Preparation method of a kind of end amine group six-membered alicyclic amide monomer and alternating copolymer alicyclic copolyamide

Abstract

The application belongs to the technical field of high polymer material synthesis, and discloses a kind of terminal amine group six-membered alicyclic amide monomer and preparation method, the chemical general formula of monomer is: the preparation method of monomer is simple and easy to operate, and raw material cost is low.The application also discloses a kind of alternating alicyclic copolymer polyamide and preparation method, the chemical general formula of copolymer polyamide is: its raw material is terminal amine group six-membered alicyclic amide monomer and dicarboxylic acid, the product structure is regular, not only has higher crystallinity and melting point, but also has higher heat resistance and excellent ultraviolet aging resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer material synthesis, and particularly relates to a kind of terminal amine group six-membered alicyclic amide monomer and preparation method of alternating copolymer alicyclic copolymer polyamide. BACKGROUND

[0002] Polyamide is a kind of multi-purpose engineering thermoplastics, due to its excellent processing performance, thermal properties and mechanical properties, is widely used in machinery, electronics and electrical, packaging and other fields. Alicyclic polyamide refers to the polymer containing at least one or more fatty ring (mainly six-membered ring) monomer in the polyamide backbone. The introduction of aliphatic ring can improve the rigidity of polyamide molecular chain, reduce the movement ability of molecular chain, thereby improving the melting point and mechanical properties of polyamide. In addition, alicyclic polyamide also has excellent anti-UV aging performance, these characteristics make it have wide development prospect in the application direction requiring high strength and thermal stability.

[0003] Copolymerization modification is a common method for changing the properties of existing polyamide varieties by copolymerization method. The copolymer product is usually a random copolymer, and the order structure of the molecular chain is destroyed, so the crystallinity is often reduced, resulting in relatively low melting point, high water absorption and poor dimensional stability. Compared with random copolymer polyamide, alternating copolymer polyamide has alternating sequence distribution, and the molecular chain arrangement is more regular, having higher melting point and better thermal stability. However, there is no report on alternating alicyclic copolymer polyamide. SUMMARY

[0004] The purpose of the present application is to provide a kind of terminal amine group six-membered alicyclic amide monomer and its preparation method, and to provide an alternating alicyclic copolymer polyamide containing the monomer and its preparation method is another purpose of the present application.

[0005] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is:

[0006] A kind of terminal amine group six-membered alicyclic amide monomer, its general structure is:

[0007]

[0008] In the formula, R1 is one of C2~C 14 alkyl and its derivatives, and R2 is a six-membered alicyclic structure unit.

[0009] The terminal amine group six-membered alicyclic amide monomer is prepared by ester aminolysis reaction of 1,4-cyclohexane diacid ester and aliphatic diamine monomer, wherein the molar ratio of 1,4-cyclohexane diacid ester and aliphatic diamine monomer is 1:4~8.

[0010] The preparation method of the terminal amine group six-membered alicyclic amide monomer comprises the following steps:

[0011] 1) 1,4-cyclohexane diacid ester and aliphatic diamine with a molar ratio of 1:4-8 are added into a reaction bottle with condensation reflux device, and reacted at 120-140℃ for 4-6h under nitrogen protection;

[0012] 2) The system is cooled, the reaction product is precipitated with xylene, filtered, washed with anhydrous ethanol, and dried to obtain an amine-terminated six-membered alicyclic amide monomer.

[0013] As further preferred of the application, in step 1), the 1,4-cyclohexane diacid ester is dimethyl 1,4-cyclohexanedicarboxylate or diethyl 1,4-cyclohexanedicarboxylate.

[0014] As further preferred of the application, in step 1), the aliphatic diamine is selected from one of ethylenediamine, butanediamine, pentanediamine, hexanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine and tetradecanediamine.

[0015] The application provides an alternating aliphatic copolyamide prepared from the amine-terminated six-membered alicyclic amide monomer and dicarboxylic acid, and the general structure is:

[0016]

[0017] In the formula, R1 is one of C3-C8 alkyl and derivatives thereof, R2 is a six-membered alicyclic structure unit, and R3 is one or more of C3-C8 alkyl, aryl and derivatives thereof. 18 18

[0018] The application also provides a preparation method of the alternating copolyamide, comprising the following steps:

[0019] S1: preparing an alternating polyamide salt from the amine-terminated six-membered alicyclic amide monomer and dicarboxylic acid as raw materials;

[0020] S2: adding the alternating polyamide salt into a reactor for polymerization, under the protection of inert atmosphere, the system is heated to a predetermined temperature at a heating rate of 1-5℃ / min, and then pressure holding polymerization is carried out at a pressure of 0.7-2.0 MPa in the kettle, and the pressure holding time is 0.5-4h; when R1 is one of C2-C8 alkyl and derivatives thereof, and R3 is one of C3-C8 alkyl and derivatives thereof, the predetermined temperature is 190-220℃; when R1 is one of C8-C12 alkyl and derivatives thereof, and R3 is one of C3-C8 alkyl and derivatives thereof, the predetermined temperature is 170-200℃; 10 14 10 18 ​​​​​​

[0021] S3: After the system is drained of steam for 0.5-2h, the system is heated to 200-240℃, and then vacuumized to a pressure of less than 100Pa in the kettle to perform negative pressure polymerization, the negative pressure is maintained for 2-5h, and then the temperature is lowered to discharge, thus obtaining the alternating aliphatic-cyclic copolyamide, and the temperature of the negative pressure polymerization is not lower than the temperature of the pressure maintaining polymerization, when R1 is one of C2-C8 alkyl and its derivatives, and R3 is one of C3-C8 alkyl and its derivatives, the preset temperature is 220-240℃, when R1 is one of C8-C12 alkyl and its derivatives, and R3 is one of C3-C8 alkyl and its derivatives, the preset temperature is 200-220℃, and when R1 is one of C8-C12 alkyl and its derivatives, and R3 is one of C3-C8 alkyl and its derivatives, the preset temperature is 200-220℃. 10 14 10 18

[0022] As a further preferred embodiment of the present application, the specific operation of S1 is as follows: the end-amine six-membered alicyclic amide monomer and the dicarboxylic acid monomer are respectively dissolved in an organic solvent, heated to dissolution by stirring and reflux, mixed, stirred, cooled to room temperature, filtered to remove the precipitate, washed with ethanol, and dried.

[0023] As a further preferred embodiment of the present application, in S1, the molar ratio of the end-amine six-membered alicyclic amide monomer to the dicarboxylic acid is 1:0.98-1.02.

[0024] As a further preferred embodiment of the present application, the organic solvent is DMF, NMP or DMSO, and the mass ratio of the end-amine six-membered alicyclic amide monomer and the dicarboxylic acid monomer to the organic solvent is 1:3-8.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] (1) The present application provides an end-amine six-membered alicyclic amide monomer and an alternating aliphatic-cyclic copolyamide, the regular structure of the alternating polyamide endows it with a high melting point and crystallinity, and the presence of the six-membered alicyclic structure improves the heat resistance and ultraviolet aging resistance of the material.

[0027] (2) In the preparation of the copolyamide, the present application controls the reaction temperature to be lower than the melting point of the polyamide salt and the final product, so that the material is always in a macroscopically solid state (without large-scale melting) during the entire reaction process, which not only ensures that the sequence structure of the polyamide molecular chain is alternating, but also improves the production efficiency and shortens the production cycle; the obtained product is in the form of white powder and can be used without granulation, compared with the traditional solution prepolymerization-solid phase post-polymerization process which has the disadvantages of long polymerization time, complex process and waste liquid generation, the method of the present application is more suitable for industrial promotion. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 ​​​​The infrared spectrum of the terminal amine hexacyclic cycloamide monomer prepared in Example 2;

[0029] Figure 2 The TG spectra of the alternating and random alicyclic copolyamides prepared in Example 7 and Comparative Example 1 are shown.

[0030] Figure 3 The following are the DSC spectra of the alternating and random alicyclic copolyamides prepared in Example 7 and Comparative Example 1;

[0031] Figure 4 The XRD patterns of the alternating and random alicyclic copolyamides prepared in Example 7 and Comparative Example 1 are shown below.

[0032] Figure 5 The specific viscosity diagram shows the alicyclic copolyamide and semi-aromatic copolyamide samples prepared in Example 7 and Comparative Example 3 at different UV aging times. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. It should be noted that these examples are provided to aid in understanding the invention and not to limit its scope. All raw materials used in the present invention are commercially available.

[0034] Example 1

[0035] This embodiment describes a terminal amine-terminated hexacyclic alicyclic amide monomer obtained by the ammonolysis reaction of methyl 1,4-cyclohexanedicarboxylate (200 g / mol) and pentanediamine (102 g / mol). Its chemical formula is:

[0036]

[0037] Its preparation method is as follows:

[0038] (1) Add 40g (0.2mol) of methyl 1,4-cyclohexanedicarboxylate and 81.6g (0.8mol) of pentanediamine to a reaction flask equipped with a reflux condenser, purge with nitrogen, heat in an oil bath to 120℃ and reflux for 4h until the reaction is complete.

[0039] (2) After the reaction is complete, the temperature is lowered to room temperature. The reaction product is precipitated with xylene, filtered, washed with anhydrous ethanol, filtered, and dried in a vacuum oven at 60°C for 24 hours to obtain a terminal amine hexacyclic cycloamide monomer.

[0040] Example 2

[0041] The end-amine six-membered alicyclic amide monomer of the present embodiment is obtained by ester aminolysis reaction of 1,4-cyclohexane dimethyl ester (200 g / mol) and hexanediamine (116 g / mol), and has the chemical formula of:

[0042]

[0043] The preparation method is:

[0044] 1) 40 g (0.2 mol) of 1,4-cyclohexane dimethyl ester and 92.8 g (0.8 mol) of hexanediamine are added into a reaction bottle with a condensation reflux device, nitrogen protection is performed, the oil bath is warmed to 120°C for reflux reaction for 6 h until the reaction is complete;

[0045] 2) After the reaction is complete, the reaction product is precipitated with xylene, filtered, washed with anhydrous ethanol, suction filtered, and dried in a vacuum oven at 60°C for 24 h to obtain the end-amine six-membered alicyclic amide monomer.

[0046] Example 3

[0047] The end-amine six-membered alicyclic amide monomer of the present embodiment is obtained by ester aminolysis reaction of 1,4-cyclohexane dimethyl ester (200 g / mol) and 1,10-diamino decane (172 g / mol), and has the chemical formula of:

[0048]

[0049] The preparation method is:

[0050] (1) 40 g (0.2 mol) of 1,4-cyclohexane dimethyl ester and 206.4 g (1.2 mol) of 1,10-diamino decane are added into a reaction bottle with a condensation reflux device, nitrogen protection is performed, the oil bath is warmed to 130°C for reflux reaction for 8 h until the reaction is complete;

[0051] (2) After the reaction is complete, the reaction product is precipitated with xylene, filtered, washed with anhydrous ethanol, suction filtered, and dried in a vacuum oven at 60°C for 24 h to obtain the end-amine six-membered alicyclic amide monomer.

[0052] Example 4

[0053] The end-amine six-membered alicyclic amide monomer of the present embodiment is obtained by ester aminolysis reaction of 1,4-cyclohexane dimethyl ester (200 g / mol) and 1,10-diamino decane (172 g / mol) and pentanediamine (102 g / mol), and has the chemical formula of:

[0054]

[0055] The preparation method is as follows:

[0056] (1) 40 g (0.2 mol) of 1,4-cyclohexane dimethyl ester and 223.2 g (1.2 mol) of 1,11-diamino-undecane were added into a reaction bottle with a condenser reflux device, and nitrogen protection was performed, and the oil bath was heated to 140 DEG C to reflux for 8 h until the reaction was complete;

[0057] (2) After the reaction was complete, the reaction product was precipitated with xylene, filtered, washed with anhydrous ethanol, suction filtered, and dried in a vacuum oven at 60 DEG C for 24 h to obtain the terminal amine group six-membered alicyclic amide monomer.

[0058] Example 5

[0059] An alternating alicyclic copolyamide alt-PA 5C / 54 of this example was obtained by polymerizing the terminal amine group six-membered alicyclic amide monomer obtained in Example 1 with succinic acid.

[0060] The preparation method is as follows:

[0061] S1: 3.4 g (0.01 mol) of the terminal amine group six-membered alicyclic amide monomer and 1.18 g (0.01 mol) of succinic acid were respectively dissolved in 10 g of NMP solvent, heated to 90 DEG C under stirring reflux, mixed, stirred for 30 min, and cooled to room temperature. The precipitate was filtered, washed with ethanol and dried to obtain the alternating PA 5C / 54 salt.

[0062] S2: 5 g of the alternating PA 5C / 54 salt was placed into a solid-phase polymerization kettle, sealed, and subjected to the operation of gassing-vacuumizing-gassing repeatedly for 3 times to replace the air in the reaction kettle and remove the oxygen in the system to ensure that the reaction was carried out in an inert gas atmosphere; the system was subjected to a temperature rising process at a temperature rising rate of 1 DEG C / min to 210 DEG C, and was kept at 210 DEG C for 1 h,

[0063] S3: The steam was discharged for 1 h, and the temperature was raised to 230 DEG C under vacuum to continue the reaction for 2 h. Subsequently, the temperature was lowered to discharge the product, and the alternating PA 5C / 54 was obtained.

[0064] Example 6

[0065] An alternating alicyclic copolyamide alt-PA 5C / 56 of this example was obtained by polymerizing the terminal amine group six-membered alicyclic amide monomer obtained in Example 1 with adipic acid.

[0066] The preparation method is as follows:

[0067] S1 : 3.4g (0.01 mol) of the terminal amine group six-membered alicyclic amide monomer and 1.46g (0.01 mol) of adipic acid were dissolved in 10g of NMP solvent respectively, heated to 90°C under stirring and reflux, mixed, stirred for 30min, and cooled to room temperature. The precipitate was filtered, washed with ethanol and dried to obtain the salt of the alternate PA 5C / 56;

[0068] S2: 4g of the salt of the alternate PA 5C / 56 was placed into a solid-phase polymerization kettle, sealed, and the air in the reaction kettle was replaced by repeating the operation of gassing-vacuumizing-gassing three times to remove oxygen in the system and ensure that the reaction was carried out in an inert gas atmosphere. The system started the temperature rising process, and was heated to 210°C at a rate of 1°C / min and kept at this temperature for 1h under pressure.

[0069] S3: The system was vented for 1h, and then heated to 230°C under vacuum for 2h of continuous reaction. Subsequently, the temperature was lowered and the product was discharged, thereby obtaining the alternate PA 5C / 56.

[0070] Example 7

[0071] An alternate alicyclic copolyamide alt-PA 6C / 66 was obtained by polymerization of the terminal amine group six-membered alicyclic amide monomer obtained in Example 2 and adipic acid.

[0072] The preparation method is as follows:

[0073] S1 : 3.68g (0.01 mol) of the terminal amine group six-membered alicyclic amide monomer and 1.46g (0.01 mol) of adipic acid were dissolved in 10g of DMF solvent respectively, heated to 90°C under stirring and reflux, mixed, stirred for 30min, and cooled to room temperature. The precipitate was filtered, washed with ethanol and dried to obtain the salt of the alternate PA 6C / 66;

[0074] S2: 4g of the salt of the alternate PA 6C / 66 was placed into a solid-phase polymerization kettle, sealed, and the air in the reaction kettle was replaced by repeating the operation of gassing-vacuumizing-gassing three times to remove oxygen in the system and ensure that the reaction was carried out in an inert gas atmosphere. The system started the temperature rising process, and was heated to 200°C at a rate of 1°C / min and kept at this temperature for 1h under pressure.

[0075] S3: The system was vented for 1h, and then heated to 220°C under vacuum for 4h of continuous reaction. Subsequently, the temperature was lowered and the product was discharged, thereby obtaining the alternate PA 6C / 66. The melting point thereof was 318°C, T5% (temperature at 5% weight loss) was 412°C, and the intrinsic viscosity was 0.97dL / g.

[0076] Example 8

[0077] An alternating aliphatic copolyamide alt-PA 6C / 611 is obtained by polymerization of the amine-terminated six-membered alicyclic amide monomer obtained in Example 2 and undecanedioic acid.

[0078] The preparation method is as follows:

[0079] S1: 3.68 g (0.01 mol) of the amine-terminated six-membered alicyclic amide monomer and 2.16 g (0.01 mol) of undecanedioic acid are separately dissolved in 10 g of DMF solvent, heated to 80°C under stirring and reflux, mixed, stirred for 30 min, and cooled to room temperature. The precipitate is filtered, washed with ethanol and dried to obtain the salt of alt-PA 6C / 611;

[0080] S2: 5 g of the salt of alt-PA 6C / 611 is placed into a solid-phase polymerization kettle, sealed, and subjected to the operation of gassing-vacuumizing-gassing repeatedly for 3 times to replace the air in the reaction kettle and remove oxygen in the system, so that the reaction is ensured to be carried out in an inert gas atmosphere; the system is subjected to a temperature rising process at a temperature rising rate of 1°C / min to 200°C, and is kept at 200°C for 1 h under pressure;

[0081] S3: steam is released for 1 h, and the temperature is raised to 220°C under vacuum for continuous reaction for 6 h. Then the temperature is lowered to discharge the product, and the alt-PA 6C / 611 is obtained.

[0082] Example 9

[0083] An alternating aliphatic copolyamide alt-PA 10C / 105 is obtained by polymerization of the amine-terminated six-membered alicyclic amide monomer obtained in Example 3 and undecanedioic acid.

[0084] The preparation method is as follows:

[0085] S1: 4.8 g (0.01 mol) of the amine-terminated six-membered alicyclic amide monomer and 1.32 g (0.01 mol) of glutaric acid are separately dissolved in 15 g of DMSO solvent, heated to 90°C under stirring and reflux, mixed, stirred for 30 min, and cooled to room temperature. The precipitate is filtered, washed with ethanol and dried to obtain the salt of alt-PA 10C105;

[0086] S2: 5 g of the salt of alt-PA 10C105 is placed into a solid-phase polymerization kettle, sealed, and subjected to the operation of gassing-vacuumizing-gassing repeatedly for 3 times to replace the air in the reaction kettle and remove oxygen in the system, so that the reaction is ensured to be carried out in an inert gas atmosphere; the system is subjected to a temperature rising process at a temperature rising rate of 1°C / min to 180°C, and is kept at 180°C for 1 h under pressure;

[0087] S3: steam is released for 1 h, and the temperature is raised to 210°C under vacuum for continuous reaction for 6 h. Then the temperature is lowered to discharge the product, and the alt-PA 10C / 105 is obtained.

[0088] Example 10

[0089] An alternating aliphatic copolyamide alt-PA 11C / 115, obtained by polymerization of the amino-terminated six-membered alicyclic amide monomer obtained in Example 4 and sebacic acid.

[0090] The preparation method is as follows:

[0091] S1: 5.24 g (0.01 mol) of the amino-terminated six-membered alicyclic amide monomer and 1.32 g (0.01 mol) of glutaric acid were separately dissolved in 15 g of DMSO solvent, heated to 80°C under stirring reflux, mixed, stirred for 30 min, and cooled to room temperature. The precipitate was filtered, washed with ethanol and dried to obtain the alternating PA 11C / 115 salt.

[0092] S2: 5 g of the alternating PA 5C / 510 salt was placed into a solid-phase polymerization kettle, sealed, and subjected to the operation of gassing-vacuumizing-gassing repeatedly for 3 times to replace the air in the reaction kettle and remove oxygen in the system, so as to ensure that the reaction was carried out in an inert gas atmosphere; the system was subjected to a temperature rising process at a temperature rising rate of 1°C / min to 180°C, and was kept at 180°C for 1 h.

[0093] S3: The steam was discharged for 1 h, and the temperature was raised to 210°C under vacuum to continue the reaction for 4 h. Subsequently, the temperature was lowered to discharge the product, and the alternating PA 11C / 115 was obtained.

[0094] Comparative Example 1

[0095] A random aliphatic copolyamide ran-PA 6C / 66, obtained by condensation polymerization of cyclohexanedicarboxylic acid, adipic acid and hexamethylenediamine.

[0096] The preparation method is as follows:

[0097] (1) 1.72 g (0.01 mol) of cyclohexanedicarboxylic acid, 1.46 g (0.01 mol) of adipic acid and 2.32 g (0.02 mol) of hexamethylenediamine were added into a three-necked flask equipped with a thermometer, and 20 g of distilled water was further added. The temperature was raised to 90°C, and the mixture was stirred magnetically for 30 min until a clear and transparent solution was obtained. The pH was adjusted to 7.0-7.5, and the stirring was continued for 20 min to make the reaction reach equilibrium. The water was evaporated by distillation under reduced pressure, and the product was dried in a vacuum oven to obtain a white powder of PA 6C / 66 salt.

[0098] (2) Put 5 g of PA 6C / 66 salt into a 500 mL reaction kettle, and add 5 g of distilled water to the reaction kettle. Seal the reaction kettle, and replace the air in the reaction kettle by repeating the operation of gassing-vacuumizing-gassing for 3 times to remove oxygen in the system, so as to ensure that the reaction is carried out in an inert gas atmosphere; heat to 200°C at a rate of 20°C / min, and keep the pressure for 1 h, vent for 1 h, and then heat to 230°C under vacuum to continue the reaction for 2 h, so as to obtain a random aliphatic polyamide PA 6C / 66, the intrinsic viscosity of which is 0.98 dL / g.

[0099] Comparative Example 2

[0100] An alternating aliphatic copolyamide alt-PA 10C / 106 is obtained by polymerizing the terminal amine-based six-membered alicyclic amide monomer obtained in Example 3 with adipic acid.

[0101] The preparation method is as follows:

[0102] (1) 4.8 g (0.01 mol) of terminal amine-based six-membered alicyclic amide monomer and 1.46 g (0.01 mol) of adipic acid are respectively dissolved in 15 g of DMSO solvent, heated to 90°C by stirring and reflux, mixed, stirred for 30 min, and cooled to room temperature. The precipitate is filtered, washed with ethanol and dried to obtain an alternating PA 10C / 106 salt;

[0103] (2) Put 5 g of the alternating PA 10C1066 salt into a solid-phase polymerization kettle, seal, and replace the air in the reaction kettle by repeating the operation of gassing-vacuumizing-gassing for 3 times to remove oxygen in the system, so as to ensure that the reaction is carried out in an inert gas atmosphere; start the heating process, and heat to 210°C at a rate of 1°C / min, keep the pressure for 1 h, and then heat to 220°C under vacuum to continue the reaction for 3 h. Then, cool and discharge, to obtain the alternating PA 10C / 106. The melting point thereof is 226°C, T5% (temperature at 5% weight loss) is 398°C, and the intrinsic viscosity is 1.02 dL / g.

[0104] (3) Vent for 1 h, heat to 220°C under vacuum to continue the reaction for 3 h. Then, cool and discharge, to obtain the alternating PA 10C / 106. The melting point thereof is 226°C, T5% (temperature at 5% weight loss) is 398°C, and the intrinsic viscosity is 1.02 dL / g.

[0105] Comparative Example 3

[0106] A random semi-aromatic copolyamide ran-PA 6T / 66 is obtained by condensation polymerization of terephthalic acid, adipic acid and hexamethylene diamine.

[0107] The preparation method is as follows:

[0108] (1) 1.66 g (0.01 mol) of terephthalic acid, 1.46 g (0.01 mol) of adipic acid, 2.32 g (0.02 mol) of hexamethylene diamine were added into a three-necked flask equipped with a thermometer, 20 g of distilled water was added, the temperature was raised to 80 °C, and magnetic stirring was carried out for 30 min until a clear transparent solution was obtained, the pH was adjusted to 7.0-7.5, and stirring was continued for 10 min until the reaction reached equilibrium, the water was distilled off under reduced pressure, and the product was dried in a vacuum oven to obtain PA 6T / 66 salt

[0109] 6T / 66 salt white powder.

[0110] (2) 5 g of PA 6T / 66 salt was placed in a 500 mL reaction kettle, and 5 g of distilled water was added into the reaction kettle. The reaction kettle was sealed, and the air in the reaction kettle was replaced by repeating the operation of gassing-vacuumizing-gassing for 3 times to remove oxygen in the system and ensure that the reaction was carried out in an inert gas atmosphere; the temperature was raised to 210 °C at a rate of 20 °C / min, and the temperature was kept for 1 h, the steam was discharged for 1 h, the temperature was raised to 240 °C under vacuum, and the reaction was continued for 3 h to obtain a random aliphatic polyamide PA 6T / 66.

[0111] Structural characterization and performance test

[0112] In order to show that the obtained product is the target product and the effect of the present application, the structural characterization and performance test of the prepared amine-terminated six-membered alicyclic amide monomer and the alternating and random aliphatic copolyamide were carried out by taking Example 2, Example 7, Comparative Example 1, Comparative Example 2 and Comparative Example 3 as examples, and the results are shown in Figures 1-5 .

[0113] Among them, Figure 1 the infrared spectrum of the amine-terminated six-membered alicyclic amide monomer prepared in Example 2, from the figure, it can be seen that: 3314 cm -1 is the N-H stretching vibration peak, 1649 cm -1 is the C=O stretching vibration peak, which is called amide I band, 1548 cm -1 is the amide II absorption band, and the infrared spectrum characteristics prove the successful synthesis of the amine-terminated six-membered alicyclic amide monomer.

[0114] Figure 2 TG spectrum of the alternating and random aliphatic copolyamides prepared in Example 7 and Comparative Example 1, Comparative Example 2, from the figure, it can be seen that the T 5％ (temperature at 5% weight loss) of the alternating PA 6C / 66 is 412 °C, the T 5％ (temperature at 5% weight loss) of the random PA 6C / 66 is 384 °C, the T 5％ (temperature at 5% weight loss) of the alternating PA 10C / 106 is 398 °C, and the T5％ Tg of the alternating PA 6C / 66 is 28℃ higher than that of the random PA 6C / 66, which further proves that the alternating aliphatic copolyamide has more excellent heat resistance. 5％ Tg of the alternating PA 6C / 66 is 28℃ higher than that of the random PA 6C / 66, which further proves that the alternating aliphatic copolyamide has more excellent heat resistance. 5％ Tg of the alternating PA 10C / 106 is 14℃ higher than that of the random PA 10C / 106, which proves that the alternating aliphatic copolyamide with shorter carbon chain has better heat resistance. 5％ Tg of the alternating PA 10C / 106 is 14℃ higher than that of the random PA 10C / 106, which proves that the alternating aliphatic copolyamide with shorter carbon chain has better heat resistance.

[0115] Figure 3 The DSC spectra of the alternating and random aliphatic copolyamides prepared in Example 7 and Comparative Example 1 and 2 are shown in the figure. The melting point of the alternating PA 6C / 66 is 318℃, and the melting point of the random PA 6C / 66 is 301℃. Due to the more regular sequence structure, the melting point of the alternating PA 6C / 66 is 17℃ higher than that of the random PA 6C / 66.

[0116] Figure 4 The XRD spectra of the alternating and random aliphatic copolyamides prepared in Example 7 and Comparative Example 1 are shown in the figure. The crystallinity of the alternating PA 6C / 66 is 63.76%, and the crystallinity of the random PA 6C / 66 is 58.29%. Due to the more regular sequence structure, the crystallinity of the alternating PA 6C / 66 is higher than that of the random PA 6C / 66.

[0117] Figure 5 The specific viscosity graphs of the alternating aliphatic copolyamide PA 6C / 66 prepared in Example 7 and the PA PT / 66 prepared in Comparative Example 3 with different UV aging time samples are shown in the figure. The intrinsic viscosity of the PA 6C / 66 changes less after UV aging, and the UV aging resistance is more excellent.

[0118] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and all shall be included in the protection scope of the present application.

Claims

1. Process for the preparation of an alternating aliphatic-cycloaliphatic copolyamide, characterized in that, The structural general formula of the alternating aliphatic copolyamide is: ，n>20； wherein R1is one of C2-C 14 alkyl, R2is a six-membered alicyclic structural unit, and R3is one or more of C3-C 18 alkyl. The preparation method comprises the following steps: S1: using an amine-terminated six-membered alicyclic amide monomer and a dicarboxylic acid as raw materials to prepare an alternating polyamide salt; The structural general formula of the amine-terminated six-membered alicyclic amide monomer is: wherein R1is one of C2-C 14 alkyl, and R2is a six-membered alicyclic structural unit; S2: polymerizing the alternating polyamide salt in a reactor, under the protection of an inert atmosphere, the system is heated to a predetermined temperature at a heating rate of 1-5 ℃ / min, pressure maintaining polymerization is carried out under a kettle pressure of 0.7-2.0 MPa, and the pressure maintaining time is 0.5-4 h; S3: then the system is drained of steam for 0.5-2 h to reduce the pressure to normal pressure, the system is continuously heated to a certain temperature, vacuum polymerization is carried out by vacuumizing the system to a kettle pressure of less than 100 Pa, the negative pressure is maintained for 2-5 h, and then the system is cooled and discharged, thereby obtaining the alternating aliphatic copolyamide, and the temperature of the vacuum polymerization is not lower than the temperature of the pressure maintaining polymerization.

2. Process for the preparation of an alternating aliphatic-cycloaliphatic copolyamide according to claim 1, characterized in that: The specific operation of S1 is as follows: the amine-terminated six-membered alicyclic amide monomer and the dicarboxylic acid monomer are respectively dissolved in an organic solvent, heated to dissolution under stirring and reflux, mixed, stirred, cooled to room temperature, filtered to remove the precipitate, washed with ethanol, and dried.

3. Process for the preparation of an alternating aliphatic-cycloaliphatic copolyamide according to claim 2, characterized in that: In S1, the molar ratio of the amine-terminated six-membered alicyclic amide monomer to the dicarboxylic acid is 1:0.98-1.

02.

4. Process for the preparation of an alternating aliphatic-cycloaliphatic copolyamide according to claim 2, characterized in that: The organic solvent is DMF, NMP or DMSO, and the mass ratio of the amine-terminated six-membered alicyclic amide monomer and the dicarboxylic acid monomer raw materials to the organic solvent is 1:3-8.

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