JPH0131907B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an antithrombotic gas permeable membrane. Graft copolymers are multiphase polymers that have a microscopic multiphase structure, whereas ordinary polymers have a single phase, and they have a wide variety of combinations of component polymers, the ability to develop higher-order structures, and unique properties. Depending on the mechanical properties of the material, we can expect the development of multiphase materials with new multifaceted functions. Graft copolymers, which are made by linking two different types of polymer chains (for example, hydrophilic and hydrophobic), undergo phase separation during the process of forming a film from a solution, resulting in a film with a non-uniform surface structure. Such a heterogeneous surface structure enables selective adsorption and activation of blood proteins,
It is thought to be involved in blood coagulation through the adhesion and deformation of platelets. Furthermore, depending on the properties and regularity of the higher-order structure of the component polymers, selective permeation of gases such as oxygen and carbon dioxide, accelerated permeation of water and alcohol, and selective permeation of solutes such as metal ions, sugars, and amino acids are possible. It is thought that transparency etc. can be realized. Against this background, the present inventors have conducted repeated research to obtain a heterogeneous polymer that is expected to have antithrombotic properties and selective permeability, and have developed a combination of a polydimethylsiloxane trunk and poly(α-amino acid) branches. The present invention was completed based on the discovery that a graft copolymer consisting of That is, the object of the present invention is to provide an antithrombotic material having excellent oxygen permeability, and the gist of the present invention is to provide an antithrombotic material having excellent oxygen permeability. The invention consists in an oxygen-permeable antithrombotic material whose main component is a graft copolymer obtained by graft copolymerizing amino acid N-carboxy anhydride. The present invention will be explained in detail below. (i) Polydimethylsiloxane (stem) and poly(α-
Synthesis of a graft copolymer consisting of polydimethylsiloxane (hereinafter referred to as PDMS) (amino acids) (branches)
A graft copolymer with poly(α-amino acid) as a trunk polymer and poly(α-amino acid) as a branch polymer is
Part of the methyl group of PDMS is replaced with 3-aminopropyl group, that is, amino side chain
α-amino acid NCA using PDMS as an initiator
(NCA stands for N-carboxy anhydride). amino side chain
PDMS Manufactured by Petrarch Systems, USA
There is a commercially available product, and this one is GPC
The number average molecular weight determined by the method is 25,000 (number average degree of polymerization 338), and the amino group content determined by acid-base titration is 7.2 per polymer chain. Therefore, the structure of amino side chain PDMS is as follows. Amino side chain PDMS with this structure is
It is thought to be synthesized by reacting PDMS and 3-aminopropylmethyldiethoxysilane in the presence of an alkali catalyst. Next, α-amino acid NCA was polymerized using amino side chain PDMS as an initiator to produce a graft copolymer with a microheterogeneous structure. Production Example 1 In this example, the above amino side chain PDMS was used as the initiator polymer, and α-amino acid NCA
as ε-carbobenzoxy-L-lysine NCA
[Hereafter abbreviated as LYS(Z)NCA] was used to carry out graft copolymerization. Amino side chain PDMS 1.0g and
Dissolve 2.0 g of Lys (Z) NCA in tetrahydrofuran, a polymerization solvent, and add both solutions together (Lys
(Z) NCA concentration is 0.3M) Shake carefully. Methylene chloride can also be used as a polymerization solvent. At this time, bubbles were immediately generated from the liquid surface, and it was observed that decarbonation gas was occurring.
This was left in a desiccator for 6 hours to polymerize. Thereafter, the solvent was distilled off and concentrated (if tetrahydrofuran was used, dimethylformamide was added and then concentrated), and the mixture was added to ether to produce a white precipitate. This precipitate was extracted with ether and divided into 0.3 g of soluble portion and 2.3 g of insoluble portion. The IR spectrum showed that the ether soluble content was mostly PDMS, with a small amount of poly(α-amino acid). On the other hand, the ether-insoluble portion consists of the desired graft copolymer, but contains a very small amount of poly[LYS
(Z)] cannot be excluded. Yield 87%. The IR spectrum of the ether-insoluble component (measured by forming a film on a KBR plate from a CH ₂ Cl ₂ solution) is shown in Figure 1. The symbols A to F in the figure indicate the following.

[Table] Absorption part The structure of this graft copolymer is estimated to be as follows based on the signal intensity ratio obtained by NMR measurement of a trifluoroacetic acid solution. This is expressed as PDMS-[Lys(Z)] ₂₇ . Production Example 2 In this example, the above amino side chain PDMS was used as the initiator polymer, and γ was used as the α-amino acid NCA.
-Benzyl-L-glutamate NCA [hereinafter Glu
(OBz)NCA] was used for graft copolymerization. 1.0 g of the above amino side chain PDMS and Glu (OB ₂ l)
Dissolve 5 g of each NCA in the polymerization solvent methylene chloride (tetrahydrofuran can also be used), add both solutions [Glu(OBzl)NCA concentration is 0.3M], and carefully shake.
The mixture was allowed to stand in a desiccator for 12 hours to polymerize. The product was separated using the same procedure as described in Production Example 1, yielding 0.5 g of ether soluble fraction and 4.6 g of insoluble fraction. The ether-insoluble component consists of a graft copolymer, but we cannot exclude the possibility that it contains a very small amount of poly[Glu(OBzl)]. Yield: 89.5%. IR spectrum of the ether-insoluble component (from methylene chloride solution to KBr plate) (measured by forming a film on top) is shown in Fig. 2. In the figure, the symbols A to F indicate the following.

[Table] Absorption part The structure of this graft copolymer is estimated to be as follows based on the signal intensity ratio obtained by NMR measurement of a deuterated chloroform solution. This is expressed as PDMS-[Glu (OBzl) ₇₆ . Production Example 3 In this example, the above amino side chain PDMS was used as the initiator polymer, and the α-amino acid NCA was
Graft polymerization was performed using SarNCA. Amino side chain PDMS 1g and sarcosine NCA (hereafter
(abbreviated as SarNCA) was dissolved in the polymerization solvent methylene chloride (the concentration of SarNCA was
After stirring carefully, the mixture was left in a desiccator for 12 hours to polymerize. The product was separated by the same operation as described in Production Example 1, and the ether soluble content was 0.07 g and the insoluble content was 1.8 g.
I got it. Although the ether-insoluble portion consists of a graft copolymer, we cannot exclude the possibility that it contains a very small amount of poly(Sar). Yield 96%. The IR spectrum of the ether-insoluble component (measured by forming a film on a KBr plate from a methylene chloride solution) is shown in Figure 3. The symbols A to D in the figure indicate the following.

[Table] Absorption area The structure of this graft copolymer is estimated to be as follows, calculated from the molar concentration ratio of SarNCA and amino side chain PDMS used in the polymerization. This is expressed as PDMS-(Star) ₄₅ . The degree of polymerization of the branched poly(α-amino acid) is determined by the ratio of the charged molar concentration of the α-amino acid NCA to the amine concentration of the amino side chain PDMS initiator. When the graft copolymers obtained in Production Examples 1, 2, and 3 were formed into a film from a dimethylformamide solution, a transparent, flexible, and strong film was obtained. PDMS and poly [Lys (Z) and poly [Glu (OBZl)]
The graft copolymer membrane of PDMS and poly(Sar) is stable even when immersed in water, but the graft copolymer membrane of PDMS and poly(Sar) is water-absorbing and swells significantly when immersed in water, losing its original shape. Examples of α-amino acids that can be used in producing the graft copolymer include alanine, glutamic acid γ-alkyl ester, aspartic acid β-alkyl ester, glycine, leucine, isoleucine, norleucine, ε-carbobenzoxylysine, γ- Examples include carbobenzoxyornithine, phenylalanine, O-benzylserine, valine, norvaline, proline, and sarcosine. Moreover, both optically active forms and racemic forms thereof can be used. When two types of α-amino acids NCA are added at the same time, a block in which two types of α-amino acids are randomly arranged is generated, but when a second α-amino acid NCA is added after the completion of polymerization of one NCA, two types of α-amino acids are formed. A block-like arrangement of α-amino acids is obtained. Next, an example of producing such a graft copolymer will be described. Production Example 4 In this example, the above amino side chain PDMS was used as the initiator polymer, and α-amino acid NCA was
Graft polymerization was performed using SarNCA, and then Glu(OBZl)NCA was added to perform graft polymerization. 1.0 g of amino side chain PDMS and 1.5 g of SarNCA were each dissolved in the polymerization solvent methylene chloride, and both solutions were combined (the concentration of SarNCA was 0.3 M), carefully shaken, and left in a desiccator for about 12 hours to polymerize. I let it happen. Thereafter, a methylene chloride solution of 1.0 g of Glu(OBzl) was added (the concentration of Glu(OBzl)NCA was approximately 0.15 M), and after being carefully shaken, the mixture was allowed to stand in a desiccator for approximately 12 hours to polymerize. The product was separated using the same procedure as described in Production Example 1, yielding 0.3 g of ether soluble fraction and 2.4 g of insoluble fraction. Although the ether-insoluble portion consists of a graft copolymer, it cannot be excluded that it may contain a very small amount of α-amino acid homopolymer and copolymer. Yield 88%. The IR spectrum of the ether-insoluble component (measured by forming a film on a KBr plate from a methylene chloride solution) is shown in Figure 4. The symbols A to G in the figure indicate the following.

[Table] The structure of this graft copolymer is estimated to be as follows, calculated from the molar concentration ratio of Glu(OBzl)NCA, SarNCA, and amino side chain PDMS used in the polymerization. This is expressed as PDMS - (Sar) ₄₅ - [Glu (OBzl)] ₁₃ . When the above graft copolymer was formed into a film from a dimethylformamide solution, a transparent, flexible and strong film was obtained. When this graft copolymer membrane is immersed in water, it swells to some extent, but unlike the graft copolymer of PDMS and polysarcosine described in Production Example 3, it does not swell violently and lose its shape. By grafting two types of poly(α-amino acids) in this manner, a membrane having appropriate hydrophilicity can be produced. (ii) Modification of poly(α-amino acid) (branches) of graft copolymer The graft copolymer synthesized in Production Example 1 contains a Lys (Z) polymer as a branch.
Furthermore, the graft copolymers synthesized in Production Examples 2 and 4 contain Glu (OBzl) polymers as branches. The side chains of these α-amino acid residues can be induced into heterologous structures by mild chemical treatments. The reaction equation for this process is as follows. By chemical modification of the side chains of poly(α-amino acid) branches, graft copolymer films with new properties can be synthesized. Examples of such reactions are described below. Reaction Example 1 Dissolve 0.5 g of graft copolymer PDMS-[Lys(Z)] ₂₀ synthesized according to the method of Production Example 1 in 10 ml of dimethylformamide, and add 25% HBr/
10 ml of ACOH was added and stirred at room temperature for 12 hours. The solution was concentrated, the resulting oil was well decanted with ether, the volatiles were distilled off again, and 1N NaOH was added to give a white material. This was washed with methanol and dried. The IR spectrum (KBr tablet method) of the reaction product is shown in Figure 5. Compared to the IR spectrum before the reaction (Figure 1),
The absorption of the urethane bond at 1685 cm ^-1 and the absorption based on the benzene ring at 700 cm ^-1 are weak, and Lys
It can be seen that the (Z) residue has been converted to a Lys residue. The structure of the reaction product is thought to be as follows. Reaction Example 2 Graft copolymer _PDMS- [Glu-(OBzl)] synthesized according to the method of Production Example 2.
Dissolved in ml dimethylformamide, 1NNaOH4
ml and stirred at room temperature for 5 minutes. The precipitated white substance was separated, washed with methanol, and then dried. The IR spectrum (KBr tablet method) of the reaction product is shown in the middle row of Figure 6. Compared to the IR spectrum before the reaction, the absorption based on the ester group at 1720 cm ^-1 and the absorption based on the benzene ring at 700 cm ^-1 disappear, and instead, an absorption based on the symmetric stretching vibration of the carboxylate group appears at around 1400 cm ^-1 . Appeared. The structure of the reaction product in this state is thought to be as follows. In the above formula, x+y=46, which is expressed as PDMS-[Glu(ONa)] ₁₉ . Next, water was added to the reaction mixture, and then 1N hydrochloric acid was added.
Adjust the pH to 4 and stir for 5 minutes. The precipitated white substance was thoroughly washed with water, further washed with acetone, and then dried. The IR spectrum (KBr tablet method) of the reaction product is shown in the lower part of Figure 6. here
Broad absorptions based on stretching vibrations of carboxylic acid OH groups appear near 3300 cm ^-1 and 2400 cm ^-1 . Therefore, the structure of the reaction product in this state is considered to be as follows. In the above formula, x+y=46, which is expressed as PDMS-[Glu(OH)] ₁₉ . If chemical modification can be applied only to the surface of the graft copolymer membrane, it is possible to apply a thin hydrophilic layer to the surface of a strong hydrophobic membrane. An example of surface modification by a heterogeneous reaction of a membrane is described below. Reaction Example 3 Graft copolymer PDMS-[Glu(OBzl)] ₂₄ synthesized according to the method of Production Example 2 was formed into a film from a dimethylformamide solution, and immersed in a mixed solution of 50 ml of 4N NaOH and 150 ml of methanol. The reaction was tracked by removing the membrane at regular intervals and measuring the attenuated total reflectance (ATR)-IR spectrum. Figure 7 shows the ATR-IR spectrum. The figure in the middle row shows the result after being immersed in the above alkaline bath for 80 minutes.
The ATR-IR spectrum shows that compared to the spectrum before the reaction shown in the upper row, the absorption based on the ester group at 1720 cm ^-1 and the absorption based on the benzene ring at 700 cm ^-1 disappear, and the carboxylate group appears instead at around 1400 cm ^-1 . Absorption based on symmetric stretching vibrations appeared. The surface structure of the film in this state is PDMS-[Glu(ONa)]
It is thought to be ₂₄ . Subsequently, the membrane was immersed in a mixture of 50 ml of 10% citric acid aqueous solution and 150 ml of methanol, and left for 20 minutes.
The ATR-IR spectrum of the film obtained in this way is shown in the lower part of Figure 7, and it is around 3300 cm ^-1 .
A broad absorption based on the stretching vibration of the carboxylic acid hydroxyl group appears around 2400 cm ^-1 . Therefore, the surface structure of the film in this state is PDMS-[Glu
(OH)] It is thought to be ₂₄ . (iii) Polydimethylsiloxane (stem) and poly(α-
Surface properties of a graft copolymer consisting of hydrophobic PDMS (trunk) and hydrophilic poly(α-amino acid) (branches) from a solution on a glass plate. When forming a film, it is thought that non-uniformity in the vertical distribution of hydrophobic blocks and hydrophilic blocks occurs within the completed film. That is, the membrane is an asymmetric membrane. Measurement Example 1 Graft copolymer prepared by the method of Production Example 2
PDMS—[Glu(OBzl)] ₂₄ was dissolved in dimethylformamide and cast onto a glass plate, and the solvent was slowly evaporated to form a film. Peel the film from the glass plate and check the composition of the air side surface and glass side surface using ATR.
Measured by IR method. The absorption intensity at 800 cm ^-1 of the bending vibration of the Si--Me bond is taken as the characteristic absorption of the PDMS segment, and the absorption intensity of the amide I absorption band at 1650 cm ^-1 is taken as the characteristic absorption of the poly[Glu(OBzl)] segment. The ratio of both components was evaluated using the ratio Z. Z on the air side of the membrane = 1.33, Z on the glass side of the membrane
= 2.61, and when the graft copolymer is formed into a film,
It can be seen that more PDMS segments gather on the glass side than on the air side. That is, from the graft copolymer synthesized by the method shown in Production Example 2,
Asymmetric membranes can be prepared by deposition from dimethylformamide solutions. In a graft copolymer consisting of hydrophobic PDMS (trunk) and hydrophilic poly(α-amino acid) (branches), the compatibility of both segments is low, so the solvent is distilled off from the solution to form a film. In this case, as the sample concentration increases, intramolecular micelles are first formed, followed by intermolecular micelles, and the micelle structure, that is, the phase-separated structure is maintained in the solid phase even after film formation. The resulting films may therefore have a heterogeneous surface structure (domain structure), which can be studied with transmission electron microscopy (TEM). Measurement Example 2 Graft copolymer PDMS-[Lys(Z)] ₂₇ and PDMS-[Lys(Z)] ₅₁ synthesized by the method of Production Example 1
Prepare a 0.5% dimethylformamide solution and drop a drop of it onto the sheet mesh of an electron microscope.
The solvent was evaporated at room temperature to obtain a thin film, which was observed by TEM. In the photo, the electron-dense PDMS segments appear black, and the poly(α-amino acid) segments appear white. Both graft copolymers showed a clear sea-island structure, and the development of a domain structure accompanied by microphase separation was observed. PDMS-(Lys(Z)) ₂₇ has a short poly[Lys(Z)] segment, so there are many black parts, whereas
In the TEM of PDMS-[Lys(Z)] ₅₁ , the proportions of black and white parts were almost equal. Hydrophobic as shown by TEM
By synthesizing a graft copolymer of PDMS (trunk) and hydrophilic poly[Lys(Z)] (branches), a surface-heterogeneous membrane with a developed domain structure due to microphase separation can be prepared. Furthermore, by changing the composition of the graft copolymer, the domain structure of the membrane can be adjusted. (iv) Polydimethylsiloxane (stem) and poly(α-
Antithrombotic properties of the (amino acid) (branch) graft copolymer: The results of measuring the antithrombotic properties of the graft copolymer of the present invention, as well as PDMS and α-amino acid homopolymer for comparison thereto will be shown. In this test, PDMS was applied directly to the surface of a watch glass, and other substances were first dissolved in dimethylformamide solvent (dissolve 300 mg of each sample in 8 ml of dimethyl formamide), and then placed on the watch glass and distilled off the solvent using an infrared lamp over about 2 hours. , dry overnight with a vacuum pump and use as a test sample. Also,
The sample whose surface was modified after film formation as shown in Reaction Example 3 in (ii) above was directly subjected to the antithrombotic test. Additionally, for comparison, a watch glass without any treatment, ie, just glass, was tested. The test method is as follows. Adult male dog (weight approx.
Take 30 ml of blood from the femoral artery of a patient (15 kg) and collect 4.5 ml of blood.
Add ACD solution (a solution consisting of citric acid, sodium citrate, and glucose) and add 0.2
ml to each sample prepared above on a watch glass and 0.02 ml of 0.1M aqueous calcium chloride solution added to initiate clotting. When each set time is reached, distilled water is added to stop blood clots, and the formed thrombus is fixed with formalin and replaced with distilled water. Remove the wet clot with a spatula, place it between tissue papers to absorb excess water, and weigh. The weight of the clot after 15 minutes when using glass
The thrombus formation rate was compared based on the weight percentage relative to 100%. Test Example 1 In this example, the antithrombotic properties of a graft copolymer of PDMS and poly[Glu(OBzl)] were tested.

【table】

[Table] Homopolymers such as PDMS and poly[Glu(OBzl)] exhibit better antithrombotic properties than glass. However, it can be seen that the graft copolymers (A), (B) and (C) in the table have even better antithrombotic properties than the homopolymers. Among graft copolymers with different compositions,
Poly[Glu
(OBzl)] The chain length of the branched polymer is not very long,
It can be seen that those that are not too short exhibit the best antithrombotic properties. Test Example 2 In this example, the antithrombotic properties of a graft copolymer of PDMS and poly[Lys(Z)] were tested.

【table】

[Table] A homopolymer of Lys (Z) dimethylsiloxane exhibits better antithrombotic properties than glass. However, it can be seen that these graft copolymers, namely (D), (E) and (F) in the table, have even better antithrombotic properties than the homopolymers. Among graft copolymers with different compositions,
Poly[Lys relative to chain length of PDMS backbone polymer
(Z)] It can be seen that branched polymers whose chain lengths are neither too long nor too short exhibit the best antithrombotic properties. Test Example 3 In this example, the antithrombotic properties of a graft copolymer of PDMS and poly(Sar) and a tertiary graft copolymer of PDMS, poly(Sar), and poly[Glu(OBzl)] were tested.

【table】

[Table] Graft copolymer of PDMS and poly(Sar) shows better antithrombotic properties than homopolymer PDMS.
It is on the same level as PDMS-[Glu(OBzl)]n graft copolymer. Poly(Sar) to PDMS stem polymer
A tertiary graft copolymer in which block copolymers of and poly[Glu(OBzl)] are bonded as branch polymers is
It can be seen that it exhibits even better antithrombotic properties than the binary graft copolymer. Test Example 4 In this example, PDMS (trunk) and poly[Glu(OBzl)] (branch) whose surface was modified according to the method of Reaction Example 3 in (ii)
The graft copolymer was tested for antithrombotic properties.

[Table] Graft copolymers have been shown to exhibit superior antithrombotic properties to their respective homopolymers; however, hydrolysis of the side chains of poly[Glu(OBzl)] segments further improves antithrombotic properties. It was shown that it improved. (v) Polydimethylsiloxane (stem) and poly(α-
Oxygen permeability of graft copolymers consisting of (amino acids) (branches). Polydimethylsiloxane is porous and has very high gas permeability in general, especially oxygen permeability.
Used as a material for artificial lungs. However, selectivity depending on the type of gas is low. hydrophobic
Graft copolymerization of poly(α-amino acid) to PDMS may relatively increase carbon dioxide permeability. However, even in this case, it is desirable to maintain oxygen permeability at a constant level. Here, it was synthesized using the method of Production Example 1 or 2.
PDMS and poly[Lys(Z)] or poly[Glu]
The oxygen permeability of the graft copolymer of (OBzl)] was measured and compared with that of various synthetic polymer membranes. An ethylcellulose membrane containing dispersed erythrosine, a dye that excites oxygen when exposed to light of an appropriate wavelength, and dimethylanthracene, an acceptor that reacts with the excited singlet oxygen, is sandwiched between sample films to be measured, and sealed in a large cell. The rate of disappearance of dimethylanthracene was tracked under atmospheric pressure to determine the amount of oxygen permeation. Membrane oxygen permeability coefficient cm ³ (STP), cm×10 ¹⁰ /cm ²・
sec・cmHg (27℃) Segmented polyaminoether urethane urea
4.20 (BzlCl quaternization) PDMS 606.4 PDMS-(Lys(Z)) ₃₃ 95.1(29℃) Poly[Lys(Z)] 0.080 PDMS-[Glu(OBzl)] ₁₉ 178.7 PDMS-[Glu(OBzl)] ₃₂ 96.5 PDMS―[Glu(OBzl)] ₅₈ 26.1 PDMS―[Glu(OBzl)] ₈₇ 2.90 PDMS―[Glu(OBzl)] ₁₄₆ 0.83 PDMS―[Glu(OBzl)] ₁₆₁ 0.76 Poly[Glu(OBzl)] 0.53 PD M.S. has a very high oxygen permeability, and poly(α-amino acid) has an extremely low oxygen permeability.
(OBzl)] as a branched polymer,
The oxygen permeability decreased, and it became clear that the oxygen permeability could be controlled by adjusting the composition of the graft copolymer. The oxygen permeability of graft copolymers with short poly(α-amino acid) branches is considerably greater. The reason why the graft copolymer of the present invention exhibits excellent antithrombotic properties as described above is due to the crystallinity, hydrophilicity, and rigidity of the poly(α-amino acid) block, and the amorphousness, hydrophobicity, and flexibility of the PDMS block. This is thought to be due to the development of a microphase-separated structure and a well-developed domain structure, and these structures control activation and promotion of platelet organization through selective interaction with blood proteins. it is conceivable that. Furthermore, the antithrombotic properties are increased by modifying the side chains of poly(α-amino acid) blocks because the modification increases the hydrophilicity of the membrane surface and lowers the interfacial free energy with blood. Conceivable. Based on the above-mentioned excellent performance, the antithrombotic material of the present invention can be used for various medical devices, materials, and other materials that require antithrombotic properties.
For example, it can be used in vascular catheters, extracorporeal blood transport circuits, and the like. In addition, due to its excellent oxygen permeability, it is used in various medical devices and materials that require both antithrombotic properties and oxygen permeability, such as gas exchange membranes for oxygenators, membranes for artificial skin, and contact lenses. It is possible. What has been explained above and shown in the specific examples of implementation are examples to help the understanding of the present invention, and the present invention is not limited to these examples, but is limited only by the scope of the claims. However, other changes and modifications may be made within this scope.

[Brief explanation of drawings]

Figure 1 shows the IR of the graft copolymer obtained in Production Example 1, namely PDMS-[Lys(Z)] ₂₇ .
The spectrum diagram, FIG.
(OBzl) ₇₆ IR spectrum diagram, Figure 3 is in the text,
The graft copolymer obtained in Production Example 3, namely
The IR spectrum of PDMS(Sar) ₄₅ , Figure 4 is in the main text, the IR spectrum of the graft copolymer produced by Production Example 4, namely PDMS-(Sar) _45- [Glu(OBzl)] ₁₃ .
The spectrum diagram, FIG. 5, is the graft copolymer obtained in Reaction Example 1, that is, PDMS-
(Lys) ₂₀ IR spectrum diagram, Figure 6 shows the change in IR spectrum due to chemical modification of the graft copolymer in Reaction Example 2 in the main text, and the upper row is
PDMS―[Glu(OBzl)] ₁₉ , middle row is PDMS―[Glu
(ONa)] ₁₉ , the lower row is an IR spectrum diagram of PDMS-[Glu(OH)] ₁₉ , and Figure 7 is the ATR-IR spectrum accompanying the surface modification of the graft copolymer film in Reaction Example 3 in the main text. This is a spectral diagram showing changes in the spectrum. The upper row shows the spectrum before surface modification treatment.
PDMS―[Glu(OBzl)] ₂₄ , the middle row is the one treated with alkali, i.e., PDMS—[Glu(ONa)] ₁₉ , the lower row is the one further treated with acid, i.e., PDMS—[Glu
(OH)] This concerns ₁₉ . In the charts of FIGS. 1 to 7, the vertical axis represents the wave number (cm ^-1 ), and the horizontal axis represents the transmittance.

Claims (1)

[Claims] 1. An antithrombotic material having gas permeability, which is composed mainly of a graft copolymer obtained by polymerizing α-amino acid N-carboxy anhydride with polydimethylsiloxane having an amino group in the side chain.