KR101287546B1 - Method of preparing methacrylate-based polymer using free radical polymerization reaction by visible light photocatalysis - Google Patents

Abstract

The present invention relates to a process for preparing a methacrylate polymer using free radical polymerization, the process comprising the step of irradiating a mixture of a radical initiator, an electron donor, a monomer, a ruthenium dye and a solvent with visible light .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a methacrylate polymer by free radical polymerization using a visible light photocatalyst,

The present invention relates to a method for producing a methacrylate polymer by free radical polymerization using a visible light photocatalyst.

The radical polymer polymerization reaction includes a thermochemical method and a photochemical method. Among them, the thermochemical method starts the polymerization reaction by pyrolysis, which requires a temperature increase, and thus it is difficult to control the polymerization reaction of the polymer.

On the other hand, the photochemical method is advantageous in that it is easy to control the polymerization reaction of the polymer and is easily applied to the thermally unstable monomer. Therefore, various studies have been conducted on such photochemical methods.

Radical polymerization using a photochemical method can be carried out by irradiating an aromatic carbonyl compound (benzoin or a derivative thereof) with light, through the? -Cleavage of the compound, or in the presence of a hydrogen atom donor, Is a method in which light is irradiated to ketones (benzophenone, quinone, etc.) to generate free radicals through bisphenidic separation of aromatic ketones, and the monomers are polymerized using the free radicals.

The light may include UV light and visible light. However, the UV light has a risk that it is expensive to generate and maintain.

Recently, studies on radical polymerization using visible rays which are safe, economical, low risk, and easy to use have been actively conducted. In recent years, heterogeneous semiconductor photocatalysts such as ZnS and CdS which produce radicals by absorbing visible light have been proposed in order to use visible light for radical polymerization. However, the radicals generated by the semiconductor photocatalyst are generally unstable, have little effect, have a low degree of polymerization, and cause a high degree of polydispersity.

The present invention provides a method for producing a methacrylate polymer using a free radical polymerization reaction which is safe and economical and which can control the polymer polymerization reaction.

One embodiment of the present invention provides a process for preparing a methacrylate polymer using free radical polymerization comprising irradiating a mixture of a radical initiator, an electron donor, a monomer, a ruthenium dye and a solvent with visible light.

The ruthenium dye may be a ruthenium (II) polypyridine complex.

The radical initiator may be an alpha -halo ester, a benzyl halide, or a combination thereof, more particularly ethyl 2-bromoisobutyrate, benzyl bromide, or a combination thereof.

The electron donor is used in an amount of 0.25 to 10 moles per 100 moles of the monomer. The ruthenium dye is used in an amount of 0.005 to 0.1 moles per 100 moles of the monomer, Can be used in an amount of 0.25 to 5 mol.

The visible light may be a light having a wavelength of 420 to 645 nm.

The monomer may be selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, 2-ethoxyethyl methacrylate, Lt; / RTI > The electron donor may be N, N-diisopropylethylamine, triethylamine, tripropylamine or a combination thereof. The solvent may also be dimethylformamide, acetonitrile, toluene, or a combination thereof.

Other details of the embodiments of the present invention are included in the following detailed description.

The present invention provides a method for producing a methacrylate-based polymer that is safe, economical, and capable of controlling polymer polymerization reaction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing a yield and a polydispersity according to the visible light irradiation time according to Example 10. FIG.
FIG. 2 is a graph showing the number average molecular weight (Mn) and the weight average molecular weight (Mw) of polymethylmethacrylate prepared according to Examples 11 to 16.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

The present invention relates to a process for preparing a methacrylate polymer using free radical polymerization, and more particularly, to a process for preparing a ruthenium dye as a photocatalyst in a free radical polymerization process.

The method for producing a methacrylate polymer of the present invention includes a step of irradiating a mixture of a radical initiator, an electron donor, a monomer, a ruthenium dye and a solvent with visible light.

The dye may use ruthenium (II) polypyridine complex. Specific examples of the dyes include tris (bipyridine) ruthenium (II) dichloride hexahydrate, tris (bipyridine) ruthenium (II) bis (hexafluorophosphate) Combinations.

The ruthenium dye functions as a photocatalyst, and a reaction formed when light is irradiated to the dye, for example, Ru (bpy) ₃ ²⁺ (bpy: bipyridine) will be described as follows.

Ru (bpy) when irradiated with visible light for ₃ ^2+, Ru * (bpy) ₃ ²⁺ forming, and thus * Ru (bpy) ₃ ²⁺ is formed accept an electron from the electron donor which has a high reducing power Ru ( bpy) ₃ < ^{+ &} gt ;, which is obtained by reducing an initiator to generate a radical, and the monomer is polymerized into a polymer by the radical.

That is, in the production method according to one embodiment of the present invention, when a mixture of a radical initiator, a ruthenium dye, an electron donor, a monomer and a solvent is irradiated with visible light, the ruthenium dye is excited by light, The electrons are received from the donor and reduced. The thus-produced reduced ruthenium dye forms a radical by reducing the initiator, and by this radical the monomer can be polymerized into the polymer .

The radical initiator may be one having a lower standard potential than the reduced ruthenium (I) polypyridine complex. Examples of the radical initiator may be? -Haloester, benzyl halide, or a combination thereof, and specific examples include ethyl 2-bromoisobutyrate, benzyl bromide, or a combination thereof. The use of an? -Haloester as a radical initiator is preferable because the yield of polymer production can be further improved.

The monomer may be selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, 2-ethoxyethyl methacrylate, Lt; / RTI >

The electron donor may be N, N-diisopropylethylamine, triethylamine, tripropylamine or a combination thereof, and the solvent may be dimethylformamide, acetonitrile, toluene or combinations thereof.

In the above production process, the electron donor is preferably used in an amount of 0.25 to 10 moles per 100 moles of the monomer. The ruthenium dye is preferably used in an amount of 0.005 to 0.1 mole based on 100 moles of the monomer. The radical initiator is preferably used in an amount of 0.25 to 5 moles per 100 moles of the monomer. When the content of the electron donor, ruthenium dye and radical initiator is within the above range, the yield of the polymer to be produced can be further increased.

In particular, when the content of the electron donor is less than 0.25 mol, the yield of the polymer is undesirably decreased, and even if the molar content is increased beyond 10 mol, there is no further increase in the yield, so that it is not necessary to use an electron donor in a larger amount. When the amount of the ruthenium dye and the amount of the radical initiator is less than the above range, the yield is lowered, and even when the amount exceeds the above range, there is no further increase in the yield, so that it is not necessary to use the ruthenium dye in an excess amount.

In particular, the molar ratio of the monomer, the radical initiator, the ruthenium dye and the electron former is preferably 100: 0.5 to 2.5: 0.01 to 0.05: 0.5 to 5.

In addition, the solvent may be used in an appropriate volume ratio with the monomer.

In the production method of the present invention, the step of irradiating the visible light can be carried out by irradiating visible light having a wavelength of 420 to 645 nm. When light exceeding 645 nm is irradiated, the ruthenium dye does not absorb light and the polymer polymerization reaction does not occur, which is not preferable. In addition, the use of visible light having the above-mentioned wavelength is economical because expensive additional equipment such as an ultraviolet lamp is not required. At this time, the visible light irradiation time is not significant, and can be carried out for, for example, 4 to 20 hours.

The step of irradiating the visible light can be performed by using a Xe-arc lamp, a fluorescent lamp, or the like.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

(Examples 1 to 5)

-0.82 V_NHE in 디메틸포름아미드) 라디칼 개시제, 트리스(비피리딘) 루테늄(II) 디클로라이드 헥사하이드레이트 (Tris(bipyridine) ruthenium(II) dichloride hexahydrate, (Ru(bpy)₃Cl₂·6H₂O)) 루테늄 염료, N,N-디이소프로필에틸아민 전자 주개 및 디메틸포름아미드 용매의 혼합물에, 가시광선을 조사하여 라디칼 중합 반응을 실시하였다.Methyl methacrylate (MMA) monomer (20 mmol), ethyl 2-bromoisobutyrate (EBiB, E ⁰

-0.82 V _NHE in dimethylformamide), a radical initiator, tris (bipyridine) ruthenium (II) dichloride hexahydrate, (Ru (bpy) ₃ Cl ₂ .6H ₂ O) ) A ruthenium dye, a N, N-diisopropylethylamine electron donor and a mixture of a dimethylformamide solvent were irradiated with visible light to perform a radical polymerization reaction.

At this time, the visible light irradiation process was performed by irradiating light for 4 hours at room temperature using a Xe-arc lamp having a wavelength range of 420-645 nm and a strength of 25 mW / cm 2.

The molar ratio of the monomer, the radical initiator, the ruthenium dye and the electron former was controlled as shown in Table 1, wherein the ratio of the monomer to the solvent was 1: 1 by volume.

Polymethyl methacrylate was prepared by the above polymerization process.

(Example 6)

The procedure of Example 5 was repeated except that the visible light irradiation step was performed for 20 hours.

(Example 7)

The procedure of Example 5 was repeated, except that benzyl bromide was used as a radical initiator.

(Example 8)

The visible light irradiation process was carried out at room temperature using a Xe-arc lamp having a bandpass filter, and had a wavelength range of 450 (± 20) nm and a intensity of 4 mW / cm 2 (tris (bipyridine) ruthenium (II )) For 4 hours in the same manner as in Example 5. The results are shown in Table 1. < tb > < TABLE >

(Example 9)

Except that the visible light irradiation process was carried out by using a 27-W fluorescent lamp at room temperature and irradiating light having a wavelength range of 400 to 700 nm and a light intensity of 2 mW / cm 2 for 4 hours, Respectively.

(Comparative Example 1)

(MMA) monomer (20 mmol), tris (bipyridine) ruthenium (II) dichloride hexahydrate (Tris (bipyridine) ruthenium (II) dichloride hexahydrate, (Ru (bpy) ₃ Cl ₂ .6H ₂ O) ) A ruthenium dye, a N, N-diisopropylethylamine electron donor and a mixture of a dimethylformamide solvent were irradiated with visible light to perform a radical polymerization reaction. The molar ratios of the monomers, ruthenium dyes, and electrons were controlled as shown in Table 1, wherein the ratio of monomer to solvent was 1: 1 by volume.

At this time, the visible light irradiation process was performed by irradiating light for 4 hours at room temperature using a Xe-arc lamp having a wavelength range of 420-645 nm and a strength of 25 mW / cm 2.

(Comparative Example 2)

-0.82 V_NHE in 디메틸포름아미드) 라디칼 개시제, 트리스(비피리딘) 루테늄(II) 디클로라이드 헥사하이드레이트 (Tris(bipyridine) ruthenium(II) dichloride hexahydrate, (Ru(bpy)3Cl2·6H2O)) 루테늄 염료 및 디메틸포름아미드 용매의 혼합물에, 가시광선을 조사하여 라디칼 중합 반응을 실시하였다.Methyl methacrylate (MMA) monomer (20 mmol), ethyl 2-bromoisobutyrate (EBiB, E ⁰

-0.82 V _NHE in dimethylformamide) a radical initiator, tris (bipyridine) ruthenium (II) dichloride hexahydrate (Tris (bipyridine) ruthenium (II) dichloride hexahydrate, (Ru (bpy) 3Cl2 · 6H2O)) and ruthenium dye Dimethylformamide solvent was irradiated with visible light to perform radical polymerization reaction.

The molar ratios of the monomer, radical initiator and ruthenium dye were controlled as shown in Table 1, wherein the ratio of monomer to solvent was 1: 1 by volume.

At this time, the visible light irradiation process was performed by irradiating light for 4 hours at room temperature using a Xe-arc lamp having a wavelength range of 420-645 nm and a strength of 25 mW / cm 2.

(Comparative Example 3)

-0.82 V_NHE in 디메틸포름아미드) 라디칼 개시제, 트리스(비피리딘) 루테늄(II) 디클로라이드 헥사하이드레이트 (Tris(bipyridine) ruthenium(II) dichloride hexahydrate, (Ru(bpy)₃Cl₂·6H₂O)) 루테늄 염료, N,N-디이소프로필에틸아민 전자 주개 및 디메틸포름아미드 용매의 혼합물에 대하여 중합 반응을 실시하였다. 상기 모노머, 라디칼 개시제, 루테늄 염료 및 전자 주개의 몰비는 하기 표 1에 나타낸 것과 같이 조절하였으며, 이때 모노머와 용매의 비율은 1:1 부피비로 하였다.Methyl methacrylate (MMA) monomer (20 mmol), ethyl 2-bromoisobutyrate (EBiB, E ⁰

-0.82 V _NHE in dimethylformamide), a radical initiator, tris (bipyridine) ruthenium (II) dichloride hexahydrate, (Ru (bpy) ₃ Cl ₂ .6H ₂ O) ) Ruthenium dye, N, N-diisopropylethylamine electron donor and a dimethylformamide solvent. The molar ratio of the monomer, the radical initiator, the ruthenium dye and the electron former was controlled as shown in Table 1, wherein the ratio of the monomer to the solvent was 1: 1 by volume.

(Comparative Example 4)

-0.82 V_NHE in 디메틸포름아미드) 라디칼 개시제, N,N-디이소프로필에틸아민 전자 주개 및 디메틸포름아미드 용매의 혼합물에, 가시광선을 조사하여 라디칼 중합 반응을 실시하였다. 상기 모노머, 라디칼 개시제 및 전자 주개의 몰비는 하기 표 1에 나타낸 것과 같이 조절하였으며, 이때 모노머와 용매의 비율은 1:1 부피비로 하였다.Methyl methacrylate (MMA) monomer (20 mmol), ethyl 2-bromoisobutyrate (EBiB, E ⁰

-0.82 V _NHE in dimethylformamide) Radical polymerization was carried out by irradiating a mixture of radical initiator, N, N-diisopropylethylamine electron donor and dimethylformamide solvent with visible light. The molar ratios of the monomers, radical initiators and electron precursors were controlled as shown in Table 1, wherein the ratio of monomer to solvent was 1: 1 by volume.

At this time, the visible light irradiation process was performed by irradiating light for 4 hours at room temperature using a Xe-arc lamp having a wavelength range of 420-645 nm and a strength of 25 mW / cm 2.

(Comparative Example 5)

The procedure of Example 1 was repeated, except that the molar ratios of the monomers, the initiator, the ruthenium dye and the electron former were changed as shown in Table 1 below.

The processes of Examples 1 to 9 and Comparative Examples 1 to 5 were carried out twice each, and the average of the yields of the obtained polymethyl methacrylate was determined. The results are shown in the following Table 1. The polydispersity index (PDI = Mw / Mn) of the prepared polymethylmethacrylate was measured and the results are shown in Table 1. The results are shown in Table 1 below.

Composition ratio
(Monomer: initiator: ruthenium dye: electron donor, molar ratio) Mn Mw / Mn (PDI) yield(%) Comparative Example 1 200: 0: 0.02: 5 - - 0 Comparative Example 2 200: 1: 0.02: 0 - - 0 Comparative Example 3 200: 1: 0.02: 5 - - 0 Comparative Example 4 200: 1: 0: 5 - - 0 Example 1 200: 1: 0.1: 5 42400 2.0 25 Example 2 200: 1: 0.02: 5 56400 2.0 23 Example 3 200: 5: 0.02: 5 38900 2.1 31 Comparative Example 5 200: 1: 0.02: 1 58000 2.0 2 Example 4 200: 1: 0.02: 10 36500 2.1 30 Example 5 200: 5: 0.02: 10 26400 2.0 34 Example 6 200: 5: 0.02: 10 25900 2.0 76 Example 7 200: 5: 0.02: 10 37100 2.7 12 Example 8 200: 5: 0.02: 10 33500 2.0 16 Example 9 200: 5: 0.02: 10 30600 1.7 39

As shown in Table 1 above, in all of Examples 1 to 9, the polydispersity index was about 2.0. From this result, it can be seen that the visible light-induced radical polymerization gives a polymer dispersion having a favorable degree.

As the amount of ruthenium dye used increases (compared with Example 1 and Example 2), the yield is somewhat increased. In addition, when the amount of the initiator used is increased (comparison between Example 3 and Example 2), it is understood that the yield is remarkably improved.

In addition, when the content of the electron donor is too small (Comparative Example 5), the yield is remarkably reduced. Also, in the case of Comparative Examples 1 to 4 in which no initiator or electron donor was used, no light was irradiated, or no ruthenium dye was used, the yield was 0, that is, no polymer was formed.

The number average molecular weight (Mn) of the product, polymethyl methacrylate, decreased with increasing electron content. This is presumably because N, N-diisopropylethylamine used as an electron donor acts not only as an electron donor but also as a hydrogen-atom donor to stop the polymerization reaction. As a result, the molecular weight can be controlled by adjusting the concentration of the electron donor. In addition, in the case of Example 8 in which light having a low wavelength range and sensitivity was irradiated, the yield was lowered because the photon flux was somewhat lowered. From the results of Example 9, it can be seen that the radical polymerization reaction occurs appropriately even when the light is irradiated with weaker light than a general visible light ray.

(Example 10)

-0.82 V_NHE in DMF) 개시제, 트리스(비피리딘) 루테늄(II) 디클로라이드 헥사하이드레이트 (Tris(bipyridine) ruthenium(II) dichloride hexahydrate, (Ru(bpy)₃Cl₂·6H₂O)) 루테늄 염료, N,N-디이소프로필에틸아민 전자 주개 및 디메틸포름아미드 용매 존재 하에서, 가시광선을 조사하여 라디칼 중합 반응을 실시하였다. [모노머]:[개시제]:[루테늄 염료]:[전자 주개]의 조성비는 200:5:0.02:10 몰비로 하였고, 모노머와 디메틸포름아미드의 사용량은 1 : 1 부피비로 하였다.Methyl methacrylate (MMA) monomer (40 mmol), ethyl 2-bromoisobutyrate (EBiB, E ⁰

-0.82 V _NHE in DMF) ruthenium (II) dichloride hexahydrate, (Ru (bpy) ₃ Cl ₂ .6H ₂ O)) ruthenium dyes (tris (bipyridine) ruthenium , N, N-diisopropylethylamine electron donor and a dimethylformamide solvent, a radical polymerization reaction was carried out by irradiation of visible light. The composition ratio of [monomer]: [initiator]: [ruthenium dye]: [electron donor] was 200: 5: 0.02: 10, and the amount of monomer and dimethylformamide was 1: 1.

At this time, the visible light irradiation process was performed by irradiating light at room temperature with a Xe-arc lamp having a wavelength range of 420-645 nm and a intensity of 25 mW / cm 2, Turn-off (Fig. 1). The yield and PDI of polymethylmethacrylate produced every 2 hours were measured, and the results are shown in FIG.

As shown in FIG. 1, the yield was gradually increased as the time for irradiating light increased, and it was clear that the yield did not increase when the light was turned off. From this result, it can be seen that the polymer preparation process of Example 10 can control the generation of active radicals which lead to polymer production by a simple operation of turning on and off the light. In addition, the PDI gradually increased (from about 1.9 to about 2.4) as the turn-on and turn-off processes were repeated, which means that the molecular weight distribution is broadened as the polymer polymerization reaction is repeated.

(Examples 11 to 16)

Except that the molar ratio of the monomer (20 mmol), the initiator, the ruthenium dye and the electron former was changed as shown in Table 2 below.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) of polymethyl methacrylate prepared according to Examples 11 to 16 were measured, and the results are shown in FIG.

Composition ratio
(Monomer: initiator: ruthenium dye: electron donor, molar ratio) Mw Mn Example 11 200: 10: 0.02: 10 55100 24700 Example 12 200: 5: 0.02: 10 59600 26500 Example 13 200: 2.5: 0.02: 10 64000 29700 Example 14 200: 1.25: 0.02: 10 73100 32000 Example 15 200: 0.5: 0.02: 10 101000 39000 Example 16 200: 0.25: 0.02: 10 144200 52500

As shown in FIG. 2 and Table 2, when the mixing ratio of the monomer and the initiator is controlled, the weight average molecular weight and the number average molecular weight of the produced polymethyl methacrylate can be controlled. Therefore, the molecular weight of the polymethylmethacrylate can be easily controlled as desired by adjusting the mixing ratio of the monomer and the initiator.

(Examples 17 to 23)

Radical polymerization was carried out by irradiating visible light to 10 mmol of the monomer shown in Table 2, 0.25 mmol of initiator, 0.01 mmol of ruthenium dye, 0.5 mmol of electron donor and dimethylformamide. The amount of the monomer and dimethylformamide used was 1: 1 by volume. The visible light irradiation process was performed by irradiating light having a wavelength range of 420 to 645 nm and having a intensity of 25 mW / cm 2 for the time shown in Table 3 below. The products produced by the radical polymerization reaction are shown in Table 3 below.

In order to separate the polymer prepared from the products according to Examples 17 to 23 and the unreacted monomer, the produced product was precipitated in methanol, and the yield was measured. The results are shown in Table 3 below. When the produced product is immersed in methanol, the polymer is not dissolved in methanol, and the monomers can be dissolved in methanol and separated.

Monomer product Investigation time M _n PDI ( M _w / M _n ) yield Example 17

24 25100 2.0 80% Example 18

24 31300 2.0 75% Example 19

24 80200 1.7 74% Example 20

24 34200 2.1 65% Example 21

24 55600 1.8 70% Example 22

12 41700 3.8 86% Example 23

12 42300 3.5 83%

As shown in Table 3, since the polyacrylate was produced in a yield of about 60 to 90% irrespective of the type of the methacrylate monomer, it can be seen that the radical polymerization reaction was properly performed. Furthermore, from the results shown in the above Table 3, it can be seen that Examples 22 and 23 using methacrylate having an electron-withdrawing group are examples of the methacrylate having an electron-donating group The reaction rate is faster than that of 17 to 21.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (11)

A step of irradiating a visible light to a mixture of a radical initiator, an electron donor, a monomer, a ruthenium dye and a solvent,
The content of the electron donor is 2.5 to 10 moles per 100 moles of the monomer,
The radical initiator may be ethyl 2-bromoisobutyrate, benzyl bromide or a combination thereof
A method for producing a methacrylate polymer by free radical polymerization. The method according to claim 1,
Wherein the ruthenium dye is a ruthenium (II) polypyridine complex. delete delete delete The method according to claim 1,
Wherein the content of the ruthenium dye is 0.005 to 0.1 mole per 100 moles of the monomer. The method according to claim 1,
Wherein the content of the radical initiator is 0.25 to 5 moles with respect to 100 moles of the monomer. The method according to claim 1,
Wherein the visible light is a light having a wavelength of 420 to 645 nm. The method according to claim 1,
The monomer may be selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, 2-ethoxyethyl methacrylate, By weight based on the total weight of the methacrylate-based polymer. The method according to claim 1,
Wherein the electron donor is N, N-diisopropylethylamine, triethylamine, tripropylamine or a combination thereof. The method according to claim 1,
Wherein the solvent is dimethylformamide, acetonitrile, toluene or a combination thereof.

Images