JPS5986612A - Polymer membrane - Google Patents

Abstract

PURPOSE:A polymer membrane excellent in oxygen permeability and mechanical properties and useful as a gas separation membrane, prepared from polystyrene having a tris(triorganosiloxy)siloxanyl group in the side chain. CONSTITUTION:The desired polymer membrane is obtained from polystyrene having a tris(triorganosiloxy)siloxyanyl group in the side chain, either having a repeating unit of formula I [wherein X is -NH- or -O-, A and B are each an organic group selected from the group consisting of -OR-, -OSiR3, -OSiR2- OSiR3, and -OSi(OSiR3)3, and R is a 1-5C alkyl or a phenyl] or having both the above repeating unit and a repeating unit of formula II (wherein Y is H, or CHO, Z is an organic group selected from those of formula III, wherein M is -NR2, R is a 1-5C alkyl or phenyl, R<1> is a 1-5C alkylene, or phenylene).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polymer membrane, and more specifically, a polymer membrane made of polystyrene having a tris(triorganosiloxy)siloxanyl group in a side chain and which can be suitably used as a gaseous bone membrane. Regarding.

In recent years, gas separation using organic polymer membranes, especially the oxygen enrichment of air, has been attracting attention, and attempts have already been made to treat patients with respiratory diseases, and to enrich the air for combustion furnaces with oxygen. Some of them have already been put into practical use.

Generally, the gas permeation rate is given by the following equation.

Here, P is the permeability coefficient (CI・Cm / CI・sec・c
mHg), Δp is the difference in gas partial pressure on both sides of the membrane, A is the membrane surface ljl (c+J), and e is the membrane thickness (cut). Therefore, in order for a membrane to have practical gas separation properties, it is important not only to have a large permeability coefficient P but also to be able to reduce the membrane thickness β. The bigger the better.

This membrane is the largest of the conventionally known polymer membranes, but as this membrane has low mechanical strength, it is necessary to have a thickness of 100μ or more, and therefore the permeability coefficient is Even if it is large, the permeation speed cannot be increased.

Further, the permeability coefficient ratio of oxygen to nitrogen is about 2 at most, and the selective separation of oxygen is poor. For this reason, US Pat. No. 3,189,662 proposes a gas separation membrane made of a polysiloxane/polycarbonate block copolymer. This membrane can be made as thin as 1μ or less, and the permeability coefficient can be controlled by the dimethylsiloxane content, but the oxygen permeability coefficient is 5X10-9cJ (ST
P ) ·cm/cut·sec·cml In the range of dimethylsiloxane content of 1 g or more, the permeability coefficient ratio of oxygen to nitrogen is about 2 to 2.7.

Even with polymer membranes that can be made thinner to increase the permeation rate, when the permeability coefficient is increased to the level of polydimethylsiloxane, the permeability coefficient ratio decreases, and the permeability coefficient ratio decreases to 3.
When increasing to ~4 times, the permeability coefficient is 10-9cl
(STP) ・cm/cra ・sec・cmHg
decreases to the order of .

As a result of intensive research to solve the above problems, the present inventors have found that by introducing tris(triorganosiloxy)siloxanyl groups into the side chains of polystyrene, it has excellent oxygen permeability and selectivity, and The present invention was achieved by discovering that it is also possible to make the film thinner.

The first polymer film according to the present invention has the general formula (1) (wherein, (os j+ < 3) Tris(+-liorganosiloxy) having a repeating unit represented by an organic group selected from the group consisting of 3, where R represents an alkyl group having 1 to 5 carbon atoms or a phenyl group. It is characterized by being made of polystyrene with siloquinanyl groups in its side chains.

Further, the second polymer film according to the present invention has the above general formula (1
) and the general formula ■ (Il) (where Y represents -H or -CH3, Z represents an organic group selected from the group consisting of, M represents -NR2, and R represents carbon Represents an alkyl group or phenyl group of numbers 1 to 5, R'
represents an alkylene group or phenylene group having 1 to 5 carbon atoms. ) is characterized in that it is made of substantially linear polystyrene having a tris(triorganosiloxy)siloxanyl group as a side chain.

The first polymer membrane according to the present invention made of polystyrene having a repeating unit represented by the general formula (I) is represented by the general formula ([) (where X, , A, B and R are the same as above) A styrene derivative monomer having a tris(+-liorganosiloxy)siloxanyl group in its side chain is subjected to ordinary vinyl polymerization using a polymerization initiator in an appropriate organic solvent to obtain a polymer. It can be obtained by forming a film using the method described below. In addition, when R is an alkyl group, a methyl group, an ethyl group, etc. can be mentioned as a preferable example, However, It is not necessary that all R's are the same.

The same applies to general formula (1).

The styrene derivative monomer represented by the general formula (III) is combined with a trialkoxysilane compound represented by the general formula () (where X and R are the same as above) in the presence of sulfuric acid, and a trialkoxysilane compound represented by the general formula (% formula %) () (However, R is the same as above) Tris(triorganosiloxy)acetoxysilane, or this and the following general formula % Formula % () () (However, R is the same as above) This can be carried out by reacting a mixture of triorganosilane or acetoxypentaroganodisiloxane.

The trialkoxysilane compound represented by the general formula (IV) is composed of a nuclear-substituted styrene represented by the general formula (■) (where, It can be obtained by reaction with γ-isocyanatopropyltrialkoxysilane represented by

Here, T-isocyanatopropyltrialkoxysilane is commercially available as a silane coupling agent.

The styrene derivative monomer having a tris(triorganosiloxy)siloxanyl group in the side chain represented by the general formula (II[) obtained as described above can be polymerized in bulk or in an appropriate organic solvent using a polymerization initiator. If vinyl polymerization is carried out by a conventional method such as solution polymerization using the above-mentioned general formula (1), a polymer having one repeating unit represented by the general formula (1) can be obtained.

The vinyl polymerization method is not particularly limited, and may be radical polymerization, cationic polymerization, or anionic polymerization. The polymerization initiator is appropriately selected depending on the respective polymerization method, and for example, in the case of radical polymerization, a peroxide such as benzoyl peroxide or an azo compound such as azobisisobutyronitrile is used. In some cases, non-catalytic thermal polymerization is also possible. Further, in the case of cationic polymerization, boron trifluoride diethyl etherate and the like are used, and in the case of anionic polymerization, n-butyllithium and the like are used. It goes without saying that other monomers may be used as copolymerization components in the above polymerization, if necessary.

When polymerizing the styrene derivative monomer represented by the above general formula (I[[) in an organic solvent, the solvent may be
A solvent that dissolves this monomer and is inert to it and also dissolves the produced polymer is used, and aromatic hydrocarbons such as benzene are particularly preferably used.

2 The amount of solvent used is not particularly limited, but if the monomer concentration is 1
It is appropriate to use it in an amount of about 100% by weight, preferably about 10 to 50% by weight.

The polymerization temperature is usually in the range of room temperature to 100°C, and the reaction time is usually in the range of 1 hour to 24 hours.

The polystyrene having a tris(triorganosiloxy)siloxanyl group in the side chain obtained as described above usually has a logarithmic viscosity of 0.1 to 1.0 (in benzene, 0.5
g/dβ (measured at 30°C), and has excellent film forming properties.

The first polymer film according to the present invention is produced by forming the polystyrene obtained as described above into a film as described below.

Next, the second polymer film according to the present invention has the general formula (I
) In addition to the repeating unit represented by formula (n), the copolymer is composed of a substantially linear copolymer containing an effective amount of the repeating unit represented by general formula (n).

In general formula (II), R is as described above, but R' represents an alkylene group having 1 to 5 carbon atoms or a 3-phenylene group, and a preferred specific example of the alkylene group is -CH2CH2-1-CH (CH3) CH2
- and so on.

Such a second polymer film is made of a styrene derivative having a tris(triorganosiloxy)siloxanyl group represented by the general formula (I[) in its side chain, and a styrene derivative represented by the general formula (I[)] (wherein Y and Z are It can be obtained by copolymerizing with an ethylenically unsaturated monomer represented by As mentioned above, the copolymerization method is not particularly limited as long as it is vinyl polymerization.

In the ethylenically unsaturated monomer represented by the general formula (X), Y is -H or -CH3-, and preferred specific examples of 2 include 4 and the like. Therefore, preferred ethylenically unsaturated monomers that can be used in the present invention include styrene, p-dimethylaminostyrene, ethyl meccrylate, 2-dimethylaminoethyl methacrylate, and 4-vinylpyridine.

The polymer film according to the present invention can be produced by various methods from the above polystyrene having a tris(triorganosiloxy)siloxanyl group in the side chain or a copolymer with a monomer represented by the above general formula (X). can. Normally,
The polymer obtained as described above is dissolved in an appropriate organic solvent to obtain a uniform film-forming solution, which is cast onto an appropriate support base material, and then the solvent is evaporated to form a homogeneous film. get.

A thin film can also be obtained by pouring the film-forming solution onto a liquid having a specific gravity 5 higher than that of the solution, developing it, and then evaporating the solvent. As the solvent for preparing the film-forming solution, aromatic hydrocarbons such as the above-mentioned benzene and toluene are preferred, but tetrahydrofuran is also used.

In order to increase the gas permeation rate, the thinner the film thickness, the better, and preferably 0.05 to 30μ. Therefore, the polymer concentration of the membrane forming solution is preferably 10% by weight or less.

As described above, in the membrane according to the present invention, polystyrene or its copolymer has tris(triorganosiloxy)siloxanyl groups in the side chains, and these triorganosiloxy groups form a field for oxygen permeation. It has extremely high oxygen permeability. Further, since the polymer main chain is formed of a rigid carbon-carbon skeleton, the film according to the present invention has excellent mechanical properties and can be made thin.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, in the following examples, the gas permeability coefficient P
was determined by the high vacuum method at a temperature of 25°C.

Example 1 Synthesis of (alN-(pentakis(trimethylsiloxy)siloxanylpropyl), N'-p-styrylurea) In the presence of a small amount of polymerization inhibitor, pt-butylcatechol, p-aminostyrene 83 In a solution of .3 g (0.70 mol) of benzene (750 g), with stirring, T
-162g of isocyanatopropyltriethoxysilane (
0.74 mol) was gradually added dropwise, and the mixture was reacted at room temperature for 3 hours. The progress of the reaction was monitored by gas chromatography.

Next, tris(trimethylsiloxy)acetoxysilane 2 was added while cooling the reaction mixture to below 10°C with ice water.
48 g (0.70 mol) and 185 g (1.4 mol) of trimethylacetoxysilane were added. While continuing to stir,
An ethanol solution of sulfuric acid (30% by weight, 50 g) was slowly added dropwise over a period of 1 hour, and the reaction mixture was returned to room temperature at 8:00 p.m.
It was allowed to react for a while.

After this, 200 g of distilled water was added to the reaction mixture and washed.
After removing the separated aqueous layer, it was washed with an aqueous sodium bicarbonate solution, washed again with distilled water, and then dried over magnesium sulfate.

The monomer solution thus obtained was heated to 60°C while reducing the pressure with an evaporator connected to an aspirator to remove the solvent, and then heated to 0.5 m with a vacuum pump.
The remaining volatiles were removed by heating to 80° C. under reduced pressure of ml (g).

(B1 Synthesis of Polymer N-(pentakis(trimethylsiloxy)siloxanylpropyl), which is the monomer obtained in fa) above].

10 g of N'-p-styrylurea and 40 g of benzene were charged into a glass ampoule with a cock, and then 3 g of a 10% by weight benzoyl peroxide solution in benzene was charged, and while cooling in a dry ice-methanol bath, The system was connected to a vacuum line for degassing, and a cycle of nitrogen substitution, melting, and cooling was repeated to remove oxygen in system 8. After this, the system was kept in vacuum and the ampoule was sealed.

The ampoule was left in a thermostat at 70°C and shaken.
Polymerization was carried out for 16 hours. The ampoule was opened and the reaction mixture was poured into a large amount of methanol to precipitate the polymer. After washing this polymer with methanol, it was filtered and vacuum-dried at a temperature of 60° C. for 8 hours to obtain 9.2 g of a polymer. The logarithmic viscosity of this polymer was 0.55.

The polymer obtained in the production of the Tel gas separation membrane was purified by the reprecipitation method in a benzene-methanol system, then made into a 5% by weight benzene solution, and 4μ
Foreign matter was removed using a filter paper to obtain a membrane forming solution. Distilled water heated to 40° C. was placed in a vat, and the film forming solution was gently poured onto the water surface using a syringe and spread to form a thin film. This thin film was scooped up with a porous polypropylene membrane (Duraguard manufactured by Polyplastics) and vacuum-dried at 60° C. for 8 hours. The thin film thus obtained has a thickness of 4 μm.
It was a homogeneous film.

9 The gas permeability coefficient measured by the high vacuum method is 6.5 x 10-9ca (STP) ・Cm for oxygen.
/cn-sec・mark Hg, 1.7X10 c for nitrogen
+11 (STP) ・mark/d・sec・(to) Hg.

Example 2 Using 5 g of the monomer obtained in Example 1 and 5 g of p-dimethylaminostyrene, the procedure was carried out in the same manner as in Example 1 until the logarithmic viscosity was 0.
．． 62 copolymers were obtained.

Using this copolymer, a homogeneous membrane was prepared in exactly the same manner as in Example 1, and the permeability coefficient was measured.
It is cIa·sec·cmHg, and the permeability coefficient ratio to nitrogen is 5, and if the permeability coefficient of oxygen is considered, it is understood that it is an extremely high performance membrane.

Example 3 Membranes were obtained in the same manner as in Example 1, except that X, A, B, R, Y, and Z in the general formula were variously changed. Permeability coefficient PX10cJ(STP)・c for these membranes
m/aa-sec.cmlg is shown in the table below.

0

Claims (2)

[Claims] (1) General formula (wherein, is a group, and R has 1 to 1 carbon atoms.
5 represents an alkyl group or a phenyl group. ) A polymer film comprising polystyrene having a tris(triorganosiloxy)siloxanyl group in a side chain having a repeating unit represented by: (2) General formula (where, X represents -NH- or -O-, A and B represent -OR・-05xR3・-08IR20SiR3 and
-O5L (O5iR3)3 is an organic group selected from the group consisting of
5 represents an alkyl group or a phenyl group. ), and a repeating unit represented by the general formula Y (where, Y represents -H or -CH3, Z represents an organic group selected from the group consisting of, M represents -N R2, and R
represents an alkyl group or phenyl group having 1 to 5 carbon atoms, and R
" represents an alkylene group or a phenylene group having 1 to 5 carbon atoms. ) A polymer film comprising substantially linear polystyrene having a 1-lith(triorganosiloxy)siloxanyl group in a side chain having a repeating unit represented by: