Patent Application
20090306297
A subject matter of the present invention is a process for the synthesis of a controlled-architecture copolymer comprising at least one block A obtained by the polymerization of ITP type of a mixture of monomers having ethylenic unsaturation (A0) not comprising monomers having vinylphosphonate functional groups and at least one block B obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (B0) comprising at least one monomer B1 carrying at least one vinylphosphonate functional group.
Another subject matter of the present invention is a process for the synthesis of a controlled-architecture copolymer of telomer type comprising at least one chain B obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (B0) comprising at least one monomer B1 carrying at least one vinylphosphonate functional group by polymerization of ITP type, and also the telomer capable of being obtained and its uses.
According to the present invention, controlled-architecture copolymers denote block copolymers, such as diblocks and triblocks, grafted copolymers, star copolymers, microgels or branched block copolymers comprising a microgel core with a variable and controlled crosslinking density (such as described in the application M. Destarac, B. Bavouzet and D. Taton, WO 2004/014535, Rhodia Chimie), and also telomers, that is to say polymers having controlled end functionality.
The term “monomer having a vinylphosphonate functional group” is understood to mean, within the meaning of the present invention, a monomer which comprises at least one vinylphosphonic acid functional group or an alkyl ester analog.
Mention may in particular be made, among monomers having a vinylphosphonate functional group, of the compounds of following formula (I):
in which:
The blocks or chains according to the invention can be homopolymers, random copolymers, alternating copolymers or copolymers having a composition gradient.
One of the technological approaches of choice which makes it possible to synthesize controlled-architecture copolymers is “living” or controlled radical polymerization.
Controlled-architecture copolymers are of use in various industries, in particular as dispersing, emulsifying, texturizing or surface-modifying agents.
Furthermore, (co)polymers carrying phosphonic acid functional groups are well developed industrially for their specific functions in varied fields, such as flame retardants, scale-inhibiting agents, corrosion inhibitors, adhesion promoters or pigment dispersants.
Thus, it is apparent that the synthesis of copolymers having complex architectures carrying phosphonate functional groups PO3R1R2 and in particular phosphonic acid functional groups PO3H2 represents a very great industrial challenge.
This is also a technical challenge quite capable of being accepted, for two main reasons:
This is the reason why, to date, the synthesis of homopolymers or copolymers comprising monomers comprising phosphonate functional groups has been carried out by a conventional radical route, that is to say by an uncontrolled mechanism.
The phosphonic acid functional groups PO3H2 are often generated by the hydrolysis of the corresponding esters, which can be provided by an appropriate monomer [Boutevin B. et al., Polym. Bull., 1993, 30, 243] or transfer agent [Boutevin B. et al., Macromol. Chem. Phys., 2002, 203, 1049] during the polymerization.
Very few studies relate to the direct incorporation of PO3H2 functional groups in polymers. This is, for example, the case in polymerizing vinylphosphonic acid, hereinafter denoted by VPA, by radical initiation [Herwig W., Duersch W. and Engelhardt F., U.S. Pat. No. 4,696,987] or by random copolymerization, for example with methacrylic acid [Riegel U., Gohla W., Grosse J. and Engelhardt F., U.S. Pat. No. 4,749,758]. The document GB 2 293 605 describes the polymerization of VPA and its random copolymerization with acrylic acid. Likewise, R. Padda et al. [Phosphorus, Sulfur and Silicon and the Related Elements, 2002, 177 (6-7), 1697] describe the random copolymerization of a diphosphonic monomer: vinylidenediphosphonic acid. With regard to the telomers, that is to say polymers having controlled chain endings, functionalized by PO3H2, Rhodia has developed a technology which makes it possible to synthesize polymers (for example, polyacrylic acid (PAA)) having a diphosphonic acid di(PO3H2) end unit [Davis et al., WO 2004/078662].
It is apparent that the polymers having phosphonate or phosphonic acid functional groups most commonly described are homopolymers, random copolymers, and even telomers, functionalized by a phosphonic acid at their end, these polymers being obtained by a conventional radical route, that is to say by an uncontrolled mechanism.
Mention may be made, among the main “living” or controlled radical polymerization techniques, of atom transfer radical polymerization (ATRP), radical polymerization controlled by stable radicals of nitroxyl type (NMP), reversible addition-fragmentation transfer (RAFT) polymerization and polymerization by degenerative transfer of iodine (ITP).
However, for ATRP, the phosphonic acid units and the ester analogs of the vinyl monomers and/or of the polymers formed have a tendency to strongly interact with the ATRP catalysts (Cu, Ru, Fe, Ni), which compromises the control of this polymerization.
For the NMP polymerization, the low level of stabilization of the radicals resulting from the vinylphosphonic acid monomers or from their ester analogs renders the polymerization of these monomers difficult to make compatible with this technique.
In the case where the polymerization is of RAFT type, in particular when the RAFT transfer agent is a xanthate, a process then referred to as the MADIX process (Macromolecular Design via the Interchange Xanthates), VPA has been randomly copolymerized with acrylic acid. Hydrophilic double copolymers P(acrylamide)-b-P(AA-stat-VPA) have been synthesized as described in the document M. Destarac and D. Taton, “Direct Access to Phosphonic Acid-Containing Block Copolymers via MADIX”, 40th International Symposium on Macromolecules, MACRO 2004, Paris. Amphiphilic copolymers P(BuA)-b-P(AA-stat-VPA) have been synthesized as described in the documents WO 2003/076529 and WO 2003/076531.
However, it is important to note that, in all the cases of MADIX polymerization described above, the level of incorporation of VPA in a block did not exceed 25 mol %.
In the academic literature, radical polymerization controlled by iodine transfer (ITP) or also by degenerative transfer (DT) has been described by M. Tatemoto in “Development of iodine Transfer Polymerization and its applications to telechelically reactive polymers”, Kobunshi Robunshu, vol. 49, No. 10, pp. 765-783 (1992). In this process, an end iodine atom (at the chain end) can be reversibly transferred during the polymerization from a chain end to a growing radical of another chain. The transfer agents commonly employed are alkyl or perfluoroalkyl iodides.
For the case of styrene and acrylates, mention may be made of the studies of Gaynor et al. in Macromolécules, 28, 8051-8056 (1995). Other examples of polymerization of styrene monomers by ITP are available in the references Macromolécules, 33(9), 3485 (2000), Macromolécules, 32(22), 7354 (1999) and Macromolécules, 31(9), 2809 (1998). The synthesis by ITP of block copolymers based on styrene and on acrylates has been described in the references Macromolécules, 28, 2093 (1995) and Macromol. Rapid Commun. 2000, 21(13), 921.
The ITP of vinyl acetate has been studied by Iovu et al. in Macromolécules, 2003, 36(25), 9346-9354.
Lacroix-Desmazes et al. in ACS Symposium Series, 854, 570-585 (2003), have studied the ITP polymerization of vinylidene chloride and have synthesized the corresponding block copolymers. These same authors have recently described, in Macromolécules, 2005, 38(15), 6299-6309, the radical polymerization of acrylates using molecular iodine I2, thereby naming this process reverse ITP or RITP.
The documents EP 0 489 370 and U.S. Pat. No. 5,439,980 from Daikin Industries describe the synthesis of block copolymers by reversible iodine transfer.
The documents EP 272 698 and EP 0 501 532 from Daikin industries describe the polymerization by ITP of fluoromonomers in order to access fluorinated block copolymers.
The documents EP 0 617 057, EP 0 974 604 and U.S. Pat. No. 5,455,319 from Geon Company relate to the ITP polymerization of halogenated monomers, in particular vinyl chloride.
The document EP 0 947 527 from B.F. Goodrich Company describes aqueous emulsion ITP polymerization in order to access in particular ABC triblock copolymers.
The document WO 03/097704 from Solvay describes the iodine transfer polymerization of compositions formed of halogenated monomers for some cases in the presence of molecular iodine I2 as transfer agent.
The document WO 2004/009648 from Akzo Nobel describes the synthesis of controlled-architecture copolymers by iodine transfer polymerization for which one of the blocks is rich in methacrylate monomers.
In the document WO 2004/009644 from Akzo Nobel, molecular iodine I2 is employed to control the polymerization of a methacrylic composition comprising at least one crosslinkable functional group.
Thus, none of the abovementioned documents relating to polymerization controlled by iodine transfer (ITP) describes the use of a monomer having a vinylphosphonate acid functional group.
The need existed to succeed in synthesizing block polymers, one of the blocks of which has a high composition of monomer having a vinylphosphonate functional group.
Specifically, the vinylphosphonate monomer is a relatively unreactive monomer which is generally much more expensive than the comonomers which accompany it in the reaction mixture. The fact of being capable of localizing it at will in a precise part of the polymer should make it possible to use less of it in achieving the desired property and thus to reduce the cost.
Furthermore, the fact of having several consecutive vinylphosphonate units in a polymer should make it possible to introduce advantageous properties, in particular when the polymers thus obtained are used as scale-inhibiting agents.
One of the aims of the present invention is to find a means of synthesizing controlled-architecture copolymers comprising at least one block based on monomers carrying vinylphosphonate functional groups with a high composition of vinylphosphonate functional groups.
This aim and others have been achieved by the Applicant Company by using a specific radical polymerization process of iodine atom transfer type (ITP).
Specifically, it is by virtue of the control of the reaction conditions, in terms of concentration of the reaction medium, and the conditions of temperature and of concentration of initiator and the nature and the concentration of the iodine-comprising transfer agent, that the Applicant Company has been able to obtain controlled-architecture polymers comprising blocks rich in vinylphosphonate monomer.
The subject matter of the present invention is thus a process for the synthesis of a controlled-architecture copolymer comprising at least one block A obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (A0) not comprising monomers having vinylphosphonate functional groups and at least one block B obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (B0) comprising at least one monomer B1 carrying at least one vinylphosphonate functional group comprising the following stages:
Another subject matter of the present invention is a process for the synthesis of a controlled-architecture copolymer of telomer type comprising at least one chain B obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (Bo) comprising at least one monomer B1 carrying at least one vinylphosphonate functional group comprising the following stage:
the following are brought into contact:
Another subject matter of the present invention is a controlled-architecture copolymer of telomer type capable of being obtained by the process of synthesis of the invention.
Finally, a subject matter of the present invention is the use of the controlled-architecture copolymer of telomer type capable of being obtained by the process of synthesis of the invention as surface-modifying agent, as dispersant or as emulsifier.
The controlled-architecture copolymer can be a block (di- or triblock) copolymer, a grafted copolymer, a star copolymer or a microgel, comprising at least one block A and at least one block B, and also a telomer comprising a chain B.
The block A according to the invention is obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (A0) not comprising monomers having vinylphosphonate functional groups. The block B is obtained by the polymerization of a mixture of monomers having ethylenic unsaturation (B0) comprising at least one monomer B1 carrying a vinylphosphonate functional group.
The blocks according to the invention can be homopolymers, random copolymers, alternating copolymers or copolymers having a composition gradient.
According to the invention, the ratio by weight of the blocks A and B varies between 1/99 and 99/1.
The block A is obtained by the polymerization of a mixture of monomers (A0) having ethylenic unsaturation not comprising monomers carrying a vinylphosphonate functional group. The group (A0) comprises hydrophilic monomers (h) or hydrophobic monomers (H) chosen from the following monomers:
Mention may be made, among hydrophilic monomers (h), of:
Preferably, the hydrophilic monomer units (h) are chosen from acrylic acid (AA), acrylamide (Am), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrenesulfonate (SS), N-vinylpyrrolidone, vinylsulfonic acid (VSA), or their mixtures, and the vinyl alcohol units resulting from the hydrolysis of polyvinyl acetate, or their mixtures.
More preferably still, acrylic acid (AA) or vinyl alcohol units are used.
Mention may be made, among monomers having a hydrophobic (H) nature, of;
Preferably, the hydrophobic monomer units (H) of the controlled-architecture copolymers of the invention are esters of acrylic acid with linear or branched C1-C8, in particular C1-C4, alcohols, such as, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate (BuA) or 2-ethylhexyl acrylate (2EHA), fluorinated acrylates, or else styrene derivatives, such as styrene, or vinyl acetate (VAc), or vinyl chloride, or vinylidene chloride, or vinylidene fluoride.
According to a preferred form of the invention, the block A is polyacrylic acid or polyvinyl alcohol.
The polyacrylic acid can be obtained either by polymerization of acrylic acid monomer or by polymerization of a monomer of alkyl acrylate type, such as, for example, methyl acrylate or butyl acrylate, followed by hydrolysis.
The polyvinyl alcohol can be obtained by polymerization of vinyl acetate, followed by hydrolysis.
As regards the block B or the chain B, it is obtained by the polymerization of a mixture of monomers (B0) comprising at least one monomer B1 carrying at least one vinylphosphonate functional group and optionally a monomer B2 not carrying a vinylphosphonate functional group chosen from the group A0 defined above.
Preferably, the block B or the chain B is obtained by the polymerization of a mixture of monomers (B0) comprising,
More preferably still, the block B or the chain B is obtained by the polymerization of a mixture of monomers (B0) comprising,
The monomer comprising at least one vinylphosphonate functional group B1 can be a compound of formula (I):
in which:
The term “halogen atom” is understood to mean chlorine, fluorine, bromine or iodine. Preferably, chlorine is used.
Mention may in particular be made, among the monomers B1 of use in the present invention, of vinylphosphonic acid, the dimethyl ester of vinylphosphonic acid, the bis(2-chloroethyl) ester of vinylphosphonic acid, vinylidenediphosphonic acid, the tetraisopropyl ester of vinylidenediphosphonic acid or α-styrenephosphonic acid, or their mixtures.
The monomers B1 having a vinyl mono- or diphosphonic acid functional group can be used in the free acid form or in the form of their salts. They can be partially or completely neutralized, optionally by an amine, for example dicyclohexylamine.
The monomer B1 which is preferred according to the invention is vinylphosphonic acid.
The monomer B2 of use in the present invention can be chosen from the monomers A0 defined above.
Preferably, the monomer B2 is chosen from acrylic acid, acrylamide, vinylsulfonic acid, vinyl acetate, butyl acrylate or their mixtures.
More preferably still, the monomer B2 is acrylic acid.
In general, the controlled-architecture copolymers exhibit a weight-average weight of between 1000 and 100 000, generally between 4000 and 50 000. They also exhibit a polydispersity index of less than 2.5, preferably of between 1.3 and 2.5 and more preferably between 1.3 and 2.0.
The ratio by weight between blocks A and B is such that B/(A+B) is preferably between 0.01 and 0.5 and more preferably still between 0.02 and 0.2.
When the block B is obtained by the polymerization of a mixture of monomers (B0) comprising from 50 to 100 mol % of at least one monomer B1 carrying at least one vinylphosphonate functional group, then the following conditions preferably exist:
The molecular weights of the block B are generally less than 10 000, preferably less than 5000 and more preferably still less than 2000.
The concentration of initiator and the method of introduction of the initiator are defined so as to obtain a good compromise between a high conversion of monomer B0 and a level of uncontrolled chains which is as low as possible.
Thus, the initiator is introduced batchwise at the beginning of the reaction, or portionwise, or continuously or semicontinuously, the monomer B, being placed, preferably as vessel heel, such that the cumulative or total concentration of the initiator is between 0.5 and 20 mol %, with respect to the mixture of monomers B0.
The level of solid made of monomer B0 is high in comparison with the usual conditions under which controlled radical polymerization processes are carried out.
Finally, the molecular weights of the block B have also been defined so as to effectively control the polymerization.
The iodine-comprising transfer agents of use by virtue of the invention all have at least one group which stabilizes the radical centered on the carbon adjacent to the iodine atoms. This group activates the reactants with regard to the transfer of iodine and for this reason renders the transfer agents effective. The iodine-comprising transfer agents can be classified into three categories:
The iodine-comprising transfer agent of use for the implementation of the processes of the invention can be chosen from reactive monoiodine compounds without a functional group of following formula (II):
R—I (II)
in which
R represents:
Examples of groups which stabilize the radicals R′ are C6H4 CH3, C6H5, (C═O)OCH3, F, Cl and CN.
Mention may be made, as examples, among compounds R—I, of 1-chloro-1-iodoethane, 1-fluoro-1-iodoethane, 1-phenyl-1-iodoethane, monoiodoperfluoroethane, monoiodoperfluoropropane, 2-iodoperfluorobutane, 1-iodoperfluorobutane, 1-iodoperfluoro(4-methylbutane), 1-iodoperfluorohexane, 1-iodoperfluoro-n-nonane, monoiodoperfluorocyclohexane, monoiodotrifluorocyclobutane, monoiododifluoromethane, monoiodomonofluoromethane, 2-iodo-1-hydroperfluoroethane, 3-iodo-1-hydroperfluoropropane, monoiodomonochlorodifluoromethane, monoiododichloromonofluoroethane, 2-iodo-1,2-dichloro-1 μl, 2-trifluoroethane, 4-iodo-1,2-dichloroperfluorobutane, 6-iodo-1,2-dichloroperfluorohexane, 4-iodo-1,2,4-trichloroperfluorobutane, 1-iodo-2,2-dihydroperfluoropropane, 1-iodo-2-hydroperfluoropropane, monoiodotrifluoroethane, 3-iodoperfluoroprop-1-ene, 4-iodoperfluoropentene, 1,4-iodo-5-chloropent-1-ene, 2-iodoperfluoro(1-cyclobutenyl)ethane, 1-iodoperfluorodecane, 2-iodo-1,1,1-trifluoroethane, 1-iodo-1-hydroperfluoro(2-methylethane), 2-iodo-2,2-dichloro-1 μl, 1-trifluoroethane, 2-iodoperfluoroethyl perfluorovinyl ether, 2-iodoperfluoroethyl perfluoroisopropyl ether, 3-iodo-2-chloroperfluorobutyl perfluoromethyl ether, iodopentafluorocyclohexane, iodoperfluorohexane, iodoacetonitrile, methyl 2-iodopropionate, ethyl 2-iodopropionate or benzyl iodide.
The preferred agents R—I are 1-iodoperfluorohexane (C6F13I), iodoacetonitrile (CNCH2I), methyl 2-iodopropionate (CH3CH(CO2CH3)—I), 1-phenyl-1-iodoethane (CH3 CH(C6H5)—I) and benzyl iodide (C6H5CH2—I).
The iodine-comprising transfer agent of use in the implementation of the process of the invention can also be chosen from monoiodine compounds carrying a functional group of following formula (III):
Z2-R′—I (III)
in which
R′ represents:
Examples of groups which stabilize the radicals Z2-R′ are C6H4CH3, C6H5, (C═O)OCH3, F, Cl and CN.
Z2 is selected from the following groups: OR1, N(R1)2, SR1, COOR1, COOM, olefin of the CR1═C(R1)2 type, epoxy, SO3M, P(O)(OR1)2, P(R1)2, isocyanate and CR1═O, where R1 is a hydrogen atom or a group having from 1 to 20 carbon atoms, R1 being identical or different for any Z2 having more than one R1 group, and where M is an alkali metal salt, such as a sodium or potassium salt.
The preferred transfer agents Z2-R′—I are 3-iodo-4-chloroperfluorobutyric acid, allyl iodide or also 1-iodo-1-phenylethanol (IIIa) or iodoacetic acid (IIIb) described below:
The diiodine-comprising transfer agents without a functional group are of following general formula (IV):
I—R′—I (IV)
in which:
R′ represents
Examples of groups which stabilize the radicals R′ are C6H4CH3, C6H5, (C═O)OCH3, F, Cl and CN.
Mention may be made, among the compounds I—R′—I, as examples, of 1,3-diiodoperfluoro-n-propane, 1,4-diiodoperfluoro-n-butane, 1,3-diiodo-2-chloroperfluoro-n-propane, 1,5-diiodo-2,4-dichloroperfluoro-n-pentane, 1,7-diiodoperfluoro-n-octane, 1,12-diiodoperfluorodecane, 1,16-diiodoperfluorohexadecane, 1,2-di(iododifluoromethyl)perfluorocyclobutane, 1,4-di(iododifluoromethyl)tetrafluorocyclohexane, 1,4-di(iodomethyl)benzene (IVa), ethylene glycol di(iodomethyl) ester (IVb) and dimethyl 2,5-diiodoadipate (IVc).
The preferred reactants I—R′—I are 1,4-di(iodomethyl)benzene (IVa), ethylene glycol di(iodomethyl) ester (IVb) and dimethyl 2,5-diiodoadipate (IVc).
The iodine-comprising reactant selected for the polymerization depends on the type of monomer polymerized and on the controlled architecture desired. A good balance between the rate of transfer and the rate of reinitiation must be found.
The three types of iodine-comprising transfer agents of formulae (II), (III) and (IV) can be used for the synthesis of controlled-architecture copolymers in several stages and for the synthesis of telomers in one stage.
It is preferable to use iodine-comprising transfer agents of formula R—I (II) or of formula I—R′—I (IV) for the synthesis of controlled-architecture copolymers in several stages.
It is preferable to use iodine-comprising transfer agents of formula R—I (II) or Z2-R′—I (III) for the synthesis of telomers.
The polymerization can be carried out in particular in bulk, in solvent or else in dispersed medium.
When the polymerization is carried out in solvent, said solvent is acetonitrile, ethyl acetate or an alcohol chosen from ethanol, isopropanol, or their mixtures with water, optionally.
The polymerization carried out in solvent in acetonitrile or an alcohol, such as ethanol, constitutes a preferred embodiment of the invention.
Water, an alcohol or an aqueous/alcoholic medium are more particularly recommended in the context of the use of hydrophilic monomers of the type of acrylic acid (AA), acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and styrenesulfonate (SS) and/or in the context of the use of hydrophobic monomers, such as n-butyl acrylate or 2-ethylhexyl acrylate.
Another subject matter of the invention is the use of the telomers according to the invention as surface-modifying agent (in particular as hydrophilizing, hydrophobizing or oleophobizing agent), for example for metal surfaces, as adhesion promoter, as corrosion inhibitor, as flame retardant, as dispersant or as emulsifier. It is mentioned that a copolymer where the block A comprises fluorine atoms and/or that a polymer obtained using an iodine-comprising transfer agent comprising fluorine atoms can be particularly useful in the treatment and/or modification of surfaces, for example as hydrophobizing and oleophobizing agent, being able to exhibit a corrosion-inhibiting function.
The following examples illustrate the invention without limiting the scope thereof.
5.0 g (4.67×10−2 mol) of VPA, 0.29 g (1.77×10−3 mol) of azobisisobutyronitrile (AIBN), 0.18 g (7.08×10−4 mol) of iodine I2 and 10 g of acetonitrile are introduced into a 100 ml two-necked round-bottom flask covered with a film of aluminum and equipped with a reflux condenser. The mixture is degassed using argon for 10 min at 0° C. and then placed at 80° C. with magnetic stirring. The reaction is halted when the monomer is no longer consumed. The maximum conversion achieved is 50% (measured by 31P NMR). The polymer is obtained by precipitating from ethyl acetate, then filtered off and stored in the dark at 0° C. A white powder is obtained.
GPC analyses in water were carried out on the product obtained and on two other polymers synthesized in the presence of variable concentrations of iodine I2. The GPC analyses clearly show that the molar masses are controlled by the level of iodine. They increase as the starting concentration of I2 decreases. Furthermore, an elemental analysis was carried out on a sample for which the starting concentration of I2 corresponded to a polymer comprising 30 VPA units. The elemental analysis indeed confirms the value of the number-average degree of polymerization targeted. In addition, the elemental analysis confirms the presence of iodine.
5.0 g (4.67×10−2 mol) of VPA, 0.08 g (5.09×10−4 mol) of AIBN, 0.69 g (1.54×10−3 mol) of C6F13I and 10 g of acetonitrile are introduced into a 100 ml two-necked round-bottom flask covered with a film of aluminum and equipped with a reflux condenser. The mixture is degassed using argon for 10 min at 0° C., followed by three vacuum/argon cycles, and then placed at 70° C. with magnetic stirring. The reaction is halted when the monomer is no longer consumed. The maximum conversion achieved is 70% (measured by 31P NMR). The polymer is obtained by precipitating from acetone, then filtered off and stored in the dark at 0° C. A white powder is obtained.
19F NMR, performed in deuterated water, clearly shows the presence of the signals of the C6F13— group. Only the signal of the CF2 in the α position with regard to the iodine atom has disappeared at −60 ppm and a new signal characterizing the CF2 in the a position with regard to the CH2 of the VPA appears at −112 ppm. In addition, a Maldi-Tof analysis corroborates these results since the expected structure C6F13(VPA)n-1-CH═CHPO3H2 is observed (H1 is eliminated at the chain end during the analysis). The very good dispersibility in water of the polymer formed is also characteristic of the formation of an amphiphilic polymer.
5.0 g (4.67×10−2 mol) of VPA, 0.08 g (5.09×10−4 mol) of AIBN, 0.33 g (1.54×10−3 mol) of CH3CH(CO2CH3)I and 10 g of acetonitrile are introduced into a 100 ml two-necked round-bottom flask covered with a film of aluminum and equipped with a reflux condenser. The mixture is degassed using argon for 10 min at 0° C., followed by three vacuum/argon cycles, and then placed at 70° C. with magnetic stirring. The reaction is halted when the monomer is no longer consumed. The maximum conversion achieved is 70% (measured by 31P NMR). The polymer is obtained by precipitating from acetone, then filtered off and stored in the dark at 0° C. A white powder is obtained.
The FTIR and 1H NMR analyses characterize the presence of the ester functional group of the transfer agent at the chain end of the VPA oligomers. Specifically, the FTIR analysis shows the presence of the vibration of the carbonyl at 1710 cm−1. 1H NMR characterizes the peak of the methyl in the α position with regard to the carbonyl group. Finally, a kinetic study by gas chromatography shows that the iodine-comprising agent is consumed during the reaction.
2.0 g (2.22×10−2 mol) of methyl acrylate (MA), 0.379 g (2.31×10−3 mol) of azobisisobutyronitrile (AIBN), 0.294 g (1.16×10−3 mol) of iodine I2 and 10 g of toluene are introduced into a 100 ml two-necked round-bottom flask covered with a film of aluminum and equipped with a reflux condenser. The mixture is degassed using argon for 10 min at 0° C. and then placed at 80° C. with magnetic stirring. The reaction is halted before complete conversion of the MA monomer. The crude reaction product is analyzed by GPC (eluent THF) and a molar mass Mn of 1100 g/mol (PMMA standards) is obtained with a polydispersity index Mw/Mn of 1.6. The 1H NMR analysis shows the presence of the iodine atom at the chain end of the polymethyl acrylate by the peak at 4.5 ppm of the proton —CH— in the α position with regard to the iodine atom. The residual methyl acrylate is completely evaporated under vacuum before the following polymerization stage.
1.54 g (1.54×10−3 mol) of the polymethyl acrylate functionalized by an end iodine atom, 5.0 g (4.67×10−2 mol) of VPA, 0.08 g (5.09×10−4 mol) of AIBN and 10 g of toluene are introduced into a 100 ml two-necked round-bottom flask covered with a film of aluminum and equipped with a reflux condenser. The mixture is degassed using argon for 10 min at 0° C., followed by three vacuum/argon cycles, and then placed at 70° C. with magnetic stirring. The reaction is halted when the monomer is no longer consumed. The maximum conversion achieved is 50% (measured by 31P NMR). After complete evaporation of the toluene under vacuum and addition of water, the polymer obtained forms a stable aqueous dispersion.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06 00715 | Jan 2006 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP07/50704 | 1/24/2007 | WO | 00 | 5/22/2009 |
