A method based on synergistic toughening of polyamides containing aliphatic and aromatic supramolecular segments

Abstract

The present invention provides a method for synergistically toughening polyamide based on aliphatic and aromatic supramolecular segments. A polyamide system containing aromatic and aliphatic supramolecular segments is constructed, and the regularity of the polymer chain is destroyed by introducing rigid-flexible supramolecular segments into the polyamide, effectively adjusting the stress distribution in the polymer. At the same time, appropriate supramolecular interactions can act as sacrificial bonds to dissipate energy, thereby improving the toughness of the material. In addition, supramolecular polyamide is obtained by utilizing the rigid-flexible supramolecular toughening strategy, and the crystallinity, microphase separation structure and energy dissipation capacity of the polymer can be precisely controlled by adjusting the ratio between the rigid-flexible supramolecular segments. The rigid-flexible supramolecular toughening strategy provided by the present invention is not limited to polyamide systems, but also has potential application value in the toughening of other polymer materials.

Description

Technical Field

[0001] The invention belongs to the technical field of functional polymer material modification, and particularly relates to a method for coordinating and toughening polyamide based on aliphatic and aromatic supramolecular segments. Background Art

[0002] The information disclosed in the background of the invention is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Polyamides, as an important engineering plastic, are widely used in modern industry due to their excellent comprehensive properties. Based on the structure of the repeating units in the polymer chain, polyamides can be divided into three types: aliphatic polyamides, aromatic polyamides, and semi-aromatic polyamides. Aliphatic polyamides, containing only aliphatic structures in their backbone, are lightweight, wear-resistant, easy to dye, and process, but they are difficult to use in high-temperature environments. In contrast, aromatic polyamides, due to the abundance of benzene rings in their backbone, possess excellent mechanical and thermal properties. However, their rigid structure makes them insoluble in common solvents, and their melting point is often close to their decomposition temperature, making processing difficult and limiting their application. Semi-aromatic polyamides combine the excellent properties of aromatic polyamides with the good processing properties of aliphatic polyamides. In recent years, they have been widely used in electronics, the automotive industry, equipment manufacturing, and other fields. However, semi-aromatic and aromatic polyamides exhibit strong intermolecular or intramolecular stacking, resulting in dense and regular polymer chain arrangement and prone to brittle fracture. To promote their engineering applications, toughening polyamides has proven to be a difficult task. Summary of the Invention

[0004] To address the aforementioned technical issues, the present invention provides a method for coordinating the toughening of polyamides using aliphatic and aromatic supramolecular segments. This method, by introducing rigid-flexible supramolecular segments into a polyamide system containing aromatic and aliphatic supramolecular segments, disrupts the regularity of the polymer chains and modulates stress distribution within the polymer. Simultaneously, appropriate supramolecular interactions act as sacrificial bonds to dissipate energy, thereby improving the toughness of the material.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for synergistically toughening polyamide using aliphatic and aromatic supramolecular segments, comprising the following steps:

[0007] Mixing aliphatic hydrazide and aromatic amine monomers with an organic solvent to prepare a solution containing rigid-flexible supramolecular monomers;

[0008] An acyl chloride compound is added to the solution containing the rigid-flexible supramolecular monomer, and condensed under ice bath conditions to obtain supramolecular polyamide.

[0009] Furthermore, the aliphatic hydrazide is: adipic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, etc.

[0010] Furthermore, the aromatic amine monomer is: 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-ethylenediphenylamine, and the like.

[0011] Furthermore, the acyl chloride compound is terephthaloyl chloride, isophthaloyl chloride, 4,4'-oxydibenzoyl chloride, etc.

[0012] Furthermore, the usage ratio of the aliphatic hydrazide, the aromatic amine monomer, and the acyl chloride compound is: m (0.25-0.5): n (0.5-0.75): m+n.

[0013] Furthermore, the organic solvent is selected from N-methylpyrrolidone and N,N-dimethylacetamide.

[0014] Furthermore, the condensation time is 4-8 hours.

[0015] In a second aspect, the present invention provides a supramolecular polyamide material prepared by the above method.

[0016] The third aspect of the present invention provides the application of the supramolecular polyamide material in the field of high toughness and solvent-resistant materials, which also has potential application value in guiding the design and development of other strong and tough polymer materials.

[0017] Introducing appropriate supramolecular interactions into polymers can enhance the energy dissipation capacity of the material and improve the toughness of the material. The supramolecular cross-linked network can be used to modify the microphase structure of the copolymer, while acting as a sacrificial link to dissipate energy, thereby making the synthetic material tougher. Through research, it was found that supramolecular fragments were incorporated into polyurethane to successfully balance its mechanical properties, chemical resistance and processability. On this basis, the present invention proposes to appropriately introduce supramolecular interactions into polyamides as sacrificial bonds to consume energy, while also disrupting the regularity of the polymer chain and regulating the stress distribution in the polymer, thereby improving the toughness of the material. The present invention constructs a polyamide system containing aromatic and aliphatic supramolecular segments, and utilizes the mismatched interactions between rigid and flexible supramolecular segments to regulate the crystallinity, microphase separation and energy dissipation of the polymer to improve the mechanical properties of the material.

[0018] The present invention has the following beneficial effects:

[0019] (1) The present invention achieves toughening of polyamide based on the coordinated toughening of aliphatic and aromatic supramolecular segments.

[0020] (2) The supramolecular polyamide of the present invention can precisely control the crystallinity, microphase separation structure and energy dissipation capacity of the polymer by adjusting the mismatched supramolecular interactions between rigid and flexible supramolecular segments.

[0021] (3) The supramolecular polyamide of the present invention has simple raw materials, a simple preparation process, low cost, low requirements on reaction conditions and equipment, strong practicality, and good application prospects.

[0022] (4) The rigid-flexible supramolecular toughening strategy provided by the present invention is not limited to the polyamide system, but also has potential application value in toughening other polymer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 Schematic diagram of the synthesis of supramolecular polyamide TAOx of the present invention.

[0025] Figure 2 Images of supramolecular polyamides TAOx with different ratios prepared in this invention; We synthesized five supramolecular polyamides containing aliphatic ADH and / or aromatic ODA segments using TPC low-temperature solution polycondensation: TAO0 contains only ADH supramolecular segments, TAO1 contains only ODA supramolecular segments, and TAO 0.25 、TAO 0.5 and TAO 0.75 Contains both ADH and ODA fragments (n ADH :n ODA 3:1, 1:1 and 1:3 respectively). As shown in the figure, TAO0 is brittle and cannot form a whole film, while TAO1 forms a wrinkled film with poor transparency. In contrast, supramolecular polyamide containing both ADH and ODA segments can form a whole or even a film. 0.25 and TAO 0.5 The transparency is the best.

[0026] Figure 3 The SEM images of supramolecular polyamides TAOx prepared in different proportions according to the present invention are shown in the figure. As shown in the figure, TAO0 containing only ADH segments presents a striped structure. As the ODA content in the polyamide increases, the morphology gradually changes from a striped structure to a spherical structure.

[0027] Figure 4Figure 1 shows the stress-strain curve (a), toughness (b), and Young's modulus (c) of the supramolecular polyamide TAOx prepared in the present invention. As shown in the figure, with the increase of the ODA:ADH ratio, the toughness of TAOx first increases and then decreases. When the ODA:ADH molar ratio is 1:1, the maximum toughness of TAOx is 31.2 MJ m -3 ( Figure 4 a,b). TAO 0.5 The rigid-flexible supramolecular interaction gives it a high energy dissipation capacity, which makes the prepared polyamide have high toughness. However, compared with the other four polyamides, TAO 0.5 The Young's modulus is the smallest, which is 575.1MPa ( Figure 4 c). DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0029] Example 1: Preparation of supramolecular polyamide with 0% 4,4'-diaminodiphenyl ether monomer content

[0030] 90 mL of NMP was added to a 250 mL three-necked round bottom flask. 3.20 g of adipic acid dihydrazide was added to the reaction vessel under ice bath conditions and magnetic stirring was performed for 30 min. Then, 3.70 g of terephthaloyl chloride was added to the reaction system and the mixture was stirred at 1500 rmin. -1 The reaction was continued for 4 h at a stirring speed of .5 ℃. After the reaction was completed, the obtained solution was poured into a glass culture dish and vacuum dried at 80 ° C for 16 h to obtain supramolecular polyamide TAO0. The preparation process is as follows Figure 1 shown.

[0031] Example 2: Preparation of supramolecular polyamide with 25% 4,4'-diaminodiphenyl ether monomer content

[0032] 90 mL of NMP was added to a 250 mL three-necked round bottom flask. Under ice bath conditions, 2.40 g of adipic acid dihydrazide and 0.92 g of 4,4'-diaminodiphenyl ether were added to the reaction vessel and magnetically stirred for 30 min. Then, 3.7 g of terephthaloyl chloride was added to the reaction system and the mixture was stirred at 1500 r min. -1 After the reaction, the obtained solution was poured into a glass culture dish and vacuum dried at 80 ° C for 16 hours to obtain supramolecular polyamide TAO. 0.25 The preparation process is as follows. Figure 1 shown.

[0033] Example 3: Preparation of supramolecular polyamide with 50% 4,4'-diaminodiphenyl ether monomer content

[0034] 90 mL of NMP was added to a 250 mL three-necked round-bottom flask. 1.60 g of adipic acid dihydrazide and 1.84 g of 4,4'-diaminodiphenyl ether were added to the reaction vessel under ice bath conditions and magnetically stirred for 30 min. Then, 3.7 g of terephthaloyl chloride was added to the reaction system and the mixture was stirred at 1500 r min. -1 After the reaction, the obtained solution was poured into a glass culture dish and vacuum dried at 80 ° C for 16 hours to obtain supramolecular polyamide TAO. 0.5 The preparation process is as follows. Figure 1 shown.

[0035] Example 4: Preparation of supramolecular polyamide with 75% 4,4'-diaminodiphenyl ether monomer content

[0036] 90 mL of NMP was added to a 250 mL three-necked round bottom flask. Under ice bath conditions, 0.80 g of adipic acid dihydrazide and 2.76 g of 4,4'-diaminodiphenyl ether were added to the reaction vessel and magnetically stirred for 30 min. Then, 3.7 g of terephthaloyl chloride was added to the reaction system and the mixture was stirred at 1500 r min. -1 After the reaction, the obtained solution was poured into a glass culture dish and vacuum dried at 80 ° C for 16 hours to obtain supramolecular polyamide TAO. 0.75 The preparation process is as follows. Figure 1 shown.

[0037] Example 5: Preparation of supramolecular polyamide containing 100% 4,4'-diaminodiphenyl ether monomer

[0038] 90 mL of NMP was added to a 250 mL three-necked round bottom flask. Under ice bath conditions, 3.68 g of 4,4'-diaminodiphenyl ether was added to the reaction vessel and magnetically stirred for 30 min. Then, 3.7 g of terephthaloyl chloride was added to the reaction system and the mixture was stirred at 1500 r min. -1 The reaction was continued for 4 h at a stirring speed of .5 ℃. After the reaction was completed, the obtained solution was poured into a glass culture dish and vacuum dried at 80 ° C for 16 h to obtain supramolecular polyamide TAO1. Figure 1 shown.

[0039] Figure 2 The present invention prepares images of supramolecular polyamides TAOx with different proportions; the present invention synthesizes five supramolecular polyamides containing aliphatic ADH and / or aromatic ODA segments by TPC low-temperature solution polycondensation: TAO0 contains only ADH supramolecular segments, TAO1 contains only ODA supramolecular segments, TAO0.25 、TAO 0.5 and TAO 0.75 Contains both ADH and ODA fragments (n ADH :n ODA 3:1, 1:1 and 1:3 respectively). As shown in the figure, TAO0 is brittle and cannot form a whole film, while TAO1 forms a wrinkled film with poor transparency. In contrast, supramolecular polyamide containing both ADH and ODA segments can form a whole or even a film. 0.25 and TAO 0.5 The transparency is the best.

[0040] Figure 3 Figure 2 is the SEM image of supramolecular polyamide TAOx with different proportions prepared by the present invention. Figure 3 As shown in Figure 3, TAO0 containing only ADH segments presents a stripe-like structure. As the ODA content in polyamide increases, the morphology gradually changes from a stripe-like structure to a spherical structure.

[0041] Figure 4 Figure 2 is the stress-strain curve (a), toughness (b) and Young's modulus (c) of the supramolecular polyamide TAOx prepared in the present invention. Figure 4 As shown in Figure 2, with the increase of the ODA:ADH ratio, the toughness of TAOx first increases and then decreases. When the ODA:ADH molar ratio is 1:1, the maximum toughness of TAOx is 31.2 MJ m -3 ( Figure 4 a,b). TAO 0.5 The rigid-flexible supramolecular interaction gives it a high energy dissipation capacity, which makes the prepared polyamide have high toughness. However, compared with the other four polyamides, TAO 0.5 The Young's modulus is the smallest, which is 575.1MPa ( Figure 4 c).

[0042] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for synergistically toughening polyamide using aliphatic and aromatic supramolecular segments, characterized in that: The steps include: Mixing aliphatic hydrazide and aromatic amine monomers with an organic solvent to prepare a solution containing rigid-flexible supramolecular monomers; adding an acyl chloride compound to the solution containing the rigid-flexible supramolecular monomer, and condensing the mixture under ice bath conditions to obtain supramolecular polyamide; The ratio of the amount of aliphatic hydrazide, aromatic amine monomer and acyl chloride compound is m:n:m+n; The m is 0.25 to 0.5; the n is 0.25 to 0.5; The aliphatic hydrazide is selected from one or more of adipic acid dihydrazide, suberic acid dihydrazide, and azelaic acid dihydrazide; The aromatic amine monomer is selected from one or more of 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, and 4,4'-ethylenediphenylamine.

2. The method according to claim 1, characterized in that The acyl chloride compound is selected from one or more of terephthaloyl chloride, isophthaloyl chloride, and 4,4'-oxydibenzoyl chloride.

3. The method according to claim 1, characterized in that The organic solvent is selected from one or both of N-methylpyrrolidone and N,N-dimethylacetamide.

4. The method according to claim 1, characterized in that The condensation time is 4-8h.

5. The method according to claim 1, characterized in that: The stirring speed is 1000-1500rpm.

6. The supramolecular polyamide prepared according to the method according to any one of claims 1 to 5.

7. Use of the supramolecular polyamide according to claim 6 in the field of high toughness and solvent-resistant materials.

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