Preparation method of photo-thermal dual-response self-repairing transparent nylon material

Abstract

The application relates to a preparation method of a photothermal dual-response self-repairing transparent nylon material, characterized by the following steps: taking sebacic acid, decanediamine, bis (p-aminocyclohexyl) methane and N-methyl piperazine amide as comonomers, taking acetic acid as a molecular weight regulator, preparing a transparent nylon resin containing secondary amino groups in side chains through a melt polycondensation reaction, and adding the transparent nylon resin particles and a dynamic crosslinking agent 1,8-anthracene di (4-maleimide phenyl) into an organic solvent to obtain the photothermal dual-response self-repairing transparent nylon material. The application can bypass the restriction of high-temperature melt processing on a dynamic chemical system, and can precisely and uniformly introduce stable and efficient multiple intelligent response functions into the transparent nylon under mild conditions.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a method for preparing a photothermal dual-response self-healing transparent nylon material. Background Technology

[0002] Transparent nylon, due to its excellent mechanical strength, chemical resistance, heat resistance, and high transparency, is widely used in optical lenses, electronic device windows, instrument panels, and high-end packaging materials. However, like most polymer materials, transparent nylon is prone to micro-damage such as microcracks and scratches during processing or use. These damages become stress concentration points, accelerating material aging and failure, and significantly impairing its optical and mechanical properties. To address this issue, endowing materials with self-healing capabilities has become an ideal strategy. Among these, intrinsic self-healing systems based on dynamic covalent bonds, such as the Diels-Alder (DA) reaction, have attracted widespread attention due to their ability to repair themselves multiple times. However, successfully introducing such intelligent systems into high-performance engineering plastics like transparent nylon faces significant challenges: Processing temperature conflict: The ideal reversible temperature window (typically 90-130°C) for dynamic covalent bonds (such as the DA reaction of furan / maleimide) is much lower than the typical melt processing temperature of transparent nylon (typically >220°C). During high-temperature melt blending or injection molding, dynamic crosslinking agents may decompose, undergo side reactions (such as oxidation, thermal dimerization), or undergo undesirable chemical reactions with the polymer matrix, causing the dynamic function to fail during the processing stage.

[0003] Dispersion and compatibility issues: Most dynamic crosslinking agents are solid small molecules with poor compatibility with nylon melt. It is difficult to achieve uniform dispersion at the molecular level during the short melt mixing process, and phase separation is very likely to occur, forming micro-regions with a size larger than the wavelength of light, resulting in increased haze and decreased transparency of the material.

[0004] Functional integration difficulties: The complex molecular structure introduced to achieve multiple responses such as light and heat has different functional groups with varying sensitivities to processing conditions, making it difficult to retain all functions simultaneously under harsh processing environments.

[0005] Therefore, there is an urgent need in this field for a new technological approach that can bypass the limitations of high-temperature melting processing on dynamic chemical systems and introduce stable and efficient multiple intelligent response functions into transparent nylon precisely and uniformly under mild conditions. Summary of the Invention

[0006] To address the problems mentioned in the background art, the present invention aims to provide a method for preparing a photothermal dual-response self-healing transparent nylon material.

[0007] The technical solution to the problem solved by this invention is: a method for preparing a photothermal dual-response self-healing transparent nylon material, comprising the following steps: A transparent nylon resin with secondary amino groups in its side chains was prepared by melt polycondensation using sebacic acid, sebacic diamine, bis(p-aminocyclohexyl)methane (PACM) and N-methylpiperazinamide (N-MPA) as comonomers and acetic acid as a molecular weight regulator.

[0008] Transparent nylon resin particles and a dual dynamic crosslinking agent, 1,8-anthracene di(4-maleimidebenzene) (An-MI), were added to an organic solvent to obtain functionalized PA-SeC resin.

[0009] Furthermore, the amount of molecular weight regulator added is 0.5-1.0% of the total monomer molars. Furthermore, the molar percentages of each monomer are as follows: sebacic acid 45-48%, sebacic diamine 27-33%, PACM 18-24%, N-MPA 2-4%; The mass-to-volume ratio of the transparent nylon resin to the organic solvent is 1 g : (10-20) mL; the amount of An-MI added is 2.0-5.0% of the mass of the transparent nylon resin. The organic solvent is preferably N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), or dimethyl sulfoxide (DMSO). An-MI molecules diffuse into the interior and surface of the swollen PA-SeC resin particles. Under mild conditions, the maleimide groups (C=C) at both ends undergo efficient Michael addition reactions with the secondary amino groups (-NH-CH3) on the PA-SeC side chains, forming stable covalent bonds. This firmly grafts the photothermal-responsive An-MI molecules onto the nylon molecular chains as pendant side chains. During subsequent melt molding, these An-MI-grafted molecular chains fully diffuse and entangle under heat and shear, forming an effective topological entanglement network at the particle interface through physical interactions such as the potential π-π stacking of anthracene groups. When the material is damaged during use and subjected to external stimuli (such as heat or light), this network can achieve macroscopic self-repair, shape memory, and photochromic functions through molecular chain movement, photodimerization / dissociation of anthracene groups, and possible Michael addition / reverse reactions.

[0010] The beneficial effects of this invention are as follows: This invention introduces a dual dynamic crosslinking agent into the polymer backbone, maintaining the high transparency and mechanical properties of the matrix, achieving efficient and gentle self-healing capabilities, and integrating significant photoresponsive intelligent properties. Detailed Implementation

[0011] To further illustrate the present invention, specific embodiments are provided below. It should be understood that these embodiments are only for aiding understanding of the present invention and do not constitute a limitation on the scope of the invention. Furthermore, it should be understood that after studying the content of this invention, those skilled in the art can make various improvements or adjustments, and these modifications should also be considered within the protection scope of this invention.

[0012] Before introducing specific embodiments of the present invention, it should be clarified that the scope of protection of the present invention is not limited to the specific embodiments described below. Furthermore, the terminology used in this invention is for the convenience of describing specific embodiments and is not intended to limit the scope of the invention. Unless otherwise defined, all technical terms in this invention should be interpreted in accordance with the common understanding of those skilled in the art. For experimental methods not specifically listed in the embodiments, they should generally be operated under conventional conditions or the recommended conditions of the equipment manufacturer. In addition to the specific methods, equipment, and materials used in the embodiments, the present invention can also be implemented using existing technical solutions that are similar to or equivalent to the methods, equipment, and materials described in the embodiments.

[0013] Example 1: (1) Synthesis of side-chain secondary amino transparent nylon (PA-SeC) Sebacic acid, sebacic acid, PACM, N-methylpiperazinamide (N-MPA), and acetic acid in a molar ratio of 46.5:30.5:21.5:1.5:0.5 were added to a high-pressure polymerization reactor. The air inside the reactor was purged three times with high-purity nitrogen. The temperature was raised to 210°C, and the pressure was 1.5-1.8 MPa. The reaction was carried out at this pressure for 2-3 hours. The pressure was then reduced at a rate of 1.5 MPa / 10 min. The reaction was carried out at atmospheric pressure for 20 min, followed by nitrogen venting for 60 min. The reaction temperature was 255-260°C at this point. After the reaction was completed, the pressure was increased to 0.6-0.7 MPa, and the polymer melt was extruded and pelletized to obtain PA-SeC resin granules.

[0014] (2) Standard functionalization processing In a three-necked flask, resin particles and An-MI were added in a mass ratio of 100:3, and 1500 ml of DMF was poured in. The mixture was stirred at 100°C for 6 hours. After filtration, the mixture was washed three times with fresh DMF and dried under vacuum at 60°C for 36 hours to obtain a photothermal dual-response self-healing transparent nylon material.

[0015] Example 2: The procedure is the same as in Example 1, except that resin particles and An-MI are added at a mass ratio of 100:5.

[0016] Example 3: The procedure is the same as in Example 1, except that resin particles and An-MI are added at a mass ratio of 100:2.

[0017] Example 4 Sebacic acid, sebacic acid, PACM, N-methylpiperazinamide (N-MPA), and acetic acid in a molar ratio of 48:33:24:4:0.55 were added to a high-pressure polymerization reactor. The air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure was 1.5-1.8 MPa. The reaction was carried out at this pressure for 2-3 hours. The pressure was then reduced at a rate of 1.5 MPa / 10 min. The reaction was carried out at atmospheric pressure for 20 min, followed by nitrogen venting for 60 min. The reaction temperature was 255-260℃ at this point. After the reaction was completed, the pressure was increased to 0.6-0.7 MPa, and the polymer melt was extruded and pelletized to obtain PA-SeC resin particles.

[0018] (2) Standard functionalization processing In a three-necked flask, resin particles and An-MI were added in a mass ratio of 100:5, and 2000 mL of NMP was poured in. The mixture was stirred at 100 °C for 6 hours. After filtration, the mixture was washed three times with fresh NMP and dried under vacuum at 60 °C for 36 hours to obtain a photothermal dual-response self-healing transparent nylon material.

[0019] Example 5 Sebacic acid, sebacic acid, PACM, N-methylpiperazinamide (N-MPA), and acetic acid in a molar ratio of 45:27:18:2:0.46 were added to a high-pressure polymerization reactor. The air inside the reactor was purged three times with high-purity nitrogen. The temperature was raised to 210°C, and the pressure was 1.5-1.8 MPa. The reaction was carried out at this pressure for 2-3 hours. The pressure was then reduced at a rate of 1.5 MPa / 10 min. The reaction was carried out at atmospheric pressure for 20 min, followed by nitrogen venting for 60 min. The reaction temperature was 255-260°C at this point. After the reaction was completed, the pressure was increased to 0.6-0.7 MPa, and the polymer melt was extruded and pelletized to obtain PA-SeC resin particles.

[0020] (2) Standard functionalization processing In a three-necked flask, resin particles and An-MI with a mass ratio of 100:2 were added, and 1800 mL of DMSO was poured in. The mixture was stirred at 100 °C for 6 hours. After filtration, the mixture was washed three times with fresh DMSO and dried under vacuum at 60 °C for 36 hours to obtain a photothermal dual-response self-healing transparent nylon material.

[0021] Example 6: The procedure is the same as in Example 1, except that the solvent DMF is replaced with an equal volume of N-methylpyrrolidone (NMP).

[0022] Comparative Example 1: Unfunctionalized matrix The procedure is the same as in Example 1, but An-MI is not added in the functionalization step. Instead, the PA-SeC resin is immersed, washed, and dried in DMF under the same conditions before injection molding.

[0023] Comparative Example 2: Melt Blending Method Resin granules and An-MI at a mass ratio of 100:3 were physically premixed in a high-speed mixer for 3 minutes; the premix was then melt-blended and granulated using a twin-screw extruder. The extrusion process was carried out at a temperature of 210℃ throughout.

[0024] Testing and Characterization Performance tests were performed on all the specimens prepared in the examples and comparative examples, and the results are summarized in the table below.

[0025] Table 1: Overall Performance Test Results

[0026] Results Analysis and Conclusions Comparative Example 2 exhibited poor overall performance. This indicates that An-MI has extremely poor compatibility with the matrix in the high-temperature molten state, resulting in severe phase separation, and An-MI itself may have undergone thermal decomposition or side reactions. Its self-healing efficiency and photoresponsiveness are also very weak.

[0027] As the An-MI dosage increased from 2.0% to 5.0%, the crosslinking density increased. Tensile strength and heat distortion temperature increased slightly with increasing dosage, but elongation at break and impact toughness decreased accordingly. Light transmittance decreased slightly, and haze increased slightly, but remained at an excellent level. Self-healing efficiency remained high (85%-90%) within the 2.0%-5.0% range. Example 2 showed the highest efficiency but poorer toughness; Example 3 showed the best balance. This demonstrates that the objectives of this invention can be achieved with An-MI dosages within the range of 2.0%-5.0%, providing flexibility for adjusting material properties.

[0028] The effect of using NMP as a solvent (Example 6) is almost equivalent to that of using DMF (Example), indicating that the present invention has good universality for solvent systems.

[0029] The preferred embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A method for preparing a photothermal dual-response self-healing transparent nylon material, characterized in that: A transparent nylon resin with secondary amino groups in its side chains was prepared by melt polycondensation using sebacic acid, decanediamine, bis(p-aminocyclohexyl)methane, and N-methylpiperazinamide as comonomers and acetic acid as a molecular weight regulator. The melt polycondensation reaction was carried out in a high-pressure polymerization reactor. First, the air in the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210°C, and the pressure was 1.5-1.8 MPa. The reaction was carried out at this pressure for 2-3 hours. The pressure was then reduced at a rate of 1.5 MPa / 10 min. The reaction was carried out at atmospheric pressure for 20 min, followed by nitrogen venting for 60 min. The reaction temperature was 255-260°C. After the reaction was completed, the pressure was increased to 0.6-0.7 MPa. The transparent nylon resin particles and the dual dynamic crosslinking agent 1,8-anthracene di(4-maleimidebenzene) were added to an organic solvent to obtain a photothermal dual-response self-healing transparent nylon material.

2. The method for preparing a photothermal dual-response self-healing transparent nylon material according to claim 1, characterized in that: The molar percentages of the comonomers are: sebacic acid 45-48%, sebacic diamine 27-33%, bis(p-aminocyclohexyl)methane 18-24%, and N-methylpiperazinamide 2-4%.

3. The method for preparing a photothermal dual-response self-healing transparent nylon material according to claim 1, characterized in that: The amount of molecular weight regulator added is 0.5-1.0% of the total number of monomer moles.

4. The method for preparing a photothermal dual-response self-healing transparent nylon material according to claim 1, characterized in that: The organic solvent is N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide.

5. The method for preparing a photothermal dual-response self-healing transparent nylon material according to claim 1, characterized in that: The mass-to-volume ratio of the transparent nylon resin to the organic solvent is 1 g:(10-20) mL; the amount of 1,8-anthracene di(4-maleimidebenzene) added is 2.0-5.0% of the mass of the transparent nylon resin.

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