RU2245345C1 - Aromatic polyamide production process - Google Patents

Abstract

FIELD: polymer production.

SUBSTANCE: invention relates to polyamides that can be used in a variety of arias as high-strength and high-temperature-resistant coatings, plastic binders, glass plastics, and films. Two-stage production process comprises preparation of polyimidates via non-equilibrium polycondensation of bis-phenols with N-phenylimine chloride based on mono- and dicarboxylic acids, after which resulting polyimidates are subjected to Chapman rearrangement at 240-260^оС for 5-6 h.

EFFECT: enabled production of polymers showing good solubility and elevated treatment resistance.

2 tbl, 12 ex

Description

The invention relates to the chemistry of macromolecular compounds, in particular, to a method for producing heat-resistant polyheteroarylenes, which can be used in the industry of polymer products, in particular binders for plastics and fiberglass, as well as adhesives, coatings and film materials.

Known (US Pat. USA No. 3418275, publ. 1968, US Pat. No. 3624033, publ. 1971, Fedotova O.Ya. et al. High-molecular. Compound. - 1960. - T.2. - p. 899 -903., Hesegawa H. Bull. Chem. Soc. Japan. - 1954. - V.27. - p.227-235.) Classical methods for producing aromatic polyamides (APA) by low-temperature polycondensation of diamines with dicarboxylic acids or their derivatives and homopolycondensation aromatic amino acids or their derivatives in solution, in the melt and at the phase boundary. These methods lead to polymers with limited solubility, insufficient heat resistance and a small interval between softening and decomposition temperatures and, as a result, lead to poor processing ability of polymers of this type.

It is impossible to isolate the closest analogue of the present invention, because existing methods, and some of them are described in the reactions of polycondensation or polymerization of monomer or monomers, and the proposed method consists in rearrangement of the previously obtained polyimidate unit.

The technical result of the invention is to increase heat resistance, improve physical and mechanical characteristics and provide the possibility of processing PA into products using modern industrial methods.

To achieve a technical result, it is proposed to obtain N-phenyl-substituted aromatic PAs by the reaction of intramolecular thermal rearrangement of polyimidates (polyimideoesters) by Chapman rearrangement [Vatsuro K.V., Mishchenko G.L. // Named reactions in organic chemistry. M .: Chemistry, 1976, 471 p .; Chapman A.W. // J. Chem. Soc. 1925. V.127. P.1992]. Polyimidates are obtained by nonequilibrium polycondensation of bis-phenols with a slight excess of N-phenylimino chloride based on mono- and dicarboxylic acids (molar ratio of bis-phenol to N-phenylimino chloride 1,000: 1,080-1,120) of the following structure:

The reactions are carried out as follows:

Coefficients m and n are the number of moles of monomers that have entered into the polycondensation reaction. The ratio m / (n-m) and the coefficient p are the degree of polymerization lying in the regions 43-50 and 38-46, respectively.

The nonequilibrium polycondensation reaction in a solution of N-methyl-2-pyrrolidone (N-MP) bis-phenol with N-phenyliminochloride is carried out as follows.

Into a solution (N-MP) of bis-phenol and triethylamine with stirring at 20 ° C in small portions for 15-20 minutes. a solution of (N-MP) N-phenyliminochloride is introduced. After homogenization, the reaction mixture is placed in a metal bath while blowing argon. Polycondensation is carried out for 15-16 hours at 150-160 ° C, depending on the structure of the starting monomers with the formation of polyimidates, yield 94-97%.

The rearrangement was carried out at 240-260 ° C for 5-6 hours, while there was a slight decrease in the molecular weight of the resulting polyamide. The polymers are completely soluble in concentrated sulfuric and formic acids, amide solvents. The reaction conditions and properties of the obtained aromatic PA are shown in table 1.

The structure of the obtained aromatic PA is confirmed by the data of IR spectroscopy, C ¹³ and H ¹ NMR spectroscopy. So, according to IR spectroscopy, the characteristic absorption bands from the region of 1665-1635 cm ^-1 (C = N) are shifted to the region of 1690-1660 cm ^-1 (C = O), and the bands in the region of 1280-1260 cm ^{-1 are} imidoester ( С-О) communications are practically absent.

According to dynamic thermogravimetric analysis (5 deg / min, in air), polyamides lose 10% of their initial weight at 410-460 ° C (see Table 1).

Pressing of powders of aromatic polyamides at a pressure of 70-75 MPa and 250-350 ° C obtained press materials whose properties are shown in Table 2.

The proposed method is confirmed by the following examples. All examples are shown with a slight excess of N-phenyliminochloride.

Example 1. To a solution of (N-MP) bis-phenol (0.01 mol) in a three-necked flask equipped with a stirrer, an argon inlet and a dropping funnel, with vigorous stirring in the presence of triethylamine (0.022 mol) for 15-20 minutes. a solution of (N-MP) N-phenylimino chloride based on dicarboxylic acids (0.011 mol) was added at 20 ° C. The homogenized reaction mixture was immersed in a bath while feeding argon at a rate of 10-30 ml / min. The synthesis was carried out for 15-16 hours at 150-160 ° C. The product was planted in a 2% aqueous ammonia solution, separated on a filter, washed successively with a 1% sodium bisulfite solution and water. Dried in a vacuum oven at 60-70 ° C to constant weight.

The rearrangement of polyimidates in PA was carried out in a condensation tube at 240–260 ° С for 5–6 hours with argon purging at a rate of 10–30 ml / min. The yield of PA is quantitative.

Example 2. To a solution (N-MP) of resorcinol 1.1000 g (0.0100 mol) in a three-necked flask equipped with a stirrer, an argon inlet and a dropping funnel, with vigorous stirring in the presence of triethylamine 2.2220 g (0.0220 mol ) within 15-20 minutes a solution of (N-MP) N, N’-diphenylisophthaliminochloride 3.8830 g (0.0110 mol) was added at 20 ° C. The homogenized reaction mixture was immersed in a bath while feeding argon at a rate of 10-30 ml / min. The synthesis was carried out for 15-16 hours at 150-160 ° C. The product was planted in a 2% aqueous ammonia solution, separated on a filter, washed successively with a 1% sodium bisulfite solution and water. Dried in a vacuum oven at 60-70 ° C to constant weight.

The rearrangement of polyimidates in PA was carried out analogously to example 1.

Example 3. Non-equilibrium polyheterocondensation between bis-phenols and N-phenyliminochlorides based on monocarboxylic acids, namely the polycondensation of 1.1000 g (0.0100 mol) of hydroquinone and 4.8060 g (0.0108 mol), 4.4'-ox -bis- (N-phenylenebenziminochloride) in the presence of triethylamine 2.1816 g (0.0216 mol) and subsequent rearrangement in PA was carried out analogously to example 1.

The loading of polyimidates for rearrangement in PA in all examples was 0.005 mol, the degree of rearrangement was 74.5-88.7%.

table 2
Physico-mechanical properties of press materials based on the obtained PA. n / a PA Specific impact strength, kgf cm / cm ² GOST 4647-80 Tensile stress, MPa GOST 4648-71 R ’or R’ ’ R 1. 1a 2a 7.5-8.5 600 2. 1a 2c 6.5-7.5 580 3. 1b 2a 6.5-7.0 590 4. 1b 2b 6.0-6.5 570 5. 1.1a 2a 8.0-8.5 600 6. 1.1a 2c 7.0-7.5 590 7. 1.1b 2b 7.0-7.5 620 8. 1.1b 2c 7.0-7.5 630

As can be seen from the data of Tables 1, 2, the proposed method for producing aromatic PAs compares favorably with the fact that polymers are obtained with high values of viscosity properties, relatively good solubility and good processability into polymeric materials by modern methods, as well as high values of the physicomechanical properties of their materials and high resistance to thermal oxidative degradation.

Table 1
Production conditions and properties of aromatic PA n / a PA Gross formula of e-link M.M. e / link g / mol η pref. (DMF) dl / g ¹ Terms of receipt T the beginning of decomposition, ° C ² T the beginning of softening, ° C ³ R ’or R’ ’ R T, ° C Duration, hour 1. 1a 2a C ₂₆ H ₁₈ O ₂ N ₂ 390 0.67 240 5 430 320 2. 2b 0.68 240 5 420 315 3. 2s C ₃₂ H ₂₂ O ₄ N ₂ S 530 0.70 260 5 450 280 4. 1b 2a C ₂₆ H ₁₈ O ₂ N ₂ 390 0.65 250 6 420 300 5. 2b 0.71 250 6 410 295 6. 2s C ₃₂ H ₂₂ O ₄ N ₂ S 530 0.68 260 5 430 310 7. 1.1a 2a C ₃₃ H ₂₄ O ₂ N ₂ 480 0.60 250 6 440 300 8. 2b 0.64 250 6 430 290 9. 2s C ₃₉ H ₂₈ O ₄ N ₂ S 620 0.66 260 5 455 290 10. 1.1b 2a C ₃₂ H ₂₂ O ₃ N ₂ 482 0.64 250 6 440 270 eleven. 2b 0.69 250 6 430 280 12. 2s C ₃₈ H ₂₆ O ₅ N ₂ S 632 0.67 260 5 460 270 Notes: 1 - measurements were carried out at 20 ° С, s = 0.5 g / dl. 2 - temperature corresponding to 10% weight loss. 3 - temperature corresponding to 5% deformation.

The above complex of practically useful properties of the aromatic PA obtained determines the positive effect of the invention. The resulting aromatic PA can be used in various fields of technology as high-strength and high-temperature-resistant coatings, binders for plastics, fiberglass, films and adhesives.

Claims (1)

A method for producing aromatic polyamides, including nonequilibrium polycondensation of bis-phenols with N-phenylimine chloride based on mono- and dicarboxylic acids to obtain polyimidates and their subsequent rearrangement of Chapman at a temperature of 240-260 ° C for 5-6 hours