12.01.

~13P3(oc6H4-p-cl)(oc6H4-p-cH3)5~n The procedure of Example 11 was ~ollowed, except that 15.0 parts of the polymer of ~xample 8 were reacted with 26.6 parts of sodium p-methylphenoxide. The resultant polymer (72~ yield) was a solid with a Tg of -3.65C., soluble in ben~ene, THF and D~. Films, cast from THF, were tough and transparent, did not burn and were water repellent. ~

~ ' `~
:, ' ,:

45~

Elemental Analysis: Theoretical - C 61.93, H 4.56, N 5.28, P 11.69; Found - C 61.83, H 4.72, N 5.18, P 11.52.

~,.
~N3P3(OC6H4-p-CH3) (c~,H4-p-cl)5~n The procedure of E~ample 11 was followed, except that ~ ~;
20.6 parts of the polymer of Example 9 were reacted with 44.1 ~ ~ -parts of sodium p-chlorophenoxide. The resultant ~olymer (41%
yield) was a solid with a Tg Gf +2.06C., soluble in benzene, ;
THF and DMF. Films, cast from THF, did not burn and were water repellant.
Elemental Analysis: Theoretical - C 50.51, H 3.09, N 4.78 -P 10.56; Found - C ',0.32, H 3.05, N 4.77, P 10.78.

;, ~N3P3(Oc6H5) toC6H4-4 CH3j5~n A solution of 15.5 parts of [N3P3C15(OC6H5)]
. ~
polymer in 200 parts of anhydrous toluene was added over a 1.5 hour period to a stirred solution of sodium p-methoxy-phenoxide at 90C. The sodium aryloxide solution was prepared by the reaction of 28.3 parts of p-methoxyphenol with 5.1 parts ;~
of sodium in 300 parts of anhydrous bis-(2-methoxyethyl) ether ;i-and 100 parts of dry benzene. After the addition, benzene was distilled until a temperature of 115-116C. was attained. The reaction mixture was then hezted at 115-116C. for 60-70 hours ~;-with constant stirring. The polymer was precipitated into a large excess of methanol and washed in methanol for 24 hours.
It was removed from the methanol, exhaustively washed with distilled water, and dried. The product is a colorless, stiff elastomer. ~ `~
:~
~' ' . ~ .

. .

5~

E~A~iPLE 19 ~2~3P3(OC6Hs)(OC6H4~4~Cl)5~n . .
A solution of 16.5 g (~.205 equiv.) of [N3P3C15(OC6H5)]n polymer in 300 ml of anhydrous toluene was added over a 1.5 hour period to a stirred solution of sodium p-chlorophenoxide at 90C. The sodium aryloxide solution was prepared by the reaction of 31.6 g (0.246 mole) of p-chlorophenol ~ith 5.6 g (0.241 mole) of sodium in 300 ml of anhydrous bis-(2-methoxyethyl)ether and 100 ml of dry benzene. After the addition, benzene was distilled until a temperature of 115-116C. was attained. The reaction mixture was then heated at lls-il6C. for 60-70 hours with constant stirring.
The polymer was precipitated into a large excess of methanol and washed in methanol for 24 hours. It was removed from the methanol, exhaustively washed with distilled water, and dried. The product is a colorless, fibrous material.
Following similar procedures, other homopolymers and copolymers, such as described above, can be prepared.
The novel polymers (II) of this invention, as mentioned above, are very thermally stable. The mixtures ;
are soluble in specific organic solvents such as tetrahydroluran, benzene, xylene,toluene, dimethylformamide and the like and can be formed into films from solutions of the copolymers : . ,.. ~,. . .
by evaporation of the solvent. The polymers are water resistant at room temperature and do not undergo hydrolysis at high temperatures. The polymers may be used to prepare films, fibers~coatings~ molding compositions and the like.
They may be blended with such additives as antioxidants, ultra~
violet light absorbers, lubricants, plasticizers, dyes, . ~, ,.
.

- 22 - ~

,39~5~

pi~ments, fillers such as litharge, ~agnesia, calcium carbonate, furnace black, alumina trihydrate and hydrated silicas, other resins, etc., without detracting from the scope of the present ~
i nventiOn . . . ~:' The polymers may be used to prepare foamed products which exhibit excellent fire retardance and in some cases produce low smoke levels, or essentially no smoke when heated in an open flame. The foamed products may be prepared from filled or unfilled formulations using conventional foam techniques with chemical blowing agents, i.e. chemical compounds stable at original room temperature which decompose - ;~
or interact at elevated temperatures to provide a cellular foam. Suitable chemical blowing agents include:

Blowing Agent Effective Temperature Range C.

Azobisisobutyronitrile -105-120 ~ ~;
Azo dicarbonamide(l,l-azobisform-amide) 100-200 Benzenesulfonyl hydrazide 95-100 N,N'-dinitroso-Nt`L~'-dimethyl tere-phthalamide Dinitrosopentametnylenetetramine 130-150 Ammonium carbonate 58 p,pl-oxybis-(benzenesulfonyl-hydrazide) 100-200 Diazoaminobenzene 84 Urea-biuret mixture 90-140 `~
2,2'-azo-isobuty ronitrile 90-140 Azohexahydrobenzonitrile 90-140 Di;sobutylene 10 4,4'-diphenyl disulfonylazide 110-130.
Typical foamable formulations include:
J Phosphazene copolymer (e.g., ~N3p3(oc6Hs)(oc6H4-p-oc~I3)s]n ,. . .
'~ ' , ,:

':

4~

100 parts Filler (e:g., alumina trihydrate) 0-100 phr Stabilizer (e.g., magnesium oxide) 2.5-10 phr Processin~ aid ~e.g., zinc stearate)~ 2.5-10 phr Plasticizer resin (e.g., Cumar P-10 ~
coumarone indene resin)0-50 phr Blowing agent (e.g~, l,l'-azobisformamide) 10-50 phr Activator (e.g., oil-treated urea) 10-40 phr Peroxide curing agent (e.g., 2,5-dimethyl-2,5-di(t-butylperoxy) hexane) 2.5-10 phr Peroxide curing agent (e.g., benzoyl peroxide 2.5-10 phr ~hile the above are preferred formulation guidelines, obviously some or all of the adjuvants may be omitted, replaced by other functionally equivalent materials,- or the proportiOns varied, within the skill of the art of the foam formulator.
In one s~itable process, the foamable ingredients are hlended together to form a homogeneous mass; for example, a nomogeneous film or sheet can be formed on a 2-roller mill, preferably with one roll at ambient temperature and the other at moderately elevated temperature, for example, 100-120F.
The homogeneous foamable mass can then be heated, to provide a foamed structure; for example, by using a mixture of a curing agent having a relatively low initiating temperature, -~
such as benzoyl peroxide, and a curing agent having a relativeIy high initiating temperature, such as 2,5-dimethyl-2,5-di(t-bu.ylperoxy) he~ane, and partially pre-curing in a closed mold for about 6-30 minutes at 200-250F., followed by free expansion for 30-60 minutes at 300-350F. In the -alternative, the foaming may he accomplished by heating the foa~able mass for 30-60 minutes at 300-350F. using a high temperature or low temperature curing agent, either singly or in combination. One benefit of utilizing the "partial ~ ;;

- 24 - ~;

345~
:;
pre-cure" foaming technique is that an increase in the molecular weight of the foamable polymer prior to the foaming step enables better control of pore size and pore uniformity in the foaming step. The extent of "pre-cure"
desired is dependent upon the ultimate foam characteristics desired. The desired foaming temperature is dependent on the nature of the blowing agent and the crosslinkers present.
The time of heating is dependent on the size and shape of the mass being foamed. The resultant foams are generally light tan to yellowish in appearance, and vary from flexi-ble to semirigid, depending upon the glass transition temperature of the copolymer employed in the foam formu-lation, that is to say, the lower the glass transition of the polymer the more flexible will be the foam produced therefrom. As indicated, inert, reinforcing or other fillers such as alumina trihydrate, hydrated silicas or calcium carbonate can be added to the polymer foams and the presence of these and other conventional additives should in no way be construed as falling outside the scope of this invention Preparation of Foamed t~3P3~OC6H5)(OC6H4~P~OcH3)53n -~
To 100 parts of the copolymer ~N3P3(OC6Hs)(OC6H4 p OCH3)s~n , ~
prepared in accordance with Example 20, there were added ~ ;
100 parts of alumina trihydrate, 5 parts of magnesium o.~ide, 5 parts of zinc stearate, 3 parts of &UMAR P-l (a coumarone-indene resin), 30 parts of Celoyen AZ (l,l'azobisformamide), 23 parts of BIK-O ~an oil-treated urea), 5 parts of ~ ;
;~' ~.~''' _ ~5- ~ :';''' ' ~; ~

~ %3~1 2,5-dimethyl-2,5-di(tert.-butylperoxy)hexane, and 5 parts of benzoyl peroxide (78% active, wet with water). The above ingredients were milled to insure homogeneous mixing of all materials. This mi~ was then free blown at 325-350F.
for 10 minutes. The resultant flexible foam was light tan in color with a uniform small cellular structure. There was no evidence of delaminatlon or slde splits. A piece of the foamed material when heated in a Bunsen burner flame evolved only a very slight trace of smoke. The sample did not burn when removed from the burner flame. Thus, it would not support combustLon and was rated as non-burning.`~ `
Also, as mentioned above, the polymers of this invention can be crosslinked at moderate temperatures ~y conventional free radical and/or sulf~r curing techniques when minor amounts of unsaturated groups W are present in ~`
the polymer backbone. The ability of these polymers to be cured at temperatures below about 350F. makes them particularly useful as potting and encapsulation compounds, -~-sealants, coatings and the like. These polymers are also useful for preparing crosslinked foams which exhi~it signifi-cantly increased tensile strengths over uncured foams. These polymers are often crosslinked in the presence of inert, reinforcing or other fillers and the presence of these and other conventional additives are deemed to be within the scope of this invention.
',.

- 26 ~

.:

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A structurally regulated polyphosphazene copolymer represented by the general formula ?N3P3(OR1) (OR2)5?n where n is greater than about 2 to about 600 and where R1 represents wherein R3 is located in the meta or para positions on the phenoxy ring, and represents lower alkyl, lower alkoxy, halo, cyano, nitro, substituted lower alkyl or substituted lower alkoxy and where R2 and R1 are different and represent lower alkyl, lower alkaryl, substituted lower alkyl or where z is 0 to 3 and where R4 represents lower alky1, lower alkoxy, nitro, cyano, halo, substituted lower alkyl or sub-stituted lower alkoxy wherein the substituents are nitro, cyano, halo or lower alkoxy and x is 0 to 3.

2 . A copolymer, as in Claim 1, where both OR1 and OR2 are phenoxy or substituted phenoxy groups.

3 . A copolymer as in Claim 2, where the substituted phenoxy is an alkyl or alkoxy substituted phenoxy group.

4. A copolymer as in Claim 1, where a portion of the OR2 groups are replaced by W which represents a group capable of a crosslinking chemical reaction and is -OCH=CH2; -OR5CH=CH2;
OC(R6)=CH2 or -OR5CF=CF2 wherein R5 and R6 represent an aliphatic or aromatic radical, the ratio of W:R1+R2 being less than about 1:5.

5. A copolymer, as in Claim 4 , where W is an ethylenically unsaturated monovalent radical.

6. A method of forming a structurally regulated polyphosphazene copolymer which comprises reacting a polymer represented by the general formula ?N3P3(C15)(OR1)?n with at least about a stoichiometric equivalent of one alkali or alkaline earth metal compound of the formula M(OR2)v where M is lithium, sodium, potassium, magnesium or calcium, v is the valence of the metal M, where n is greater than about 2 to about 600, where R1 represents wherein R3 is located in the meta or para positions on the phenoxy ring, and represents lower alkyl, lower alkoxy, halo, cyano, nitro, substituted lower alkyl or substituted lower alkoxy, and where R2 and R1 are different and represent lower alkyl, lower alkaryl, substituted lower alkyl or where z is 0 to 3 and where R4 represents lower alkyl, lower alkoxy, nitro, cyano, halo, substituted lower alkyl or substituted lower alkoxy wherein the substituents are nitro, cyano, halo, or lower alkoxy and x is 0 to 3.

7 . A method, as in Claim 6 , where both OR1 and OR2 are phenoxy or substituted phenoxy groups.

8 . A method, as in Claim 7 , where the substituted phenoxy is an alkyl or alkoxy substituted phenoxy group.

9 . A method of forming a structurally regulated polyphosphazene homopolymer which comprises reacting a polymer represented by the general formula ?N3P3(C1)5(OR1)?n with at least about a stoichiometric equivalent of an alkali or alkaline earth metal compound of the formula M(OR1)v where M is lithium, sodium, potassium, magnesium or calcium, v is the valence of the metal M, where n is greater than about 2 to about 600, and where R1 represents wherein R3 is located in the meta or para positions on ths phenoxy ring, and represents lower alkyl, lower alkoxy, halo, cyano, nitro, substituted lower alkyl or substituted lower alkoxy wherein the substituents are nitro, cyano, halo, or lower alkoxy and x is 0 to 3.

10 . A method, as in Claim 9, where a portion or M(OR1)v is replaced by M(OW)V where W is a group capable of a crosslinking chemical reaction and is -OCH=CH2; -OR5CH=CH2;
OC(R6)=CH2 or -OR5CF-CF2 wherein R5 and R6 represent an aliphatic or aromatic radical, the ratio of W:R1 being less than about 1:5.

11. A foamed cellular article comprising a structurally regulated polyphosphazene copolymer represented by the general formula ?N3P3(OR1)(OR2)5?n where n is greater than about 2 to about 600 and where R1 represents wherein R3 is located in the meta or para positions on the phenoxy ring, and represents lower alkyl, lower alkoxy, halo, cyano, nitro, substituted lower alkyl or substituted lower alkoxy, and where R2 and R1 are different and represent lower alkyl, lower alkaryl, substituted lower alkyl or where z is 0 to 3 and where R4 represents lower alkyl, lower alkoxy, nitro, cyano, halo, substituted lower alkyl or substituted lower alkoxy wherein the substituents are nitro, cyano, halo, or lower alkoxy and x is 0 to 3.

12. A cellular article, as in Claim 11, where both OR1 and OR2 are phenoxy or substituted phenoxy groups.

13. A cellular article, as in Claim 11, where the substituted phenoxy is an alkyl or alkoxy substituted group.

14 . A cellular article, as in Claim 11, where the polyphosphazene foamed contains W which represents groups capable of a crosslinking chemical reaction and is -OCH-CH2;
-OR5CH=CH2; OC(R6)=CH2 or -OR5CF=CF2 wherein R5 and R6 represent an aliphatic or aromatic radical, the ratio of W:R1+R2 being less than about 1:5.