An environmentally-friendly polymer material capable of regulating dynamic network and a preparation and closed-loop recycling method thereof
By regulating the dynamic network structure through thiol-ene click reaction and the introduction of vinylamine ester bonds, the problem of balancing recyclability and mechanical properties of dynamic reversible cross-linked network materials is solved, realizing efficient and environmentally friendly material preparation and recycling, which is applicable to fields such as construction, packaging, medical, and electronics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-10
- Publication Date
- 2026-03-31
AI Technical Summary
Existing dynamic reversible cross-linked network materials present a challenge in balancing processing recyclability and mechanical properties, and traditional synthesis methods are demanding, making it difficult to achieve efficient large-scale production.
A thiol-ene click reaction was used to prepare acetoacetate polymers, and vinylamine ester bonds were introduced. By adjusting the crosslinking nodes and branching structures, tunable dynamic network polymer materials were prepared, which are suitable for large-scale production.
It has enabled the preparation of high-performance, highly recyclable, and environmentally friendly polymer materials under mild conditions, which are applicable to multiple fields, reduce production costs and safety risks, and meet different application needs.
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Figure CN119798653B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials and relates to an environmentally friendly polymer material with a controllable dynamic network and its preparation and closed-loop recycling method, particularly to a closed-loop recyclable material with high mechanical properties, recyclability and degradability. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] With the widespread dissemination of the concept of sustainable development and increasingly stringent environmental regulations, the demand for recyclable and biodegradable high-performance polymers in the field of materials science is constantly increasing. However, traditional thermosetting polymers, due to their highly cross-linked permanent network structure, exhibit excellent strength and durability in mechanical properties, but because of these irreversible cross-linking points, they are difficult to recycle after use, causing serious environmental pollution problems.
[0004] In recent years, a class of polymer materials with dynamic reversible cross-linked network properties has gradually emerged. Under specific external conditions (such as heat or catalysts), the dynamic chemical bonds in these materials can break and recombine, thus enabling the materials to maintain high mechanical properties while also possessing processability and repairability, providing a new technical path for the closed-loop recycling of high-performance materials. However, existing dynamic reversible cross-linked network materials still face a certain balance challenge between processability, recyclability, and mechanical properties: when the cross-linking strength is high, mechanical properties can be guaranteed, but the dynamic cross-linking reaction rate is usually slow, resulting in inefficient recycling and reprocessing processes; when the cross-linking strength is reduced to improve recycling efficiency, the overall mechanical properties of the material are difficult to meet application requirements. In addition, some current methods often only adjust the spacing between cross-linking points by increasing or decreasing the molecular weight to control the dynamic network. Although this can affect the relaxation performance of the network to some extent, it has limited impact on the activation energy of dynamic bonds because it does not essentially change the topological structure of the dynamic network, and cannot significantly improve processing performance while maintaining high mechanical properties. At the same time, efficient synthesis and large-scale production of materials are also crucial for large-scale industrial applications. If the reaction conditions are too harsh (such as high temperature, high pressure or extreme acidity or alkalinity), it will not only increase production costs and energy consumption, but also increase safety risks, which is not conducive to large-scale promotion. Summary of the Invention
[0005] To address the aforementioned problems, this invention provides an environmentally friendly polymer material with a tunable dynamic network and its preparation and closed-loop recycling method. Acetylacetate polymers with different branching structures are prepared via a thiol-ene click reaction to adjust the number of crosslinking nodes and branches in the network, thereby endowing the material with a tunable network topology and effectively controlling its dynamic and mechanical properties. Simultaneously, the introduction of vinylamine ester bonds into the polymer network provides a feasible approach for achieving closed-loop recycling of this material.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] In a first aspect, the present invention provides a method for preparing an environmentally friendly polymer material with a tunable dynamic network, comprising:
[0008] Photopolymerization of acetoacetate with thiols of different functionalities in a solvent yields multifunctional acetoacetate polymers.
[0009] The acetoacetate polymer and the polyamine monomer were crosslinked in a solvent to obtain a prepolymer;
[0010] After curing the prepolymer, annealing is performed to obtain the dynamic network polymer material film.
[0011] The thiol-ene click reaction is a highly efficient, rapid chemical reaction with high selectivity for side reactions, making it ideal for synthesizing polymers with dynamic network properties. Its main advantages include: mild reaction conditions: The thiol-ene reaction can be carried out at relatively low temperatures or under catalytic conditions, without the need for high pressure or strong acid / base environments, making it suitable for large-scale production. High selectivity: The thiol-ene click reaction can generate stable covalent bond structures with minimal side reactions, ensuring the stability of the material structure and the uniformity of the crosslinked network. Therefore, the ene click reaction can effectively prepare ideal acetoacetate monomers.
[0012] Based on the above principles, this invention prepares acetoacetate polymers through a carefully designed olefin click reaction system and introduces reversible vinylamine ester bonds to obtain crosslinked polymers with different mechanical and thermodynamic properties. The introduction of multifunctional monomers not only makes the mechanical properties of the crosslinked network tunable but also provides conditions for the closed-loop recycling and upgrading of the polymer, ensuring that the material possesses both high performance and environmental friendliness, thereby meeting the needs of various application scenarios for recyclable, biodegradable, and high-performance polymer materials. In some embodiments, the acetoacetate olefin is ethylene glycol acetoacetate methacrylate or allyl acetoacetate.
[0013] In some embodiments, the thiol is selected from one of bis(3-mercaptopropionic acid) ethylene glycol, trimethylolpropane tri(3-mercaptopropionic acid) ester, pentaerythritol tetra(3-mercaptopropionic acid) ester, ethylenedithiol, and hexanedithiol.
[0014] In some embodiments, the molar ratio of acetoacetate to thiol is 1:1-4.
[0015] In some embodiments, the initiator of the photopolymerization reaction is 2-hydroxy-2-methylphenylacetone or phenyldibenzothiophene, and the amount added is 0.4%-0.6% of the total mass of the monomers.
[0016] In some embodiments, the polyamine monomer is selected from at least one of isophorone diamine, hexamethylenediamine, and tris(2-aminoethyl)amine.
[0017] In some embodiments, the molar ratio of the acetoacetate polymer to the amine group is 1:1 to 1.5; the dynamic performance of the network can be adjusted according to the proportion provided by the amine group.
[0018] In some embodiments, the annealing temperature is 120°C-130°C and the time is 6-8 hours.
[0019] More specifically, including:
[0020] Step 1: Add acetoacetate and thiol with a C=C:SH molar ratio of 1:1 to a flask equipped with a magnetic stirrer, then add 0.5-2 wt% of the photoinitiator 2-hydroxy-2-methylphenylacetone, stir at 20-60°C, and irradiate the reaction mixture with a UV lamp (365 nm, 1200 uw / cm2) for 24 hours to obtain the product acetoacetate monomer.
[0021] The second step involves taking acetoacetate monomer and polyamine monomer in a molar ratio of 1:1.2 to 1:1.5 and adding them to a 100 mL three-necked flask equipped with a reflux condenser, an electric stirrer, and a thermometer. 20 mL of DMF is added, and the mixture is reacted at 20–50 °C for 4 hours. The mixture is then cooled to ambient temperature to obtain the prepolymer.
[0022] The third step involves transferring the prepolymer into a polytetrafluoroethylene mold, placing it in an 80°C oven for 24 hours to remove DMF, and then curing it in a 120°C oven for 4 hours to obtain a dynamic network polymer film containing vinyl amine ester bonds. To ensure the film has good mechanical properties and network structure, annealing can be performed at 120°C for 6-8 hours.
[0023] The fourth step is the recycling and upgrading of the polymer. The obtained polymer is chopped and placed in a three-necked flask. A 0.1 mol / L solution of hydrochloric acid and tetrahydrofuran is added. The mixture is filtered to obtain a solution containing acetoacetate and an amine salt. The solution containing acetoacetate is neutralized and purified to obtain the acetoacetate polymer monomer. The amine salt can be reduced back to an amine using a methanol solution of KOH.
[0024] A second aspect of the present invention provides an environmentally friendly polymer material with a tunable dynamic network prepared by the above method.
[0025] This invention aims to obtain environmentally friendly polymer materials that combine high mechanical properties with excellent recyclability by introducing an easily controllable dynamic cross-linked network structure and a mild and efficient click chemistry reaction pathway. At the material design level, by rationally selecting and adjusting the thiol-ene reaction system and the type and number of reversible cross-linking units, the activation energy of dynamic bonds can be effectively reduced, and the network topology can be precisely controlled, thereby achieving a good balance between closed-loop recycling and controllable mechanical properties. Simultaneously, the preparation process of this invention is mild and simplified, facilitating industrial production and providing high-value-added, environmentally sustainable polymer materials for multiple fields while reducing resource and energy consumption. Through the above technical means and ideas, a feasible and efficient solution can be provided to address the current challenge of recycling thermosetting polymer materials, and new ideas and support can be offered for the development of sustainable materials and a circular economy.
[0026] A third aspect of the present invention provides a closed-loop recycling method for the above-mentioned environmentally friendly polymer material with adjustable dynamic network, comprising:
[0027] After chopping up the polymer material containing vinylamine ester bonds, add a tetrahydrofuran solution of 0.1-0.15 mol / L hydrochloric acid and filter to obtain a solution containing acetoacetate and amine salt;
[0028] The solution containing acetoacetate was neutralized and purified to obtain acetoacetate polymer;
[0029] The amine salt is reduced back to an amine using a methanol solution of KOH, thus obtaining the final product.
[0030] A fourth aspect of the present invention provides the application of the above-mentioned environmentally friendly polymer material with adjustable dynamic network in the fields of construction, transportation and packaging, optics and aerospace.
[0031] Beneficial effects of the present invention
[0032] (1) Based on the dynamic reversible properties of thiol-ene click reaction and vinylamine ester bond, this invention enables the breaking and recombination of crosslinking points under appropriate external conditions, allowing for closed-loop recycling of the material. Compared with traditional non-recyclable thermosetting materials, the material of this invention can effectively reduce resource consumption and waste generation, and has significant environmental advantages.
[0033] (2) The preparation method of this invention allows for alteration of the network topology by adjusting the functionality of thiols and amines. This enables control over two different types of crosslinking nodes and the number of branches at various crosslinking points, thereby flexibly adjusting the material's dynamic properties, dynamic bond activation energy, mechanical properties, and repairability to meet the specific needs of different applications. The flexibility of the formulation design makes this material highly adaptable, allowing for adjustment of its properties according to the needs of different fields, and making it widely applicable to multiple industries such as construction, packaging, medical, and electronics. The preparation method of this invention can alter the network topology by adjusting the functionality of thiols and amines, thereby flexibly controlling two different types of crosslinking nodes and the number of branches at various crosslinking points. This further allows for adjustment of the material's dynamic properties, dynamic bond activation energy, mechanical properties, and repairability to meet the specific needs of various application scenarios. Due to the high flexibility of the formulation design, this material can be well applied in multiple industries such as construction, packaging, medical, and electronics, demonstrating extremely high adaptability.
[0034] (3) The thiol-alkene click reaction has mild reaction conditions and does not require harsh conditions such as strong acids, strong bases or high pressure, which facilitates large-scale production and reduces energy consumption and safety risks in the production process. The preparation process of the material of this invention is simple and low-cost, suitable for industrial application, and can be rapidly promoted on existing production facilities, driving the market application of sustainable, high-performance materials. Attached Figure Description
[0035] The accompanying drawings, which form part of this specification, are intended to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are for illustrative purposes only and do not constitute any undue limitation of the invention.
[0036] Figure 1 The image shows the 1H NMR spectrum of the trifunctional acetoacetate monomer prepared in Example 1 of this invention.
[0037] Figure 2 This is a schematic diagram of the closed-loop recovery of the dynamic network polymer material containing vinylamine ester bonds prepared in Example 1 of the present invention.
[0038] Figure 3 This is a comparison of the mechanical properties of the dynamic network polymer material containing vinylamine ester bonds prepared in Example 1 of the present invention before and after solvent recovery. Detailed Implementation
[0039] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0040] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.
[0041] Example 1:
[0042] first step:
[0043] In a flask equipped with a magnetic stirrer, allyl acetoacetate and trimethylolpropane tris(3-mercaptopropionate) were added in a C=C:SH group molar ratio of 1:1, followed by 0.5 wt% of the total mass of the two as a photoinitiator, 2-hydroxy-2-methylphenylpropanone. The mixture was stirred at 20°C and tested with a wavelength of 365 nm and an intensity of approximately 1200 μW / cm². 2 Irradiation with a UV lamp for 24 hours yielded the product, acetoacetate trimer.
[0044] Step Two:
[0045] A 1:1.2 molar ratio of acetoacetate trimer and tris(2-aminoethyl)amine (TREN) was added to a 100 mL three-necked flask equipped with a reflux condenser, an electric stirrer and a thermometer. 20 mL of DMF solvent was added, and the mixture was reacted at 20 °C for 4 hours. The mixture was then cooled to room temperature to obtain the prepolymer.
[0046] Step 3:
[0047] The obtained prepolymer was transferred into a polytetrafluoroethylene mold and placed in an oven at 80°C for 24 hours to remove DMF. It was then cured in an oven at 120°C for 4 hours to obtain a recyclable polymer film containing a dynamic network of vinyl amine ester bonds. To further ensure polymer properties, annealing at 120°C for 6 hours was performed.
[0048] Step 4:
[0049] The obtained membrane was shredded and placed in a three-necked flask. A sufficient amount of tetrahydrofuran solution containing 0.1 mol / L hydrochloric acid was added, and the mixture was allowed to stand or be stirred at room temperature for 6 hours. At this time, TREN will react with hydrochloric acid to form an insoluble salt (such as...). Figure 2 As shown in the image, a white precipitate appears. The solution containing acetoacetate and the amine salt (such as...) can be separated by simple filtration or centrifugation. Figure 2 (Middle III, VI).
[0050] The obtained solutions containing acetoacetate monomers or acetoacetate polymers can be neutralized with a 0.1 mol / L NaHCO3 / NaCl solution (1:1 molar ratio), followed by purification by distillation to recover the acetoacetate monomers or polymers. The obtained TREN·HCl insoluble salt can be reduced to TREN by adding a 0.1 mol / L KOH methanol solution, and then purified TREN can be obtained by distillation. The recovered monomers can be directly reacted with acetoacetate polymers to prepare dynamic network polymer materials containing vinylamine ester bonds again.
[0051] like Figure 3 The image shows a comparison of the mechanical properties of the material prepared in the first instance (Original), the material re-prepared after the first recycling (recycle1), and the material re-prepared after the second recycling (recycle2) in this embodiment. Figure 3 It is evident that the vinylamine ester bond-containing dynamic network material (i.e., an environmentally friendly polymer material with a tunable dynamic network) prepared by this invention maintains high mechanical properties while possessing high recycling efficiency.
[0052] Example 2:
[0053] first step:
[0054] In a flask equipped with a magnetic stirrer, ethylene glycol bis(3-mercaptopropionic acid) and allyl acetoacetate were added in a molar ratio of 1:2, followed by 0.5 wt% of the total mass of the two as a photoinitiator, 2-hydroxy-2-methylphenylacetone. The mixture was stirred at room temperature with a wavelength of 365 nm and an intensity of 1200 μW / cm². 2 Irradiation with a UV lamp for 48 hours yielded acetoacetate dimer.
[0055] Step Two:
[0056] A molar ratio of 1:1.2 of acetoacetate dimer and isophorone diamine (IPDA) was added to 20 mL of DMF solution and reacted at 40 °C for 5 hours to obtain the prepolymer.
[0057] Step 3:
[0058] The obtained prepolymer was transferred into a polytetrafluoroethylene mold, baked at 80°C for 24 hours, and then cured at 120°C for 4 hours to obtain a dynamic network polymer film containing vinyl amine ester bonds, and then annealed (at 120°C for 6 hours).
[0059] Step 4:
[0060] The prepared film was shredded and filtered after being added to a 0.1 mol / L tetrahydrofuran hydrochloride solution to obtain a solution containing acetoacetate. After neutralization and purification, the acetoacetate monomer (acetoacetate dimer) was recovered. The amine salt was reduced with KOH methanol solution to obtain a new amine monomer, thus completing the recovery of the raw material components.
[0061] Example 3:
[0062] first step:
[0063] In a flask, trimethylolpropane tris(3-mercaptopropionate) and ethylene glycol acetoacetate methacrylate were added at a molar ratio of 1:3, followed by 0.6 wt% of the total mass of the two as a photoinitiator, phenyldibenzothiophene. The mixture was stirred at 30°C and tested with a wavelength of 365 nm and an intensity of 1000 μW / cm. 2 Irradiation with a UV lamp for 72 hours yielded acetoacetate trimer.
[0064] Step Two:
[0065] Acetylacetate trimer was reacted with hexamethylenediamine (molar ratio 1:1.5), and 20 mL of N,N-dimethylacetamide (DMA) solution was added. The reaction was carried out at 50 °C for 5 hours to obtain the prepolymer.
[0066] Step 3:
[0067] The prepolymer was transferred into a polytetrafluoroethylene mold, baked at 80°C for 24 hours, and then cured at 120°C for 4 hours to obtain a dynamic network polymer film containing vinyl amine ester bonds, which was then annealed (at 120°C for 6 hours).
[0068] Step 4:
[0069] The cured polymer is chopped and filtered in tetrahydrofuran hydrochloride solution to obtain a solution containing acetoacetate. After neutralization and purification of the solution, acetoacetate monomers and acetoacetate polymers can be recovered, and the amine salt can be reduced to amine monomers for recycling.
[0070] Example 4:
[0071] first step:
[0072] In a flask, pentaerythritol tetrakis(3-mercaptopropionic acid) and allyl acetoacetate were added in a molar ratio of 1:4, followed by 0.4 wt% of the total mass of the two as a photoinitiator, phenyldibenzothiophene. The mixture was stirred at 25°C and tested with a wavelength of 365 nm and an intensity of 1500 μW / cm. 2 Irradiation with a UV lamp for 36 hours yielded acetoacetate tetramer.
[0073] Step Two:
[0074] A 1:1.3 molar ratio of acetoacetate tetramer was reacted with tris(2-aminoethyl)amine, and 20 mL of DMF solution was added. The reaction was carried out at 60 °C for 4 hours to obtain the prepolymer.
[0075] Step 3:
[0076] The prepolymer was transferred into a polytetrafluoroethylene mold, baked at 80°C for 24 hours, and then cured at 120°C for 4 hours to obtain a dynamic network polymer film containing vinyl amine ester bonds, and then annealed (at 120°C for 6 hours).
[0077] Step 4:
[0078] After the membrane was shredded, it was filtered with tetrahydrofuran hydrochloride solution to obtain a solution containing acetoacetate; then, the amine salt was reduced with KOH methanol solution to recover the amine monomer.
[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing an environmentally friendly polymer material for a controllable dynamic network, characterized in that, The application relates to a method for preparing an environmentally-friendly polymer material with a controllable dynamic network. The acetoacetic acid alkene is subjected to a photo-polymerization reaction with a mercaptan in a solvent to obtain a multifunctional acetoacetic acid ester polymer; The acetoacetic acid ester polymer is subjected to a cross-linking reaction with a polyamine monomer in a solvent to obtain a prepolymer; the prepolymer is solidified to obtain the environmentally-friendly polymer material with the controllable dynamic network, and annealing treatment is performed, so that the environmentally-friendly polymer material with the controllable dynamic network is obtained. The mercaptan is trimethylolpropane tris(3-mercaptopropionate); the polyamine monomer is tris(2-aminoethyl)amine; the molar ratio of the acetoacetic acid ester polymer and the amine group is 1:1-1.
5. The annealing temperature is 120 DEG C, and the annealing time is 6-8 hours.
2. The method for preparing the environmentally friendly polymer material with adjustable dynamic network as described in claim 1, characterized in that, The acetoacetic acid alkene is acetoacetic acid ethylene glycol methacrylate or acetoacetic acid allyl ester.
3. The method for preparing the environmentally friendly polymer material with adjustable dynamic network as described in claim 1, characterized in that, The molar ratio of the acetoacetic acid alkene and the mercaptan is 1:1-4.
4. The method for preparing the environmentally friendly polymer material with adjustable dynamic network as described in claim 1, characterized in that, The initiator of the photo-polymerization reaction is 2-hydroxy-2-methylpropiophenone or phenyl dibenzothiophene, and the addition amount is 0.4%-0.6% of the total mass of the monomers.
5. A closed-loop recycling method of the environmentally friendly polymer material of the controllable dynamic network prepared by the method of claim 1, characterized in that, The application also relates to a method for recycling the environmentally-friendly polymer material with the controllable dynamic network. The acetoacetic acid ester-containing solution is subjected to neutralization and purification to obtain an acetoacetic acid ester polymer; The amine salt is reduced into an amine by using a methanol solution of KOH.
6. The application of the environmentally-friendly polymer material with the controllable dynamic network prepared by the method in claim 1 in the fields of building industry, transportation packaging, optics or aerospace.