KR900003910B1 - Polymerization by using bissiloxane of polymerization intiator - Google Patents

Abstract

Homopolymer or triblock copolymer is polymerized by using bissiloxane polymn. initiator of formula (I) and a catalyst is a solvent. Pref. the homopolymer is methacrylate, methylmethacrylate, butylmethacrylate, arylmethacrylate or acrylonitrile. Pref. the catalyst is tris (dimethyl amino) sulfonium bifluoride, tris (dimethy amino) sulfoniam difluorotrimethyl siliconate or kaliumbifluoride., the solvent is THF or acetonitrile. In the formula, R and R' are each selected from methyl, ethyl, propyl, isopropyle, n-butyl, isobutyl, ter-butyl, pentyl, 2-methylbutyl or 3-methylbutyl; n= 0-2

Description

Method for preparing polymer using bissiloxane polymerization initiator

The present invention relates to a production method for polymerizing an α, β-unsaturated hydrocarbon compound using a bissiloxane polymerization initiator represented by general formula (I).

In general formula (I), R is 5 or less carbon atoms, such as a linear or branched aliphatic hydrocarbon, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, 2-methylbutyl, 3-methylbutyl, etc. Aliphatic hydrocarbon group. Preferably, 4 or less carbon atoms are preferable. R 'is the same as R and n is an integer from 0 to 2.

The present invention is filed separately from Application No. 87-10694, filed Sep. 26, 1987, and the preparation method for the bissiloxane polymerization initiator of general formula (I) used in the present invention is described in detail in the same application. Doing.

The bissiloxane polymerization initiator used in the present invention is a compound that is usefully utilized for group transfer polymerization (hereinafter referred to as GTP), and the GTP polymerization process is carried out by the American Chemical Society (Polymer Preprint, Am. Chem. Soc). ., 27 (1), 161 (1986)) is a recently known polymerization method, which is simply described as a "growth polymer that continues to grow while the unit has a reactive ketene silyl acetal group. It is added repeatedly to a growing polymer chain end.

This is called GTP because the curtain silyl acetal group can continue polymerization by adding new curtain silyl acetal functional groups to newly added units. In addition, in the polymerization of α, β-unsaturated esters, amides, and nitriles, as described on page 165 of the magazine, a polymerization method for GTP is introduced in the presence of a catalyst such as a polymerization initiator of curtainyrylacetals and some Lewis acids or anionic compounds. Doing. For example, the polymerization process by GTP of methyl methacrylate (MMA) unit is shown in Equation (1), and the initiator used is the curtain silyl acetal of β-methyl group, and the catalyst is called soluble bifluoride. GTP polymerization quickly produces a "living" polymer at room temperature and exhibits a new structure.

As the monomer used in the GTP, methacrylic monomers are preferred as described below. However, active hydrogen compounds interfere with the GTP process, and if there are more active hydrogen compounds than the initiator concentration, the growth of the polymerization chain is stopped.

Therefore, active hydrogen compounds such as methacrylic acid or hydroxyethyl methacrylate cannot be directly polymerized. However, the use of masking groups, which can be removed after the desired polymer is produced, can be circumvented. For example, the hydroxy group in question can be derived by using 2- (trimethylsilyloxy) ethylmethacrylate as a unit.

Acrylic units other than methacrylates can also produce copolymers, but the polymerized chains do not remain as "live" chains for a long time. This is because acrylates polymerize at a faster rate than methacrylates, and in the polymerization of units containing these two units at the same time, when the initiation reaction is initiated, only acrylates are polymerized as shown in Equation (2). Non-crosslinked polymers containing methacrylate groups. This is one example where the structure of the polymer can be controlled by adopting GTP.

In GTP, the polymerization conditions of monomers should be free of active hydrogen compounds, all chemicals and solvents should be pure as well as anhydrous and polymerization should be carried out in a dry state.

But oxygen is not disturbed. Typical solvents used in GTP are toluene, tetrahydrofuran (THF), 1,2-dimethoxyethane, acetonitrile, N, N-dimethylformamide (DMF), or the like for nucleophilic catalysts or Lewis acid catalysts. Toluene, 1,2-dichloroethane, dichloromethane and the like should be used.

The reaction temperature is preferably from -100 ° C to 150 ° C, but preferably 0-50 ° C. However, in order to polymerize acrylates, 0 degreeC or less is good. In general, since the polymerization is very fast, the reaction rate can be controlled according to the amount of the monomer added during the polymerization.

Attention is drawn to the induction period of some polymerization initiators and catalysts, for example trimethylsilylcyanide. Polymerization initiators known to date are introduced as 1-alkoxy-1- (trimethylsiloxy) -2-methyl-1-alkenes, ie compounds of formula (I), as the most suitable initiator for GTP. The more alkyl groups in the silicone, the lower the polymerization rate, and the -OR group is placed at one end of each polymerization chain to maintain functionality. As shown in Formula (3), α-silyl esters can be used as polymerization initiators of GTP since they can be replaced with ketene acetal.

In addition, some silic derivatives added to methacrylate, such as trimethylsilyl cyanide or trimethylsilylmethylsulphide, also generate curtain acetal, and thus act as a polymerization initiator. When trimethylsilyl cyanide is an ammonium cyanide ^upon-can be prepared from the silicon and trimethylchlorosilane _{((CH 3) 3 -Si-} Cl) (R 4 N + CN).

In addition, phosphorus-containing curtainylyl acetal can be used to prepare a polymer in which phosphorus is located at the end of the polymer as in Formula (5). Phosphorus-containing polymerization initiators are described in Synthesis, 1982, 497; 1982, 915. Its manufacturing method is introduced.

GTP requires a catalyst in addition to the initiator, and includes a nucleophilic catalyst such as soluble pullulide, bipululide, azide and cyanide. However, not only can it be easily prepared but the effective catalyst is tris (dimethylamino) sulfonium (TAS) bipululide, which is crystalline and soluble in organic solvents.

In addition, electrophilic catalysts such as zinc halides, alkylaluminum chlorides, and alkylaluminum oxides exhibit catalytic effects as in the magazine (J. Am. Chem. Soc., 05, 5706, 1983). However, nucleophilic catalysts are more advantageous in the GTP process than electrophilic catalysts because the nucleophilic catalysts require 0.1% based on the initiator, whereas the electrophilic catalysts require 10% based on the monomer. to be.

The molecular weight of the polymer produced by the GTP method is determined by the ratio of initiator to monomer as shown in formula (6). therefore

DP = monomer / initiator equation (6)

The molecular weight can be precisely adjusted in the range of 1,000-2,000. However, it is difficult to obtain a high molecular weight polymer. Because it is too small for the high molecular weight initiator, it will remain at the impurity level. On the other hand, if all are very pure units, solvents, catalysts and initiators, polymers can also be prepared at molecular weights of 100,000-200,000.

If the rate of initiator is equal to or greater than the propagation rate of the chain, all polymer chains will grow simultaneously and the polymer will have a narrow molecular weight distribution. In other words, the polydispersity approaches 1 as in Eq. (7).

식(7)

Formula (7)

In a conventional conventional manner, polymerization of homologous series such as methacrylate or acrylate yields a disordered randome copolymer. However, polymerization of acryl-based units such as acrylonitrile, methacrylonitrile, acrylate, and methacrylate by the GTP polymerization method can prevent the generation of randome type copolymers (Macromolecules, 17, 1417, 1984).

On the other hand, if all of the same series of polymers such as methacrylates are polymerized by the GTP method, a block-type polymer can be easily produced. When all the added units are used up, a new unit can be added. For example, when preparing an AB block polymer of methacrylate and acrylate, a block polymer may be prepared by adding a weakly reactive methacrylate first and then adding an acrylate unit to polymerize. This order of addition is because, as in formula (8), the end group of the dialkylketensilyl acetal of methacrylate is more active than the end group of the monoalkylketene of the "live" acrylate unit. Therefore, after the polymerization of methacrylate is completed, addition of acrylate units causes the chains of all polymers to grow simultaneously. Conversely, the reverse order causes polymers of high molecular weight to polymerize due to their high reactivity.

The addition of an active hydrogen compound, such as an alcohol such as water or medanol, to the "living" polymer produced as an intermediate, as described in US Pat. No. 4,508,880, yields the final product "non-living" as shown in Equation (9). ) Is converted to a polymer.

The above descriptions describe a GTP polymerization process in which a group of transferable groups is polymerized by polymerizing α, β-unsaturated hydrocarbons. In contrast to general polymerization, polymers with narrow molecular weight distribution can be obtained in the molecular weight distribution, so that they can exhibit certain physical properties.In the case of copolymerization, "living" intermediates can be prepared. After manufacture, since a more active unit can be added and superposed | polymerized later, manufacture of a random type copolymer can be prevented. In addition, "living" intermediates can remain "live" for a period of time if they are likely to be deactivated from active hydrogen compounds, allowing them to be used again at desired times.

Known reaction initiators for use in GTP are, as in U.S. Pat.Nos. 4,417,034 and 4,508,880, mainly of curtainysilyl acetals containing double bonds in alpha and beta. Therefore, as described above, the GTP method can polymerize or copolymerize units such as acrylates, methacrylates and acrylonitrile. However, in order to polymerize the triblock type copolymer of ABC, the A component is formed into a living polymer with a desired molecular weight, and then the B component is "living" and the "living" A polymer is polymerized by the addition of the "living" AB block. It was a disadvantage that the reaction step was complicated because it was made of a polymer and finally the C component was reacted with the AB block polymer to prepare a triblock copolymer of ABC.

The present inventors have been studied to improve these disadvantages, and as a result, the inventors have developed superior polymers than expected. TASHF ₂ ), tris (dimethylamino) sulfonium difluoro trimethylsiliconate (TASF), potassium bifluorolide (KHF ₂ ) and the presence of a solvent such as tetrahydrofuran, acetonitrile and the like, polymerized with α, β-unsaturated units Homopolymer or triblock type copolymer can be prepared. In particular, the present invention has a number of advantages over known methods for preparing triblock copolymers. For example, since there are groups on both sides, two monomers are produced at the same time as "living" polymers, and finally the other monomers are added. As a result, the triblock copolymer can be prepared, and thus the polymerization process is simple, and the molecular weight distribution can be kept constant.

Examples of the polymer used in the present invention include methacrylate, methyl methacrylate, butyl methacrylate, allyl methacrylate, acrylonitrile, and the like, and triblock copolymers include butyl methacrylate, methyl methacrylate, and butyl methacrylate. Acrylate, methacrylate and methyl methacrylate and methacrylate, allyl methacrylate and methyl methacrylate and allyl methacrylate, acrylonitrile and methyl methacrylate and acrylonitrile, methyl methacrylate and butyl Methacrylate and methyl methacrylate, methyl methacrylate and allyl methacrylate and methyl methacrylate.

And the bissiloxane polymerization initiator represented by the general formula (I) used in the present invention are three kinds as follows, [1,6-dimethoxy-2,5-dimethyl-1,5-hexadiene-1, 6-diylbis (oxy)] bis (trimethylsilane) (hereinafter referred to as A), [1,5-dimethoxy-2,4-dimethyl-1,4-pentadiene-1,5-diylbis (oxy) Bis [trimethylsilane (denoted B below), [1,4-dimethoxy-2,3-dimethyl-1,3-butadiene-1,4-diylbis (oxy)] bis (trimethylsilane) (hereinafter C) ).

The following examples will illustrate the invention in more detail but do not limit the scope of the invention.

Example 1

Polymerization of Polymethylmethacrylate (PMMA)

0.35 mmol of polymerization initiator A was added to 4 ml THF, followed by addition of 0.2 mmol of TASHF ₂ and stirring in an argon atmosphere for about 20 minutes while 15 mmol of methyl methacrylate (MMA) was sealed with a syringe and added slowly. After reacting for about 30 minutes, 3 ml methanol was added to stop the reaction, and the solvent was recovered. PMMA was quantitatively prepared.

Table 1 shows experimental data on the polymerization of butyl methacrylate (BMA), allyl methacrylate (AMA), methacrylate (MA) and acrylonitrile (AN) units under the same conditions as the polymerization.

[Table 1] Polymerization by Unit

Example 2

Preparation of Triblock Copolymer (PBMA-PMMA-PBMA)

0.33mm0l of polymerization initiator B and 0.05mmol of TASHF ₂ were added to 4ml of THF, and stirred for 20 minutes in argon atmosphere, 3.7mmol of MMA was added slowly and reacted for 30 minutes to make an MMA block polymer, followed by 7.6mmol of BMA Is injected into a syringe. After further proceeding for 1 hour, 3 ml of methanol was added to stop the reaction, and the solvent was recovered. Thus, a triblock copolymer composed of PBMA-PMMA-PBMA was prepared.

Table 2 shows the preparation conditions of the triblock copolymers carried out under the same conditions as the polymerization.

TABLE 2 Polymerization of Triblock Copolymer

Claims (5)

A method of polymerizing a homopolymer or triblock copolymer in the presence of a bissiloxane polymerization initiator of formula (I), a catalyst and a solvent.

In general formula (I), R represents a methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, 2-methylbutyl, or 3-methyl butyl group. R 'is the same as R, and R and R' may be the same or different. n is an integer from 0 to 2. The method according to claim 1, wherein the homopolymer is selected from methacrylate, methyl methacrylate, butyl methacrylate, allyl methacrylate or acrylonitrile. The butyl methacrylate, methyl methacrylate and butyl methacrylate, methacrylate and methyl methacrylate and methacrylate, allyl methacrylate and methyl methacrylate according to claim 1, And allyl methacrylate, acrylonitrile and methyl methacrylate and acrylonitrile, methyl methacrylate and butyl methacrylate and methyl methacrylate, methyl methacrylate and allyl methacrylate and methyl methacrylate. Polymerization method of the copolymer characterized in that it is selected. The method according to claim 1, wherein the catalyst is selected from tris (dimethylamino) sulfonium bipoolide, tris (dimethylamino) sulfonium difluurotrimethylsiliconate or potassium bifluorolide. The method of claim 1, wherein the solvent is selected from tetrahydrofuran or acetonitrile.