Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/67—Unsaturated compounds having active hydrogen
  • C08G18/69—Polymers of conjugated dienes
• • 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
  • C08F136/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F136/02—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F136/04—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
• • 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
  • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
• • 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
• • 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
  • C08F4/00—Polymerisation catalysts
  • C08F4/28—Oxygen or compounds releasing free oxygen

Definitions

• the present invention relates to a process for the preparation of telechelic 1,3-diene oligomers by radical polymerization of 1,3-dienes in the presence of a stable free radical.
• the invention also relates, as new products, to said telechelic 1,3-diene oligomers and their use for obtaining di- or multiblock copolymers.
• telechelic 1,3-diene oligomers By telechelic 1,3-diene oligomers is meant according to the present invention oligomers carrying at one of their ends (or at both) functional groups, capable of reacting with other molecules.
• a common method for obtaining such oligomers is to carry out radical polymerization of the 1,3-dienes by initiating the polymerization with a heat-sensitive radical initiator such as hydrogen peroxide (H2O2) or an azodinitrile compound.
• a heat-sensitive radical initiator such as hydrogen peroxide (H2O2) or an azodinitrile compound.
• H2O2 hydrogen peroxide
• azodinitrile compound an azodinitrile compound
• the dihydroxytelechelic 1,3-butadiene oligomers are obtained industrially by radical polymerization of butadiene initiated by hydrogen peroxide in an alcoholic medium (US 3,392, 1,18 - US 3,427,366).
• an alcoholic medium US 3,392, 1,18 - US 3,427,366
• Stable free radicals are compounds which have been widely used in the case of radical polymerization for the study of the first stages of addition. That is to say, they made it possible to better understand the priming stage: I * + M ⁇ IM * where I is the radical resulting from the initiator and M the monomer, by immediately blocking the growth of the IM * radicals.
• Nitroxides have also been used in radical polymerization to better control the propagation step and to limit reactions of conventional endings. The following mechanism is commonly proposed:
• I is the radical resulting from the initiator, M the monomer and T the nitroxide.
• the polymerization time can be considerably extended. This balance is displaced by the nature of T, the solvent and the temperature. However, to limit the termination reactions, the concentration of active species must remain low.
• the polystyrenes obtained have a narrow polymolecularity (1, 1 to 2) and high molecular weights (approximately 100,000).
• the following references also relate to the radical polymerization of monomers such as polyolefins (US 5,449,724), alkyl (meth) acrylates (US 5,412,047) in the presence of a nitroxide.
• 1,3-dienes which can be used according to the present invention, mention may be made of 1,3-butadiene, 2,3-dimethyl1,3-butadiene, isoprene, 2-chloro1,3-butadiene .
• the present invention relates very particularly to the radical polymerization of 1,3-butadiene.
• azodinitriles which can be used according to the present invention as a polymerization initiator, there may be mentioned: - 2,2'-azobisisobutyronitrile,
• 2,2'-azobisisobutyronitrile designated below by AIBN
• AIBN 2,2'-azobisisobutyronitrile
• stable free radicals which can be used according to the present invention
• the stable nitroxide radical is chosen from the compounds represented by the following formulas:
• R1, R2, R3, R4, R '1 and R'2, identical or different represent a halogen atom such as chlorine or bromine, a linear, branched or cyclic, saturated or unsaturated hydrocarbon group having a carbon number ranging from 1 to 10 such as an alkyl, cycloalkyl or phenyl radical, or an ester group - COOR or an alkoxyl group -OR, or a phosphate group -P (O) (OR) 2 in which R is a saturated aliphatic radical having a carbon number ranging from 1 to 3; and in which R5, R6, R7, R8, R9 and R10, identical or different, may have the same meaning as R1, R2, R3, R4, R * 1 and R'2 or else represent a hydrogen atom, a hydroxyl group - OH or an acid group such as -COOH, -P (O) (OH) 2 or -SO3H.
• a halogen atom such as chlorine or bromine
• the polymerization is carried out in a dispersed medium by mixing the initiator and the stable free radical in a solvent and then the 1,3-diene is introduced into the reaction medium having been purged and / or degassed. .
• the reaction is carried out under pressures ranging from 5 bars to 50 bars and, preferably, between 10 bars and 30 bars.
• the reaction medium is brought to a temperature between 100 ° C and 150 ° C and, preferably, between 1 10 ° C and 135 ° C; for a duration which is at least equal to 1 hour and, preferably between 1 h 30 min and 6 hours.
• molar amounts of initiator are used between 0.1% and 10% and preferably between 0.2% and 4% relative to the 1,3-diene used.
• molar quantities of stable free radical are used such that the stable free radical / initiator molar ratio is between 0.05 and 5 and preferably between 0.1 and 2.5.
• solvents which can be used according to the present invention, mention may be made of alkanes; aromatic solvents such as benzene, toluene; alcohols such as ethanol, propanol, isopropanol, cyclohexanol; ketones such as acetone, methyl ethyl ketone; ethers such as dioxane; glycols and glycol ethers such as ethylene glycol dimethyl ether (giyme) or a mixture of at least two of the above-mentioned compounds.
• the initiator is hydrogen peroxide, which is generally in aqueous solution, it is preferred to use as solvent alcohols such as isopropanol or ketones such as methyl ethyl ketone.
• the initiator is an azodinitrile
• aromatic solvents such as benzene or toluene.
• the polymerization conditions, and in particular the duration, the temperature, the amounts of the reactants, in particular of initiator and of stable free radical it is possible to obtain average molecular masses in number Mn different and different conversion rates.
• the number-average molecular mass Mn and the yield increase when the temperature increases for a fixed polymerization time.
• the functionality in stable free radical is close to 1.
• the telechelic 1,3-diene oligomers obtained have the following general formula:
• I represents either a hydroxyl -OH in the case where the initiator is
• H 2 ° 2 ' is a monovalent organic residue comprising a nitrile group -CN, in the case where the initiator is an azodinitrile.
• this initiator is AIBN
• I NC-C (CH 3 ) 2 -.
• M represents a divalent residue of 1, 3-diene.
• 1, 3-dienes can polymerize in 1, 4 and in 1, 2, we will have the configurations, cis and trans in the case of polymerization in 1, 4:
• CH CH - cis configuration: -CH 2 ' ⁇ CH-
• the method according to the present invention makes it possible to obtain telechelic 1,3-diene oligomers having number-average molar masses Mn at most equal to 30,000 and, preferably, between 500 and 10,000.
• the polymolecularity Mw / Mn is less than 2 and preferably between 1, 1 and
• This polymolecularity is less than that obtained, all other things being equal with a polymerization in the absence of a stable free radical.
• the telechelic 1,3-diene oligomers of structure (I) can be reduced in particular by a zinc / acetic acid system, a conventional method used for the reduction of alkoxyamines R-O-N ⁇ . In this way, one obtains in a quasi quantitative manner oligomers of difunctional telechelic 1,3-diene of general formula:
• the amine H-N ⁇ obtained can be reoxidized to nitroxide and thus can be used again as a stable free radical.
• the said oligomer of formula (I) is brought as such, or alternatively in solution in an inert solvent, at a temperature at least equal to
• nitroxide is released quantitatively with a purity greater than 80% and a oligomer of telechelic 1,3-diene of formula:
• I is the residue of the initiator (-OH, for example, in the case where the initiator is hydrogen peroxide), X a residue of the initiator or a disproportionation reaction; m represents the new number-average polymerization degree and is between 1 and 1000.
• the oligomers of formula (III) generally have number average molecular weights Mn greater than the oligomers of formula (II) obtained by reduction of alkoxyamines. They also exhibit superior polymolecularity.
• the nitroxide can be easily recovered in particular by sublimation or distillation in the case where the heat treatment is carried out without solvent or alternatively by extraction using a selective solvent when the heat treatment is carried out in a solvent medium.
• the telechelic 1,3-diene oligomers of formula (I) can be advantageously used for the preparation of di- or multiblock copolymers.
• a block of formula (I) with a polymerizable monomer B such as styrene, ⁇ methylstyrene, parachloromethyl-styrene, vinyltoluene or a different 1,3-diene and carry out the polymerization of said monomer in the presence of the oligomer of formula (I) and obtain a block copolymer of formula:
• a polymerizable monomer B such as styrene, ⁇ methylstyrene, parachloromethyl-styrene, vinyltoluene or a different 1,3-diene
• block copolymers are preferably carried out in bulk, by heating the oligomer of formula (I) with the polymerizable monomer B at a temperature at least equal to 100 ° C and preferably between 1 10 ° C and 150 ° C, preferably under an inert atmosphere. It can operate at atmospheric pressure or under pressure.
• the polymerization parameters such as the oligomer block concentration of formula (I), the temperature and the polymerization time make it possible to adjust the length of block B and the degree of polymerization p.
• the polymolecularity index Ip is the ratio of the average molecular weight by weight Mw to the average molecular weight by number Mn which have been determined by gel permeation chromatography (GPC).
• the standard is polystyrene brought back in polybutadiene equivalent.
• the frequency for the proton is equal to 250 MHz
• TEMPO TEMPO
• 33.7 g (or 0.56 mole) of isopropanol 33.7 g (or 0.56 mole) of isopropanol.
• the reactor is closed and then purged with nitrogen for 15 minutes. Then introduced into the reactor 54 g (or 1 mole) of butadiene at -40 ° C.
• the reaction medium is heated to 130 ° C. and then kept for 4 hours at this temperature. During this time, the pressure goes from 26 bars to 19 bars.
• the reaction medium is cooled to room temperature and then degassed.
• the reaction crude is decanted in 24 hours.
• the densest organic phase is recovered and then evaporated under reduced pressure at 40 ° C in a rotary evaporator then under a pressure of 0.01 bar at approximately 25 ° C.
• IQH 0'61 meq / g which corresponds to an average functionality in hydroxyl functions of 1.03 calculated from Mn obtained by
• the filtrate is concentrated under reduced pressure to constant weight.
• the reactor is closed and then purged with nitrogen for 15 minutes.
• reaction medium is cooled to room temperature and then degassed.
• the reaction crude is decanted in 24 hours.
• the densest organic phase is recovered and then evaporated under reduced pressure at 40 ° C in a rotary evaporator then under a pressure of 0.01 bar at about 25 ° C.
• 35 g of a 1,3-butadiene dihydroxy-telechelic oligomer which has the following physicochemical characteristics are obtained:
• AIBN azobisisobutyronitrile
• the reaction medium is heated to 130 ° C. and then kept at this temperature for 4 hours.
• the pressure remains constant at 27 bars during this period.
• the reaction medium is cooled to room temperature and then degassed.
• reaction crude is evaporated under reduced pressure at 40 ° C in a rotary evaporator, then under a reduced pressure of 0.01 bar at about 25 ° C.
• Example 5 The product of Example 5 is subjected to a reduction by zinc in an acetic acid medium according to the operating conditions of Example 2. An oligomer of 1,3-butadiene cyanohydroxytelecommunicationchéique is obtained. Analysis by proton NMR indicates the disappearance of the piperidinyl cycle and the integration makes it possible to attribute to the oligomer the following formula:
• the reactor is closed and then purged with nitrogen for 15 minutes.
• the medium is heated to 130 ° C. and then kept at this temperature for 1 h 30 min.
• the pressure remains constant at 27 bars during this period.
• the reaction medium is cooled to room temperature and then degassed.
• reaction crude is evaporated under reduced pressure at 40 ° C in a rotary evaporator, then under a reduced pressure of 0.01 bar at about 25 ° C.
• reaction medium Purge with nitrogen. The reaction medium is heated to 130 ° C. and then maintained for
• reaction medium is poured into 500 ml of methanol.
• the mass and molar percentages are as follows: - molar percentage of butadiene: 31.5%. - mass percentage of butadiene: 1 9.3%. or the composition of the block copolymer: Mn of the polybutadiene block: 1,700 Mn of the polystyrene block: 7,100.
• This block copolymer can be represented by the formula below:
• oligomers were polycondensed with methylene diisocyanate (hereinafter designated by MDI) using a molar ratio of -NCO functions over -OH functions equal to 1.05.
• MDI methylene diisocyanate
• Table 2 The characteristics of the various starting oligomers as well as the quantities of MDI used for each test are shown in Table 2.
• - Mn is the average mass in number determined by GPC
• - IOH is the hydroxyl number expressed in meq / g determined by acetylation.
• the oligomer is degassed at 80 ° C under a reduced pressure equal to 10 mbar for 1 hour. Then it is brought back to 50 ° C.
• the required mass of MDI is then loaded at once as mentioned in table 2.
• the MDI has been previously heated to approximately 50 ° C., as is the container which is used for weighing (the melting point of the MDI being around 45 ° C).
• the reaction medium is stirred under reduced pressure for 4 to 5 minutes, so as to obtain a homogeneous mixture free of bubbles.
• the reactor is opened and the mixture is poured into a stainless steel mold, of dimensions 100 ⁇ 100 ⁇ 2 mm previously coated with a release agent.
• the product is left for 24 hours at room temperature, then treated for 24 hours at 80 ° C in a ventilated oven and then 48 hours at room temperature before cutting out standard dumbbells with a punch, on which we have measured the elongation at break ⁇ (expressed in%) and the stress at break ⁇ (expressed in MPa) according to standard ISO 527: 1 993
• This insoluble level was obtained according to the following operating protocol: Approximately 1 g of polyurethane taken from a plate, synthesized as described above, and 100 ml of

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