RU2738607C1 - Method of producing low-density super-cross-linked monolithic polymers - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of high-porous low-density polymer materials. Method of producing low-density super cross-linked polymers by cross-linking polymer chains in polymer solutions in an organic solvent from the class of chloroalkanes with bifunctional cross-agents in the presence of a Friedel-Crafts catalyst differs from the closest analogue in that monolithic samples of high-porous mesh polymers with low density are used: rigid-chain linear polymers containing aromatic rings: poly-alpha-methylstyrene, oligophenylmethylsiloxane, poly-2-vinylnaphthalene, poly-N-vinylcarbazole, polyacenaphthylene; method includes cross-linking polymer chains in polymer solutions with concentration of 1–2 wt. %; bifunctional cross-linking compounds used are bis-chloromethyl derivatives of diphenyl or benzene in amount of 1.5–2 mol per 1 mole of the repeating unit of the polymer; solvent is removed from polymer organic gels after synthesis by lyophilic drying from benzene and by supercritical drying from carbon dioxide.

EFFECT: invention increases porosity, specific surface area and micropore volume.

1 cl, 4 tbl, 6 ex, 2 dwg

Description

The technical field to which the invention relates

The invention relates to the field of obtaining highly porous polymeric materials of low density used in sorption technologies, in gas-liquid chromatography, in gas separation processes, in experimental studies related to the problem of inertial thermonuclear fusion (ICF) (interaction of substances with high-power radiation - laser and ion).

State of the art

Obtaining and intensive research of new types of microporous and mesoporous polymers naturally leads to the expansion of the field of their practical use, in particular for sorption and separation of gases, as catalysts, substrate sensors, in chromatography, in various industrial sorption technologies (water purification, selective sorption of biological active and other organic compounds in the pharmaceutical industry). Investigation of physical processes in the interaction of high-power laser radiation with porous materials of various classes is a new area of application for porous polymers. These studies are one of the important areas of experimental and theoretical research for solving the problems of inertial thermonuclear fusion (ITS). Therefore, the creation of new highly porous materials for laser targets is of great fundamental and applied importance. Such materials are necessary to create a stable process of target implosion at the boundary of the density jump, as well as to increase the efficiency of microexplosions and thermonuclear combustion. New materials for laser targets should have special properties - a nanoporous structure and a uniform density gradient in the microscale of the laser target. Of particular interest are polymeric materials with a low density (from 200 to 0.5 mg / cm ³ ) required for experiments in laser and heavy-ion inertial synthesis [Orekhov AS, Akunets AA, Borisenko LA, Gromov AI, Merkuliev Yu. A., Pimenov VG Modern trends in low-density materials for fusion / Journal of Physics: Conference Series (2016) 012080, doi: 10.1088 / 1742-6596 / 688/1/012080; Kaur Ch., Chaurasia Sh., Borisenko NG, Orekhov AS, Leshma P., Pimenov VG, Sklizkov GV Interaction of high-power laser radiation with low-density polymer aerogels / Quantum electronics, 2017, 47, N6, p. 495-502. doi: 10.1070 / QEL16292].

Studies of plasma formation processes under the action of intense laser radiation with low-density media have shown a significant effect of the structural features of the target material on the plasma stability. At the same time, the processes of formation and development of hydrodynamic disturbances in plasma are associated with the structure of the material: the size of structural elements, the size of the cells-voids, their geometric shape, etc. Currently, in laser experiments, metal, for example, berryl foams, carbon and polymer low-density materials (PMM), mainly based on cellulose ethers, acrylate and resorcinol-formaldehyde compositions are widely used [Nagai K., Musgrave CSA, Nazarov W. A review of low density porous materials used in laser plasma experiments / Physics of plasma, 2018, 25, 030501. doi: 10.1063 / 1.5009689].

The main advantage of "polymer foams" is the extremely low density of the samples, up to 0.5 mg / cm ³ , which makes it possible to carry out experiments on the currently operating laser facilities. At the same time, most of the known PMMs have a fibrous structure with an inhomogeneous distribution of structural elements and void cells (pores) in space, which can provoke the development of plasma instability when such materials are exposed to a laser pulse. In this regard, the search for new PMMs with a homogeneous microcellular structure is urgent.

Porous crosslinked polymers are well known and find various applications [Hodge P., Sherrington D.C. Syntheses and Separations using Functional Polymers. Wiley, New York, 1989; Yu C., Xu M.C., Svec F., Frechet J. MJ. / J. Polym. ScL, Polym. Chem. 2002, 40, p. 755-769]. Unlike gel polymers with a low degree of crosslinking, which become porous when swollen in solvents, highly crosslinked polymers have a permanent porous structure that forms during their synthesis and remains dry [Sherrington D.C. / Chem. Commun. 1998, p. 2275-2286]. In modern methods of high performance liquid chromatography (HPLC), columns filled with porous polymer beads are often used [Xu M.S., Brahmachary E., Janco M., Ling F.H., Svec F., Frechet J.M.J. / J. Chromatogr. A, 2001, 928, p. 25-40]. In such columns, the flow of the mobile phase passes relatively unimpeded between the granules, while the movement of liquid in the porous structure of the granules themselves is hindered. For large molecules, diffusion into the pores can be very slow, which causes a significant expansion of the recorded chromatographic peak. Long columns are used to increase the separation efficiency of a mixture of organic compounds with high molecular weight. In addition, the flow rates must be low, which significantly increases the analysis time. A promising approach to solving this problem was the use of porous monolithic polymers [Svec F., Frechet J.M. J. Science 1996,273,205-211; Peters E.C., Svec F., Frechet J.M.J. / Adv. Mater. 1999, 11, p. 1169-1181]. Such polymeric materials are used in analytical chemistry, including high performance liquid and membrane chromatography [US patent No. 8586641, publ. 11/19/2013; Xie S., Svec F., Frechet J.M.J. / J. Chromatogr. A 1997, 775, p. 65-72; Tennikov M.B., Gazdina N.V., Tennikova T. B., Svec F. / J. Chromatogr. A 1998, 798, p. 55-64], capillary electrochromatography [Peters E.C., Petro M., Svec F., Frechet J.M.J. / Anal. Chem. 1997, 69, p. 3646-3649], microfluidics [Yu C., Xu M.C., Svec F., Frechet J.M.J. / J. Polym. Sci. Polym. Chem. 2002, 40, p. 755-769], molecular imprinting [Whitcombe M.J., Vulfson E.N. / Adv. Mater. 2001, 13, p. 467-478] high-performance bioreactors [Petro M., Svec F., Frechet J. M.J. / Biotechnol. Bioeng. 1996, 49, p. 355-363].

Among the known porous polymeric materials, hypercrosslinked polymers occupy a special place, since they are fundamentally new polymeric materials with unique properties.

A method for producing hypercrosslinked styrene polymers was first proposed by V.A. Davankov, M.P. Tsyurupa. and Rogozin S.The. [US patent No. 3729457, publ. 04.24.1973]. Hypercrosslinked styrene polymers, in this patent called macroreticular styrene polymers, were obtained by crosslinking linear polystyrene chains in solution with bifunctional reagents (bis (chloromethyl) diphenyl, para-xylylene dichloride) according to the Friedel-Crafts reaction. To obtain hypercrosslinked polystyrene in another patent [USSR author's certificate No. 948110, publ. 04/23/1983] the authors use the less toxic cross-agent dimethylformal.

In the dry state, hypercrosslinked polystyrenes have a low density (high porosity) due to the loose packing of chains in a rigid and homogeneous polymer network formed prior to the onset of phase separation during synthesis. The structure of these sorbents is a polymer network having a vast inner surface (up to 1900 m ² / g) and swellable in any of organic and inorganic solvents, as well as, most importantly, having a stable set of nanopores (1,5-50 nm, depending on the type of sorbent) [mentioned US patent No. 3729457; Davankov VA, Tsyurupa M.R. Structure and properties of hypercrosslinked polystyrene - the first representative of a new class of polymer networks / Reactive Polym., 1990, v. 13, p. 27-43; Davankov VA, Tsyurupa MP Structure and properties of porous hypercrosslinked polystyrene sorbents Styrosorb / Pure and Appl. Chem. 1989, V. 61, N11, p. 1881-1888; Tsyurupa MP, Davankov VA Porous structure of hypercrosslinked polystyrene: State-of-the-art mini-review / Reactive & Functional Polymers. 2006, 66, p. 768-779].

Hypercrosslinked polystyrenes have a uniquely high sorption capacity in relation to organic substances in aqueous or air environments. They have found wide application for the concentration of trace impurities, as well as in large-scale sorption processes in the food, chemical, medical industry [Davankov V.A., Tsyurupa MR, "Hypercrosslinked Polymeric Networks and Adsorbing Materials". Elsevier, Amsterdam, Boston, etc., 2011. 670 p]. Currently, the production of industrial hypercrosslinked polymer sorbents is based on the traditional method of crosslinking styrene-divinylbenzene copolymers using bifunctional cross-agents [Purolite Product Guide. Characteristics and Application. Product Guide Rev 01/12. Purolite Company. 2011.20 p .; Polymeric Adsorbent Resins for Industrial Applications. Purolite, 2017, 40 p].

The possibility of practical use in hydrometallurgy of granular hypercrosslinked polystyrenes, for example for the extraction of rhenium from uranium-containing solutions, is described in patents [RF patent No. 2294391, publ. 27.02. 2007; RF patent No. 2227170, publ. 04/20/2004].

It is proposed to use hypercrosslinked polystyrenes as sorbents for the purification of mineralized aqueous solutions of caprolactam production from organic compounds [RF patent №2403208, publ. 10.11.2010].

Another area of practical use of hypercrosslinked polystyrenes is biomedicine. Granular hypercrosslinked polystyrenes with a modified surface turned out to be effective bio- and hemocompatible sorbents when used in hemosorption techniques for the extraction of highly toxic organic compounds (molecular weight from 100 to 20,000) from blood plasma of patients with sepsis, uremia, etc. [RF patent No. 2089283, publ. 1997].

Recently, similar hypercrosslinked polymer networks have become known, which are formed by spatial crosslinking not of polymer chains, but of benzene, thiophene, pyrrole molecules [Lee JM, Briggs ME, Hasell T., Cooper AI / Adv. Mater. 2016, 28, p. 9804-9810; Wang HL, Chen JL, Zhang QX / Adsorpt. Sci. Technol. 2006, 24, p. 17-28]. The resulting hypercrosslinked polymers have a high inner surface of up to 1400 m ² / g and a large pore volume of up to 1.5 cm ³ / g, if the starting "monomer" is benzene. In polymer networks based on thiophene or pyrrole, the porous structure turned out to be less developed - the inner surface did not exceed 480 and 320 m ² / g, and the total pore volume was 0.3 and 0.2 cm ³ / g, respectively. The micropore volume for these three polymer networks was 27, 73, 56% of the total pore volume. The pore size in the polymers according to the data of low-temperature nitrogen sorption was 0.9-1.5 nm. Other hypercrosslinked grid having a high internal surface to 1800 m ² / g, were obtained from derivatives of carbazole [X. Yang, M. Yu, Y. Zhao, C. Zhang, X. Wang, JX Jiang / RSC Advances, 2014, 4, p. 61051-61055; L. Pan, Q. Chen, JH Zhu, J.-G. Yu, YJ He, BH Han / Polym. Chem., 2015, 6, p. 2478-2487], fluorene and its derivatives [MG Schwab, A. Lennert, J. Pahnke, G. Jonschker, M. Koch, I. Senkovska, M. Rehahn, S. Kaskel / J. Mater. Chem., 2011, 21, p. 2131-2135]. Hypercrosslinked networks based on tetraphenylethylene were also obtained by crosslinking with dimethyl acetal [S. Yao, X. Yang, M. Yu, Y. Zhang, JX Jiang / J. Mater. Chem. A, 2014, 2, p. 8054-8059]. Such hypercrosslinked networks have a significant drawback limiting their use as technological sorption materials, since they are obtained only in the form of small particles of irregular shape.

All of the above methods for obtaining highly porous polymers are very effective, but have a significant drawback - the density of the samples exceeds the required level for laser target materials (less than 100 mg / cm ³ ), and they cannot be obtained in the form of block samples.

Analyzing the synthesis methods and properties of various types of hypercrosslinked polymers, the authors assumed that the formation of rigid networks in the presence of a large amount of a "good" solvent, at a polymer concentration of less than a few percent, will lead to the production of frame-structured highly porous polymers with the required low density, less than 100 mg / cm ³ . The formation of a sufficiently strong polymer xerogel of low density will become possible when crosslinking rigid-chain linear polymers (polyvinylnaphthalene, polyacenaphthylene, poly-alpha-methylstyrene, polyphenylmethylsiloxane, etc.) from low-concentration solutions in solvents of the chloroalkane class. Such polymers will have a developed micro-mesoporous structure. Obtaining blocks of low-density polymer xerogels required for the manufacture of a laser target will become possible using the methods of sublimation and supercritical drying of materials.

At present, such polymeric materials are not produced, and the use of low-density cellulose-based materials for laser targets is limited by the complexity of the production process and the high fragility of such xerogels.

An analogue of the present invention is the aforementioned RF patent No. 2089283, in which only granular hypercrosslinked polystyrenes with a specific surface area of up to 1900 m ² / g are obtained. The copolymers of styrene with divinylbenzene swollen in dichloroethane are crosslinked with monochlorodimethyl ether or p-xylylene dichloride. According to another method, polymers are obtained by "self-linking" of macrochains of chloromethylated copolymers of styrene with divinylbenzene in the presence of a Friedel-Crafts catalyst. In the examples given, there are no special techniques for obtaining low-density materials using freeze-drying or supercritical drying. Also, no pore-forming substances are introduced. Therefore, the density of the resulting granular samples cannot be lower than 500 mg / cm ³ . A common feature of this method for producing hypercrosslinked polymers and the method according to the present invention is the use of p-xylylene dichloride as a cross-agent when crosslinking polymer chains with benzene groups.

Another analogue is the aforementioned USSR Inventor's Certificate No. 948110, which describes the production of hypercrosslinked polystyrenes obtained by crosslinking linear polystyrene chains in solution, or swollen copolymers of styrene with divinylbenzene with a bifunctional cross-agent dimethylformal. Dimethylformal, reacting with benzene groups of neighboring polymer chains, upon initiation with a catalyst - aluminum, zinc, iron or tin chloride, forms bridging crosslinks with methylene groups. The final product is obtained in the form of fine particles. The density of such materials cannot be less than 500 mg / cm ³ , since no special drying methods are used and no pore-forming agents are introduced. A common feature of this process for producing hypercrosslinked polymers and the process of the present invention is the use of one type of Friedel-Crafts catalyst, tin tetrachloride.

The closest to the proposed method for producing hypercrosslinked polymers of the monolithic type in terms of its essential features is a method for producing hypercrosslinked polystyrenes of the monolithic type, including the process of forming a three-dimensional polymer when crosslinking macrochains of linear polystyrene in solution with bifunctional cross-agents [the aforementioned US patent No. This method produces highly porous polymers with a specific surface area of up to 1500 m ² / g. A common feature of this method for producing hypercrosslinked polymers and the method according to the present invention is the use of the same type of crosslinking reagents - p-xylylene dichloride and bis (chloromethyl) -biphenyl and a solvent - dichloroethane. Since the polymer organogel block is destroyed during synthesis due to the high exothermicity of the crosslinking reaction in a concentrated polystyrene solution (about 10 wt%), as well as at the stage of washing, the final product is obtained in the form of small particles of irregular shape. Drying of samples is carried out after rinsing with water. The apparent density of the obtained polymers is not less than 700 mg / cm ³ .

Disclosure of invention

The objective of the present invention is to obtain samples of highly porous low-density polymers of monolithic type with a specific surface of more than 1000 m ² / g and a density of less than 500 mg / cm ³ for the manufacture of laser targets necessary for research in the field of inertial thermonuclear fusion, as well as for use in sorption technologies ( absorption and separation of gases, etc.). The technical result achieved in this case is to expand the functionality.

The problem is solved with the achievement of the specified technical result due to the proposed method for obtaining low-density hypercrosslinked polymers by crosslinking polymer chains in polymer solutions in an organic solvent from the class of chloroalkanes with bifunctional cross-agents in the presence of a Friedel-Crafts catalyst, characterized in that for obtaining monolithic samples of highly porous network polymers with low density: use rigid-chain polymers of linear structure containing aromatic rings: poly-alpha-methylstyrene, oligophenylmethylsiloxane, poly-2-vinylnaphthalene, poly-N-vinylcarbazole, polyacenaphthylene; carry out a crosslinking reaction of polymer chains in polymer solutions with a concentration of 1-2 wt. %; bis-chloromethyl derivatives of biphenyl or benzene are used as bifunctional cross-linking compounds in an amount of 1.5-2 mol per 1 mol of the repeating unit of the polymer; the solvent is removed from polymer organic gels after synthesis by freeze drying from benzene and by supercritical drying from carbon dioxide.

Brief Description of Drawings

FIG. 1 shows the isotherms of nitrogen sorption and desorption at 77 K for the PAMS-2 hypercrosslinked polymer.

FIG. 2 shows the isotherms of nitrogen sorption and desorption at 77 K for the OPMS hypercrosslinked polymer.

In both cases, bis- (chloromethyl) -biphenyl 1.5 mol was used as a cross-agent. In both figures, reference numbers mean: 1 - drying from water, 2 - supercritical drying method in carbon dioxide.

Detailed description of the invention

To obtain hypercrosslinked networks based on poly-alpha-methylstyrene (PAMS), we used samples of polymer with a molecular weight of 8000 (manufactured by abcr GmbH in Germany) and high-molecular weight PAMS synthesized by low-temperature cationic polymerization in methylene chloride. Among the samples synthesized under various conditions, PAMS with an average molecular weight of 350,000 was chosen to obtain crosslinked polymers. The molecular weight distribution was determined by gel permeation chromatography.

All polymer networks are obtained as a result of the Friedel-Crafts reaction of side aromatic fragments of polymer chains with bifunctional cross-agents, p-xylylene dichloride and bis (chloromethyl) -biphenyl. The crosslinking reaction is carried out in an organic solvent, dichloroethane, at a concentration of the initial polymer of 1-2%. After synthesis, the blocks of swollen hypercrosslinked polymers are washed with acetone in a Soxhlet extractor and then dried in a supercritical drying unit in carbon dioxide, or washed with benzene and dried by freeze drying in a vacuum. To compare the properties of the materials obtained, some of the samples after synthesis and extraction with acetone were washed with water and dried at 70-80 ° C, by analogy with the drying method in the closest analogue.

Studies of the porous structure of the obtained hypercrosslinked low-density polymers were carried out by the method of low-temperature adsorption of nitrogen on a Nova-1200e installation (Figs. 1, 2). Found that all the investigated polymer networks have developed porous structure (Table 1-3.) Having a specific surface area up to 1700 m ² / g (BET method of calculation). Among all synthesized polymers, hypercrosslinked poly-acenaphthylene has a maximum total pore volume of 5.5 cm ³ / g, at a relative nitrogen pressure of 0.98.

All synthesized hypercrosslinked polymers dried from a solvent (acetone) under supercritical drying in carbon dioxide are characterized by high values of the porous structure parameters (Tables 1, 2). The specific surface area and volume of micropores increase 1.5 times for a polymer based on PAMS-2, 1.4 times for PAN, 1.3 times for OFMS and PAMS-1, 1.2 times for PVN, when changing the method drying, from water to supercritical drying in carbon dioxide. In this case, the total pore volume increases more sharply, 5 times for the polymer based on OFMS, 3.3 times for PAN, 3.2 times for PAMS-2, 2.8 times for PAMS-1, and 1.9 times times for PVN. Replacing the drying method from water to carbon dioxide allows one to obtain low-density materials with an apparent density of up to 100 mg / cm ³ (Tables 1, 2).

After replacing acetone with water in polymers after synthesis and subsequent heating (70-80 ° C - 24 hours), it turned out that the total pore volume for all polymer samples is several times less than during supercritical drying. At the same time, among all polymer samples dried from water, a polymer based on polyacenaphthylene also stands out. After crosslinking this polymer with p-xylylene dichloride, the pore volume in the material reaches 2.6 cm ³ / g (Table 3).

The specific surface area, the micropore volume and the total pore volume is reduced (the surface 100 ^m2 / g) for the polymer based on PAMS PAMS-1 and-2 by replacing the drying method from water to freeze drying from benzene. At the same time, the density of the samples is significantly reduced, to 0.06 g / cm ³ for the polymer based on PAMS-2, since the evaporation of benzene crystallites leads to the formation of large micron-sized macropores. In contrast to homogeneous hypercrosslinked polymers after supercritical drying, such samples are foam-like materials. Thin transparent walls in the samples have a microporous structure, since the specific surface area reaches high values, up to 800 m ² / g.

The synthesized hypercrosslinked polymers proved to be good sorption materials capable of retaining a significant amount of water and organic solvents (Table 4).

The essence of the invention is illustrated by the following examples.

Example 1

Obtaining hypercrosslinked poly-alpha-methylstyrene

0.125 g of poly-alpha-methylstyrene (M _w = 8000) (PAMS-1) was dissolved in a conical flask with 10 ml of dichloroethane using an ultrasonic water bath, 0.133 g (0.5 mol per 1 mol of polymer unit) bis (chloromethyl) biphenyl, and after its complete dissolution, 0.12 ml of stannous chloride was introduced with stirring. The reaction mixture was kept for 24 hours at room temperature, and then at 60 ° C and 70 ° C for 24 hours (under reflux). The polymer gel block was cut into large pieces and 10 ml of acetone was injected. A solution of acetone with dichloroethane and catalyst residues was removed, 15 ml of acetone and 1 ml of HCL _conc. ... The next day, the polymer was washed 2 times with acetone and then washed with acetone in a Soxhlet extractor for 8-10 hours. The resulting polymer, swollen in acetone, was stored under a layer of solvent, and a part of the polymer was repeatedly washed with water and dried at 70-80 ° C for a day. Part of the polymer gel was washed with benzene and dried by freeze-drying in a vacuum. A portion of the gel was placed in a supercritical dryer and the solvent was removed with carbon dioxide. The obtained polymer samples were additionally dried from traces of acetone at 70 ° C for a day. Polymers with 1.0 and 1.5 mol of bis (chloromethyl) diphenyl per mol of polymer unit were obtained in a similar way. Catalyst stannous chloride 2 mol per mol of cross-agent.

Example 2

Obtaining hypercrosslinked high molecular weight poly-alpha-methylstyrene

Analogously to example 1, using the synthesized high molecular weight poly-alpha-methylstyrene (PAMS-2) (according to gel permeation chromatography M _w = 350,000). The amount of the cross-agent is from 0.5 to 2 mol per 1 mol of the polymer unit, the catalyst is 2 mol per 1 mol of the cross-agent.

Synthesis of high molecular weight poly-alpha-methylstyrene

The alpha-methylstyrene monomer was purified from the inhibitor by passing through a small glass column (D = 1 cm, L = 15 cm) with a porous bottom, filled with silica gel for chromatography (particle size 60-200 μm) (layer height 9 cm). Into a three-necked flask with a central two-blade stirrer, a thermometer and a tube for introducing an inert gas, 230 ml of methylene chloride (without additional purification) and 35 ml of monomer were introduced, the supply of an inert argon gas was switched on. The mixture was cooled to -70 ° C. Catalyst 48% boron trifluoride solution in diethyl ether was diluted with methylene chloride (5 ml), cooled to -27 ° C and gradually introduced into the monomer solution with vigorous stirring. After introducing the catalyst, the mixture was stirred for 1 hour until a block was formed, and then kept at -70 ÷ -75 ° C for 40 min. After thawing the reaction mixture to room temperature, the resulting solution was added in small portions of 15-20 ml to methyl alcohol (150 ml for 2-3 portions of polymer solution). The separated polymer was washed 3 times with methyl alcohol, the excess alcohol was squeezed out and dried for 24 hours at room temperature, and then at 70 ° C under the vacuum of a water-jet pump for 18-24 hours.

Example 3

Obtaining hypercrosslinked oligophenylmethylsiloxane

Analogously to example 1, using oligophenylmethylsiloxane (OFMS). Cross-agent bis (chloromethyl) diphenyl or para-xylylene dichloride (1.5 mol per mol of polymer unit).

Example 4

Preparation of hypercrosslinked poly-N-vinylcarbazole

Analogously to example 1, using poly-N-vinylcarbazole (PVC). Poly-N-vinylcarbazole was obtained by thermal polymerization of a monomer in sealed ampoules at 120 ° C for 4 days. Cross-agent bis (chloromethyl) diphenyl or para-xylylene dichloride (1.5 mol per mol of polymer unit).

Example 5

Obtaining hypercrosslinked polyacenaphthylene

Analogously to example 1, using polyacenaphthylene (PAN). Polyacenaphthylene was obtained by thermal polymerization of a monomer in sealed ampoules at 120 ° C for 4 days. Cross-agent bis (chloromethyl) diphenyl or para-xylylene dichloride (1.5 mol per mol of polymer unit).

Example 6

Obtaining hypercrosslinked poly-2-vinylnaphthalene

Analogously to example 1, using poly-2-vinylnaphthalene (PVN). Poly-2-vinylnaphthalene was obtained by thermal polymerization of the monomer in sealed ampoules at 80 ° C, then at 100 ° C for 3, 4 days, respectively. Cross-agent bis (chloromethyl) diphenyl or para-xylylene dichloride (1.5 mol per mol of polymer unit).

Analysis of the method for producing a polymer sorbent according to the present invention and the known technical solutions shows that there is no set of features that are identical to this method in terms of technical essence. Comparative analysis of the proposed solution with the prototype shows that the claimed solution differs from the prototype in the conditions for obtaining hypercrosslinked polymers and the type of initial polymers for their synthesis.

Thus, the present method meets the "novelty" condition of the invention.

The method of the present invention does not follow explicitly from the prior art. This allows us to conclude that this solution meets the condition "inventive step".

This solution ensures the achievement of the specified technical result, can be realized when using the obtained highly porous polymers as sorbents, for example, when cleaning polluted air and in other sorption technologies, providing the possibility of repeated reproduction. This allows us to conclude that the condition "industrial applicability" is satisfied.

Claims (5)

A method for producing low-density hypercrosslinked polymers by cross-linking polymer chains in polymer solutions in an organic solvent from the class of chloroalkanes with bifunctional cross-agents in the presence of a Friedel-Crafts catalyst, characterized in that to obtain monolithic samples of highly porous cross-linked polymers with low density: - use rigid-chain polymers of linear structure containing aromatic rings: poly-alpha-methylstyrene, oligophenylmethyl-siloxane, poly-2-vinylnaphthalene, poly-N-vinylcarbazole, polyacenaphthylene; - carry out the reaction of crosslinking polymer chains in polymer solutions with a concentration of 1-2 wt. %; - bis-chloromethyl derivatives of biphenyl or benzene are used as bifunctional cross-linking compounds in an amount of 1.5-2 mol per 1 mol of the repeating unit of the polymer; - the solvent is removed from polymer organic gels after synthesis by freeze drying from benzene and by supercritical drying from carbon dioxide.

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