Preparation method of semi-aromatic polyamide-based composite material

Abstract

The invention relates to a preparation method of a semi-aromatic polyamide-based composite material, and belongs to the technical field of materials, PA6Z resin is subjected to vacuum drying and then uniformly mixed with a reinforcement material, and the composite material is obtained through extrusion and pelletizing in sequence; the PA6Z resin is prepared by mixing hexamethylenediamine, terephthalic acid and PA6Q salt and then sequentially carrying out pre-polymerization and polycondensation reactions, and the PA6Q salt is obtained by taking a 6Q monomer and terephthalic acid as raw materials and carrying out a reaction. The preparation method of the semi-aromatic polyamide-based composite material is simple in preparation, the mechanical property and heat resistance of the composite material are improved by designing the molecular structure of the PA6Z resin matrix, the process is controllable, and the product performance is stable.

Description

Technical Field

[0001] The invention belongs to the technical field of materials and relates to a method for preparing a semi-aromatic polyamide-based composite material. Background Art

[0002] Semi-aromatic polyamides (such as PA6T, PA9T, and PA10T) are a class of high-performance materials whose backbones contain both aromatic and aliphatic segments. Due to the synergistic effect of the rigid aromatic rings and flexible aliphatic chains within their molecular chains, these materials possess excellent heat resistance, mechanical strength, and dimensional stability, making them widely used in electronic packaging, automotive lightweighting, aerospace, and other fields.

[0003] To further improve performance, semi-aromatic polyamides are often used as the matrix of composite materials and reinforced by reinforcing materials (such as glass fiber, carbon fiber) or nanofillers (such as carbon nanotubes, graphene) to obtain higher strength, modulus and thermal stability.

[0004] However, at present, this type of composite material still has the following problems:

[0005] ① Heat resistance needs to be improved - Under high-temperature use environment, the material is prone to degradation of the resin matrix or damage to the reinforcement fibers, resulting in deterioration of mechanical properties, especially unmodified composite materials tend to become brittle after long-term heat exposure.

[0006] ② Low impact resistance - The rigid aromatic structure limits the plastic deformation ability of the molecular chain, making it difficult for the composite material to dissipate energy through yielding or microcracks under dynamic loads (such as impact and vibration), resulting in low-toughness fracture and poor impact resistance, making the composite material prone to brittle fracture under dynamic loads.

[0007] Reference 1 (Preparation and Performance Study of Chopped Glass Fiber Reinforced Nylon 12T Composites [D]. 2018.) discloses that dried high-temperature resistant polyamide resin, flame retardant, and glass fiber are melt-blended through a twin-screw extruder to obtain a composite material with good flame retardancy and physical and mechanical properties, but its impact resistance is not high.

[0008] Reference 2 (Effect of glass fiber content on the properties of PA10T / 1010 composites [J]. Engineering Plastics Applications, 2018, 46(2):31) prepared PA10T / GF / PTFE composites by blending high-temperature resistant PA10T, solid lubricant polytetrafluoroethylene (PTFE), and reinforcing material glass fiber. The wear resistance of the composite was improved, but the physical and mechanical properties of the matrix resin were reduced.

[0009] Reference 3 (Preparation and performance study of carbon fiber reinforced nylon PA6T / 66 copolymer composites [J]. Plastics Industry, 2015, 43(4): 124.) A carbon fiber (CF) and nylon copolymer (PA6T / 66) composite material was prepared by melt blending in a twin-screw extruder. The tensile strength and flexural strength of the composite material were improved to a certain extent, but the operation was complicated, and the initial decomposition temperature, melting point, and impact resistance of the composite material were not improved.

[0010] Therefore, it is of great significance to study a preparation method of a semi-aromatic polyamide-based composite material to solve the above problems. Summary of the Invention

[0011] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing a semi-aromatic polyamide-based composite material.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0013] A method for preparing a semi-aromatic polyamide-based composite material comprises vacuum drying PA6Z resin, uniformly mixing it with a reinforcement material, and sequentially extruding and pelletizing to obtain the composite material.

[0014] The chemical structure of PA6Z resin is as follows:

[0015] ;

[0016] Where x>0, y>0, x+y=1, and 40≤n≤500. If n is too small, the degree of polymerization is too low, resulting in low relative viscosity and melt strength. This can easily cause melt fracture or sag during extrusion, blow molding, and other processes, making molding difficult and limiting processability. If n is too large, the degree of polymerization is too high, making it difficult for the polymer chains to fully melt and homogenize during screw extrusion, potentially leading to uneven plasticization. If the polymer chains are too long, the melt viscosity increases sharply and fluidity decreases.

[0017] As the preferred technical solution:

[0018] In the above-mentioned method for preparing a semi-aromatic polyamide-based composite material, the vacuum drying temperature is 70-80° C. and the time is 24-72 hours.

[0019] In the above-mentioned method for preparing a semi-aromatic polyamide-based composite material, the reinforcement material is glass fiber or carbon fiber.

[0020] In the above-mentioned method for preparing a semi-aromatic polyamide-based composite material, the extrusion temperature is 290-310° C., and the extrusion rate is 30-50 r / min.

[0021] In the above-mentioned method for preparing a semi-aromatic polyamide-based composite material, the mass ratio of the vacuum-dried PA6Z resin to the reinforcement material is 1:0.05~1.

[0022] The preparation method of the semi-aromatic polyamide-based composite material as described above, wherein the semi-aromatic polyamide-based composite material has a melt index of 20-38 g / 10 min, an initial degradation temperature of 470-490° C., a heat deformation temperature of 290-340° C., a tensile strength of 100-250 MPa, an elongation at break of 3.1%-3.9%, a flexural strength of 140-280 MPa, a flexural modulus of 5800-16800 MPa, and an impact strength of 6.9-8.9 KJ / m 2 .

[0023] The preparation method of the semi-aromatic polyamide-based composite material is as described above. The preparation method of PA6Z resin is as follows: first, 6Q monomer and terephthalic acid are reacted as raw materials to obtain PA6Q salt; then, hexamethylenediamine, terephthalic acid and PA6Q salt are mixed and prepolymerized and polycondensed in sequence to obtain PA6Z resin;

[0024] The chemical structure of 6Q monomer is .

[0025] The PA6Z resin prepared by the method of the present invention has high mechanical properties, thermal stability, low water absorption, and high dimensional stability. The specific analysis is as follows:

[0026] Tensile Strength and Elongation at Break: Because the rigidity of 6Q segments lies between that of aliphatic segments and aromatic benzene ring segments, the introduction of 6Q segments into the polymer reduces the proportion of flexible alkyl chains, leading to an increase in overall polymer strength. Furthermore, compared to segments containing benzene rings, 6Q segments are more compliant. Therefore, their introduction enhances polymer chain mobility and makes relative displacement more likely, impacting polymer strength. Therefore, increasing the 6Q segment content promotes improved tensile strength in PA6Z. The gradual increase in elongation at break is due to the brittle fracture of rigid benzene rings when stretched, resulting in PA6Z's low elongation at break. The introduction of 6Q segments enhances the flexibility of the PA6Z molecular chain, resulting in a higher elongation at break.

[0027] Bending strength and bending modulus: Since the rigidity of the 6Q segment itself is higher than that of the hexamethylenediamine segment, the bending strength and bending modulus of PA6Z are improved after the addition of the 6Q segment.

[0028] Impact strength: Impact strength is a parameter that characterizes the toughness of polymers. The addition of 6Q chain segments increases the flexibility and mobility of the PA6Z molecular chain, while inducing the generation of a greater degree of silver shear bands, thereby absorbing greater impact energy, so the impact strength gradually increases.

[0029] Water absorption rate: After the addition of 6Q chain segments, the mobility of the polymer molecular chain is enhanced, which promotes the crystallization of the polymer and weakens the increase in water absorption rate caused by the change in amide group density to a certain extent, so the water absorption rate of PA6Z is reduced.

[0030] Solvent resistance: The interaction between PA6Z molecular chains is strong and the arrangement tends to be dense, making it difficult for most organic solvent molecules to penetrate.

[0031] Thermal stability (melt index, initial degradation temperature, heat deformation temperature): Because the addition of 6Q chain segments increases the rigidity and density of the polymer molecular chain, the interaction force between polymer molecules is enhanced, and the mobility of the polymer molecular chain is also improved, thereby enhancing its crystallization ability (the rigid part provides the driving force for crystallization, and the flexible part gives local mobility). The rigid chain segment (diyne structure) partially restricts the movement of the chain segment and has high bond energy. The heat resistance of the polymer is closely related to the density of the molecular chain arrangement. The denser the molecular chain arrangement, the stronger the interaction force between the PA6Z molecular chains, thereby improving the heat resistance of PA6Z.

[0032] Dimensional stability (thermal linear expansion): By introducing a relatively rigid segment 6Q into the molecular chain, the crystalline polymer has a more compact molecular structure, which improves the linearity of the polymer molecular skeleton. The molecular axis is almost in the same plane and has a rod-like structure. It is rigid and easy to crystallize, resulting in very little expansion in the direction of the molecular chain. Therefore, as the temperature rises, the thermal expansion perpendicular to the molecular chain will be suppressed. At the same time, flexible monomers are used to eliminate the thermal stress generated by the rigid molecular chain and improve the flexibility of the material, thereby reducing the thermal linear expansion coefficient of PA6Z.

[0033] The preparation method of the semi-aromatic polyamide-based composite material described above, the specific preparation process of PA6Z resin is as follows:

[0034] (1) 1,5-Hexadiyne, NaN3 and catalyst (cat.) were added to solvent I and subjected to click chemistry reaction at 40-50°C for 12-24 hours to obtain product A;

[0035] (2) Product A, CeCl3·7H2O, and substance X are added to solvent II and reacted at 60–80°C for 24–48 h to obtain 6Q monomer; substance X is NaI, KI, or RbI;

[0036] (3) Add 6Q monomer, terephthalic acid and distilled water into a normal pressure reactor, react at a constant temperature of 70-80°C for 2-5 hours, adjust the pH value of the solution to neutral, evaporate and concentrate, cool and crystallize, filter and collect the mother liquor, and dry it in a vacuum oven at 101-105°C to obtain PA6Q salt powder;

[0037] (4) Hexamethylenediamine, terephthalic acid, benzoic acid (only as a molecular weight regulator), PA6Q salt and distilled water are added to the reactor, and the inert gas is purged for 10 to 30 minutes. Then, the inert gas is filled in the reactor to 0.4 to 0.6 MPa, and heating is started under stirring. When the pressure in the reactor reaches 2.0 to 3.0 MPa, the inert gas is stopped, the excess water vapor is discharged and the pressure in the reactor is maintained stable. When the temperature in the reactor reaches 200 to 250 ° C, the pressure is maintained at this temperature for 1.5 to 5 hours to obtain a prepolymer;

[0038] (5) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.11 ~ -0.04MPa, reacted at 200 ~ 220 ° C for 4 ~ 8 hours, discharged through an extruder at 290 ~ 308 ° C, and pelletized to obtain PA6Z resin.

[0039] A method for preparing a semi-aromatic polyamide-based composite material as described above, wherein in step (1), solvent I is methanol, ethanol or isopropanol, the catalyst is CuI or CuBr, and the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst is 1:2.5~4:10~50:0.1~0.5;

[0040] In step (2), solvent II is acetonitrile, tetrahydrofuran, N,N-dimethylformamide or dimethyl sulfoxide, and the molar ratio of product A, CeCl3·7H2O, substance X and solvent II is 1:3~3.6:18~24:200~1000;

[0041] In step (3), the molar ratio of 6Q monomer, terephthalic acid and distilled water is 1:1.01-1.11:2-4;

[0042] In step (4), the inert gas is helium or argon, and the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water is 1:1~1.1:0.05~0.15:2~5:10~30.

[0043] In the above-mentioned method for preparing a semi-aromatic polyamide-based composite material, the chemical structure of the prepolymer in step (4) is as follows:

[0044] ;

[0045] Among them, x>0, y>0, x+y=1, m≤40.

[0046] Principle of the invention:

[0047] In the present invention, after a diyne structure is introduced into the PA6Z resin matrix to replace a part of the pure alkyl chain, the thermal stability and mechanical properties of the prepared composite material (i.e., the semi-aromatic polyamide-based composite material) are significantly changed.

[0048] First, the PA6Z resin matrix obtained after introducing the 6Q segment into the polymer has excellent heat resistance, which makes the prepared composite material have excellent thermal stability.

[0049] Secondly, the mechanical properties of composite materials have also been greatly improved, specifically:

[0050] Tensile strength: ① The rigid characteristics of the diyne structure in the PA6Z resin matrix enhance the inter-molecular chain force of the skeleton structure. When the bonding force between the reinforcement material and the PA6Z matrix resin is relatively good, the diyne structure will limit the deformation of the PA6Z matrix resin and bear more stress and load, thereby improving the tensile strength of the composite material; ② Due to the introduction of the diyne structure in the PA6Z resin matrix, the interfacial interaction with the reinforcement material is improved, the surface fracture energy of the composite material is increased, and the resistance to extracting the reinforcement material from the PA6Z matrix resin is greater, thereby increasing the tensile strength of the composite material.

[0051] Elongation at break: This primarily impacts composite material performance through changes in the resin matrix. In PA6Z-based composite systems, the introduction of diacetylene structures achieves a molecular-scale balance of rigidity and flexibility. While maintaining interfacial bonding strength with the reinforcement, its moderate segmental flexibility facilitates localized molecular chain orientation and slip during stress transfer. The rigid components in the structure maintain material integrity by limiting plastic deformation. This synergistic effect at the molecular level results in composite materials exhibiting superior elongation at break performance compared to fully aromatic systems.

[0052] Bending performance: The introduction of diyne structure increases the rigidity of the PA6Z resin matrix molecular chain and the interaction between it and the reinforcement, making the bonding force between PA6Z resin and reinforcement material stronger. When the composite material is subjected to bending stress, it can effectively resist deformation, thereby simultaneously improving the bending strength and modulus.

[0053] Flexural strength and flexural modulus: When the composite is subjected to bending stress, the PA6Z matrix resin undergoes plastic deformation, allowing the diacetylene structure to partially dissipate the stress. The diacetylene structure, which bears stress and load across the composite cross-section, interacts with the reinforcement material, increasing the composite's ability to withstand bending stress. Due to the strong bond between the PA6Z matrix and the reinforcement material, the composite's deformation under constant stress is significantly reduced, significantly improving its flexural modulus.

[0054] Impact strength: The introduction of diyne structures into the resin matrix improves the impact strength of the composite material through two mechanisms: on the one hand, the molecular chain with its moderate rigidity-flexibility balance allows the PA6Z matrix resin to absorb energy through local deformation when the composite material is impacted; on the other hand, the diyne structures in the PA6Z resin act as stress concentration points, inducing the formation of silver streaks and shear bands. These microscopic deformation processes require a large amount of energy, thereby significantly improving the impact strength of the material.

[0055] Beneficial effects:

[0056] The invention discloses a method for preparing a semi-aromatic polyamide-based composite material. By designing the molecular structure of the PA6Z resin matrix, the mechanical properties and heat resistance of the composite material are improved. The process is controllable and the product performance is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The synthetic route diagram of 6Q monomer;

[0058] Figure 2 The H NMR spectrum of 6Q monomer ( 1 H NMR) spectra;

[0059] Figure 3 The C NMR spectrum of 6Q monomer ( 13 C NMR) spectra;

[0060] Figure 4 The synthetic route diagram of PA6Q salt;

[0061] Figure 5 The NMR spectrum of PA6Q salt is ( 1 H NMR) spectra;

[0062] Figure 6 This is the synthetic route diagram of PA6Z resin;

[0063] Figure 7 The NMR spectrum of PA6Z resin ( 1 H NMR) diagram. DETAILED DESCRIPTION

[0064] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0065] Performance test method:

[0066] Water absorption: According to GB / T 1034-2008 standard.

[0067] Solvent resistance: The test method is in accordance with ASTM D471 (immersion test). The test solvents are formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine.

[0068] Linear expansion coefficient: tested according to GB / T36800.2-2018 standard.

[0069] Melt index: According to GB / T 3682.1-2018 standard (the result needs to be converted into units).

[0070] Initial degradation temperature (TG): The thermal stability of the sample was analyzed using a thermogravimetric analyzer. An appropriate amount of sample was placed in a crucible and tested in a nitrogen atmosphere at a temperature of 30-700°C and a heating rate of 20°C / min.

[0071] Heat deformation temperature: According to GB / T 1634.1-2004 standard, the load is 0.45MPa.

[0072] Mechanical properties: Tensile properties and elongation at break are tested according to GB / T 1040-2006; flexural strength and flexural modulus are tested according to GB / T 9341-2008; impact strength is tested according to GB / T 1843-2008.

[0073] In the above test method, if the sample is a semi-aromatic polyamide-based composite material sample, before testing, the prepared semi-aromatic polyamide-based composite material sample needs to be dried in a vacuum oven at 70°C for 24 hours and then placed in a plastic injection molding equipment for injection molding.

[0074] Glass fiber specifications: 3mm in length; 10μm in diameter, manufacturer: Shandong Taishan Glass Fiber Co., Ltd.

[0075] Carbon fiber specifications: T700-12K, manufacturer: Japan Toray Corporation.

[0076] Example 1

[0077] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0078] (1) Preparation of raw materials:

[0079] 1,5-Hexanediyne (CAS 628-16-0); NaN3 (CAS 26628-22-8); CuI as catalyst; methanol as solvent I; CeCl3·7H2O (CAS 18618-55-8); NaI as substance X; acetonitrile as solvent II; terephthalic acid; distilled water; hexamethylenediamine; benzoic acid;

[0080] (2) 1,5-hexadiyne, NaN3 and catalyst were added to solvent I and subjected to a click chemistry reaction at 40°C for 24 hours to obtain product A; wherein the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst was 1:2.5:10:0.1;

[0081] (3) Product A, CeCl3·7H2O, and substance X were added to solvent II and reacted at 60°C for 48 h to obtain 6Q monomer; wherein the molar ratio of product A, CeCl3·7H2O, substance X, and solvent II was 1:3:18:200;

[0082] The chemical structure of the prepared 6Q monomer is .

[0083] (4) If Figures 4 and 5 As shown, 6Q monomer, terephthalic acid and distilled water were added to a normal pressure reactor, and the reaction was carried out at a constant temperature of 70°C for 5 hours. The pH value of the solution was adjusted to neutral, and the solution was evaporated and concentrated, then cooled and crystallized. The mother liquor was filtered and collected, and dried in a vacuum oven at 101°C to obtain PA6Q salt powder; wherein the molar ratio of 6Q monomer, terephthalic acid and distilled water was 1:1.01:2;

[0084] (5) If Figures 6 and 7 As shown, hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water are added to a reactor, and helium is purged for 10 minutes. Then, helium is filled in the reactor to 0.6 MPa, and heating is started under stirring. When the pressure in the reactor reaches 2 MPa, helium filling is stopped, excess water vapor is discharged and the pressure in the reactor is maintained stable. When the temperature in the reactor reaches 200°C, the pressure is maintained at this temperature for 5 hours to obtain a prepolymer; wherein the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water is 1:1:0.15:2:10;

[0085] The chemical structure of the prepared prepolymer is as follows:

[0086] ;

[0087] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.11 MPa, reacted at 200 °C for 8 h, discharged through an extruder at 290 °C, and pelletized to obtain PA6Z resin, i.e., semi-aromatic polyamide material.

[0088] The chemical structure of the prepared semi-aromatic polyamide material is:

[0089] ;

[0090] The semi-aromatic polyamide material is insoluble in formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the water absorption rate of the semi-aromatic polyamide material is 0.2%, the linear expansion coefficient is 10ppm / ℃, the melt index is 40g / 10min, the initial degradation temperature is 450℃, and the heat deformation temperature is 200℃; the semi-aromatic polyamide material has a tensile strength of 50MPa, an elongation at break of 3.3%, a flexural strength of 98MPa, a flexural modulus of 2400MPa, and an impact strength of 5.8KJ / m 2 .

[0091] Example 2

[0092] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0093] (1) Preparation of raw materials:

[0094] 1,5-Hexanediyne (CAS 628-16-0); NaN3 (CAS 26628-22-8); CuI as catalyst; methanol as solvent I; CeCl3·7H2O (CAS 18618-55-8); NaI as substance X; acetonitrile as solvent II; terephthalic acid; distilled water; hexamethylenediamine; benzoic acid;

[0095] (2) If Figure 1 As shown, 1,5-hexadiyne, NaN3 and a catalyst were added to solvent I, and a click chemistry reaction was carried out at 42°C for 21 hours to obtain product A; wherein the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst was 1:2.8:20:0.2;

[0096] (3) Product A, CeCl3·7H2O, and substance X were added to solvent II and reacted at 64°C for 44 h to obtain 6Q monomer; wherein the molar ratio of product A, CeCl3·7H2O, substance X, and solvent II was 1:3.1:19:400;

[0097] like Figures 1-3 As shown, the chemical structure of the prepared 6Q monomer is .

[0098] (4) 6Q monomer, terephthalic acid and distilled water were added to a normal pressure reactor, and the reaction was carried out at a constant temperature of 72°C for 4 hours. The pH value of the solution was adjusted to neutral, and the solution was cooled and crystallized after evaporation and concentration. The mother liquor was filtered and collected, and dried in a vacuum oven at 101°C to obtain PA6Q salt powder; wherein the molar ratio of 6Q monomer, terephthalic acid and distilled water was 1:1.03:2.4;

[0099] (5) Hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water were added to the reactor, and helium was purged for 13 minutes. Then, helium was filled in the reactor to 0.55 MPa, and heating was started under stirring. When the pressure in the reactor reached 2.2 MPa, helium filling was stopped, excess water vapor was discharged and the pressure in the reactor was maintained stable. When the temperature in the reactor reached 210°C, the pressure was maintained at this temperature for 4 hours to obtain a prepolymer; wherein the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water was 1:1.02:0.13:2.5:14;

[0100] The chemical structure of the prepared prepolymer is as follows:

[0101] ;

[0102] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.09 MPa, reacted at 204 °C for 7 h, discharged through an extruder at 293 °C, and pelletized to obtain PA6Z resin, i.e., semi-aromatic polyamide material.

[0103] The chemical structure of the prepared semi-aromatic polyamide material is:

[0104] ;

[0105] The semi-aromatic polyamide material is insoluble in formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the water absorption rate of the semi-aromatic polyamide material is 0.22%, the linear expansion coefficient is 10.9ppm / ℃, the melt index is 50g / 10min, the initial degradation temperature is 451℃, and the heat deformation temperature is 220℃; the semi-aromatic polyamide material has a tensile strength of 52MPa, an elongation at break of 3.5%, a flexural strength of 100MPa, a flexural modulus of 2600MPa, and an impact strength of 6.1KJ / m 2 .

[0106] Example 3

[0107] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0108] (1) Preparation of raw materials:

[0109] 1,5-Hexanediyne (CAS 628-16-0); NaN3 (CAS 26628-22-8); CuI as catalyst; ethanol as solvent I; CeCl3·7H2O (CAS 18618-55-8); substance X as KI; tetrahydrofuran as solvent II; terephthalic acid; distilled water; hexamethylenediamine; benzoic acid;

[0110] (2) 1,5-hexadiyne, NaN3 and catalyst were added to solvent I and subjected to click chemistry reaction at 44°C for 19 h to obtain product A; wherein the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst was 1:3.2:30:0.3;

[0111] (3) Product A, CeCl3·7H2O, and substance X were added to solvent II and reacted at 68°C for 38 h to obtain 6Q monomer; wherein the molar ratio of product A, CeCl3·7H2O, substance X, and solvent II was 1:3.2:20:600;

[0112] The chemical structure of the prepared 6Q monomer is .

[0113] (4) 6Q monomer, terephthalic acid and distilled water were added to a normal pressure reactor, and the reaction was carried out at a constant temperature of 74°C for 3 hours. The pH value of the solution was adjusted to neutral, and the solution was cooled and crystallized after evaporation and concentration. The mother liquor was filtered and collected, and dried in a vacuum oven at 102°C to obtain PA6Q salt powder; wherein the molar ratio of 6Q monomer, terephthalic acid and distilled water was 1:1.05:3;

[0114] (5) Hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water were added to the reactor, and helium was purged for 17 minutes. Then, helium was filled in the reactor to 0.5 MPa, and heating was started under stirring. When the pressure in the reactor reached 2.4 MPa, helium filling was stopped, excess water vapor was discharged and the pressure in the reactor was maintained stable. When the temperature in the reactor reached 220°C, the pressure was maintained at this temperature for 3 hours to obtain a prepolymer; wherein the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water was 1:1.04:0.11:3:20;

[0115] The chemical structure of the prepared prepolymer is as follows:

[0116] ;

[0117] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.07 MPa, reacted at 208 °C for 6 h, discharged through an extruder at 296 °C, and pelletized to obtain PA6Z resin, i.e., semi-aromatic polyamide material.

[0118] The chemical structure of the prepared semi-aromatic polyamide material is:

[0119] ;

[0120] The semi-aromatic polyamide material is insoluble in formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the water absorption rate of the semi-aromatic polyamide material is 0.24%, the linear expansion coefficient is 11.7ppm / ℃, the melt index is 59g / 10min, the initial degradation temperature is 453℃, and the heat deformation temperature is 238℃; the semi-aromatic polyamide material has a tensile strength of 54MPa, an elongation at break of 3.7%, a flexural strength of 102MPa, a flexural modulus of 2800MPa, and an impact strength of 6.4KJ / m 2 .

[0121] Example 4

[0122] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0123] (1) Preparation of raw materials:

[0124] 1,5-Hexadiyne (CAS 628-16-0); NaN3 (CAS 26628-22-8); CuBr as catalyst; ethanol as solvent I; CeCl3·7H2O (CAS 18618-55-8); KI as substance X; N,N-dimethylformamide as solvent II; terephthalic acid; distilled water; hexamethylenediamine; benzoic acid;

[0125] (2) 1,5-hexadiyne, NaN3 and catalyst were added to solvent I and subjected to click chemistry reaction at 46°C for 17 h to obtain product A; wherein the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst was 1:3.5:35:0.4;

[0126] (3) Product A, CeCl3·7H2O, and substance X were added to solvent II and reacted at 72°C for 36 h to obtain 6Q monomer; wherein the molar ratio of product A, CeCl3·7H2O, substance X, and solvent II was 1:3.3:21:700;

[0127] The chemical structure of the prepared 6Q monomer is .

[0128] (4) 6Q monomer, terephthalic acid and distilled water were added to a normal pressure reactor, and the reaction was carried out at a constant temperature of 76°C for 2.5 hours. The pH value of the solution was adjusted to neutral, and the solution was cooled and crystallized after evaporation and concentration. The mother liquor was filtered and collected, and dried in a vacuum oven at 103°C to obtain PA6Q salt powder; wherein the molar ratio of 6Q monomer, terephthalic acid and distilled water was 1:1.07:3.3;

[0129] (5) Hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water were added to the reactor, purged with argon for 20 min, and then filled with argon to 0.45 MPa in the reactor, and started heating under stirring. When the pressure in the reactor reached 2.6 MPa, helium filling was stopped, excess water vapor was discharged and the pressure in the reactor was maintained stable. When the temperature in the reactor reached 230 °C, the pressure was maintained at this temperature for 2.5 h to obtain a prepolymer; wherein the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water was 1:1.06:0.09:3.5:23;

[0130] The chemical structure of the prepared prepolymer is as follows:

[0131] ;

[0132] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.06 MPa, reacted at 212 °C for 5 h, discharged through an extruder at 300 °C, and pelletized to obtain PA6Z resin, i.e., semi-aromatic polyamide material.

[0133] The chemical structure of the prepared semi-aromatic polyamide material is:

[0134] ;

[0135] The semi-aromatic polyamide material is insoluble in formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the water absorption rate of the semi-aromatic polyamide material is 0.25%, the linear expansion coefficient is 12.5ppm / ℃, the melt index is 67g / 10min, the initial degradation temperature is 455℃, and the heat deformation temperature is 250℃; the semi-aromatic polyamide material has a tensile strength of 56MPa, an elongation at break of 3.9%, a flexural strength of 103MPa, a flexural modulus of 3000MPa, and an impact strength of 6.8KJ / m 2 .

[0136] Example 5

[0137] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0138] (1) Preparation of raw materials:

[0139] 1,5-Hexadiyne (CAS 628-16-0); NaN3 (CAS 26628-22-8); CuBr as catalyst; isopropyl alcohol as solvent I; CeCl3·7H2O (CAS 18618-55-8); substance X as RbI; N,N-dimethylformamide as solvent II; terephthalic acid; distilled water; hexamethylenediamine; benzoic acid;

[0140] (2) 1,5-hexadiyne, NaN3 and a catalyst were added to solvent I and subjected to a click chemistry reaction at 48°C for 15 h to obtain product A; wherein the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst was 1:3.7:44:0.45;

[0141] (3) Product A, CeCl3·7H2O, and substance X were added to solvent II and reacted at 76°C for 39 h to obtain 6Q monomer; wherein the molar ratio of product A, CeCl3·7H2O, substance X, and solvent II was 1:3.5:23:900;

[0142] The chemical structure of the prepared 6Q monomer is .

[0143] (4) 6Q monomer, terephthalic acid and distilled water were added to a normal pressure reactor, and the reaction was carried out at a constant temperature of 78°C for 2 hours. The pH value of the solution was adjusted to neutral, and the solution was cooled and crystallized after evaporation and concentration. The mother liquor was filtered and collected, and dried in a vacuum oven at 104°C to obtain PA6Q salt powder; wherein the molar ratio of 6Q monomer, terephthalic acid and distilled water was 1:1.09:3.7;

[0144] (5) Hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water were added to the reactor, purged with argon for 25 minutes, and then filled with argon to 0.43 MPa, and started to heat under stirring. When the pressure in the reactor reached 2.8 MPa, the argon filling was stopped, the excess water vapor was discharged and the pressure in the reactor was maintained stable. When the temperature in the reactor reached 240°C, the pressure was maintained at this temperature for 2 hours to obtain a prepolymer; wherein the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water was 1:1.08:0.07:4.2:27;

[0145] The chemical structure of the prepared prepolymer is as follows:

[0146] ;

[0147] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.05 MPa, reacted at 216 ° C for 4 hours, discharged through an extruder at 304 ° C, and pelletized to obtain PA6Z resin, i.e., semi-aromatic polyamide material.

[0148] The chemical structure of the prepared semi-aromatic polyamide material is:

[0149] ;

[0150] The semi-aromatic polyamide material is insoluble in formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the water absorption rate of the semi-aromatic polyamide material is 0.27%, the linear expansion coefficient is 13.7ppm / ℃, the melt index is 73g / 10min, the initial degradation temperature is 457℃, and the heat deformation temperature is 277℃; the semi-aromatic polyamide material has a tensile strength of 58MPa, an elongation at break of 4.3%, a flexural strength of 105MPa, a flexural modulus of 3300MPa, and an impact strength of 7.1KJ / m 2 .

[0151] Example 6

[0152] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0153] (1) Preparation of raw materials:

[0154] 1,5-Hexadiyne (CAS 628-16-0); NaN3 (CAS 26628-22-8); CuBr as catalyst; isopropyl alcohol as solvent I; CeCl3·7H2O (CAS 18618-55-8); substance X as RbI; N,N-dimethylformamide as solvent II; terephthalic acid; distilled water; hexamethylenediamine; benzoic acid;

[0155] (2) 1,5-hexadiyne, NaN3 and catalyst were added to solvent I and subjected to click chemistry reaction at 50°C for 12 hours to obtain product A; wherein the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst was 1:4:50:0.5;

[0156] (3) Product A, CeCl3·7H2O, and substance X were added to solvent II and reacted at 80°C for 24 h to obtain 6Q monomer; wherein the molar ratio of product A, CeCl3·7H2O, substance X, and solvent II was 1:3.6:24:1000;

[0157] The chemical structure of the prepared 6Q monomer is .

[0158] (4) 6Q monomer, terephthalic acid and distilled water were added to a normal pressure reactor, and the reaction was carried out at a constant temperature of 80°C for 1 hour. The pH value of the solution was adjusted to neutral, and the solution was cooled and crystallized after evaporation and concentration. The mother liquor was filtered and collected, and dried in a vacuum oven at 105°C to obtain PA6Q salt powder; wherein the molar ratio of 6Q monomer, terephthalic acid and distilled water was 1:1.11:4;

[0159] (5) Hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water were added to the reactor, purged with argon for 30 minutes, and then filled with argon to 0.4 MPa, and started to heat under stirring. When the pressure in the reactor reached 3 MPa, the argon filling was stopped, the excess water vapor was discharged and the pressure in the reactor was maintained stable. When the temperature in the reactor reached 250°C, the pressure was maintained at this temperature for 1.5 hours to obtain a prepolymer; wherein the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water was 1:1.1:0.05:5:30;

[0160] The chemical structure of the prepared prepolymer is as follows:

[0161] ;

[0162] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.04 MPa, reacted at 220 °C for 4 h, discharged through an extruder at 308 °C, and pelletized to obtain PA6Z resin, i.e., semi-aromatic polyamide material.

[0163] The chemical structure of the prepared semi-aromatic polyamide material is:

[0164] ;

[0165] The semi-aromatic polyamide material is insoluble in formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the water absorption rate of the semi-aromatic polyamide material is 0.3%, the linear expansion coefficient is 14ppm / ℃, the melt index is 80g / 10min, the initial degradation temperature is 460℃, and the heat deformation temperature is 300℃; the semi-aromatic polyamide material has a tensile strength of 60MPa, an elongation at break of 4.5%, a flexural strength of 106MPa, a flexural modulus of 3600MPa, and an impact strength of 7.6KJ / m 2 .

[0166] Example 7

[0167] A method for preparing a semi-aromatic polyamide-based composite material, comprising the following steps:

[0168] (1) Preparation of raw materials:

[0169] PA6Z resin is the PA6Z resin of Example 1;

[0170] The reinforcement material is glass fiber;

[0171] (2) The PA6Z resin was vacuum dried at 70°C for 72 h and then mixed evenly with the reinforcement material. The composite material was obtained by extrusion and pelletization. The extrusion temperature was 290°C and the extrusion rate was 50 r / min. The mass ratio of the vacuum-dried PA6Z resin to the reinforcement material was 1:0.05.

[0172] The prepared semi-aromatic polyamide-based composite material has a melt index of 20g / 10min, an initial degradation temperature of 470℃, a heat deformation temperature of 290℃, a tensile strength of 100MPa, an elongation at break of 3.1%, a flexural strength of 140MPa, a flexural modulus of 5800MPa, and an impact strength of 6.9KJ / m 2 .

[0173] Example 8

[0174] A method for preparing a semi-aromatic polyamide-based composite material, comprising the following steps:

[0175] (1) Preparation of raw materials:

[0176] The PA6Z resin is the PA6Z resin of Example 2;

[0177] The reinforcement material is glass fiber;

[0178] (2) The PA6Z resin was vacuum dried at 72 °C for 60 h and then mixed evenly with the reinforcement material, and then extruded and pelletized to obtain a composite material; the extrusion temperature was 292 °C and the extrusion rate was 45 r / min; the mass ratio of the vacuum-dried PA6Z resin to the reinforcement material was 1:0.15.

[0179] The prepared semi-aromatic polyamide-based composite material has a melt index of 24g / 10min, an initial degradation temperature of 475℃, a heat deformation temperature of 300℃, a tensile strength of 130MPa, an elongation at break of 3.3%, a flexural strength of 170MPa, a flexural modulus of 7100MPa, and an impact strength of 7.2KJ / m 2 .

[0180] Example 9

[0181] A method for preparing a semi-aromatic polyamide-based composite material, comprising the following steps:

[0182] (1) Preparation of raw materials:

[0183] The PA6Z resin is the PA6Z resin of Example 3;

[0184] The reinforcement material is glass fiber;

[0185] (2) The PA6Z resin was vacuum dried at 74 °C for 50 h and then mixed evenly with the reinforcement material. The composite material was obtained by extrusion and pelletization. The extrusion temperature was 294 °C and the extrusion rate was 40 r / min. The mass ratio of the vacuum-dried PA6Z resin to the reinforcement material was 1:0.35.

[0186] The prepared semi-aromatic polyamide-based composite material has a melt index of 28g / 10min, an initial degradation temperature of 480℃, a heat deformation temperature of 310℃, a tensile strength of 160MPa, an elongation at break of 3.5%, a flexural strength of 200MPa, a flexural modulus of 9800MPa, and an impact strength of 7.7KJ / m 2 .

[0187] Example 10

[0188] A method for preparing a semi-aromatic polyamide-based composite material, comprising the following steps:

[0189] (1) Preparation of raw materials:

[0190] The PA6Z resin is the PA6Z resin of Example 4;

[0191] The reinforcement material is carbon fiber;

[0192] (2) The PA6Z resin was vacuum dried at 76 °C for 40 h and then mixed evenly with the reinforcement material, and then extruded and pelletized to obtain a composite material; the extrusion temperature was 298 °C and the extrusion rate was 35 r / min; the mass ratio of the vacuum-dried PA6Z resin to the reinforcement material was 1:0.5.

[0193] The prepared semi-aromatic polyamide-based composite material has a melt index of 32g / 10min, an initial degradation temperature of 483℃, a heat deformation temperature of 320℃, a tensile strength of 190MPa, an elongation at break of 3.6%, a flexural strength of 230MPa, a flexural modulus of 11600MPa, and an impact strength of 8KJ / m 2 .

[0194] Example 11

[0195] A method for preparing a semi-aromatic polyamide-based composite material, comprising the following steps:

[0196] (1) Preparation of raw materials:

[0197] The PA6Z resin is the PA6Z resin of Example 5;

[0198] The reinforcement material is carbon fiber;

[0199] (2) The PA6Z resin was vacuum dried at 78 °C for 30 h and then mixed evenly with the reinforcement material. The composite material was obtained by extrusion and pelletization. The extrusion temperature was 305 °C and the extrusion rate was 33 r / min. The mass ratio of the vacuum-dried PA6Z resin to the reinforcement material was 1:0.75.

[0200] The prepared semi-aromatic polyamide-based composite material has a melt index of 35g / 10min, an initial degradation temperature of 487℃, a heat deformation temperature of 330℃, a tensile strength of 220MPa, an elongation at break of 3.8%, a flexural strength of 260MPa, a flexural modulus of 14100MPa, and an impact strength of 8.5KJ / m 2 .

[0201] Example 12

[0202] A method for preparing a semi-aromatic polyamide-based composite material, comprising the following steps:

[0203] (1) Preparation of raw materials:

[0204] The PA6Z resin is the PA6Z resin of Example 6;

[0205] The reinforcement material is carbon fiber;

[0206] (2) The PA6Z resin was vacuum dried at 80°C for 24 h and then mixed evenly with the reinforcement material, and then extruded and pelletized to obtain a composite material; the extrusion temperature was 310°C and the extrusion rate was 30 r / min; the mass ratio of the vacuum-dried PA6Z resin to the reinforcement material was 1:1.

[0207] The prepared semi-aromatic polyamide-based composite material has a melt index of 38g / 10min, an initial degradation temperature of 490℃, a heat deformation temperature of 340℃, a tensile strength of 250MPa, an elongation at break of 3.9%, a flexural strength of 280MPa, a flexural modulus of 16800MPa, and an impact strength of 8.9KJ / m 2 .

Claims

1. A method for preparing a semi-aromatic polyamide-based composite material, characterized in that: The PA6Z resin is vacuum dried and then mixed with the reinforcement material, and then extruded and pelletized to obtain a composite material; The chemical structure of PA6Z resin is as follows: ； Among them, x>0, y>0, x+y=1, 40≤n≤500.

2. The method for preparing a semi-aromatic polyamide-based composite material according to claim 1, wherein: The vacuum drying temperature is 70~80℃ and the time is 24~72h.

3. The method for preparing a semi-aromatic polyamide-based composite material according to claim 1, wherein: The reinforcement material is glass fiber or carbon fiber.

4. The method for preparing a semi-aromatic polyamide-based composite material according to claim 1, wherein: The extrusion temperature is 290~310℃, and the extrusion rate is 30~50 r / min.

5. The method for preparing a semi-aromatic polyamide-based composite material according to claim 1, wherein: The mass ratio of PA6Z resin and reinforcement material after vacuum drying is 1:0.05~1.

6. The method for preparing a semi-aromatic polyamide-based composite material according to claim 1, characterized in that: The semi-aromatic polyamide-based composite material has a melt index of 20~38g / 10min, an initial degradation temperature of 470~490℃, a heat deformation temperature of 290~340℃, a tensile strength of 100~250MPa, an elongation at break of 3.1%~3.9%, a flexural strength of 140~280MPa, a flexural modulus of 5800~16800MPa, and an impact strength of 6.9~8.9KJ / m 2 .

7. The method for preparing a semi-aromatic polyamide-based composite material according to claim 1, characterized in that: The preparation method of PA6Z resin is as follows: first, 6Q monomer and terephthalic acid are used as raw materials to react to obtain PA6Q salt; then, hexamethylenediamine, terephthalic acid and PA6Q salt are mixed and prepolymerized and polycondensed in sequence to obtain PA6Z resin; The chemical structure of 6Q monomer is .

8. The method for preparing a semi-aromatic polyamide-based composite material according to claim 7, characterized in that: The specific preparation process of PA6Z resin is as follows: (1) 1,5-Hexadiyne, NaN3 and catalyst were added to solvent I and subjected to click chemistry reaction at 40-50°C for 12-24 hours to obtain product A; (2) Product A, CeCl3·7H2O, and substance X are added to solvent II and reacted at 60–80°C for 24–48 h to obtain 6Q monomer; substance X is NaI, KI, or RbI; (3) Add 6Q monomer, terephthalic acid and distilled water into a normal pressure reactor, react at a constant temperature of 70-80°C for 2-5 hours, adjust the pH value of the solution to neutral, evaporate and concentrate, cool and crystallize, filter and collect the mother liquor, and dry it in a vacuum oven at 101-105°C to obtain PA6Q salt powder; (4) Hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water are added to the reactor, and the inert gas is purged for 10 to 30 minutes. Then, the inert gas is filled in the reactor to 0.4 to 0.6 MPa, and heating is started under stirring. When the pressure in the reactor reaches 2.0 to 3.0 MPa, the inert gas is stopped, the excess water vapor is discharged and the pressure in the reactor is maintained stable. When the temperature in the reactor reaches 200 to 250 ° C, the pressure is maintained at this temperature for 1.5 to 5 hours to obtain a prepolymer; (5) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.11 ~ -0.04MPa, reacted at 200 ~ 220 ° C for 4 ~ 8 hours, discharged through an extruder at 290 ~ 308 ° C, and pelletized to obtain PA6Z resin.

9. The method for preparing a semi-aromatic polyamide-based composite material according to claim 8, characterized in that: In step (1), solvent I is methanol, ethanol or isopropanol, the catalyst is CuI or CuBr, and the molar ratio of 1,5-hexadiyne, NaN3, solvent I and catalyst is 1:2.5~4:10~50:0.1~0.5; In step (2), solvent II is acetonitrile, tetrahydrofuran, N,N-dimethylformamide or dimethyl sulfoxide, and the molar ratio of product A, CeCl3·7H2O, substance X and solvent II is 1:3~3.6:18~24:200~1000; In step (3), the molar ratio of 6Q monomer, terephthalic acid and distilled water is 1:1.01-1.11:2-4; In step (4), the inert gas is helium or argon, and the molar ratio of hexamethylenediamine, terephthalic acid, benzoic acid, PA6Q salt and distilled water is 1:1~1.1:0.05~0.15:2~5:10~30.

10. The method for preparing a semi-aromatic polyamide-based composite material according to claim 8, characterized in that: The chemical structure of the prepolymer in step (4) is as follows: ； Among them, x>0, y>0, x+y=1, m≤40.

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