A semi-aromatic polyamide material and preparation method thereof

Abstract

The present invention relates to a semi-aromatic polyamide material and a preparation method thereof, belonging to the technical field of materials. The semi-aromatic polyamide material is a PA6Z resin, which is insoluble in organic solvents such as formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; the semi-aromatic polyamide material has a water absorption rate of 0.2-0.3%, a linear expansion coefficient of 10-14 ppm / °C, a melt index of 40-80 g / 10 min, an initial degradation temperature of 450-460°C, a heat deformation temperature of 200-300°C, a tensile strength of 50-60 MPa, an elongation at break of 3.3-4.5%, a flexural strength of 98-106 MPa, a flexural modulus of 2400-3600 MPa, and an impact strength of 5.8-7.6 KJ / m 2 The preparation method comprises: first, reacting 6Q monomer and terephthalic acid as raw materials to obtain PA6Q salt; then, mixing hexamethylenediamine, terephthalic acid, and PA6Q salt, and sequentially subjecting them to prepolymerization and polycondensation reactions to produce PA6Z resin. The product of the present invention combines high mechanical properties, thermal stability, low water absorption, and high dimensional stability; the preparation method is simple, safe, and reliable.

Description

Technical Field

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

[0002] As a typical type of specialty polyamide polymer, semi-aromatic polyamide has always attracted much attention due to its excellent comprehensive properties.

[0003] In recent years, the dramatic increase in operating temperatures within the engine compartments of turbocharged automobiles has placed even higher demands on the heat resistance of resin components, such as fuel hoses. Simultaneously, in the electronics and electrical sectors, with the trend toward lighter and smaller devices, and particularly the prevalence of surface mount technology, resins used in connectors and other applications must withstand higher reflow soldering temperatures. Due to concerns about the health and environmental hazards of lead, the concept of lead-free solder has been promoted worldwide, further increasing reflow soldering temperatures (reaching 270°C for short periods).

[0004] Since the amide bond and the methylene group adjacent to the amide bond in the semi-aromatic polyamide molecular chain are unstable, when the semi-aromatic polyamide molecules are exposed to factors such as heat and water, the amide bond and the methylene group may break, forming macromolecular oxides and alkyl free radicals. At this time, the polymer molecular chain will break or cross-link and degrade, causing the polymer molecular weight to decrease, thereby reducing the performance of the product and being greatly restricted in engineering applications.

[0005] In addition, as the electronics and electrical industry and the automotive industry demand higher performance, durability, and the actual physical and chemical environment of their products, higher requirements are placed on the mechanical properties, dimensional stability, and solvent resistance (chemical resistance) of materials.

[0006] Reference 1 (Influence of moisture on the viscoelastic relaxations in longaliphatic chain contained semiaromatic polyamide, (PA9-T) fiber [J]. Journal of Polymer Science Part B Polymer Physics, 2010, 41(22): 2878-91.) utilizes moisture to act as a plasticizer in the polymer PA9T matrix, destroying the strong hydrogen bonds between molecules and significantly reducing its glass transition temperature; however, its mechanical properties are poor.

[0007] Reference 2 (Synthesis and Characterization of High-Temperature Resistant PA6T Copolymers [J]. Engineering Plastics Application, 2013, 41(05): 14-20) synthesized several PA6T copolymers such as PA6T / 6, PA6T / 66, and PA6T / 6 / 66 by prepolymerization + solid phase polycondensation. However, the copolymers had poor dimensional stability (linear expansion coefficient was less than 7ppm / ℃) and poor solvent resistance.

[0008] Reference 3 (Synthesis and Characterization of Semi-aromatic Nylons Containing Naphthalene Rings and Long Methylene Chains [D], 2010) uses inexpensive domestic long-chain diamines and 2,6-naphthalenedicarboxylic acid as raw materials. A series of long-chain semi-aromatic high-temperature-resistant PA10N, PA11N, PA12N, and PA13N containing naphthalene rings are synthesized through salt formation, prepolymerization, and solid-phase condensation. However, the elongation at break is not high (the elongation at break is not higher than 3%).

[0009] Therefore, it is of great significance to research and develop semi-aromatic polyamides with high mechanical properties, thermal stability, low water absorption and high dimensional stability. Summary of the Invention

[0010] The purpose of the present invention is to solve the problems existing in the prior art and provide a semi-aromatic polyamide material and a preparation method thereof.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A semi-aromatic polyamide material, PA6Z resin, has the chemical structure shown below:

[0013] ;

[0014] 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.

[0015] As the preferred technical solution:

[0016] A semi-aromatic polyamide material as described above, wherein the semi-aromatic polyamide material is insoluble in an organic solvent, and the organic solvent is formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide, and pyridine;

[0017] The water absorption rate of semi-aromatic polyamide material is 0.2~0.3%, the linear expansion coefficient is 10~14ppm / ℃, the melt index is 40~80g / 10min, the initial degradation temperature is 450~460℃, and the heat deformation temperature is 200~300℃;

[0018] The tensile strength of semi-aromatic polyamide material is 50~60MPa, the elongation at break is 3.3~4.5%, the flexural strength is 98~106MPa, the flexural modulus is 2400~3600MPa, and the impact strength is 5.8~7.6KJ / m 2 .

[0019] The present invention also provides a method for preparing a semi-aromatic polyamide material, comprising: firstly reacting 6Q monomer and terephthalic acid as raw materials to obtain PA6Q salt; then mixing hexamethylenediamine, terephthalic acid and PA6Q salt and sequentially performing prepolymerization and polycondensation reactions to obtain PA6Z resin, i.e., a semi-aromatic polyamide material;

[0020] The chemical structure of 6Q monomer is .

[0021] As the preferred technical solution:

[0022] The preparation method of the semi-aromatic polyamide material as described above comprises the following specific steps:

[0023] (1) 1,5-Hexadiyne, NaN3 and catalyst (cat.) were added to solvent I and subjected to a click chemistry reaction at 40-50°C for 12-24 hours to obtain product A;

[0024] (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;

[0025] (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;

[0026] (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;

[0027] (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.

[0028] In the method for preparing a semi-aromatic polyamide material as described above, 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.

[0029] In the method for preparing a semi-aromatic polyamide material as described above, 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.

[0030] In the method for preparing a semi-aromatic polyamide material as described above, the molar ratio of 6Q monomer, terephthalic acid and distilled water in step (3) is 1:1.01~1.11:2~4.

[0031] In the method for preparing a semi-aromatic polyamide material as described above, the inert gas in step (4) 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.

[0032] In the above-mentioned method for preparing a semi-aromatic polyamide material, the chemical structure of the prepolymer in step (4) is as follows:

[0033] ;

[0034] Among them, x>0, y>0, x+y=1, m≤40.

[0035] Invention mechanism:

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Beneficial effects:

[0044] (1) A semi-aromatic polyamide material of the present invention has high mechanical properties, thermal stability, low water absorption and high dimensional stability;

[0045] (2) The method for preparing a semi-aromatic polyamide material of the present invention achieves efficient control and stability of the reaction through a two-step process, and the preparation is simple, safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The synthetic route diagram of 6Q monomer;

[0047] Figure 2 The H NMR spectrum of 6Q monomer ( 1 H NMR) spectra;

[0048] Figure 3 The C NMR spectrum of 6Q monomer ( 13 C NMR) spectra;

[0049] Figure 4 The synthetic route diagram of PA6Q salt;

[0050] Figure 5 The NMR spectrum of PA6Q salt is ( 1 H NMR) spectra;

[0051] Figure 6 This is the synthetic route diagram of PA6Z resin;

[0052] Figure 7 The NMR spectrum of PA6Z resin ( 1 H NMR) diagram. DETAILED DESCRIPTION

[0053] 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.

[0054] Performance test method:

[0055] Water absorption: According to GB / T 1034-2008 standard.

[0056] 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.

[0057] Linear expansion coefficient: tested according to GB / T36800.2-2018 standard.

[0058] Melt index: According to GB / T 3682.1-2018 standard (the result needs to be converted into units).

[0059] 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.

[0060] Heat deformation temperature: According to GB / T 1634.1-2004 standard, the load is 0.45MPa.

[0061] 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.

[0062] Example 1

[0063] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0064] (1) Preparation of raw materials:

[0065] 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;

[0066] (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;

[0067] (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;

[0068] The chemical structure of the prepared 6Q monomer is .

[0069] (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;

[0070] (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;

[0071] The chemical structure of the prepared prepolymer is as follows:

[0072] ;

[0073] (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.

[0074] The chemical structure of the prepared semi-aromatic polyamide material is:

[0075] ;

[0076] 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 .

[0077] Example 2

[0078] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0079] (1) Preparation of raw materials:

[0080] 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;

[0081] (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;

[0082] (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;

[0083] like Figures 1-3 As shown, the chemical structure of the prepared 6Q monomer is .

[0084] (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;

[0085] (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;

[0086] The chemical structure of the prepared prepolymer is as follows:

[0087] ;

[0088] (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.

[0089] The chemical structure of the prepared semi-aromatic polyamide material is:

[0090] ;

[0091] 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 .

[0092] Example 3

[0093] A method for preparing a semi-aromatic polyamide material, comprising the following steps:

[0094] (1) Preparation of raw materials:

[0095] 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;

[0096] (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;

[0097] (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;

[0098] The chemical structure of the prepared 6Q monomer is .

[0099] (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;

[0100] (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;

[0101] The chemical structure of the prepared prepolymer is as follows: ;

[0102] (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.

[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 0.24%, 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 .

[0106] Example 4

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

[0108] (1) Preparation of raw materials:

[0109] 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;

[0110] (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;

[0111] (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;

[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 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;

[0114] (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;

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

[0116] ;

[0117] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.06 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.

[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 0.25%, 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 .

[0121] Example 5

[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; 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;

[0125] (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;

[0126] (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;

[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 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;

[0129] (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;

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

[0131] ;

[0132] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.05 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.

[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 0.27%, 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 .

[0136] Example 6

[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 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;

[0141] (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;

[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 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;

[0144] (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;

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

[0146] ;

[0147] (6) The prepolymer is transferred into a polycondensation reactor, vacuumed to -0.04 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.

[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 0.3%, 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 .

Claims

1. A semi-aromatic polyamide material, characterized in that: It is PA6Z resin, having the chemical structure shown below; ； Among them, x>0, y>0, x+y=1, 40≤n≤500.

2. A semi-aromatic polyamide material according to claim 1, characterized in that: Semi-aromatic polyamide materials are insoluble in organic solvents, such as formic acid, toluene, methanol, chloroform, tetrachloromethane, N,N-dimethylformamide, dimethyl sulfoxide and pyridine; The water absorption rate of semi-aromatic polyamide material is 0.2~0.3%, the linear expansion coefficient is 10~14ppm / ℃, the melt index is 40~80g / 10min, the initial degradation temperature is 450~460℃, and the heat deformation temperature is 200~300℃; The tensile strength of semi-aromatic polyamide material is 50~60MPa, the elongation at break is 3.3~4.5%, the flexural strength is 98~106MPa, the flexural modulus is 2400~3600MPa, and the impact strength is 5.8~7.6KJ / m 2 .

3. The method for preparing a semi-aromatic polyamide material according to claim 1 or 2, wherein: 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, i.e., semi-aromatic polyamide material; The chemical structure of 6Q monomer is .

4. The method for preparing a semi-aromatic polyamide material according to claim 3, wherein: The specific steps are 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.

5. The method for preparing a semi-aromatic polyamide material according to claim 4, 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.

6. The method for preparing a semi-aromatic polyamide material according to claim 4, characterized in that: 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.

7. The method for preparing a semi-aromatic polyamide material according to claim 4, characterized in that: In step (3), the molar ratio of 6Q monomer, terephthalic acid and distilled water is 1:1.01~1.11:2~4.

8. The method for preparing a semi-aromatic polyamide material according to claim 4, characterized in that: 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.

9. The method for preparing a semi-aromatic polyamide material according to claim 4, 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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