Patent Application
20060160940
The instant invention relates to a process for manufacturing nanoparticles by intercalating and/or exfoliating natural or synthetic clays using block or comb copolymers having one cationic block and at least one non polar block, which are prepared by controlled free radical polymerization (CFRP). The invention also relates to improved nanocomposite compositions containing nanoparticles produced by this process and to the use of these nanocomposite compositions as, for example, in coatings, sealants, caulks, adhesives and as plastic additives.
One way of improving polymer properties is by adding a natural or synthetic clay material to polymers to form composite materials. However, incorporating clays into polymers may got provide a desirable improvement in the physical properties, particularly mechanical and optical properties of the polymer may be adversely affected.
Nanonocomposite compositions containing finely dispersed natural or synthetic clay with at least partially intercalated and/or exfoliated layers and mixtures of ethylenically unsaturated monomers and/or polymers therefrom have therefore attracted much interest in the last years. These materials combine the desired effects of dispersed clay by avoiding the negative influence on, for example, the mechanical or optical properties.
Such compositions, methods for making them and their use in polymers and coatings are for example described in WO 02/24759. Polymerization processes are described using montmorillonite clay, acrylate monomers and for example ammonium persulfate as radical initiator. This conventional polymerization process leads to polymers with broad molecular weight distributions and a high polydispersity index (PD).
Another approach is, for example described by Yang et al. in Mat. Res. Soc. Symp. Proc. Vol. 703, 2002, pages 547-552. Di- or triblock copolymers are prepared containing dimethyl-aminoethyl methacrylate as monomer in one block and, for example, methacrylic acid as monomer in the other block. From these copolymers cationic blocks are obtained by protonating the aminoblock in the copolymer. The protonated blockcopolymers are then used for intercalating montmorillonite. The D-spading between the layers is typically between 1.5 and 2 nm. There is nothing disclosed, as to how the preparation of the block copolymers is carried out, in particular, the polydispersity index MW/Mn of the individual blocks and of the total block copolymer is not known.
The instant invention provides improved nanoparticles of natural and synthetic clay, having in general higher D-spacings. The nanoparticles are prepared by intercalating and/or exfoliating natural or synthetic clays using block or comb copolymers having one cationic block and at least one non polar block, which copolymers are prepared by controlled free radical polymerization (CFRP).
Controlled free radical polymerization per se is known and can be carried out by using for example atom transfer radical polymerization (ATRP) as described in WO 96/30421. WO 96/30421 discloses a controlled or “living” polymerization process of ethylenically unsaturated monomers such as styrene or (meth)acrylates by employing the ATRP method. According to this method initiators are employed which generate a radical atom such as .Cl, in the presence of a redox system of transition metals of different oxidation states, e.g. Cu(I) and Cu(II), providing “living” or controlled radical polymerization.
Another further suitable polymerization process is disclosed in U.S. Pat. No. 4,581,429. U.S. Pat. No. 4,581,429 discloses a free radical polymerization process by controlled or “living” growth of polymer chains which produces defined oligomeric homopolymers and copolymers, including block and graft copolymers. Disclosed is the use of initiators of the partial formula R′R″N—O—X. In the polymerization process the free radical species R′R″N—O. and .X are generated. .X is a free radical group, e.g. a tert.-butyl or cyanoisopropyl radical, capable of polymerizing monomer units containing ethylene groups.
A variation of the above process s disclosed in U.S. Pat. No. 5,322,912 wherein the combined use of a free radical initiator and a stable free radical agent of the basic structure R′R″N—O. for the synthesis of homopolymers and block copolymers is described.
All three processes are useful for the preparation of blocker comb copolymers wherein the block copolymers have a narrow molecular weight distribution and hence a low polydispersity index.
Surprisingly it has been found, that clay nanoparticles prepared from block- or comb copolymers obtained by CFRP are not only intercalated but in many cases exfoliated and therefore dispersions containing these nanoparticles are much more storage stable. In most cases there is no agglomeration or aggregation even after long storage periods. The nanocomposite compositions of the instant invention can be optically almost transparent, indicating the fine distribution, on the nanometer scale, of the clay.
One aspect of the invention is a process for preparing a block- or comb polymer, clay nanocomposite dispersion comprising
If the clay material is a synthetic one, it may be produced by gas-phase or sol-gel processes, for example Optigel® from Süd Chemie.
Natural clay minerals are typically comprised of hydrated aluminum silicates that are fine-grained and have a platy habit. The crystalline structure of a typical clay mineral is a multi-layered structure comprised of combinations of layers of SiO4 tetrahedra that are joined to layers of AlO(OH)2 octahedra. A so called “gallery” is formed which describes the defined interlayer spaces of the layered clay minerals. Depending of the clay mineral the gallery may contain water and/or other constituents such as potassium, sodium or calcium cations. Clay minerals vary, based upon the combination of their constituent layers and cations. Isomorphic substitution of the cations of clay mineral, such as Al3+ or Fe3+ substituting for the Si4+ ions in the tetrahedral network, or Al3+, Mg2+ or Fe2+ substituting for other cations in the octahedral network, typically occurs and may impart a net negative charge on the clay structure. Natural occurring elements within the gallery of the clay, such as water molecules or sodium or potassium cations, are attracted to the surface of the clay layers due to this net charge.
Nanocomposites are compositions in which at least one of its constituents has one or more dimensions, such as length, width or thickness in the nanometer size range. The term nanocomposite, as used herein, denotes the state of matter wherein intercalated and at least partially exfoliated clay layers are surrounded by a polymer matrix.
The term “intercalated nanocomposite”, as used herein describes a nanocomposite that contains a regular insertion between the clay layers.
The term “exfoliated nanocomposite” as used herein describes a nanocomposite wherein the a few nm thick layers of clay with polymer molecules attached to K are dispersed in the matrix (oligomer/polymer) forming a composite structure on the nano/micro scale.
The clay minerals are items of commerce and are for example supplied by Süd-Chemie Inc., Germany or Nanocore, USA.
The natural or synthetic clay is for example a phyllosilicate.
In particular the natural clay is selected from the group consisting of smectite, montmorillonite, saponite, beidellite, mica, sauconite, ledikite, montronite, hectorite, stevensite, vermiculite, kaolinite, hallosite and combinations thereof.
Special preference is given to montmorillonite.
As already mentioned it is indispensable that the block copolymers are prepared by controlled free radical polymerization (CFRP). There are essentially three suitable routes:
a1) polymerization in the presence of alkoxyamine initiator/regulator compounds;
a2) polymerization in the presence of a stable nitroxyl free radical and a radical initiator (source of free radicals) and
a3) polymerization under atom transfer radical polymerization (ATRP) conditions. All three routes are known and widely described.
For example the structural element
may be part of a cyclic ring system or substituted to form a acyclic structure.
Suitable nitroxylethers and nitroxyl radicals are principally known from U.S. Pat. No. 4,581,429 or EP-A-621 878. Particularly useful are the open chain compounds described in WO O8/13392, WO 99/03894 and WO 00/07981, the piperidine derivatives described in WO 99/67298 and GB 2335190 or the heterocyclic compounds described in GB 2342649 and WO 96/24620. Further suitable nitroxylethers and nitroxyl radicals are described in WO 02/4805 and in WO 021100831.
Stable free radicals having a structural element
are for example disclosed in EP-A-621 878.
are for example given in WO 96/24620.
Preferably the structural element
is a structural element of formula (I)
G1, G2, G3, G4 are independently C1-C6alkyl or G1 and G2 or G3 and G4, or G1 and G2 and G3 and G4 together form a C5-C12cycloalkyl group;
G5, G6 independently are H, C1-C18alkyl, phenyl, naphthyl or a group COOC1-C18alkyl.
In particular the structural element of formula (I) is of formula A, B or O,
wherein
m is t,
R is hydrogen, C1-C18alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an α,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
p is 1;
R101 is C1-C12alkyl, C5-C7cycloalkyl, C7-C8aralkyl, C2-C18alkanoyl, C3-C5alkenoyl or benzoyl;
R102 is C1-C18alkyl, C5-C7cycloalkyl, C2-C8alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula —CH2CH(OH)-Z or of the formula —CO-Z or —CONH-Z wherein Z is hydrogen, methyl or phenyl;
G6 is hydrogen and G5 is hydrogen or C1-C4alkyl,
G1 and G3 are methyl and G2 and G4 are ethyl or propyl or G1 and G2 are methyl and G3 and G4 are ethyl or propyl; and
X is selected from the group consisting of
—CH2-phenyl, CH3CH-phenyl, (CH3)2C-phenyl, (C6-C9cycloalkyl)2CCN, (CH3)2CCN,
—CH2CH═CH2, CH3CH—CH=CH2 (C1-C4alkyl)CR20—C(O)— phenyl, (C1-C4)alkyl-CR20—C(O)—(C1-C4)alkyl, (C1-C4)alkyl-CR20—C(O)—(C1-C4)alkyl, (C1-C4)alkyl-CR20—C(O—N-di(C1-C4)alkyl, (C1-C4)alkyl-CR20—C(O)—NH(C1-C4)alkyl, (C1-C4)alkyl-CR20-C(O)—NH2, wherein
R20 is hydrogen or (C1-C4)alkyl.
The above compounds and their preparation are described in GB 2335190 and GB 2 361 235.
Another preferred group of nitroxylethers of step al) are those of formula (Ic), (Id), (Ie), (If)i (Ig) or (Ih)
wherein R201, R202, RR203 and R204 independently of each other are C1-C18alkyl, C3-C18alkenyl, C3-C18alkinyl, C1-C18alkyl, C3-C18alkenyl, C3-C18alkinyl which are substituted by OH, halogen or a group —O—C(O)—R205, C2-C18alkyl which is interrupted by at least one O atom and/or NR205 group, C3-C12cycloalkyl or C5-C10aryl or R201 and R202 and/or R203 and R204 together with the linking carbon atom from a C3-C12cycloalkyl radical;
R205, R206 and R207 independently are hydrogen, C1-C18alkyl or C6-C10aryl;
R203 is hydrogen, OH, C1-C18alkyl, C3-C18alkenyl, C3-C18alkinyl, C1-C18alkyl, C3-C18alkenyl, C3-C18alkinyl which are substituted by one or more OH, halogen or a group —O—C(O)—R205, C2-C18alkyl which is interrupted by at least one O atom and/or NR206 group, C3-C12cycloalkyl or C6-C10aryl, C7-C8phenylalkyl, C6-C10heteroaryl, —C(O)—C1-C18alkyl, —O—C1-C18alkyl or —COOC1-C18alkyl;
R209, R210, R211 and R212 are independently hydrogen, phenyl or C1-C18alkyl; and
X is selected from the group consisting of —CH2-phenyl, CH3CH-phenyl, (CH3)2C-phenyl, (C5-C6cycloalkyl)2CCN, (CH3)2CNN,
—CH2CH═CH2, CH3CH—CH═CH2(C1-C4alkyl)CR20-C(O)-phenyl, (C1-C4)alkyl-CR20—C(O)—(C1-C4)alkoxy, (C1-C4)alkyl-CR20—C(O)—(C1-C4)alkyl, (C1-C4)alkyl-CR20—C(O)—N-di(C1-C4)alkyl, (C1-C4)alkyl, (C1-C4)alkyl-CR20—C(O)—NH(C1-C4)alkyl, (C1-C4)alkyl-CR20—C(O)—NH2, wherein
R20 is hydrogen or (C1-C4)alkyl.
More preferably in formula (Ic), (Id), (Ie), (f), (Ig), and (Ih) at least two of R201, R202, R203 and R204 are ethyl, propyl or butyl and the remaining are methyl; or
R201 and R202 or R203 and R204 together with the linking carbon atom from a C5-C6cycloalkyl radical and one of the remaining substituents is ethyl, propyl or butyl.
Most preferably X is CH3CH-phenyl.
The above compounds and their preparation is described in GB 2342649.
Further suitable compounds are the 4-imino compounds of formula (II)
G11, G12, G13 and G14 are independently C1-C4alkyl or G11 and G12 together and G13 and G14 together, or G11 and G12 together or G13 and G14 together are pentamethylene;
G15 and G16 are each independently of the other hydrogen or C1-C4alkyl;
X is as defined above;
It is 1, 2, 3, or 4
Y is O, NR302 or when n is 1 and R301 represents alkyl or aryl Y is additionally a direct bond;
R302 is H, C1-C18alkyl or phenyl;
if k is 1
R301 is H, straight or branched C1-C18alkyl, C3-C18alkenyl or C3-C18alkinyl, which may be unsubstituted or substituted, by one or more OH, C1-C8alkoxy, carboxy, C1-C8alkoxycarbonyl;
C6-C12cycloalkyl or C5-C12cycloalkenyl;
phenyl, C7-C9phenylalkyl or naphthyl which may be unsubstituted or substituted by one or more C1-C8alkyl, halogen, OH, C1-C8alkoxy, carboxy, C1-C8alkoxycarbonyl;
—C(O)C—C1-C18alkyl, or an acyl moiety of a c,unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
—SO3−Q+, —PO(OR2)2, —P(O)(OR2)2—SO2—R2, —CO—NH—R2, —CONH2, COOR2, or Si(Me)3, wherein Q+ is H+, ammonium or an alkali metal cation;
if k is 2
R301 is C1-C18alkylene, C3-C18alkenylene or C3-C18alkinylene, which may be unsubstituted or substituted, by one or more OH, C1-C8alkoxy, carboxy, C1-C8alkoxycarbonyl;
or xylylene; or
R301 is a bisacyl radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms, or a cycloaliphatic or aromatic dicarboxylic acid having 8-14 carbon atoms;
if k is 3,
R301 is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid; and
if k is 4, R301 is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid.
Preferably G15 is hydrogen and G16 is hydrogen or C1-C4alkyl, in particular methyl, and G11 and G13 are methyl and G12 and G14 are ethyl or propyl or G11 and G12 are methyl and G13 and G14 are ethyl or propyl.
The 4 imino compounds of formula V can be prepared for example according to E. G. Rozantsev, A. V. Chudinov, V. D. Sholle. :lzv. Aked. Nauk. SSSR, Ber. Khim. (9), 2114 (1980), starting from the corresponding 4-oxonitroxide in a condensation reaction with hydroxylamine and subsequent reaction of the OH group. The compounds are described WO 021100831.
When the polymerization process is carried out according to route a2) the structural element
is for example a structural element of formula (I′)
G1, G2, G3, G4 are independently C1-C6alkyl or G1 and G2 or G3 and G4, or G1 and G2 and G3 and G4 together form a C5-C12cycloalkyl group;
G5, G6 independently are H, C1-C18alkyl, phenyl, naphthyl or a group COOC1-C18alkyl.
Preference is given to compounds wherein the structural element of formula (I′) is of formula A′, B′ or O′,
wherein
m is 1,
R is hydrogen, C1-C18alkyl which is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an α,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
p is 1;
R101 is C1-C12alkyl, C6-C7cycloalkyl, C7-C8aralkyl, C2-C18alkanoyl, C3-C6alkenoyl or benzoyl;
R102 is C1-C18alkyl, C5-C7cycloalkyl, C2-C8alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, or is glycidyl, a group of the formula —CH2CH(OH)-Z or of the formula —CO-Z or —CONH-Z wherein Z is hydrogen, methyl or phenyl;
G6 is hydrogen and G5 is hydrogen or C1-C6alkyl,
G1 and G3 are methyl and G2 and G4 are ethyl or propyl or G1 and G2 are methyl and G3 and G4 are ethyl or propyl.
Also suitable are the compounds wherein the structural element
is of formula (II′)
G11, G12, G13 and G14 are independently C1-C4alkyl or G11 and G12 together and G13 and G14 together, or G11 and G12 together or G13 and G14 together are pentamethylene;
G15 and G16 are each independently of the other hydrogen or C1-C4alkyl;
k is 1, 2, 3, or 4
Y is 0, NR302 or when n is 1 and R301 represents alkyl or aryl Y is additionally a direct bond;
R3m is H, C1-C18alkyl or phenyl;
if k is 1
R301 is H, straight or branched C1-C18alkyl, C3-C18alkenyl or C3-C18alkinyl, which may be unsubstituted or substituted, by one or more OH, C1-C8alkoxy, carboxy, C1-C18alkoxycarbonyl;
C5-C12cycloalkyl or C5-C12cycloalkenyl;
phenyl, C7-C9phenylalkyl or naphthyl which may be unsubstituted or substituted by one or more C1-C8alkyl, halogen, OH, C1-C8alkoxy, carboxy, C1-C8alkoxycarbonyl;
—C(O)—C1-C33alkyl, or an acyl moiety of a α,β-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
—SO3−Q+, —PO(O−Q+)2, —P(O)(OR2)2, —SO2—R2, —CO—NH—R2, —CONH2, COOR2, or Si(Me)3, wherein Q+ is H+, ammonium or an alkali metal cation;
if k is 2
R301 is C1-C18alkylene, C3-C18alkenylene or C3-C18alkenylene, which may be unsubstituted or substituted, by one or more OH, C1-C8alkoxy, carboxy, C1-C8alkoxycarbonyl;
or xylylene; or
R301 is a bisacyl radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms, or a cycloaliphatic or aromatic dicarboxylic acid having 8-14 carbon atoms;
if k is 3,
R301 is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid; and
if k is 4, R301 is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid.
The alkyl radicals in the various substituents may be linear or branched. Examples of alkyl containing 1 to 18 carbon atoms are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.
Alkenyl with 3 to 18 carbon atoms is a linear or branched radical as for example propenyl, 2-butenyl, 3-butenyl, isobutenyl, n-2,4-pentadienyl, 3-methyl-2-butenyl, n-2-octenyl, n-2-dodecenyl, iso-dodecenyl, oleyl, n-2-octadecenyl oder n-4-octadecenyl.
Preferred is alkenyl with 3 bis 12, particularly preferred with 3 to 6 carbon atoms.
Alkenyl with 3 to 18 is a linear or branched radical as for example propinyl
2-butinyl, 3-butinyl, n-2-octinyl, oder n-2-octadecinyl. Preferred is alkinyl with 3 to 12, particularly preferred with 3 to 6 carbon atoms.
Examples for hydroxy substituted alkyl are hydroxy propyl, hydroxy butyl or hydroxy hexyl.
Examples for halogen substituted alkyl are dichloropropyl, monobromobutyl or trichlorohexyl.
C2-C18alkyl interrupted by at least one O atom is for example —CH2—CH2—O—CH2—CH3, —CH2—CH2—O—CH3— or —CH2—CH2—O—CH2—CH2CH2—O—CH2—CH3—. It is preferably derived from polyethylene glycol. A general description is —(CH2)3—O)b—H/CH3, wherein a is a number from 1 to 6 and b is a number from 2 to 10.
C2-C18alkyl interrupted by at least one NR6 group may be generally described as —((CH2)a—NR5)b—H/CH3, wherein a, b and R5 are as defined above.
C3-C12cycloalkyl is typically, cyclopropyl, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl or trimethylcyclohexyl.
C6-C10 aryl is for example phenyl or naphthyl, but also comprised are C1-C4alkyl substituted: phenyl, C1-C4alkoxy substituted phenyl, hydroxy, halogen or nit substituted phenyl. Examples for alkyl substituted phenyl are ethylbenzene, toluene, xylene and its isomers, mesitylene or isopropylbenzene. Halogen substituted phenyl is for example dichlorobenzene or bromotoluene.
Alkoxy substituents are typically methoxy, ethoxy, propoxy or butoxy and their corresponding isomers.
C7-C8phenylalkyl is benzyl, phenylethyl or phenylpropyl.
C5-C10heteroaryl is for example pyrrol, pyrazol, imidazol, 2, 4, dimethylpyrrol, 1-methylpyrrol, thiophene, furane, furfural, indol, cumarone, oxazol, thiazol, isoxazol, isothiazol, triazol, pyridine, α-picoline, pyridazine, pyrazine or pyrimidine.
If R is a monovalent radical of a carboxylic add, it is, for example, an acetyl, propionyl, butyryl, valeroyl, caproyl, stearoyl, lauroyl, acryloyl, methacryloyl, benzoyl, cinnamoyl or β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl radical.
C1-C18alkanoyl is for example, formyl, propionyl, butyryl, octanoyl, dodecanoyl but preferably acetyl and C3-C5alkenoyl is in particular acryloyl. in general the polymerization processes using nitroxylethers a1) or nitroxyl radicals together with a free radical initiator a2) are preferred. In particular polymerization process a1) is very suitable.
Particularly suitable nitroxylethers and nitroxyl radicals are those of formulae
The free radical initiator of component a2) is preferably a bis-azo compound, a peroxide, perester or a hydroperoxide.
Specific preferred radical sources are 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methyl-butyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvale-ronitrile, 1,1′-azobis(1-cyclohexanecarbonitrile), 2,2′-azobis(isobutyramide)dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrue, dimethyl-2,2′-azbisisobutyrate, 2-(carbamoylazo)isobutyronitrile, 2,2′-azobis(2,4,4-timethylpentane), 2,2′-azobis(2-methylpropane), 2,2-azobis(N,N′-dimethylenelsobutyramidine), free base or hydrochloride, 2,2′-azobis(2-amidinopropane), free base or hydrochloride, 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} or 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide; acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate, t-amyl pemeodecanoate, t-butyl pemeodecanoate, t-butyl perpivalate, t-amylperpivalate, bis(2,4-dichlorobenzoyl)peroxide, diisononanoyl peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, bis(2-methylbenzoyl)peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate, bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleinate, 1,1-bis(t-butylperoxy)3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, t-butyl peroxy isopropyl carbonate, t-butyl perisononaoate, 2,5-dimethylhexane 2,5-dibenzoate, t-butyl peracetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis (t-butylperoxy) butane, 2,2 bis(t-butylperoxy)propane, dicumyl peroxide, 2,5-dimethylhexane-2,5-di-t-butylperoxide, 3-t-butylperoxy 3-phenylphthalide, di-t-amyl peroxide, α,α′-bis(t-butylperoxy isopropyl)benzene, 3,5-bis(t-butylperoxy)3,5-dimethyl 1,2-dioxolane, di-t-butyl peroxide, 2,5-dimethylhexyne-2,5-di-t-butylperoxide, 3,3,6,6,9,9-hexamethyl 1,2,4,5-tetraoxa cyclononane, p-menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene mono-α-hydroperoxide, cumene hydroperoxide or t-butyl hydroperoxide.
A suitable component a3) contains a compound of formula (III),
with a radically transferable atom or group .Hal as is described in WO 96/30421 and WO 98/01480. A preferred radically transferable atom or group .Hal is .Cl or .Br, which is cleaved as a radical from the initiator molecule.
Preferably [In] represents the polymerization initiator fragment of a polymerization initiator of formula (III),
capable of initiating polymerization of monomers or oligomers which polymerization initiator is selected from the group consisting of C1-C8-alkyl halides, C8-C15-aralkylhalides, C2-C8α-haloalkyl esters, arene sulfonyl chlorides, haloalkane-nitriles, α-haloacrylates and halolactones, and
p and q represent one.
The polymerization process in the presence of a compound of formula (III) is known as ATRP (Atom Transfer Radical Polymerization) and WO 96/30421 discloses a controlled or “living” polymerization process of ethylenically unsaturated monomers such as styrene or (meth)acrylates by employing the ATRP method. According to this method initiators are employed which generate a radical atom such as .Cl, in the presence of a redox system of transition metals of different oxidation states, e.g. Cu(I) and Cu(II), providing “living” or controlled radical polymerization.
Specific initiators are selected from the group consisting of α,α′-dichloro- or α,α′-dibromoxylene, p-toluenesulfonylchloride (PTS), hexakis-(α-chloro- or α-bromomethyl)-benzene, 2-chloro- or 2-bromopropionic acid, 2-chloro- or 2-bromolsobutyric acid, 1-phenethyl chloride or bromide, methyl or ethyl 2-chloro- or 2-bromopropionate, ethyl-2-bromo- or ethyl-2-chloroisobutyrate, chloro- or bromoacetonitrile, 2-chloro- or 2-bromopropionitrile, α-bromo-benz-acetonitrile and α-bromo-γ-butyrolactone (=2-bromo-dihydro-2(3H)furanone).
The transition metal in the oxidizable transition metal complex catalyst salt used in the process of the invention is present as an oxidizable complex ion in the lower oxidation state of a redox system. Preferred examples of such redox systems are selected from the group consisting of Group V(B), VI(B), VII(B), VIII, IB and IIB elements, such as Cu+/Cu2+, Cu0/Cu+, Fe0/Fe2+, Fe2+/Fe3+, Ru2+/Ru3+, Ru3+/Ru4+, Os2+/Os3+, Vn+/V(n+1)+, Cr2+/Cr3+, Co+/Co2+, Co2+/Co3+, Ni0/Ni+, Ni+/Ni2+, Ni2+/Ni3+, Mn0/Mn2+, Mn2+/Mn3+, Mn3+/Mn4+ or Zn+/Zn2+.
The ionic charges are counterbalanced by anionic ligands commonly known in complex chemistry of transition metals, such hydride ions (H−) or anions derived from inorganic or organic acids, examples being halides, e.g. F−, Cl−, Br− or I−, fluoro complexes of the type BF4−; PF6−, SbF6− or AsF6−, anions of oxygen acids, alcoholates or acetylides or anions of cyclopentadiene.
Anions of oxygen acids are, for example, sulfate, phosphate, perchlorate, perbromate, penodate, antimonate, arsenate, nitrate, carbonate, the anion of a C1-C8carboxylic acid, such as formate, acetate, propionate, butyrate, benzoate, phenylacetate, mono-, di- or trichloro- or -fluoroacetate, sulfonates, for example methylsulfonate, ethylsulfonate, propylsulfonate, butylsulfonate, trifluoromethylsulfonate (triflate), unsubstituted or C1.C4alkyl-, C1-C4alkoxy- or halo-, especially fluoro-, chloro- or bromo-substituted phenylsulfonate or benzylsulfonate, for example tosylate, mesylate, brosylate, p-methoxy- or p-ethoxyphenylsulfonate, pentafluorophenylsulfonate or 2,4,6-triisopropylsulfonate, phosphonates, for example methylphosphonate, ethylphosphonate, propylphosphonate, butylphosphonate, phenylphosphonate, p-methylphenylphosphonate or benzylphosphonate, carboxylates derived from a C1-C8carboxylic acid, for example formate, acetate, propionate, butyrate, benzoate, phenylacetate, mono-, di- or trichloro- or -fluoroacetate, and also C1-C12-alcoholates, such as straight chain or branched C1-C12alcoholates, e.g. methanolate or ethanolate.
Anionic ligands and neutral may also be present up to the preferred coordination number of the complex cation, especially four, five or six. Additional negative charges are counterbalanced by cations, especially monovalent cations such as Na+, K+, NH4+ or (C1-C4 alkyl)4N+.
Suitable neutral ligands are inorganic or organic neutral ligands commonly known in complex chemistry of transition metals. They coordinate to the metal ion through a σ-, π-, μ-, η-type bonding or any combinations thereof up to the preferred coordination number of the complex cation. Suitable inorganic ligands are selected from the group consisting of aquo (H2O), amino, nitrogen, carbon monoxide and nitrosyl. Suitable organic ligands are selected from the group consisting of phosphines, e.g. (C6H5)3P, (i-C3H7)3P, (C5H9)3P or (C5H11)3P, di-, tri-, tetra- and hydroxyamines, such as ethylenediamine, ethylenediaminetetraacetate (EDTA), N,N-Dimethyl-N′,N′-bis(2-dimethylaminoethyl)ethylenediamine (Me6TREN), catechol, N,N′-dimethyl-1,2benzenediamine, 2-methylamino)phenol, 3-(methylamino)-2-butanol or N,N′-bis(1,1-dimethylethyl)-1,2-ethanediamine, N,N,N′,N″,N″-pentamethyldiethyltriamine (PMD-ETA), C1-C8-glycols or glycerides, e.g. ethylene or propylene glycol or derivatives thereof, e.g. di-, tri- or tetraglyme, and monodentate or bidentate heterocyclic e− donor ligands.
Heterocyclic e− donor ligands are derived, for example, from unsubstituted or substituted heteroarenes from the group consisting of furan, thiophene, pyrrole, pyridine, bis-pyridine, picolylimine, g-pyran, g-thiopyran, phenanthroline, pyrimidine, bis-pyrimidine, pyrazine; indole, coumarone, thioniaphthene; carbazole, dibenzofuran, dibenzothiophene, pyrazole, imidazole, benzimidazole, oxazole, thiazole, bis-thiazole, isoxazole, isothiazole, quinoline, bis-quinoline, isoquinoline, bis-isoquinoline, acridine, chromene, phenazine, phenoxazine, phenothiazine, triazine, thianthrene, purine, bis-imidazole and bis-oxazole.
The oxidizable transition metal complex catalyst can be formed in a separate preliminary reaction step from its ligands or is preferably formed in-situ from its transition metal salt, e.g. Cu(I)Cl, which is then converted to the complex compound by addition of compounds corresponding to the ligands present in the complex catalyst, e.g. by addition of ethylenediamine, EDTA, Me8TREN or PMDETA.
Preferred is a composition, wherein in the step a3) the oxidizable transition metal in the transition metal complex salt is present as a transition metal complex ion in the lower oxidation state of a redox system.
More preferred is a composition, wherein the transition metal complex ion is a Cu(I) complex ion in the Cu(I)/Cu(II) system.
Routs a3) is carried out when comb copolymers are prepared. The preparation of comb copolymers by the ATRP method is for example described in WO 01/51534.
The elimination of the transfer group —Y. e. g. halogen, wit a polymerizable chain terminating group —X is advantageously performed in such a way that the polymerisate is dissolved in a solvent and the monomeric compound corresponding to —X is added in the presence of a non-nucleophilic base, such as diazabicycloundecene (DBU) or similar bases, at elevated temperatures. The reaction, which is a conventional esterification reaction, takes place under conditions of a regular esterification reaction within a temperature range, for example from room temperature to 100° C.
Preferably the nitroxylether of step a1) or the nitroxyl radical of step a2) is present in an amount of from 0.001 mol-% to 20 mol-%, more preferably of from 0.002 mol-% to 10 mol-% and most preferably of from 0.005 mol-% to 5 mol-% based on the monomer or monomer mixture.
Preferably the free radical initiator is present in an amount of 0.001 mol-% to 20 mol-%; based on the monomer or monomer miture.
The molar ratio of free radical initiator to stable free nitroxyl radical is preferably from 20:1 to 1:2, more preferably from 10:1 to 1:2.
Scission of the O—X bond of the nitroxylether may be effected by ultrasonic treatment, radiation with actinic light or heating.
The scission of the O—X bond is preferably effected by heating and takes place at a temperature of between 50° C. and 180° C., more preferably from 90° C. to 150° C.
The initiator of formula (III),
and the oxidizable transition metal are for example present in an amount of 1:10 to 1:100, relative to the monomer. The total amount of oxidizable transition metal to initiator of formula (III) is for e)ample from 0.05:1 to 2:1, in particular from 0.2:1 to 0.5:1.
The polymerization reaction is carried out with preference under atmospheric pressure. In the block or comb copolymer the nonionic polymer block B is composed of non-ionic repeating units of ethylenically unsaturated monomers suitable for the method of controlled or living polymerisation. These monomers are characterised by the presence of at least one group >C═C< Representative monomers are selected from the group consisting of styrenes, acrylic and C1-4alkylacrylic acid-C1-C24alkyl esters, acrylic and C1-C4alkylacrylic acid-C6-C11aryl-C1-C4alkyl esters, acrylic and C1-C4alkylacrylic acid-C6-C11aryloxy-C1-C4alkyl esters, acrylic and C1-C4alkylacrylic acid-hydroxy-C2-C8alkyl esters, acrylic and C1-C4alkylacrylic acid-polyhydroxy-C3-C6alkyl esters, acrylic and C1-C4alkylacrylic acid-(C1-C4alkyl)3silyl-oxy-C2-C4alkyl esters; acrylic and C1-C4alkylacrylic acid-(C1-C4alkyl)3silyl-C1-C4alkyl esters, acrylic and C1-C4alkylacrylic acid-heterocyclic-C2-C4alkyl esters; acrylic and C1-C4alkylacrylic add esters having poly-C2-C4alkyleneglycolester groups, wherein the ester groups may be substituted with C1-C24alkoxy groups, acrylic and methacrylic acid amides, acrylic and C1-C4alkylacrylic -acid-(C1-C4alkyl)1-2amide, acrylonitrile, esters of maleic acid or fumaric acid, maleinimide and N-substituted maleinimides.
In a preferred embodiment of the invention the nonionic polymer block B is essentially composed of repeating units of ethylenically unsaturated monomers selected from the group consisting of styrenes, acrylic and methacrylic acid-C1-C24alkyl esters, acrylic and meth-acrylic acid-hydroxy-C2-C6alkyl esters, acrylic and methacrylic acid-dihydroxy-C3-C4alkyl esters and acrylic and methacrylic acid esters having poly-C4-C4alkyleneglycolester groups, wherein the ester groups may be substituted with C1-C24alkoxy groups.
Suitable styrenes may be substituted at the phenyl group by one to three additional substituants selected from the group consisting of hydroxy, C1-C4alkoxy, e.g. methoxy or ethoxy, halogen, e.g. chloro, and C1-C4alkyl, e.g. methyl or methyl.
Suitable acrylic acid or methacrylic add-C1-C24alkyl esters are acrylic acid or methacrylic acid esters esterified by methyl, ethyl, n-butyl, isobutyl, tert-butyl, neopentyl, 2-ethylhexyl, isobornyl, isodecyl, n-dodecyl, n-tetradecyl, n-hexadecyl or n-octadecyl.
Representative acrylic and C1-C4alkylacrylic acid-C8-C11aryl-C1-C4alkyl esters are acrylic acid or methacrylic acid esters esterified by benzyl, 2-phenylethyl, 1- or 2-naphthylmethyl or 2-(1- or 2-naphthyl)-ethyl. The phenyl or naphthyl groups may be additionally substituted with one to three additional substituents selected from the group consisting of hydroxy, C1-C4alkoxy, e.g. methoxy or ethoxy, halogen, e.g. chloro, and C1-C4alkyl, e.g. methyl or methyl.
Representative acrylic and C1-C4alkylacrylic acid C8-C11aryloxy-C1-C4alkyl esters are acrylic acid or methacrylic acid esters esterified by phenoxyethyl or benzyloxyethyl.
Representative acrylic acid and C1-C4alkylacrylic acid-hydroxy-C2-C4alkyl esters are acrylic acid- or methacrylic acid-2-hydroxyethylesters (HEA, HEMA) or acrylic acid- or methacrylic acid-2-hydroxypropylester (HPA, HPMA).
Representative acrylic and C1-C4alkylacrylic acid-polyhydroxy-C3-C6alkyl esters are acrylic acid- or methacrylic acid esterified by ethylene glycol or glycerol.
Representative acrylic acid- and C1-C4alkylacrylic acid-silyloxy-C2-C4alkyl ester are acrylic acid- or methacrylic acid-2-trimethylsilyloxyethylesters (TMS-HEA, TMS-HEMA).
Representative acrylic acid- or C1-C4alkylacrylic acid-(C1-C4alkyl)3silyl-C2-C4alkyl esters are acrylic acid- or methacrylic acid-2-trimethylsilylethylesters or acrylic acid- or methacrylic acid-3-trimethylsilyl-n-propylesters.
Representative acrylic and C1-C4alkylacrylic acid esters having poly-C2-C4alkyleneglycolester groups, wherein the ester groups may be substituted with C1-C24alkoxy groups, are illustrated by the formula given below:
wherein
n represents a numeral from one to 100;
R1 and R2 independently of one another represent hydrogen or methyl; and
R3 represents C1-C24alkyl, e.g. methyl, ethyl, n- or isopropyl, n-, iso-, or tert-butyl, n- or neo-pentyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, or represents aryl-C1-C24alkyl, e.g. benzyl or phenyl-n-nonyl, as well as C1-C24alkylaryl or C1-C24alkylaryl-C1-C24alkyl.
Representative acrylic acid- and C1-C4alkylacrylic acid-heterocyclyl-C2-C4alkyl esters are acrylic acid- or methacrylic acid-2-(N-morpholinyl, 2-pyridyl, 1-imidazolyl, 2-oxo-1-pyrrolidinyl, 4-methylpiperidin-1-yl or 2oxoimidazolidin-1-yl)-ethyl esters.
Representative C1-C4alkylacrylic acid esters having poly-C2-C4alkyleneglycolester groups, wherein the ester groups may be substituted with C1-C24alkoxy groups are acrylic acid- or methacrylic acid esters of ethoxylated decanol, ethoxylated lauryl alcohol or ethoxylated stearyl alcohol, wherein the degree of ethoxylation, as expressed by the index n in the formula above, is typically in the range from 5 to 30.
Representative acrylic and C1-C4alkylacrylic acid-C1-C4allyl)1-2amide are acrylic acid- or methacrylic acid N-methyl, N,N-dimethyl, N-ethyl or N,N-diethyl amide.
Representative esters of maleic acid or fumaric acid are the C1-C24alkyl esters, e.g. the methyl, ethyl, n-butyl, isobutyl, tert-butyl, neopentyl, 2-ethylhexyl, isobornyl, isodecyl, n-dodecyl, n-tetradecyl, n-hexadecyl or n-octadecyl esters, the C8-C11aryl, e.g. phenyl or naphthyl, esters or the C6-C11aryl-C1-C4alkyl esters, e. g. benzyl or 2-phenethyl esters. The phenyl or naphthyl groups may be additionally substituted with one to three additional substituents selected from the group consisting of hydroxy, C1-C4alkoxy, e.g. methoxy or ethoxy, halogen, e.g. chloro, and C1-C4alkyl, e.g. methyl or methyl.
Representative N-substituted maleinimides are the N—C1-C4alkyl, e.g. N-methyl or N-ethyl, or N-aryl, e.g. N-phenyl substituted maleinimides.
In the comb or block copolymer the polymer block A additionally contains repeating units of ethylenically unsaturated monomers substituted with cationic groups. A suitable cationic polymer block A is essentially composed of repeating units of ethylenically unsaturated monomers represented by the cationic part of a salt formed by quaternisation of an amino monomer selected from the group consisting of amino substituted styrene, (C1-C4alkyl)1-2amino substituted styrene, N-mono-(C1-C4alkyl)1-2amino-C2-C4alkyl(meth)acrylamide and N,N-di-(C1-C4alkyl)1-2amino-C2-C4alkyl(meth)acrylamide, vinylpyridine or C1-C4alkyl substituted vinylpyridine, vinylimidazole and C1-C4alkyl substituted vinylimidazole and a compound of the formula
CH2═C(—R1)—C(═O)—Re (V),
In a particularly preferred embodiment of the invention the repeating unit of an ethylenically unsaturated monomer substituted with an cationic group is represented by the cationic part of a salt formed from a compound of the formula (V), wherein
R1 represents hydrogen or methyl; and
R2 represents amino substituted C2-C10alkoxy selected from the group consisting of amino-C2-C4alkoxy, C1-C4alkylamino-C2C4alkoxy, di-C1-C4alkylamino-C2-C4alkoxy, hydroxy-C2C4-alkylamino-C2-C18alkoxy and C1-C4alkyl-(hydroxy-C2-C4alkyl)amino-C2-C4alkoxy.
In an alternative embodiment the repeating unit of an ethylenically unsaturated monomer is the acid addition salt or the salt formed by quaternisation of an amino monomer selected from the group consisting of amino substituted styrene, (C1-C4alkyl)1-2amino substituted styrene N-mono-(C1-C4alkyl)1-2aminoC2-C4alkyl(meth)acrylamide and N,N-di-(C1-C4alkyl)1-2amino-C2-C4alkyl(meth)acrylamide, vinylpyridine or C1-C4alkyl substituted vinylpyridine, vinylimidazole and C1-C4alkyl substituted vinylimidazole.
Representative styrenes are substituted at the phenyl group with one or two amino groups or one or two (C1-C4alkyl)1-2 amino groups, particularly one amino group in 4-position. Additional substituents are selected from the group consisting of hydroxy, C1-C4alkoxy, e.g. methoxy or ethoxy, halogen, e.g. chloro, or C1-C4alkyl, e.g. methyl or ethyl.
Representative N-mono-(C1-C4alkyl)1-2amino-C2-C4alkyl(meth)acrylamide, and N,N-di-(C1-C4alkyl)1-2amino-C4alkyl(meth)acrylamide are 2N-tert-butylamino- or 2-N,N-dimethyl-aminoethylacrylamide or 2-N-tertbutylamino- or 2-N,N-dimethylaminopropylmethacrylamide. In another preferred embodiment of the invention the repeating unit of an ethylenically unsaturated monomer substituted with an ionic group present in one of the polymer blocks A and B is the acid addition salt or the salt formed by quaternisation of an amino monomer selected from the group consisting of amino substituted styrene, (C1-C4alkyl)1-2amino substituted styrene, and N,N-di-(C1-C4alkyl)2amino-C2-C4alkyl(meth)acrylamide.
For example the cationic part of a salt according to formula (V) is represented by an ester group of the formula (C)
Ra, Rb and Rc independently of one another represent hydrogen or a substituent selected from the group consisting of C1-C4alkyl, aryl-C1-C4alkyl and (C1-C4alkyl)1-3aryl.
In an especially preferred embodiment of the invention the repeating unit of an ethylenically unsaturated monomer substituted with an ionic group is represented by the cationic part of an acid addition salt or the salt formed by quaternisation of 4-aminostyrene, 4-dimethylaminostyrene and an aminoalkyl (meth)acrylates selected from the group consisting of 2-dimethylaminoethyl acrylate (DMAEA), 2-dimethylaminoethyl methacrylate (DMAEMA), 2-diethylaminoethyl acrylate (DEAEA), 2-diethylaminoethyl methacrylate (DEAEMA), 2-t-butylamino-ethyl acrylate (tBAEA), 2-t-butylaminoethyl methacrylate (t-BAEMA) and 3-dimethylamino-propylmethacrylamide, 4-vinylpyridine, 2-vinylpyridine or 1-vinylimidazole.
For example the number of repeating units of the nonionic block B is from 4-1000.
For instance the number of repeating units of the cationic block A is from 1-100.
In a specific embodiment of the invention the non-ionic block B is composed of butylacrylate (BA) and the ionic block A is composed of 2-dimethylaminoethyl acrylate (DMAEA) or 2-dimethylaminoethyl methacrylate (DMAEMA). In order to get a maximized exploitation the length of the total blocks is for example more than 30 units. However in some cases also lower length may provide a sufficient intercalation and exfoliation.
Typical blockpolymers are for example Poly (BA)16-block-(DMAEA)4,5 or Poly (BA)68-block-DMAEA)19.
The counterion present in the salt forming component free amino group or a primary, secondary or tertiary amino group may be the anion of a carboxylic acid, phosphonic acid, sulfonic acid, mineralic acid or complex acid. Examples of the anions of mineral acids are F−, Cl−, Br− or I−. Examples for the anions of complex acids are ClO4−, SbF8− or PtF6−.
In a specific embodiment of the invention the counterion of the salt forming component is selected from the group consisting of mono-, bi- or tricyclic sulphonic, carboxylic or phosphonic acids and aliphatic sulphonic, carboxylic or phosphonic acids substituted with mono-, bi- or tricyclic groups alkyl halides substituted with mono-, bi- or tricyclic groups, and C1-C4alkyl esters of mono-, bi- or tricyclic sulphonic acids.
The mono-, bi-, or tricyclic groups present in the sulphonic, carboxylic and phosphonic acids or the mono-, bi-, or tricyclic substituants of the aliphatic sulphonic, carboxylic or phosphonic acids and alkyl halides are selected from the group consisting of saturated or unsaturated mono-, bi-, or tricyclosliphatic, heteromonocycloaliphatic or heterobicycloaliphatic, carbomonocyclic or carbobicyclic aromatic, partially saturated carbobicyclic aromatic, heteromonocyclic or heterobicyclic aromatic and partially saturated heterobicyclic aromatic groups.
Representative salt forming components which are selected from the group consisting of mono-, bi-, or tricyclic sulphonic, carboxylic and phosphonic acids or represent salt forming components which are selected from the group of aliphatic sulphonic, carboxylic or phosphonic acids substituted with monocyclic, bicyclic or tricyclic groups are illustrated by the list given below:
A preferred group of substituted mono-, bi-, or tricyclic sulphonic, carboxylic and phosphonic acids is represented by the general formula:
wherein
X represents carboxy, sulpho or P(═O)(OH)2; and
R1, R2 or R3 independently of one another represent hydrogen or a substituent selected from the group consisting of functional groups or derivatised functional groups selected from the group consisting of amino, C1-C4alkylamino, C1-C4-dialkylamino, hydroxy, oxo, thio, —NO2, carboxy, carbamoyl, sulpho, sulphamoyl, ammonia, amidino, cyano, formylamino, formamido and halogen; or
R1, R2 or R3 independently of one another represent saturated or unsaturated aliphatic, cycloaliphatic or heterocycloaliphatic groups, carbocyclic or heterocyclic aryl groups, condensed carbocyclic, heterocyclic or carbocyclic-heterocyclic groups, which may additionally be combined with one of these groups or which may additionally be substituted with one of the functional groups or derivatised functional groups mentioned above.
The substituent groups may additionally be interrupted with one or more bivalent groups selected from the group consisting of —O—, —S—, —C(═O)—O—, —O—C(═O)—, —C(═O)—N(C1-C4alkyl)-, —N(C1-C4alkyl)-C(═O)—, —S(═O)—, —S(═O)2—, —S(═O)—O—, —S(═O)2—O—, —O—S(═O)—, —O—S(═O)2—, —S(═O)—N(C1-C4allyl)-, —S(═O)2—N(C1-C4alkyl)-, —(C1-C4alkyl)N—S(═O)—, —(C1-C4alkyl)N—S(═O)2—, —P(═O)—, —P(═O)—O—, —O—P(═O)— and —O—P(═O)—O—.
Two substituents from the group R1 and R2 may also represent bhalent, bridge-types C2-C0alkylen-, C4-C6alkyldiyliden- or C4-C8alkenyldiyliden groups which are connected with one of the above-mentioned cyclic or bicyclic groups.
Specific salt forming components, which are selected from the group consisting of mono- or bicyclic sulphonic acids, are illustrated by their structural formulae given below.
Further specific salt forming components, which are selected from the group consisting of mono- or bicyclic sulphonic acids are illustrated by their structural formulae given below:
Specific salt forming components, which are selected from the group consisting of mono- or bicyclic carboxylic acids are illustrated by their structural formulae given below:
Further specific salt forming components, which are selected from the group consisting of mono- or bicyclic carboxylic acids and phosphonic acids are illustrated by their structural formulae given below:
Typically the block or comb copolymer is added to the natural or synthetic clay in an amount of from 1% to 1000% by weight, based on the weight of the clay, preferably of from 20% to 400% and more preferably from 50% to 400%.
Preferably the polydispersity of block A and B is between 1 and 2.
In particular the polydispersity of the blockoopolymer A-B is between 1 and 2.
A further aspect of the invention is a block or comb copolymer, clay nanocomposite dispersion obtainable by a process as described above.
The intercalated clay can, for example be isolated as a powder. The isolation process may be carried out, for example, by centrifugating the corresponding aqueous dispersion. Another possibility is, to completely evaporate water and solvents and subject the solid residue to a Soxhlet extraction with a suitable organic solvent, to remove excess polymer. Suitable organic solvents are, for example, esters, ethers or aromatic solvents. The purified solid material can easily be redispersed in water to result in a clay nanocompsite dispersion.
The nanocomposite dispersions are useful for example in, coatings, sealants, caulks, adhesives and as plastic additives to modify the physical properties of the final products.
Typically scratch resistance or water vapour permeation of coatings or polymer films are advantageously influenced by the addition of the instant nanocomposite dispersions.
It is typical for nanocompsite dispersions, that considerable less must be added for example to a coating as compared to conventional additives to achieve the same or even a better effect in many cases even transparency of the coating is retained.
Use of a block copolymer having one ammonium cationic block A, and at least one neutral block B or a comb copolymer having an ammonium ion containing cationic backbone A and neutral oligomeric polymeric chains B attached thereto, wherein the block copolymer and the comb copolymer is obtained by controlled free radical polymerization as described above for the preparation of nanocomposite dispersions of natural or synthetic clay.
The following examples illustrate the invention.
A block-copolymer of n-butyl acrylate and dimethyl aminoethyl acrylate (DMAEA) was synthesized by ATRP:
n=7.7, m=2.0; GPC: Mn=1710, Mw=2050, PDI=1.20; N-content: 1.62 wt. % (elemental analysis)
A) Preparation of the first block, poly-n-butylacrylate with terminal Br-groups:
1282 g (10.0 mol) n-butylacrylate (BASF, tech. quality), 1282 g acetone (Fluka purum), 28.45 9 (0.2 mol) CuBr and 2.23 g (0.01 mol) CuBr2 are added to a 4500 ml round flask equipped with a mechanical stirrer. The air is removed from the flask by stirring and evacuating and rinsing with nitrogen three times. 34.7 9 (0.2 mol) PMDETA (N,N,N′,N″,N″-pentamethyldiethyltriamine: Fluka/purum) are added through the rubber sealing with a syringe and the mixture homogenized by stirring.
After addition of 167 g (1 mol) methyl-2-bromo-propionate (MBP, =initiator) with a syringe and heating up to 60° C. in the oil bath the exothermal polymerization reaction is started and is controlled by ice cooling to T=60-65° C. The mixture is polymerized for 7.5 h. The conversion (77%) is determined by 1HNMR-analysis in CDCl3 (08% after 75 Min.) After cooling to room temperature 300 g neutral aluminum oxide (ALOX for chromatography, Merck) are added. After stirring the mixture for 1 h, filtration and drying in the rotary evaporator at 80° C., additional drying with a vacuum pump the polymer (slightly yellow, dear liquid) is obtained.
Yield: 1192 g (98%). Elementary analysis:
Cu: <10 ppm (X-ray fluorescence); GPC (THF): Mn: 1150, Mw: 1370, PDI: 1.19. (92%).
B) Preparation of the block copolymer of n-butylacrylate and 2-dimethylaminoethyl acrylate:
200 g poly-n-butylacrylate (0.18 mol Br, Ex. 1A) and 5.16 g (0.036 mol) CuBr (Fluka, purum) are added to a 750 ml round flask equipped with a mechanical stirrer. The air is removed from the flask by stirring and evacuating and rinsing with nitrogen three times. The mixture is stirred and 51.5 g (0.36 mol) 2-dimethylaminoethyl acrylate (DMAEA, BASF, technical quality) are added through the rubber sealing with a syringe. The air is removed again from the flask by evacuating and rinsing with nitrogen three times. 6.24 g (0.036 mol) PMDETA (Fluka/purum) are added with a syringe, and the mixture is made homogeneous by stirring. After heating up to 90° C. in the oil bath the slightly exothermal polymerization reaction is started and the mixture is polymerized for 30 min. The conversion of DMAEA is quantitative, as determined by 1H-NMR-analysis in CDCl3. After cooling to room temperature 250 ml ethyl acetate and 110 g neutral aluminum oxide (Alox® for chromatography) are added and the mixture stirred for 1.5 h. The polymer is obtained after filtration and drying in the rotary evaporator at 80° C. with a vacuum pump. Yield: 155.6 g (62 %).
Elementary analysis:
GPC (THF): Mn: 1720, Mw: 2020, PDI: 1.18.
C) Protonation of the block copolymer with p-toluene sulfonic acid:
In a 500 ml round bottom flask with mechanical stirring, 145 g of the copolymer is dissolved in 60.8 g 1-methoxy-2-propanol (Dowanol PM) and a solution of 31.9 g p-toluene sulfonic acid monohydrate (Fluka purum), dissolved in 200 g hot Dowanol PM, is slowly added with good stirring during 1 h at room temperature. A clear, slightly yellow solution with 40 wt. % solid content of the cationic block copolymer is obtained.
D) Intercalation of sheet silicates (Nanofil EXM 588 from Süd Chemie, Germany; sheet silicate of Montmorillonite-type) with cationic block copolymer Poly(BA-b-DMAEA) described under C).
22.9 g of the above solution containing 9.15 9 of the cationic block copolymer A) is put into a 100 ml round bottom flask with mechanical stirring, 30 9 Dowanol PM and 5 9 water are added. 3.49 g Nanofil EXM 588 (Süd Chemie, Germany) is dispersed in this mixture, homogenized and stirred for 24 h at 60° C. It is then centrifuged (IEC Centra GP8 Centrifuge) with 2000 rpm (corresponding to ca. 850 g) during 1 h, the supernatend is decanted and the, solid residue at the bottom is washed with EtOH and again centrifuged for 1 h at 2000 rpm. After again decanting the supernatend, the procedure is repeated once more with a water/EtOH 1/1 (vol) mixture. The solid is dried in vacuum (0.1 mbar) at 50° C. for 24 h. Yield: 4.0 g.
Analysis:
TGA: The amount of adsorbed organic material (cationic block copolymer) is determined by thermogravimetric analysis (TGA): heating rate: 10° C./min, from room temperature to 600° C. The observed weight loss of 30% corresponds to a solid content of 70 wt. %.
GPC: A direct measurement of the sample is not possible because the polymer chains are tightly attached to the sheet silicate will not pass the GPC columns. Therefore, a sample (150 mg) of this solid is refluxed with 15 ml 0.2 M LiBr solution in THF during 17 h at 65° C., to cleave off the polymer from the sheet silicate. After filtration, the molar mass (Mn) and PDI is determined by GPC in THF (relative to PS-standards): Mn=1450, Mw=2050 and PDI=1.42, correspond well to the data of the block-copolymer used for intercalation.
Powder X-ray: The product is also subjected to a powder X-ray (λ=1.54 Angström), giving an interlayer distance of 1.96 nm. Compared with the native sheet silicate (d=1.24 nm) an increase of the interlayer distance of 0.72 nm is obseved, corresponding to approximately the size of the intercalated cationic block-copolymer. The reflex at the original sheet distance has completely disappeared.
E) intercalation of an artificial sheet silicate Optigel SH (Süd Chemie, Germany) with the cationic block copolymer Poly(BA63-b-DMAEMA19) with 68 BA and 19 DMAEMA units, synthesized as described under A and B and protonated as described under C.
770.3 g of a 30 wt. % solution of the cationic block copolymer Poly(BA68-b-DMAEMA19) in Dowanol PM (Fluka, puriss p.a.), 50% of the DMAEMA units neutralized with p-toluene sulfonic acid as described in C, are put into a 2.5 L round bottom flask with mechanical stirring. 1.4 Dowanol PM and 140 ml water are added. 120 g Optigel SH (Süd Chemie, Germany) is dispersed in this mixture, homogenized and stirred for 24 h at 60° C. The solvents are evaporated in a rotavap and the solid residue extracted in a 1 L Soxhlet extractor, first 12 h with 2 L ethyl acetate, then 4 h with 2 L ethanol and finally 14 h with 2 L ethanol/water 1:1 mixture. The gray solid is redispersed in EtOH, filtered and dried in vacuum (0.1 mbar) at 55° C. for 24 h. Yield: 255.5 g of a white powder is obtained.
Analysis:
TGA: The amount of adsorbed organic material (cationic block copolymer) is determined as before, giving 54 wt. % (=46 wt. % solid content).
GPC: (Sample preparation as before) Mn=10000, Mw=14300, PDI=1.43.
Powder X-ray: Complete exfoliation with interlayer distance d>3 nm.
A) in analogy to Example 1, a longer block-copolymer of n-butyl acrylate and dimethyl aminoethyl acrylate (DMAEA) is synthesized.
Analysis: n=27.6, m=8.7; Mn=6270, Mw=7710, PDI=1.23
100% of the amino groups are neutralized with p-toluene sulfonic acid monohydrate Dowanol PM to a dear, slightly yellow solution with 30.5 wt. % solid content of the cationic block copolymer.
E) intercalation of a sheet silicate with a longer cationic black copolymer Poly(BA-b-DMAEA) prepared as described under A)
300 g of above solution containing 91.5 g of the cationic block copolymer A) is put into a 1000 ml round bottom flask with mechanical stirring and 250 g Dowanol PM and 50 g water are added. 34.9 g Nanofil EXM 588 (Süd Chemie, Germany) is dispersed in this mixture with a high speed Ultraturax mixer, homogenized and stirred for 24 h at 60° C. It is then centrifuged (2000 rpm) during 1 h, the supernatend is decanted and the solid residue at the bottom dispersed in 300 ml ethyl acetate and again centrifuged for 1 h at 2000 rpm. After again decanting, the supernatend, the solid is redispersed in 300 ml EtOH with an Ultraturax and centrifuged again for 1 h. The gray solid is-redispersed in a water/EtOH 4/1 (vol) mixture and filtered. The solid is dried in vacuum (0.1 mbar) at 40° C. for 24 h. Yield: 26.3 g.
Analysis:
TGA: Observed weight loss: 46% corresponding to a solid content of 54 wt. %.
GPC: After refluxing with LiBr in THF at 65° C. (to cleave off the polymer from the sheet silicate): Mn=3700, Mw=7240, PDI=1.82.
Powder X-ray: No reflexions above 2Θ=30, corrsponding to an interlayer distance of >3 nm: complete exfoliation.
A) A comb-copolymer of a poly(n-butyl acrylate) macromonomer (synthesized by ATRP) and dimethyl aminoethyl methacrylate (DMAEMA) is first synthesized according to known procedures (see e.g. WO-01/051534):
Synthesis of the poly(n-butyl acrylate) macromonomer (with methacrylate functional groups):
7.46 g (0.052 mol) Cu(I)Br is added into a 2.5 I reaction vessel (evacuated and rinsed with N2 5 times) followed by the addition of 1000 g (7.80 mol) n-butyl acrylate and 350 ml acetone. The reaction mature is homogenized by mechanical stirring. 9.0 g (0.052 mol) PMDETA are added with a syringe and a green solution is obtained. After adding 43.43 g (0.26 mol) methyl-2bromopropionate as the initiator, the mixture is heated to 60° C. The highly exothermic reaction requires cooling with ice to maintain the temperature at about 60° C. for4 h: Conversion: 74% (1H-NMR analysis). The reaction mixture is cooled to room temperature and the solvents are evaporated in the rotary evaporator. After diluting the residue with 300 ml ethylacetate 2×150 g SiO2 are added. The mixture is filtered and directly converted to the macromonomer as follows:
26.86 g (0.31 mol. 1.2 eq.) methacrylic acid and 47.51 g (0.31 mol. 1.2 eq.) DBU are ; added to the reaction mixture, which is then stirred at room temperature for 15 hours. After, filtration 200 g SiO2 are added. The reaction mixture is stirred for a half hour and filtered, again. The solvents are evaporated in the rotary evaporator and the macromonomer dried at 100° C. in high vacuum (p<0.1 mbar). Yield: 803.3 g (97.5%) of a slightly yellow transparent viscous liquid. Analytical data:
GPC (THF, PS-standards): Mn: 3600, PDI=1.13.
Radical copolymerization of this macromonomer with N,N-dimethylaminoethyl methacrylate (DMAEA):
300 g (0.081 mol, 78 wt %) of above macromonomer, 84.6 9 (0.54 mol, 22 wt %) N,N-dimethylaminoethyl acrylate (DMAEMA), 640 ml 1-methoxy-2-propanol and 7.7 g (2 wt. %, relative to the monomers) AIBN, are introduced into a 1.51 reactor (evacuated and rinsed 3 times with N2). The homogeneous mixture is polymerized at 60° C. (exothermic reaction) during 24 h. This mixture containing the comb-copolymer is directly used for tests as a pigment dispersant. Analytical data of dried sample:
GPC (THF, PS-standards): Mn=34500, PDI=3.0.
This comb-polymer, containing 62 wt. % n-BA units and 38 wt. % DMAEMA units (according to 1H-NMR) is neutralized in Dowanol PM with p-toluene sulfonic acid monohydrate as described in Examples 1 and 2 (100% of the amino groups are quaternised). A clear, slightly yellow solution with 29.8 wt. % solid content of the catlonic comb-copolymer is obtained.
B) Intercalation of a sheet silicate with a cationic comb-copolymer described under A) 513.7 g of the above solution containing 150 g of the cationic comb-copolymer A) is put into a 2 L round bottom flask with mechanical stirring and 500 g Dowanol PM and 100 g water are added 60.3 g Nanofil EXM 588 (Süd Chemie, Germany) is dispersed in this mixture with a high speed Ultraturax mixer, homogenized and stirred for 24 h at 60° C. It is than centrifuged (2000 rpm) during 1 h, the supernatend is decanted and the solid residue at the bottom is dispersed in 600 ml ethyl acetate and again centrifuged for 1 h at 2000 rpm. After again decanting the supernatend, the solid is redispersed in 600 ml EtOH with an Ultraturax and centrifuged again for 1 h. The gray solid is redispersed in 600 ml water, filtered, washed with EtOH and filtered again. The solid is dried in vacuum (0.1 mbar) at 50° C. for 24 h. Yield: 50.5 G.
Analysis:
TGA: Observed weight loss: 54% corresponding to a solid content of 46 wt. %.
GPC: After refluxing with LiBr in THF/water for 17 h at 65° C.: Mn=32800, Mw=61600, PDI=1.87.
Powder X-ray: No reflexions above 2Θ=3°, corrsponding to an interlayer distance of >3 nm: complete exfoliation.
A) The same comb-copolymer of a poly(n-butyl acrylate) macromonomer (synthesized by ATRP) and dimethyl aminoethyl methacrylate (DMAEMA) as described in example 3 A) is used, but only 50% of the amino groups are neutralind in Dowanol PM with p-toluene sulfonic acid monohydrate. A dear, slightly yellow solution with 30.0 wt. % solid content of the cationic comb-copolymer is obtained.
B) intercalation of a sheet silicate with a cationic comb copolymer 213.5 g of above solution containing 64.05 g of the cationic comb-copolymer is put into a 1 L round bottom flask with mechanical stirring and 175 g Dowanol PM and 35 g water are added. 24.4 g Nanofil EXM 588 (Süd Chemie, Germany) is dispersed in this mixture with a high speed Ultraturax mixture, homogenized and stirred for 24 h at 60° C. It is then centrifuged (2000 rpm) during 1 h, the supernatend is decanted and the solid residue at the bottom is dispersed in ethyl acetate and again centrifuged for 1 h at 2000 rpm. After again decanting the supernatend, the solid is redispersed in EtOH with an Ultraturax and centrifuged again for 1 h. The gray solid is redispersed in water, filtered, washed with EtOH and filtered again. The solid is dried in vacuum (0.1 mbar) at 50° C. for 24 h. Yield: 27.5 g.
Analysis:
TGA: Observed weight loss: 49% corresponding to a solid content of 51 wt. %.
GPC: As in example 3, Mn=27100, Mw=45000, PDI=1.67.
Powder X-ray: No reflexions above 2Θ=3°, corresponding to an interlayer distance of >3 nm: complete exfoliation
C) intercalation of another sheet silicate (Harshaw Filtrol Grade 13) with a cationic comb-copolymer
492 g of the solution according to A) containing 137.3 g of the cationic comb-copolymer is put into a 2.5 L round bottom flask with mechanical stirring and 1.44 L Dowanol PM and 144 ml water are added. 120 g Harshaw Filtrol Grade 13 (Engelhard Process Chemicals GmbH, Nienburg, Germany) is dispersed in this mixture with a high speed Ultraturax mixture, homogenized and stirred for 24 h at 60° C. The solvents are evaporated in a rotavap and the solid residue extracted in a 1 L Soxhlet extractor, first 12 h with 2 L ethyl acetate, then 12 h with 2 L ethanol and finally 12 h with 2 L ethanol/water 1:1 mixture. The gray solid is redispersed in EtOH, filtered and dried in vacuum (0.1 mbar) at 55° C. for 24 h. Yield: 148.5 g.
Analysis:
TGA: Observed weight loss: 39 wt. % corresponding to a solid content of 61 wt. %.
Powder X-ray: No reflexions above 2Θ=30, corresponding to an interlayer distance of >3 nm: complete exfoliation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03405139.1 | Mar 2003 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP04/50184 | 2/23/2004 | WO | 8/29/2005 |
