JPH0254376B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a film having an interpolymer complex on its surface and a method for producing the same. In recent years, research has become extremely active on novel composite polymer systems--polymer complexes that form complexes between different types of polymers using complementary intermolecular interactions and have properties different from those of the starting polymers. These inter-polymer complexes are based on electrostatic bonds between polymers with different charges, such as between polymer cations and polymer anions or between basic polymers and acidic polymers (polyion complexes). , complexes (hydrogen bonds, charge transfer bonds) formed between electron-donating to electron-withdrawing polymers, etc., and can be classified according to their interaction intermolecular forces. (See "Functional Polymers," Chapter 8, Kyoritsu Shuppansha) Here, a partner polymer that interacts with one polymer to form a complex is called a complementary polymer. These inter-polymer complexes are formed through cooperative interactions, so the reaction ends instantly and can be produced with extremely simple operations, and the resulting complexes are random, block copolymers, and graft copolymers. ,
Furthermore, since it is a polymer composite system with new properties different from polymer blends, it has attracted the attention of many researchers, and has already been used in ultrafiltration membranes, reverse osmosis membranes, contact lenses, antithrombotic materials, and various medical applications. Applied research on materials, etc. is being actively carried out, and some of it has already been put into practical use. Polymer complexes with such interesting properties are normally produced by mixing two types of polymer solutions, but this substance has various interesting functions as described above. However, the major drawback is that it lacks mechanical strength, which is what prevents it from being put to practical use more widely. Therefore, if the mechanical strength of a polymer composite can be increased by some method without losing its original properties, new possibilities of application will arise than ever before, and even new functions can be imparted. Based on the above idea, the present inventors have completed the present invention as a result of intensive studies to eliminate the conventional defects. An object of the present invention is to provide a film with excellent mechanical strength containing an inter-polymer complex in which a complementary polymer interacts with a graft polymer grafted onto a hydrophobic film, and a method for producing the same. The object of the present invention is to provide a hydrophobic film having an inter-polymer complex on its surface which is useful for ultrafiltration membranes, reverse osmosis membranes, antithrombotic materials, and various medical materials, and a method for producing the same. In the present invention, after a hydrophobic polymer forming a hydrophobic film is irradiated with ionized gas plasma, a hydrophilic unsaturated monomer is graft-polymerized on the surface of the hydrophilic film in the absence of the plasma. The method of the present invention involves irradiating the hydrophobic polymer forming the hydrophobic film with ionized gas plasma. Then, in the absence of the plasma, a hydrophilic film is prepared by graft polymerizing a hydrophilic unsaturated monomer, and the graft polymer obtained by the polymerization contains a complementary polymer having the ability to form an intermolecular complex. The method is characterized by forming the inter-polymer complex immersed in an aqueous solution. The hydrophobic film applied to the present invention may be any film formed from a hydrophobic polymer, but from the viewpoint of quality and cost, a hydrophobic film made of polyethylene, polypropylene, or polyethylene terephthalate is preferable. Porous films can also be used, such as those in which pores are formed by foaming or phase separation, those in which soluble components are dissolved and removed after film formation, or those in which pores are mechanically formed. For example, when the film is used as an ultrafiltration membrane or a reverse osmosis membrane, a porous film is preferred. The hydrophilic unsaturated monomer is not particularly limited as long as it has a vinyl group or an allyl group and is hydrophilic and can be subjected to normal radical polymerization. Generally acrylamide, methacrylamide,
N-vinylpyrrolidone; acrylic acid, methacrylic acid, P-styrenesulfonic acid, vinylsulfonic acid, 2-methacryloyloxyethylsulfonic acid, 3-methacryloyloxy-2-hydroxypropylsulfonic acid, allylsulfonic acid, methacrylsulfonic acid , and the ammonium salts and alkali metal salts of these acids, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoel methacrylate, hydrochloric acid, nitric acid, dimethyl sulfate, diethyl sulfate or It is a quaternized product of ethyl chloride. Preferred hydrophilic unsaturated monomers include acrylic acid, methacrylic acid, 2hydroxyethyl methacrylate, 2hydroxyethyl acrylate, acrylamide, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N,N dimethylaminoethyl methacrylate, or N , N dimethylaminoethyl acrylate. Furthermore, the graft polymerization rate in the graft polymerization in the present invention can be freely varied depending on the purpose and use, but is preferably at least 0.1% by weight, preferably 0.5% by weight based on the hydrophobic polymer forming the film.
That's all. The graft polymerization rate of the hydrophilized film of the present invention can be varied over a wide range depending on the purpose. For example, when improving wettability, adhesion, printability, or paintability, the graft polymerization rate is 0.1 to 5% by weight, ion exchange ability,
When imparting hygroscopicity or reactivity, or when used as a battery diaphragm, the graft polymerization rate is a few percent by weight to 100 percent by weight; when imparting water absorbency, ion exchangeability, cohesiveness, or metal trapping ability, the graft polymerization rate is %+ to 1000% by weight is used. Of course, it is also possible to use several thousand percent by weight exceeding this range. The polymerization in the present invention is so-called plasma initiated polymerization. That is, plasma-initiated polymerization is a method in which polymerization is initiated or active species are created using non-equilibrium ionized gas plasma, and most or all of the polymerization is completed in the absence of plasma. Generation of an ionized gas plasma can be accomplished by any of the known methods for generating plasma. For example, "Applied Techniques of Plasma Chemistry" by J. R. Hollahan and A. T. Bell, Wiley, New York 1974 and "Plasma Chemistry of Polymers" by M. Shen, Detzker. New York. Listed in 1976. That is, the monomer can be placed under vacuum between parallel plate electrodes connected to a high frequency generator, and the plasma can be generated using the parallel plates either outside or inside the vacuum chamber. Alternatively, an electric field may be created by an external induction coil to generate a plasma of ionized gas, or a plasma may be generated by placing oppositely charged electrodes spaced apart directly into a vacuum chamber. In the present invention, only a film made of a hydrophobic polymer is held in the presence of an ionized gas plasma, and then a hydrophilic unsaturated monomer is prepared in an aqueous solution of a hydrophilic unsaturated monomer in the absence of the plasma. be graft polymerized onto a film made of a hydrophobic polymer, or
Alternatively, polymerization of a film made of a hydrophobic polymer and an aqueous solution of a hydrophilic unsaturated monomer, or a film made of a hydrophobic polymer and a gas of a hydrophilic unsaturated monomer, is initiated in the presence of ionized gas plasma. Thereafter, the film is immersed in an aqueous solution of the monomer to perform graft polymerization onto the film in the absence of the plasma. Instead of polymerizing with an aqueous solution of a hydrophilic unsaturated monomer in the absence of an ionized gas plasma, an emulsion or an organic solvent solution in or of the monomer may be used. The complementary polymer of the graft polymer applied to the present invention is a polymer that forms an intermolecular complex with the graft polymer. For example, if the graft polymer is made of a monomer having a carboxylic acid group such as acrylic acid, methacrylic acid, or maleic anhydride, complementary polymers include polyethylene glycol, polyvinylpyrrolidone, polyxylyl viologen, and polyethyleneimine. and polyvinylpyridinium chloride. In addition, if the graft polymer is a polymer consisting of a basic monomer such as acrylamide, methacrylamide, vinylpyridine, N,N-dimethylaminoethyl methacrylate or N,N-dimethylaminoethyl acrylate, the complementary polymer is Examples include polyacrylic acid, polymethacrylic acid, poly2-acrylamido-2methylpropanesulfonic acid, polystyrenesulfonic acid, and polyvinylsulfonic acid.
When the film and the complementary polymer are immersed in an aqueous solution for a predetermined period of time, an interpolymer complex is formed. Further, the amount of complementary polymer is generally controlled by the amount of graft polymer to the film; for example, if the amount of graft polymer is large, a large amount of complementary polymer is also required. That is, since an amount of the complementary polymer that forms a complex with the graft polymer is attached to the film, it is sufficient to form the complex in an aqueous solution containing a large excess of the complementary polymer. To explain in more detail in the method of the present invention, degassing is
A film made of a hydrophobic polymer is irradiated with plasma using the above method at a pressure of 10 ^{-1 to} 10 ^-4 Torr. Preferably 20 to 200 watts, more preferably 40 to 100 watts
Glow discharge is caused to generate active species in the hydrophobic polymer. The irradiation time is usually 1 to 3600 seconds, preferably 10 to 1800 seconds. After plasma irradiation, when the film is polymerized in an aqueous solution of a hydrophilic unsaturated monomer in the absence of the plasma, the monomer is consumed by the active species of the film. So-called graft polymerization begins. The post-polymerization temperature and time vary depending on the type of monomer used and are not particularly limited, but the usual temperature is 1.
~60°C time of 1 to 25 hours is sufficient. Depending on the type of monomer, if the temperature exceeds 60°C, thermal polymerization may occur and low-molecular polymers may also be produced, so care must be taken. The graft-polymerized film is immersed in an aqueous solution containing a complementary polymer to form an interpolymer complex. The concentration of the complementary polymer varies depending on the grafting rate of the film and the type of polymer, but is usually 0.01~
The concentration is 1 molar. The temperature during dipping is not particularly limited, and for example, in the case of room temperature, the mixture is left under stirring for about 15 minutes to 1 hour. Moreover, an inorganic compound such as common salt can be added to the aqueous solution to increase the ionic strength.
The pH of the aqueous solution is adjusted depending on the type of complementary polymer to facilitate complex formation. After immersion, it is washed with water and dried if necessary, but drying is usually carried out at room temperature and under reduced pressure if necessary. The film of the present invention has excellent mechanical strength, and also has excellent hydrophilicity, water absorption, hygroscopicity, adhesion, printability, or metal collection property, so it can be used, for example, as an ultrafiltration film.
It can be applied to reverse osmosis membranes, antithrombotic materials and various medical materials. The present invention will be explained in detail below with reference to Examples. In the examples, the grafting rate and water contact angle were measured by the following methods. a Grafting rate Grafting rate is calculated by weight after drying by washing the grafted film with stirring in a good solvent for 2 days to completely remove unreacted monomers and homopolymers Grafting rate (%) = After treatment Film weight - Initial film weight / Initial film weight x 100 b Water contact angle Measured using a contact angle meter model CA-P manufactured by Kyowa Kagaku Co., Ltd. Example 1 A square polyethylene film with a thickness of 50 μm and a side of 15 mm was placed on the wall of a separable flask with an inner diameter of 35 mm at 10 ^-3 Torr, and was placed between two copper electrode plates connected to a 13.56 MHz high frequency generator. insert
Generate and irradiate plasma for 90 seconds with an output of 100W,
Thereafter, a 50% by weight aqueous solution of acrylic acid in 10 ^-3 torr was added and post-polymerized for 12 hours at 25°C. The obtained graft film was washed with stirring in pure water for 2 days, the solvent was removed, and dried to make a sample. When the contact angle of water was measured, it was significantly hydrophilic at 56° compared to 101° for the original polyethylene film. The graft rate was 24%. The graft film was placed in 25 ml of a 5% by weight aqueous solution of polyvinylbenzyltrimethylammonium chloride (hereinafter abbreviated as PVB) (molecular weight 43,000) for 30 minutes while stirring to perform an inter-polymer complex formation reaction. Next, this film was thoroughly washed with water, dried in vacuum, and weighed.As the weight increased, the complex-formed PVB was compared to the grafted polyacrylic acid.
It was 60% by weight. Further, when the nitrogen content of this film was calculated by elemental analysis, the PVB content was 19 mol % based on the polyacrylic acid. When the contact angle of this film with water was measured, it was 0°. Example 2 An acrylic acid-grafted polyethylene film similar to that used in Example 1 was placed in 100 ml of 0.1N sodium hydroxide aqueous solution and stirred at room temperature for 15 minutes, and then immersed in the same PVB aqueous solution as in Example 1. When dried, the PVB was 285% by weight based on the grafted polyacrylic acid. Further, the nitrogen content of this film was calculated by elemental analysis to be 95 mol%, and the contact angle of water was 0°. Example 3 Using the same film, equipment, and experimental conditions as in Example 1, complex formation between the graft polymer and its complementary polymer as shown below was performed, and the results shown in Table 1 were obtained. was gotten.

【table】

[Table] Example 4 Dry acrylic acid obtained in Example 3 No.5/
PVB to AMPS grafted polyethylene film
Add 3 grams of complexed film to 150 ml of pure water.
After soaking for 12 hours, it was taken out of the water, lightly touched with paper, and the water droplets on the surface were removed using a film. When the weight was weighed, it weighed 75 grams. This revealed that this film had the ability to absorb approximately 25 times more water. The ungrafted polyethylene had almost no water absorption capacity. Example 5 One gram of the dried acrylic acid-grafted polyethylene film obtained in Example 3 No. 4 complexed with polyethyleneimine was mixed with 6.2 ml of Cu ²⁺ .
Approximately 75% when immersed in 50ml of ×10 ^-3 molar aqueous solution
of Cu ²⁺ was adsorbed.

Claims (1)

[Scope of Claims] 1. The surface of a hydrophilic film in which a hydrophobic polymer forming a hydrophobic film is irradiated with ionized gas plasma, and then a hydrophilic unsaturated monomer is graft-polymerized in the absence of the plasma. A film in which an interpolymer complex is formed between the graft polymer obtained by the polymerization and its complementary polymer. 2. The film according to claim 1, wherein the hydrophobic polymer is polyethylene, polypropylene, or polyethylene terephthalate. 3 The hydrophilic unsaturated monomer is acrylic acid, methacrylic acid, 2hydroxyethyl methacrylate, 2hydroxyethyl acrylate, acrylamide,
The film according to claim 1, which is methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N,N dimethylaminoethyl methacrylate, or N,N dimethylaminoethyl acrylate. 4. The film according to claim 1, wherein the graft ratio of the graft polymerization is at least 0.1% by weight based on the hydrophobic polymer forming the film. 5. The film according to claim 1, wherein the complementary polymer is polyethylene glycol, polyxylylviologen, or polyethyleneimine. 6. The film according to claim 1, wherein the complementary polymer is polyacrylic acid, polymethacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, polystyrenesulfonic acid, or polyvinylsulfonic acid. 7. The film according to claim 1, wherein the amount of the complementary polymer is at least equimolar in repeating units to the grafted polymer. 8 After irradiating the hydrophobic polymer forming the hydrophobic film with ionized gas plasma, a hydrophilic film obtained by graft polymerizing a hydrophilic unsaturated monomer in the absence of the plasma is obtained by the polymerization. 1. A method for producing a film having an inter-polymer complex on its surface, which comprises immersing the film in an aqueous solution containing a graft polymer and a complementary polymer capable of forming an inter-polymer complex to form the inter-polymer complex. 9. The method according to claim 8, wherein the hydrophobic polymer is polyethylene, polypropylene or polyethylene terephthalate. 10 The hydrophilic unsaturated monomer is acrylic acid, methacrylic acid, 2-hydroxyethyl methacrylate, 2
Hydroxyethyl acrylate, acrylamide, methacrylamide, 2-acrylamide-2-
Claim 8 which is methylpropanesulfonic acid, N,N dimethylaminoethyl methacrylate or N,N dimethylaminoethyl acrylate
The method described in section. 11 Grafting ratio in graft polymerization is at least 0.1% by weight based on the hydrophobic polymer forming the film
The method according to claim 8. 12 Complementary polymer is polyethylene glycol,
9. The method according to claim 8, which is polyxylylviologen or polyethyleneimine. 13. The method according to claim 8, wherein the complementary polymer is polyacrylic acid, polymethacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, polystyrene sulfonic acid, or polyvinylsulfonic acid. 14. The method according to claim 8, wherein the amount of the complementary polymer is at least equimolar in repeating units to the grafted polymer.