SU735606A1 - Method of preparing polyphenylquinoxalines - Google Patents

Description

The invention relates to methods for producing heat-resistant polymers that can be used for the production of press powders, coatings and adhesives, as well as connecting to the production of a wide variety of composite materials and is intended to increase the heat-resistance of polyphenylquinoxalines. The known polyphenylquinoxalines are promising high-temperature resistant polymers, however they have relatively low heat resistance. For example, the deformational heat resistance of poly-2,2- (1,4-phenylene) -7,7-oxyb- (3-phenylquinoxaline) is equal to 280 ° C, while the temperature of the onset of decomposition in air is 500 ° C. Methods are known for improving the heat resistance of polychinoxalines by forming cross-links that crosslink linear regions of polymer molecules. Polycondensation of bis (o-diamines) with poly-a-dicarbonyl compounds of various chemical structure 1 is used to obtain polychinoxines. The use of these structures leads to the formation of structured pykinoquinas, characterized by high heat-resistant {) sty. However, the polymers obtained have a rather low heat resistance and for a more complete implementation of the crosslinked structure they require long-term heat treatment (U) and high temperatures of 0 ° C and higher) or the formation of cross-links during the structuring of polychinoxaline etuce leads to the release of water, which leads to porosity of products from them. A method for the synthesis of polyamidoquinoxalines is described, which scatters them splushka with the participation of ester and carboxyl groups contained in the polymer structure and the secondary amino groups in amide groups 2. However, the presence of ester, carboxyl and amidium groups significantly reduces the thermal and thermal-oxidative stability of the linear patterns. By curing polyphenylquinoxalines containing ido-alicyclic groups 13}, polymers with a high heat resistance are obtained. This has a substantial advantage over other methods, since during the curing of the polymers in this 373 Shukoyo, the Molecule products are low molecular weight, leading to re-formation of thicknesses in the finished products. However, the products obtained by the Yaypimer could not be operated for a long time at temperatures above 280 ° C due to the low thermal stability of cyclic groups. - - - - -. . A known method for producing polyphenylquinoxalines containing hidden crosslinking groups, polycondensation aromatic bis- (o: -diamines) with bis- (odicarbonyl) compounds containing, as -substitutes, crosslinking groups, npfimer, p, p-oxybis- (p- cyanrbesil):

This method eliminates the thermoplasticity; n | iHBbicoKHX temperatures inherent in linear polyphenylchroxalines. In this case, better heat resistance can be achieved by taking advantage of inter1 and intramolecular cross-linking groups, such as -CN or -OCN, 1-of-the-line TepMoo6pa6otke obtained linear polymers 4. synOnCeLinGoSdDkd without isolation of any volatile products.

However, when synthesizing linear poly 6xPa polyfiles, it is necessary to be especially careful and cautious, because the knb has previously been weakly CIEM1Va1 and branched out of polymers, as a result of which Jero their solutions become preliminarily thick and unsuitable for processing. The danger of premature gelation; it is possible to LOWER if less pure substances are used in the reaction, or crush the stoichiometric ratio of monomers. However, in this case, the mechanical properties and thermal oxidative stability of the polymers deteriorate. A higher concentration of crosslinking groups eliminates their complete conversion during curing due to the rapid growth of steric and diffusion difficulties after the very first acts of interaction of these groups, which leads to the defectiveness of the polymer Mesh and the contraction of the polymer at elevated temperatures. polyphenylhynoxaline has to be carried out

heat treatment at extremely high temperatures (up to 450 ° C) in an inert atmosphere. In addition, polymers synthesized based on cyan-containing tetraketones have a higher softening temperature than a} similar polymers that do not contain nitrile groups, and therefore require higher processing temperatures. Thus, the need to use special monomers, the complexity of polymer synthesis and the need to form articles at very high temperatures limit the widespread use of the polymers obtained.

The purpose of the Invention is to obtain polyfeschquinoxalines capable of forming stable highly concentrated solutions, process at temperatures below 300 ° C with the formation of large-sized materials of increased heat resistance and resistance to solvent action.

To achieve this goal, polycondensation of bis- (o-diamines) with bis- (adiketones) is proposed to be carried out at a temperature of 20200 ° C for 0.5-5 hours with the formation of polymers having o-Dynamic end groups, after a quick polymer solution is added A compound selected from the group containing 4-cyaobenzyl, 4-cyanatobenzyl, 4-ethylbenzyl and the process is conducted at a temperature of 20-150 ° C for 0.5-3 hours.

Synthesized 1-polyphenylquoxal ins have the general formula

where X is -0-, -CHj-,) - O, SOj; Ar - m- or p-phenylene, or a group

R is -CN; OCN, -C CH;

n - from O to 100 (preferably from 1 to 50).

Synthesis of polymers is carried out in phenol type solvents or in mixtures of chlorinated hydrocarbons from alcohols, acids, or phenols. At the same time on the p moles of bis- (O-dicarbonyl x) compounds take (n + 1) mol of aromatic bis- (o-diamines). The resulting polyphenylquinoxalines with single terminal groups are treated with 5 7 0 -carboxylic compounds and precipitated into acetone, lower alcohols or used as varnishes to prepare prepregs. The resulting curing of the obtained polymers with terminal active groups was carried out in the presence or absence of catalysts when heated in an inert atmosphere. As bis (o-diamines), from the dinene of the formula Yng is used where X is as indicated above, tetraketones of the structure are used as bis (a-dicarbonyl) compounds where Ar is as described above. The blocking of the terminal o-diamine groups of polyphenylquinoxalines is carried out with 4-cyanobenzyl, 4-cyanatobenzyl or 4-ethylobenzyl. ; in an amount equivalent to the number of o-diamine groups. Example 1. To a flask equipped with a mechanical stirrer and an inertia gas inlet, 2.533 g (0.011 mol) of 3.3 -4.4-tetraamino-diphenkene ether are charged, 25 ml of m-cresol are added and 3.423 g are added ( 0.010 mol) 1,4-bis- (phenylglyoxalyl) benzene. Stirring is continued in an inert atmosphere for 1 hour and 0.483 g (0.002 mol) of 4-cyanobenzyl is added. After stirring for an hour, the resulting clear solution was poured into ethanol. The polymer is filtered off, dried, dissolved in chloroform and reprecipitated in ethanol. The viscosity of a 0.57% polymer solution in m-cresol at 25 ° C is 0.24 dp / g. The softening point of this polymer under a load of 5 kg / cm ccx; pressure 245 ° C. 1 g of powdered polymer is mixed with 0.03 g of zinc chloride, and the tablet is pressed at a temperature of 240-250 ° C. And the specific pressure of 50 kg / cm and, placing the molded tablet in a heating cabinet, kept it 5 "shs at 250 ° C and 10 hours at 300 ° C. The crosslinked shlifenilx noxalin does not soften to its decomposition temperature (500 ° C), although it exhibits a slight deformation under a load of 5 kg / cm at. The polymer does not dissolve in all approved solvents, including concentrated sulfuric acid. Example 2. In a flask containing a mixture of 200 ml of chloroform and 20 ml of ethyl alcohol, 24.16 g (0.105 mol) of 33.4,4-tetraamino-phenophenyl ether are stirred in and then, in several doses, 34.23 g (0.100 mol) 1 , 4-bis- (festglioksalil) benzopa. Stirring is continued for 2 hours and 2.41 g (0.01025 mol) of 4-cyanobenzip is added to the reaction solution. After stirring for 2 hours, popiphenylquinoxaline is formed with terminal nil soils, having a viscosity of 0.5% -1 of its solution in m-crepop at 25 ° C 0.4 dl / g. After saturating the glass brand. T10 / 1 with the reaction solution, feeding it for an hour, gradually raise the temperature to. The irradiated prepreg is collected in a bag and pressed at 280 ° C and a specific pressure of 10 kg / cm. Molded fiberglass after heat treatment at 300 ° C for 18 hours has a breaking stress during static bending 3900 kgf / cm Example 3. In a flask similar to example 1, 25 ml of m-cresol are loaded, g (0.011 mol) GF-diaminobenzidine and 3.423 g (0.01 mol) 1,4-bis (phenipglyoxalyl) benzole. After stirring for 2 hours, 0.483 g (0.00205 mol) of 4-cyanobenzyl was added to the reaction solution. Further, the reaction was carried out and the polymer was isolated as in Example 1. The reduced viscosity of a 0.5% polymer solution in m- cresol at 25 ° C. 0.22 dl / g, temp. 228 ° C. After heat treatment of the polymer with 5% zinc chloride in an inert atmosphere for 4 hours at 240 ° C, 4 hours at 260 ° C and 10 hours at 300 ° C, it does not soften to a temperature of 400 ° C. Example 4. In a flask as in Example 1, 25 ml of m-cresol are placed and a mixture of 3.635 g (0.015 mol) 33 of 4,4-tetraaminobenzophenone, 5.477 g (0.016 mol) of 1,4-bis (phenylgioxalyl) benzene and after stirring for 2 hours, load 0.483 g (0.002 mol) of 4-cyanobenzyl. Stirring is continued for 2 hours at room temperature, and then for 1 hour at 80 ° C. The formed clear red-brown viscous solution 773 is poured into ethyl alcohol. The precipitated polymer is filtered off, dried, dissolved in chloroform, and reprecipitated in ethanol. 1 g of the powdered polymer is moistened with 2 ml of iO-Horo alcohol solution of benzenesulfonic acid, triturated and dried. After heat treatment in an inert atmosphere at 280-300 ° C for 20 hours, the polymer does not dissolve in all tested solvents and does not soften to 400 ° C. Example 5. In a flask as in Example 1, 25 ml of m-cresol, 2357 g (0.011 mol) of ZZ-Diaminobenzidine and 3.423 g (0.01 mol) of 1,4-bis (phenylglyrxalyl) benzene will be placed. Stirring is continued for 2 hours and 0.468 g (0.002 mol) of 4-ethynylbenzene 1 is added to the acid solution. After stirring the reaction solution for 2 hours at room temperature and 0.5 hours at 100-120 ° C, the polymer was isolated as in Example I-; L, Heat treatment of the polymer in an inert atmosphere at 300-400 ° C for 12 hours leads to the formation of a material that does not soften under a load of 5 kg / cm D6 temperature of 400 ° C. The reaction solution of the polymer is used as an adhesive. Example 6, In a flask analogously to Example 1, 2.416 g (OD) 105 mol) 3.3, 4,4-tetraaminodiphenic ether, 25 ml of mcresol, 3.423 g (0.01 mol) 1,4-bis- (feschglyoxapyl) | 5 benzene and, after stirring for an hour, 0.251 g (0.001 mol) of 4-cyanatobenzyl. The reaction is carried out and the polymer is isolated as in Example I. The resulting polymer, containing terminal cyanate groups, is marked at 285 ° C. After heat treatment of the polymer containing 1% zinc chloride, at 300 ° C for 6 hours, a material that does not soften to 400 ° C is obtained. Insignificant deformation under a load of 5 kg / cm was observed at 370 ° C. The proposed method has several advantages over the method. Thus, for the synthesis of the main chain of popish shhinoksalins, the proposed method does not require special starting compounds, and the consumption of "dicarbonyl compounds" is small and amounts to 4-7% of in optimal cases. initial monomer weights. Polycondensation of conventional aromatic tetraamines with aromatic bis (and diketones) takes place at room temperature in available organic solvents for 2-4 hours with a quantitative yield. The reaction solutions are stable and stored for a long time. The use of a given excess of tetraamine makes it possible to obtain molecules of linear polyphenshthinoxalines of the required length, further determining the length of linear portions between the nodes of the polymer network, and, as a consequence, their thermomechanical and physical properties. The proposed method makes it possible to synthesize polyphenylquinoxalines with active end groups and mol. at. up to 50000 (preferably 5000-25000, BH3kocTb 0.5% solution in m-cresol at 25 ° C 0.20, 6 dl / g). The low melting point of such polymers allows them to be processed into products at temperatures lower than the processing temperatures of conventional linear polyphenylquinoxalines. Further trimerization of the active end groups during the heat treatment of the molded product allows to obtain cross-linked polyphenylquinoxalines that do not melt to the temperature of their decomposition. This process is not accompanied by the release of volatile products and is carried out at 250,350 ° C, with or without catalysts. Proton acids, Lewis acids, organic amines, organometallic and complex compounds of cobalt, iron, nickel, titanium, aluminum, zinc, tin, etc. can be used as a trimerization catalyst. In the manufacture of laminated plastics, the impregnation of reinforcing materials is usually carried out with solutions of polyphenylquinoxalines of 8-12% concentration, since the more concentrated solutions have a very high viscosity. Repeated impregnation is required to achieve the desired binder pump. The use of polyphenylquinoxalines with terminal nitrile, ciamate and ethylene groups synthesized according to the proposed method for the manufacture of laminated plastics allows increasing the concentration of the impregnating solution up to 50-60%, improving the quality of the wrinkle of fillers and improving the production technology of finished products. Thus, the hydroflame method results in the production of goliphenylquinoxalines, processed u) and temperatures lower (less than 300 ° C) than the processing temperatures of the known analogues (40d ° C and higher) and thermal treatment under relatively mild conditions (250-350 ° C compared with 400,450 ° C for limestone polyphenylchioxalines) forming materials of increased heat resistance and resistance to solvents. This iqjouecc passes without isolating volatile products and results in products that can work for a long time in very harsh temperature conditions. The polymers synthesized by the proposed method are dissolved in the available organic solvents to form highly concentrated solutions that provide high-quality impregnation of fillers and simplify the manufacturing technology of composite materials.

Claims (4)

Invention Formula A method of producing polyphenylsnoxalines by polycondensation of aromatic bis (o-diamines) with bis- (a-diketones), followed by heat treatment, characterized in that, with the aim of creating polyphenylshnnoxalines, capable of forming stable, high-oxidized solutions and working at temperatures below. 300 ° C with the formation in heat treatment of polymer materials of increased heat-resistance and resistance to the action of solvents, polycondensation of conductor gas at temperature 20–200 ° C for 0.5–5 h with the formation of polymers having o-diaxon end groups, and then a compound selected from the group containing 4-cyanobuenyl, 4-cyanatobenzyl, 4-ethylbenzyl and the process carried out at a temperature of 20ISO C for 0.5-3 hours. Sources of information taken into account in the examination Patent of the USA No. 3509097, cl. publish 1970. 2. Pateit USA N 3804807, cl. 260-65, publ. 1974. 3. US patent N 3905941, cl. 260-47, og tblik. 1975. 4. Pagit USA N 3852243, cl. 260-50, published. 1974 (prototype).