Fully recyclable double dynamic bond-based high-strength epoxy polymer and method for preparing same

Abstract

The present invention relates to a fully recyclable double dynamic bond-based high-strength epoxy polymer and a method for preparing same. The double dynamic bond-based high-strength epoxy polymer according to the present invention is a material that can replace conventional epoxy materials that, due to their characteristics, are difficult to recycle because they cannot be reprocessed once cross-linked. The double dynamic bond-based high-strength epoxy polymer exhibits excellent properties of high strength, reprocessability, and high heat resistance, demonstrates performance sufficient to replace conventional epoxy materials, and is capable of being recycled multiple times, thereby minimizing environmental pollution.

Description

Fully recyclable double dynamic bond-based high-strength epoxy polymer and method for manufacturing the same

[0001] The present invention relates to a fully recyclable double dynamic bond-based high-strength epoxy polymer and a method for manufacturing the same. Specifically, the invention relates to a fully recyclable double dynamic bond-based high-strength epoxy polymer and a method for manufacturing the same, characterized by exhibiting performance sufficient to replace existing epoxy materials while minimizing environmental pollution damage by providing multiple recyclability, and possessing high strength, reprocessability, and high heat resistance.

[0002]

[0003] Epoxy materials are thermosetting polymers with cross-linking between molecular chains, possessing high mechanical strength, chemical resistance, excellent thermal stability, and high specific strength. As such, they are indispensable materials used in the electrical and electronics, automotive, shipbuilding, and aerospace industries, offering limitless applications; however, a problem exists in that once cross-linked, thermosetting epoxy materials can no longer be processed, making recycling difficult and necessitating disposal.

[0004] Epoxy materials are composite resins that are processed into a liquid state by mixing epoxy resin and a curing agent, and are highly versatile as they are produced through processes such as impregnating and mixing fillers such as carbon fiber. They also have low energy consumption for mixing fillers due to the low viscosity of the monomer before curing, and exhibit high mechanical strength, chemical resistance, and thermal stability because they form a cross-linked structure after curing.

[0005] In addition, among the various types of commercial epoxy and curing agents for application under various conditions, carbon fiber reinforced plastic (CFRP) used as a composite material most commonly utilizes bisphenol A-based epoxy resins containing aromatic rings capable of exhibiting high mechanical strength and Jeffamine. However, since epoxy is difficult to recycle because it cannot be processed further once cross-linked, there is a growing need for the development of materials that can be recycled while possessing good physical properties due to recent environmental issues regarding waste polymers.

[0006] Meanwhile, in order to solve the aforementioned problems, research related to Covalent Adaptable Networks (CAN), which are polymers crosslinked by dynamic bonding, is actively being conducted. CAN is a polymer in which the crosslinking between polymer chains is performed by dynamic bonding rather than the permanent covalent bonding of conventional thermosetting resins. The exchange reaction of dynamic bonding is promoted by external stimuli such as heat and light, and since the exchange reaction does not occur before the external stimuli are applied, the overall topology is fixed as if in a frozen state; therefore, the exchange reaction of dynamic bonding in most CANs is promoted by heat.

[0007] For example, the topology freezing transition temperature (T), which is the temperature at which exchange reactions begin to be actively promoted. v Above ) dynamic exchange reactions are actively initiated, molecular topology can be rearranged, and reprocessing is possible. On the other hand, T v At temperatures below this level, it behaves like a typical thermosetting polymer.

[0008] When CAN is introduced, it can be used as an excellent material based on high mechanical strength, chemical resistance, and heat resistance, as a cross-linked polymer with a frozen topology at actual operating temperatures, and when reprocessing / recycling is required, the topology can be rearranged and recycled by applying heat, thereby possessing the advantages of both thermoplastic and thermosetting polymers.

[0009] However, in the case of CAN materials that possess high physical properties based on polymer structures such as high crosslinking density and aromatic rings, the chain mobility is low, requiring harsh reprocessing conditions such as high temperature, high pressure, and long duration. Reprocessing at high temperatures for long periods causes thermal decomposition and oxidation of polymer chains, which significantly reduces performance such as mechanical strength degradation, discoloration, and weather resistance, thereby diminishing the significance of reprocessing.

[0010] As such, even when CAN is recycled multiple times, harsh conditions inevitably reduce the number of recycling cycles, resulting in only one or two cycles, which can diminish the significance of the thermosetting properties that provide recyclability. Additionally, if the introduced reactive dynamic bond is vulnerable to high temperatures, acids, moisture, UV, etc., there is a concern that long-term usability may be significantly reduced due to the breakdown of the functional group and a decrease in the structural stability of the sample.

[0011] Accordingly, the inventors have completed the present invention by developing a high-strength epoxy polymer that possesses high strength, reprocessability, and high heat resistance characteristics, and simultaneously provides multiple recyclability to overcome the aforementioned problems and minimize environmental pollution damage.

[0012]

[0013] The present invention was devised to solve the problems described above, and aims to provide a fully recyclable high-strength epoxy polymer based on dual dynamic bonding and a method for manufacturing the same, characterized by exhibiting performance sufficient to replace existing epoxy materials, minimizing environmental pollution damage by providing multiple recyclability, and possessing high strength, reprocessability, and high heat resistance.

[0014]

[0015] A preferred embodiment of the present invention for achieving the above objective comprises a first monomer containing two or more epoxy groups; a second monomer of an aliphatic carboxylic acid containing sulfur; and a third monomer acting as a catalyst; wherein the third monomer facilitates dual dynamic reactions between the epoxy ring of the first monomer and the two ends of the aliphatic carboxylic acid of the second monomer, thereby providing a fully recyclable high-strength epoxy polymer as a means of solving the problem.

[0016]

[0017] The above dual dynamic reactions may include transesterification and disulfide metathesis reactions.

[0018] The first monomer above may include one or more of the group consisting of bisphenol-based, aminophenol-based, siloxane-based, and alicyclic epoxy resins.

[0019] The second monomer above may be selected from any one of 2,2'-dithiodibenzoic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid, 5,5'-dithiobis(2-nitrobenzoic acid), 6,6'-dithiodinicotinic acid, DL-homocysteine, penicillamine disulfide, and L-glutathione oxidized.

[0020] The above third monomer is preferably 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0021] It is preferable that the above epoxy polymer contains the first monomer (DGEBA) and the third monomer (TBD) in a molar ratio of 1 to 2.5 : 0.02 to 0.04, respectively, for every 1 mole of the second monomer (DTDA).

[0022] The above epoxy polymer is characterized by being reusable after being decomposed when heated by being immersed in an aqueous solution of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0023] The above epoxy polymer is characterized by having shape memory properties that return to its original shape at a temperature above its glass transition temperature (Tg).

[0024]

[0025] Another preferred embodiment of the present invention for achieving the above objective is a method for manufacturing a fully recyclable high-strength epoxy polymer, characterized by comprising the steps of: mixing and heating a first monomer and a second monomer to produce a transparent solution; mixing a third monomer into the transparent solution and stirring to produce a mixture; pouring the mixture into a mold and heating to pre-cure it; and heating the pre-cured mixture under vacuum to main-cure it; as another means of solving the problem.

[0026] The first monomer above may include one or more of the group consisting of bisphenol-based, aminophenol-based, siloxane-based, and alicyclic epoxy resins.

[0027] The second monomer above may be selected from any one of 2,2'-dithiodibenzoic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid, 5,5'-dithiobis(2-nitrobenzoic acid), 6,6'-dithiodinicotinic acid, DL-homocysteine, penicillamine disulfide, and L-glutathione oxidized.

[0028] The above third monomer is preferably 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0029] In the step of preparing the transparent solution above, it is preferable to mix the first monomer (DGEBA) in a ratio of 1 to 2.5 moles to 1 mole of the second monomer (DTDA), and in the step of preparing the mixture above, to mix the third monomer (TBD) in a ratio of 0.02 to 0.04 moles.

[0030] In the above transparent solution preparation step, it is preferable to heat to 170 to 190°C, in the above pre-curing step, heat-cure at a temperature of 170 to 190°C for 45 to 75 minutes, and in the above main curing step, heat-cure at a temperature of 170 to 190°C for 3 to 10 hours at a vacuum pump pressure of 0 to 0.1 MPa.

[0031]

[0032] The dual dynamic bond-based high-strength epoxy polymer according to the present invention is a material capable of replacing conventional epoxy materials, which have the disadvantage of being difficult to recycle because they cannot be reprocessed once crosslinked. It exhibits excellent characteristics of high strength, reprocessability, and high heat resistance, demonstrating performance sufficient to replace existing epoxy materials, while simultaneously enabling multiple recyclability, thereby having the effect of minimizing environmental pollution damage.

[0033] Accordingly, the inventors have completed the present invention by developing a high-strength epoxy polymer that possesses high strength, reprocessability, and high heat resistance characteristics, and simultaneously provides multiple recyclability to overcome the aforementioned problems and minimize environmental pollution damage.

[0034]

[0035] FIG. 1 is a figure showing the ATR-FTIR measurement results according to the DGEBA content of E-CAN (Epoxy-Covalent Adaptable Networks, E-CAN) according to a preferred embodiment of the present invention.

[0036] Figure 2 is a diagram showing the results of measuring the gel content of E-CAN according to curing time (2-hour intervals).

[0037] Figure 3 is a diagram showing the results of measuring the curing temperature range in the first heating cycle of the E-CAN after 4 hours of curing.

[0038] Figure 4 shows the glass transition temperature (T) in the second heating cycle of the E-CAN after 4 hours of curing. g This is a drawing showing the measurement results.

[0039] Figure 5 is a diagram showing the tensile strength of E-CAN for CFRP and the results of measuring the strength of conventional epoxy.

[0040] Figure 6 is a diagram showing the results of measuring the tensile strength and conventional epoxy strength of an E-CAN for CFRP after three cycles of recycling.

[0041] Figure 7 is a photograph showing the state of the E-CAN after reprocessing under constant temperature / pressure conditions.

[0042] Figure 8 shows E-CAN (R1, R1.5, R2, R2.3, R2.5) and T according to the concentration of DGEBA. d5% This is a diagram showing the TGA measurement results.

[0043] Figure 9 is a diagram showing the measurement results of the storage modulus through the temperature sweep of the E-CAN.

[0044] Figure 10 is a diagram showing the loss factor obtained through the temperature sweep of the E-CAN.

[0045] Figure 11 is a diagram showing the results of E-CAN fitting through the WLF equation and the Arrhenius equation using the relaxation time of stress relaxation measured by temperature.

[0046] Figure 12 is a photograph showing the condition of the original E-CAN-R2.3 and various solvents after 24 hours on a hot plate at 160°C.

[0047] Figure 13 is a diagram showing the FT-IR peak measurement results of the original E-CAN-R2.3 and the decomposed E-CAN-R2.3.

[0048] Figure 14 is a figure showing the results of measuring the weight percentage of chemical decomposition at H2O / TBD 160℃ / 12 hours.

[0049] Figure 15 is a photograph showing the process of recycling E-CAN-R2.3 without an additional purification process.

[0050] Figure 16 shows the FT-IR peak measurement results according to the weight fraction of recycled E-CAN-R2.3 after chemical decomposition in H2O / TBD at 160℃ / 12 hours without additional purification process.

[0051] Fig. 17 shows the glass transition temperature (T) of the E-CAN g This is a photograph showing the shape memory process at a temperature higher than ).

[0052] Fig. 18 shows the topological freezing transition temperature (T v The above is a photograph showing the process of the E-CAN returning to its windmill shape after stress relaxation occurs and the shape is fixed in the windmill shape.

[0053]

[0054] The present invention will be described in detail below according to preferred embodiments with reference to the attached drawings, but specific descriptions of configurations and operations that are readily known to those skilled in the art will be omitted. Furthermore, it should be noted that the present invention is not necessarily limited by the following embodiments and that various modifications can be made to the invention within the scope of the technical concept of the invention.

[0055] The terms used in this specification have been selected to be as widely used as possible, taking into account their functions in the present invention; however, in specific cases, terms have been arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the description of the invention. Accordingly, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall content of the invention.

[0056]

[0057] Hereinafter, a preferred embodiment according to the present invention will be described in detail regarding a fully recyclable double dynamic bond-based high-strength epoxy polymer.

[0058] The dual dynamic bond-based high-strength epoxy polymer according to the present invention comprises a first monomer containing two or more epoxy groups; a second monomer of an aliphatic carboxylic acid containing sulfur; and a third monomer acting as a catalyst, and is simply synthesized by a dual dynamic reaction (DDR) by the third monomer, which assists the reaction between the epoxy ring of the first monomer and the two ends of the aliphatic carboxylic acid of the second monomer.

[0059]

[0060] High-strength epoxy polymers based on dual dynamic bonding are synthesized by a dynamic bonding network (Covalent Adaptable Networks, CAN) through a dual dynamic reaction (DDR) between the first monomer and the second monomer, namely transesterification and disulfide metathesis reactions, as shown in Reaction Scheme 1 below.

[0061] In the specification of the present invention, the ‘double dynamic bond-based high-strength epoxy polymer’ is synthesized by a dynamic bond network (CAN) as described above, so it is named ‘epoxy CAN’ or ‘E-CAN’.

[0062] The first monomer above may include one or more of the group consisting of bisphenol-based, aminophenol-based, siloxane-based, and alicyclic epoxy resins.

[0063] Specifically, it is preferable that it be bisphenol A diglycidyl ether (DGEBA).

[0064] The second monomer above may be selected from any one of 2,2'-dithiodibenzoic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid, 5,5'-dithiobis(2-nitrobenzoic acid), 6,6'-dithiodinicotinic acid, DL-homocysteine, penicillamine disulfide, and L-glutathione oxidized.

[0065] Specifically, it is preferable that it be 4,4'-dithiodibutyric acid (DTDA).

[0066] In the present invention, only the two ends of dithiodibutyric acid (DTDA) can form ester-hydroxy groups that enable transesterification, and also have disulfid bonds, so the ratio of the exchange reaction group can be controlled only by the equivalent ratio of DTDA. By utilizing this, dynamic crosslinking and permanent crosslinking densities can be controlled by adjusting the ratio of bisphenol A-based epoxy resin while fixing the equivalent ratio of DTDA.

[0067] In addition, the crosslinking density can also be controlled through homopolymerization via hydroxyl groups, etherification, and ring opening of the epoxy itself, so the properties of the material, such as mechanical strength, heat resistance, and recyclability, can be controlled as desired.

[0068] The above third monomer is preferably 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0069]

[0070] In addition, it is preferable that the epoxy CAN contains the first monomer (DGEBA) and the third monomer (TBD) in a molar ratio of 1 to 2.5 : 0.02 to 0.04, respectively, for every 1 mole of the second monomer (DTDA).

[0071] The above epoxy can is completely decomposed by immersing 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) in a mixed solution of water and TBD, and then reacting it at 140 to 180°C for 12 to 24 hours, and the water in the decomposed epoxy can is evaporated so that it can be reused as a raw material.

[0072] In the above, for the mixed solution of water and TBD, it is preferable to use an aqueous solution in which 0.69 to 1.39 g of TBD is dissolved in 10 ml of water.

[0073] In the present invention, the mixing ratio of the first monomer, the second monomer, and the third monomer is preferably within the range specified above, and if it deviates from the range specified above, there is a risk that inefficient synthesis will be performed due to residual unreacted material.

[0074] In addition, the epoxy CAN may have shape memory properties that return to its original shape at a temperature above the glass transition temperature (Tg).

[0075] The epoxy CAN according to the present invention preferably has a molecular weight (Mc) between crosslinks of 2,000 to 25,000.

[0076]

[0077] The epoxy CAN synthesis reaction according to the present invention specifically involves dual dynamic reactions as shown in Reaction Scheme 1 below, and the reaction may include transesterification and disulfide metathesis reactions.

[0078] Accordingly, the present invention synthesizes an epoxy CAN having two dynamic bonds of ester exchange and disulfide metathesis simultaneously, thereby including a plurality of exchange reactors within the molecular space, and a topological freezing temperature (T v Compared to when it is a single-type dynamic bond, it is reduced, and accordingly, reprocessing is possible under relaxed conditions.

[0079] In addition, the present invention enables relatively simple synthesis and promotion of exchange reactions by using only one type of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) catalyst that acts effectively in both exchange reactions, making it suitable for high-strength epoxy materials that inevitably have harsh reprocessing conditions, which can induce the possibility of multiple reprocessing of epoxy materials with high mechanical strength, in addition to a high recovery rate of reprocessing properties.

[0080] [Reaction Equation 1]

[0081] [Correction pursuant to Rule 91 02.12.2025]

[0082]

[0083] The above epoxy CAN synthesis reaction is a dual dynamic reaction, and the reactions of Reaction Schemes 2.1 to 2.4 below take place.

[0084] In reaction scheme 2.1 below, the epoxy ring of DGEBA reacts with the carboxylic acid of DTDA to produce ester groups and hydroxyl groups, thereby forming a molecular structure capable of transesterification.

[0085] [Reaction Equation 2.1]

[0086]

[0087]

[0088] In addition, due to the disulfide bonds within DTDA, dual dynamic networks with two exchange reaction networks are formed. As shown in Reaction Scheme 2.2 below, an excess epoxy ring at the epoxy terminal is attached to the remaining hydroxyl group, causing etherification, and a permanent cross-linked structure is formed that does not undergo exchange reactions without dynamic bonding.

[0089] [Reaction Equation 2.2]

[0090]

[0091]

[0092] Reaction schemes 2.3 and 2.4 below represent additional reactions that may occur. As shown in reaction scheme 2.3, condensation esterification takes place, and as shown in reaction scheme 2.4, ether bonds can be formed through homopolymerization of the epoxy itself, thereby forming a permanent crosslinked structure. In other words, as the content of DGEBA increases, not only does the density of crosslinking increase, but the ratio of permanent crosslinking to dynamic crosslinking can also be predicted to increase.

[0093] TBD acts as a catalyst to facilitate the reaction between the epoxy ring and the carboxylic acid ends. Additionally, TBD acts as a catalyst for two exchange reactions within the generated epoxy CAN: ester exchange and sulfide metalysis.

[0094] [Reaction Equation 2.3]

[0095]

[0096]

[0097] [Reaction Equation 2.4]

[0098]

[0099]

[0100] Meanwhile, another preferred embodiment according to the present invention provides a method for manufacturing a fully recyclable double dynamic bond-based high-strength epoxy polymer (epoxy CAN).

[0101] The method for manufacturing the above epoxy CAN may include the step of preparing a transparent solution by mixing and heating a first monomer and a second monomer; the step of preparing a mixture by mixing a third monomer into the transparent solution and stirring; the step of pre-curing the mixture by pouring it into a mold and heating it; and the step of main-curing the pre-cured mixture by heating it under vacuum.

[0102] As the first monomer, second monomer, and third monomer mentioned above have been explained in detail above, their explanation will be omitted here.

[0103] In the step of preparing the transparent solution above, it is preferable to mix the first monomer (DGEBA) in a ratio of 1 to 2.5 moles for every 1 mole of the second monomer (DTDA), and in the step of preparing the mixture above, to mix the third monomer (TBD) in a ratio of 0.02 to 0.04 moles.

[0104] In addition, it is preferable to heat to 170 to 190°C in the transparent solution preparation step, heat cure at a temperature of 170 to 190°C for 45 to 75 minutes in the pre-curing step, and heat cure at a temperature of 170 to 190°C for 3 to 10 hours at a vacuum pump pressure of 0 to 0.1 MPa in the main curing step.

[0105]

[0106] For reference, when describing the method for manufacturing a high-strength epoxy polymer according to the present invention, the mixing ratio of the compounds and process conditions specified above may produce an epoxy polymer with optimal physical properties when within the range specified above, but are not necessarily limited to the process conditions above and can be appropriately adjusted.

[0107]

[0108] Hereinafter, the present invention will be described in detail with reference to examples to aid in understanding. However, the following examples are merely illustrative of the content of the present invention and the scope of the present invention is not limited to the following examples. The examples of the present invention are provided to more completely explain the present invention to those with average knowledge in the art.

[0109]

[0110] 1. Synthesis of E-CAN (Epoxy-Covalent Adaptable Network)

[0111] With the ratio of 4,4'-dithiodibutyric acid (DTDA) fixed at 1 molar, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was used at 0.03 molar, and bisphenol A diglycidyl ether (DGEBA) was used at ratios of 1, 1.5, 2, 2.3, and 2.5 molar, respectively, to synthesize a double dynamic bond-based high-strength epoxy polymer (E-CAN) as shown below.

[0112] First, DGEBA was stirred at 200 rpm on a hot plate at 180°C, then DTDA was added and stirring continued until it became a transparent liquid. After it became a transparent liquid, TBD was added and the mixture was stirred for 5 minutes. The resulting solution was then poured onto a Teflon sheet and pre-cured in a hot press at 180°C for 1 hour. Then, the pre-cured sample was placed in a vacuum oven with a vacuum pump pressure of 0 to 0.1 MPa and cured for 3 hours to produce an E-CAN sample.

[0113] As described above, the E-CAN synthesized by proceeding with the synthesis of DGEBA at molar ratios of 1, 1.5, 2, 2.3, and 2.5, respectively, was named 'E-CAN-R#' according to the ratio (#) of DGEBA to DTDA, and specifically denoted as E-CAN-R1, E-CAN-R1.5, E-CAN-R2, E-CAN-R2.3, and E-CAN-R2.5, respectively.

[0114]

[0115] 2. E-CAN Characterization Analysis

[0116] <Experimental Example 1> Confirmation of E-CAN Synthesis

[0117] Since there were no issues with the monomer ratios used in the above synthesis, attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) analysis was performed at an 8cm height to identify residual monomers and to verify whether the desired chemical structure had been formed. -1 32 scans at the resolution of 4000~650cm -1 , 1720cm -1 The results of ATR-FTIR measurements under COOR conditions are shown in Figure 1.

[0118] For reference, Fig. 1a is the total FT-IR of E-CAN-R# according to the DGEBA ratio and DGEBA monomer, and f. 1b is the epoxy peak (910 cm⁻¹) before and after synthesis. -1 ) change, where c is the increase in aromatic C=C bond peaks according to the DGEBA content of E-CAN-R#, and d is the increase in aromatic ether bond peaks according to the DGEBA content of E-CAN-R#.

[0119] When comparing the pre- and post-curing states, the disappearance of the epoxy peak in the ATR-FTIR spectrum was confirmed as shown in Fig. 1(b), which confirms that complete curing was achieved without any residual monomer.

[0120] In addition, as shown in Fig. 1(c), it was observed that as the content of the benzene ring in the 1580 cm⁻¹ wavelength range gradually increased, it was correctly normalized, and at the same time, a stiffer material was formed.

[0121] Subsequently, as shown in Fig. 1(d), through the increase in the ester peak in the 1230 cm⁻¹ wavelength range, it was predicted that the etherification of the hydroxyl group and the epoxy ring and the homopolymerization of the epoxy itself would occur, leading to a higher crosslinking density and an increase in the proportion of permanent crosslinks.

[0122]

[0123] <Experimental Example 2> Confirmation of Optimal Curing Conditions

[0124] To verify whether crosslinking between polymer chains was properly performed, a gel content measurement experiment was conducted. To determine the mass change of samples cured at 160°C at different times, the gel content was determined by swelling in tetrahydrofuran for 24 hours followed by drying in a vacuum oven for 24 hours. The solvent dissolves DGEBA and DTDA but does not dissolve E-CAN.

[0125] Referring to Figure 2, 4 hours was selected as the optimal curing condition because the gel content flattened out at over 90% even when measured in 2-hour intervals starting from 4 hours. Subsequently, the curing condition for all specimens was standardized to 4 hours.

[0126]

[0127] <Experimental Example 3> Glass transition temperature (T g Confirmation of )

[0128] In differential scanning calorimetry (DSC) analysis, samples that have not fully undergone curing develop an exothermic peak because a cross-linked structure is formed near the curing temperature and regularity increases. As a result of verifying the first heating cycle near the curing temperature by heating E-CAN-R# samples from 25°C to 200°C in a nitrogen atmosphere, cooling to -80°C, and heating again to 200°C using DSC, it was confirmed once again that the samples were fully cured because no peak occurred near the curing temperature of 180°C, as shown in Figure 3.

[0129] In addition, the glass transition temperature (T) of the polymer through DSC analysis of E-CAN-R# g Verification of ) was carried out, and in order to eliminate the effect of cold crystallization, T in the second heating cycle g confirmed.

[0130] T g By definition, it is the temperature at which segmental motion of a polymer begins, and T g From temperatures above this level, the free volume increases, and the molecular motion of the polymer chains becomes significantly more active, so the thermal capacity increases.

[0131] Therefore, through the fact that an inflection point occurs in the end-up direction of the line in the DSC graph, T g I was able to confirm T g It was defined based on the exact center of the inflection point.

[0132] As the DGEBA content increases, the benzene ring and crosslinking density gradually increase. Since high crosslinking density and benzene rings hinder the segmental motion of the polymer chain, chain mobility decreases as the DGEBA content increases, as shown in Fig. 4, T g You can confirm that it is increasing.

[0133]

[0134] <Experimental Example 4> Confirmation of Mechanical Properties

[0135] To verify the mechanical properties of E-CAN, a 15 × 7 × 2 mm rectangular sample was tensile-stretched at a speed of 12.7 mm / min using a universal testing machine (UTM) to measure the elastic modulus and ultimate tensile strength (UTS) of the sample.

[0136] Tensile strength was measured using a UTM to compare mechanical strength with existing epoxy materials for CFRP, and E-CAN-R1.5 to E-CAN-R2.5 were installed on extensometers to accurately measure strain. E-CAN-R1 was not installed because it bends when an extensometer is mounted.

[0137] Cross-linked polymers exhibit higher mechanical strength compared to thermoplastic polymers because primary intermolecular bonding forces are formed. Additionally, aromatic rings make the polymer stiffer. The elastic modulus was measured using a slope between 0.05% and 0.25% strain, which falls within the elastic deformation range of high-stiffness materials. UTS was defined as the stress value at which the E-CAN fractures.

[0138] As shown in Figure 5, it was confirmed that the elastic modulus and UTS gradually improved as the DGEBA content increased, leading to an increase in the benzene ring and crosslinking density. The rapid increase in strength starting from R2 is predicted to be due to a rapid increase in crosslinking density caused by etherification. The elastic modulus of existing epoxy materials for composites was 2–6 GPa, and the UTS was 20–100 MPa, as indicated in Figure 5. By controlling the content of the DGEBA monomer, it was confirmed that the materials from E-CAN-R2 to E-CAN-R2.5 had a synthesis ratio of E-CAN similar to the physical strength of existing epoxy materials for composites. Table 1 below shows the average values ​​of the elastic modulus and UTS from three tensile strength tests of E-CAN.

[0139]

[0140] CategoryE-CAN-R1E-CAN-R1.5E-CAN-R2E-CAN-R2.3E-CAN-R2.5Avg. Elastic modulus (GPa)0.823.424.174.575.16Avg. UTS(MPa)3.7116.737.245.652.3

[0141]

[0142] <Experimental Example 5> Confirmation of Recyclability of E-CAN-R#

[0143] To verify the thermal recyclability and property recovery rate of E-CAN, tensile strength was measured using a Universal Testing Machine (UTM) at a speed of 12.7 mm / min for rectangular samples of 15 × 7 × 2 mm following three grinding cycles and subsequent reprocessing. The grinding was performed using a freezer mill to produce very fine particles.

[0144] E-CAN-R1 and E-CAN-R1.5 were reprocessed via hot pressing under conditions of 130°C and 20 MPa for 3 hours, while E-CAN-R2 and E-CAN-R2.3 were reprocessed via hot pressing under conditions of 160°C and 20 MPa for 3 hours. As shown in Figure 6, the samples reprocessed three times exhibited an elastic modulus and UTS of 80% compared to the original values. Table 2 below shows the average values ​​of elastic modulus and UTS measured three times in the tensile strength test for the E-CAN recycled three times. A significant advantage is the ability to recycle three times in addition to mechanical strength similar to that of existing epoxy materials. The high property recovery rate observed even after multiple reprocessing is thought to be due to the introduction of two exchange reactions, which resulted in relatively relaxed reprocessing conditions. Furthermore, the high thermal stability resulting from a stable structure due to aromatic rings and high crosslinking density is also considered a reason for the high property recovery rate observed during multiple recycling cycles. As shown in Figure 7, the E-CAN-R2.5 sample had a high proportion of permanent crosslinks and a low chain mobility due to the increase in benzene ring and crosslink density, so it was partially reprocessed at temperature conditions of 160°C, 180°C, and 200°C, but complete reprocessing was not possible.

[0145]

[0146] Classification E-CAN-R1 E-CAN-R1.5 E-CAN-R2 E-CAN-R2.3 E-CAN-R2.5 Avg. Elastic Modulus (GPa) 0.79 2.75 3.22 3.66 × Avg. UTS (MPa) 3.71 6.89 2.5.43 5.2 ×

[0147]

[0148] <Experimental Example 6> Confirmation of Thermal Stability of E-CAN-R#

[0149] The thermal stability of E-CAN-R# was verified through thermogravimetric analysis (TGA) at temperatures ranging from 30°C to 800°C with a heating rate of 5°C / min. As a result, as shown in Fig. 8, all samples T d5% (The temperature at which mass loss reaches 5% in TGA) appeared and thermal decomposition began.

[0150] The aromatic ring of DGEBA is thermally stable due to the structural rigidity of the molecule resulting from resonance structures. Furthermore, thermosetting polymers possess higher thermal stability compared to thermoplastic polymers; they are more stable against thermal decomposition due to the structural stability provided by cross-linking and intermolecular bonding.

[0151] Similarly, it was confirmed that heat resistance gradually increased as the content of DGEBA, a polymer with high crosslinking density, increased. It is judged that this results in superior heat resistance because increasing the DGEBA content increases the proportion of permanent crosslinking compared to dynamic crosslinking, which is prone to thermal degradation. Subsequently, all experiments were conducted in which the samples did not decompose T d5% It was conducted at the following temperatures.

[0152]

[0153] <Experimental Example 7> Confirmation of Stress Relaxation Characteristics of E-CAN-R#

[0154] DMA-amplitude sweep

[0155] To verify the stress relaxation characteristics of E-CAN-R#, a rectangular sample of 5 mm × 1 mm × 18 mm was measured using a dynamic mechanical analyzer (MCR 702e) at a strain of 0.1% and 1 Hz, while increasing the temperature from 0℃ to 200℃ at a rate of 3℃ / min.

[0156] For stress relaxation, the results of stress relaxation were measured over 1000 s while applying a constant deformation of 0.1% to a single sample at a temperature lowered by 10℃ from a high temperature.

[0157] When a deformation is applied to a polymer sample, there is a deformation range in which the sample can return to its original state upon removal due to entanglement to some extent. If a deformation greater than this is applied, the molecular bonds break, and the sample cannot return to its original state. If a force at the level of molecular bond breakdown is repeatedly applied, fatigue accumulates, causing deformation of the sample and rendering the data unreliable. To prevent this problem, a DMA-amplitude sweep was performed to measure the Linear Viscoelastic Region (LVR), which is the range in which the sample can elastically return to its original state.

[0158] Measurements were taken at 1 Hz, increasing the logarithmic scale from 0.01% to 20%. The range before the point where E' and E'' begin to decrease, after an equilibrium region appears during measurement, is defined as LVR. The measurement results confirmed that all samples formed an LVR within 0.1% under 30°C conditions in the DMA. Subsequent experiments were conducted under a strain of 0.1%.

[0159]

[0160] DMA-Temperature sweep

[0161] T gTo confirm the rubbery plateau characteristics, a rectangular sample of 5 mm × 1 mm × 18 mm was measured using a dynamic mechanical analyzer (MCR 702e) at a strain of 0.1% and 1 Hz, while increasing the temperature from 0℃ to 200℃ at a rate of 3℃ / min.

[0162] T g and to verify the height of the rubbery plateau. The glass transition temperature is defined as the temperature at which segmental motion of polymer chains begins. According to this definition, the most correct method is to directly observe the changes in E' and E'' while applying deformation to the polymer sample. g It is a measurement method. The cross-linked polymer is T g Since it does not possess complete flowability even at temperatures above this level, E', which exhibits solid characteristics, is continuously maintained. The height to which this E' is maintained is proportional to the crosslinking density of the polymer. This flat E' is called the rubbery plateau. As shown in Fig. 9, it can be seen that the rubbery plateau gradually rises as the crosslinking density increases with increasing EBA content. g was defined as the peak where the stiff characteristics begin to become rubbery, having the largest value of E'' / E', which is defined as the loss factor. As shown in Fig. 10, as the DGEBA content increases, T g It was confirmed that it gradually increased. A shoulder peak occurs around 60–75°C, which is due to the homopolymerization of DGEBA itself. As the DGEBA content increases, the temperature of the shoulder peak changes according to the T of DGEBA. gIt becomes clear as it approaches 75°C. In addition, as the content of DGEBA increases, the peak of the loss factor decreases, which is predicted to be due to the reduced chain mobility and lower heat dissipation capacity caused by the aromatic ring and high crosslinking density.

[0163] For reference, Fig. 9 shows the storage modulus viewed through the temperature sweep of the E-CAN, measured at a heating rate of 3°C / min from 0°C to 200°C at a frequency of 1 Hz with a strain of 0.1%, and Fig. 10 shows the loss factor viewed from the temperature sweep of the E-CAN, where loss factor = loss modulus / storage modulus. Measured at a heating rate of 3°C / min from 0°C to 200°C at a frequency of 1 Hz with a strain of 0.1%. T g is the center of the loss factor peak.

[0164]

[0165] The addition of an excess amount of DGEBA increases the crosslinking density through etherification. It was confirmed that the crosslinking density clearly increased when compared with the result of E'. To verify whether an actual increase in crosslinking density occurred, the density was measured and the molecular weight of the crosslinked molecular chain, Mc, was determined using the formula below.

[0166] The temperature obtained by substituting into the formula Mc=3ρRT / E is the temperature of the rubbery plateau region (T= T g + 50) Storage modulus E' at that temperature (at T g The value at + 50) was entered and calculated.

[0167] In fact, it can be seen that the crosslinking density increased significantly and had a significant effect on tensile strength, as the molecular weight between molecular chains, Mc, decreased significantly from E-CAN-R2, which is the point where physical properties increase significantly as the DGEBA content increases. Table 3 below shows the molecular weight (Mc) of the molecular crosslinking chains obtained using the formula Mc=3ρRT / E'.

[0168]

[0169] Categoryρ(g / cm3)at 22℃Tg(℃)E'(MPa)Mc(g / mol)E-CAN-R11.25340.4467624924E-CAN-R1.51247700.942121297 9E-CAN-R21.242773.04344073E-CAN-R2.31.238934.073157E-CAN-R2.51.231066.40982054

[0170]

[0171] DMA-Stress Relaxation Verification

[0172] Due to their cross-linked structures, the degree of stress relaxation in thermosetting polymers is very minimal. However, E-CAN-R#, which undergoes disulfide metalysis and ester exchange reactions, can exhibit stress relaxation behavior similar to that of thermoplastic polymers because it possesses flowability. Stress relaxation is a phenomenon in which the stress applied to a polymer decreases over time due to the flow of molecular chains when a constant deformation is applied to the polymer. The time required for the measured stress to become 1 / e of the initial stress after stress relaxation is defined as the relaxation time. In the relatively low-temperature range, the Williams-Landel-Ferry (WLF) equation, which follows segmental motion based on free volume theory, is dominant. In the high-temperature range, chemical reactions—specifically exchange reactions—occur, and this behavior is dominated by the Arrhenius equation. Since both equations contain a relaxation time term dependent on temperature, the relaxation time was calculated by observing the progression of stress relaxation at each temperature. After plotting each temperature and relaxation time on the x- and y-axis, WLF fitting was performed on the relatively low-temperature range and Arrhenius equation fitting on the high-temperature range, based on the region where the trend changes. The reason the polymer behavior follows the Arrhenius equation after a certain temperature is that exchange reactions begin to be predominantly activated. The point where the two equations intersect is the topological freezing transition temperature (T v It was determined that... The temperature condition for the preceding UTM reprocessing was T obtained from rheological properties v It was decided as. T v Since exchange reactions are dominant from the above temperature, T v Reprocessing was possible at temperatures above this level. The reason why reprocessing becomes increasingly difficult due to high benzene ring content and crosslinking density is the topological freezing transition temperature T vThis could be confirmed by the increase. The activation energy was expressed using terms from the Arrhenius equation and represents the slope of the graph. This can be interpreted as the degree to which the relaxation time changes with temperature. Since the relaxation time depends on the exchange reaction, having a high activation energy means that the rate at which the exchange reaction is activated is greater even with slight temperature changes.

[0173] As shown in Fig. 11, as the DGEBA content increases, T v , shows a tendency for activation energy to increase. T v Based on , the WLF equations and the Arrhenius equations are dominant before and after, but they are not 100% completely dominant. v The preceding and subsequent behaviors influence each other, and the ratio of the two behaviors gradually changes with temperature. E-CAN, which has extremely low chain mobility due to high crosslinking density and benzene ring content, shows a high E in the WLF equation a It is interpreted that the activation energy in the region where exchange reactions are dominant increases due to such influence. The difference in activation energy between E-CAN-R1.5 and E-CAN-R2, where the DGEBA content doubles from 1.5 to 2, is very high, which is due to tensile strength and the crosslinking molecular weight M. c It is also a section where a rapid increase occurs. In the case of R2.5, as shown in Fig. 11e, since it largely follows the fitting of WLF rather than the fitting of the Arrhenius equation, it can be interpreted that there is almost no exchange reaction and the reworkability is very low.

[0174] For reference, Figure 11 shows the results of E-CAN fitting using the WLF equation and the Arrhenius equation using the relaxation time of stress relaxation measured by temperature.

[0175] Table 4 below summarizes the overall physical characteristics of the E-CAN measured above.

[0176]

[0177] CategoryE-CAN-R1E-CAN-R1.5E-CAN-R2E-CAN-R2.3E-CAN-R2.5Tg(DSC)4753607075Tg(DMA)34707793106Avg. Elastic modulus (GPa)0.823.424.174.575.16Avg. UTS(MPa)3.7116.737.245.652.3Avg. Elastic modulus (GPa)_Recycled0.792.753.223.66×Avg. UTS(MPa)_Recycled3.716.8925.435.2×T d5% (℃)228278284293310Mc(g / mol)2492412979407331572054Tv(℃)125133150165222Ea(kJ / mol)118120172178198

[0178]

[0179] <Experimental Example 8> Chemical Decomposition and Recycling

[0180] As shown in Fig. 12, chemical decomposition was carried out on E-CAN-R2.3 using various solvents on a hot plate at 160°C for 24 hours. Ester exchange within the E-CAN occurred at high temperatures above 160°C under TBD conditions. Reaction Scheme 3 below represents the decomposition mechanism under high-temperature 1 M H2O / TBD conditions; as the ester groups within the E-CAN and the -OH groups of the low-molecular-weight H2O undergo ester exchange, the molecular chains are gradually cleaved, leading to decomposition. Consequently, the formation of carboxylic acid groups was confirmed via FT-IR, as shown in Fig. 13. The decomposed E-CAN can be reused as a raw material by evaporating the water.

[0181] It is expected that high-temperature H2O easily penetrated into the E-CAN containing a large number of hydrophilic functional groups, such as -OH groups and ester groups. As shown in Fig. 14, it was confirmed that the penetrated TBD and H2O completely decomposed the E-CAN within 12 hours. For reference, Fig. 14 shows the weight percentage of chemical decomposition of H2O / TBD at 160°C / 12 hours.

[0182] [Reaction Equation 3]

[0183]

[0184]

[0185] Conventional CAN materials primarily utilized organic solvents that can be toxic to humans or the environment. However, as shown in Fig. 15, environmentally friendly water was used as the solvent, and the material was decomposed through a simple process by simply adding TBD, which is used as a catalyst for E-CAN, and boiling it. It can be reused as a raw material immediately by simply evaporating the water, without any separate purification or recovery processes. Furthermore, this demonstrates that even E-CAN-R2.5, which is impossible to recycle due to its low reprocessing capacity, can be recycled through chemical decomposition. As shown in Fig. 16, recycling was performed by adding 10 wt%, 20 wt%, and 30 wt% of the decomposed E-CAN to the original E-CAN monomer. Almost identical states and FT-IR peaks were observed. It appears that existing E-CAN-R1 to E-CAN-R2.3 materials will also be able to demonstrate the ability to fully recover their physical properties by returning them to the initial monomer, even if their properties deteriorate due to multiple reprocessing steps.

[0186] For reference, Fig. 15 is a photograph showing the process of recycling E-CAN-R2.3 without an additional purification process, and the recycling process was the same as before, using the same curing conditions of 180°C and 4 hours. Fig. 16 shows the FT-IR peak measurement results according to the weight fraction of recycled E-CAN-R2.3 without an additional purification process after chemical decomposition in H2O / TBD at 160°C / 12 hours.

[0187]

[0188] As confirmed through the above examples, the E-CAN according to the present invention enables ester exchange by forming esters and hydroxyl groups through the reaction of an epoxy ring and a carboxylic acid, and introduces a dual dynamic network that induces a disulfide double decomposition reaction through disulfide bonds within DTDA, thereby obtaining relaxed reprocessing conditions.

[0189] As a result of controlling the ratio of dynamic and permanent crosslinking and the crosslinking density by adjusting the DGEBA content, mechanical strength similar to conventional epoxy strength was exhibited starting from E-CAN-R2, where the ratio and density of permanent crosslinking began to increase rapidly. However, it was confirmed that complete reprocessing was not possible starting from the E-CAN-R2.5 ratio, where chain mobility significantly decreases. The monomer used in conjunction is DTDA, which has a disulfide group and a carboxylic acid terminal.

[0190] Epoxy materials, which possess the advantage of high strength, have low chain mobility, so reprocessing conditions can be eased by introducing two exchange reactions. As the content of DGEBA increased, high benzene ring content and high crosslinking density were induced, gradually improving mechanical properties. At the ratio of E-CAN-R2.3, it was possible to produce E-CAN that has mechanical strength similar to conventional epoxy and a property recovery rate of over 80% even after three reprocessing cycles.

[0191] In the measurement of rheological properties, as the DGEBA content increases, T v It shows that the activation energy gradually increases. This appears to be due to the decrease in chain mobility. The benzene ring and high crosslinking density hinder the exchange reaction of dynamic bonds, making reprocessing difficult. Therefore, UTM measurements could not be performed on E-CAN-R2.5 due to the difficulty of reprocessing.

[0192] It was confirmed that E-CAN, whose physical properties had deteriorated after multiple reprocessing steps, was completely decomposed within 12 hours under high-temperature H2O / TBD conditions. Decomposition occurred through an exchange reaction with the -OH groups of high-temperature water under TBD conditions, which act as a catalyst for the exchange reaction. By mixing a portion of the decomposed E-CAN with the original monomer, it was possible to recycle the sample to obtain one with nearly similar FT-IR peaks.

[0193]

[0194] <Experimental Example 9> Shape Memory and Reconstruction Possibility

[0195] As shown in Table 1 above, E-CAN-R2.3 exhibited a high elastic modulus of 4.57 GPa even at room temperature. Based on this high elastic modulus, T, at which the sample begins to soften g It exhibits high elasticity by maintaining a high modulus of elasticity even at temperatures above. Based on this high mechanical strength, after folding the E-CAN film, T g It has a shape memory property that returns to its original state without any fold marks simply by being placed at a temperature above this level.

[0196] T v After forming the shape at the above temperature, the shape is fixed by relieving the stress applied to the folded part. Also, T v Since the exchange reaction occurs at the above temperature, T v Shape fixing is performed at the above temperature, and T vSince the stress relaxation time is very long at that temperature, the process was conducted at 240°C, where the stress relaxation time is short.

[0197] As shown in Fig. 17, the shape memory characteristic was confirmed to return to its original state without significant damage even after the E-CAN film was folded into a difficult shape, such as a crane.

[0198] In addition, as shown in Fig. 18, since the E-CAN sample has dynamic coupling, T, where the exchange reaction occurs after fixing the shape v Shape reconfigurability was demonstrated by inducing stress relaxation at the above temperatures. After fixing it in a pinwheel shape and then unfolding it again, T g The shape reconfigurability characteristic was confirmed by placing E-CAN-R2.3 on the above and returning it to a pinwheel shape.

[0199] Therefore, the present invention is characterized by features that differentiate it from conventional thermosetting polymer epoxy materials, which are unable to fix their shape because only permanent crosslinking exists and stress relief due to exchange reactions is impossible.

[0200]

[0201] Although a fully recyclable double dynamic bond-based high-strength epoxy polymer and a method for manufacturing the same according to a preferred embodiment of the present invention have been described as above, those skilled in the art will understand that this is merely an example and that various changes and modifications are possible within the scope of the technical spirit of the present invention.

Claims

1. A first monomer comprising two or more epoxy groups; A second monomer of an aliphatic carboxylic acid containing sulfur; and Includes a third monomer that acts as a catalyst; and A fully recyclable high-strength epoxy polymer characterized by dual dynamic reactions by a third monomer that facilitates the reaction between the epoxy ring of the first monomer and the aliphatic carboxylic acid ends of the second monomer.

2. In Paragraph 1, The above dual dynamic reactions are, A fully recyclable high-strength epoxy polymer characterized by including transesterifications and disulfide metathesis reactions.

3. In Paragraph 1, The above first monomer is, A fully recyclable high-strength epoxy polymer characterized by comprising one or more of the group consisting of bisphenol-based, aminophenol-based, siloxane-based, and alicyclic epoxy resins.

4. In Paragraph 1, The above second monomer is, A fully recyclable high-strength epoxy polymer characterized by selecting any one of 2,2'-dithiodibenzoic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid, 5,5'-dithiobis(2-nitrobenzoic acid), 6,6'-dithiodinicotinic acid, DL-homocysteine, penicillamine disulfide, and L-glutathione oxidized.

5. In Paragraph 1, The above third monomer is, A fully recyclable high-strength epoxy polymer characterized by being 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

6. In Paragraph 1, The above epoxy polymer is, A fully recyclable high-strength epoxy polymer characterized by containing, for every 1 mole of the second monomer (DTDA), the first monomer (DGEBA) and the third monomer (TBD) in a molar ratio of 1 to 2.5 : 0.02 to 0.04, respectively.

7. In Paragraph 1, The above epoxy polymer is, A fully recyclable high-strength epoxy polymer characterized by being reusable after decomposing when heated and immersed in an aqueous solution of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

8. In Paragraph 1, The above epoxy polymer is, Glass transition temperature (T g A fully recyclable high-strength epoxy polymer characterized by having shape memory properties that return to its original shape at temperatures above ) 9. A step of preparing a transparent solution by mixing and heating the first monomer and the second monomer; A step of preparing a mixture by mixing a third monomer into the above transparent solution and stirring; The step of pouring the above mixture into a mold and heating to pre-cure it; and A method for manufacturing a fully recyclable high-strength epoxy polymer, characterized by including the step of heating the above-mentioned pre-cured mixture under vacuum to perform main curing.

10. In Paragraph 9, A method for manufacturing a fully recyclable high-strength epoxy polymer, characterized by mixing the first monomer (DGEBA) in a ratio of 1 to 2.5 moles to 1 mole of the second monomer (DTDA) in the step of preparing the transparent solution, and mixing the third monomer (TBD) in a molar ratio of 0.02 to 0.04 in the step of preparing the mixture.

11. In Paragraph 9, The above first monomer is, A method for manufacturing a fully recyclable high-strength epoxy polymer characterized by comprising one or more of the group consisting of bisphenol-based, aminophenol-based, siloxane-based, and alicyclic epoxy resins.

12. In Paragraph 9, The above second monomer is, A method for manufacturing a fully recyclable high-strength epoxy polymer characterized by selecting any one of 2,2'-dithiodibenzoic acid, 3,3'-dithiodipropionic acid, 4,4'-dithiodibutyric acid, 5,5'-dithiobis(2-nitrobenzoic acid), 6,6'-dithiodinicotinic acid, DL-homocysteine, penicillamine disulfide, and L-glutathione oxidized.

13. In Paragraph 9, The above third monomer is, A method for manufacturing a fully recyclable high-strength epoxy polymer characterized by being 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

14. In Paragraph 9, In the above step of preparing the transparent solution, A method for manufacturing a fully recyclable high-strength epoxy polymer characterized by heating to 170 to 190℃.

15. In Paragraph 9, In the above preliminary curing step, A method for manufacturing a fully recyclable high-strength epoxy polymer characterized by heating and curing at a temperature of 170 to 190°C for 45 to 75 minutes.

16. In Paragraph 9, In the above curing step, A method for manufacturing a fully recyclable high-strength epoxy polymer characterized by heating and curing at a vacuum pump pressure of 0 to 0.1 MPa at a temperature of 170 to 190°C for 3 to 10 hours.

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