NO160036B - MAGNETIC POLYMER PARTICLES AND PROCEDURES FOR PRODUCING THEREOF. - Google Patents

Description

The present invention relates to magnetic polymer particles and a method for their production. Magnetic polymer particles have been tried and used in a number of areas in biochemistry and in medicine. They have been tried to be used as carriers of medical preparations because, with the help of their magnetic properties, they can transport the preparations to the desired place in the body. Magnetic particles also have other practical applications and have been used in diagnostics as the separation of particles by centrifugation can be replaced by the far easier method of magnetic extraction. Magnetic particles have also been used for cell separation and as carriers of enzymes. Of more technical applications can be mentioned as toners in copying technology.

Previous methods for producing particles with e.g. magnetic iron oxide (magnetite) has evolved from magnetite Fe^Oj. People have tried in various ways to

thereby coating the magnetite particles with polymeric material

to obtain polymer particles containing magnetite.

A widely used method makes use of magnetite powder which is mechanically mixed with molten polymer. After this treatment, the polymeric material containing magnetite is crushed. This results in particles of uneven shape and of very different sizes. Particles produced in this way are often used as toners,

but the uneven shape is undesirable as it gives uneven and flowing edges to the writing.

Another method makes use of finely divided magnetite to which vinyl monomer and initiator are added to water, whereby a polymer is formed around the magnetite grains. This also produces magnetic particles of undefined and highly varying size and shape. Moreover, only a portion of the particles become magnetic,

and the content of magnetite in the particles is usually very uneven. Other methods describe mixing albumin and other proteins

with magnetite and vigorous stirring in water with an emulsifier to form droplets containing magnetite and protein. Another method involves treating swelling polymer particles with finely divided magnetite and getting magnetite on and possibly some into the particles.

The fact that magnetite is used will, even if it is used in very finely divided form, place great limitations on the type and size of the particles. Any real diffusion of molecular material into the particles or into pores in the particles will not take place. With solid, porous particles, you had to have very large pores and therefore large particles so that magnetite grains do not just sit on the surface of the particles. With highly swelling particles, you can get some magnetite into the particles mechanically, but the magnetite will essentially remain on the surface and give a very uneven surface.

In the method according to the present invention, iron is introduced into the particles in the form of salts and then transferred to magnetic iron oxide, which will largely be magnetite (Fe^O^) or oxides with similar magnetism.

For many of the above-mentioned purposes, the particles produced according to the invention will be advantageous because they are spherical and have a uniform concentration of magnetic material which can be varied as desired within wide limits. In particular, the method enables the production of monodisperse particles of the desired size, both compact and porous.

The method according to the present invention is suitable for both compact and porous polymer particles and can be used for the production of magnetic polymer particles of all sizes. In particular, the method is suitable for the production of particles in the range 0.5-20 mhi, but can also be used for the production of particles smaller than 0.5 nm and larger than 20 µm in diameter. A major advantage of the method is that it allows all the particles to have the same concentration of magnetic iron oxide. Quite particularly, the method using starting material of monodisperse polymer particles will produce monodisperse, magnetic polymer particles that all contain the same amount of magnetic iron oxide.

According to the invention, a method for the production of magnetic polymer particles is provided. The method is characterized by the fact that solutions of iron salts and possibly salts of other metals which can form magnetic ferrites,

in water or in a mixture of water and water-soluble organic solvents or in organic solvents, mixed with polymer particles in dry form or dispersed in water or in a mixture of water and water-soluble organic liquids or in organic liquids, and the metals are precipitated in the form of hydroxides, e.g. by raising the pH value, and possibly heating the particles.

In the following description of the new method

for the production of magnetic polymer particles, the production of magnetic particles with magnetite Fe^O^, which can also be described as ferroferrite, FeFejO^, is described in detail.

As will be seen, some of the described embodiments can also be used for the production of polymer particles with other magnetic ferrites such as manganese ferrite MnFe20^, cobalt ferrite CoFe204 and nickel ferrite NiFe2<0>4. Normally, the content of magnetic ferrite in the particles will be over 5%.

According to the invention, particularly compact or porous particles are used which contain groups which could lead to the iron salt being drawn into the particles and possibly bound there. These groups can be introduced into the particles by producing polymer from monomers containing these groups. Examples of monomers which have proved particularly suitable are dimethylaminoethyl methacrylate, N-(dimethylaminopropyl) methacrylamide and vinylpyridine which will bind the iron salts with a coordinative bond. Other examples of suitable monomers are those containing ethylene oxide groups (-CH2-CH2-0-) or alkylenimine groups (-CH2-CHR'-NH-, where R' = H or alkyl).

One can also bind the iron with ionic bonds. In that one

on and in the particles have acid groups, the iron will be able to be transported from the outer phase of dissolved iron salt and bind to these groups. Examples of monomers which will give such acid groups are methacrylic acid, p-vinylbenzoic acid and maleic anhydride. The iron salt-binding groups can further be introduced on ready-made polymers.

Thus, a copolymer can be produced from a monomer mixture which for the most part consists of vinyl monomer with epoxy group(s) such as e.g. glycidyl methacrylate:

By treating the finished polymer with substances that react with epoxy groups and that contain N groups, you will get these groups covalently bound on and in the particles. For example, one can treat polymer particles containing epoxy groups with ethylene diamine and get -CH2-NH-CH2-CH2-NH2 groups formed, or with ethylene epoxy group-containing substances such as NH2-R- (CH2CH20)nR' or HOOCRCOO(C<H>2 <CH>20)nR' where R is a suitable aliphatic or aromatic group. R' is hydrogen or alkyl, and n is an integer from 1 to 500, to introduce -(CH2-C<H>2-0)nR' groups. For the introduction of -(CH2-CHR<*>-NH-)nH groups one can e.g. react polymer particles containing -COOH groups with alkylenimine compounds, whereby -CO-O-(CH2-CHR'-NH-)nH groups are formed. For the introduction of amino and/or imino groups, if the polymer contains ester groups such as -C00R' where R' is an alkyl group, an aminolysis can be carried out with an organic amine containing more than one amino group. For example, during aminolysis of a polymer with -C00R' groups with diethylenetriamine, -C0NH-CH2CH2NHCH2CH2N<H>2 will be formed. These reactions can also lead to the particles becoming more hydrophilic and will swell with H20 so that iron salts are bound inside the particles.

Another method for introducing iron-binding groups includes the introduction of -NH2 groups or -CH2-NH2 groups on the benzene core in polymer particles produced by polymerization of monomers that substantially contain benzene rings such as styrene and divinylbenzene.

Furthermore, after introducing -CH2NH2 onto the benzene nucleus, (CH-CH-O) R' groups can be introduced by reaction with

where R' and n are as above.

One can also introduce CH2C1 groups on the benzene nucleus and react these groups with HO(CH2CH20)nR<*> or

NH2(CH2CH2NH)n<N>H2.

The ethylene oxide chain can also be introduced into the finished polymer by reacting such a polymer containing acid groups with

the epoxy

On polymers containing benzene cores, -NH-NH2 groups can be introduced on the benzene core. If you treat particles made from acrylates with hydrazine, -CONH-NH2 groups are formed.

Likewise, acid groups can be introduced onto finished polymer particles. This can, for example, be done by hydrolysing a polymer containing ester groups. Similarly, by known methods, sulphonic acid groups and carboxylic acid groups can be introduced onto the polymer which is made from styrene and/or styrene derivatives and mixed with divinylbenzene.

By

a) production of a polymer from a monomer containing N groups, hydroxy, ethylene oxide or acid groups,

by

b) post-treatment of a polymer containing epoxy groups with substances such as ethylenediamine,

by

c) post-treatment of polymer containing carboxylic acid groups with alkylenimine,

by

d) post-treatment of a polymer containing ester groups with an organic amine having more than one -NH2 or -NH- group,

and likewise wood

e) post-treatment of acrylate particles with hydrazine,

will you be able to get particles that swell in water or mixture

of water and organic solvents, which will facilitate the introduction of iron salt into the particles and lead to more iron salt being bound. The polymer particles can also be produced as porous particles with a macroreticular structure, i.e. with a fixed pore structure. In this case, the iron salts will be able to bind in a single layer to the surface inside the pores, but as this surface is very large, one will still

could get a relatively high content of iron inside the particles. In other cases, the iron compound will be able to fill the pores to a greater or lesser extent. Porous particles with a macroreticular structure can be produced with groups that directly bind iron salts, or the particles can be post-treated to introduce these groups as described above.

If you have porous particles with a large surface area, you can also get iron salt introduced into the particles by coating the inner surface with substances that contain iron-binding groups and which bind very strongly to the surface before adding iron salts, or you add this substance together with the iron salt . Such substances are e.g. polyamine amide with limited chain length or substances containing one or preferably several acid groups or acid groups combined with other groups that give strong binding of iron salts.

With porous particles, you can use iron salts where the anionic group is so large and is so hydrophobic that it binds directly to the inner surface by physical adsorption.

After mixing the particles and iron salts, the pH is raised and iron hydroxide is formed. In case you have groups that bind iron salts and these are primary, secondary or tertiary amines, polyethylene oxide groups or anions of acids, you will preferably add a mixture of a divalent and trivalent salt in a ratio that will give an amount of Fe(OH)2 and Fe(OH)3 after precipitation, which corresponds to the fact that from this mixture you will be able to get magnetite Fe304- It is then a special and important point that the particles

contains groups that pull the iron salt from the outer phase and bind this on and inside the particles so that when the pH is raised, there is no significant precipitation of Fe(OH)3 in the outer phase outside the particles.

If one in particles that are swollen by the liquid in the outer

phase or in porous particles that are filled by the liquid in the outer phase, do not have groups that bind iron salts, only a part of the iron salt will be found inside the particles, and when the pH is raised, a significant part of added trivalent iron salt would be precipitated in the outer phase, which would mean that both less magnetic iron oxide was formed in the particles and likewise a significant amount of magnetic iron oxide would be obtained in the outer phase with attendant difficult cleaning processes.

In certain cases where you have particles made with a certain proportion of polyvinyl monomer (i.e. a monomer with several vinyl groups, e.g. divinylbenzene), you can swell the particles in organic solvents and iron salts that are soluble in these can then be introduced the solvents. In this case too, it is an advantage that the particles have groups that will bind the iron salts so that when the particles are subsequently transferred to water, you will achieve that the iron salts remain bound inside the particles. In the case of using iron salts with hydrophobic anions, e.g. iron laurate, the iron compounds will remain in the particles when these are transferred to water, and special iron-binding groups are not of the same importance. This will also be the case where solid porous particles with a hydrophobic structure are used.

If the iron-binding groups are hydrazine groups -NH-NH2, a trivalent iron salt will preferably be used. In this case too, it is therefore important that the trivalent iron salt is bound on and in the particles before the pH is raised and Fe(OH)3 is formed.

In a particular embodiment of the present invention, porous particles are produced which contain N02 groups bound to the benzene cores. These particles can e.g. can be produced by producing porous particles from nitrostyrene and divinylbenzene in the usual way, i.e. in the presence of inert solvents which are removed after polymerization, or you can produce porous particles from styrene or styrene derivatives and divinylbenzene and then introduce heat groups on the benzene groups according to usual methods.

In these cases where you have nitro groups inside porous particles, you use exclusively divalent iron salt. The nitro groups will only to a small extent lead to the iron salt being transported from the outer phase into the particles. However, when the pH is increased and Fe(OH)2 is formed, an oxidation will take place inside the particles with the help of -N02 groups which will oxidize Fe(OH)2 to Fe(OH)3 in an amount so that the ratio between two- and trivalent iron corresponds to that in Fe^O^. Thereby, more and more Fe(OH)2 is transferred from the outer phase to the pores in the particles. This process is accelerated by the fact that oxidation of Fe(OH)2 with -N02 groups leads to the -N02 groups being transferred to groups where the nitrogen has a higher electron density and thereby has an increased ability to bind iron salt.

The same principle, i.e. oxidation of added 2-valent iron salt with an oxidizing nitro compound, can also be carried out

when the oxidizing nitro compounds are -0N02 groups or ONO groups.

These groups can e.g. advantageously introduced on porous particles that contain a large number of hydroxy groups on the surface by reacting these with HNO^ or HN02<

Examples of such polymers are macroreticular porous particles produced with a substantial part of hydroxyethyl methacrylate in the monomer mixture. Other examples are porous particles with a significant content of glycidyl methacrylate in the monomer mixture. In this case, you will be able to react

the epoxy groups

directly with HNO^ or HN02 or Mon

can introduce hydroxy groups by reaction of epoxy groups with e.g. aminoethanol.

By the methods that include Fe(OH)2 being formed

and Fe(OH)3 on and in the particles, one will often find that the particles have become magnetic already directly upon the formation of this mixture. A more complete magnetization with the formation of Fe^O^ is obtained by heating. It is usually sufficient to heat the particles in aqueous dispersion to temperatures below 100°C. The particles can be isolated by centrifugation or filtration or extracted with a magnet and dried, and can optionally also be heated in a dry state.

In the event that hydrazine groups are used, pure trivalent salt can be used and Fe(OH)3 is then formed which, with the help of

the hydrazine groups are reduced to a mixture of divalent and trivalent iron corresponding to an oxidation step as in magnetite. This is preferably done at temperatures above 100°C.

If, according to one of the above methods, you have obtained

formed either divalent or trivalent iron hydroxide in or on the particles, it will also be possible to transfer the hydroxide to the desired mixture of divalent and trivalent iron hydroxide. Divalent iron hydroxide can e.g. oxidized by adding a suitable oxidation agent1, e.g. nitration or an organic nitro compound, or the oxidation can e.g. take place by blowing through oxygen. Trivalent iron hydroxide can be reduced with a suitable reducing agent, e.g. hydrazine.

In magnetite, Fe^O^, the ratio of divalent and trivalent iron is 1:2. It is therefore appropriate to use a mixture of iron salts with approximately this ratio between divalent and trivalent salts when there are no normally reducing/oxidizing groups present. If the ratio Fe<++>/Fe<+++> after raising the pH is significantly above 1:2, it is oxidized, and if it is significantly below 1:2, the formed hydroxides are reduced to

get magnetic iron oxide formed.

In the methods described above, where a mixture of 2- and 3-valent iron salt or a 2-valent iron salt that is oxidized was used, ferroferrites (FeFe204 Fe304) are produced. In these cases, a mixture can also be used

of iron salts with other metal salts which will give other types of magnetic ferrites. Thus, by the same principles, manganese ferrite, MnFe204, cobalt ferrite, CoFe204 or nickel ferrite NiFe204 can be formed. In the event that one is used

mixture of a water-soluble salt of a divalent metal,

such as MnX n , CoX n or NiX n. where X is a 2/n-valent anion (n = 2, 1, 2/3 or 1/2, especially 1 or 2) and a water-soluble salt of 3-valent iron becomes the salt mixtures precipitate as hydroxides inside the particles and are then heated to the appropriate temperature, whereby the corresponding magnetic metal ferrites are formed. In the event that a salt of divalent iron is used in mixture with the other metal salt, the divalent iron in the form of iron hydroxide inside the particles is oxidized to trivalent iron under conditions which give the desired metal ferrite. The oxidation can take place by oxidizing groups such as -NOj, -ONO or -0N02 which are introduced on the polymer, or it can take place by adding suitable oxidizing agents. In this case, you will be able to get a mixture of ferroferrite with other ferrites, MeFe20^, where Me stands for Co, Ni or Mn. An advantage of using a mixture of iron salt with other metal salts is that in this case there is no risk of any overoxidation of the iron, since in that case only MeFejO^ is formed at the expense of FeFe2O4.

The polymeric particles used as starting material

for the production of the magnetic particles, can in principle be produced according to all the methods that are known for the production of dispersions of polymeric particles. This includes production by ordinary emulsion polymerization where the monomer is added to water with or without an emulsifier and polymerized with the help of a water-soluble initiator and initiation of particles in the water phase is obtained. The method produces particles in the range of up to approx. 0.6 µm in diameter. Size and monodispersity increase with decreasing amount of emulsifier. The particles can further be produced by initiation in droplets, which can be produced in different ways. One can e.g. homogenize a mixture of monomer with a small amount of a water-insoluble material with water solubility less than 10 -3 g/l HjO with water and emulsifier, which gives stable monomer emulsions, and then polymerize with addition of initiator and heating. The water-insoluble substance used may be a water-insoluble monomer. If desired, an oil-soluble initiator can be used which is added together with monomer before homogenization. Optionally, this initiator can itself serve as the water-insoluble substance that gives stable monomer emulsions. With this method, initiation can be achieved exclusively inside the droplets.

He can also in the first step homogenize a water-insoluble substance with a water solubility less than 10 g/l HjO with water and emulsifier. Monomer is then added, which will diffuse into the droplets of water-insoluble substance and polymerize using a water-soluble initiator or an oil-soluble initiator that is added together with or after the monomer, and which has enough water solubility that, like the monomers, it can diffuse through the water and into the droplets of water-insoluble matter. Also

in this case, the water-insoluble substance used during the homogenization can be an initiator.

The polymer particles can also be produced by seed processes. In this case, one uses a seed of polymer particles that are dispersed in water, possibly a mixture of water and an organic solvent soluble in water, and one introduces the desired monomers into the polymer particles before polymerizing either with a water-soluble initiator or with an oil-soluble initiator that is added together with or after the monomers. In many cases, especially for the production of larger particles, a seed technique can be used which involves in a first step producing particles which, in addition to the polymeric molecules, contain a water-insoluble substance with a relatively low molecular weight. Such a method is described in Norwegian patent 142,082. When the water-insoluble substance with a water solubility of less than 10 ^ g/l H^ O and with a relatively low molecular weight is present in the particles, these will, as described in the aforementioned patent, be able to absorb far more monomer than ordinary polymer particles.

A special variant of this method, which has also proved beneficial for the production of polymer particles which are subsequently to be transferred to magnetic particles, includes that the water-insoluble substance used for swelling the polymeric particles in the first step is an oil-soluble initiator which is used for polymerization after monomer has diffused into the particles.

The production of polymer particles with the seed technique is

particularly beneficial when you want to produce spherical magnetic particles which are monodisperse and which will therefore also contain the same amount of magnetic ferrite in each particle. In this case, you start with a monodisperse seed, that is, a polymer dispersion where the particles all have approximately the same size, e.g. standard deviation less than 5%. The standard deviation for the content of magnetic ferrite will then normally be less than 10%. The polymeric particles can also be produced by ordinary suspension polymerization. In this case, you get directly large particles, but with a wide size distribution.

The particles produced according to the above

methods of polymerization in droplets or swollen particles,

can be obtained as porous particles using common methods which include using a mixture of monomers of which at least one is a polyvinyl compound and additionally having inert solvents for the monomers which are removed after polymerization. For the production of the polymeric particles, ordinary vinyl monomers and polyvinyl monomers and mixtures of these can be used. Examples of vinyl monomers used are styrene and styrene derivatives, maleic anhydride, acrylates and methacrylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate and butyl methacrylate, vinyl esters such as vinyl acetate. Examples of polyvinyl monomers that may be used include divinylbenzene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate and adipic acid divinyl ester. Usual ionic and non-ionic emulsifiers can be used as emulsifiers. Water-soluble initiators such as potassium persulphate and oil-soluble initiators such as azobis-isobutyric nitrile and benzoyl peroxide can be used as initiators. As inert materials that are used to stabilize emulsions of monomer or to increase the swelling ability of the polymer particles, substances mentioned in Norwegian patents 139,410 and 142,082 can be used.

Examples are alkanes with a chain length > 10 C atoms, halogenated alkanes, esters and diesters such as dioctyl adipate. Examples of water-insoluble initiators that are used both as additive material for increasing the swelling of particles with monomer and for polymerization are dioctanoyl peroxide and didecanoyl peroxide.

The preparation of dispersions of polymers in water can

also take place by dissolving the polymer in a solvent

which is poorly soluble in water and then mixes the solution of polymers with water and emulsifier and subjects the mixture to strong shearing forces, e.g. using an ultraturrax stirrer or pressure homogenizer, which results in a fine emulsion of polymer solution in water with varying droplet sizes. When removing the solvent, e.g. by evaporation, a finely divided dispersion of polymer particles is formed in water.

Introduction of metal salts into the particles can take place before or after removal of the organic solvent. In this case, where the polymer dispersion is produced from a finished polymer, it is irrelevant how the polymer is produced.

It can be produced by radical polymerization of vinyl monomers as described above, but can also be produced by any other process leading to polymers, such as cationic and anionic polymerization, stepwise addition polymerization, and condensation polymerization.

100 ml of methyl methacrylate, 90 ml of glycidyl methacrylate, 10 ml of ethylene glycol dimethacrylate and 1750 ml of HgO were mixed in a reactor. The mixture was subjected to rapid stirring for 1 30 min. 2.0 g (NH^Og dissolved in 150 ml of water was then added. The temperature was raised to 65°C and it was polymerized for 16 h. After polymerization, a latex is obtained which contains 10% polymer, the particle size is 0.2-0, 3 etc.

100 ml of the latex was treated with 100 ml of ethylenediamine at 80°C for 13 hours. After the reaction, excess ethylenediamine was removed by dialysis for 10 days, with water changes every day.

Elemental analysis showed that the particles contained 4.6% N by weight.

50 ml of dialyzed latex containing 5 g of particles treated with ethylenediamine was cooled to 10°C.

811 mg (3.0 m mol) FeCl 2 . 6 HgO was dissolved in 20 ml of water and cooled to 10°C. Correspondingly, 338 mg (1.7 n mol) of FeC12*4 h^O were dissolved in 20 ml of water and cooled down to 10°C. The two ferric chloride solutions were combined and then mixed with the latex in a rotating container which was rapidly evacuated to 10 mm Hg. After 20 minutes, 10 ml of cold (10°C) ammonia solution (25%) was added by suction. The vacuum was then removed and the temperature raised to 80°C. After 30 minutes at 80°C, the mixture was cooled and the particles separated from the solution by centrifugation. The particles were washed several times with water to remove excess ammonia and formed ammonium chloride.

After this treatment, the particles contain magnetic iron oxide.

The iron content of the particles was determined to be 4.9%

Example 2.

200 ml methyl methacrylate, 10 ml stearyl methacrylate, 75 ml glycidyl methacrylate,

15 g of ethylene glycol dimethacrylate, 1500 ml of H 2 O and 4.5 cetyltrimethylammonium bromide were homogenized into an emulsion with a droplet size of 0.2-0.4 µm. The mixture was transferred to a 4 L reactor. 1.9 g NaHCO 3 and 1150 ml H 2 O

was added. The reactor was evacuated and filled with 99.9% N2 in several operations and then 9 g of H202 (30% active) dissolved in 150 ml of HgO were added. The temperature was raised to 60°C. After polymerization, a latex is obtained with a particle size of 0.2-0.4 ym and a dry matter content of 9.5X.

Treatment with ethylenediamine for the introduction of primary amino groups was carried out as described in example 1. After this treatment, the particles contained 2.8% N. 30 ml of dialyzed latex containing 3 g of particles treated with ethylenediamine was added to ferric chloride and ammonia solution as described in example 1. In this case, 514 mg (1.9 m mol)-FeCl3-6 H20 1 20 ml water, 219 mg (1.1 mmol) FeCl2- 4 H20 in 20 ml water and 8 ml ammonia solution (25h) were added . The further processing and processing of the particles was carried out as described in Example 1.

The finished particles contain magnetic iron oxide. The iron content of the particles was determined to be 5.2 X.

Example 3.

10 ml of hexadecane, 50 ml of H 2 O and 0.15 g of Na-1-auryl sulfate were homogenized into an emulsion with a droplet size of 0.2-0.7 pm. The mixture was transferred to a reactor. 800 ml of H 2 O and 1.0 g of Na-lauryl sulfate were added. While stirring, a mixture of 130 ml of methyl methacrylate, 60 ml of glycidyl methacrylate, 10 ml of ethylene glycol dimethacrylate and 4 g of azo-bis-iso-butyronitrile was slowly added. After 2 hours the temperature was raised to 60°C. The polymerization takes 6 hours and you get a latex with a particle size of 0.5-2.ym and a solids content of 19%. Treatment with ethylenediamine for the introduction of primary amino groups was carried out as described in example 1. After the reaction, excess ethylenediamine was removed by separating the particles and subjecting them to several washings with water in a centrifuge.

Elemental analysis showed that the particles contained 3.5 t of N.

25 ml of a latex containing 2.9 g of particles treated with ethylenediamine was added ferric chloride and ammonia solution as described in example 1.

In this case, 649 mg (2.4 mmol) of FeCly 6 H 2 O dissolved in 20 ml of water, 278 mg (1.4 mmol) of FeCl 2 * 4 H 2 O dissolved in 20 ml of water and 10 ml of ammonia solution { 25%) were added. The further processing and processing of the particles was carried out as described in Example 1.

The finished particles contain magnetic iron oxide. The iron content of the particles was determined to be 6.6 X.

Example 4.

10 ml of dioctanoyl peroxide, 30 ml of H 2 O and 0.03 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.2-0.7 µm.

The mixture was transferred to a reactor. 800 ml of water and 1.0 g of Na-lauryl sulfate were added. While stirring at 25°C, a mixture of 110 ml of methyl methacrylate, 90 ml of glycidyl methacrylate and 10 ml of ethylene glycol dimethacrylate was slowly added. After 2 hours the temperature was raised to 65°C. After completion of the polymerization, a latex was obtained with a particle size of 0.5-2 um and a solids content of 19%. Treatment with ethylendiamine for the introduction of primary amino groups was carried out as described in Example 3. Elemental analysis showed that the particles contained 4.6% N. 30 ml of a latex containing 2 g of particles treated with ethylenediamine was added to ferric chloride and ammonia solution as described in Example 1 1.

In this case, 514 mg (1.9 mmol) FeCl3 <*> 6«20 1 20 ml water, 219 mg .

(1.1 mmol) FeC12«4 HgO 1 20 ml of water and 10 ml of ammonia solution (25%) added. The further processing and processing of the particles was carried out as described in example 1.

The finished particles contain magnetic iron oxide. The iron content of the particles was determined to be 7.5%.

Example 5.

10 ml of dioctanoyl peroxide, 30 ml of H 2 O and 0.03 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.2-0.7 µm. The mixture was transferred to a reactor. 800 ml of water and 1.0 g of Na-lauryl sulfate were added. While stirring at 25°C, a mixture of 40 ml of glycidyl methacrylate, 40 ml of ethylene glycol dimethacrylate and 120 ml of cyclohexanol was slowly added. After 2 hours the temperature was raised to 60°C. After the polymerization is complete, a latex with a particle size of 0.5-2.0 um is obtained. Cyclohexanol is removed by repeated washing with water and isopropanol. After drying, a porous powder with a specific surface area of 115 m 2 /g (BET method) is obtained. 10 g of porous particles were treated with 100 ml of ethylenediamine at 80°C for 3 hours. Unreacted ethylenediamine was removed by centrifugation and repeated washing with h*20. Elemental analysis showed that the particles contained 5.8 « N. 3 g of dry particles treated with ethylenediamine were transferred to 20 ml of water and added ferric chloride and ammonia solution as described in example 1.

In this case, 1954 mg (3.9 mmol) FeCl3-6 h"20 in 20 ml water, 457 mg

(2.3 mmol) FeClg- 4 H20 in 20 ml of water and 15 ml of ammonia solution (25%) added. The further processing and processing of the particles was carried out as described in example 1.

The finished particles contain magnetic iron oxide. The Jeminn group 1 particles were determined to be 10.0 t.

Example 6.

5 ml of dioctanoyl peroxide, 50 ml of water and 0.15 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.15-0.25 µm. This emulsion was mixed with a latex consisting of polystyrene particles with a diameter of 0.5-1.0 µm. The amount of latex added (40 ml) contained 5 ml of polystyrene particles and 35 ml of HgO. After gentle stirring for 124 hours, the mixture was transferred to a reactor containing 800 ml of water and 2.4 g of Na-lauryl sulfate. 164 ml of methyl methacrylate, 140 ml of glycidyl methacrylate and 16 ml of ethylene glycol dimethacrylate were slowly added. After stirring for 2 hours, 800 ml of H 2 O were added and the temperature raised to 60°C. After the polymerization, a latex was obtained with a particle size of 2-4 µm and a dry matter content of 14.5 t. Treatment with ethylenediamine for the introduction of primary amino groups was carried out as described in example 1.

Removal of unreacted ethylenediamine was carried out as in example 3. Elemental analysis showed that the particles contained 4.5% N.

2.5 g of dry particles treated with ethylenediamine were transferred to 20 ml of water. The particles were treated with ferric chloride and ammonia solution as described in example 1.

In this case, 608 mg (2.3 mmol) of FeCl3«6 H20 in 20 ml of water, 249 mg

(1.3 mmol) FeCl2-4 H20 in 20 ml of water and 10 ml of ammonia solution ( 251) added. The particles were processed by filtration and washing with water and finally

with methanol before the particles were dried.

After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 7.1%.

Example 7.

5 ml of dioctanoyl peroxide, 50 ml of water and 0.15 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.15-0.25 µm. This emulsion was mixed with a latex consisting of monodisperse polystyrene particles with a diameter of 0.53 µm (determined by electron microscopy). The amount of latex added (31.25 ml) contained 5 ml of polystyrene particles and 26.25 ml of H 2 O. After gentle stirring for 124 hours, the mixture was transferred to a reactor containing 800 ml of water and 2.5 g of Na-lauryl sulfate. 304 ml of glycidyl methacrylate and 16 ml of ethylene glycol dimethacrylate were slowly added. After stirring for 2 hours, 800 ml of H 2 O were added and the temperature raised to 60°C. After the polymerization, a monodisperse latex was obtained with a particle size of 2.0 µm (determined by electron microscopy) and a solids content of 14.6 t.

Treatment with ethylenediamine for the introduction of primary amino groups was carried out as described in example 1. Removal of unreacted ethylenediamine was carried out as described in example 3. Elemental analysis showed that the particles contained 9.5% N. 2 g of dry particles treated with ethylenediamine were transferred to 20 ml of water. The particles were treated with ferric chloride and ammonia solution as described in example 1.

In this case, 930 mg (3.4 mmol) of FeCl 3 6 H 2 O in 20 ml of water, 390 mg (2.0 mmol) of FeCl 2 * 4 H 2 O in 20 ml of water and 15 ml of ammonia solution (25X) were added. The preparation of the particles was carried out as in example 6.

After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 12.5 t.

EXAMPLE 8

5 ni dioctyl adipate, 42.5 ml of water, 7.5 ml of acetone and 0.15 g of Na-lauryl sulfate were homogenized into an emulsion down to a droplet size of 0.2-0.3 jin. This emulsion was mixed with a latex consisting of monodisperse polystyrene particles with a diameter of 1.04 pm (determined by electron microscopy)). The amount of latex added (25 ml) contained 2.5 ni polystyrene particles and 22.5 ni H20. After gentle stirring for 20 hours, the acetone was removed by evaporation in vacuo and the latex transferred to a reactor containing 818 ni H 2 O and 2.3 g Na-lauryl sulfate. A mixture of 270 ni glycidyl methacrylate, 14 ni

ethylene glycol dimethacrylate and 5.7 g of benzoyl peroxide were added slowly with good stirring. After stirring for 2 hours, 818 ml of H2O were added and the temperature was raised to 60°C. After the polymerization, a nondisperse latex with a particle diameter of 5.0 jin (determined by electron microscopy) was obtained. Treatment with ethylenedianine to introduce primary amino groups was carried out as described in ex. 1. Removal of unreacted ethylenediamine was carried out as described in ex. 3. Elemental analysis showed that the particles contained 7.00% N.

3 g of particles treated with ethylenediamine were transferred to

25 ml of water. The particles were treated with ferric chloride and ammonia solution as described in example 1. In this case, 716 mg (2.6 mmol) of FeCl3 were obtained. 6 <H>2<0> in 25 ni water, 301 ng

(1.5 mmol) FeCl 2 . 4<H>20 in 25 ni water and 20 ni ammonia solution (25%) added.

The preparation of the particles was carried out as in example 6.

After treatment, the particles contain non-magnetic iron oxide. The iron content was improved to 7.0%.

EXAMPLE 9.

10 ni dioctanoyl peroxide, 85 ni water, 15 ni acetone and 0.30

g Na-lauryl sulfate was homogenized to an emulsion down to a droplet size of 0.2-0.3 pm. This emulsion was mixed down 37

nine of a latex consisting of monodisperse polyner/oligoner particles (where each particle contained 70% oligomeric styrene of zero weight 2500 and 30 t polystyrene) down to diameter 1.0 pm (measured by Coulter Nano Sizer). The called latex zone was added containing 4 ni polymer/oligomeric particles and 33 ml H 2 O. After gentle stirring for 20 minutes, acetone was removed by evaporation in vacuo. Amount of latex after removal of acetone was 132 ni.

A mixture of 81.5 nits of glycidyl methacrylate, 122 nits of ethylene glycol dimethacrylate, 314.5 nits of cyclohexanol, 1450 nits of H 2 O and 20 g of polyvinylpyrrolidone (zero weight 360,000) was emulsified down an ultraturrax nixer for 1 1/2 nin. The emulsion was transferred to a reactor and the aforementioned latex residue of 132 ni was added.

This mixture was stirred at moderate stirring speed for 2

thaws. Then 1450 ni water was added and the temperature raised to 60°C. After the polymerization, the reactor was cooled and cyclohexanol was removed by repeated washing down with water and isopropanol. After drying, nan 155 g of nonodisperse porous particles were obtained down to dianether 4.8 pm (determined by electron microscopy) and specific surface area 151 n'/g polymer (BET).

Treatment with ethylenediamine for the introduction of primary amino groups was carried out as described in example 5. Treated ethylenediamine was removed by centrifugation and repeated washing with water. Elemental analysis of dry particles showed that they contained 4.9% N.

S g particles treated with ethylenediamine were transferred to

40 nine water. The particles were treated with ferric chloride and ammonia solution as described in example 1.

In this case, 1.50 g (5.5 mmol) of FeCl 3 . 6H20 in 25

ml water, 0.64 g (3.0 mmol) FeCl2 . 4 HjO in 25 ml water and 25 ml ammonia solution (25%) added.

The processing of the particles was carried out as in example 6. After the treatment, the particles contain magnetic iron oxide. The iron content was determined to be 8.5%.

EXAMPLE 10

5 ni doctanoyl peroxide, 42.5 ni B20, 7.5 ni acetone and 0.15 g Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.2-0.4 µm. This emulsion was mixed into a latex consisting of non-disperse polymer/oligomer particles with a diameter of 1.0 µm. The last latex added, 18.5 mol, contained 2 mol polymer/oligomeric particles and 16.5 mol H₂O.

After careful stirring for 20 minutes, the acetone was removed by evaporation in vacuo, residue 66 ni. This was transferred to a reactor zone containing 800 ni H2o and 3.25 g Na lauryl sulfate.

A mixture of 40 ni diethylaninoethyl methacrylate, 90 ni ethylene glycol dimethacrylate and 200 ni cyclohexanol was added slowly with good stirring. After 2 thaws, 800 liters of water were added and the thawing temperature was raised to 60 °C. After 6 hours of polymerization, the reactor was cooled down and cyclohexanol was removed from the particles by repeated washing down with B20 and isopropanol. After drying, nan obtained 110 g of nonodisperse porous polymer particles with a diameter of 4.7 µm and a specific surface area of 222 m/g of polymer

(BET). Elemental analysis showed that the polymer particles contained

1.7% N, i.e. 1.2 mmol

groups per g polymer.

5 g of particles were transferred to 50 ni of water and treated with ferric chloride and ammonia solution as described in Example 1. In this case, 1027 mg (3.8 mmol) FeCl3.6 HjO in 25

nine water, 434 ng (2.2 mmol) FeCl2.4H20 in 25 ml water and 20

ml ammonia solution (25%) added.

After treatment, the particles were filtered from the solution and washed with water and finally with methanol. The particles were then dried.

After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 6.1%.

EXAMPLE 11

2 ml of Trigonox 21 S (t-butyl-peroxy-2-ethylhexanoate), 2 ml of dioctyl adipate, 40 ni of water and 0.12 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.15-0.25 pm. This emulsion was mixed with a latex consisting of monodisperse polymer/oligomer particles with a diameter of 1.0 µm. The amount of latex that was added, 18.5 ml, contained 2 ml of polymer/oligomer particles and 16.5 ml of H2o. After gentle stirring for 24 hours, the mixture was transferred to a reactor containing 700 ml of B20 and 2.5 g of Na-lauryl sulfate. A mixture of 33 ml of 4-vinylpyridine, 50 ni divinylbenzene (50%) and 167 ml of toluene was slowly added. After good stirring for 16 hours, 1.5

g Berol 292 (nonylphenol ethoxylate with 20 mol of ethylene oxide per mol of nonylphenol) and 750 ml of water added. The temperature was raised to 70°c, and polymerization was carried out until complete conversion.

After cooling, the toluene was removed by repeated extraction with acetone. After drying, 70 g of monodisperse porous polymer particles with a diameter of 4.7 pm and a specific surface area of 193 nr/g polymer (BET) were obtained. Elemental analysis" showed that the particles contained 6.0% N.

654 mg (2.4 mmol) of FeCl3.6H20 were dissolved in 25 ml of water and cooled to 10°c. Correspondingly, 274 mg (1.4 mmol) of FeCl2.4B20 were dissolved in 25 ml of water and cooled down to 10°c. These two solutions were combined and then 50 ml of methanol, which had previously been cooled to 10 °C, was added. To this mixture was added 1 g of dry particles and the whole was transferred

to a rotating vessel that was evacuated to 10 mm Hg. After 30 minutes, 10 ml of cold (10°c) ammonia solution was added

(25%) added by absorption. The vacuum was then removed and the temperature raised to 80°c. After 15 minutes at 80°C

the mixture was cooled and the particles filtered off. The particles were washed with water and finally with methanol and then dried. After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 16.4%.

EXAMPLE 12

5 ml of dioctanoyl peroxide, 42.5 ni of water, 7 ni of acetone and 0.15 g of Na-lauryl sulfate were homogenized into an emulsion down to a droplet size of 0.2-03 pm. This emulsion was mixed with a latex consisting of non-disperse polystyrene particles down to dianether 0.53 pm. The amount of latex added (20.83 ml) contained 3.33 ni polystyrene particles and 17.50 ni BjO. After gentle stirring for 20 minutes, the acetone was removed in vacuo and the latex transferred to a reactor containing 800 n of water and 3.25 g of Na-lauryl sulfate. A mixture of 100 ni divinylbenzene (50%)

and 200 ni toluene was slowly added. After good stirring for 16 hours, 800 ni H 2 o and 4.0 g Berol 292 (nonylphenol ethoxylate down to 20 noi ethylene oxide per noi nonylphenol) were added. The temperature was raised to 70°c and polymerization took place until complete conversion.

After cooling, toluene was removed by repeated extraction with acetone. After drying, nan obtained 82 g of nonodisperse porous particles down to dianether 2.0 µm and specific surface area 472 n<2>/g polymer (BET).

5 g of dry particles were transferred to a mixture of 50 ml of concentrated nitric acid and 125 ml of concentrated sulfuric acid with stirring during 30 minutes. 40 minutes after the end of particle addition, the reaction mixture was poured into a container containing 1 liter of ice. The particles were filtered from the solution and washed with water (400 mL) and finally with ethanol (200 mL). After drying, 5 g of the particles were

passed to a rotating vessel together with 10 g of FeS04„7H20

dissolved in 150 ni water. The container was then evacuated to 10 nm Bg. After 45 minutes, 50 ml of ammonia solution (25%) was added by suction. The vacuum was then removed and the temperature raised to 80°c. After 15 minutes at 80°C, the mixture was cooled and filtered. The particles were first washed down with water

(400 ni) and finally netanol (200 ml). The particles were then dried. After this treatment, the particles contain

nagnetic iron oxide. The iron content of the particles was

best to 20.0%.

EXAMPLE 13

Monodisperse porous particles were prepared as described

1 example 12.

S 9 porous particles, 1 g polyaminaroid (Versamid-115) and

100 ml of toluene was mixed and transferred to a rotating container which was then evacuated (10 mm Hg). The temperature in the mixture was kept between 5 and 10°c. After one hour the temperature was raised and the mixture evaporated to dryness.

2 g of these particles in 40 ml of methanol were then treated with ferric chloride and ammonia solution as described in example 1 to form ferromagnetic iron oxide in the particles. IN

in this case, 520 mg (1.9 mmol) FeCl3.6H20 in 25 ml water, 220 mg (1.1 mmol) FeCl2.4H2<0> in 25 ml water and 10 ml ammonia solution (25%) were added.

The particles were separated from the solution by filtration, washed

with water and finally with methanol. The particles were then dried. The finished particles contain magnetic iron oxide. The iron content was determined to be 5.2%.

EXAMPLE 14

In a reactor equipped with an impeller-type stirrer, 1800 ni of water, 4.8 g of Gelvatol 20-60 (polyvinyl alcohol 80% hydrolyzed) and 0.012 g of Na-lauryl sulfate were added. To this was

a mixture consisting of 80 ni styrene, 120 ni divinylbenzene (50%), 200 ni heptane, 200 toluene and 3 g azobisisobutyronitrile was added. They were all subjected to intense stirring for 30 nin.

before the temperature was raised to 70°c. The polymerization took place under vigorous stirring during 5 thaws. After cooling, the polymer was filtered from the water phase and toluene/heptane removed by repeated extraction into acetone. After drying, nan obtained 180 g of a porous powder down to particle size 5-50 pm and specific surface area 234 n<2>/g.

For introduction of N02_grUpper with subsequent processing

with 2- and 3-valent iron for magnetization of the particles. the same method as described in example 12 was used.

After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 17.3%.

EXAMPLE 15

In a reactor with blade stirrers, 225 ml of water was added and

0.6 g Gelvatol 20-60 (polyvinyl alcohol 80% hydrolyzed).

To this was added a mixture consisting of 10 ml of 3-nitrostyrene, 15 ml of divinylbenzene (75%), 25 ml of toluene, 25

ml of heptane and 0.375 g of azobisisobutyronitrile. The whole was subjected to intense stirring for 30 min. before the temperature was raised to 70°c. The polymerization took place under vigorous stirring until complete conversion. After cooling, the polymer was filtered from the water phase and the toluene was removed by several extractions with acetone. After drying, 23 g of a porous powder with a particle size of 10-60 µm and a specific surface area of 254 were obtained.

m<2>/g (BET).

1 g of these porous particles was transferred to a rotary

container together with 1.4 g of PeSO4.7H20 dissolved in 40 ml of water. The container was then evacuated to 10 mm Bg. After 45 minutes, 10 ml of ammonia solution (25%) was added by suction. The vacuum was then removed and the temperature raised to 80°c. After 15 minutes at 80°C, the mixture was cooled and filtered.

The particles were first washed with water (100 ml) and finally

with methanol (25 mL). The particles were then dried. After this treatment, the particles contain magnetic iron oxide. The iron content in the particles was determined to be 19.8%.

EXAMPLE 16

5.0 ml of dioctanoyl peroxide, 42.5 ml of H20, 7.5 ml of acetone and 0.15 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.2-0.4 µm. This emulsion was mixed with 15.72 ml of a latex consisting of monodisperse polystyrene particles with a diameter of 0.46 pm (determined by electron microscopy). The amount of latex that was added contained 2.5 ml of polystyrene particles and 13.22 ml of H2o. After gentle stirring for 20

hours, the acetone was evaporated in a vacuum and the latex was transferred to a reactor containing 800 ml of B2o and 3.0 g of Na-lauryl sulphate. A mixture of 201.6 ml methyl methacrylate, 22.4 ml ethylene glycol dimethacrylate and 96.0 ml methacrylic acid was added slowly with good stirring. After stirring for 1 hour, 800 ml of H 2 O were added and the temperature raised to 65°C. After 2 hours of polymerization, 1.6 g of Berol 292 was added. The polymerization was continued until complete conversion and man.obtained

a monodisperse latex with particle diameter 2.3 µm (determined by electron microscopy).

For further treatment, the particles were separated from the water phase

by centrifugation. The particles were washed with acetone and dried.

2 g of dry particles were then transferred to 50 ml of sodium hydroxide solution (2%) in a glass flask equipped with a stirrer.

After 20 minutes of stirring, the particles were separated from the solution

by centrifugation. It was then alternately washed with water and centrifuged several times until the washing water had an approximately neutral pB. The particles were then transferred to 50 ml of water and treated with ferric chloride and ammonia solution as described in Example 1. In this case, 334 mg (1.3

mmol) FeCl3.6B20 in 20 ml water, 145 mg (0.7 mmol) FeCl2.<4H>2<0>

in 20 ml of water and 10 ml of ammonia solution (25%) added. The preparation of the particles was carried out as in example 6.

After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 5.2%.

EXAMPLE 17

Porous, monodisperse particles with a diameter of 2.0 nm prepared as described in example 12 were treated with chloromethyl ether, ClCH^OCHj, according to known methods for introducing -CHjCl

on the benzene nucleus. Porous particles with 1.2 mmol -CH2C1 groups per g particles.

100 ml of polyethylene glycol, HO(CH2CH20)nH, with average n = 30, 100 ml of tetrahydrofuran and 1.5 g of NaH were mixed in a three-necked flask under a nitrogen atmosphere and kept under stirring at 50°

for 2 hours. 10 g of the chloromethylated particles produced above were added, and the whole heated under reflux for 2 days. After completion of the reaction, the particles were separated by filtration and washed repeatedly with tetrahydrofuran. Finally, the particles were dried under vacuum.

2.8 g of dry particles were treated with ferric chloride and ammonia as described in Example 1. In this case, 1300 mg (4.8 mmol) FeCl 3 -6H 2 O and 450 mg (2.4 mmol) FeCl 2 -4H 2 O were used.

The particles were separated from the solution by filtration, washed with water and finally with methanol. The particles were then dried. After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 10.5%.

EXAMPLE 18

Porous, monodisperse particles with a diameter of 2.0 µm prepared

as described in example 12 was processed according to known methods

with chloromethylphthalimide.

and then hydrazine to introduce -CH2NH2 groups on the benzene nucleus. A product with 1.3 mmol -CH2NH2 groups per g particles. 5 g of dry particles were treated with 20 g of epoxy polyethylene glycol monoethyl ether,

and the mixture

was kept under nitrogen atmosphere and gentle stirring in a three-necked flask at 90° for 24 hours. The particles were then separated by filtration and washed repeatedly with tetrahydrofuran until

all extractable material was removed, and then dried.

2.8 g of dry particles were treated with ferric chloride and ammonia as described in example 1. In this case, 1300 mg of FeCl3-6H20 and 450 mg of FeCl2-4H20 were used.

The particles were separated from the solution by filtration, washed with water and finally with methanol. The particles were then dried. After treatment, the particles contain ferromagnetic iron oxide. The iron content was determined to be 10%.

EXAMPLE 19

To 100 ml of acetone solution containing 6.2 mmol of FeCl 2 and 3.1 mmol of FeCl 2 were added 3 g of dry, porous monodisperse particles with polyethylene oxide groups bound to the benzene core. The production of the particles is described in example 17.

The particle suspension in acetone was stirred for 30 minutes under a nitrogen atmosphere. The particles were then filtered from on

a suction funnel while maintaining a blanket of nitrogen over the filter cake all the time. After all excess liquid was removed, the particles were treated with a stream of moist NH 2 steam. The particles were then washed with water and finally with methanol. The particles were then dried.

After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 9.5%.

EXAMPLE 20

A linear polyamide was prepared according to known methods from equimolar amounts of 1,11-diamino-3,6,9-trioxaundecane.

NH2-CH2-CH2-(0CH2C<H>2)3NH2 and sebacic acid dichloride,

by dissolving the two reactants in water and carbon tetrachloride respectively and performing an interfacial polymerization. 10 g of purified polyamide dissolved in 100 ml of methylene chloride, 200 ml of H 2 O and 0.3 g of cetylpyridinium bromide were homogenized to a droplet size of 0.3-2 pm. Methylene chloride was then removed by evaporation in vacuo. 10 ml of aqueous dispersion containing 1.6 g of polyamide particles was treated with ferric chloride and ammonia as described in example 1. In this case, 1000 mg of FeCl3-6H20 and 350 mg of FeCl2-4H20 were used.

The particles were separated from the solution by filtration, washed with water and finally with methanol. The particles were then dried. After treatment, the particles contain magnetic iron oxide. The iron content was determined to be 11.5%.

Example 21

5.0 ml of dioctanoyl peroxide, 42.5 ml of H 2 O, 7.5 ml of acetone and 0.15 g of Na-lauryl sulfate were homogenized into an emulsion with a droplet size of 0.2-0.4 µm. This emulsion was mixed with 23.1 ml of a latex consisting of monodisperse polystyrene particles of diameter 0.95. The amount of latex added contained 2.5 ml of polystyrene particles and 20.6 ml of B 2 O.

After careful stirring for 24 hours, the acetone was evaporated in vacuo. Amount of latex after removal of acetone was 71 ml.

A mixture of 52 ml of hydroxyethyl methacrylate, 78 ml of ethylene glycol dimethacrylate, 200 ml of cyclohexanol, 800 ml of water and 10 g of Pluronic F 68 (polyethylene oxide derivative) was emulsified with the ultraturrax mixer for 1 1/2 min. The emulsion was transferred to a reactor and the aforementioned latex residue of 71 ml was added. This mixture was stirred at moderate stirring speed for 2 hours. Then 800 ml of water was added and the temperature raised to 60°C. After the polymerization, the reactor was cooled and cyclohexanol was removed by repeated washing with water and isopropanol. After drying, 125 g of monodisperse porous particles with a diameter of 4.0 µm and a specific surface area of 128 m<2>/g (BET) were obtained.

1.5 g of dry particles were treated with a mixture of

25 ml of concentrated nitric acid and 65 ml of concentrated sulfuric acid with stirring for 1 hour. The mixture was then poured into a container containing 1 liter of ice. The particles were filtered off and washed until the wash water had a neutral pH. After drying, the particles were transferred to a rotating container together with 2.06 g of FeSO 4 -7H 2 O dissolved in 25 ml of water. Under N 2 atmosphere, the mixture was rotated for 30 min. Then 10 ml of ammonia solution (25%) was added by suction. The temperature was then raised to 80°C. After 15 min. at 80°, the mixture was cooled and filtered. The particles were washed repeatedly with water and methanol.

After this treatment, the particles contain magnetic iron oxide. The iron content of the particles was determined to be 18.4%.

Example 22

Monodisperse porous particles were produced

as described in example 21. The particles had a diameter of 4.0 pm and a specific surface area of 128 m 2 /g.

1 c of dry particles was added to 7.5 g of NaN0 2 dissolved in

15 ml of water under vigorous stirring with a magnetic stirrer. The mixture was then cooled to 0°C in an ice bath. During possibly 50 min. was added dropwise to 10 ml of concentrated hydrochloric acid. The mixtures were then warmed to 20°C over 3 hours. The mixture was poured over 40 g of ice and filtered. It was washed with 1M Na-carbonate solution until the filtrate was neutral, then several times with water.

After drying, 0.87 g of particles were added to a solution of

1 g of FeS04«7H20 dissolved in 30 ml of water. The mixture was bubbled through with Li 2 (99.99%) and under N 2 atmosphere the mixture was rotated for 30 min. Then 10 ml of ammonia solution (25%) was added by suction. Under continued N2 atmosphere, the temperature was raised to 80°C. After 10 min. at 80°, the mixture was cooled and filtered. After repeated washing, the particles were dried at 60°C. After this treatment, the particles contain

magnetic iron oxide. The iron content of the particles was determined to be 12.3%.

Example 23

Monodisperse porous particles were produced

as described in example 9. The particles had a diameter of 4.6 pm, a specific surface area of 151 m <2>/g and after treatment with ethylenediamine the particles contained 4.9% N.

1 g of dry particles was mixed with 834 mg of FeSO 4 *7H 2 O

(3 mmol) dissolved in 40 ml of water. The mixture was rotated for 30 min. under N2 atmosphere. Then 10 ml of concentrated ammonia

solution (25%) added by suction. The temperature was then raised to 80°C under a weak suction of air through the apparatus.

After 15 min. at 80°C the mixture was cooled and the particles washed repeatedly with water and finally dried. After this treatment, the particles contain magnetic iron oxide. The iron content of the particles was determined to be 10.5%.

Example 24

Monodisperse porous polymer particles with amino groups were used, prepared as described in Example 9. The particles had a diameter of

4.8 µm and after treatment with ethylenediamine the particles contained 4.9% N.

1 g dry particles were added to 243 mg FeCl3«6 H20 (o.92 mmol) dissolved 1

15 ml H20 and 129 mg CoS04*7H20 (o.46 mmol) dissolved in 1 3o ml H20. The mixture was rotated 1 flml in the evaporator at 25°C under vacuum for 10 min. The vacuum was then removed and the mixture rotated at 90°C for 15 min. Then 30 ml of 6N NaOH was added. Irrigation was continued at 9o°C for 11 hours. The particles were then cleaned by repeated washing with water

and finally dried. After this treatment, the particles contain a

magnetic material. Analysis of the particles showed a content of

4.4% Fe and 2.3% Co.

Example 25

Monodisperse porous particles with nitrogen groups were used, prepared as described in example 12. The particles had one diameter of 2.0 µm and after filtration the particles contained 8.8% N. 2 g of dry particles were added to 1.6 g of FeSO4«7H20 (5.75 mmol) dissolved 1 25 ml H20 and about 8 g CoS04*7H20 (2.84 mmol) dissolved in 140 ml H20. The mixture was rotated in a fume hood at 25°C under N 2 atmosphere for 130 min. Then 25 ml of 3N NaOH were added and the whole was heated at 8o°C for 1 hour under an N2 atmosphere. After this treatment, the particles contain a magnetic material. Analyzes of the particles showed a content of 11.5% Fe and 6.1% Co.

Example 26.

Non-disperse polymer particles with amino groups were used, prepared as described in example 7. The particles had a diameter of 2.0 pi and after treatment with ethylenediamine the particles contained 9.5% N. 1 g of dry particles were transferred to 20 ml of water and 243 mg of FeC13*6 were added H20 (0.92 mmol) dissolved in 1 15 ml H20 and 91 mg MnCl2*4 H£0 (o.46 mmol) dissolved in 1 15 ml H20. The mixture was rotated 1 flml in the evaporator at 25°C under vacuum for 10 min. Then 2o ml of 3N NaOH was added and the whole was heated at 9o°C for 1 hour under an N2 atmosphere. The particles were then cleaned by repeated washing with water and finally dried.

After this treatment, the particles contain a magnetic material. Analyzes of the particles showed a content of 4.3% Fe and 2.2% thaw.

Example 27

5 ml dioctanoyl peroxide, 42.5 ml H20, 7.5 ml acetone and

0.15 g of Na-lauryl sulfate was homogenized into an emulsion with a droplet size of 0.2-0.4 pm. This emulsion was mixed with 28 ml of a latex consisting of monodisperse polystyrene particles with a diameter of 2.0 µm. The amount of latex added contained 2.27 ml of polystyrene particles and 25.73 ml of H 2 O.

After gently stirring this mixture for 24 hours each

all added dioctanoyl peroxide has been taken up by the polystyrene particles. Acetone was then removed by evaporation in a vacuum,

and a residue of 75.5 ml of latex containing 7.27 ml of polystyrene dioctanoyl peroxide particles was obtained. A mixture of 800 ml of water, 0.6 g of Na-lauryl sulfate, 12 g of polyvinylpyrrolidone

(MV 360 O00), 60 ml ethyl acrylate, 90 ml divinylbenzene (50%) and

150 ml cyclohexanol was homogenized using an ultra turrax mixer. The mixture was transferred to a reactor and then the above latex of 75.5 ml was added. The reactor was then closed and stirring was carried out at 25°C for 20 hours. Then 800 ml of B20 were added and the reactor heated to 60°C. Polymerization was carried out for 2 hours at 60°C and then for 5 hours at 70°C until complete conversion. After washing the product with water and isopropanol, filtering and drying, a powder consisting of monodisperse macroporous polymer particles with

diameter 9.8 pm.

5 g of dry particles were mixed with 50 ml of diethylenetriamine

in a small wooden-necked flask equipped with stirrers and a short fractionating column. The temperature was gradually raised to 200°C. Heating was continued for 5 hours. Ethyl alcohol distilled off through the column. After dilution with water, the particles were purified by filtration and repeated washing with water and finally drying. Elemental analysis showed that the particles contained 3.2% N.

2 g of particles were transferred to 20 ml of water and treated with ferric chloride and ammonia solution as described in example 1. In this case, 690 mg (2.55 mmol) of FeCl3.6H20 was used

in 25 ml of water and 288 mg (1.45 mmol) of FeCl 2 -4H 2 O in 25 ml of water, and 20 ml of ammonia solution (25%) were added.

After treatment, the particles were filtered from the solution and washed with water and finally with methanol. The particles were then dried. After this treatment, the particles contain magnetic iron oxide. The iron content was determined to be 9.5%.

Claims (9)

1. Process for the production of magnetic polymer particles, particularly monodisperse, characterized in that solutions of salts of iron and at least one of the metals Ni, Co and Mn in water or in a mixture of water and water-soluble organic solvents or in organic solvents are mixed with polymer particles, which optionally contains groups that can bind and/or react with metal salts, in dry form or dispersed in water or in a mixture of water and water-soluble organic liquids or in organic liquids, and the pH value is raised to precipitate metal hydroxides, after or during the addition of water if water is not present, and possibly heating the particles. 2. Method according to claim 1, characterized in that a) polymer particles are used which contain groups that can bind metal salts so that the essential part of the metal salts that are added is bound on and/or in the particles, after which the pH is increased and in case you have a suitable mixture of 2-valent metal salt and 3-valent iron salt, a mixture of Me(OH)2 is formed (where Me is at least one of Ni, Co and Mn and possibly also Fe<11>) and Fe(OH) 3 which produces magnetic oxide on and in the particles, and in the event that you have a higher than desired amount of 2-valent iron in the formed salt, this oxidizes after raising the pH, to a mixture of Me(OH)2 and Fe(OH )3 which gives magnetic oxide on and in the particles, b) polymer particles containing groups which have an ability to oxidize Fe(OH)2 to a mixture of Fe(OH)2 and Fe(OH)3, so that nickel-, cobalt and/or manganese salt as well as 2-valent iron salt that is added, when the pH is raised, is bound in the particles and transferred to magnetic oxide, c) polymer particles that are cross-linked, and to these is added an optional aqueous organic solvent containing a metal salt with hydrophobic anions that is soluble in said solvent, whereby the particles take up the given solvent so that the metal salts are introduced into the particles, after which the particles are isolated and water is added and The pH is raised so that a mixture of Me(OH)2 and Fe(OH)3 is formed which, possibly after oxidation as in a), gives magnetic oxide, d) solid, porous polymer particles to which a material is added that will bind to the surface inside in the pores and which contain groups that bind iron salt that is added. 3. Process according to claim 1 or 2, characterized in that the polymeric particles are produced by copolymerization of vinyl monomer with epoxy group and other vinyl monomers and/or polyvinyl monomers and are subsequently treated with substances containing one or more primary and/or secondary amino groups that react with the epoxy group so that these substances are bound on and in the particles and provide groups capable of binding metal salts with coordinative bonding. 4. Process according to claim 1 or 2, characterized in that a mixture of vinyl monomers and optionally polyvinyl monomers is copolymerized where one or more of the monomers contain amino groups and/or ethylene oxide groups, so that polymeric particles with amino groups are directly formed which by addition of a mixture of metal salts binds these on and in the particles, or where one or more of the monomers contain acid groups or groups that can be converted into acid groups, e.g. ester groups, which cause the formed polymer particles to contain acid groups which, in ionic form, will be able to bind metal salts by ionic bonds. 5. Method according to claim 1 or 2, characterized in that in order to obtain metal-binding primary and/or secondary and/or tertiary amino groups or acid groups on the inner surface of porous particles, substances are added which bind to the surface by physical adsorption and which contains the aforementioned groups which will bind metal ions so that, by subsequent addition of a mixture of metal salts, these are bound in and on the particles. 6. Method according to claim 1 or 2, characterized by using porous particles produced by copolymerization of a mixture of styrene, styrene derivatives or acrylates and divinylbenzene or di- or triacrylates in the presence of inert additives. 7. Method according to one of claims 1, 2 and 6, characterized in that polymer particles containing nitro groups are used. 8. Method according to one of claims 1, 2, 3 and 6, characterized by introducing amino groups, -CH2-CHR'-NH groups (R' = H or alkyl) or -CH2CH20- groups. 9. Method according to one of claims 1, 2 and 6, characterized in that acid groups, especially sulphonic acid or carboxylic acid groups, are introduced onto the finished polymerized particles.