WO2003033556A1

WO2003033556A1 - Method for producing substituted polymethacrylimides from poly-alkylmethacrylamide-co-alkylmethacrylates, using cyclodextrins

Info

Publication number: WO2003033556A1
Application number: PCT/EP2002/011487
Authority: WO
Inventors: Peter Stein; Helmut Ritter; Sabine Schwarz-Barac
Original assignee: Röhm GmbH & Co. KG
Priority date: 2001-10-16
Filing date: 2002-10-15
Publication date: 2003-04-24
Also published as: DE10150484A1

Abstract

The invention relates to a method for producing substituted polymethacrylimides by the intramolecular reaction of polymers, said polymers being produced from water-insoluble and optionally water-soluble monomers by the radical polymerisation of monomers in water, which acts as the diluent, whereby the water-insoluble or slightly water-soluble monomers are polymerised in the form of complexes of a) cyclodextrins and compounds containing cyclodextrin structures. The substituted polymethacrylimides are synthesised by a thermal treatment of the copolymers.

Description

Process for the preparation of substituted polymethacrylimides from poly-alkyl methacrylamide-co-alkyl methacrylates using cyclodextrins

Technical field of the invention

The invention relates to a process for the preparation of polymethacrylimides by thermolysis of a copolymer of a slightly water-soluble and a water-insoluble monomer, which is prepared by radical polymerization in a water-containing diluent in the presence of cyclodextrins.

State of the art

Polymethacrylimides are used on an industrial scale in two forms of derivatization. On the one hand, the poly-N-methyl methacrylimide (PMMI) is to be mentioned, which is available under the trade name PLEXIMID ^® . PMMI is a highly heat-resistant, transparent plastic with high UV stability. PMMI is used as an injection-moldable molding compound, for example in the automotive sector. The second type of polymethacrylimide available on an industrial scale is the unsubstituted variant, ie there is no N-alkylation. This is therefore simply referred to as polymethacrylimide (PMI). The production takes place in the casting process, which is why PMI, in contrast to PMMI, has high degrees of polymerization and is no longer meltable. As a highly heat-resistant, creep-resistant foam, PMI is widely used in sandwich constructions in transportation and is available under the trade name ROHACELL ^® . A poly-N-methyl methacrylimide molding composition is produced by a polymer-analogous reaction of a polymethyl methacrylate molding composition with methylamine in an extruder.

Polymethacrylimide foam, on the other hand, is produced in a chamber process. Here, the monomers methacrylic acid and methacrylonitrile are filled with initiators, blowing agents and optionally other additives in a chamber which consists of glass and / or metal plates which are kept at a certain distance with a sealing cord. The closed, filled chamber is immersed in a water bath at a defined temperature, and the copolymer obtained is converted into a polymethacrylimide and heated at the same time in a second step by heating to temperatures between 150 ° C. and 250 ° C. The problem here is that the rate of polymerization of methacrylic acid is significantly higher than that of methacrylonitrile, which is why methacrylic acid reacts preferentially during the polymerization. The result is a heterogeneous polymer chain. Furthermore, the heat removal of the heat of polymerization in the chamber process is difficult. Especially with increasing thickness of the sealing cord (> 20 mm), inadequate heat dissipation or too high a polymerization temperature can lead to an uncontrolled polymerization, which leads to the destruction of the material. The chosen polymerization temperatures must therefore be so low that the duration of the polymerization, depending on the thickness, can be more than one week. The above-described preparation from methacrylic acid and methacrylonitrile also prohibits the substitution of the monomer units on the nitrogen atom of the polymethacrylimide monomer unit. task

It is therefore the task to develop a process for the production of polymethacrylimide foams which ensures sufficient heat dissipation and thus enables the production of large quantities in a short time. Furthermore, the method is intended to ensure the possibility of substitution on the nitrogen atom of the polymethacrylimide monomer unit in order to specifically influence the material properties through the choice of the side chains. Last but not least, monomers are to be reacted in the process which, in contrast to the comonomer pair methacrylic acid / methacrylonitrile, have a comparable reactivity.

In the context of the present invention, therefore, monomers are preferably used which ideally provide statistical copolymers (η = 1, r ₂ = 1, n or r ₂ are the copolymerization parameters) or even tend to alternate copolymers (n; r ₂ = 0) ,

solution

The above-mentioned objects can be achieved by moving away from the bulk polymerization described above to a polymerization in the aqueous phase in the presence of cyclodextrins.

The radical polymerization of monomers in aqueous solutions is of particular technical interest. However, a prerequisite for solution polymerization of the monomers is that the monomers also dissolve in the solvent used in each case. For example, it is not possible to polymerize non-polar monomers in the manner of solution polymerization in water. Water-soluble monomers, such as acrylic acid or maleic acid, are manufactured industrially using the solution polymerization process in water. provides. The copolymerization of, for example, acrylic acid with water-insoluble monomers is therefore not possible in an aqueous medium.

Water-soluble monomers are also radically polymerized using the water-in-oil emulsion polymerization process. However, this method also fails if larger amounts of water-insoluble monomers polymerize in the oil phase, so that virtually no copolymerization occurs.

Even in the bulk polymerization of water-soluble and water-insoluble monomers, it is necessary for the different monomers to be compatible with one another in order to obtain uniform polymers. However, this is not guaranteed for comonomers with very different polarities. In other polymerization techniques, too, such as precipitation polymerization, the incompatibility of water-insoluble monomers with the aqueous media is often a decisive disadvantage.

It is also known from the prior art that cyclodextrins can serve as organic host molecules and are able to take up one or two guest molecules with the formation of supramolecular structures, cf. W. Saenger, Angew. Chem. Int. Ed. Engl. 1980, 19, 344 and G. Wenz, Angew. Chem. Int. Ed. Engl. 1994, 33, 803-822.

It is known from WO 97/09354 that the polymerization of water-insoluble and optionally water-soluble monomers can be carried out by radical polymerization in a diluent. The water-insoluble or at most up to 20 g / l soluble at 20 ° C ethylenically unsaturated monomers are in the form of complexes from a) cyclodextrins and / or cyclodextrin structures containing compounds and b) or c) the ethyl nisch unsaturated monomers in a: (b + c) molar ratio of 1: 1 to 10: 1 or in the presence of up to 5 mol based on 1 mol of monomers (b + c) of cyclodextrin and / or compounds containing cyclodextrin structures polymerized. The molar proportion of cyclodextrin can also be less than 1 in the metering process.

Suitable cyclodextrins are the α-, β-, γ- and δ-cyclodextrins described in the references mentioned above. They are obtained, for example, by enzymatic degradation of starch and consist of 6 to 9 D-glucose units which are linked to one another via an α-1,4-glycosidic bond. α-Cyclodextrin consists of 6 glucose molecules. Compounds containing cyclodextrin structures are to be understood as meaning reaction products of cyclodextrins with reactive compounds, e.g. Reaction products of cyclodextrins with alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide or styrene oxide, reaction products of cyclodextrins with alkylating agents, e.g. Ci to C22 alkyl halides, e.g. Methyl chloride, ethyl chloride, butyl chloride, ethyl bromide, butyl bromide, lauryl chloride, stearyl chloride or behenyl chloride and dimethyl sulfate. A further modification of cyclodextrins is also possible by reaction with chloroacetic acid. Derivatives of cyclodextrins that contain cyclodextrin structures can also be obtained by enzymatic linkage with maltose oligomers. Examples of reaction products of the type specified above are dimethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin and sulfonatopropyl-hydroxypropyl-β-cyclodextrin. Of the compounds of group (a), α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and / or 2,6-dimethyl-β-cyclodextrin are preferably used.

Group b) of the branched alkyl ester methacrylates to be used includes, in addition to tert-butyl methacrylate, for example iso-propyl methacrylate, sec- Butyl methacrylate and longer-chain methacrylates as possible monomers, which preferably contain up to ten carbon atoms in the side chain, which may be branched or not, and where the side chain is to be understood as the alkyl radical which is esterified with methacrylic acid. This also includes the corresponding alkyl ester acrylates. The group b) monomers can be copolymerized with one or more water-insoluble group c) monomers, namely various N-alkyl-substituted methacrylamides. These include, for example, N-octyl methacrylamide, N-nonyl methacrylamide, N-dodecyl methacrylamide, N-methacrylamidocaproic acid, N-methacrylamidoundecanoic acid, N-hydroxyethyl acrylamide and N-hydroxyethylene methacrylamide.

The copolymers are produced by the process described in WO 97/09354. In addition to the N-alkyl-substituted methacrylamides, various methacryloyl derivatives of amino acids are also suitable according to the invention, such as, for example, methacryloylphenylalaninalkyl ester, methacryloyl tyrosinalkyl ester, methacryloylmethioninalkyl ester. The yield of the polymerization can be quantitative or can be varied between 0 and 100% by cooling, adding an initiator or by vigorous dilution.

The chemical and physical properties of the polymers can be varied by copolymerization of the monomers of group (b) and / or (c) with one or more further ethylenically unsaturated monomers of group (b) and / or (c).

By sustainably heating the copolymer to 100-300 ° C., optionally under a nitrogen atmosphere or vacuum, thermal syn-elimination gives isobutene or other volatile elimination products from the tert-butyl ester units or the alkyl ester units. The result is a polymer with imide, anhydride, amide and remaining alkyl ester units. As the reaction time progresses, neighboring amide and carboxylic acid functions react with one another with elimination of water to form imide units.

II

R = -H, -alkyl

In polyalkyl methacrylates with the residues tert-butyl, isopropyl and sec-butyl, thermal elimination is favored over depolymerization. The formation of methacrylic acid and / or methacrylic anhydride units prevents depolymerization and thus degradation to the respective monomers, cf. G.Scott, Polymer Degradation and Stabilization, 1. Polymers and Polymerization, University Press, Cambridge, GB, 1985).

The release of isobutene can also be catalyzed by deprotection of the carboxylic acid by photogenerated acid PAG, cf. Chem. Mater. 1996, 8, 2282-2290.

Elimination can also be carried out by acid hydrolysis, cf. K. Matsumoto et al., J. Polym. Be Part A Polym. Chem. 2001, vol. 39, 86-92. The preparation of polymethacrylimides from methacrylamide copolymers (see IM) by splitting off small molecules has already been described in Macromolecular Chemistry 1966, 96, 227.

IN IV

R = -H, -alkyl

X = -Hai, -O-alkyl, -NH ₂ , -NH-alkyl, -OH

The polymer-analogous reaction of polymethacrylic anhydride with primary amines leads via intermediate III above to polymethacrylimides IV, cf. DBP1165861 (1960) Röhm & Haas GmbH CV.A. 61 (1964) 3231 n and EP926269 (1961) Röhm & Haas GmbH CA. 59 (1963) 10261e.

From US 3,632,797 it is known that by treating polymers with acid or anhydride units with amide, sulfonamide or phosphonamide at 150-250 ° C., polyimides with a high glass transition point can be produced. Polyacrylic acid is dissolved in an acetamide-water mixture and the water is distilled off at 130 ° C. After approximately 3 hours at 190 ° C., polyacrylimides with an imidization degree of 80% are obtained. Polymethacrylimide was synthesized by the same method.

JP 05222262 describes a process for the preparation of polymethacrylimides starting from polymethacrylic anhydride with (fluorinated) aniline at 150-250 ° C. The remaining acid groups are esterified with trimethoxymethane. The polymethacrylic anhydride used here is by Dehydration made by polymethacrylic acid. An imidization level of 50% is achieved.

From J. Pol. Sei., Part A2, Vol. 2. 2385-2400 it is known that PMSA, which was prepared in bulk polymerization or in solution polymerization with hydrocarbons as solvent at temperatures from -50 to 80 ° C, with an excess of aqueous ammonia at room temperature can convert into a poly (methacrylic acid-co-methacrylamide). The thermal decomposition of polymethacrylic anhydride begins at 172 - 175 ° C.

Furthermore, the synthesis of polymethacrylimides starting from polymethyl methacrylates with cyclohexylamine or methylamine in xylene under pressure at 250 ° C. is known in the literature, cf. Macromol. Chem. Phys., 2000, 201, 2826-2837. Molecular weights of around 12,000 g / mol are achieved here.

The authors describe a variant of this synthesis in Macromol. Chem. Phys. 2000, 201, 2838-2844. Here equimolar amounts of methacrylic acid and cyclohexylamine are dissolved in dioxane. The resulting ammonium methacrylate is filtered off and homopolymerized in chloroform with AIBN at 60 ° C. After thermal treatment in xylene at 250 ° C under pressure, the polymer gives a degree of imidization of 35 - 50%. By reacting poly-methyl methacrylate, they achieve an imide content of 40 - 45% and an amide content of 10 - 20% after the same thermal treatment.

The isobutene released by thermal elimination acts as a blowing agent. If the reaction is carried out in a thin layer, the blowing agent diffuses and bubble-free, colorless films are obtained, cf. Angew. Makromol. Chem., II, 1970, 119, 91-108. Foaming of the polymer can only be observed in block form. The thermal conversion of the copolymers produced by means of cyclodextrin in water described here in the context of the present invention has the following advantages over the prior art:

Isobutene is released thermally and at the same time is a foaming agent and therefore does not have to be added, such as urea. To control the pore volume, however, conventional blowing agents such as azodicarbonamide or urea can still be added and the densities of the foams can thus be varied in any way. The amount of blowing agent added is usually 0-20% by weight, but can also be up to 50% by weight.

Organic solvents can be dispensed with in the synthesis of the copolymers. It is an environmentally friendly process. The cyclodextrin used can be recovered.

The reaction can be carried out under normal pressure and without the addition of solvents such as xylene or solvent mixtures such as water / acetamide.

Compared to the known mass process, there is good heat dissipation via the water phase. By complexing the monomers with cyclodextrins in the water phase, the vapor pressure of the monomers is also greatly reduced, which increases occupational safety.

The polymerization of the water-insoluble or at most up to 20 g / l soluble monomers at 20 ° C., such as, for example, tert-butyl methacrylate with a water solubility of 0.34 g / l at 20 ° C., and optionally the water-soluble ones Monomers. such as propyl methacrylamide with a water solubility of 105 g / l at 20 ° C or methacrylamide with a water solubility of 202 g / l at 20 ° C, is carried out in the manner of solution or precipitation polymerization in an aqueous medium, preferably in water. In the present context, aqueous medium is to be understood as meaning mixtures of water and organic liquids which are miscible therewith. Water-miscible organic liquids are, for example, glycols such as ethylene glycol, propylene glycol, block copolymers of ethylene oxide and propylene oxide, alkoxylated C 1 -C ₂₀ -alcohols such as methanol, ethanol, isopropanol and butanol, acetone, tetrahydrofuran, dimethylformamide, N-methylpyrrolidone or else Mixtures of the solvents mentioned. If the polymerization takes place in mixtures of water and water-miscible solvents, the proportion of water-miscible solvents in the mixture is up to 45% by weight. However, the polymerization is preferably carried out in water.

The solution or precipitation polymerization of the monomers is usually carried out with the exclusion of oxygen at temperatures from 10 to 200 ° C., preferably 20 to 140 ° C. The polymerization can be carried out batchwise or continuously. Preferably, at least some of the monomers, initiators and optionally regulators are metered uniformly into the reaction vessel during the polymerization. The monomers and the polymerization initiator can, however, be initially charged and polymerized in the reactor in the case of smaller batches, with the heat of polymerization having to be adequately rapidly removed, if necessary, by cooling.

Possible polymerization initiators are the compounds customarily used in free-radical polymerizations which give free radicals under the polymerization conditions, such as, for example, peroxides, hydroperoxides, peroxodisulfates, percarbonates, peroxiesters, hydrogen peroxide and azo compounds. Examples of initiators are hydrogen peroxide, dibenzoyl peroxide, dicyclohexyl peroxodicarbonate, dilauryl peroxide, methyl ethyl ketone peroxide, acetylacetone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butyl perneodecanoate, tert-amyl perpivalate, sodium, butyl perpylate, sodium butyl perpylate Potassium and ammonium peroxodisulfate, azoisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2- (carbamoylazo) isobutyronitrile and 4,4'-azobis (cyanovaleric acid). The initiators are usually used in amounts of up to 15, preferably 0.02 to 10% by weight, based on the monomers to be polymerized.

The initiators can be used alone or as a mixture with one another. The use of the known redox catalysts, in which the reducing component is used in molar deficit, are also suitable. Known redox catalysts are, for example, salts of transition metals such as iron-II-sulfate, copper-I-chloride, manganese-II-acetate, vanadium-III-acetate. Further redox catalysts include reducing sulfur compounds, such as sulfites, bisulfites, thiosulfates, dithionites and tetrathionates of alkali metals and ammonium compounds, or reducing phosphorus compounds in which the phosphorus has an oxidation number of 1 to 4, such as sodium hypophosphite, phosphorous acid and phosphites consideration.

In order to control the molecular weight of the polymers, the polymerization can optionally be carried out in the presence of regulators. Suitable regulators are, for example, aldehydes such as formaldehyde, acetaldehyde, propional dehyde, n-butyraldehyde and isobutyraldehyde, formic acid, ammonium formate, hydroxylammonium sulfate and hydroxylammonium phosphate. It is also possible to use regulators which contain sulfur in organically bound form, such as organic compounds having SH groups, such as thioglycols. acetic acid, mercaptopropionic acid, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptohexanol, dodecyl mercaptan and tert-dodecyl mercaptan. Salts of hydrazine such as hydrazinium sulfate can also be used as regulators. The amounts of regulator, based on the monomers to be polymerized, are 0 to 20, preferably 0.5 to 15% by weight.

If the water-insoluble or slightly water-soluble monomers are not introduced into the reactor in the form of complexes of cyclodextrins and water-insoluble or slightly water-soluble monomers from group (b, c) during the polymerization, the water-insoluble or slightly water-soluble monomers (b, c) meter in compounds contained in an aqueous solution of cyclodextrins and / or cyclodextrin structures and subject to the polymerization in the presence of polymerization initiators and optionally regulators. Host / guest complexes are formed in the reaction medium from the water-insoluble or slightly water-soluble monomers (b, c) and the cyclodextrins and / or cyclodextrin structures present therein, which permit the production of uniform homo- and copolymers. The cyclodextrins can also form host / guest complexes with water soluble monomers.

The products produced by the process according to the invention are suitable for the production of foams and general molding compositions.

Examples

Copolymerization in the presence of 2,6-dimethyl-ß-cyclodextrin (Me-ß-CD)

The copolymers were analyzed using IR and NMR. The molecular weights were analyzed by SEC. The measurements were carried out using a PSS system with dimethylformamide as the eluent at 25 ° C. Polystyrene standards were used for the calibration (374 to 1,000

000 D). At a flow rate of 1 ml / min, 150 / l of a 0.125% by weight polymer solution in dimethylformamide were placed on a column system which consists of a HEMA column combination with a particle size of 10 μ (precolumn porosity 40 Å, analytical column porosities of 40, 100 and 3000 Ä). The signals were detected using a UV-VIS detector (TSP UV2000, 254 nm) and a differential refractometer (Shodex RI-71) against toluene as the internal standard. The evaluation was carried out using the software PSS-WinGPC 4.01 or 6.1.

example 1

0.95 g of N-octyl methacrylamide and 0.68 g of tert-butyl methacrylate were dissolved in 63 mL of a degassed 30% by weight solution of Me-ß-CD in deionized

Dissolved water (monomers: Me-ß-CD 1: 1, 5) and at room temperature (25 ° C)

Stirred for 1 h under nitrogen. The clear reaction solution was heated to 50 ° C under nitrogen. A solution of 0.1552 g of 2,2'-azobis (2-amidinopropane) dihydrochloride was weighed out and dissolved in deionized water. Now 1 mL of the initiator solution was pipetted into the reaction solution so that the initiator concentration based on the monomers was 1 mol%. The solution became cloudy after 1.5 minutes as a result of the precipitation polymerization. To

The polymer was separated off and dried for 2 hours. The copolymer was obtained in a yield of 24%. According to elemental analysis, the amide was also installed a share of 0.47. The weight average molecular weight M _w was 62,900 g / mol, the number average molecular weight M _n 26,300 g / mol and the polydispersity was 2.39.

Example 2

0.95 g of N-octyl methacrylamide and 0.68 g of tert-butyl methacrylate were dissolved in 126 mL of a degassed 30% by weight solution of Me-ß-CD in deionized water (monomers: Me-ß-CD 1: 3) and stirred at room temperature (25 ° C) for 1 h under nitrogen. 0.1298 g of potassium peroxodisulfate (K ₂ S ₂ 0 ₈ ) and 0.0913 g of sodium pyrosulfite (Na S 0 ₅ ) were weighed out and dissolved in deionized water. 1 mL each of the initiator solutions were pipetted into the reaction solution, so that the initiator concentration based on the monomers was 1 mol%. The solution became cloudy after only 1 min as a result of the precipitation polymerization. After 2 hours, the polymer was separated off and dried. The copolymer was obtained in a yield of 57%. According to elemental analysis, the amide was incorporated with a share of 0.44. The weight average molecular weight M _w was 66 800 g / mol, the number average molecular weight M _n 26 200 g / mol and the polydispersity 2.55.

Example 3

The preparation and polymerization were carried out analogously to Example 1. The polymerization was stopped after 75 h. The copolymer was obtained in a yield of 22%. According to elemental analysis, the amide was incorporated with a share of 0.49. The weight average molecular weight M _w was 59,300 g / mol, the number average molecular weight M _n 28,400 g / mol and the polydispersity was 2.09. Example 4

The preparation and polymerization were carried out analogously to Example 1. However, potassium peroxodisulfate was used as the initiator. The copolymerization was stopped after 3 h 20 min. The copolymer was obtained in a yield of 51%. According to elemental analysis, the amide was incorporated with a share of 0.57. The weight average molecular weight M _w was 33,000 g / mol, the number average molecular weight M _n 14,000 g / mol and the polydispersity was 2.35.

Example 5

The preparation and polymerization were carried out analogously to Example 4. However, 9.47 g of N-octyl methacrylamide and 6.83 g of tert-butyl methacrylate were dissolved in 630 ml of a degassed 30% by weight solution of Me-β-CD in deionized water. The copolymerization was stopped after 3 h 20 min. The copolymer was obtained in a yield of 56%. According to elemental analysis, the amide was incorporated with a share of 0.55. The weight average molecular weight M _w was 328 200 g / mol, the number average molecular weight M _n 65 600 g / mol and the polydispersity 5.00.

Example 6

63 mL of a degassed 30% by weight solution of Me-ß-CD in deionized water (monomers: Me-ß-CD 1: 1, 5) were placed in a 250 mL three-necked flask. The cyclodextrin solution was heated to 50 ° C under nitrogen. The initiator solutions were prepared and added as in Example 2. 0.95 g of N-octyl methacrylamide and 0.68 g of tert-butyl methacrylate were added dropwise from a dropping funnel. The solution became cloudy after only 1 min as a result of the precipitation polymerization. After 2 h 55 min, the polymer was separated off and dried. The copolymer was obtained in a yield of 58%. According to elemental analysis, the amide was also installed a share of 0.51. The weight average molecular weight M _w was 42 100 g / mol, the number average molecular weight M _n 13 900 g / mol and the polydispersity 3.03.

Example 7

Analogously to Example 4, 0.54 g of N-ethyl methacrylamide and 0.68 g of tert-butyl methacrylate were used. After 4 hours, the polymer was separated off and dried. The copolymer was obtained in a yield of 63%. According to elemental analysis, the amide was incorporated with a share of 0.45. The weight average molecular weight M _w was 16 100 g / mol, the number average molecular weight M _n 8 700 g / mol and the polydispersity 1.87.

Example 8

Analogously to Example 4, 0.84 g of N-benzyl methacrylamide and 0.68 g of tert-butyl methacrylate were used. After 3 hours, the polymer was separated off and dried. The copolymer was obtained in a yield of 67%. According to elemental analysis, the amide was incorporated with a proportion of 0.29. The weight average molecular weight M _w was 60400 g / mol, the number average molecular weight M _n 13 200 g / mol and the polydispersity 4.57.

Example 9

Analogously to Example 4, 0.80 g of N-cyclohexyl methacrylamide and 0.68 g of tert-butyl methacrylate were used. After 3 hours, the polymer was separated off and dried. The copolymer was obtained in a yield of 50%. According to elemental analysis, the amide was incorporated with a proportion of 0.29. The weight average molecular weight M _w was 50 200 g / mol, the number average molecular weight M _n 14 000 g / mol and the polydispersity 3.60.

Example 10 5.02 g of tert-butyl methacrylate were dissolved in 420 ml of a degassed 30% by weight solution of Me-β-CD in deionized water and stirred at room temperature (25 ° C.) for 15 minutes under nitrogen. 4.00 g of N-ethyl methacrylamide were then added with stirring (monomers: Me-β-CD 1: 1). 0.1910 g of potassium peroxodisulfate (K ₂ S ₂ 08) and 0.1343 g of sodium pyrosulfite (Na ₂ S ₂ 0 ₅ ) were weighed out and dissolved in deionized water. 1 mL each of the initiator solutions were pipetted into the reaction solution, so that the initiator concentration based on the monomers was 1 mol%. The solution became cloudy after 1.5 minutes as a result of the precipitation polymerization. After 4 hours, the polymer was separated off and dried. The copolymer was obtained in a yield of 84%. According to elemental analysis, the amide was incorporated with a share of 0.43. The weight average molecular weight M _w was 87 500 g / mol, the number average molecular weight M _n 21 900 g / mol and the polydispersity was 3.99.

Thermolysis of the copolymers

With the help of a press, the polymers were produced within 6 min at a pressure of 10 bar. These were heated in an autoclave at a pressure of 1 bar nitrogen. The polymer products could be identified as imides by means of NMR and IR.

Example 11

The thermolysis of a sample of poly (tert-butyl methacrylate-co-octyl methacrylamide) at 260 ° C. for 3 hours led to a brown-colored product with a pore structure. The mass loss was 33%. The degree of imidization determined from the elemental analysis was 85%. The weight average molecular weight M _w was 126,000 g / mol, the number average molecular weight M _n 31 200 g / mol and the polydispersity 4.03. Example 12

The thermolysis of a sample of poly (tert-butyl methacrylate-co-ethyl methacrylamide) at 250 ° C. for 1.5 hours led to a light brown colored product with a pore structure. The mass loss was 47%. The degree of imidization determined from the elemental analysis was 79%. The weight average molecular weight M _w was 18 700 g / mol, the number average molecular weight M _n 8 500 g / mol and the polydispersity was 2.19.

Example 13

The thermolysis of a sample of poly (tert-butyl methacrylate-co-benzyl methacrylamide) at 260 ° C. for 2 h 25 min led to a brown-colored product with a pore structure. The degree of imidization determined from the elemental analysis was 61%. The weight average molecular weight M _w was 105 100 g / mol, the number average molecular weight M _n 14 000 g / mol and the polydispersity 7.54.

Example 14

The thermolysis of a sample of poly (tert-butyl methacrylate-co-cyclohexyl methacrylamide) at 260 ° C. for 2 h 25 min led to a yellow-colored product. For a fully imidized product, the nitrogen content determined by elemental analysis should be 6.27. The degree of imidization determined from the elemental analysis was 51%. The weight average molecular weight M _w was 88 700 g / mol, the number average molecular weight M _n 15 200 g / mol and the polydispersity was 5.82.

Example 15

The thermolysis of a sample of poly (tert-butyl methacrylate-co-cyclohexyl methacrylamide) at 220 ° C. for a period of 245 min led to a yellow-colored product with a pore structure. The mass loss was 12 %. The degree of imidization determined from the elemental analysis was 44%. The weight average molecular weight M _w was 41 500 g / mol, the number average molecular weight M _n 10 100 g / mol and the polydispersity 4.09. The density of the foam obtained was determined to be 137 kg / m ³ .

Example 16

The thermolysis of a sample of poly (tert-butyl methacrylate-co-ethyl methacrylamide) at 240 ° C. for a period of 141 min led to a light brown colored product with a pore structure. The mass loss was 35%. According to IR, the end product contains no anhydride functions and only a small amount of amide. The degree of imidization determined from NMR measurements was 79%. The weight average molecular weight M _w was 67 400 g / mol, the number average molecular weight M _n 18 300 g / mol and the polydispersity 3.68. The density of the foam obtained was determined to be 306 kg / m ³ .

Example 17

The thermolysis of a sample of poly (tert-butyl methacrylate-co-ethyl methacrylamide) at 250 ° C. for 182 min led to a dark brown colored product with a pore structure. The mass loss was 40%. According to IR, the end product contains small amounts of anhydride and amide. The degree of imidization determined from NMR measurements was 75%. The weight average molecular weight M _w was 97,900 g / mol, the number average molecular weight M _n 18,700 g / mol and the polydispersity was 5.23. The density of the foam obtained was determined to be 260 kg / m ³ .

Example 18

The thermolysis of a sample of poly (tert-butyl methacrylate-co-ethyl methacrylamide) at 250 ° C. for 309 minutes resulted in a dark brown colored product with a pore structure. The mass loss was 29 %. The degree of imidization determined from NMR measurements was 71%. The weight average molecular weight M _w was 74,900 g / mol, the number average molecular weight M _n 19,600 g / mol and the polydispersity was 3.82.

In the following examples, the compacts were thermolyzed at 250 ° C. in a foam cabinet.

Example 19

The thermolysis of a sample of poly (tert-butyl methacrylate-co-ethyl methacrylamide) at 250 ° C. for 15 minutes resulted in a light brown colored product. The mass loss was 30%. The degree of imidization determined from the elemental analysis was 75%. The weight average molecular weight M _w was 14,800 g / mol, the number average molecular weight M _n 6,800 g / mol and the polydispersity was 2.17.

Example 20

The thermolysis of a sample of poly (tert-butyl methacrylate-co-benzyl methacrylamide) at 250 ° C. for 15 minutes led to a dark brown colored product. The mass loss was 38%. The degree of imidization determined from the elemental analysis was 57%. The weight average molecular weight M _w was 63 800 g / mol, the number average molecular weight M _n 14 000 g / mol and the polydispersity 4.57.

Comparative Example 1:

330 g of isopropanol and 100 g of formamide were added as blowing agents to a mixture of 5700 g of methacrylic acid, 4380 g of methacrylonitrile and 31 g of allyl methacrylate. In addition, 4 g of tert-butyl perpivalate, 3.2 g of tert-butyl per-2-ethyl hexanoate, 10 g of tert-butyl perbenzoate, 10.3 g of cumyl perneo- decanoate, 22g magnesium oxide, 15g release agent (PAT 1037) and 0.07g hydroquinone added.

This mixture was polymerized for 68 hours at 40 ° C. and in a chamber formed from two glass plates measuring 50 × 50 cm and an 18.5 mm thick edge seal. The polymer was then subjected to an annealing program ranging from 32 ° C. to 115 ° C. for 32 hours for the final polymerization. The subsequent foaming took place at 205 ° C. for 2 h 25 min. The foam thus obtained had a density of 235 kg / m ³ .

Comparative Example 2:

A foam with a density of 71 kg / m ³ was produced in accordance with DE 33 46 060, 10 parts by weight of DMMP being used as the flame retardant.

For this purpose, 140 g of formamide and 135 g of water were added as a blowing agent to a mixture of equal molar parts of 5620 g of methacrylic acid and 4380 g of methacrylonitrile. 10.0 g of tert-butyl perbenzoate, 4.0 g of tert-butyl perpivalate, 3.0 g of tert-butyl per-2-ethylhexanoate and 10.0 g of cumyl perneodecanoate were also added to the mixture as initiators. In addition, 1000 g of dimethyl methane phosphonate (DMMP) were added to the mixture as a flame retardant. Finally, the mixture contained 20g release agent (MoldWiz) and 70g ZnO and 0.07g hydroquinone.

This mixture was polymerized for 92 hours at 40 ° C. in a chamber formed from two glass plates of size 50 * 50 cm and a 2.2 cm thick edge seal. The polymer was then subjected to a tempering program ranging from 40 ° C. to 115 ° C. for 17.25 hours. The subsequent foaming took place at 215 ° C. for 2 hours. The foam thus obtained had a density of 71 kg / m ³ . Comparative Example 3

For this purpose, a mixture of 5700 g methacrylic acid and 4300 g methacrylonitrile, 140 g formamide and 135 g water were added as blowing agents. Furthermore, 10.0 g of tert-butyl perbenzoate, 4.0 g of tert-butyl perpivalate, 3.0 g of tert-butyl per-2-ethylhexanoate and 10 g of cumyl perneodecanoate were added to the mixture as initiators. In addition, 1000 g of dimethyl methane phosphonate (DMMP) were added to the mixture as a flame retardant. Finally, the mixture contained 15 g of release agent (PAT) and 70 g of ZnO and 0.07 g of hydroquinone. This mixture was polymerized for 92 hours at 40 ° C. in a chamber formed from two glass plates of size 50 * 50 cm and a 2.2 cm thick edge seal. The polymer was then subjected to a tempering program ranging from 40 ° C. to 115 ° C. for 17.25 hours. The subsequent foaming took place at 220 ° C. for 2 hours. The foam thus obtained had a density of 51 kg / m ³ .

Comparative Example 4

The procedure was essentially as in the case of Comparative Example 2, except that the foaming took place at 210 ° C. and the density of the foam obtained was then 110 kg / m ³ .

Claims

claims

1. Process for the preparation of polymers from slightly water-soluble monomers and possibly water-insoluble monomers by radical polymerization of the monomers in a diluent

characterized in that

the polymerization is carried out in water as a diluent and the monomers are in the form of complexes composed of cyclodextrins and / or cyclodextrin structures and water-insoluble or at most up to 20 g / l of water-soluble ethylenically unsaturated monomers at 20 ° C. in a: b molar ratio of 1:10 up to 10: 1 is used or the monomers are polymerized in the presence of up to 10 mol based on 1 mol of the sum of monomers a + b of compounds containing cyclodextrins and / or cyclodextrin structure and converted to polymethacrylimides by thermolysis.

Process for the preparation of polymers from slightly water-soluble monomers and possibly water-insoluble monomers by radical polymerization of the monomers in a diluent

characterized in that

one carries out the polymerization in water as a diluent and the monomers in the form of complexes of cyclodextrins and / or compounds containing cyclodextrin structures and water-insoluble or at most up to 20 g / l at 20 ° C water-soluble ethylenically unsaturated monomers in a: b molar ratio of 1: 5 to 5: 1 or the monomers in the presence of up to 5 mol based on 1 mol of the sum of the monomers a + b polymerized on compounds containing cyclodextrins and / or cyclodextrin structure and converted to polymethacrylimides by thermolysis.

3. Process for the preparation of polymers from slightly water-soluble monomers and possibly water-insoluble monomers by radical polymerization of the monomers in a diluent

characterized in that

the polymerization is carried out in water as a diluent and the monomers in the form of complexes of cyclodextrins and / or cyclodextrin structures containing compounds and water-insoluble or at most up to 20 g / l at 20 ° C. water-soluble ethylenically unsaturated monomers in a: b molar ratio of 1: 2 up to 2: 1 is used or the monomers are polymerized in the presence of up to 5 mol based on 1 mol of the sum of the monomers a + b of compounds containing cyclodextrins and / or cyclodextrin structure and converted to polymethacrylimides by thermolysis.

4. The method according to claim 1 to 3,

characterized in that

one uses as a cyclodextrin and / or cyclodextrin-containing component α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and / or 2,6-dimethyl-β-cyclodextrin.

5. The method according to claim 1 to 3,

characterized in that

one uses as the component containing cyclodextrin and / or cyclodextrin 2,6-dimethyl-β-cyclodextrin.

Process according to claims 1 to 5, wherein tert-butyl methacrylate is used as monomer (a).

Process according to claims 1 to 5,

characterized in that

the monomer (b) used is N-alkyl-substituted methacrylamides or methacryloyl derivatives of the amino acids.

8. The method according to claims 1 to 5, wherein the monomer (a) is tert-butyl methacrylate and the monomer (b) is N-alkyl-substituted methacrylamides or methacryloyl derivatives of the amino acids.

Process for the preparation of substituted polymethacrylimides by thermolysis of polymers prepared by one of the processes described in claims 1 to 8 in such a way that the polymers are aminolyzed by heating to structure II.

10. A process for the preparation of substituted polymethacrylimides by thermolysis of polymers prepared by one of the processes described in claims 1 to 8 in such a way that the polymers are aminolyzed by heating to structure II and foamed by splitting off gaseous reaction products.

11. Use of the optionally substituted polymethacrylimides obtainable according to claims 1 to 10 for the production of general molding compositions

12. Use of the optionally substituted polymethacrylimides obtainable according to claims 1 to 11 for the production of foams.

13. Use of the general molding compositions obtainable according to claim 11 for the production of foams.

14. Use of the substituted polymethacrylimides obtainable according to claims 1 to 10 for the use or production of coating compositions.

15. Use of the substituted polymethacrylimides obtainable according to claims 1 to 11 for the use or production of membrane materials.

16. Use of the foams mentioned in claims 10, 12 and 13 in sandwich constructions.