JPH0428422B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the use of polymeric polyamides having anion exchange groups.
Polymer polyB having A ⁺ and phenolic hydroxyl groups
The present invention relates to a novel ion exchanger formed by block copolymerization, which comprises all or a part of the constituent components. Block copolymers that form a unique microphase-separated structure are known to exhibit novel properties due to their microscopic heterogeneous structure, and various uses have been found for them. For example, block copolymers consisting of long polyisoprene or polybutadiene chains and short polystyrene chains are used as thermoplastic rubbers.
Block copolymers consisting of long polystyrene chains and short polyisoprene or polybutadiene chains are known as impact-resistant materials, and block copolymers consisting of polyurethane and polyether and hydrophilic poly(2-hydroxyethyl methacrylate) are known as impact-resistant materials.
A block copolymer consisting of polystyrene and hydrophobic polystyrene is expected to be an anticoagulant material. It is also known that block copolymers containing a polymer having perfluoroalkyl groups as one component are effective for surface modification of plastics and the like. Recently, polymers that can be introduced with cation exchange groups (e.g. polystyrene and polymethyl methacrylate)
and polymers that can introduce anion exchange groups (e.g.
An amphoteric ion exchanger is produced from a multi-component block copolymer consisting of poly(2-vinylpyridine) or poly(4-vinylbenzyldimethylamine)) and a polymer without ion exchange groups (e.g. polyisoprene or polybutadiene). It has been reported that it can be obtained. (Publication of Patent Publication No. 56-76408) These amphoteric ion exchangers have a sulfone group or a carboxyl group as a cation exchange group, and a sulfone group or a carboxyl group as an anion exchange group.
It has an ammonium base and functions as an amphoteric ion exchanger in a fairly wide pH range from acidic to alkaline, and is expected to be used as a membrane to separate low-molecular-weight organic substances and inorganic salts. After extensive research, the present inventors have discovered a novel block copolymer comprising a polymer poly A ⁺ having an anion exchange group and a polymer poly B having a phenolic hydroxyl group as part or all of its constituent components. I came up with the idea and succeeded in synthesizing it. In the molded products of these block copolymers, the different component blocks do not mix with each other and exist as microphase separated, and these molded products function as anion exchangers under near-neutral or acidic conditions, and under alkaline conditions. It was found that under certain conditions, it acts as an amphoteric ion exchanger. There is no doubt that these facts promise to provide ion exchangers as new functional materials. The present invention will be explained in more detail below. The ion exchanger according to the present invention is obtained from a block copolymer having a polymer poly A ⁺ having an anion exchange group and a polymer poly B having a phenolic hydroxyl group as part or the whole of its constituent components. In the block copolymer used here, the above
When poly A ⁺ and poly B are part of the constituent components, the remaining part is a polymer polyC that does not have a polar group.
Consisting of These block copolymers are made of, for example, polyA, a polymer capable of introducing anion exchange groups.
A polymer in which the hydroxyl group of poly B is protected with an appropriate protecting group.
polyB and, if necessary, polymers without polar groups
A block copolymer composed of polyC is subjected to a protective group elimination reaction and an anion exchange group introduction reaction before, after, or simultaneously with molding, and if necessary, a crosslinking reaction is performed. . The ion exchanger of the present invention has a phase-separated structure consisting of microdomains having anion exchange groups, microdomains having phenolic hydroxyl groups, or both microdomains and microdomains having no polar group. In block copolymers made of nonpolar polymers such as polyisoprene and polystyrene, different component blocks do not mix with each other in a fixed state, but phase separate into microdomains in the form of spheres, columns, or lamellas depending on the composition. It is known to do. In this case, the diameter of a spherical domain, the diameter of a columnar domain, the center distance between these domains, or the width of a lamellar domain is limited by the fact that component blocks are entangled with each other, so the extent of one block constituting these domains is limited. (usually tens to hundreds of angstroms). The present inventors have found a method to finally arrive at the ion exchanger of the present invention while utilizing such a microphase separation phenomenon. In the block copolymer used in the present invention, the component block having a phenolic hydroxyl group has the following engagement unit: (However, R ₄ is hydrogen or methyl group, R ₅ to
One of R ₉ is a hydroxyl group, and the others are hydrogen atoms or methyl groups. ) is a polymer with The hydroxyl group of such a polymer has a pKa (pKa=-logKa, Ka is the dissociation constant) of 10.
It hardly dissociates under acidic or neutral conditions, and only dissociates under alkaline conditions. Therefore, the ion exchanger of the present invention has a multiphase structure consisting of microdomains with anion exchange groups and microdomains with undissociated phenolic hydroxyl groups under acidic and near-neutral conditions, and under alkaline conditions. are microdomains with anion exchange groups and dissociated phenolic hydroxyl groups (i.e.
It has a multiphase structure consisting of microdomains with cation exchange groups). Furthermore, when the block copolymer used in the present invention contains a component block polyC that does not have a polar group, it has a multiphase structure including microdomains that do not have a polar group under any PH conditions. The anion exchange group of the component block poly A ⁺ of the block copolymer used in the present invention may be an ammonium group, a sulfonium group, a phosphonium group, etc. Among these, the ammonium group is a monomer selected from monomer group A below. It can be obtained by quaternizing the polymer polyA consisting of Monomer group A: 2-vinylpyridine, 4-vinylpyrimidine,
Vinylpyridines such as 2-methyl-5-vinylpyridine, vinylpyrimidines, vinylquinolines, vinylcarbazoles, vinylimidazoles, o, m, p-vinylphenylalkylenedialkylamines represented by dialkylaminoalkyl acrylates represented by _{Dialkyl acrylamides represented} by
an alkyl group, n is an integer from 1 to 3, and m is 2 or 3. ) The polymer poly B having a phenolic hydroxyl group can be obtained by polymerizing a monomer represented by the following chemical formula having a phenolic hydroxyl group protected with an appropriate protecting group, and then removing the protecting group. Here, R ₄ is a hydrogen atom or a methyl group, and any one of R ₅ to R ₉ is -O-CH ₃ (2) -O-CH ₂ R ₁₀ (3) (However, R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆
represents an alkyl group having 1 to 12 carbon atoms. ) etc., and the others are hydrogen atoms or methyl groups. The monomer species constituting the polymer polyC having no remaining polar groups may be selected from the following monomer group C, for example. Monomer group C: monomers having an aromatic ring such as styrene, α-methylstyrene, vinyltoluene, butadiene,
Diene-based monomers such as isoprene, pentadiene, cyclohexadiene, diphenylbutadiene, etc. Using such polymer polyC as a component block, in addition to polymer poly A ⁺ having anion exchange groups and polymer poly B having phenolic hydroxyl groups, By forming a copolymer, it is possible to increase the mechanical strength of the material and stabilize the microphase-separated structure. In particular, polymers made of diene monomers can be easily crosslinked, so their use can improve the solvent resistance of the material. A preferred method for obtaining the ion exchanger of the present invention is to use a living anionic polymerization method using a monomer selected from monomer group A, a monomer represented by chemical formula (1), or both, and a monomer selected from monomer group C. An original block copolymer consisting of a polymer polyA into which an anion exchange group can be introduced, a polymer polyB into which a phenolic hydroxyl group can be introduced, or both of these polymers, and a polymer polyC without a polar group is molded. After, before, or at the same time as molding, anion exchange groups are introduced (quaternization of nitrogen atoms) and hydrolysis is carried out. When obtaining the original block copolymer by a living anionic polymerization method, among the monomers represented by the chemical formula (1), monomers having a protecting group represented by the chemical formula (4), (5) or (6) are preferable, and more preferably. is a monomer having a protecting group represented by chemical formula (4) or (5), most preferably a monomer having chemical formula (5). Initiators for living anionic polymerization include known butyl thirium (n, sec, tert, etc.), 2-methylbutyl lithium, sodium naphthalene, sodium anthracene, sodium α-methylstyrene tetramer, sodium biphenyl, cumyl potash, butyl cesium. (n, sec,
tert etc.) etc. are used. As the polymerization solvent, aromatic hydrocarbons, cyclic ethers, aliphatic hydrocarbons (generally benzene, toluene, tetrahydrofuran, n-hexane, cyclohexane, etc. are used) are used, and vacuum or nitrogen gas, argon gas, etc. Polymerization is carried out under an active gas atmosphere. The original block copolymer used in the present invention has the above polymers polyA, polyB, and polyC, for example,
(polyA−polyB) _x , (polyA−polyB)− _x polyA,
polyB(−polyA−polyB) _x , (polyA−polyB−
polyC) _x , (polyB−polyA−polyC) _x , (polyA−
polyC−polyB) _x , (polyA−polyC−polyB−
polyC) _x , (polyC−polyA−polyC−polyB) _x ,
polyC−polyA−polyB−polyC, polyC−polyA
−polyC−polyB−polyC, polyA−polyC−
polyB−polyC−polyA, polyB−polyC−polyA
−polyC−polyB, polyA−polyB−polyC−
polyB−polyA, polyB−polyA−polyC−polyA
−polyB, polyC−polyA−polyB−polyA−
polyC, polyC−polyB−polyA−polyB−polyC
(However, x is an integer of 1 or more) connected in an array may be sufficient. Among these, polyA and polyB are separated from each other by polyC and combined,
polyA−polyC−polyB, (polyA−polyC−
polyB−polyC) _x , (polyC−polyA−polyC−
polyB) _x , polyC−polyA−polyC−polyB−
polyC, polyA−polyC−polyB−polyC−polyA,
In polyB-polyC-polyA-polyC-polyB, if the polyC content is appropriate (usually about 30% or more of the block copolymer by weight), microphase separation occurs in the final ion exchanger. A domain having an anion exchange group and a domain having a phenolic hydroxyl group are separated from each other by a domain having no polar group. Such an ion exchanger has a stable microphase-separated structure in a wide pH range from acidity to alkalinity, so it can be said to be preferable for use as a functional material. The molecular weights of the component polymers polyA, polyB, and polyC constituting the above original block copolymer are 10 ³ to 10 ⁶
g/mol is desirable. More preferably, it is 10 ⁴ to 5×10 ⁵ g/mol. As is generally well known, in block copolymers, as the molecular weight decreases, the volume fraction of the compatible interface area generated between two adjacent domains formed by microphase separation increases. For this reason, in samples with low molecular weight, polyion complexes are largely formed in the alkaline region, and the characteristics of the ion exchanger of the present invention are diminished. According to experimental facts published so far on various block copolymers, it is thought that a clear phase-separated structure is hardly formed when the molecular weight of each component block is 10 ³ g/mol or less. On the other hand, if the molecular weight of the sample is too large, molding becomes difficult due to its high viscosity in the melt or solution state. In the original block copolymer used in the present invention, the weight fraction of the region having an anion exchange group and the region having a phenolic hydroxyl group in the ion exchanger finally obtained is 5% or more of the ion exchanger. It is necessary to have the molecular weight and content ratio of polyA and polyB. This is because if their weight fraction is less than 5%, the characteristics of the ion exchanger will be significantly impaired. The nitrogen molecules of the polymer polyA used in the present invention into which an anion exchange group can be introduced can be quaternized using an alkyl halogen compound or an alkylene dihalide. As the alkyl halogen compound, XC _l H _2l+1 ,
As alkylene dihalides, X(-C ₂ H ₄ )- _l
X (However, X is a bromine or iodine atom)
There are compounds where l is 1 to 12. Further, this quaternization can be carried out using a chloromethylated aromatic compound such as chloromethylbenzene or an acid halide such as benzenesulfonyl chloride or acetyl chloride. The quaternization reaction can be carried out in vapor or solution of these compounds. On the other hand, these polyA
The nitrogen atom can also be converted into a tertiary ammonium salt using hydrochloric acid or the like. In order to obtain a polymer having a phenolic hydroxyl group from a polymer consisting of a monomer represented by the chemical formula (1), a protecting group may be removed by a known method. (Literature; TW Greene, “Protective Groups
in Crganic Synthesis,” John Wiley & Sons,
New York, 1981) For example, in the case of the protecting group represented by chemical formula (5),
The elimination reaction can be easily carried out by dropping hydrochloric acid, hydrobromic acid, or hydroiodic acid onto a sample under heating in a solvent such as dioxane, acetone, methyl ethyl ketone, or acetonitrile. The reaction can also be carried out at relatively low temperatures using anhydrous 1,1,1-trifluoroacetic acid or a mixture of acetic acid and hydrobromic acid or a solution of trimethylsilyl iodide in carbon tetrachloride or chloroform. Ion exchangers with phenolic hydroxyl groups as described above can be used as highly selective separation membranes, biomedical materials,
It is expected to have a wide range of uses as a gel for liquid chromatography, a surface modification material, etc. Hereinafter, the present invention will be explained with reference to Examples. Example 1 After dehydration with calcium hydride, 2.1 x 10 ^-4 mol of n-butyllithium, an initiator for anionic polymerization, was added to 600 ml of tetrahydrofuran purified using n-butyllithium, and p- tert
12g of butoxystyrene was added and left for about 20 hours. (First stage) After collecting a portion of the polymer, 11.8 g of isoprene was subsequently added and left to stand for about 20 hours. (Second stage) After collecting a part of the polymer, 11.5g of 4-vinylbenzyldimethylamine (4-VBDMA)
was added and left for about 20 hours. (Third step) Among the three types of monomers used here, p-
Tert-butoxystyrene was purified in advance using sodium benzophenone, then treated with a mixture of triphenylmethyllithium and lithium bromide, and purified by vacuum distillation. 4-VBDMA was dehydrated with calcium hydride, distilled under reduced pressure, and then treated with a mixture of triphenylmethyllithium and lithium bromatode, followed by vacuum distillation. Isoprene was dried with calcium hydride and sodium and then distilled. The number average molecular weight of the polymer obtained at each stage of polymerization was determined by membrane osmotic pressure method.
5.6×10 ⁴ g/mol in the first step, 1.10× in the second step
10 ⁵ g/mol, and 1.66×10 ⁵ g/mol in the third stage, which agreed well with the value calculated from the initiator and monomer weights charged. In addition, the polymerization yield is approximately 100
%, and the weight ratios of carbon, hydrogen, and nitrogen contained in the final polymer were 83.8% and 83.8%, respectively.
They were 10.1% and 2.8%, which agreed well with the calculated values. For this final polymer, 3%
When GPC measurement was performed using tetrahydrofuran containing N,N-dimethylbenzylamine as an eluent, a single peak was observed, indicating that the molecular weight distribution of this sample was quite narrow. (FIG. 1) Furthermore, FIG. 2 shows the infrared absorption spectrum of the final polymer. From the above results, in this example, poly(4
-VBDMA), polyisoprene and poly(p-tert)
butoxystyrene) polyA−polyC−
It is certain that a polyB type tertiary block copolymer was obtained. Thickness made from benzene solution of final polymer
A 60 μm film was stained with quaternized osmium,
When observed with a transmission electron microscope, the polyisoprene domain (I), poly(p-tert-butoxystyrene) domain (B), and poly(4-VBDMA) domain (A) were found to be of -I-B-I-A-. A lamellar microphase-separated structure with regularly arranged repeating units was confirmed. The thickness of one layer was approximately 150 angstroms. The anion exchange group and phenolic hydroxyl group were introduced as follows. 0.30 g of a 60 μm thick film prepared in the same manner was treated with 1.3 diiodopropane vapor at room temperature for 40 hours to quaternize and crosslink the poly(4-VBDMA) portion. This film was immersed in acetone at 50°C, a small amount of concentrated hydrobromic acid was added to initiate the removal of the tert-butyl group from poly(p-tert-butoxystyrene), and an appropriate amount of dilute aqueous hydrogen bromide solution was added. In addition, the mixture was left to stand for about 10 hours to completely eliminate the tert-butyl group. Complete removal of the tert-butyl group was confirmed by ^H1 -NMR. That is, the peak attributable to the t-butyl group observed before the elimination reaction is
It completely disappeared and a new large peak that was considered to be a phenolic hydroxyl group appeared. The film thus obtained was coated with 1N KCl.
The membrane was immersed in an aqueous solution for one day and one night, and after washing with water, it was immersed in a 1N NaNO ₃ aqueous solution for two days, and the amount of chlorine ions released was determined, and it was found that 5.6 moles of anion exchange groups were present in the membrane. Furthermore, this film was immersed in 1N hydrochloric acid overnight, and after washing with water, it was diluted with 1N NaCl.
Although it was immersed in an aqueous solution for 2 days, no release of hydrogen ions was observed. On the other hand, when a film treated with 1N hydrochloric acid and washed with water was immersed for two days in a mixture of common salt and sodium hydroxide (15ml of 0.1N sodium hydroxide aqueous solution added to 100ml of 1mol/saline solution), 5.3mol It was found that hydrogen ions were liberated. Thus, the poly(p-hydroxystyrene) moiety dissociates only under alkaline conditions. Therefore, the ion exchanger obtained in this example is referred to as an amphoteric ion exchanger only in the alkaline region. Example 2 Tetrahydrofuran purified in the same manner as Example 1
After adding 1.7 x 10 ^-4 mol of n-butyl lithium to 700 ml, 3.8 g of butadiene, 9.0 g of p-tert-butoxystyrene, 3.7 g of isoprene, 8.9 4-VBDMA
g and 3.7 g of butadiene were added in five stages to carry out block copolymerization. Polymerization time is approximately 20 per stage
It was time. The purification method of p-tert-butoxystyrene, isoprene and 4-VBDMA was the same as in Example 1.
Butadiene was purified in the same manner as isoprene. The number average molecular weight of the polymer obtained at each stage of polymerization, determined by membrane osmotic pressure method, almost matched the value calculated from the number of moles of initiator and the total weight of monomers added up to each stage of polymerization. . In addition, the polymerization yield was almost 100%, and the elemental analysis results of the final polymer were in good agreement with the calculated values, and GPC
The measurement results also showed that the molecular weight distribution was narrow. From the above results, in this example, poly(4
-VBDMA), polyisoprene, polybutadiene, and poly(p-tert-butoxystyrene)
It is certain that a polyC-polyA-polyC-polyB-polyC type five-component block copolymer (polyC at both ends is polybutadiene and polyC at the center is polyisoprene) was obtained. Thickness prepared from dioxane solution of final polymer
A 60 μm film was stained with osmium tetroxide,
When observed with a transmission electron microscope, polydiem domain (D) and poly(p-tert-butoxystyrene)
domain (B) and poly(4-VBDMA) domain (A)
A microphase-separated structure in which repeating units of -D-B-D-A- were regularly arranged in a lamellar shape was confirmed. 0.30 g of a film with a thickness of 60 μm prepared in the same manner was subjected to quaternization of the amine portion in the same manner as in Example 1.
When the -butyl group was eliminated, a membrane having 5.2×10 ^-4 moles of anion exchange groups and 4.9×10 ^-4 moles of phenolic hydroxyl groups was obtained. Example 3 2.0×10 ^-4 n-butyllithium was added to 600 ml of tetrahydrofuran purified in the same manner as in Example 1.
After adding moles, 11 g of 2-methyl-4-tert-butoxystyrene was added and left to stand for about 20 hours. (1st
Step) After collecting a portion of the polymer, 10.5 g of 4-vinylpyridine was added and left for about 20 hours.
(Second Step) The two types of monomers used here were purified in advance in the same manner as p-tert-butoxystyrene described in Example 1. When the number average molecular weight of the polymer obtained at each stage of polymerization was measured, it was found that in the first stage it was 5.6 ×
10 ⁴ g/mol, and 1.06×10 ⁵ g/mol in the second stage, which agreed well with the value calculated from the weight of the initiator and monomer charged. The polymerization yield was approximately 100%, and the GPC elution curve measured in the same manner as in Example 1 showed a single narrow peak. These facts are explained in this example by poly(4-
vinylpyridine) and poly(2-methyl-4-tert)
This shows that a polyA-polyB type binary block copolymer consisting of (butoxystyrene) was obtained. The results of elemental analysis and infrared absorption spectrum were also consistent with such a block copolymer. A 60 μm thick film made from a dioxane solution of this block copolymer was stained with osmium tetroxide and observed with a transmission electron microscope.
Poly(2-methyl-4-tert-butoxystyrene)
A microphase separation structure in which domains (M) and poly(4-vinylpyridine) domains (P) were arranged alternately in a lamellar manner was confirmed. The thickness of each of these layers was 150-200 Angstroms. 0.30 g of the obtained block copolymer was dissolved in 100 ml of benzene, 2 ml of methyl iodide was added, and the mixture was left under stirring for 2 hours. After drying, the recovered polymer was dissolved in 10 ml of acetone at 50°C, a small amount of concentrated hydrobromic acid was added, and after stirring for 5 minutes, 0.5 ml of dilute hydrobromic acid was added and the mixture was left stirring for 5 hours. A 40 μm thick film cast from this solution at room temperature was irradiated with ultraviolet rays for several hours to make it insoluble in water, and then anion exchange groups and phenolic hydroxyl groups were determined in the same manner as in Example 1. As a result, each
They were 1.05×10 ^-3 mol and 2.42×10 ^-4 mol.

[Brief explanation of drawings]

Figure 1 shows the GPC of the final polymer obtained in Example 1 detected with a differential refractometer (RI-8 manufactured by Toyo Soda).
This is an elution curve. Column GMH6 manufactured by Toyo Soda Co., Ltd. (length 60 cm, inner diameter 7.5 mm), 3% N, N as eluent
- Measurements were made using tetrahydrofuran containing dimethylbenzylamine at a flow rate of 1 ml/min. Figure 2 is an infrared absorption spectrum of the same polymer.

Claims (1)

[Scope of Claims] 1. A polymer having an anion exchange group and a polymer having a phenolic hydroxyl group are used as the whole component or a part thereof together with a polymer having no polar group, and the anion exchange group is The content of each of the polymer with phenolic hydroxyl group and the polymer with phenolic hydroxyl group is 5
An ion exchanger consisting of a block copolymer that is greater than or equal to a weight percent. 2. The ion exchanger according to claim 1, wherein the anion exchange group is an ammonium base, a phosphonium base, or a sulfonium base. 3. The ion exchange according to claim 1 or 2, wherein the polymer having an anion exchange group is a polymer made of a monomer selected from monomer group A below, into which an anion exchange group is introduced. body. Monomer group A: vinylpyridines, vinylpyrimidines, vinylquinolines, vinylcarbazoles, vinylimidazoles, o, m, p-vinylphenylalkylenedialkylamines represented by dialkylaminoalkyl acrylates represented by Dialkyl acrylamides represented by (However, n = 1 to 3, m = 2 or 3, R ₁ and R ₂ are each an alkyl group having 1 to 12 carbon atoms, R ₃
is hydrogen or an alkyl group having 1 to 12 carbon atoms. ) 4 The polymer having a phenolic hydroxyl group has the following formula: (However, R ₄ is hydrogen or methyl group, R ₅ to
One of R ₉ is a hydroxyl group, and the others are hydrogen or methyl groups. ) The ion exchanger according to any one of claims 1 to 3, having a bonding unit represented by: 5 Claim 1 in which the block copolymer contains 30% or more by weight of a polymer having no polar groups
The ion exchanger according to any one of items 1 to 4. 6. The ion exchanger according to any one of claims 1 to 5, wherein the polymer having no polar group comprises a diene monomer. 7. The ion exchanger according to any one of claims 1 to 5, wherein the polymer having no polar group comprises a monomer having an aromatic ring.