BLOCK COPOLYMERS THAT CAN BE USED AS PLASTICISERS

Abstract

Disclosed is a block copolymer including: at least one block A not including any phosphonate group, and including at least one poly(alkylene oxide) group and at least one block B obtained by polymerization of a monomer B1 or of a mixture of monomers with ethylenic unsaturation including at least one monomer B1, wherein a monomer B1 is a monomer with ethylenic unsaturation including at least one phosphonate function,
to its preparation method by RAFT controlled radical polymerization and to its uses.

Claims

1-22 (canceled)

23. A method for preparing a block copolymer comprising: at least one block A not comprising any phosphonate group, and comprising at least one poly (alkylene oxide) group, and at least one block B obtained by polymerization of a monomer B1 or of a mixture of monomers with ethylenic unsaturation comprising at least one monomer B1, wherein a monomer B1 is a monomer with ethylenic unsaturation comprising at least one phosphonate function comprising the steps of: b) providing a compound of the following formula (V): ##STR00019## wherein: block A is a block A not comprising any phosphonate group, and comprising at least one poly (alkylene oxide) group, L is absent or is a binding group connecting covalently the block A and the group —S—(CS)R.sub.10, R.sub.10 represents an alkyl, an arylalkyl, an aryl, an alkylaryl or a group OR.sub.11, NR.sub.12R.sub.13 or SR.sub.14, R.sub.11, R.sub.12, R.sub.13 and R.sub.14 represent independently an alkyl or an alkenyl, an arylalkyl, an aryl, an alkylaryl, wherein R.sub.12 and R.sub.13 may be connected together in order to form a ring with the nitrogen atom bearing them, c) controlled radical polymerization, or several successive controlled radical polymerizations, comprising the putting into contact: of the compound of formula (V), of a monomer B1 or a mixture of monomers with ethylenic unsaturation comprising at least one monomer B1, wherein a monomer B1 is a monomer with ethylenic unsaturation comprising at least one phosphonate function, and of a source of free radicals.

24. A method for preparing a block copolymer comprising: at least one block A not comprising any phosphonate group, and comprising at least one poly (alkylene oxide) group, and at least one block B obtained by polymerization of a monomer B1 or of a mixture of monomers with ethylenic unsaturation comprising at least one monomer B1, wherein a monomer B1 is a monomer with ethylenic unsaturation comprising at least one phosphonate function, comprising the steps of: b′) providing a compound of the following formula (V′): ##STR00020## wherein: block B is a block obtained by polymerization of a monomer B1 or of a mixture of monomers with ethylenic unsaturation comprising at least one monomer B1, wherein a monomer B1 is a monomer with ethylenic unsaturation comprising at least one phosphonate function, L′ is absent or is a binding group connecting covalently block B and the group —S—(CS)R′.sub.10, R′.sub.10 represents an alkyl, an arylalkyl, an aryl, an alkylaryl, a group OR′.sub.11, NR′.sub.12R′.sub.13 or SR′.sub.14, R′.sub.11, R′.sub.12, R′.sub.13 and R′.sub.14 represent independently an alkyl or an alkenyl, an arylalkyl, an aryl, an alkylaryl, wherein R′.sub.12 and R′.sub.13 may be bound together in order to form a ring with the nitrogen atom bearing them, c′) a controlled radical polymerization, or several successive controlled radical polymerizations, comprising the putting into contact: of the compound of formula (V′), of a monomer A1 or of a mixture of monomers with ethylenic unsaturation comprising at least one monomer A1, wherein a monomer A1 is a monomer with ethylenic unsaturation comprising at least one poly (alkylene oxide) group, and of a source of free radicals.

25. The preparation method according to claim 23, wherein the monomer B1 has the following formula (IV): ##STR00021## wherein: Y represents: a linear or branched alkyl having from 1 to 6 carbon atoms, a group —W—(CH.sub.2).sub.z—P(═O) (OR.sub.1) (OR.sub.2), or a group (CH.sub.2).sub.x—R.sub.25, wherein x represents an integer comprised between 0 and 4 and R.sub.25 represents a hydrogen atom, a phenyl or a group —CN or—CO.sub.2R.sub.9, z represents an integer comprised between 0 and 4, W represents a simple bond or a group —COO— or —CONH—, wherein when z represents 0, W represents a simple bond, R.sub.1, R.sub.2 and R.sub.9 represent independently H, a phenyl or a linear or branched alkyl having from 1 to 6 carbon atoms and optionally substituted with one or several halogens.

26. The preparation method according to claim 25, wherein W represents a simple bond and z represents 0.

27. The preparation method according to claim 26, wherein the monomer B1 is vinyl phosphonic acid.

28. The preparation method according to claim 23, wherein, during step c) or b′), the mixture of monomers with ethylenic unsaturation comprising at least one monomer B1 comprises: at least one monomer B1 with ethylenic unsaturation comprising at least one phosphonate function, and at least one monomer B2 selected from acrylic acid, methacrylic acid, a monomer with ethylenic unsaturation comprising an aminomethylene bisphosphonic or gem-bisphosphonic function or a monomer with ethylenic unsaturation comprising a sulfonic or sulfonate function.

29. The preparation method according to claim 23, wherein the block copolymer comprises a block A consisting in a poly (alkylene oxide), the method comprising, prior to step b), a step a) for preparing a compound of formula (V) comprising the steps of: a3) providing a poly(alkylene oxide), a4) grafting at one end of said poly(alkylene oxide) a group of formula —S(C═S)R.sub.10.

30. The preparation method according to claim 23, comprising, after step c) or c′), an oxidation step d).

31. A block copolymer which may be obtained by the method according to claim 23.

32. A block copolymer comprising: at least one block A not comprising any phosphonate group, and comprising at least one poly(alkylene oxide) group and at least one block B obtained by polymerization of a monomer B1 or of a mixture of monomers with ethylenic unsaturation comprising at least 30% by weight of a monomer B1, wherein a monomer B1 is a monomer with ethylenic unsaturation comprising at least one phosphonate function.

33. The block copolymer according to claim 31, wherein, in each block A, each poly(alkylene oxide) group has independently the following formula (I):
R.sub.3—(O—R.sub.4).sub.n—  (I) wherein: R.sub.3 is a hydrogen atom or a monovalent hydrocarbon group including 1 à 12 carbon atoms and optionally one or several heteroatoms, n represents an integer from 2 to 500, each R.sub.4 represents independently a branched or linear alkylene group comprising from 2 to 6 carbon atoms.

34. The block copolymer according to claim 33, wherein, in each block A, each R.sub.4 represents independently a group —CH.sub.2—CH.sub.2—, —CHCH.sub.3—CH.sub.2—, —CH.sub.2—CHCH.sub.3— or —CH.sub.2—CH.sub.2—CH.sub.2—

35. The block copolymer according claim 31 wherein the block A is obtained by polymerization of a monomer A1 or of a mixture of monomers with ethylenic unsaturation comprising at least one monomer A1, wherein a monomer A1 is a monomer with ethylenic unsaturation and comprising at least one poly(alkylene oxide) group.

36. The block copolymer according to claim 35, wherein the monomer A1 has the following formula (II): ##STR00022## wherein: R.sub.3 is a hydrogen atom or a monovalent hydrocarbon group including 1 à 12 carbon atoms and optionally one or several heteroatoms, n represents an integer from 2 to 500, each R.sub.4 represents independently a branched or linear alkylene group comprising from 2 to 6 carbon atoms, R.sub.5 represents —CH.sub.2—, —O— or —NR.sub.8— wherein R.sub.8 represents H or a branched or linear alkyl group comprising from 1 to 6 carbon atoms, R.sub.6 is absent or represents —(C═O)— or —(CH.sub.2).sub.q—, wherein q represents 1, 2 or 3, R.sub.7 represents H or Me, and R.sub.17 and R.sub.18 represent independently H or Me.

37. The block copolymer according to claim 31, wherein each block A of the block copolymer is obtained by polymerization of a mixture of monomers comprising less than 10% by weight of monomers comprising an ionic group.

38. The block copolymer according to claim 31, wherein the block A of the block of the copolymer according to the invention consists in a poly(alkylene oxide).

39. The block copolymer according to claim 31, wherein the block B has a degree of polymerization from 2 to 50.

40. The block copolymer according to claim 31 having an weight-average molecular weight from 450 to 100,000 g/mol.

41. Dispersant agent of mineral particles, plasticizer for suspensions of mineral particles, adhesion promoter, anticorrosion agent, flame retardant, stabilizer during milling of mineral particles, or anti-scale agent comprising the block copolymer according to claim 31.

Description

[0238] The figures and examples below illustrate the invention.

[0239] FIG. 1 illustrates the time-dependent change in the amount of polymer adsorbed on cement particles (in mg/g) versus the concentration of free polymer in mg/L for a polymer CHRYSO® Fluid Optima100 (comparative—rhombuses), HD2 (triangles), HD3 (squares) and SM02 (circles). The arrow shows the increase in the number of PO.sub.3.sup.2−functions.

EXAMPLE 1

Synthesis of a POE—b—PVPA (Polyvinyl Phosphonic Acid) Copolymer.

[0240] In this example, the copolymer is a diblock polymer with: a block A of formula

##STR00012##

a block B obtained by homopolymerization of vinyl phosphonic acid, the blocks A and B being bound through a junction units of formula —(C═O)—CHME—

[0241] 1.1. Preparation of the Transfer Agents of Formula

##STR00013##

(a compound fitting formula (V)) (steps a3) and a4) of the method according to the invention).

[0242] The ω—hydroxy end of the poly(ethylene oxide) was modified by a xanthate group (2-bromopropionate bromide). The synthesis was carried out from a commercial methoxypolyethylene glycol homopolymer of molar mass 2012 g.mole.sup.−1 (DP=45) in dichloromethane at room temperature (20° C.) for 12 h in the presence of triethylamine. In a first phase, it is reacted with the dibrominated compound of the following formula

##STR00014##

in order to obtain a polymer terminated by a halogen functionality instead of the hydroxyl function, as illustrated in the scheme 1 below.

##STR00015##

[0243] In a second step, the xanthate functionality is introduced according to the reaction of scheme 2.

##STR00016##

[0244] .sup.1H NMR spectroscopic analysis 400 MHz confirm the disappearance of the hydroxyl terminal group of the poly(ethylene oxide) and the appearance of a xanthate group.

[0245] The product appears after purification as a powder of beige color. The total yield of the synthesis was close to 80%. The .sup.1H NMR analysis confirm that all the poly-ethyleneglycol polymers were terminated by the RAFT functionality. This polymer was then used as a macro-RAFT agent for polymerizing vinylphosphonic acid.

[0246] 1.2. Polymerization of Vinylphosphonic Acid (Step c))

[0247] The polymerization of vinylphosphonic acid (VPA) was initiated with AIBA [V50 =2,2′-azo-bis-(2-amidinopropane) hydrochloride of the following formula:

##STR00017##

[0248] at 65° C. in water in the presence of the POE-xanthate block (FIG. 12).

[0249] The analysis of the reaction crude material with .sup.31P showed that residual VPA remained in a non-negligible amount. The operating conditions were optimized for minimizing the residual vinylphosphonic acid level.

[0250] Three tests were carried out by using the transfer agent prepared in 1.1. as a macro-RAFT agent. The polymerization of the VPA was carried out at 65° C. in water. The conversion attains the limit of 58% after 24 h. The product was purified by ultrafiltration, in order to for result in a copolymer having less than 2% of residual vinylphosphonic acid monomer.

[0251] The .sup.1H and .sup.31P NMR spectroscopic analyses confirm the obtaining of a polyvinylphosphonic acid block with degrees of polymerization DP of respectively 4 (SMO2-block copolymer 1), of 5 (HD2-block copolymer 2) and of 12 (HD3-block copolymer 5).

##STR00018##

[0252] The obtained diblock copolymers were then formulated by adding 0.5% by weight of oleic amine to 2 moles of ethylene oxide (marketed under the name of NORAMOX O.sub.2 by CECA) and of 1.2% by weight of tributylphosphate (antifoam agent).

[0253] Finally, the products were diluted with water in order to obtain a 20% dry extract, and then neutralized with sodium hydroxide at pH 7. The thereby prepared dispersants are ready-to-use.

EXAMPLE 2

Determination of the Adsorption Isotherms of Diblock Copolymers of Example 1 at the Surface of the Cement Particles.

[0254] The diblock polymers of Example 1 were tested with an approach which combines a rheology study for 2 hours with measurements of adsorption of the molecules on the cement particles.

[0255] The rheometer Kinexus (Malvern Instruments, UK) was programed for conducting measurements of the stress versus the shear gradient (flow curves) after destructuration of the cement slurry at 5′, 60′ and 120′. Between two measurements of the flow curve, the apparatus performed a creep curve, i.e. recorded the time-dependent change of the viscosity, therefore the tendency to structuration given by hydration of the cement, under a constant stress of 4 Pa. In synchronization with the flow curves, about 5 ml of cement juice were extracted by centrifugation of the slurry (2 mins at 5,000 rpm) and filtered (0.2 pm Nylon) in order to obtain a clean solution.

[0256] The solutions were diluted and analyzed by measurement of Total Organic Carbon (TOC) for detecting the amount of polymer which remains in the interstitial liquid. The difference in the values of TOC before and after contact with the cement gives the amount of adsorbed polymer.

[0257] The cement slurry was prepared with a Krups kneader according to the proportions reported in table 1.

TABLE-US-00001 TABLE 1 Composition of the slurry (g ± 0.02) CEM I 52.2N Sand Le Havre Filler Erbray Water Sand 0/0.160 mm 0/0.315 mm 254.55 145.45 167.35 36.15 163.85

[0258] The diblock molecules were dosed between 0.8% and 2% over the mass of the total binder (cement+filler). These different dosages gave the possibility of plotting the values of adsorbed polymer versus the free polymer concentration, therefore for obtaining an adsorption isotherm.

[0259] The curves obtained in FIG. 1 correspond to the adsorption isotherms of the polymers on the cement particles. They very clearly show that HD3, with 12 units of vinylphosphonic acid, has a greater affinity for the cement grains than HD2 and SM02 which only respectively have 5 and 4 phosphonic acid units. CHRYSO® Fluid Optima 100 is the less adsorbed polymer.

EXAMPLE 3

Use of the Diblock Copolymers of Example 1 in a Formulation of a Cement Slurry.

[0260] Composition of the Evaluation Formulation

[0261] The diblock copolymers of Example 1 were evaluated according to the following formulation:

TABLE-US-00002 CEM I 52.5 N Le Havre 624.9 g ERBRAY lime stone filler 412.1 g FULCHIRON (sand) 587.7 g Standardized sand AFNOR 1,350 g Total water 375.1 g

[0262] The copolymer level is expressed in % based on the total binder (filler+cement=1,037 g).

[0263] Operating Procedure for Preparing the Mortar

[0264] The mortar was prepared according to the following procedure: two sands, standardized and FULCHIRON sand were introduced into the bowl of the kneader PERRIER. After kneading the sands for 30 seconds at a rate of about 140 rpm, within 15 seconds, we added the pre-wetting water which represented ⅓ of the total water to be introduced. The mixture was continued for 15 seconds before leaving at rest the mass for 4 minutes. Next, the cement and the lime stone filler (origin ERBRAY provided by MEAC) were introduced and then the mixing was continued for 1 minute before adding the remainder of the mixing water as well as the totality of the adjuvant within 30 seconds. The kneader was then stopped for a few instants so as to scrape the edges of the kneading bowl in order to have a quite homogeneous mass and then mixing was continued for a further 1 minute at a rapid rate of 280 rpm.

[0265] Evaluation Criterion

[0266] The evaluation of the application properties of the block copolymers was carried out by means of rheological measurements. Thus the workability of the hydraulic compositions formulated in the presence of these diblock copolymers was estimated by measuring the slump flow diameter (slump flow-diameter of the pool formed after flowing). The spreading was measured after 5, 30, 60, 90 and 120 mins along 2 diameters at 90° . The tests were conducted at 20° C.

[0267] Results

[0268] The spreading-out measurements of the cement slurries are shown in table 2.

TABLE-US-00003 TABLE 2 Spreading out of the mortar depending versus the adjuvant. Adjuvant Optima 100 (reference) HD2 Dosage (%) 1.10 1.10 Spread after 5 mins 290 410

[0269] Upon examining table 2, it is noticed that the diblock copolymer poly(ethylene oxide—b-polyvinylphosphonic acid) HD2 has, for equal dosage, a fluidifying power much greater than that of the control Optima 100.