GB2266093A - Polymers of cyclic ethers - Google Patents

Abstract

Hydroxy-terminated poly(alkylether) homopolymers and random copolymers are derived from either substituted oxiranes or from nitratoalkyl-substituted or azidoalkyl-substituted oxetanes and the copolymers from a wide range of oxiranes and higher cyclic ethers, particularly oxetanes. The polymers preferably contain from 20 to 150, most preferably 50 to 100, substituted oxyethylene repeat units in each polymeric chain, and have the formula: <IMAGE> wherein R<1> and R<2> are independently selected from hydrogen and methyl; R<3> and R<4> are H or 1 to 10 C alkyl, 1-2C chloroalkyl and bromoalkyl, or 1-5C nitratoalkyl, nitratoalkoxyalkyl, nitroalkyl, nitroalkoxyalkyl, azidoalkyl, azidoalkoxyalkyl, fluoronitroalkyl, and fluoronitroalkoxyalkyl, provided that at least one of R<3> and R<4> is not hydrogen; Z is an optionally-substituted alkylene group containing at least three bridging carbon atoms except that it is substituted when a is zero; R<5> is a residue of an organic hydroxy material which originally contained 1 to 6 hydroxyl groups; a is zero or 1 to 200; b is zero or 1 to 199 except that when a is zero, b is 5 to 200; (a + b) is at least 10; and c is 1 to 6. <IMAGE>

Description

POLYMERS OF CYCLIC ETHERS This invention relates to certain hydroxy-terminated poly(alkylene ether) homo- and random co-polymers.

Cationic polymerisation of cyclic ethers by quasi-living chain extension is a wellknown mechanism by which polymers can be'prepared. In such polymerisation reactions, a cationic oxonium ion forms with acidic catalyst at the end of the chain which reacts with incoming monomer molecules. The incoming molecules then acquire this cationic reactivity as they bond to the chain end to promote further chain growth (ie propagation). These quasiliving chain polymerisation reactions are frequently "seeded" by an initiator compound, present in small quantities in the reaction mixture which may form an initial part of the propagating polymer chain. Chain growth can be controlled by quenching the reaction at the appropriate time with an appropriate terminating agent eg water to give hydroxyl terminal groups.

In theory, cationic quasi-living chain polymerisation of cyclic ethers produces high purity polymers of narrow polydispersity, and since all the chains within the reaction mixture would be expected to grow at approximately the same rate. In practice, however close control over chain growth is difficult to achieve because the highly reactive chain ends to the growing polymer chains will usually undergo rapid reaction with any available unreacted monomer. Furthermore, the basicity of the monomer strongly affects the mode of the reactions involved during chain growth, since various nucleophiles other than the monomer, such as the linear ether group i the polymer chain and the counter anion at the growing end, are also present in the reaction system.Thus, chain growth competes with various side reactions, and as a result, polydispersivity is broadened and the production of unwanted impurities increased.

These problems apply in particular to the cationic polymerisation of substituted oxiranes to produce hydroxy-terminated polyether prepolymers suitable for use in elastomerforming cross-linking reactions with appropriate curing agents. Such polymerisations, conducted within chloroalkane solvents, have been described by Hammond et al (J Polymer Science 9 pp265-279, 1971) who used small amounts (typically less than 2 mol%) of diols as initiators and protonic acids (specifically BF3 etherate) as catalysts.

More recent attempts at producing poly(chloroalkylene) ethers by living chain polymerisation are disclosed in UK Patent Application GB 2021606A, which describes the reaction of chioroalkylene oxide monomers with an organic hydroxy-containing compound (typically a diol) in the presence of a catalyst system consisting of a fluorinated acid and a polyvalent organo-tin compound. Highly reactive oxonium ions which form at the chain ends during propagation readily react back into the polymer chain by attacking the oxo linking species to produce cyclic oligomers and short chain byproducts.These unwanted impurities can represent up to 50% contamination in the resultant prepolymer and can considerably broaden its polydispersivity, and as such seriously affect the cure of such prepolymers, the density of cross-links within the cured material, and hence its elastomeric properties.

Cyclic oligomer contamination can be reduced or even avoided in such polymerisation reactions, but only by deliberately choosing to produce polymers of low molecule weight.

This- is because it is usually found that the most common cyclic oligomer contaminants produced during the polymerisation of oxiranes are cyclic tetramers which occur in substantial amounts by the aforementioned back-reaction mechanism once the growing chain contains at least 5-6 alkylene oxide repeat units. By terminating chain growth before it reaches this size, the formation of these oligomers is avoided. However, this also effectively limits the maximum molecular weight of substantially oligomer-free polymer which can be produced from, for example, epichlorohydrin monomer and ethylene glycol precursor, to about 1000.

The applicant's co-pending application no 2249314A provides a process for polymerising at least one cyclic ether monomer which is capable of undergoing cationic ion ring-opening polymerisation selected from the group comprising oxetanes and nitrato- and nitro-substituted oxiranes, comprising reacting the monomer with a catalyst and an organic hydroxy-containing precursor compound, the catalyst being capable of generating oxonium ions by reacting with the monomer and the precursor compound having at least one hydroxy functional group for initiating polymerisation of the monomer, wherein the polymerisation comprises the steps of:: (a) mixing monomer together with stoichiometric excesses of both the catalyst and the precursor compound to promote formation of said oxonium ions and subsequent reaction between said ions and the hydroxy groups on molecules of the precursor compound to give a non-ionic product having at least one hydroxyl terminal group, the molar ratio of precursor compound to catalyst being at least 5:f where f is the hydroxy functionality of the precursor compound; and (b) bringing further of the monomer into contact with the reaction mixture at a sufficiently low rate to maintain the catalyst in stoichiometric excess over the monomer such that the non-ionic product of step (a) undergoes chain extension polymerisation with further of said oxonium ions, said chain extended polymer having at least one hydroxyl terminal group.

The organic hydroxyl compound ls preferably polyfunctional having from 2 to 6 hydroxyl groups.

That process is applicable to any cyclic ether monomer capable of undergoing cationic oxonium ion ring-opening polymerisation and yet by careful control of monomer and precursor concentration the process maintains a non-ionic hydroxyl terminal group, rather than a highly reactive terminal ionic species, on each growing polymer chain. The advantage of such a polymerisation is that without these ionic species the competing cyclic oligomer transfer process is substantially suppressed and so a virtually quantitative conversion of monomer to polymer then becomes possible. The process utilises a protonated monomercatalyst species (ie the oxonium ion) as the reactive cationic species throughout polymerisation, so that the rate of chain growth can be carefully controlled by controlling the admission of monomer to the reaction mixture.In this way, a close control over polydispersivity can also be achieved.

The aforementioned process may be used to prepare the hydroxy-terminated poly (alkylene ether) homo- and random co-polymers of the present invention. This invention provides a hydroxy-terminated poly(alkylether) homopolymer or random copolymer having the formula:

wherein Rl and R2 are independently selected from hydrogen and methyl;R3 and R4 are independently selected from hydrogen, alkyl containing from 1 to 10 carbon atoms, chloroalkyl and bromoalkyl containing 1 to 2 carbon atoms, and nitratoalkyl, nitratoalkoxyalkyl, nitroalkyl, nitroalkoxyalkyl, azidoalkyl, azidoalkoxyalkyl, flouronitroalkyl, and fluoronitroalkoxyalkyl containing 1 to 5 carbon atoms, provided that at least one of R3 and R4 is not hydrogen; Z is an optionally-substituted alkylene group containing at least three bridging carbon atoms except that it is substituted when a is zero; R5 is a residue of an organic hydroxy material which material originally contained from 1 to 6 hydroxyl groups; a is zero or an integer from 1 to 200; b is zero or an integer from 1 to 199 except that when a is zero, b is an integer from 5 to 200; (a + b) is at least 10; and c is an integer from 1 to 6.

Copolymers according to the present invention may be produced by the polymerisation of a mixture of monomers comprising two or more types of cyclic ether each containing the same number of ether ring carbon atoms but different substituent groups such as a mixture of two or more oxiranes. Alternatively a mixture of monomers comprising a mixture of different cyclic ethers containing different numbers of ring carbon atoms may be used, which when copolymerised form random copolymers with irregular distributions of ether linkages along the polymer chain, such as an oxirane mixed with an oxetane or THF. These latter copolymers possess several advantages, when cured to form elastomers, over their homopolymer analogues in that invariably glass transition temperature is lowered due to their more irregular structure to produce better elastomer properties. By varying the ratio of cyclic ethers in the monomer mixture it therefore becomes possible to tailor the properties of the polymer to particular applications.

Preferred alkyl-substituted oxiranes which may be used to prepare the polymers of the present invention include 1,2-epoxypropane, 2,3-epoxypentane, and 1,2-epoxyhexane.

Preferred chloroalkyl- and bromoalkyl-substituted oxiranes include epichiorohydrin, epibromohydrin, l-chloro-2-methyl-2,3-epoxypropane, and 1-chloro-2,3-dimethyl-2,3-epoxybutane, 1,1 -dichloro-2,3-epoxypropane, 1,1,1 -trichloro-2 , 3-epoxypropane, l-bromo-l,1- dichloro-2,3-epoxypropane, 1, l-dichloro-l-fluoro-2,3-epoxypropane, -difluoro- 1 -chioro- 2,3-epoxypropane, 1, 1-dichloro-2-methyl-2,3-epoxypropane, 1,1,1 ,-trichloro-3 ,4- epoxybutane, 1, 1-dichloro-3 ,4-epoxybutane, 1,1,1,2, 2-pentachloro-3 ,4-epoxybutane, 1,1,1 ,4,4-pentachloro-2,3-epoxybutine, 1,1,1,2,2-mixed pentahalo-3 ,4-epoxybutane, and 1,1,1 , 2 , 2-pentachloro-2-methyl-2 , 3 -epoxybutane 1,1 ,4,4-tetrachloro-2,3-epoxybutane, 1,1 ,2,2-tetrachioro-3 ,4-epoxybutane and 1,1,1 ,2-tetrachloro-3 ,4-epoxybutane.

Preferred nitratoalkyl-substituted oxiranes include glycidyl nitrate and 1,2-epoxy-4nitratobutane. Preferred fluoronitro-substituted oxiranes include fluorodinitroglycidyl ether.

Other oxiranes which may be used in the preparation of polymers according to the present invention include cyclohexane oxide and styrene oxide, though if present they preferably represent less than 50 mol% of the total oxirane content of the monomer.

Preferred oxetanes which may be used in the preparation of polymers according to the present invention to form highly energetic copolymers with oxiranes containing energetic nitro, azido, fluoronitro and (in particular) nitrato groups, are nitratoalkyl-substituted oxetanes such as 3,3 -bisnitratomethyloxetane, 3 -nitratomethyl-3 -methyloxetane, 3 nitratomethyl-3-ethyloxetane, and 3 -nitratomethyl-3-chloromethyloxetane, nitroalkoxyalkylsubstituted oxetanes such as 3 -(2, 2-dinitropropoxymethyl)-3 -methyl oxetane, fluoronitroalkoxyalkyl-substituted oxetanes such as 3 -(2-fluoro-2 ,2-dinitroethoxymethyl)-3 - methyl oxetanes, and azidoalkyl-substituted oxiranes such as 3,3 -bis(azidomethyl)-oxetane.

The substituent groups in these substituted oxetanes preferably contain up to 5 carbon atoms.

The hydroxyl-containing organic materials which provide the residue R5 in the polymers of the present invention for homopolymerising and copolymerising oxiranes include liquid and solid organic materials which have a hydroxyl functionality of at least one, preferably from 2 to 6, most preferably 2 or 3. These materials may be monomeric or polymeric and are preferably selected from monomeric and polymeric polyols (ie containing at least 2 hydroxyl groups per molecule), The hydroxy groups of the organic materials may be terminal or pendant groups.

Hydroxyl-containing materials containing both terminal and pendant hydroxyl groups may also be used. The molecular weight of the organic hydroxyl-containing material may be in the range of from 34 to about 2,500.

Preferably, the organic hydroxyl-containing material is an aliphatic material which contains at least one primary or secondary aliphatic hydroxyl group (ie the hydroxyl group is bonded directly to a non-aromatic carbon atom). Most preferably said organic material is an alkane polyol.

Monomeric alcohols and polyols which may be incorporated in the polymers include methanol, ethanol, isopropanol, 2-butanol, l-octanol, octadecanol, 3-methyl-2-butanol, 5propyl-3-hexanol, cyclohexanol, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, glycerol, tetramethylene glycol, 1,2,6-hexanetriol, 1,1,1 -trimethylolpropane, pentaerythritol, 2-hydroxy-2-ethylpropane- 1,2 diol, tris(hydroxymethyl)nitromethane, and sorbitol, and further include, especially when one of R3 and R4 is a chloroalkyl group, 2-chloroethanol, 3-chloropropanol, 2,3dichloropropanol, 3 ,4-dibromo- 1 ,2-butanediol, 2, 3-dibromo-1 ,4-butanediol, 1,2,5,6tetrabromohexane-3 ,4-diol.

Polymeric polyols which may be incorporated include polyoxyethylene and polyoxypropylene glycols and triols of molecular weights from about 200 to about 2000, hydroxy-terminated polyalkadienes, and polytetramethylene glycols of varying molecular weight.

Preferably in the polymers of the present invention, b is in the range from 1 to 180 and preferably also the ratio of a to b is at least 1:9. Preferred polymers are those in which the species -(O-Z)- is derived from tetrahhydrofuran or a nitratoalkyl-substituted oxetane and at least one of R3 and R4 comprises a nitratoalkyl group or a chloroalkyl group.

Preferred homopolymers (a=zero) are those in which the substituted oxyalkylene group -(O-Z)- is derived from either a nitratoalkyl-substituted oxetane or an azidoalkyhlsubstituted oxetane, other than 3 ,3-bis(azidomethyl)-oxetane. Preferably in such a homopolymer b is from 10 to 150.

The molecular weight of the poly(alkylether) will generally lie within the range 2500 to 20,000 and will preferably contain between 20 and 150, more preferably between 50 and 100, substituted oxyethylene repeat units in each polymeric chain. The hydroxy-containing organic material from which the residue R5 is derived, is preferably a diol or triol to ensure the polymer can be used as an elastomer pre-polymer and yet does not possess too great a functionality for such use and may be any of those listed above. The species -(0-2)- is preferably derived from a cyclic ether other than an oxirane, especially tetrahydrofuran or a oxetane.

The present invention will now be described by way of example only.

A The Polvmerisation of Glycidyl Nitrate (GLYN) Safetv Note: Owing to the explosion hazard associated with glycidyl nitrate monomer and polymer the polymerisation and copolymerisation reacting should be undertaken in an armoured fume cupboard.

Example 1 The Preparation of Difunctional Polvnlvcidvl Nitrate The polymerisation reactor which consisted of a 500ml jacketed vessel equipped with magnetic stirrer, nitrogen inlet/outlet, thermometer and serum cap was cooled from 120 C to ambient under nitrogen. It was then connected, to a cooling circulator and charged with a 25% w/v mixture of butane-1,4-diol in dichloromethane (1.5g in 5ml, 0.0168 mol). The reactor was then thermostatted under nitrogen to 20 - C and a catalytic amount of tetrafluoroboric acid etherate -(HBF4.EtzO)- (0.28g, 0.00168 mol) was added dropwise over a period of 3 minutes.Immediately afterwards a dried 25 % w/v GLYN in dichloromethane solution (100g GLYN in 400ml dichloromethane), prepared by the method af Example 1 of the Applicant's Pending UK Patent Application 8907852, corresponding to published PCT Patent Application WO90/01028, was pumped in at constant flow rate over a period of 42 hours. When addition was complete a further reaction period of 2 hours was allowed before the reacting was terminated by addition of a large excess of sodium hydrogen carbonate solution. The polymer was then isolated by washing the organic layer with distilled water, drying over calcium chloride, then removing the solvent on a rotary evaporator. The resultant tacky polymer was then dried at 50 C for 60 hours in a vacuum oven.Yield 99g (99%). The crude product was shown to possess no oligomer and about 1% small molecule impurities by ' H and l3C nmr along with dual detector gel permeation chromatography.

Overall conversion to high polymer thus exceeded 98% isolated. The molecular weight of the polymer was: Mn = 4900, Mw = 6900 giving a polydispersivity (Mw /Mn) of 1.39.

Example 2 The Preparation of Difunctional Polvlycidvl Nitrate (Variation) The procedure followed that outlined in Example 1 above except that HSbF6 was used in place of HBF4. Yield was 99% with approximately 1 % small molecule impurities present.

The molecular weight of the polymer was: Mn = 5150, Mw = 6900 giving a polydispersivity of 1.34.

Example 3 The Preparation of Difunctional Polvycidvl Nitrate (Variation) The procedure followed that outlined in Example 1 above except that BF3 etherate was used in place of HBF4. Addition of monomer was delayed 1 hour in order to allow the initiatory complex to form, whereupon it was added over a 48 hour period. Yield was 98% with approximately 1 % small molecule impurities present. The molecular weight of the polymer was: Mn = 4700, Mw = 7150 giving a polydispersivity of 1.52.

Example 4 The Preparation of Difunctional Polvlycidvl Nitrate (Variation) The procedure followed that outlined in Example 3 above except that a catalytic amount of BF3 etherate was corrected with an equimolar amount of ethanol over a 30 minute period then used in place of the HBF4 of Example 1. Addition of monomer was not delayed and the monomer was added over a 48 hour period. Yield was again 99 % with approximately 1 % small impurities present. The molecular weight of the polymer was: = 5100, Mw = 7300 giving a polydispersivity of 1.43.

Examples 5-8 The Preparation of Difunctional Polvalvcidvl Nitrate (Variations) These procedures followed the method of Example 1 above except that ethane-1,2diol, trimethylene glycol, tetraethylene glycol, and nominal 1000 molecular weight polyethylene glycol (PEG) were used in place of the butane-1,4-diol. In all cases yield exceeded 97% and small molecular contamination did not exceed 2%. The molecular weights were all within the range: Mn = 5400-4650, Mw = 8000-6500 giving polydispersivities in the range 1.4 to 1.7. The highest polydispersivity (Mw /Mn) value of 1.69 was obtained when 1000 molecular weight PEG was used as initiator. Other MNV/Mn values were in the range 1.4 to 1.60.

Examples 9-12 The Preparation of Trifunctional Polvalvcidvl Nitrate These procedures followed the methods of Examples 1-4 except that metriol replaced butane-1,2-diol in equimolar amounts and a slightly larger amount of catalytic HBF4 (0.42g, 0.00525 mol) was used. Addition was again over a 42-48 hour period. Isolated yield were 98% and this material was uncontaminated with oligomers and small molecular contaminants.

The molecular weights of the polymeric products were all within the approximate range: Mn = 5900-5100, Mw = 8800-7600 giving polydispersivities in the range 1.45-1.65.

Examples 13-14 The Preparation of Trifunctional Polyglycidyl Nitrate (Variations) these procedures followed the method of- Example 9 except that 2-hydroxyl-2 ethylprop ane- 1, 2-diol and tris(hydroxymethylynitromethane were used instead of metriol.

The molecular weight of the polymeric product of Example 13 was: Mn = 5600, Mw = 8700 giving a polydispersivity of 1.62. The molecular weight of the polymeric product of Example 14 was: Mn = 5000, Mw = 7200 giving a polydispersivity of 1.45.

B The Polvmerisation of Epichlorohvdrin Examples 15-22 The Preparation of Di- and Trifunctional Polvepichiorohydrins These procedures followed the methods of Examples 1-4 and 9-12, except that an equimolar amount of epichlorohydrin was used instead of glycidyl nitrate and a 30 hour addition period was used. The lowest isolated yield recorded was 98 % and no monomer or oligomer was observed in any sample. The molecular weights of the polymeric products were all within the range: Mn = 5200-4000, Mw = 7000-5800 giving polydispersivity in the range of 1.30 to 1.70.

Example 23 The Preparation of Difunctional Polveoichlorohvdrin (Variation) The procedure followed the method of Example 1 except that an equimolar amount of epichlorohydrin was used and the addition period (of epichlorohydrin to the diol solution) was only 6 hours. The isolated yield of polymer was 97%, of which 7% was found to be cyclic oligomer contamination. These impurities were removed by precipitation into an 80:20 methanol water mixture to give 99% pure polymer of nominally 2,000 molecular weight in 82% overall yield.

C The Polvmerisation of Propvlene Oxide Examples 2425 The Preparation of Di- and Trifunctional Polypropylene Oxides These procedures followed the methods of Examples 1 and 9 except that a 24 hour propylene oxide addition period was used. The molecular weight of the polymeric product of Example 24 was: Mn = 4200, Mw = 5300 giving a polydispersivity of 1.27. The molecular weight of the polymeric product of Example 25 was: Mn = 4400, Mw = 6100 giving a polydispersivity of 1.39.

D The Copolvmerisation of Glvcidvl Nitrate and 3-Nitratomethvl-3-methvloxetane (NIMMO) Example 26 The Preparation of Polv(GLYN-NIMMO) Random Copolymer (50:50) The procedure followed the same outline procedure as in Example 1 above except that the monomer feed consisted of a 50:50 mixture of GLYN and NIMMO in dichloromethane.

Reaction time was 48 hours at 25 C. The resultant copolymer was recovered in 94% yield and was found to be contaminated with oligomer 12% and unreacted monomer 2%. These impurities were easily removed by precipitation into a 80:20 methanol:water mixture to give pure copolymer in 76% overall yield. The molecular weight of the copolymer was: Mn = 4200, Mw = 9600 giving a polydispersivity of 2.28.

Examples 27-32 The Preparation of Poly(GLYN-NIMMO) Random Copolvmers (Variations) These procedures followed that outlined in Example 26 above except that monomer molar ratios of 80:20, 70:30, 60:40, 40:60, 30:70, and 20:80 (GLYN-NIMMO) were used.

Typically as the amount of NIMMO present in the reaction mixture rose so did the amount of oligomer contamination. Thus at 80:20 overall yield was 96% and 7% oligomer contamination was present, whereas at 20:80 overall yield was 92% and this contained 19% oligomer.

Example 33 The Preparation of Polv(Epichlorohvdrin-THF) Rndom Copolymer (Variation) This procedure followed that outlined in Example 26 except that the monomer feed consisted of a 50:50 mixture of neat epichlorohydrin and THF (tetrahydrofuran). The solution was added over 40 hours at 0 C to yield the copolymer in 87% yield. This was contaminated with 17% oligomer.

Example 34 The Preparation of Difunctional Polyoxetane The polymerisation reactor which consisted of a 500ml jacketed vessel, equipped with magnetic stirrer, nitrogen inlet/outlet and serum cup was connected to a circulating bath. It was then charged with a 25% w/v mixture of butane - 1,4-diol in dichloromethane (1.55g in 5mls, 0.017 mol). The reaction was thermostatted under nitrogen at 30 C and a catalytic amount of tetrafluoroboric acid etherate (HBF4 .OEt2) (0.29g 0.0017 mol) added.

Immediately afterwards a dried 20% w/v oxetane solution in dichloromethane (20g oxetane in m dichloromethane, 0.34 mol) was pumped in at constant flow for a period of 16 hours.

When addition was complete a further reaction period of 4 hours was allowed before the reaction was terminated by addition of a 2-fold excess of aqueous sodium hydrogen carbonate. The polymer was then isolated by washing with water, drying the dichloromethane solution with calcium chloride and removing the solvent on a rotary evaporator. The resultant amorphous polymer was then dried at 50 C for 72 hours in a vacuum oven. Yield 19g (95%). The crude product was shown to possess less than 2% oligomer impurity by use of dual detector gpc. The molecular weight of this polymer was Mn = 1200, Mw = 1450, MW/Mn = 1.20.

Example 35 The Preparation of Difunctional Polvoxetane (variation) As Example 34 except that 50g (0.34 mol) of 3-nitratomethyl-3-methyloxetane (NIMMO) was used in place of oxetane. Yield was 49g, (98%) with 4% oligomer present.

The molecular weight of this polymer was Mn = 3100, Mw = 3600, MW/Mn = 1.16.

Example 36 The Preparation of Difunctional Polv(NIMMO) As Example 34 except that a larger amount of oxetane was used in order to generate a higher molecular weight. Thus 60g oxetane in 240ml dichloromethane was added over a 48 hour period. Yield 5 8g (96%). The crude product was shown to possess less than 3% oligomer contamination. The molecular weight of this polymer was Mn = 3500, Mw = 4300, Mw /Mn = 1.23.

Example 37 The Preparation of Difunctional Poly(NIMMO) (Variation) As Example 36 except that 150g NIMMO in 600my dichloromethane was used. Yield = 141g (94%). The crude product possessed 5% oligomer contamination. The molecular weight of this polymer was Mn = 8900, Mw = 11100, MW/Mn = 1.25.

Claims (8)

Claims

1. Hydroxy-terminated poly(alkylether) homopolymer or random copolymer having the formula:

wherein R1 and R2 are independently selected from hydrogen and methyl; R3 and R4 are independently selected from hydrogen, alkyl containing from 1 to 10 carbon atoms, chloroalkyl and bromoalkyl containing 1 to 2 carbon atoms, and nitratoalkyl, nitratoalkoxyalkyl, nitroalkyl, nitroalkoxyalkyl, azidoalkyl, azidoalkoxyalkyl, flouronitroalkyl, and fluoronitroalkoxyalkyl containing 1 to 5 carbon atoms, provided that at least one of R3 and R4 is not hydrogen; Z is an optionally-substituted alkylene group containing at least three bridging carbon atoms except that it is substituted when a is zero; R5 is a residue of an organic hydroxy material which material originally contained from 1 to 6 hydroxyl groups; a is zero or an integer from 1 to 200; b is zero or an integer from 1 to 199 except that when a is zero, b is an integer from 5 to 200 (a + b) is at least 10; and c is an integer from 1 to 6.

2. Hydroxy-terminated poly ( alkylether) copolymer according to claim 1 characterised in that b is from 1 to 180.

3. Hydroxy-terminated poly ( alkylether) copolymer according to claim 1 or claim 2 characterised in that the ratio of a to b is at least 1:9.

4. Hydroxy-terminated poly(alkylether) according to any one of claims 1 to 3 characterised in that the species -(0--Z-)- is derived from tetrahydrofuran or a nitratoalkyl-substituted oxetane and at least one of R3 and R4 comprises a nitratoalkyl group or a chloroalkyl group.

5. Hydroxy-terminated poly(alkylether) according to any one of claims 1 to 4 characterised in that c is 2 or 3.

6. Hydroxy-terminated poly(alkylether) according to any one of claims 1 to 5 characterised in that at least one of R3 and R4 is selected from the group consisting of nitratoalkyl and azidoalkyl.

7. Hydroxy-terminated poly(alkylether) homopolymer according to claim 1 characterised in that the substituted oxyalkylene group -(0--Z)- is derived from either a nitratoalkyl-substituted oxetane or an azidoalkyl-substituted oxetane excluding 3,3-bis(azidomethyl)-oxetane.

8. Hydroxy-terminated poly(alkylether) homopolymer according to claim 7 characterised in that b is from 10 to 150.