Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F293/00—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule
  • C08F293/005—Macromolecular compounds obtained by polymerisation on to a macromolecule having groups capable of inducing the formation of new polymer chains bound exclusively at one or both ends of the starting macromolecule using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/001—Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer

Definitions

• the present invention relates to a process for preparing a polymeric material comprising a multiblock copolymer obtained by controlled radical polymerization.
• the present invention also relates to a nanostructuring and nanostructured polymeric material which can be used as a thermoplastic material or as a reinforcing additive or rheological additive of host matrices, this material being able to find its application in the manufacture of transparent parts having improved mechanical properties. .
• the general field of the invention is therefore that of polymeric materials, and more particularly nanostructured polymeric materials.
• Nanostructured polymeric materials are materials organized into domains with dimensions smaller than 100 nm. Such materials have the advantage of remaining transparent and, in case of introduction of said material into a host matrix, not to disturb the properties thereof. STATE OF THE ART
• the nanostructured domains can be produced by polymer particles dispersed in another polymer constituting a host matrix, said particles having a size defining the size of the domains. These particles are obtained by an emulsion polymerization process. However, it turns out that it is difficult, on an industrial scale, to obtain, to this day, by this process particles of such sizes because of the instability of the emulsions. In addition, the particle distribution is strongly conditioned by the mixing step, which, if not carried out carefully, may hinder the final physicochemical properties.
• Block copolymers are generally obtained by so-called living polymerization techniques, that is to say techniques where termination reactions tend to be limited, so that the polymer chains continue to grow as long as they occur. Monomers remain available.
• anionic polymerization dedicated to the synthesis of copolymers from ethylenic monomers comprising one or more electroattractive substituents, such as a copolymer of the polystyrene-butadiene type;
• cationic polymerization dedicated to the synthesis of copolymers from ethylenic monomers comprising one or more electron-donor substituents, such as copolymers of the polyether type.
• SFRP stable free radical polymerization
• control agent The role of the control agent is to slow the biradical termination reactions so as to favor the growth of the chains by addition to free monomer. However, when one tries to push these polymerizations towards high Conversions, termination reactions necessarily take place. Gradually decreasing the ratio between propagating chains and control agent considerably slows down the kinetics of polymerization.
• X (M 1 ) and x (M 2 ) respectively represent the volume fraction of M 1 and the volume fraction of
• the glass transition temperature of the second block is affected by the presence of monomers from the first block. This results in a deterioration of physico-chemical and mechanical properties compared to what one would expect from a pure diblock polymer.
• the inventors have therefore set themselves the objective of developing a process for preparing a polymeric material comprising a multiblock copolymer which does not have the drawbacks of the processes of the prior art mentioned above. They have discovered, surprisingly, that by performing a particular step after the blocking step, it was possible to overcome the above mentioned disadvantages.
• the invention thus relates, according to a first object, to a process for preparing a polymeric material comprising a multiblock copolymer comprising n blocks, n being an integer greater than or equal to 2, said method comprising at least one cycle of steps comprising:
• step a) a step of synthesizing a block by controlled radical polymerization of one or more radically polymerizable monomers; b) a polymerization step of the monomers not converted in step a) into a polymer having a number average molecular weight less than the number average molecular weight of said block; said cycle of steps being performed at least for the
• (n-1) first blocks.
• the cycle of steps is performed for the n blocks.
• the monomers that are not converted during each step a) are converted into a polymer having a number-average molecular mass less than the number-average molecular mass of said block, of identical chemical nature. block audit.
• the polymer produced is thus compatible with the block produced previously.
• polymer compatible with the block is meant a polymer capable of interacting with said block, so as to be miscible in said block.
• the invention thus provides a nanostructured and nanostructured polymeric material having physicochemical and mechanical properties, such as the glass transition temperature, inherent to each block, unaltered compared to those of a pure block.
• This method also proves to be an easy and inexpensive implementation method and therefore very advantageous for use in an industrial environment.
• the preparation method of the invention comprises successively: a step of preparing a first block from one or more monomers by controlled radical polymerization;
• the invention relates to a method for preparing a polymeric material comprising a multiblock copolymer, it is particularly applicable to the preparation of a polymeric material comprising a copolymer comprising at least one block A and at least one block B.
• the application therefore also relates to a process for preparing a polymeric material comprising a copolymer comprising at least one block A and at least one block B, said process comprising successively:
• step 2) a step of polymerization of the residual monomer or monomers not converted during step 1), to form a polymer of chemical nature identical to the block A but of number average molecular mass less than that of the block A and, generally, polydispersity index higher than that of block A; 3) a step of adding to the medium resulting from the previous steps 1) and 2) of one or more radically polymerizable monomers precursors of block B;
• step 4 optionally a step of polymerization of the residual monomer or monomers not converted during step 4), to form a polymer of chemical nature identical to block B but of number average molecular weight less than that of block B and, generally , of polydispersity index greater than that of block B.
• the synthesis of the blocks of the multiblock copolymers of the invention is carried out by controlled radical polymerization at a temperature appropriate to the type of PRC chosen (according to whether it is SFRP, ATRP or RAFT) and to the type of monomers chosen.
• the radical polymerization technique used for each step a) or for steps 1) and 4) is the SFRP polymerization preferably carried out in the presence of at least one alkoxyamine, this type of compound ensuring, at the same time, the role of initiating agent and controlling agent.
• Alkoxyamines advantageously used according to the invention may be chosen from the monoalkoxyamines of formula (I):
• R 1 and R 3 which may be identical or different, represent a linear or branched alkyl group having a number of carbon atoms ranging from 1 to 3;
• R.2 represents a hydrogen atom, an alkali metal, such as Li, Na, K, an ammonium ion such as NH 4 + , NBu 4 + , NHBU 3 "1" , a linear or branched alkyl group, having a number of carbon atoms ranging from 1 to 8, a phenyl group.
• a particular example of monoalkoxyamine is that corresponding to the following formula:
• Alkoxyamines which can advantageously be used according to the invention may also be polyalkoxyamines resulting from a process comprising reacting one or more alkoxyamines of the following formula (I):
• R 1 and R 3 which may be identical or different, represent a linear or branched alkyl group having a number of carbon atoms ranging from 1 to 3;
• R.2 representing a hydrogen atom, a linear or branched alkyl group having a number of carbon atoms ranging from 1 to 8, a phenyl group, an alkali metal such as Li, Na, K, an ion ammonium such as NH 4 + , NHBU 3 + ; preferably, R 1 being CH 3 and R 2 being H; with at least one polyunsaturated compound of formula (II):
• Z represents an aryl group or a group of formula in which Zi represents a polyfunctional structure derived for example from a polyol compound
• X is an oxygen atom, a nitrogen atom carrying a carbon group or an oxygen atom
• n is an integer greater than or equal to 2
• solvent preferably chosen from alcohols such as ethanol, aromatic solvents, chlorinated solvents, aprotic polar ethers and solvents, at a temperature ranging, in general, from at 90 ° C., preferably from 25 ° to 80 ° C., the molar ratio between monalcoxyamine (s) of formula (I) and polyunsaturated compound (s) of formula (II) ranging from 1.5 to 1.5n preferably from n to 1.25 n, this step possibly being followed by a step of evaporation of the possible solvent (s).
• solvent preferably chosen from alcohols such as ethanol, aromatic solvents, chlorinated solvents, aprotic polar ethers and solvents
• the polyunsaturated compound of formula (II) may be chosen from polyfunctional vinylbenzenes (Z being then an aryl group) or from polyfunctional acrylic derivatives (Z being then a group of formula Zi- [XC (O) J n ) -
• the polyunsaturated compound is divinylbenzene, trivinylbenzene, ethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, cyclohexane dimethanol diacrylate diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol diacrylates (sold by Sartomer under the names SR259, SR344, SR610) and hexanediol di
• the polyalkoxyamines thus produced have the following formula (III):
• n, Ri, R 2 and R 3 , Z have the same meanings as those given above.
• polyalkoxyamine according to the general definition given above is polyalkoxyamine corresponding to the following formula:
• the alkoxyamines of formula (I) and / or the polyalkoxyamines of formula (III) play both the role of initiator (and control agent) and emulsifier agent; thus, the surfactant properties of the water-soluble alkoxyamines of formula (I) and / or polyalkoxyamines of formula (III) make it possible to moderate or even to avoid the use of other surfactants.
• alkoxyamines of formula (I) and / or the polyalkoxyamines of formula (III) are water-soluble.
• water-soluble alkoxyamine or “water-soluble polyalkoxyamine” means any alkoxyamine of formula (I) or polyalkoxyamine of formula (III) whose solubility in the water phase or (water / water-miscible compound) is from minus 1 g / 1 at 25 ° C.
• the alkoxyamine or polyalkoxyamine may be introduced into the polymerization medium (i.e., during each step a) or steps 1) and 4) at a rate of from 0.01% to 10%, preferably 0.1 to 5% by weight relative to the mass of monomer (s).
• monomer any monomer polymerizable or copolymerisable radical.
• monomer covers, of course, mixtures of several monomers.
• the monomers used for producing the blocks may be chosen from monomers having a carbon-carbon double bond capable of radical polymerization, such as vinyl, vinylidene, diene and olefinic, allylic, acrylic, methacrylic monomers, and the like.
• the monomers used can in particular be chosen from vinylaromatic monomers such as styrene or substituted styrenes, especially ⁇ -methylstyrene and sodium styrene sulphonate, dienes such as butadiene or isoprene, and acrylic monomers such as acrylic acid or its salts, alkyl, cycloalkyl or aryl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate or phenyl acrylate, hydroxyalkyl acrylates such as acrylate 2-hydroxyethyl acrylates, ether alkyl acrylates such as 2-methoxyethyl acrylate, alkoxy- or aryloxypolyalkyleneglycol acrylates such as methoxypolyethylene glycol acrylates, ethoxypolyethylene glycol acrylates, methoxypolypropylene glycol acrylates,
• aminoalkyl acrylates such as 2- (dimethylamino) ethyl acrylate (ADAME), amino salt acrylates such as [2- (acryloyloxy) ethyl] trimethylammonium chloride or sulfate or [2- (acryloyloxy) ethyl] dimethylbenzylammonium chloride or sulfate, fluorinated acrylates, silyl acrylates, acrylates phosphors such as alkylene glycol phosphate acrylates, methacrylic monomers such as methacrylic acid or its salts, alkyl, cycloalkyl, alkenyl or aryl methacrylates such as methyl methacrylate, lauryl methacrylate, cyclohexyl, allyl or phenyl, hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate or 2-hydroxy
• emulsifying agent that is to say a surfactant allowing f stabilize the emulsion, provided that said emulsifying agent is not an alkoxyamine as defined above. All usual emulsifier in this type of emulsion can be used f.
• the emulsifying agent may be anionic, cationic or nonionic.
• the emulsifying agent may be an amphoteric or quaternary or fluorinated surfactant. It may be chosen from alkyl or aryl sulphates, alkyl or aryl sulphonates, fatty acid salts, polyvinyl alcohols and polyethoxylated fatty alcohols.
• the emulsifying agent can be chosen from the following list:
• the emulsifying agent may also be an amphiphilic block or random or graft copolymer, such as copolymers of sodium styrene sulphonate and in particular sodium polystyrene-b-poly (sodium styrene sulphonate) or any amphiphilic copolymer prepared by any other polymerization.
• the emulsifying agent may be introduced into the polymerization medium in a proportion of 0.1% to 10% by weight relative to the mass of monomer (s).
• the polymerization steps for producing the blocks are performed at a temperature appropriate to the type of monomers used in the constitution of the block.
• the polymerization temperatures depend on the constituent monomers of the block.
• a temperature greater than 50 ° C. preferably less than 130 ° C., more preferably ranging from 90 ° C. to 125 ° C.
• a temperature of greater than 50 ° C. preferably less than 200 ° C., is preferably chosen, preferably ranging from 90 ° C. to 175 ° C.
• the invention generally has a number average molecular weight of from 1000 to 6 g / mol and a polydispersity index of less than 2.
• the degree of conversion of the monomers or monomer mixture constituting the blocks generally depends on the manufacturing time devoted to the block and is generally set so as to obtain a block of average molar mass in predetermined number.
• a polymerization step of the monomer (s) unconverted (s) constituent of the block which has just been synthesized is provided between two steps of preparation of two adjacent blocks (that is to say between two steps a) of two successive cycles or between steps 1) and 4)) and possibly after the step of preparation of last block (that is to say the end block) (corresponding to steps a) of two successive cycles or in step 5)).
• This polymerization is carried out, for each step b) or for steps 2) and 5), generally by so-called conventional radical polymerization, namely by adding to the medium in which the block has just been produced, a so-called conventional radical polymerization initiator chosen, generally, from the peroxide compounds (such as a peroxide compound of the Luperox TM range, the persulfate compounds (such as sodium persulfate, potassium persulfate, ammonium persulfate), azo compounds (such as bis-azidoisobutyronitrile, titled AiBN, 2,2'-azobis (2-amidinopropane) dihydrochloride and the metal and ammoniacal salts of 4, 4'-azobis (4-cyanopentanoic acid)), redox compounds (such as the persulfate (sodium, potassium or ammonium / vitamin C) pair, the persulfate / metabisulphite pair of sodium or potassium, the water pair Oxygenated / ferrous
• each either b) or for steps 2) and 5) is preferably chosen so as to be at least 20 ° C. lower than that for polymerization of the block which has just been polymerized (ie say in steps a) or steps 1) and 4)).
• the fact of decreasing the temperature makes it possible to preserve the block previously synthesized in the form of a living polymer, without however continuing the polymerization thereof.
• the polymer obtained after steps b) or steps 2) and optionally 5) has a number average molecular weight less than that of the block synthesized just before and, generally, also a polydispersity index greater than that of the synthesized block just before.
• the condition on the number average molecular weight is essential for the final resulting material (polymer blocks + polymers resulting from the polymerization of the unconverted monomers of each of the blocks) to be nanostructuring, these conditions allowing the polymers produced by conventional radical polymerization to remain compatible with block copolymer blocks produced by controlled radical polymerization.
• a transfer agent i.e. an agent capable of regulating the molecular weight of the polymer chains produced
• this transfer agent possibly being chosen from: sulfur compounds, for example mercaptan compounds comprising at least 4 carbon atoms, such as butane mercaptan, dodecyl mercaptan, terdodecyl mercaptan, disulfide compounds;
• hindered phenols such as tertbutyl catechol
• secondary alcohols such as isopropanol
• transfer agents used for radical polymerization of the RAFT type such as trithiocarbonates (in particular dibenzyltrithiocarbonate), xanthates, dithioesters, dithiocarbamates. It may also be provided, so that the polymers produced in these steps have particular properties, to add, in addition to the polymerization initiator, monomers different from those of unconverted monomers.
• the method of the invention makes it possible to obtain a polymeric material comprising a multiblock copolymer comprising n blocks connected to each other by a covalent bond, n being an integer greater than or equal to 2, and for at least each of ( n-1) first blocks, polymer chains formed by unconverted monomers forming part of the corresponding block, said chains having a number average molecular weight less than that of the corresponding block and, generally, a polydispersity index greater than that of the corresponding block.
• this process is particularly suitable for the preparation of a polymeric material comprising a diblock copolymer A-B, such as a copolymer (n-butyl acrylate / methyl methacrylate).
• a polymeric material comprising at least one diblock copolymer AB: after the first step, a mixture comprising preamble polymer chains prefiguring Block A of the block copolymer and unconverted monomers; after the second step, a mixture comprising the rebootable polymer chains of the first step and polymer chains resulting from the polymerization of the unconverted monomers of the first step; after the fourth step, a mixture comprising the diblock copolymer consisting of block A and block B linked together by covalent bonding, polymer chains resulting from the polymerization of the unconverted monomers of the first stage, monomers that are not converted during the course of the fourth step; after the fifth step, a mixture comprising the AB diblock copolymer, polymer chains resulting from the polymerization of the residual monomers of the first step and polymer chains resulting from the polymerization of the unconverted monomers during the fourth step.
• the said chains are compatible with the block A.
• the chains resulting from the fifth step because of their number average molecular weight, are either compatible with the block B, or it is the block B which is compatible with these chains.
• the method of the invention therefore leads to a nanostructuring and nanostructured material.
• the conditions for carrying out the process for preparing a polymeric material comprising an AB diblock copolymer are similar to those already described in the general part relating to materials comprising a multiblock copolymer.
• the advantageous operating conditions as well as the advantageous characteristics of the products resulting from the first step (step 1) can be the following ones:
• an SFRP type polymerization for the synthesis of the first block, preferably using as initiator alkoxyamines or polyalkoxyamines as defined above;
• monomers used for the synthesis of the first block chosen from acrylic and methacrylic derivatives, styrene derivatives as defined above; a polymerization temperature greater than 50 ° C. and less than 130 ° C., preferably ranging from 90 ° C. to 125 ° C.; a conversion achieved, preferably, ranging from 60% to 95%, more preferably ranging from 65 to 90%;
• step 2 a number-average molecular mass of the first block, preferably ranging from 5000 g / mol to 500000 g / mol.
• the advantageous operating conditions of the second step (step 2) can be as follows:
• a polymerization temperature ranging from 30 ° C. to 100 ° C., preferably from 50 ° C. to 80 ° C .; the presence of transfer agents for regulating the molecular mass of the chains produced during this step, said agents being preferably chosen from mercaptan compounds having at least 4 carbon atoms, such as butane mercaptan and dodecyl mercaptan, terdodecyl mercaptan, disulfides, hindered phenols such as terbutyl catechol, secondary alcohols such as isopropanol, RAFT transfer agents such as trithiocarbonates (especially dibenzytrithiocarbonate), xantates, dithioesters and the like.
• transfer agents for regulating the molecular mass of the chains produced during this step, said agents being preferably chosen from mercaptan compounds having at least 4 carbon atoms, such as butane mercaptan and dodecyl mercaptan, terdo
• dithiocarbamates the addition of monomers other than the residual monomers in a proportion of 0 to 10% of the monomers converted during this step, preferably from 0 to 5%, these monomers being able to be chosen from acrylic acid, methacrylic acid and their esters or amides such as in particular the esters of glycidyl, 2-ethanolamine, polyethylene glycol, 3-propenol, or in particular dimethyl acrylamide.
• Other monomers such as butadiene, maleic anhydride, vinyl acetate, halogen-functional monomers such as vinyl chloride, vinylidene chloride, vinylidene difluoride, vinyl tetrafluoride can be copolymerized during this synthesis step.
• the conversion rate of the unconverted monomers can be up to 100% over a period of a few hours (for example, a duration of 4 hours).
• the advantageous operating conditions as well as the advantageous characteristics of the products resulting from the fourth step (step 4)) can be the following ones:
• monomers used for the synthesis of the second block chosen from acrylic and methacrylic derivatives, styrene derivatives as defined above; a polymerization temperature greater than 50 ° C. and less than 200 ° C., preferably ranging from 90 ° C. to 175 ° C.; a conversion achieved, preferably ranging from 45% to 95%, more preferably from 50 to 90%.
• a polymeric material prepared according to the invention is a material comprising a diblock copolymer (n-butyl polyacrylate-b-polymethyl methacrylate).
• the process of the invention can be applied to bulk polymerization methods, organic solvent (such as toluene), emulsion, suspension.
• organic solvent such as toluene
• emulsion emulsion
• suspension emulsion
• Each step of the process can be carried out in the same reactor via a "batch” process (or batch process), or in different reactors optionally in semi-continuous or continuous processes.
• the invention also relates to a polymeric material obtainable by the method described above, comprising a multiblock copolymer comprising n blocks connected to each other by covalent bond, n being an integer greater than or equal to 2, and for at least each of the (n-1) first blocks, preferably, for each of the n blocks, polymer chains formed of the residual monomers forming part of the corresponding block, said chains having a number average molecular mass less than of the corresponding block and, generally, a polydispersity index greater than that of the corresponding block.
• the materials benefit from the physico-chemical properties related to its nanostructuring such as, for example, its transparency, its resistance to cracking or its ability to encapsulate other bodies.
• another object of the invention is the use of the material as defined above as a thermoplastic material. Because of its transparency properties and its mechanical properties, such as an excellent impact value, the polymeric material according to the invention therefore finds its application in the field of luminaires, automobiles (to constitute, for example, optical headlights), construction, domestic applications (to constitute, for example, display points). It can also find application in the field of cosmetics. It can be specified that the materials of the invention find their application in all known fields of application of polymethyl methacrylate.
• Another object of the invention is the use of the material as defined above as a nanostructuring additive of polymer matrices.
• polymer matrices are for example thermoplastic polymers (polystyrene, polymethyl methacrylate, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyamides, polypropylene, polyethylene, ...), thermosetting polymers (poly epoxides, poly urethanes, unsaturated polyesters. ..), crosslinked matrices (such as rubbers, polyethylenes, crosslinked styrene - butadiene resins) and mixtures thereof.
• Nanostructuring or nanostructured additives make it possible to to give these matrices improved use properties.
• Another subject of the invention is the use of the material as defined above as a reinforcing and / or rheoplasticizing additive of polymer matrices. He therefore finds, as an additive, its application in the field of aeronautics, electricity, electronics, thermostructural adhesives, sports equipment, coatings. Compared to pure block copolymers, the presence in this material of low molecular weight chains will induce better fluidity during the processing steps of these host matrices such as injection and thermoforming.
• FIG. 1 represents a photograph obtained by atomic force microscopy of a material of example 3;
• FIG. 2 represents a photograph obtained by atomic force microscopy of a material of example 4.
• FIG. 3 represents a photograph obtained by atomic force microscopy of a material of example 6.
• the initiators of the alkoxyamine type were prepared beforehand, as follows:
• This initiator is prepared as follows:
• This initiator is prepared according to the protocol described in FR 2861394.
• This example presents the preparation of a first bulk n-butyl polyacrylate block by a bulk process, which will be used for the following Examples 2 to 5.
• the mixture is then cooled to room temperature in 15 minutes so as to quench the reaction mixture.
• a solution of polymer in n-butyl acrylate is recovered by a bottom valve.
• a solids measurement indicates that there was a 60% conversion, i.e., 60% of the n-butyl acrylate present in the initial mixture polymerized.
• the intermediate n-butyl polyacrylate is characterized by size exclusion chromatography, which provides the following data:
• This polymer solution is used as such for Examples 2 to 5.
• This example illustrates the preparation of a diblock copolymer by controlled radical polymerization, by a process taking place in mass / organic solvent according to the prior art.
• the preparation protocol is as follows:
• Example 2 After cleaning with toluene, the same reactor as in Example 1 is charged with 2.5 kg of the solution obtained in Example 1 and 4 kg of methyl methacrylate, the initial mixture thus comprising 1.5 kg of polyacrylate. of living n-butyl, 1 kg of residual n-butyl acrylate and 4 kg of methyl methacrylate. The whole is diluted with 2.5 kg of toluene. After putting under nitrogen, the reactor is heated to 105 ° C. for one hour and then at 120 ° C. for one hour before being cooled in 15 minutes at room temperature. The solids content is 55%, which corresponds to a conversion of the monomers (methyl methacrylate + residual n-butyl acrylate) of 70%.
• the chemical composition of the copolymer is determined by 1 H NMR and gives the following results: polymethyl methacrylate: 55% (by weight); n-butyl polyacrylate: 45% (by weight);
• the polymethyl methacrylate block comprises 16% by weight of n-butyl acrylate.
• This example illustrates the preparation of a polymeric material comprising a diblock copolymer by controlled radical polymerization, by a process taking place in mass / solvent under conditions not in accordance with the invention.
• the preparation protocol is as follows:
• the final mixture has a solids content of 65%, ie a conversion of 86% of the residual n-butyl acrylate.
• the analysis by gas chromatography indicates a number average molecular weight Mn of 28,500 and a polydispersity index Ip of 6.
• the final conversion is 50% methyl methacrylate.
• the composition of the product is as follows:
• n-butyl polyacrylate 40% of n-butyl polyacrylate, 24% of which is bound to the polymethyl methacrylate block and 16% of n-butyl polyacrylate not bound to the block.
• the highest Tg of the product analyzed by DMA is HO 0 C, which is a Tg according to the invention.
• n-butyl acrylate agglomerates in nodules of the order of several hundred nanometers which shows that some of the free chains generated during the second step are not soluble in the otherwise nanostructured network of the block copolymer. This organization explains the slight veil observed in the material in Figure 1.
• This example illustrates the preparation of a polymeric material comprising a diblock copolymer by controlled radical polymerization in solution according to the conditions of the invention.
• the final conversion is 55% of methyl methacrylate.
• the composition of the material in solution is as follows: 62% of polymethyl methacrylate;
• n-butyl polyacrylate 38% of n-butyl polyacrylate, including 22.8% of butyl polyacrylate bound to the polymethyl methacrylate block and 15.2% of non-block bound n-butyl polyacrylate.
• the highest Tg of the product analyzed by DMA is HO 0 C, which is in accordance with the invention. It is observed by atomic force microscopy that, on scales of several microns, the product is well nanostructured. The n-butyl polyacrylate produced in the presence of transfer agent is well soluble in the nanodomains of the block copolymer (see FIG. 2). As expected, the product obtained is very transparent.
• the solution is injected at a flow rate of 2 kg / h in a 5 liter reactor heated to 155 0 C and with a continuous extraction system feeding a devolatilizing extruder through transfer lines heated at 9O 0 C.
• the extraction rate corresponds to the introduction rate.
• the flow rate is maintained at this rate until the solid content inside the reactor reaches a value between 50 and 55%. From this moment, the flow rate is adjusted so that the temperature in the reactor is 163 ° C. ⁇ 5 ° C. (the flow acceleration serves to lower the temperature, a slowing increases it).
• the high Tg of the product analyzed by DMA is 108 ° C., which is in accordance with the invention.
• the mechanical tests of the material show a resilience in the notch impact test of 82 kJ / m 2 , a modulus of 1680 MPa, comparable to the values found in the same tests for commercially impacted polymethyl methacrylate grades.
• This example illustrates the preparation of a polymeric material comprising a diblock polymer by controlled radical polymerization in emulsion according to the conditions of the invention.
• n-butyl acrylate 143.4 g (1.12 mol) of n-butyl acrylate are introduced in one go.
• the reaction medium is then degassed several times with nitrogen, stirred at room temperature for 30 minutes, then heated to 120 ° C. This temperature is maintained by thermal regulation for about 1H30, until the conversion of the acrylate n-butyl reaches 80%.
• n-butyl acrylate The conversion of n-butyl acrylate is evaluated at 80% by weight by gravimetry.
• the molecular weights of the difunctionalized poly (n-butyl acrylate) obtained by Radical Polymerization Controlled in Polystyrene Equivalent are as follows:
• Peak molecular weight Mw 50,000 g / mol
• n-butyl acrylate The conversion of n-butyl acrylate is then evaluated at 98% by weight by gravimetry.
• the molecular weights of poly (n-butyl acrylate) obtained by controlled radical polymerization and conventional radical polymerization in polystyrene equivalents are as follows:
• the solids content of the latex is 17%.
• the residual methyl methacrylate is then converted by a conventional radical polymerization process as described in the step below.
• the solids content of the latex obtained is 30%.
• Example 5 The product obtained in Example 5 is dissolved at a rate of 10% by weight in a mixture
• the crosslinking reaction is initiated at 135 ° C. and the cooking is continued for 2 hours.
• thermoset material After baking, the thermoset material is transparent. Transmission electron microscopy analysis reveals that this material is nanostructured.
• the copolymer is dispersed in the form of particles clear, surrounded by a dark crown of irregular thickness, shape and variable sizes. These domains are of the order of 10 nm.
• the core is butyl polyacrylate
• the bark is the butyl polymethacrylate domains, which have good affinity with the epoxy matrix (see Figure 3).

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