GB1597698A - Poly (organophosphazenes) with chromophores as substituent groups - Google Patents

Description

(54) POLY(ORGANOPHOSPHAZENES) WITH CHROMOPHORES AS SUBSTITUENT GROUPS (71) We, THE FIRESTONE TIRE AND RUBBER COMPANY, of 1200 Firestone Parkway, Akron, Ohio, United States of America, a Corporation organised and existing under the laws of the State of Ohio, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention is concerned with novel poly(organophosphazenes) characterized by the presence of chromophoric groups. These groups may be covalently bound to the phosphazene polymers; or, if the chromophores are sufficiently acidic they may be ionically bound to the polymer so as to form acid addition salts. The polymers of the invention are useful for a wide variety of purposes where it is desirable to add color to the known advantageous chemical and physical properties of polyphosphazenes. They may be used therefore as colored films, fibers, food colorants and for a large number of other purposes.

According to the invention there is provided a poly(organophosphazenes) containing at least some units of formula: or of formula

wherein X is a chromophoric group, R is an organo substituent, the number of said units is from 250 to 20,000 and the ratio X:R from 1:1 to 1:15,000.

It will be seen that in units of the first formula the chromophore is covalently bound to the polymer backbone, and in units of the second formula it is electrovalently bound to constitute an acid addition salt.

The ratio of chromophore groups to organo groups may be e.g. 1:3 or 1:4. The ratio may be as high as 1:1 for the preparation of highly colored products.

However, if the number of chromophoric groups becomes too large, it may adversely affect the desirable properties of the polymer. The ratio may be as low as 1:15,000 for the production of slightly tinted products e.g. filters.

While any of a large number of organo substituents are possible, the preferred substituents are aryloxy wherein the aryl group is phenyl or substituted phenyl: alkoxy wherein the alkyl group contains up to five carbon atoms: alkyl-, dialkyl-, aryl- and diarylamino wherein aryl is phenyl or substituted phenyl and alkyl contains up to five carbon atoms: and fluorinated alkoxy groups e.g. trifluoro ethoxy. These substituents are preferred since the substituent is usually selected to impart some desirable property in the final product, and to do so as economically as possible. Generally, it is desirable to modify the water solubility of the product.

This can be readily achieved by selecting a substituent or group of substituents with hydrophobic or hydrophilic characteristics. The most water soluble polymers can be produced by selecting a lower alkylamino substituent e.g. methylamino or ethylamino. Water resistance is imparted in the final product by utilizing a trifluoroethoxy group.

Electropositive organo groups which supply electrons to the nitrogen atom of the polymer will enhance its basicity and help to stabilize the product. The preferred electron supplying groups are those which bind to the polymer through oxygen or nitrogen, and include, for example, methoxy, ethoxy, propoxy, butoxy, isobutoxy, methylamino, ethylamino, propylamino, butylamino, phenylamino, and piperidino.

It is not essential that all of the organo groups be identical. Special properties can be built into the products of the invention by forming them to contain two or more organo groups, for example, methoxy and methylamino, ethoxy and diethylamino, or butylamino and methylamino.

As will be apparent to those skilled in the art, both acidic and basic chromophoric compounds can be used to produce compounds of Formula I by the choice of appropriate reactants and reaction conditions.

Polyphosphazenes are strongly basic. Therefore, compounds of Formula II are prepared by acid base reactions between the polymer and an acidic chromophoric compound. The latter compound may contain an hydroxyl group rendered strongly acidic due to the structure of the balance of the molecule, or it may contain a characteristically acid group such as a carboxyl or sulfonic group.

Quite clearly, the range of chromophoric groups which can be bound either covalently or electrovalently to the polymer substrate is enormous. These include chromophores from all of the usual classifications, including such dyes as azo, nitro, ketone amine, anthraquinone, acridine, triphenylmethane, oxazine, phthalocyanine, indigoid and sulfur.

A few specific dyes, mentioned by way of example only, which can be employed to prepare products of Formula I include: celliton yellow, celliton orange, golden yellow, golden orange I, celliton violet R, oil orange, para red, cellitazol ST, yellow AB, brown V, celliton fast yellow, martius yellow, auramine, sudan violet, sudan green, chrysaniline yellow, proflavin and fuchsine.

Specific dyes utilizable for the production of ionic compounds include, for example, amido naphthol brown, gallocyanine, chrysamine in the acid form, benzo fast yellow in acid form, direct orange, fast red, metanil yellow, victoria violet, biebrich scarlet, orange R and Rhodamine B.

All of the specific dyes mentioned are illustrated by formula in The Chemistry of Synthetic Dyes and Pigments, H. A. Lubs, Reinhold, 1955. This publication, as does the Colour Index, lists a large number of other chromophoric compounds which can be used to prepare products of this invention. Those skilled in the art from a consideration of the structures of the above named compounds coupled with the balance of this disclosure, especially the examples, would have no difficulty preparing hundreds of embodiments of this invention.

The following equations illustrate the preparation of typical types of compounds within the scope of Formula I of this invention. In the equations, Compounds I and II are known and prepared by known reactions, and X and R have the meanings assigned above.

Equation A Acid addition salts, as aforesaid are prepared by typical acid base reactions e.g. as illustrated by the following equations:

wherein X is a selected chromophoric group.

It will be noted from the above reactions that the molecular weight of the final polymers will depend upon the molecular weight of the original polyphosphazene reactant. The most useful compounds within the scope of this invention are those in which n is from 250 to 10,000. Although polymers in which n is appreciably less than 250 can be usefully employed for many purposes, it is usual that n is not markedly higher than 20,000.

The molecular weight range for the compounds of this invention will vary somewhat with the polymer and chromophore, but is generally from 100,000 to 4,000,000.

The products of the invention can be fabricated utilizing standard polymer processing techniques. Thus, for example, they can be cast as films from solution, they can be extruded or they can be molded. To utilize these techniques, it is best to avoid cross-linking during the formation of the polymer, since cross-linked polymers are generally too rigid to be readily processed. However, it is sometimes desirable to cross-link the product after it has been formed, for example by heating, as in the case with curing rubber and other polymers. Cross-linking increases the dimensional stability of the polymer.

One very useful technique for cross-linking is to prepare the polymers to contain a small number of ethylenimino groups. Such molecules are readily crosslinked by heating at any time after formation. The cross-linking appears to take place by a free radical mechanism in which adjacent polymer chains are linked through tetramethylene groups. In polymers which are prepared for cross-linking, the number of ethylenimino groups per repeating unit is generally from 0.0001 to 0.2.

As stated above, the compounds of this invention are useful for a wide variety of purposes. They may be formed into fibers, films, or numerous types of molded products.

A special advantage of the products is that they can be formed into food colorants which are not adsorbed through the intestinal wall, and are fully and safely excreted. This is especially important with colorants which are suspected of metabolizing into toxic products when absorbed. These colorants may also be incorporated into color coded coatings for pills and other medicaments.

Products of this invention intended for use as food colorants will generally have alkoxy or aryloxy substituents so as to increase the resistance to hydrolytic decomposition. Normally, the selected product will be a Formula I type since many of the Formula II type products would be subject to displacement reactions with gastric acid.

Products selected for use as fibers will preferably have a glass transition temperature below 25"C, and a chain length greater than 1000 monomer residues.

Since at least some degree of microcrystallinity is desirable in fiber forming polymers, the organo groups will all be identical to enhance molecular orientation.

For use in films for optical filters and for photographic emulsions, the degree of microcrystallinity should be low to minimize opalescence. As with fibers, the chain length is generally above 1000 monomer units.

A reaction such as Reaction A in Equation A is normally conducted in a polar organic solvent under anhydrous conditions at a temperature of from -30"C to 175"C. It is preferred, but not essential, to conduct the reaction under an inert atmosphere, e.g. nitrogen.

Typically useful solvents include ethers containing up to eight carbon atoms, esters containing up to ten carbon atoms, and symetrical or non-symetrical ketones containing up to ten carbon atoms.

Reaction time is usually from 10 to 600 minutes.

The molar quantity of chromophoric compounds employed for reaction will be selected on the basis of the desired ratio of organo to chromophore groups.

Reaction B may be effected without isolation of the intermediate chromophoric group substituted polymer by adding the fluoro substituted salt or other selected compound to the reaction mixture. Preferably, addition takes place over a period of from 0.25 to 3 hours while maintaining the temperature at from -300C to 1500C.

At the end of the addition period, the reaction mixture is allowed to stand at a temperature of from 25"C to 1000C for from 3 to 10 hours to complete reaction.

Generally, the amount of trifluoro substituted compound or equivalent compound employed will be at least sufficient to replace the calculated number of chlorine atoms which remain on the polymer substrate based on the quantities of original polymer and chromophore reactants.

The final product may be recovered (and purified, if desired) in any convenient manner. Several procedures are illustrated in the examples.

Reactions C, D and E are all essentially similar. It is convenient to effect these reactions in the presence of a hydrogen chloride scavenger e.g. pyridine or triethylamine. The reactions take place under anhydrous conditions.

In the presently preferred procedure, reaction is carried out in a solvent which must, of course, be reaction inert. Any of a wide variety of solvents that will dissolve the polymeric starting material may be employed. These include, for example, aromatic hydrocarbon solvents e.g. benzene and toluene and cyclic ethers e.g. dioxane and tetrahydrofuran.

The time and temperature of the reaction will vary within very wide ranges, depending principally on the selected reactants. The temperature range may extend from -320C to 350C, or even higher, and the time from 2 to 48 hours.

A few simple observations will permit those skilled in the art readily to determine the optimum temperature and time of reaction for a particular set of reactants.

The various methods of isolation of the final product are illustrated in the examples. Normally, the procedure will vary with the solubility characteristics of the product. If it is soluble in the organic solvent in which it is prepared, it may be isolated by evaporation of the solvent or precipitation with a nonsolvent, after removing the insoluble salt formed from the scavenger by filtration. If both polymer and amine salt are insoluble in the organic reaction medium, but soluble in water, the amine salt can be removed by dialysis using water.

Acid addition salts e.g. those illustrated by Formula II are normally prepared in organic or aqueous solvents by mixing the selected reactants at a temperature of from -90"C to 1500C. The duration of the reaction is not critical, and will vary appreciably with the particular reactants, the temperature and the quantities employed. Some reactions will be essentially complete in as short a time as one minute. Others will give optimum results only after reaction period of four or five hours.

Typically useful organic solvents include aromatic and aliphatic hydrocarbons, ketones and ethers, suitably acetone, benzene or tetrahydrofuran.

The following non-limiting examples are given by way of illustration only.

EXAMPLE 1 Poly[( l -phenylazonaphthalene-2-oxy-trifluoroethoxy)phosphazene] The sodium salt of lphenylazo-2-hydroxynaphthalene is prepared with excess sodium hydride in tetrahydrofuran (THF) solution, initially under nitrogen atmosphere for 30 min. The color of the solution changes from red-orange to deep red as the salt forms.

A solution of sodium l-phenylazonaphthalene-2-oxide (0.38 g, 0.0014 mol) in THF (250 ml) is filtered through a glass frit in a Schlenk-type addition funnel by a positive nitrogen pressure into a reaction vessel which contains a stirred solution of poly(dichlorophosphazene) (15.7 g, 0.14 mol) in THF (1400 ml) under dry nitrogen atmosphere. The addition takes place over 30 min. After 1 hr. of reaction, an etheric (250 ml) solution of sodium trifluoroethoxide (39.8 g, 0.33 mol) is added slowly during 2 hr. The color of the reaction mixture changes from orange-red, through brown, and then to orange during the 36 hr. reaction at 25 . The polymer is recovered by removal of the solvent at reduced pressure and precipitation into heptane. It is purified by precipitation twice from THF into distilled water and 7 times from THF into heptane or benzene (Yield, 16.2 g, 51%).

The corresponding methoxy, ethoxy, butoxy and phenyloxy compounds are similarly prepared.

Analogous compounds of all of the above compounds are prepared by replacing the azo dye with celliton yellow, golden yellow and golden orange I.

EXAMPLE 2 Poly[( l -phenylazonaphthalene-2-oxy-methylamino)phosphazene] A solution of sodium-l-phenylazonaphthalene-2-oxide (0.24 g, 1x10-3 mol) in THF (200 ml) is pressure filtered under nitrogen into a stirred solution of poly(dichlorophosphazene) (11.2 g, 0.01 mol) in THF (700 ml). The total addition time is 35 min. After a further 90 min. of reaction time, the mixture is transferred to an addition funnel and added dropwise during 3 hr, to a stirred solution of methylamine (43 ml, 0.96 mol) in THF (500 ml) at 0 . Atmospheric moisture is rigorously excluded. After an additional 42 hr. reaction, solvent is removed at reduced pressure and the polymer isolated by precipitation into heptane. Purification is effected by dialysis in water for 48 hr., centrifugation for 30 min. at 10,000 r.p.m., and multiple precipitation from aqueous 95% ethanol into THF or heptane until no free dye is detected spectroscopically in the precipitation medium. Yield, 3.4 g, 30.4%. The polymer is orange in color. It forms hydroscopic, brittle films that were soluble in water, methanol, or ethanol, but only slightly soluble in isopropanol.

The corresponding ethylamino, propylamino and diethylamino compounds are similarly prepared.

A mixed organo group polymer is prepared utilizing an equimolar mixture of methyl and butyl amines.

Analogous compounds of all of the above compounds are prepared by replacing the dye with oil orange, para red and martins yellow.

EXAMPLE 3 Poly[(p-phenylazoanilino-methylamino)phosphazene] A solution of p-phenylazoaniline (0.34 g, 0.0017 mol) and triethylamine (9.8 ml) in benzene (50 ml) is allowed to react with poly(dichlorophosphazene) (II) (20 g, 0.17 mol) under a dry nitrogen atmosphere for 35 min. The mixture is then added dropwide to a solution of methylamine (91.8 ml, 2.06 mol) in THF (700 ml) at 0 under a nitrogen atmosphere. A color change from orange-brown to bright yellow occurs at this stage, and a fine precipitate forms. After a further 48 hr. of reaction, first at oa and later at 250, the product is isolated and purified by dialysis in water for 5 days. Subsequent precipitation 8 times from methanol into benzene ensures removal of all the non-covalently bound dye. Yield, 4.3 g, 23.4%. G.P.C. analysis in methanol or aqueous 95% methanol indicated an Mn value near 1.1 x 106. UV-visible spectroscopy of solutions of 0.0205 g of polymer in 10 ml of aqueous 95% ethanol indicated that (assuming an average chain length of 15,000 repeating units) approximately six dye molecules were attached to each polymer chain. The polymer forms yellow or green, brittle, hydroscopic films that are soluble in water, methanol, or ethanol, but only slightly soluble in isopropanol.

The corresponding ethylamino, propylamino, and butylamino compounds are similarly prepared.

The analogous compounds of all of the above are prepared by replacing the dye with celliton orange, celliton violet R, cellitazol ST, yellow AB, sudan violet and chrysaniline.

EXAMPLE 4 Poly[( 1 -Phenylazo-2-naphthylamino-methylamino)phosphazene] A solution of l-phenylazo-2-naphthylamine (0.5 g, 2x10-3 mol) in glyme (250 ml) is added slowly over 45 min. to a rapidly stirred solution of poly(dichlorophosphazene) (15.7 g, 0.15 mol) in THF (1500 ml) under dry nitrogen atmosphere. After 2 hr. of reaction, the stirred mixture is contacted at OOC with a large excess of methylamine added as a cooled liquid by means of a dry ice condenser. The reaction temperature is allowed to rise to 250C over 4 hrs., and the mixture is then dialyzed to remove hydrochloride salts. The resultant polymer is then isolated by freeze-drying.

The corresponding diethylamino, propylamino and butylamino compounds are similarly prepared except that the polymer is isolated as a film by solution casting, The analogous compounds of all of the above are prepared by replacing the chromophoric group with the chromophoric group derived from celliton orange, cellitazol ST, yellow AB, brown V, auramine, sudan violet or sudan green.

EXAMPLE 5 Poly[( 1 -phenylazo-4-p-oxophenylazonaphthalene-ethoxy)phosphazenel The sodium salt is prepared of l-phenylazo-4-(p- hydroxyphenylazo)naphthalene (0.25 g, 7.1x10-4 mol) with excess sodium hydride in a warm benzene-THF mixture. This mixture is then added to a solution of poly(dichlorophosphazene) (15.7 g, 0.14 mol) in a benzene-THF mixture (1500 ml), and reaction is allowed to proceed at 600C for 12 hr. To this solution is added an excess of sodium ethoxide, and the mixture is stirred at 250 for 24 hr. The polymer is recovered by precipitation from ethanol into water.

The corresponding compound in which one-half of the ethoxy groups are replaced with ethoxy groups are similarly prepared utilizing a 1:1 mixture of sodium methoxide and sodium ethoxide.

EXAMPLE 6 The sodium salt of p-nitrophenol (0.8 g, 5x 10-3 mol) is prepared by reaction of p-nitrophenol with aqueous sodium hydroxide solution, followed by rigorous drying. A suspension-solution of this material in THF (200 ml) is added to a stirred solution of poly(dichlorophosphazene) (11.2 g, 0.01 mol) in THF (700 ml). After the mixture has been stirred for 7 hr., an excess of butylamine is added and stirring is continued for 24 hr. The yellow polymer is recovered by precipitation into water.

The analogous methylamino and dimethylamino compounds are similarly prepared.

The analogous compound of all of the above are prepared by replacing the chromophoric group with the chromphoric group derived from Martius yellow.

EXAMPLE 7 Polypiperidinophosphazene with Chromophore Derived from 1,4-Diaminoanthraquinone A solution-suspension of 1,4-diaminoanthraquinone (0.24 g, 1x10-3 mol, Sudan Violet) in THF (300 ml) is added to a stirred solution of poly(dichlorophosphazene) (11.2 g, 0.01 mol) in benzene (600 ml). After I hr, of reaction at 500, the mixture is contacted with piperidine. The piperidine hydrochloride was filtered off, and the colored polymer was precipitated in ethanol and redissolved in benzene for casting as a film.

The analogous sudan green compound is similarly prepared from the sodium salt of the chromophore.

EXAMPLE 8 Polyphosphazene with Chromophore Derived from Chrysaniline Substituted with Trifluoroethylamino and Triethylamino Groups A solution of 3-amino-9-p-aminophenylacridine (chrysaniline) (0.27 g, lx 10-3 mol) in a 300 ml of 50:50 mixture of toluene and diglyme is added to a solution of poly(dichlorophosphazene) (15.7 g, 0.14 mol) in 2000 ml of benzene. After stirring for 1 hr. at 25 , the mixture is contacted with an excess of a 50:50 mixture of trifluoroethylamine and triethylamine, and stirred at 300 for 24 hr. The small molecule amine hydrochloride salts are filtered off, and the solution is evaporated to form yellow films.

EXAMPLE 9 Poly[bis(methylamino)phosphazene] Salt with Rhodamine B A solution of poly[bis(methylamino)phosphazene] (1 g) in water (100 ml) is mixed with a solution of 0.2 g of rhodamine B in aqueous alcohol and stirred at 35"C for two hours. The blue red polymer is solution cast as a film. The strong binding of the dye to the polymer is established by the inability of the dye to be removed by dialysis.

Other salts are similarly formed by replacing the rhodamine B with amido naphthol brown, gallocyanine, chrysamine, direct orange, fast red, metanil yellow, victoria violet, biebrich scarlet or orange R.

The corresponding ethylamino, propylamino, ethoxy and butoxy compounds are similarly prepared by replacement of the starting methylamino polymer with the appropriately substituted compound.

EXAMPLE 10 Poly[bis(phenylamino)phosphazine] Salt with Fast Red A solution of poly[bis(phenylamino)phosphazene] (1 g) in THF is mixed with a THF solution containing 0.1 g of fast red. The mixture is stirred at 600for three hr., cooled and isolated by precipitation by the addition of water.

WHAT WE CLAIM IS:- 1. A poly(organophosphazine) containing at least some units of formula:

or of formula

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (21)

**WARNING** start of CLMS field may overlap end of DESC **. drying. A suspension-solution of this material in THF (200 ml) is added to a stirred solution of poly(dichlorophosphazene) (11.2 g, 0.01 mol) in THF (700 ml). After the mixture has been stirred for 7 hr., an excess of butylamine is added and stirring is continued for 24 hr. The yellow polymer is recovered by precipitation into water. The analogous methylamino and dimethylamino compounds are similarly prepared. The analogous compound of all of the above are prepared by replacing the chromophoric group with the chromóphoric group derived from Martius yellow. EXAMPLE 7 Polypiperidinophosphazene with Chromophore Derived from 1,4-Diaminoanthraquinone A solution-suspension of 1,4-diaminoanthraquinone (0.24 g, 1x10-3 mol, Sudan Violet) in THF (300 ml) is added to a stirred solution of poly(dichlorophosphazene) (11.2 g, 0.01 mol) in benzene (600 ml). After I hr, of reaction at 500, the mixture is contacted with piperidine. The piperidine hydrochloride was filtered off, and the colored polymer was precipitated in ethanol and redissolved in benzene for casting as a film. The analogous sudan green compound is similarly prepared from the sodium salt of the chromophore. EXAMPLE 8 Polyphosphazene with Chromophore Derived from Chrysaniline Substituted with Trifluoroethylamino and Triethylamino Groups A solution of 3-amino-9-p-aminophenylacridine (chrysaniline) (0.27 g, lx 10-3 mol) in a 300 ml of 50:50 mixture of toluene and diglyme is added to a solution of poly(dichlorophosphazene) (15.7 g, 0.14 mol) in 2000 ml of benzene. After stirring for 1 hr. at 25 , the mixture is contacted with an excess of a 50:50 mixture of trifluoroethylamine and triethylamine, and stirred at 300 for 24 hr. The small molecule amine hydrochloride salts are filtered off, and the solution is evaporated to form yellow films. EXAMPLE 9 Poly[bis(methylamino)phosphazene] Salt with Rhodamine B A solution of poly[bis(methylamino)phosphazene] (1 g) in water (100 ml) is mixed with a solution of 0.2 g of rhodamine B in aqueous alcohol and stirred at 35"C for two hours. The blue red polymer is solution cast as a film. The strong binding of the dye to the polymer is established by the inability of the dye to be removed by dialysis. Other salts are similarly formed by replacing the rhodamine B with amido naphthol brown, gallocyanine, chrysamine, direct orange, fast red, metanil yellow, victoria violet, biebrich scarlet or orange R. The corresponding ethylamino, propylamino, ethoxy and butoxy compounds are similarly prepared by replacement of the starting methylamino polymer with the appropriately substituted compound. EXAMPLE 10 Poly[bis(phenylamino)phosphazine] Salt with Fast Red A solution of poly[bis(phenylamino)phosphazene] (1 g) in THF is mixed with a THF solution containing 0.1 g of fast red. The mixture is stirred at 600for three hr., cooled and isolated by precipitation by the addition of water. WHAT WE CLAIM IS:-

1. A poly(organophosphazine) containing at least some units of formula:

or of formula

wherein X is a chromophoric group, R is an organo substituent, the number of said units is from 250 to 20,000 and the ratio X:R is from 1:1 to 1:15,000.

2. A polymer according to claim 1 wherein R is alkoxy, aryloxy, alkylamino, dialkylamino, arylamino or diarylamino, where the alkyl groups have up to 5 carbon atoms and aryl is phenyl or substituted phenyl.

3. A polymer according to claim 1 wherein R is methoxy, ethoxy, propoxy, butoxy, isobutoxy, methylamino, ethylamino, propylamino, butylamino, phenylamino, trifluoroethoxy or piperidino.

4. A polymer according to any preceding claim wherein X is a chromophoric group derived from one of the azo, nitro, ketone amine, anthraquinone, acridine, triphenylmethane, oxazine, phthalocyanine, indigoid or sulfur dyes.

5. A polymer according to any preceding claim wherein X is a chromophoric group derived from one of the azo dyes Celliton yellow, Celliton orange, Golden yellow, Golden orange I, Celliton violet R, Oil orange, Para red, Cellitazol ST, Yellow AB, Brown V and Celliton fast yellow Chrysamine, Benzo fast yellow, Fast red, Methanil yellow, Victoria violet, Biebrich scarlet, and orange R.

6. A polymer according to any of claims I to 4 wherein X is Martius yellow, pnitrophenol or amido naphthol brown.

7. A polymer according to any of claims I to 4 wherein X is auramine.

8. A polymer according to any of claims 1 to 4 wherein X is Sudan violet or Sudan green.

9. A polymer according to any of claims 1 to 4 wherein X is Chrysaniline or proflavin.

10. A polymer according to any of claims 1 to 4 wherein X is Fuchsine.

Il. A polymer according to any of claims 1 to 4 wherein X is Amido naphthol brown or Gallocyanine.

12. Poly[( l -phenylazonaphthaline-2-oxy-trifluoroethoxy)phosphazene] .

13. Poly[( 1 -phenylazonaphthalene-2-oxy-methylamino)phosphazene] .

14. Poly[(p-phenylazoanilino-methylamino)phosphazenei.

15. Poly[( l -phenylazo-2-naphthylamino-methylamino)phosphazene] .

16. Poly[( l -phenylazo-4-p-oxophenylazonaphthaleneethoxy)phosphazene] .

17. A polymer according to claim 1 substantially as described herein with reference to any of the Examples.

18. A coloured film incorporating a polymer as claimed in any preceding claim.

19. A fibrous material coloured by means of a polymer as claimed in any of claims 1 to 17.

20. A food colourant composition comprising a polymer as claimed in any of claims 1 to 17.

21. A food stuff coloured by means of a food colourant composition according to claim 20.