CS258167B1 - Block copolymers consisting of! of medium hydrophilic blocks of dimethylaminoethyl methacrylate structural units and strong hydrophilic blocks of methacryloyloxyethyl dimethylalkylammonium salts and a process for their preparation - Google Patents

Abstract

The solution relates to block copolymers of dimethylaminoethyl methacrylate with methacryloyloxyethyldimethylammonium salts and a method for their preparation. These block copolymers consist of moderately hydrophilic blocks based on 2-dimethylaminoethyl methacrylate structural units and strongly hydrophilic blocks based on methacryloyloxymethyldimethalkyl-' ammonium salts. The method of preparation consists in treating poly(2-dimethylaminoethyl methacrylate) with a suitable alkylating agent in solutions of lower alcohols selected from the group of ethanol, methanol, propanol and isopropanol or their mixtures with water at a temperature of -20 °C to 60 °C. The copolymers can be used to prevent fogging of glass and plastic products.

Description

The invention relates to block copolymers of dimethylaminoethyl methacrylate with methacryloyloxyethyldimethylalkylammonium salts and a method for their preparation.

According to the current methods of preparation, block copolymers are obtained by the technique of anionic polymerization with living ends, in which, after the polymerization of the first monomer, a second monomer is added to the reaction mixture, which polymerizes on the living ends of the polymer prepared in the first stage; for example, the synthesis of a triblock of the BAB type poly(methyl methacrylate)-block-poly(styrene)-block-poly(methyl methacrylate), in which styrene is first polymerized by the action of sodium dihydronaphthylide and in the second stage, methyl methacrylate is polymerized on both living ends of the macromolecules of the anionic poly(styrene).

Another method is the chemical reaction of two different polymers terminated with groups suitable for mutual reaction, for example, the preparation of a block copolymer of polystyrene terminated with -OH groups and polyacrylate terminated with a carboxyl group. Polystyrene with terminal hydroxy groups can be prepared by polymerization of styrene by the action of sodium dihydronaphthylide, the chain growth of which was terminated by ethylene oxide; polyacrylate with terminal -COOH groups can be prepared, for example, by radical polymerization with an azo initiator containing a -COOH group. They can be prepared by chemical, or by radiation grafting of monomers or their mixtures onto the starting polymer, for example by grafting acrylic monomers and their mixtures onto active cellulose using initiation using redox systems or by radiation grafting of styrene onto polyethylene, etc. This grafting can also be performed on finished products with a suitable arrangement, and thus, for example, materials suitable for further chemical modifications (preparation of ion exchange capillaries, etc.) can be prepared from polyethylene capillaries filled with styrene by the effect of gamma radiation.

The newly formed polymer has a comb-like or networked structure characterized by the fact that side chains or networks formed from the newly grafted monomer or their mixtures are bound to the basic skeleton of the original polymer.

In general, it can be stated that block copolymers prepared by any of the above methods can be used as such or after chemical modification, which may possibly further deepen the differences in the polarity of the individual blocks.

In the triblock copolymer poly(methyl methacrylate)-block-poly(styrene)-block-poly(methyl methacrylate)-block-poly(styrene)-block-poly(methyl methacrylate) ester groups can be converted to hydrophilic carboxyl groups by hydrolysis. Similarly, in the block copolymer type AB poly(methyl methacrylate)-block-poly(pivaloyloxyethyl methacrylate) pivaloyl groups can be quantitatively removed by selective hydrolysis to prepare poly(methyl methacrylate)-block-poly(2-hydroxyethyl methacrylate) with significant differences in block polarity.

Block copolymers are used mainly in applications where the different character of the individual blocks, for example polarity, can be used, i.e. especially at phase interfaces (stabilizers, compatibilizers, dispersants in polymer mixtures) and as adhesives between otherwise incompatible polymer surfaces, etc.

From the above it follows that the current preparation of block copolymers containing moderately to strongly hydrophilic groups is usually carried out in several stages. In the first stage, a basic more hydrophobic block is usually formed by anionic polymerization, onto which a more polar monomer is polymerized, which is usually a precursor for the preparation of moderately to strongly hydrophilic groups, which are formed by chemical modification.

If hydrophilic groups are formed from more or less non-polar groups of homopolymers (not block copolymers), for example by partial hydrolysis of poly(methyl methacrylates) and other polymer esters, polymers with a more or less random (statistical) distribution of hydrophilic groups along the polymer backbone are formed, and it is not uncommon for polymers to not undergo quantitative conversion due to repulsive forces between the similarly charged newly formed groups and the hydrophilizing agents.

We have found that the homopolymer poly(2-dimethylaminoethyl methacrylate) (hereinafter referred to as PDAEM) with different tacticity of the polymer matrix during the hydrophilization reaction in a suitably selected reaction environment is quaternized by the action of alkylating agents such that the preferential reaction of the quaternizing agent with the tertiary amine group occurs, which is directly related to the group in which the quaternization has already occurred. The reaction course has the character of a zipper reaction, proceeding from the first quaternary ammonium group along the polymer skeleton until the alkylating agent is exhausted or, with a sufficient or excess amount of the agent, until the quantitative conversion of tertiary amino groups to quaternary ammonium ions.

This results in block copolymers according to the invention, characterized in that they consist of moderately hydrophilic blocks based on 2-dimethylaminoethyl methacrylate structural units and strongly hydrophilic blocks based on methacryloyloxyethyldimethylalkylammonium salts of the general formula I — CH,

CHi 3 ^CH 2 - C

COO(CH ₂ ) ₂ N(CH ₃ ) ₂

CH, - C ² I

COO(CH ₂ ) ₂ N(CH ₃ ) ₂ a-, (I) where

R is -CH ₃ , -C ₂ H ₅ , -C ₃ H _? , -C^Hg, -C ₅ H _n , -C _g H ₁₃ , - ΰ _γ Η ₁₅ , -C _g H ₁₇ , iso -CjH,,, iso -C ₄ Hg and

-CH ,CH ₂ OH, έη _ί +Ž ^r m _i = P, where έ _x p = degree of polymerization, e.g. 10,000 and _m — ₊ = /0.1/.

The method of preparing block polymers according to the invention consists in that poly(2-dimethylaminoethyl methacrylate) of the general formula II ^ch 2 - v

CH, I 3 (II) where coo(ch ₂ ) ₂ n(ch ₃ ) ₂ = p, e.g. 10,000, with different tacticity is treated with an alkylating agent of general formula III

Rl (III) where

R — — CH ₃ , — CjHj , —CgH ₇ , —C^Hg , —C,.H ₃₃ , — C _g H^ ₃ , —C ₇ H _3g , —CgH^y, iso —CgH ₇ , iso —C^Hg and -CH ₂ CH ₂ OH in solutions of lower alcohols selected from the group of ethanol, methanol, propanol and isopropanol or their mixtures with water at a temperature of -20 °C to 60 °C.

For synthesis, it is first necessary to prepare PDAEM by one of the previously described methods (anionic or radical with molecular weight M = 1-1.10® (e.g. M. Přádný, S. Ševčík, P. Vlček: Polymer Bull., 12, 337 (1984); M. Přádný, S. Ševčík: Makromol. Chem. 186, 111-121 (1985). The condition for the formation of block copolymers is the use of lower alcohols (i.e. methanol, ethanol, propanol, isopropanol) or their mixtures with water as solvents. Any ratio of alcohol and water in which PDAEM is still soluble can be used as solvents. At water concentrations higher than about 80 wt. % (depending on the alcohol), PDAEM precipitates.

The reaction proceeds quantitatively, so that the amount of charged quaternary comonomer in the final copolymer corresponds to the amount of alkylating agent added to the reaction mixture. Thus, block copolymers with any ratio of dimethylaminoethyl methacrylate to methycryloyloxyethyldimethylalkylammonium iodide can be synthesized by the method described above.

The described reaction can be carried out in a wide temperature range from -20 °C to 60 °C without pressure, at higher temperatures it is necessary to use increased pressures. Reaction times also vary depending on the temperature, with increasing temperature the reaction times decrease, but the risk of hydrolysis of alkylating agents increases. The recommended temperature is therefore 25 °C. Reaction times are given for individual alkylating agents in the examples.

When using other solvents as the reaction medium, e.g. acetone, tetrahydrofuran or their mixtures with water, copolymers with a predominantly block structure are not formed.

The microstructure of copolymers (block or statistical microstructure) was determined by the previously described method (M. Přádný, S. Ševčík: Makromol. Chem., in press; M. Přádný, I.

Kminek, S. Ševčík: Polymer Bull., 16, 195-200 (1986)), based on potentiometric titration of copolymers in aqueous ethanolic solution. Aqueous ethanolic solutions were chosen for their good ability to dissolve the described copolymers. Titration curves, i.e. the dependence of the pH of copolymer solutions on the amount of added 0.1 N hydrochloric acid, were measured on a TTTlc titrator connected to an ABU 12 automatic burette and a Titrigraph SBR 2c recorder (all Radiometer Copenhagen).

These dependencies were then processed into modified titration curves (M. Přádný, S.

Ševčík: Makromol. Chem. 186, 111-121 (1985)), according to which the block or statistical structure of the obtained copolymers was inferred. The modified titration curve is the dependence of the apparent dissociation constant (K ) on the degree of ionization of tertiary amino groups (alpha). app

The method is based on the fact that the modified titration curves of PDAEM and copolymers of dimethylaminoethyl methacrylate with methacryloyloxyethyltrimethylammonium iodide or methyl sulfate obtained by radical copolymerization, i.e., a random copolymer, are significantly different (Fig. 1). Fig. 1 shows the modified titration curves of the PDAEM homopolymer (1) and the random copolymer poly(2-dimethylaminoethyl methacrylate-co-methacryloyloxyethyltrimethylammonium iodide) (2) with a content of 80 mol. % quaternary ammonium comonomer. Titrations were performed in an aqueous ethanolic solvent, the water content was 43 wt. %, the concentration of dimethylaminoethyl methacrylate structural units was 4.5 mmol/1,000 g. On the modified PDAEM titration curve there is a significant minimum around the ionization degrees of 0.6, whereas on the modified titration curve of the random copolymer there is no minimum, the curve is constantly increasing.

Copolymers prepared by quaternization of PDAEM in alcoholic solutions behave potentiometrically similar to the PDAEM homopolymer (Fig. 2), i.e. minima occur on the modified titration curves. Fig. 2 shows the modified titration curves of block copolymers of poly(2-dimethylaminoethyl methacrylate-block-methacryloyloxyethyltrimethylammonium iodides) prepared by quaternization of PDAEM in various aqueous ethanolic solutions with different dimethylaminoethyl methacrylate contents.

Reaction medium (water content in the mixture with ethanol, wt. %) Content of 2-dimethylaminoethyl methacrylate in the resulting copolymer, wt. % Curve 4 82.2 1 13.9 2 43 82.4 3 35.8 4 7.4 5 64 35.6 6 6.8 7

the concentration of dimethylaminoethyl methacrylate structural units was 4.5 mmol/1,000 g.

On the other hand, copolymers prepared by partial quaternization in non-alcoholic solutions behave potentiometrically similar to the random copolymer dimethylaminoethyl methacrylate - methacryloyloxyethyltrimethylammonium iodide, and their structure is therefore also statistical. Figure 3 shows the modified titration curves of the random copolymers poly(2-dimethylaminoethyl methacrylate-co-methacryloyloxyethyltrimethylammonium iodides) prepared by quaternization of PDAEM in tetrahydrofuran (1), tetrahydrofuran-water mixture (1:1 wt.) (2), acetone (3), acetone-water mixture (1:1 wt.) (4). The concentration of the structural units of dimethylaminoethyl methacrylate was 4.5 mmol/1 000 g.

The potentiometric titration method can distinguish the microstructure of copolymers with a wide range of quaternary ammonium comonomer content, as can be seen from Fig. 2, i.e. there are minima on the modified titration curves of all these block copolymers.

As additional evidence that the copolymers synthesized in alcoholic solutions are predominantly block, NMR spectroscopy was used; the spectra of copolymers prepared by copolymerization and quaternization in alcoholic solutions differed considerably. The spectrum of the random copolymers was significantly split in contrast to the block copolymers.

The block copolymers in powder form were obtained by evaporation of the solvent after the reaction. It is advantageous to redissolve the copolymers in the desired solvent (e.g. water-ethanol mixtures) soon after drying, as dissolution is difficult (but possible) after a longer period of time (1 week).

If counterions other than iodides are required, block copolymers in solution can be modified by ion exchange.

Solutions of the presented block copolymers are, unlike statistical copolymers, considerably viscous, at higher concentrations (depending on the solvent and the number of quaternary ammonium groups in the copolymers) the solutions have thixotropic properties. This property can be used in applications such as preventing fogging of windows in homes, cars, optical instruments (telescopes), glasses, gas mask visors, etc. The products do not have to be made of glass, but also of plastics, such as polymethyl methacrylate, polystyrene, polyvinyl chloride.

Block copolymers of the described type are not hygroscopic, but they absorb water during condensation of water vapor (the copolymers are well soluble in water). Due to the thixotropic properties of concentrated solutions, the polymer film does not run down.

The subject matter of the invention is illustrated by examples.

Example

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-methacryloyloxyethyltrimethylammonium iodide) (hereinafter referred to as Kl)

To 100 g of PDAEM solution in ethanol-water mixture (43 wt. % water) with a concentration of 1.5 wt. % structural units was added rapidly (within 3 s) with intensive shaking 0.677 g of methyl iodide dissolved in 50 g of the same aqueous-ethanolic solvent. After two days at 25 °C the mixture was evaporated to dryness and the theoretical amount of copolymers Kl was obtained. The quaternary comonomer content in the copolymers was 50 mol. %, the copolymer had a predominantly block structure.

Example 2

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylethylammonium iodide) (hereinafter referred to as K2)

Copolymer K2 was prepared in an analogous manner to copolymer K1, but ethyl iodide was used instead of methyl iodide.

and

At 25 °C, the quantitative course of the reaction was determined after 3 days.

Example 3

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylpropylammonium iodide) (hereinafter referred to as K3)

Copolymer K3 was prepared in an analogous manner to copolymer KI, but propyl iodide was used instead of methyl iodide. After 5 days at 25 °C, the quantitative course of the reaction was determined.

Attached

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylbutylammonium iodide) (hereinafter referred to as K4)

Copolymer K4 was prepared in an analogous manner to copolymer K1, but instead of methyl iodide, butyl iodide was used. At 25 °C, the quantitative course of the reaction was determined after 7 days.

Example 5

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylamyl ammonium iodide) (hereinafter referred to as K5)

Copolymer K5 was prepared in an analogous manner to copolymer K1, but amyl iodide was used instead of methyl iodide. The quantitative course of the reaction was determined after 7 days at 25 °C.

Example

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylhexylammonium iodide) (hereinafter referred to as K6)

Copolymer K6 was prepared in an analogous manner to copolymer K1, but hexyl iodide was used instead of methyl iodide. At 25 °C, the quantitative course of the reaction was determined after 7 days.

Example?

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylheptylammonium iodide) (hereinafter referred to as K7)

Copolymer K7 was prepared in an analogous manner to copolymer K1, but heptyl iodide was used instead of methyl iodide. The quantitative course of the reaction was determined after 7 days at 25 °C.

Example 8

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethylammonium iodide) (hereinafter referred to as K8)

Copolymer K8 was prepared in an analogous manner to copolymer K1, but octyl iodide was used instead of methyl iodide. The quantitative course of the reaction was determined after 7 days at 25 °C.

Example 9

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethyl isopropylammonium iodide) (hereinafter referred to as K9)

Copolymer K9 was prepared in an analogous manner to copolymer K1, but isopropyl iodide was used instead of methyl iodide. The quantitative course of the reaction was determined after 7 days at 25 °C.

Example 10

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethyl isobutylammonium iodide) (hereinafter referred to as K10)

Copolymer K10 was prepared in an analogous manner to copolymer kl, but isobutyl iodide was used instead of methyl iodide. At 25 °C, the quantitative course of the reaction was determined after 7 days

Example 11

Block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethyl 2-hydroxyethylammonium iodide) (hereinafter referred to as Kil)

Copolymer Kil was prepared in an analogous manner to copolymer Kl, but 2-iodoethanol was used instead of methyl iodide. The quantitative course of the reaction was determined after 7 days at 25 °C.

Example 12 to 22

The block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethyl kylammonium iodide), where alkyl is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, isopropyl, isobutyl and 2-hydroxyethyl, can also be prepared in the same way as in Examples 1-11, but instead of the ethanol-water solvent, any methanol-water mixture is used.

Example 23 to 33

The block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethyl alkylammonium iodide), where alkyl is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, isopropyl, isobutyl and 2-hydroxyethyl, can also be prepared in the same way as in Examples 1-11, but instead of the ethanol-water solvent, any propanol-water mixture is used.

Example 34 to 44

The block copolymer poly(2-dimethylaminoethyl methacrylate)-block-poly(methacryloyloxyethyldimethyl alkylammonium iodide), where alkyl is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, isopropyl, isobutyl and 2-hydroxyethyl, can also be prepared in the same way as in Examples 1-11, but instead of the ethanol-water solvent, any isopropanol (2-propano)-water mixture is used.

Claims (2)

SUBJECT OF THE INVENTION Block copolymers consisting of medium hydrophilic blocks of 2-dimethylaminoethyl methacrylate units and strongly hydrophilic blocks of methacryloyloxyethyldimethylalkylammonium salts of the general formula I -t <r ^H 3 CH - C ² I COO _{(CH2) 2N (CH3) 2} CHI ³ CH - C ² 1 3Γ 4., COO (CH ₂ ) ₂ γ (CH (I)) 3 '2 where R - -CH ^, ^ 2 ^ 5 ^_ ^ 3 ^ 5 / ”^ 5 ^ 11 *” ^ 6 ^ 13 ^ř * ”^ 7 ^ 15 * *” ^ 8 ^ 17 * iso —C H Hg and -CH ₂ CH ₂ OH, ⁿ i ⁺ P P kde where P polymer polymerization degree ranging from 100 to 20,000 and ^{m m} £ ^{m + + n n} <= <0 ₍ 1). 2. A method of preparing block copolymers corresponded according to claim 1, characterized in that poly (2-dimethylaminoethyl) of formula II CH / ⁿ i ^{+ m} ^ i (II) COO (CH ₂ ) ₂ N (CH ₃ ) ₂ wherein? 4? +? M _i = p, wherein p = polymerization degree in the range of from 100 to 20,000 is treated with an alkylation sensor of formula III R 1 (III) wherein R = -CH ₃ , -CH ₂ H ₅ , -C ₃ H _{? C4} Hg -CgH ^, -CgH _{13, -C?} H ₁₅ , -C ₈ H ₁₇ , iso -C ₁₁ H ₁₀ , iso -C ₄ H ₉ , and -CH ₂ CH ₂ OH in lower alcohol pitches selected from ethanol, methanol, propanol, and isopropanol, or mixtures thereof with water.