GB2410498A

GB2410498A - Hyperbranched polyvinylalcohol

Info

Publication number: GB2410498A
Application number: GB0401740A
Authority: GB
Inventors: Stephen Rimmer; Stephen Collins
Original assignee: University of Sheffield
Current assignee: University of Sheffield
Priority date: 2004-01-28
Filing date: 2004-01-28
Publication date: 2005-08-03
Also published as: GB0401740D0

Abstract

A hyperbranched polymer, such as hyperbranched polyvinylalcohol, comprising repeating units derived from a] an unsaturated monomer, such as a vinyl monomer, such as vinyl acetate, vinyl propionate, vinyl butyrate, an N-vinyl monomer such as N-vinyl caprolactam, N-vinyl pyrrolidone, N-vinyl pyrrolidinone, that polymerises via a non-stabilised radical and b] a monomer comprising an ethylenically unsaturated carbonate moiety, such as an alpha-allyl carbonate, a beta-allyl carbonate, a vinyl carbonate and a secondary alkoxy moiety, such as an isopropoxy, isobutoxy moiety. Also disclosed is functionalisation of the hyperbranched polymer using a lipase enzyme and use of the hyperbranched polymer for the controlled release of a drug, a pesticide or a cosmetic.

Description

HYPERBRANCHED POLYMERS

This invention relates to hyperbranched polymers, and more particularly to hyperbranched polymers derived from vinyl monomers. s

Hyperbranched polymers (containing two or more generations of branching) are well known. The formation of high molecular weight hyperbranched polymers from AB2 monomers containing one group of type A and two of type B was first described in US Patent 4857630. Numerous other hyperbranched polymers have been reported since that time, for example, by Hawker et al, J. Am. Chem. Soc. 113, 4252-4261, (1991); Turner et al, Macromolecules, 27, 1611 (1994); and in US Patents Nos. 5196502; 5225522; and....

5214122. All of these hyperbranched polymers were obtained by polycondensation..

processes involving AB2 monomers. In general, the known hyperbranched polymers have irregularly branched structures with high degrees of branching between 0.2 and 0.8. A. . 15......

The degree of branching DB of an AB2 hyperbranched polymer has been defined.. . by the equation DB=(1-f) in which f is the mole fraction of AB2 monomer units in which only one of the two B groups has reacted with an A group.

Highly branched polymers have also been prepared in multistep processes involving a graft on graft technique that leads to a dramatic increase in molecular weight as a result of successive stepwise grafting steps. Examples of such polymers are disclosed in Tomalia et al, Macromolecules, 24, 1435 (1991) and US Patent 4694064.

The preparation of hyperbranched polymers by self-condensing vinyl polymerization of 3-(1-chloroethyl)-ethenylbenzene was first disclosed in Frechet J. M. Science, 269, 1080- 1083 (1995). s

In US Patent No. 5663260 there is disclosed a process for the preparation of a hyperbranched polymer comprising initiating polymerization of and thereafter coplymerising a solution comprising an AB monomer and a C monomer, each of which is individually polymerisable, to produce growing chains in which A and B are reactive groups that react independently of each other, in which A contains a group polymerisable in living fashion, C is a monomer that contains a group polymerisable in living fashion, B is a precursor of an active B* species capable of effecting the living polymerization of A and C as a result of being activated, wherein B is activated and B* adds to any A or C polymerisable group and wherein each of A, B. and C are compatible with each other AB and C monomer combinations are exemplified by vinyl ethers such as 1- (2-vinyloxyethyloxy)-1'-[2-(1-acetoethoxy)-ethyloxy]-4,4'-isopropylidene diphenol and isobutylvinylether, and styrenes such as 4-(1 -chloroethyl) styrene and 4-methylstyrene.

US Patent No. 5767211 discloses the synthesis of multi-functional hyperbranched polymers by free radical polymerization of di- or tri- vinyl monomers in the presence of a chain transfer agent and a non- peroxide free radical initiator. Monomers disclosed are dimethacrylates, diacrylates, bismethacrylamides, bisacrylamides, di(isopropenyl)benzene, divinylbenzene, trimethacrylates and triacrylates, wherein said dimethacrylates and diacrylates contain a diol spacer and said bismethacrylamides and his acrylamides contain a diamine spacer and said trimethacrylates and triacrylates contain a core structure.

Yamada et al, Polymer (2000) vol. 41, 5625 describe the polymerization of methyl methacrylate and styrene with a branching agent having methacryloyl and alpha (benzylthiomethyl)acryloyl groups.

EPl062248 describes a method of preparing a branched polymer comprising the steps of mixing together a monofunctional vinylic monomer with from 0. 3 to 100% w/w of a polyfunctional vinylic monomer and from 0.0001 - 50% w/w of a chain transfer - ..

agent and thereafter reacting said mixture to form a polymer. Monofunctional monomers disclosed are methacrylates and acrylates, styrene and derivatives thereof, vinyl acetate, maleic anhydride, itaconic acid, N-alkyl (aryl) maleimides and N-vinyl pyrrolidone Polyfunctional monomers disclosed are bi-functional (meth)acrylates, tri- functional (meth)acrylates, tetra-functional (meth)acrylates, pen/a-functional (meth) acrylates, hexa functional (meth)acrylates, oligomers or polymers having more than one polymerisable vinylic group, and mixtures thereof.

Despite the broad disclosure of EP 1062248, it has been found that only hyperbranched polymers derived from monomers that polymerise via stabilised radicals, for example, acrylates, methacrylates and styrenics, can be produced as described.

Commercially useful hyperbranched polymers derived from monomers that polymerise via non-stabilised radicals, for example, vinyl alkyl esters and N-vinyl monomers, cannot be produced in this way, 1) because only a few monomers can polymerise with such monomers, and 2) because the usual chain transfer agents have chain transfer constants, with monomers that polymerise via non-stabilised radicals, that are far too high to allow chain propagation to occur concurrently with transfer.

According to the present invention, there are provided novel hyperbranched polymers derived from monomers that polymerise via non- stabilised radicals and methods for their production.

In a first aspect, the present invention provides a hyperbranched polymer comprising repeating units derived from a) an unsaturated monomer that polymerises via a non-stabilised radical and b) a monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety. if.

In a second aspect, the present invention provides a method for the production of a hyperbranched polymer which comprises copolymerising a) an unsaturated monomer that polymerises via a non-stabilised radical and b) a monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety.

In a further aspect, the present invention provides a hyperbranched polymer of formula I: Ion IMP o \R6 Wry,: R8 A (1) wherein: ë e Rat = H. C-6 alkyl, or C-6 alkenyl '. :' . e . O R3

11 / I' A = - O - C - R2, or - N \ .... R4

R2= Cl -6 alkyl R3 = Cl-6 alkyl R4= Cat 6alkyl, or CORs R5 = C -6 alkyl R6 = C' 6alkenyl R7 = C' 6 alkyl R8 = C, 6 alkyl R9 = H. C1-6 alkyl, or C- 6 alkenyl And n, p and q are each independently integers.

In the present specification, an unsaturated monomer that polymerises via a non stabilised radical is defined as one that, following addition of a radical to its unsaturated moiety, produces a new radical that is not stabilized by -electron delocalization. In a preferred embodiment of the invention, the unsaturated monomer that polymerises via a non-stabilised radical is a vinyl monomer.

A preferred class of unsaturated monomers that polymerise via a nonstabilised. ,, radical according to the present invention includes unsaturated carboxylic acid esters, and ...,' more particularly unsaturated alkyl esters, especially vinyl alkonates of the general ace ä formula CH2=CH-O-CO-R' , wherein: : I Ret= -CH3, (CH2)rCH3'or -(CH2) s(CH)CH3 . and r, s, and t are each independently integers, .. :.

for example, vinyl C-2 alkyl esters, such as vinyl acetate, vinyl propionate and vinyl butyrate.

Another preferred class of monomers that polymerise via a non-stabilised radical includes N-vinyl monomers, more particularly N-vinyl monomers of the formula: Rll CH2=CH-N Rl2 wherein Rl = C l l2 alkyl R'2 = Cat '2 alkyl, or CoR'3, and R'3 = C-2 alkyl, or wherein R" and Rt2 together with the N atom form a 5- or 6- membered ring optionally having one or more hetero substituent atoms or groups, for example, N-vinylamides such as, for example, N-vinyl caprolactam, N-vinyl pyrrolidone and N-vinyl pyrrolidinone.

The monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety is preferably one that can generate radicals by abstraction of hydrogen radicals and thereby act as a branching monomer. The monomer preferably comprises, as the ethylenically unsaturated carbonate moiety, a Co-ed ethylenically unsaturated moiety, for example, an oc-allyl carbonate-, a p-allyl carbonate, or a vinyl carbonate. The secondary alkoxy moiety is preferably a C'-2 secondary alkoxy moiety, for example, an isopropoxy, or isobutoxy moiety. The ethylenically unsaturated carbonate moiety and the secondary alkoxy moiety can be linked together by a covalent bond, or the monomer can comprise a linking group, more particularly an alkylene group, for example, a Cl-12 alkylene group, or an alkyloxy group, for example, an ethyloxy group.

The monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety can have the general formula: o R10-OJo_ Where Rl = Cl-2 alkenyl and Rll = Cl 12 branched alkyl or Cl-2 branched alkyloxy Preferably R' is a vinyl group or an allyl group. Preferably Rid is an isopropyl group or a 2-isopropoxy group.

Examples of preferred monomers comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety include: . 00 00.

Carbonic acid Isopropyl vinyl ester, Carbonic acid isopropenyl ester isopropyl ester . /\oJ(ol - J - 'I Carbonic acid allyl ester isopropyl ester and Carbonic acid allyl ester 2-isopropoxy-ethyl ester In the method of the invention, the monomers are preferably polymerized in the presence of a free radical initiator, which can comprise, for example, azobisisobutyronitrile, potassium persulphate, sodium persulphate, or hydrogen peroxide.

The free radical initiator can be activated to produce free radicals by any of the agents known in the art of radical polymerization, for example, heat, light, ionizing radiation or redox processes. The free radical initiator is preferably present in an amount of from 0.1 to 5.0 % w/w of the total monomer content.

The polymerization of the monomer mixture may be performed using any suitable free-radical polymerization method, for example, solution, suspension, emulsion, and bulk polymerization methods may all be used. For many applications of the hyperbranched polymers of the invention, the material is required in solid form, in which case suspension or bulk polymerization may be preferred.

In an important further aspect of the invention, it has been found that the products of the polymerization can be influenced by the presence of certain solvents in the reaction mechanism. Thus, for example, it has been found that the presence of certain secondary alkyl alcohols, for example, isopropanol and 2-isopropoxy ethanol, reduces the cross linking tendency of the polymer and can result in branched but not cross-linked polymers Cross-linking can occur if the propagating polymer branches terminate by combination en.

Where the production of a cross-linked network or gel is desired, the reaction can be.. . carried out, for example, in the presence of an ester, for example, n-butyl acetate. In another method of minimizing "elation, the reaction can be carried out at higher temperatures, for example, at temperatures greater than 100 C, preferably greater than 120 C, more preferably from 125 C to 175 C, in order to increase the rate of chain transfer.

For the avoidance of doubt, it is to be understood that the present invention includes both branched (but not cross-linked) polymers, and also polymers comprising branched, cross-linked networks or gels.

In the method of the invention, both chain propagation and chain transfer reactions take place, as illustrated schematically in Figure I below, using a carbonic acid vinyl ester isopropoxy alkyl ester as an example of a branching monomer: Figure 1 Propagation via radical addition to the vinyl group O..

0 Aim. P a:

R / O-R / I. 0 / 0: P..

pi- R \ Transfer \ =, ...

\ 0 Polymerizabonof R 0( + RH monomer, M p - R, 0

O-R 10.Mn

wherein R is an alkylene group, R* is a free radical initiator and M is a monomer that polymerises via a non-stabilised radical.

l he monomers can be mixed in any suitable ratio, and, for example, the monomers a) and b) may be mixed in a ratio of from 80:20 to 1:99 by weight, preferably from 60:40 to 20:80 by weight.

The hyperbranched polymers of the invention may also comprise additional repeating units derived from other monomers, and in particular from monomers that polymerise via a stabilised radical, for example, methacrylates, acrylates, styrenics, acrylamides and methacrylamides. Where one or more additional monomers are used, these are preferably present in total amount of from 1 to 50 parts by weight, based on 100 parts by weight of monomers a) and b) combined. ..

The hyperbranched polymers of the invention may find a variety of uses, .

depending upon their chemical structure and physical properties. Thus, certain polymers. . in accordance with the invention are biodegradable and may find applications in the...

human body and in the environment. They may have unusual theological properties and may accordingly be used, when appropriately functionalised, as slow release agents and vehicles for carrying drugs, for example, in gene therapy, and in cosmetics and pesticides.

T hey may also find uses as dispersion aids in food, paint, cosmetic, adhesives formulations or in heterogeneous polymerizations.

The invention also includes, in a further aspect, functionalised hyperbranched polymers produced from polymers of the invention by appropriate chemical modification of pendant groups. Such polymers can be produced, for example, by enzymatic modification of the polymers of the first aspect of the invention. Preferred polymers according to this aspect of the invention are hyperbranched polyvinylalcohol polymers.

In a first preferred embodiment of this aspect of the invention, polymers of the first aspect of the invention comprising pendant alkyl ester moieties can be subjected to enzymatic hydrolysis using lipases, for example, lipases from pseudomonas Jluorescens or rhizopus arrihuz. These lipases selectively catalyse the hydrolysis of the pendant alkyl ester moieties whilst leaving the carbonate moieties derived from the branching monomer (b) unaffected. An example of the reaction is illustrated in Figure 2 below: . em. ..:

Figure 2., - age C Llpase tarIMP 2 Rz: O = 0 _ C/ R2 i

OH

where R2, R6, n, p, and q are as previously defined.

In a second embodiment of this aspect of the invention, hyperbranched polymers of the first aspect of the invention can be converted into block copolymers by reactions that link other polymer chains to the chain termini via selective modification using enzymatic or non-enzymatic reaction of the ultimate repeat unit. For example, hyperbranched polymers comprising pendant alkyl ester groups can be converted by selective enzymatic modification to hyperbranched polyvinyl alkonate-block caprolactone polymers, using, for example, a lipase derived from porcine pancreas. This enzyme polymerizes s-caprolactone by transesterification of hydroxyl and alkyl ester moieties but does not catalyse the hydrolysis of the carbonate moieties derived from the branching monomer (b). The enzymatic reaction can be used to polymerise caprolactone from the hyperbranched polymer backbone, as illustrated in Figure 3 below: - me.: Figure 3. .

A

co-, ,co- L'pase 0)=0..e A, Hi

O H

where R2, R6, n, p, q are as previously defined.

As used herein, unless otherwise stated, alkyl and alkoxy, whether used alone or as part of a substituent moiety, include straight and branched chains. For example, an alkyl moiety includes methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t butyl, n-pentyl, 3-(2-methyl) butyl, 2-pentyl. 2-methylbutyl, neopentyl, n-hexyl, 2-hexyl, and 2methylpentyl. Alkoxy moieties include oxygen ethers formed from the previously described straight or branched chain alkyl groups.

The term aryl as used herein alone or in combination with other terms indicates an aromatic hydrocarbon group such as phenyl or naphthyl. The term aralkyl denotes an alkyl group substituted with an aryl group.

The invention is illustrated by the following non-limitative Examples: . .

EXAMPLES. .

Example 1 .

lOml(0.1090mol) vinyl acetate were polymerized in the presence of lOml(0. 1306mol) . . isopropanol, 0.5ml(0.0033mol) carbonic acid isopropyl vinyl ester and 54mg...

azobisisobutyronitrile (AIBN). The components were added to a glass ampoule and degassed for four freeze-pump-thaw cycles, before being flame sealed. The polymerisation was conducted at 60 C for 4 hours. After the allotted time the ampoule was removed and quenched in ice, before rotary evaporation to remove excess monomers and solvents. The sample was then dissolved in THF and precipitated into 40-60 Petroleum ether(GPR grade), twice, before drying in vacuo.

Example 2

1 Oml(0.1090mol) vinyl acetate were polymerized, in the presence of 1 Oml(0.1306mol) isopropanol solvent, l.Oml(0.0066mol) carbonic acid isopropyl vinyl ester and 56mg AIBN. The reaction and recovery of the sample were performed as for example 1.

Example 3

lOml(O.lO9Omol) vinyl acetate were polymerised in the presence of lOml(0. 1306mol) isopropanol, 2.0ml(0.0131mol) carbonic acid isopropyl vinyl ester and 56mg AIBN. The reaction and recovery of the sample were performed as for example 1.

Example 4

lOml(0.1090mol) vinyl acetate were polymerised in the presence of 15ml(0. 1959mol) isopropanol, 0.5ml(0.0033mol) carbonic acid isopropyl vinyl ester and 52mg AIBN. The reaction and recovery of the sample were performed as for example I. ....

Example 5.

lOml(0.1090mol) vinyl acetate were polymerized, in the presence of 20ml(0. 2612mol) isopropanol, 0.5ml(0.0033mol) carbonic acid isopropyl vinyl ester and 54mg AIBN. The.. , reaction and recovery of the sample were performed as for example 1. .. ,

Example 6 -.

lOml(0.1090mol) vinyl acetate were polymerized in the presence of lOml(0. 0867mol) 2 isopropoxy ethanol, 0.5ml(0.0027mol) carbonic acid allyl ester 2-isopropoxy-ethyl ester and 62mg AIBN. The reaction and recovery of the sample were performed as for

example 1.

Example 7

lOml(0.1090mol) vinyl acetate were polymerized in the presence of lOml(0. 0867mol) 2 isopropoxy ethanol, l.Oml(0.0055mol) carbonic acid allyl ester 2-isopropoxy-ethyl ester and 58mg AIBN. The reaction and recovery of the sample were performed as for

example 1.

Example 8

lOml(0.1090mol) vinyl acetate were polymerised in the presence of lOml(0. 0867mol) 2 isopropoxy ethanol, 2.0ml(0.0109mol) carbonic acid allyl ester 2-isopropoxy-ethyl ester and 57.5mg AIBN. The reaction and recovery of the sample were performed as for

example 1.

Example 9

lOml(O.lO90mol) vinyl acetate were polymerised in the presence of 15ml(0. 1301mol) 2 isopropoxy ethanol, 0.5ml(0.0027mol) carbonic acid allyl ester 2-isopropoxy-ethyl ester and 63mg AIBN. The reaction and recovery of the sample were performed as for example 1. ..

Example 10.' . .

lOml(O.lO90mol) vinyl acetate were polymerised in the presence of 20ml(0. 1734mol) 2 isopropoxy ethanol, 0.5ml(0.0027mol) carbonic acid allyl ester 2-isopropoxy-ethyl ester 2. e and 65mg AIBN. The reaction and recovery of the sample were performed as for example. . * 1. 2'

Example 11

lOml(0.936mol) N-vinyl pyrrolidinone were polymerised in the presence of lOml(0.0759mol) n-butyl acetate, 0.5ml(0.0033mol) carbonic acid isopropyl vinyl ester and 60mg AIBN. These compounds were added to a glass ampoule, which was degassed for four freeze-pump-thaw cycles, before being flame sealed. The polymerization was conducted at 60 C for 2 tic: hours. After this reaction time the sample had formed a cross linked gel.

Example 12

l Oml(0.936mol) N-vinyl pyrrolidinone were polymerized in the presence of lOml(0.0759mol) n-butyl acetate, l.Oml(0.0066mol) carbonic acid isopropyl vinyl ester and 60mg AIBN. The reaction proceeded as in example l l, and resulted in a cross linked gel.

Example 13

l Oml(0.936mol) N-vinyl pyrrolidinone were polymerised, in the presence of lOml(0.0759mol) n-butyl acetate, 1.5ml(0.0098mol) carbonic acid isopropyl vinyl ester and 60mg AIBN. The reaction proceeded as in example 11 and resulted in a cross linked gel.

Example 14

1 Oml(0.936mol) N-vinyl pyrrolidinone were polymerised in the presence of lOml(0.0759mol) n-butyl acetate, 2.0ml(0.0131mol) carbonic acid isopropyl vinyl ester.

and 60mg AIBN. The reaction proceeded as in example 11 and resulted in a cross linked gel.. , .

Example 15 20.

lOml(0.936mol) N-vinyl pyrrolidinone were polymerised in the presence of I. lOml(0.0759mol) n-butyl acetate, 0.5ml(0.0027mol) carbonic acid allyl ester 2 isopropoxy-ethyl ester and 60mg AIBN. The reaction proceeded as in example 11 and resulted in a cross linked gel.

Example 16

l Oml(0.936mol) N-vinyl pyrrolidinone were polymerised, in the presence of lOml(0.0759mol) n-butyl acetate, l.Oml(0.0055mol) carbonic acid allyl ester 2 isopropoxy-ethyl ester and 60mg AIBN. The reaction proceeded as in example 1] and resulted in a cross linked gel.

Example 17

l Oml(0.936mol) N-vinyl pyrrolidinone were polymerised in the presence of lOml(0.0759mol) n-butyl acetate, 1.5ml(0.0082mol) carbonic acid allyl ester 2- isopropoxy-ethyl ester and 60mg AIBN. The reaction proceeded as in example l l and resulted in a cross linked gel.

Example 18

1 Oml(0.936mol) N-vinyl pyrrolidinone were polymerised in the presence of 1 Oml(0.0759mol) n-butyl acetate, 1.25ml(0.0068mol) carbonic acid allyl ester 2 isopropoxy-ethyl ester and 60mg AIBN. The reaction proceeded as in example 11 and. . resulted in a cross linked gel. ..:

Example 19

lOml(0.936mol) N-vinyl pyrrolidinone were polymerised in the presence of .

30ml(0.2278mol) n-butyl acetate, 2ml(0.0109mol) carbonic acid allyl ester 2-isopropoxy- .. ë ..

ethyl ester and 65mg AIBN. The reaction was performed in a stirred high pressure autoclave at 150 C for 1 hour. After reaction the liquid present was decanted off, and the branched but not cross linked polymer was dissolved in DCM, before precipitation into anhydrous diethyl ether. This was performed twice before drying in vacuo.

Example 20

lOml(O. lO90mol) vinyl acetate were polymerised in the presence of 30ml(0. 2278mol) n- butyl acetate, 2ml(0.0109mol) carbonic acid allyl ester 2-isopropoxy- ethyl ester and 60mg AIBN. The reaction was performed in a stirred high pressure autoclave at 150 C for 1 hour. After reaction the products were subjected to rotary evaporation to remove excess monomers and solvents. The sample, a branched but not cross linked polymer, was then dissolved in THE and precipitated into 40-60 Petroleum ether (GPR grade).

This was performed twice, before drying in vacuo.

GPC results for the products of Examples 1 - 10 and 20 are given in Table 1.

Table 1

Normal GPC Triple Detector GPC Example No. Mn/gmol Mw/gmoli Mn/gmol, Mw/gmol' 3610 46377 15854 77986 12437 46564 10203 102252....

13053 47100 11101 85480 8903 24721 30053 322953..

7030 17655 5919 25796 I. 6 13307 38585 27164 47138....

7 13931 44218 25631 59378... ..

8 21016 71517 98247 142434 9319 23717 12389 21912 8428 20234 15444 23105 7130 17099 12310 21956 The reader's attention is directed to all papers and documents that are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, . - equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of .

equivalent or similar features. :. :-

The invention is not restricted to the details of any foregoing embodiments. The :e invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A hyperbranched polymer comprising repeating units derived from a) an unsaturated monomer that polymerises via a non-stabilised radical and b) a monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety.

2. A polymer according to claim 1, wherein the unsaturated monomer that polymerises via a non-stabilised radical is a vinyl monomer.

3. A polymer according to claim 1 or 2, wherein the monomer that polymerises via a non-stabilised radical is an unsaturated carboxylic acid ester. .

4. A polymer according to any one of the preceding claims, wherein the monomer I . that polymerises via a non-stabilised radical is an unsaturated alkyl ester. .

5. A polymer according to any one of the preceding claims, wherein the monomer :.

that polymerises via a non-stabilised radical is a vinyl alkonate of the general - formula ClI2=CH-O-CO-Rt , wherein: R = -CH3' (CH2)rCH3, or -(CH2)s(CH) rCH3 and r, s, and t are each independently integers.

6. A polymer according to any one of the preceding claims, wherein the monomer that polymerises via a non-stabilised radical is a vinyl Co-ed alkyl ester.

7. A polymer according to any one of the preceding claims, wherein the monomer that polymerises via a non-stabilised radical is vinyl acetate, vinyl propionate, or vinyl butyrate.

8. A polymer according to any one of the preceding claims, wherein the monomer that polymerises via a non-stabilised radical is an N-vinyl monomer.

9. A polymer according to claim 8, wherein the N-vinyl monomer is an Nvinyl amide.

10. A polymer according to claim 8 or 9, wherein the N-vinyl monomer has the formula:

R

I A

CH2=CH-N, .2 R12. e. 15.:.

wherein ë Rll = Cl l2 alkyl Rl2 = Cl l2 alkyl, or CoRI3, and Rl3=Cl l2alkyl, or wherein Rl and Rl2 together with the N atom form a 5- or 6membered ring optionally having one or more hetero substituent atoms or groups.

1 1. A polymer according to any one of claims 8 to 10, wherein the Nvinyl monomer is N-vinyl caprolactam, N-vinyl pyrrolidone, or N-vinyl pyrrolidinone. l

12. A polymer according to any one of the preceding claims, wherein the monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety comprises, as the ethylenically unsaturated carbonate moiety, a C'-2 ethylenically unsaturated moiety.

13. A polymer according to claim 10, wherein the ethylenically unsaturated carbonate moiety is a vinyl carbonate or allyl carbonate moiety.

14. A polymer according to claim 10 or 1 1, wherein the ethylenically unsaturated carbonate moiety is an a-allyl carbonate-, a p-allyl carbonate, or a vinyl.. . carbonate. . ::. .

15. A polymer according to any one of the preceding claims, wherein the monomer.... -.

comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy. ..

moiety comprises, as the secondary alkoxy moiety a C'-2 secondary alkoxy moiety.

16. A polymer according to claim 15, wherein the secondary alkoxy moiety is an isopropoxy, or isobutoxy moiety.

17. A polymer according to any one of the preceding claims, wherein the ethylenically unsaturated carbonate moiety and the secondary alkoxy moiety of monomer b) are linked together by a covalent bond.

18. A polymer according to any one of claims 1 to 16, wherein the ethylenically unsaturated carbonate moiety and the secondary alkoxy moiety of monomer b) are linked together by a linking group.

19. A polymer according to claim 18, wherein the linking group is an alkyloxy group. ë

20. A hyperbranched polymer of formula I: .. . R' . MOP O. \ ë R6:. I. R8 A (I)

wherein: Rat = I-I, Cl 6 alkyl, or Cl 6 alkenyl O R3 A = - O - C - R2, or - N \ R2 = C 1-6 alkyl R3 = Cl 6 alkyl R4 = C'.6 alkyl, or CORs Rs = Cal 6 alkyl R6 = Cat 6 alkenyl ...

R7 = C -6 alkyl Ret = C-6 alkyl R9 = H. C -6 alkyl, or C -6 alkenyl.

And n, p and q are each independently integers.

21. A hyperbranched polymer according to any of the preceding claims, comprising a em. :e

cross-linked network or gel.

22. A hyperbranched polymer according to any one of the preceding claims, which comprises additional repeating units derived from other monomers.

23. A hyperbranched polymer according to claim 22, wherein the additional repeating units are derived from a monomer or monomers that polymerise(s) via a stabilised radical.

24. A hyperbranched polymer according to claim 23, wherein the monomer(s) that polymerise(s) via a stabilised radical is a methacrylate, acrylate, styrenic, acrylamide or methacylamide monomer.

25. A hyperbranched polymer according to any one of the preceding claims, substantially as described in the Examples.

26. A hyperbranched polymer substantially as hereinbefore described.

27. A method for the production of a hyperbranched polymer which comprises copolymerising a) an unsaturated monomer that polymerises via a non-stabilised radical and b) a monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety. ..

28. A method according to claim 27, wherein the unsaturated monomer that.

polymerises via a non-stabilised radical is a vinyl monomer. A. . ..

29. A method according to claim 27 or 28, wherein the unsaturated monomer that.

polymerises via a non-stabilised radical is an unsaturated carboxylic acid ester.

30. A method according to any one of claims 27 or 29, wherein the unsaturated monomer that polymerises via a non-stabilised radical is an unsaturated alkyl ester.

A method according to any one of claims 27 to 30, wherein the monomer that polymerises via a non-stabilised radical is a vinyl alkonate of the general formula CH2=CH-O-CO-R' , wherein: Rl = -CH3, -(CH2)rCH3, or -(CH2) s(CH)tCH3 and r, s, and t are each independently integers.

32. A method according to any one of claims 27 to 31, wherein the monomer that polymerises via a non-stabilised radical is a vinyl C'-2 alkyl ester.

33. A method according to any one of claims 27 to 32, wherein the monomer that polymerises via a non-stabilised radical is vinyl acetate, vinyl propionate, or vinyl butyrate. ..:

34. A method according to any one of claims 27 to 33, wherein the monomer that polymerises via a non-stabilised radical is an N-vinyl monomer. .

35. A method according to claim 34, wherein the N-vinyl monomer is an Nvinyl amide.

36. A method according to claim 34 to 35, wherein the N-vinyl monomer has the formula: CH2=CH-N \

R

wherein Rll = Cl l2 alkyl Rig = Cat '2 alkyl, or CoR'3, and R3 = Cat '2 alkyl, or wherein Ri, and R2 together with the N atom form a 5- or 6membered ring optionally having one or more hetero substituent atoms or groups.

37. A method according to claim 36, wherein the N-vinyl monomer is Nvinyl....

caprolactam, N-vinyl pyrrolidone, or N-vinyl pyrrolidinone. . .

38. A method according to any one of claims 27 to 37, wherein the monomer A. . comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy....

moiety comprises, as the ethylenically unsaturated carbonate moiety, a C'2.. ...

ethylenically unsaturated moiety.

39. A method according to claim 38, wherein the ethylenically unsaturated carbonate moiety is a vinyl carbonate or allyl carbonate moiety.

40. A method according to claim 38 or 39, wherein the ethylenically unsaturated carbonate moiety is an a -allyl carbonate, a,B-allyl carbonate, or a vinyl carbonate. l

41. A method according to any one of claims 27 to 40, wherein the monomer comprising an ethylenically unsaturated carbonate moiety and a secondary alkoxy moiety comprises, as the secondary alkoxy moiety, a Co-ed secondary alkoxy moiety.

42. A method according to claim 41, wherein the secondary alkoxy moiety is an isopropoxy moiety.

43. A method according to any one of claims 27 to 42, wherein the ethylenically.

unsaturated carbonate moiety and the secondary alkoxy moiety of monomer b) are. . linked together by a covalent bond.

44. A method according to any one of claims 27 to 43, wherein the ethylenically unsaturated carbonate moiety and the secondary alkoxy moiety of monomer b) are. . . linked together by a linking group.

45. A method according to claim 44, wherein the linking group is an alkyloxy group.

46. A method according to any one of claims 27 to 45, wherein the monomers are polymerised in the presence of a free radical initiator. '

47. A method according to claim 46, wherein the free radical initiator is present in an amount of from 0.1 to 5.0% w/w of the total monomer content.

48. A method according to any one of claims 27 to 47, wherein the monomers a) and b) are mixed in a ratio of from 80:20 to 1:99 by weight.

49. A method according to any one of claims 27 to 48, wherein the monomers are polymerized in the presence of an additional monomer or monomers.

50. A method according to claim 49, wherein the additional monomer is one that....

polymerises via a stabilised radical. ..

51. A method according to claim 50, wherein the additional monomer is a . . . methacrylate, acry l ate, styreni c, acry l amide or methacrylamide monomer. . 15.. ...

52. A method according to any one of claims 49 to 51, where the additional monomer(s) is/are present in a total amount of from 1 to 50 parts by weight, based on l DO parts by weight of monomers a) and b) combined.

53. A method according to any one of claims 27 to 52, which is carried out in the presence of a compound that reduces the amount of termination of the propagating polymer branches by combination.

54. A method according to claim 53, in which the compound is a secondary alkyl alcohol.

55. A method according to claim 54, in which the secondary alkyl alcohol is isopropanol or 2-isopropoxy ethanol.

56. A method according to any of claims 27 to 55, wherein the polymerization is carried out at a temperature sufficient to increase the rate of chain transfer.

57. A method according to claim 56, in which the temperature is from 125 C to C. . .

58. A method according to any one of claims 27 to 57, substantially as described in.. 2.

the Examples. .

15.. :.

59. A method for the manufacture of a hyperbranched polymer substantially as hereinbefore described.

60. A hyperbranched polymer produced by a method according to any of claims 27 to 59.

61. A hyperbranched polymer according to any of claims 1 to 26 that is biodegradable. l

62. A hyperbranched polymer according to any one of claims I to 26, which has been functionalised by chemical modification of pendant groups.

S

63. A hyperbranched polymer according to claim 62, which has been produced by enzymatic modification.

64. A hyperbranched polymer according to claim 63, which is a hyperbranched polyvinylalcohol polymer.

'..'..

65. A hyperbranched polymer according to claim 63 or 64, which has been produced.' . . by subjecting pendant alkyl ester moieties to enzymatic hydrolysis using a lipase.

66. A hyperbranched polymer according to claim 65, wherein the lipase is derived A. I 5 from pseudomonas fluorescens or rhizopus arrihuz. .,

67. A method for the manufacture of a hyperbranched block copolymer, which comprises reacting a hyperbranched polymer of any one of claims 1 to 26 to link other polymer chains to the chain termini via selective modification using enzymatic or non-enzymatic reaction of the ultimate repeat unit.

68. A method according to claim 67, wherein a hyperbranched polymer comprising pendant alkyl ester groups is converted by selective enzymatic modification to a hyperbranched polyvinyl alkonate-block caprolactone polymer, using a lipase.

69. A hyperbranched block copolymer produced by a method according to claim 67 or68.

70. Use of a hyperbranched polymer according to any one of claims 1 to 27, 60 to 66 and 69, for the modification of the theological properties of a fluid.

Use of a hyperbranched polymer according to any one of claims 1 to 27, 60 to 66. .- *,.

and 69, as a vehicle for the controlled release of a drug. . 72. Use of a hyperbranched polymer according to any one of claims I to 27, 60 to 66, , and 69, as a vehicle for the controlled release of a pesticide. . 73. Use of a hyperbranched polymer according to any one of claims 1 to 27, 60 to 66 and 69, as a vehicle for the controlled release of a cosmetic.