JPS5915422A - Surface modification of water-dispersible high-molecular polymer particle - Google Patents

Abstract

PURPOSE:To modify only the surfaces of water-dispersible high-molecular polymer particles without changing their inherent properties, by reacting a polyamine with a dialdehyde in an aqueous dispersion of the high-molecular polymer particles and depositing a Schiff base of the polyamine with the dialdehyde on the surfaces of the particles. CONSTITUTION:The surfaces of water-dispersible high-molecular polymer particles (average particle diameter of 0.03-2mu, preferably 0.07-1mu) are modified by reacting a polyamine with a dialdehyde in an aqueous dispersion of the polymer particles and depositing a Schiff base of the plyamine with the dialdehyde on their surfaces. The above water-dispersible high-molecular polymer particles can be obtained by emulsion-copolymerizing a polar group-containing monomer (e.g., styrenesulfonic acid) with any desired monomer (e.g., ethylene or styrene), optionally in the presence of a polyfunctional monomer for internal crosslinking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface modification of water-dispersed polymer particles.

Conventionally, in order to modify emulsions, some of the copolymer components forming the polymer have been replaced, and seed polymerization has been used to improve the internal and external properties of water-dispersed polymer particles. It has also been proposed to vary the However, such methods change the inherent properties of the polymer, and cannot modify only the surface of the polymer while maintaining its inherent properties.

It is also known to carry out a chemical reaction on polymer particles as a method of modifying the surface of the polymer particles, but this method generally requires complicated treatments.

For example, to introduce amino groups onto the surface of polymer particles,
After copolymerizing acrylamide as a monomer component and subjecting the obtained polymer particles to Hoffmann degradation, or copolymerizing a monomer having a carboxyl group as a monomer component, diamine is dissolved in water. A known method is to convert the amino group into an amino group by reacting with a chemical carbodiimide. However, all of these methods are not only extremely complicated, but the former produces carboxyl groups as a side reaction, making it impossible to exclusively use amino groups, and the latter produces a large amount of carbodiimide. Polymer particles often aggregate due to the use of

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a method of modifying only the surface of a polymer while retaining its inherent properties.

The method for surface modification of water-dispersed polymer particles according to the present invention involves reacting a polyamine and dialdehyde in an aqueous dispersion of water-dispersed polymer particles. It is characterized by depositing the Schiff base of the polyamine and dialdehyde on the surface of the polyamine.

The water-dispersed polymer particles used in the present invention may be made of any polymer, and are appropriately selected depending on the use of the polymer particles, the purpose of modification, etc., and examples include ethylene, propylene, One or more of vinyl chloride, vinyl acetate, vinyl propionate, acrylic ester, methacrylic ester, styrene, methylstyrene, vinyltoluene, butadiene, isoprene, acrylamide, methacrylamide, acrylonitrile, methacrylic acid, etc. The monomers are obtained by emulsion polymerization according to conventional methods, with or without emulsifiers.

Preferably, the water-dispersed polymer particles used in the present invention are made of a polymer having a polar group in its side chain. Such water-dispersed polymer particles having a polar group can be obtained by mixing a monomer having a polar group with the above-mentioned monomer (hereinafter sometimes referred to as a copolymerizable monomer) according to a conventional method. It can be obtained by emulsion copolymerization. Here, as the polar group, for example, a sulfonic acid group, a carboxyl group,
Examples include acid groups such as phosphoric acid groups, basic groups such as tertiary amino groups, and quaternary amino groups. Specific examples of monomers having such polar groups include monomers having sulfonic acid groups such as styrene sulfonic acid and sulfobrobyl meccrylate, and monomers having carboxyl groups such as acrylic acid, methacrylic acid, and itaconic acid. monomers having a phosphoric acid group, such as acid phosphoxyethyl methacrylate, 3-chloro-2-acid phosphoxyethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylamide, etc. Examples include monomers having a tertiary amino group, monomers having a quaternary amine group such as methacrylamide propyltrimethylammonium chloride, and methacryloyloxyethyltrimethylammonium chloride.

Furthermore, in the present invention, in addition to the monomer having a polar group and the copolymerizable monomer copolymerizable therewith, a polyfunctional monomer for internal crosslinking can be emulsion copolymerized. . Specific examples of such internal fill crosslinking polyfunctional monomers include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, and 1,3-butylene glycol dimethacrylate. (meth)acrylates of polyhydric alcohols such as triethylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, etc. are preferably used. Divinylbenzene is also preferably used.

The use of a polyfunctional monomer for internal crosslinking suppresses the formation of undesirable water-soluble polymers in the emulsion copolymerization of a monomer having a polar group and the copolymerizable monomer, and also stabilizes the polymerization. Helps improve sex.

In the present invention, monomers having a polar group of 0.2 to 30
It is preferable to emulsion copolymerize 70 to 99.8% by weight of the copolymerizable monomer to obtain water-dispersed polymer particles. When copolymerizing also 20% by weight of the total monomer composition
It is best to use it within the range. This is because if too large a quantity is used, the stability of polymerization may be impaired.

The water-dispersed polymer particles used in the present invention have an average particle diameter of 0.03 μ to 2 tt, preferably 0.0
It is 7μ to 1μ. If the particle size is too small, the Schiff base consisting of polyamine and dialdehyde will not be deposited sufficiently uniformly on the surface, resulting in non-uniform surface modification, which is not preferred. On the other hand, if the particle size is too large, it becomes difficult to disperse in water and the surface modification becomes non-uniform, which is undesirable. Refers to an amine compound or polymer having two or more amines in the inside, preferably aromatic, aliphatic or alicyclic diamines or triamines, specifically phenylenediamine,
Xylylene diamine, phenylene triamine, triaminotoluene, ethylene diamine, hexamethylene diamine, etc. are used. Moreover, polyethyleneimine can also be used. However, diamines are particularly preferably used. As for the dialdehyde, aromatic or aliphatic dialdehydes are preferably used, and specifically, glutaraldehyde, succinic dialdehyde, glyoxal, maleic dialdehyde, terephthalic dialdehyde, etc. are used.

The equivalent ratio of polyamine and dialdehyde is appropriately selected depending on the water-dispersed polymer particles used and the purpose of modification. For example, when introducing an amino group onto the surface of a polymer particle, polyamine is used in excess, while when introducing an aldehyde group, dialdehyde is used in excess. In addition, particularly when there is no need to introduce such a reactive group, it is sufficient to use them in an approximately equivalent ratio. However, in any case, it is not preferable to use a 10-fold or more excess of one of the two because unreacted polyamine or dialdehyde will remain unnecessarily.

The reaction of polyamines with dialdehydes is carried out under conventional reaction conditions to produce thick bases. for example,
This is carried out by adding aqueous solutions of polyamine and dialdehyde to an aqueous dispersion of water-dispersed polymer particles and stirring, but the order in which the aqueous solutions of polyamine and dialdehyde are added is not particularly limited. The reaction usually proceeds smoothly when carried out under acidic conditions using hydrochloric acid or the like. Further, the reaction may normally be carried out at the product temperature for several hours. The higher the reaction temperature, the higher the reaction rate, but the stability of the water-dispersed polymer particles becomes worse, so it is usually desirable to carry out the reaction at a temperature of 50° C. or lower. Thereafter, if necessary, unreacted polyamine and dialdehyde are removed by an appropriate means such as centrifugation or membrane separation, and the water-dispersed polymer with the Schiff base deposited on the surface is removed. Obtain coalesced particles.

The reason why the surface of water-dispersed polymer particles can be modified by the method described above is not necessarily clear, but polyamine and dialdehyde react in water to produce a Schiff base, and the polyamine and dialdehyde react with each other in water. and are polyfunctional, and as the molecular weight of the Schiff base increases, it becomes water-insoluble and is deposited as a Schiff base polymer on polymer particles dispersed in water, changing the surface properties. Dew.

The surface-modified water-dispersible polymer particles obtained according to the present invention can be used for various purposes by taking advantage of their properties. For example, water-dispersed polymer particles prepared by using an excess of either polyamine or dialdehyde and depositing a Schiff base polymer have a large number of aldehyde groups or amino groups on their surface. It can be suitably used as a carrier for immobilizing various proteins such as enzymes, antigens, antibodies, hormones, etc. In addition, in the case of water-dispersed polymer particles having amino groups on the surface, by adding them to an aqueous dispersion of water-dispersible polymer particles having acidic groups or aldehyde groups, it is possible to coagulate them mutually. Since it precipitates, it can also be used as a flocculant. Furthermore, if water-dispersed polymer particles containing aldehyde groups or amino groups are reacted with water-soluble monomers or water-soluble polymers, they can be crosslinked, and can be used as a particulate crosslinking agent. Function.

As described above, according to the method of the present invention, a Schiff base is deposited on the surface of a polymer particle to modify only that surface. By a simple operation, a polymer can be deposited on the surface of a polymer particle and a reactive group can be introduced, so that the water-dispersed polymer particle itself becomes reactive or hydrophilic. , these characteristics can be used for various purposes.

The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 3 g of methacryloyloxyethyltrimethylammonium chloride, 1-80 g of methyl methacrylate, 1.2 g of triethylene glycol dimethacrylate, and 15 g of acrylonitrile were added to 230 g of distilled water, and 2,2'-azohy:su-2-amidinopronoprono <An aqueous polymerization initiator solution prepared by dissolving 0.3 g of dihydrochloride in log water was added at a temperature of 60° C. under a nitrogen stream, and polymerized for 8 hours while stirring at 12 Q rpm, resulting in a solid content of 30% and an average particle size of 1 y! ! An aqueous dispersion of 0.3μ polymer particles was obtained.

Distilled water was added to this aqueous dispersion to make the solid content 10%, and 100 ml of the dispersion was mixed with hydrochloric acid to 6 pl+ as shown in the table below.
A 1% m-xylylenediamine aqueous solution adjusted to δ was added thereto and stirred, and then a 1% glutaraldehyde aqueous solution was added and reacted at 5° C. for 5 hours. After the reaction was completed, the mixture was centrifuged, and the precipitated polymer particles were washed with distilled water to remove unreacted xylylene diamine and glutaraldehyde. The amino groups and aldehyde groups possessed by the obtained water-dispersed polymer particles were quantified. The results are shown in the table.

Next, an example will be shown in which the water-dispersed polymer particles having an aldehyl 1-" group, numbered 2 in the table, are used as a carrier for an immobilized enzyme.

An enzyme aqueous solution prepared by dissolving urease Ig in 1.0+n+ water was added to 100 ml of the polymer particle dispersion, and reacted at 5° C. for 8 hours with stirring. After the reaction is complete, centrifuge the
The precipitated polymer particles were washed with a buffer (pH 7) prepared from 0.1 M dipotassium hydrogen phosphate and 0.1 M potassium dihydrogen phosphate to remove unfixed urease,
This was dispersed again in a buffer solution to obtain an immobilized enzyme in which urease was covalently immobilized on the aldehyde groups of the polymer particles. The amount of urease immobilized in this immobilized enzyme was 22 m++ per gram of polymer particles, and the activity yield, defined as the ratio of the actual activity to the theoretical amount of activity of the immobilized enzyme, was 40%. Ta. Activity yield is 0
．． Using a 3M urea aqueous solution as a substrate, the immobilized enzyme was reacted at 35° ( ) for 10 minutes, the amount of ammonia produced (μmol/min) was determined by hydrochloric acid titration, and the activity was measured. The amount of enzyme was divided by the amount of immobilized enzyme.

Example 2 Polymerization initiator aqueous solution prepared by adding 3 g of acrylic acid, 10 g of styrene, 60 g of ethyl/methacrylate, 1-17 g of methyl methacrylate, and Log acrylonitrile to 400 g of distilled water, and dissolving 0.3 g of potassium persulfate in 10 g of water. was added under a nitrogen stream at a temperature of 70°C, and at 120 rpm.
Polymerization was carried out for 8 hours with stirring to obtain an aqueous dispersion of polymer particles A having a solid content of 20% and an average particle size of 0.3 μm. The polymer particles have free carboxyl groups.

Next, after adding 50 g of distilled water to 50 g of this aqueous dispersion,
8 ml of a 1% m-xylylenediamine aqueous solution whose pl+ was adjusted to 6 with hydrochloric acid was added and stirred, then 5 ml of a 1% glutaraldehyde aqueous solution was added and reacted at 25°C for 4 hours. After the reaction is completed, the precipitated polymer particles are centrifuged, washed with distilled water to remove unreacted xylylene diamine and glutaraldehyde, and dispersed again in distilled water to dissolve the Schiff polymer particles containing free amine groups. Water-dispersed polymer particles B on which a base polymer was deposited were obtained.

Next, when this aqueous dispersion of Polymer B was added to the previous dispersion of the polymer, the polymer particles immediately agglomerated and all precipitated.

Claims (1)

[Claims] (11) A polyamine and a dialdehyde are reacted in an aqueous dispersion of water-dispersed polymer particles, and a ship base of the polyamine and dialdehyde is applied to the surface of the water-dispersed polymer particles. (2) A method for surface modification of water-dispersed polymer particles, characterized in that the water-dispersed polymer particles have an average particle diameter of 0.03 to 2μ. A method for modifying water-dispersed polymer particles according to claim 1.