Biomaterial-based vitrimer composite material that can be recycled and reprocessed and has self-healing and stress-responsive properties, and method for manufacturing same

Abstract

The present disclosure relates to a biomaterial-based vitrimer composite material that can be recycled and reprocessed and has self-healing and stress-responsive properties, and a method for manufacturing same. Specifically, the vitrimer composite material according to the present disclosure can exhibit excellent self-healing, reprocessing, and recycling characteristics of the biomaterial-based vitrimer while continuously exhibiting stress-responsive characteristics of spiropyran.

Description

A biomaterial-based vitrifier composite material that is recyclable and reprocessable and has self-healing and stress-sensitive properties, and a method for manufacturing the same

[0001] The present disclosure relates to a biomaterial-based vitrifier composite material that is recyclable and reprocessable and has self-healing and stress-sensitive properties, and a method for manufacturing the same.

[0002] Cross-reference to related applications

[0003] This application claims priority to Republic of Korea Patent Application No. 10-2024-0055301, filed April 25, 2024, the entire contents of which are incorporated herein by reference.

[0004] [Description of Nationally Supported Research and Development]

[0005] This study was conducted under the supervision of the Korea Institute of Science and Technology (KIST), with the support of the Ministry of Trade, Industry and Energy's Strategic Core Material Self-reliance Technology Development Project (Development of core material technology for localization of latent hardener for low-temperature fast-curing and securing mass production of ACF for rigid (COG)-flexible (COP), Project Identification Number: 1415186142), the Ministry of Science and ICT's Nanomaterial Technology Development Project (Development of fully recyclable composite materials and eco-friendly recycling technology using dynamically bonded cross-linked polymers based on multiple networks, Project Identification Number: 1711188974), and the National Research Council of Science and Technology Research Operation Expense Support (Major Project Expense) Project (Development of high heat-resistant and high flame-retardant materials through upcycling of industrial waste resources and preliminary research on application technology for building insulation materials, Project Identification Number: 1711201893).

[0006] Vitrimer material is a material that corresponds to the interface between thermosetting resin and thermoplastic resin. It is a thermosetting resin that forms a stable network through covalent bonding when the temperature is low, but when the temperature is high, it is capable of dynamic cross-linking exchange reaction, has shape recovery, reduces viscosity, and is capable of remolding, reprocessing, and self-healing.

[0007] Spiropyran is a molecular sensor that exhibits color or fluorescence changes in response to force. This allows the creation of self-diagnostic materials that can autonomously detect deformation, stress, and damage in organic or inorganic materials. Specifically, when a spiropyran molecule is subjected to force, the CO bond is selectively cleaved, converting spiropyran to merocyanine, which is accompanied by changes in color and fluorescence properties. While spiropyran is faintly yellow (or colorless) and non-fluorescent, merocyanine is blue (or purple) and exhibits strong fluorescence in the 550–700 nm wavelength range. The distinct optical properties of spiropyran and merocyanine are readily recognizable with the naked eye and offer the advantage of quantitative detection using optical equipment. Furthermore, merocyanine is reactive and reverts to spiropyran when exposed to visible light, allowing for semi-permanent, reusable use. Due to these properties of spiropyran, self-diagnostic materials using spiropyran have high application potential in fields such as stress / strain sensors, damage detection, and artificial skin, and are receiving much attention.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 1) Republic of Korea Patent Publication No. 10-2023-0055727

[0011] The present disclosure aims to provide a vitrimer composite material that exhibits the stress-sensitive properties of spiropyran while also exhibiting excellent self-healing, reprocessing, and recycling properties of vitrimer.

[0012] In order to achieve the above-mentioned object, one embodiment of the present invention provides a vitrimer composite material including a vitrimer including an epoxy resin and an organic acid; and a spiropyran bead including spiropyran and a polymer covalently bonded to the spiropyran.

[0013] In addition, another embodiment of the present invention provides a method for producing a vitrimer composite material, including the steps of: polymerizing an epoxy resin and an organic acid under a reaction catalyst to produce a vitrimer through a ring-opening reaction between an epoxy group of the epoxy resin and a carboxyl group of the organic acid; dispersing and reacting spiropyran and a polymer in an organic solvent to produce spherical spiropyran beads in which the polymer is covalently bonded to the spiropyran; and mixing the vitrimer and the spiropyran beads to produce a vitrimer composite material.

[0014] The vitriol composite material according to the present disclosure may exhibit the stress-sensitive properties of spiropyran while also exhibiting excellent self-healing, reprocessing, and recycling properties of biomaterial-based vitriol.

[0015] Figure 1 shows images of spiropyran beads (SP beads) according to a comparative example (left) and spiropyran beads (SP bead GMA 10%) according to an embodiment (right), respectively.

[0016] FIG. 2a and FIG. 2b show images of spiropyran beads (SP beads) according to a comparative example and spiropyran beads (SP bead GMA 10%) according to an embodiment (FIG. 2a) and the results of comparing infrared peaks of spiropyran beads (FIG. 2b), respectively.

[0017] Figures 3a and 3b show the results of confirming the relaxation modulus (Figure 3a) and stress relaxation time (Figure 3b) of a bitrimer composite material according to one embodiment.

[0018] Figure 4 shows the results of confirming the shape memory characteristics of a bitrimer composite material according to one embodiment through dynamic thermomechanical (DMA) analysis.

[0019] Figure 5 shows the results of visually confirming the shape memory characteristics of a bitrimer composite material according to one embodiment.

[0020] FIGS. 6A to 6C illustrate the results of confirming the self-healing (FIG. 6A), reprocessing (FIG. 6B), and recycling (FIG. 6C) characteristics of a bitrimer composite material according to one embodiment.

[0021] Figure 7 shows the results of confirming the stability of a bitrimer composite material according to one embodiment.

[0022] FIG. 8a and FIG. 8b show the results of observing color changes due to stress in tension (FIG. 8a) and compression (FIG. 8b) of a bitrimer composite material according to one embodiment.

[0023] Figures 9a and 9b show the tensile test results (Figure 9a) and stress-strain curves (Figure 9b) of the bitrimer composite materials according to the examples and comparative examples.

[0024] Hereinafter, the present invention will be described in detail.

[0025] In one aspect, the present invention comprises a vitrifier comprising an epoxy resin and an organic acid; and

[0026] It may be related to a vitrimer composite material including spiropyran beads including spiropyran and a polymer covalently bonded to the spiropyran.

[0027] In one embodiment, the epoxy may be at least one selected from bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) diglycidyl ether, 1,4-butandiol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, N,N-diglycidyl-4-glycidyloxyaniline, and 4,4'-methylenebis(N,N-diglycidylaniline).

[0028] In one embodiment, the organic acid may be a carboxylic acid.

[0029] In one embodiment, the organic acid may be one or more selected from citric acid, fumaric acid, L-malic acid, oxaloacetate, and succinic acid.

[0030] In one embodiment, the bitrimer may be cross-linked by an epoxy group of the epoxy resin and a carboxyl group of the organic acid through an epoxy group ring-opening reaction under a reaction catalyst.

[0031] In one embodiment, the reaction catalyst may be at least one selected from zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and triphenylphosphine.

[0032] In one embodiment, the epoxy group of the epoxy resin and the carboxyl group of the organic acid may react in a ratio of 1:0.1 to 3 (epoxy group: carboxyl group). Specifically, the reaction ratio (epoxy group: carboxyl group) of the epoxy group of the epoxy resin and the carboxyl group of the organic acid is 1:0.1 to 3, 1:0.1 to 2.5, 1:0.1 to 2, 1:0.1 to 1.5, 1:0.1 to 1, 1:0.1 to 0.8, 1:0.1 to 0.6, 1:0.1 to 0.4, 1:0.1 to 0.3, 1:0.2 to 2.5, 1:0.2 to 2, 1:0.2 to 1.5, 1:0.2 to 1, 1:0.2 to 0.8, 1:0.2 to 0.6, 1:0.2 to 0.4, 1:0.2 to 0.3, 1: It can be 0.3 to 2, 1: 0.3 to 1.5, 1: 0.3 to 1, 1: 0.3 to 0.8, 1: 0.3 to 0.5 or 1: 0.3 to 0.4.

[0033] In one embodiment, the covalent bond formed between the spiropyran and the polymer may be a bond between one or more functional groups of the hydroxyl group, bisalkene group, acrylic group, and bromine group of the spiropyran and one or more functional groups of the isocyanate group, carboxyl group, vinyl group, and acrylic group of the polymer.

[0034] In one embodiment, the spiropyran beads may be manufactured by emulsion polymerization, micelle polymerization, dispersion polymerization, suspension polymerization, or microfluidic polymerization of a mixture comprising the spiropyran, the polymer, and the organic solvent, and preferably manufactured by micelle polymerization. In this case, the mixture may further include a stabilizer.

[0035] In one embodiment, the polymer may be at least one selected from the group consisting of polydimethylsiloxane, polyurethane, polycaprolactone, polyamide, polyimide, polystyrene, polyacrylate, polyaniline, epoxy, silicone, cellulose, and natural rubber.

[0036] In one embodiment, the polymer may be an epoxy.

[0037] In one embodiment, the weight ratio of the spiropyran and the polymer may be 1:3 to 1000. Specifically, the weight ratio of the spiropyran and the polymer (spiropyran: polymer) is 1:3 or more, 1:10 or more, 1:20 or more, 1:30 or more, 1:40 or more, 1:50 or more, 1:60 or more, 1:70 or more, 1:80 or more, 1:90 or more, 1:100 or more, 1:150 or more, 1:200 or more, 1:250 or more, 1:300 or more, 1:350 or more, 1:400 or more, 1:450 or more, 1:500 or more, 1:550 or more, 1:600 ​​or more, 1:650 or more, 1:700 or more, 1:750 or more, 1:800 or more, 1: It may be 850 or more, 1:900 or more or 1:950 or more, and further, the weight ratio of the spiropyran and the polymer (spiropyran: polymer) may be 1:1000 or less, 1:950 or less, 1:900 or less, 1:850 or less, 1:800 or less, 1:750 or less, 1:700 or less, 1:650 or less, 1:600 ​​or less, 1:550 or less, 1:500 or less, 1:450 or less, 1:400 or less, 1:350 or less, 1:300 or less, 1:250 or less, 1:200 or less, 1:150 or less, 1:100 or less, 1:90 or less, 1:80 or less, 1:70 or less, It can be 1:60 or less, 1:50 or less, 1:40 or less, 1:30 or less, 1:20 or less, or 1:10 or less.

[0038] In one embodiment, the spiropyran beads may be spherical in shape with a diameter of 10 nm to 1 mm. Specifically, the diameter of the spiropyran beads is 10 nm or more, 50 nm or more, 100 nm or more, 200 nm or more, 300 nm or more, 400 nm or more, 500 nm or more, 600 nm or more, 700 nm or more, 800 nm or more, 900 nm or more, 0.001 mm or more, 0.002 mm or more, 0.003 mm or more, 0.004 mm or more, 0.005 mm or more, 0.006 mm or more, 0.007 mm or more, 0.008 mm or more, 0.009 mm or more, 0.01 mm or more, 0.02 mm or more, 0.03 mm or more, 0.04 mm or more, 0.05 mm or more, 0.06 mm or more, 0.07 mm or more, 0.08 mm or more, 0.09 mm or more, 0.1 mm or more, 0.2 mm or more, 0.3 mm or more, 0.4 mm or more, 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, or 0.9 mm or more, and further, the diameter of the spiropyran beads may be 1 mm or less, 0.9 mm or less, 0.8 mm or less, 0.7 mm or less, 0.6 mm or less, 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, 0.1 mm or less, 0.09 mm or less, 0.08 mm or less, 0.07 mm or less, 0.06 mm or less, 0.05 mm or less, 0.04 mm or less, 0.03 mm or less, 0.02 mm or less, 0.01 mm or less, 0.009 mm or less, 0.008 mm or less, 0.007 mm or less, 0.006 It may be less than or equal to mm, less than or equal to 0.005 mm, less than or equal to 0.004 mm, less than or equal to 0.003 mm, less than or equal to 0.002 mm, less than or equal to 0.001 mm, less than or equal to 900 nm, less than or equal to 800 nm, less than or equal to 700 nm, less than or equal to 600 nm, less than or equal to 500 nm, less than or equal to 400 nm, less than or equal to 300 nm, less than or equal to 200 nm, less than or equal to 100 nm, or less than or equal to 50 nm.

[0039] In one embodiment, the spiropyran beads may have optical properties that change with force, deformation, and damage.

[0040] In one embodiment, the change in optical properties may be a change in color or a change in fluorescent properties.

[0041] In one embodiment, the optical properties may be measured using one or more selected from the group consisting of the naked eye, an RGB sensor, a fluorescence camera, a spectrometer, and an optical filter.

[0042] In one embodiment, the measurement may be a measurement over a region of interest or over the entire material.

[0043] In one embodiment, the spiropyran beads may further include additives for performance enhancement and synthesis control. In one embodiment, the additives may be one or more selected from silica, alumina, titanium dioxide, talc, mercury, citrate, palm oil, starch, and sugar.

[0044] In one embodiment, the weight ratio of the bitrimer and the spiropyran beads (bitrimer: spiropyran beads) may be 100:0.1 to 5. Specifically, the weight ratio of the vitrimer and the spiropyran beads (vitrimer: spiropyran beads) is 100:0.1 to 5, 100:0.1 to 4.5, 100:0.1 to 4, 100:0.1 to 3.5, 100:0.1 to 3, 100:0.1 to 2.5, 100:0.1 to 2, 100:0.3 to 5, 100:0.3 to 4.5, 100:0.3 to 4, 100:0.3 to 3.5, 100:0.3 to 3, 100:0.3 to 2.5, 100:0.3 to 2, 100:0.4 to 5, 100: 0.4 to 4.5, 100: 0.4 to 4, 100: 0.4 to 3.5, 100: 0.4 to 3, 100: 0.4 to 2.5, 100: 0.4 to 2, 100: 0.6 to 5, 100: 0.6 to 4.5, 100: 0.6 to 4, 100: 0.6 to 3.5, 100: 0.6 to 3, 100: 0.6 to 2.5, 100: 0.6 to 2, 100: 0.8 to 5, 100: 0.8 to 4.5, 100: 0.8 to 4, 100: 0.8 to 3.5, 100: 0.8 to 3, 100:0.8 to 2.5, 100:0.8 to 2, 100:1 to 5, 100:1 to 4.5, 100:1 to, 100:1 to 4, 100:1 to 3.5, 100:1 to 3, 100:1 to 2.5, 100:1 to 2, 100:2 to 5, 100:2 to 4.5, 100:2 to 4, 100:2 to 3.5, 100:2 to 3 or 100:2 to 2.5. In one embodiment, the spiropyran beads may be 0.It may be included in an amount of 1 to 5 wt%. Specifically, the spiropyran beads are present in an amount of 0.1 wt% or more, 0.2 wt% or more, 0.3 wt% or more, 0.4 wt% or more, 0.5 wt% or more, 0.6 wt% or more, 0.7 wt% or more, 0.8 wt% or more, 0.9 wt% or more, 1 wt% or more, 1.1 wt% or more, 1.2 wt% or more, 1.3 wt% or more, 1.4 wt% or more, 1.5 wt% or more, 1.6 wt% or more, 1.7 wt% or more, 1.8 wt% or more, 1.9 wt% or more, 2 wt% or more, 2.1 wt% or more, 2.2 wt% or more, 2.3 wt% or more, 2.4 wt% or more, 2.5 wt% or more, 2.6 wt% or more, 2.7 wt% or more, 2.8 wt% or more, 2.9 wt% or more, 3 wt% or more, 3.5 wt% or more, or 4 wt% or more, and further, the spiropyran beads may be included in an amount of 5 wt% or less, 4 wt% or less, 3 wt% or less, 2.9 wt% or less, 2.8 wt% or less, 2.7 wt% or less, 2.6 wt% or less, 2.5 wt% or less, 2.4 wt% or less, 2.3 wt% or less, 2.2 wt% or less, 2.1 wt% or less, 2 wt% or less, 1.9 wt% or less, 1.8 wt% or less, 1.7 wt% or less, 1.6 wt% or less, 1.5 wt% or less, 1.4 wt% or less, 1.3 wt% or less, 1.2 wt% or less, 1.1 wt% or less, 1 wt% or less, 0.9 wt% or less, 0.8 wt% or less, or It may be included in an amount of 0.7 wt% or less.

[0045] In another aspect, the present invention may relate to a method for producing a vitrimer composite material, comprising the steps of: polymerizing an epoxy resin and an organic acid under a reaction catalyst to produce a vitrimer through a ring-opening reaction between an epoxy group of the epoxy resin and a carboxyl group of the organic acid; dispersing and reacting spiropyran and a polymer in an organic solvent to produce spherical spiropyran beads in which the polymer is covalently bonded to the spiropyran; and mixing the vitrimer and the spiropyran beads to produce a vitrimer composite material.

[0046] In one embodiment, the epoxy group ring-opening reaction in the step of preparing the bitrimer may be performed at a temperature of 100 to 200°C for 1 to 24 hours. Specifically, the epoxy group ring-opening reaction may be performed at a temperature of 100°C or higher, 110°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, or 190°C or higher, and further, the epoxy group ring-opening reaction may be performed at a temperature of 200°C or lower, 190°C or lower, 180°C or lower, 170°C or lower, 160°C or lower, 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower. More specifically, the epoxy group ring-opening reaction may be performed for 1 hour or more, 4 hours or more, 8 hours or more, 12 hours or more, 16 hours or more, or 20 hours or more, and further, the epoxy group ring-opening reaction may be performed for 24 hours or less, 20 hours or less, 16 hours or less, 12 hours or less, 8 hours or less, or 4 hours or less.

[0047] In one embodiment, the reaction in the step of manufacturing the spiropyran beads can be performed by emulsion polymerization, micelle polymerization, dispersion polymerization, suspension polymerization or microfluidic polymerization.

[0048] In one embodiment, the organic solvent may be at least one selected from xylene, benzene, toluene, and acetone.

[0049] In one embodiment, the reaction in the step of manufacturing the spiropyran beads may be performed at a temperature of 40 to 80°C for 12 to 36 hours. Specifically, the reaction may be performed at a temperature of 40°C or higher, 50°C or higher, 60°C or higher, or 70°C or higher, and further, the reaction may be performed at a temperature of 80°C or lower, 70°C or lower, 60°C or lower, or 50°C or lower. More specifically, the reaction may be performed for 12 hours or higher, 16 hours or higher, 20 hours or higher, 24 hours or higher, 28 hours or higher, or 32 hours or higher, and further, the reaction may be performed for 36 hours or lower, 32 hours or lower, 28 hours or lower, 24 hours or lower, 20 hours or lower, or 16 hours or lower.

[0050] The above epoxy, organic acid, spiropyran and polymer are described in detail above and are therefore omitted below.

[0051]

[0052] The present invention may provide, as an example, the following embodiments.

[0053] The first embodiment can provide a vitrimer composite material including a vitrimer including an epoxy resin and an organic acid; and a spiropyran bead including spiropyran and a polymer covalently bonded to the spiropyran.

[0054] A second embodiment can provide a vitrimer composite material, wherein, in the first embodiment, the epoxy is at least one selected from bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) diglycidyl ether, 1,4-butandiol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, N,N-diglycidyl-4-glycidyloxyaniline, and 4,4'-methylenebis(N,N-diglycidylaniline).

[0055] A third embodiment can provide a vitriol composite material, wherein in at least one of the first embodiment and the second embodiment, the organic acid is at least one selected from citric acid, fumaric acid, L-malic acid, oxaloacetate, and succinic acid.

[0056] A fourth embodiment can provide a vitriol composite material in which, in one or more of the first to third embodiments, the vitriol is cross-linked by an epoxy group of the epoxy resin and a carboxyl group of the organic acid through an epoxy group ring-opening reaction under a reaction catalyst.

[0057] A fifth embodiment can provide a vitrimer composite material, wherein in at least one of the first to fourth embodiments, the reaction catalyst is at least one selected from zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and triphenylphosphine.

[0058] The sixth embodiment can provide a vitriol composite material in which the epoxy group of the epoxy resin and the carboxyl group of the organic acid react at a ratio of 1:0.1 to 3 in at least one of the first to fifth embodiments.

[0059] The seventh embodiment can provide a vitrimer composite material, wherein in at least one of the first to sixth embodiments, the polymer is at least one selected from the group consisting of polydimethylsiloxane, polyurethane, polycaprolactone, polyamide, polyimide, polystyrene, polyacrylate, polyaniline, epoxy, silicone, cellulose, and natural rubber.

[0060] The eighth embodiment can provide a vitrimer composite material in which the weight ratio of the spiropyran and the polymer is 1:3 to 1000 in at least one of the first to seventh embodiments.

[0061] The ninth embodiment can provide a vitrimer composite material in which, in one or more of the first to eighth embodiments, the spiropyran beads are spherical in shape with a diameter of 10 nm to 1 mm.

[0062] The tenth embodiment can provide a vitriol composite material according to at least one of the first to ninth embodiments, wherein the polymer is an epoxy.

[0063] The eleventh embodiment can provide a vitriol composite material in which the spiropyran beads, in one or more of the first to tenth embodiments, have optical properties that change due to force, deformation, and damage.

[0064] The 12th embodiment can provide a vitrimer composite material in which the weight ratio of the vitrimer and the spiropyran beads is 100:0.1 to 5 in at least one of the first to eleventh embodiments.

[0065] The 13th embodiment comprises a step of manufacturing a bitrimer by polymerizing an epoxy resin and an organic acid under a reaction catalyst to cause a ring-opening reaction between an epoxy group of the epoxy resin and a carboxyl group of the organic acid;

[0066] A step of dispersing and reacting spiropyran and a polymer in an organic solvent to produce a spherical spiropyran bead in which the polymer is covalently bonded to the spiropyran; and

[0067] A method for producing a vitrimer composite material can be provided, including a step of producing a vitrimer composite material by mixing the above vitrimer and the above spiropyran beads.

[0068] The 14th embodiment can provide a method for producing a vitrimer composite material, wherein, in the 13th embodiment, the epoxy is at least one selected from bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) diglycidyl ether, 1,4-butandiol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, N,N-diglycidyl-4-glycidyloxyaniline, and 4,4'-methylenebis(N,N-diglycidylaniline).

[0069] The 15th embodiment can provide a method for producing a vitriol composite material, wherein in at least one of the 13th embodiment and the 14th embodiment, the organic acid is at least one selected from citric acid, fumaric acid, L-malic acid, oxaloacetate, and succinic acid.

[0070] The 16th embodiment can provide a method for producing a vitrimer composite material, wherein in at least one of the 13th to 15th embodiments, the reaction catalyst is at least one selected from zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and triphenylphosphine.

[0071] The 17th embodiment can provide a method for producing a vitriol composite material, wherein the epoxy group of the epoxy resin and the carboxyl group of the organic acid react at a ratio of 1:0.1 to 3 in at least one of the 13th to 16th embodiments.

[0072] The 18th embodiment can provide a method for producing a vitrimer composite material, wherein in one or more of the 13th to 17th embodiments, the weight ratio of the spiropyran and the polymer is 1:3 to 1000.

[0073] The 19th embodiment can provide a method for producing a vitriol composite material, wherein in one or more of the 13th to 18th embodiments, the polymer is an epoxy.

[0074] The 20th embodiment can provide a method for producing a vitrimer composite material, wherein in one or more of the 13th to 19th embodiments, the vitrimer and the spiropyran beads are mixed in a weight ratio of 100:0.1 to 5.

[0075]

[0076] Hereinafter, the present invention will be described in more detail through examples and test examples. However, these examples and test examples are provided merely to facilitate understanding of the present invention, and the scope of the present invention is not limited to these examples and test examples. Modifications, substitutions, and insertions commonly known in the art may be performed, and such modifications are also included within the scope of the present invention.

[0077]

[0078] Examples and Test Examples

[0079] The raw materials used are as follows:

[0080] Citric acid (Merck)

[0081] zinc acetylacetonate hydrate (Zn(acac)2) (Merck)

[0082] Tetrahydrofuran (THF, anhydrous, >99.9%, inhibitor-free) (Merck)

[0083] Epoxy resin (YD-115) (Kukdo Chemical)

[0084] PDMS precursor (Sylgard 184) (Dow Corning, USA)

[0085] Glycidyl methacrylate (GMA) (Merck)

[0086] Manufacturing Example 1. Manufacturing of spiropyran beads (SP beads)

[0087] Spiropyran beads were prepared using the dispersion polymerization method as follows: 150 mg of bis-alkene-functionalized spiropyran was placed in a 70 mL glass vial and completely dissolved in 5 mL of xylene. 10 g of Sylgard 184 (base to curing agent ratio 10:1, Dow Corning, USA) and 30 mL of a surfactant solution (5 wt% sodium dodecyl sulfate dissolved in water) were then added. The mixture was then stirred for 5 minutes using a vortex mixer (Vortex Genie 2, Scientific Industries Inc., USA). To ensure that the spiropyran beads were uniform in size, the mixture was passed through a microemulsifying needle (18G) using a syringe several times, then poured into a 250 mL round-bottom flask containing 200 mL of the aforementioned surfactant solution. After stabilizing for 5 minutes, the polymerization reaction was performed at 60°C for 24 hours. The synthesized spiropyran beads (SP beads) were washed with acetone and vacuum-dried at room temperature for 24 hours. Images of the manufactured spiropyran beads (SP beads) are shown in Fig. 1 (left drawing) and Fig. 2a (upper drawing).

[0088]

[0089] Manufacturing Example 2. Manufacturing of epoxy-spiropyran beads (Epoxy SP beads or SP beads GMA 10%)

[0090] Epoxy-spiropyran beads were prepared as follows: 150 mg of bis-alkene-functionalized spiropyran was placed in a 70 mL glass vial and completely dissolved in 5 mL of xylene. Then, 10 g of Sylgard 184 (base to curing agent ratio 10:1, Dow Corning, USA) as a functionalizing agent and 1 g of GMA were mixed with 30 mL of sodium dodecyl sulfate (SDS) solution (5 wt% in water), and the mixture was added to the vial containing the dissolved spiropyran. The mixed solution was uniformly mixed using a vortex mixer (Vortex Genie 2, Scientific Industries Inc., USA). To ensure uniform size, the mixture was passed through a microemulsifying needle (18G) several times, then poured into a 250 mL round-bottom flask containing 200 mL of the aforementioned 5 wt% SDS solution, and then stabilized for 5 minutes before polymerization was performed at 60°C for 24 hours. The synthesized epoxy-spiropyran beads (SP bead GMA 10%) were washed with acetone and vacuum-dried at room temperature for 24 hours. Images of the manufactured epoxy-spiropyran beads (SP bead GMA 10%) are shown in Fig. 1 (right drawing) and Fig. 2a (bottom drawing).

[0091]

[0092] Manufacturing Example 3. Manufacturing of PDMS-spiropyran beads (PDMS SP beads)

[0093] PDMS-spiropyran beads were prepared in the same manner as the epoxy-spiropyran beads in Manufacturing Example 2, except that 1 g of PDMS was used instead of 1 g of GMA.

[0094]

[0095] Manufacturing Example 4. Manufacturing of Vitrimmer

[0096] 1.033 g of citric acid and 0.44 g of zinc acetylacetonate hydrate (Zn(acac)2) were placed in a vial containing 2 mL of THF and mixed homogeneously by ultrasonication. Zn(acac)2 was added as a transesterification catalyst. The above mixture solution and 10 g of epoxy resin (YD-115) were placed in a 50 mL beaker and stirred on a hot plate at 60°C for 1 hour. The viscous mixture resulting from the partial epoxy-carboxylic reaction was transferred to a Teflon-coated mold and placed on a 75°C hot plate for 2 hours to remove the THF solvent, and then placed in a 75°C vacuum oven for 2 hours. Then, the vitrimmer was prepared by reacting in the oven at 140°C for 12 hours.

[0097]

[0098] Example 1. Preparation of epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite material

[0099] 0.22 g of the epoxy-spiropyran beads manufactured in the above Manufacturing Example 2 were placed in a 20 mL vial with 3 mL of THF and dissolved and dispersed through ultrasonic treatment. 1.033 g of citric acid and 0.44 g of zinc acetylacetonate hydrate (Zn(acac)2) were placed in another vial containing 2 mL of THF and homogeneously mixed through ultrasonic treatment. At this time, Zn(acac)2 was added as a transesterification catalyst. The two solutions and 10 g of epoxy resin (YD-115) were placed in a 50 mL beaker and stirred on a hot plate at 60°C for 1 hour. The viscous mixture resulting from the partial epoxy-carboxylic acid reaction was transferred to a Teflon-coated mold, placed on a hot plate at 75°C for 2 hours to remove the THF solvent, and then placed in a vacuum oven at 75°C for 2 hours. Then, the mixture was reacted in the oven at 140°C for 12 hours to produce a cross-linked vitrimer composite (epoxy-spiropyran beads / vitrimer).

[0100]

[0101] Example 2. Preparation of PDMS-spiropyran bead (PDMS SP bead) / bitrimer composite material

[0102] A PDMS-spiropyran bead / bitrimer composite material was prepared in the same manner as in Example 1, except that 0.22 g of the PDMS-spiropyran beads of Preparation Example 3 was used instead of the epoxy-spiropyran beads.

[0103]

[0104] Comparative Example 1. Manufacturing of Spiropyran Bead (SP Bead) / Vitrimer Composite Material

[0105] A spiropyran bead / bitrimer composite material was manufactured in the same manner as in Example 1, except that 0.22 g of the spiropyran beads of Preparation Example 1 was used instead of the epoxy-spiropyran beads.

[0106]

[0107] Comparative Example 2. Manufacturing of Spiropyran Powder (SP Powder) / Vitrimer Composite Material

[0108] A spiropyran powder / bitrimer composite was prepared in the same manner as in Example 1, except that 0.011 g of regular spiropyran powder was used instead of the epoxy-spiropyran beads.

[0109]

[0110] Test Example 1. Confirmation of infrared peaks of spiropyran beads

[0111] The infrared peaks of the spiropyran beads (SP beads) of Manufacturing Example 1 and the epoxy-spiropyran beads (SP bead GMA 10%) of Manufacturing Example 2 were measured using a Nicolet iS10 FTIR spectrometer (Thermo Fisher Scientific, USA) (attenuated total reflectance (ATR) mode, 64 scans, 4,000 to 500 cm -1 ) was used for measurement, and the results are shown in Fig. 2b. From the results in Fig. 2b, in the case of the spiropyran beads of Manufacturing Example 1 in which an epoxy group was not introduced into the beads, the peak of the C=O group did not appear, whereas in the case of Manufacturing Example 2, the C=O peak appeared clearly, confirming that the epoxy group was well introduced into the spiropyran beads.

[0112]

[0113] Test Example 2. Confirmation of the vitrimeric and shape memory properties of a vitrimer composite material.

[0114] The vitrimeric properties (relaxation modulus, stress relaxation time) and shape memory properties of the epoxy-spiropyran bead (SP bead GMA 10%) / vitrimer composite of Example 1 were investigated. Specifically, the temperature-dependent thermodynamic properties in tension film mode were investigated through dynamic mechanical analysis (DMA, Q800, TA Instruments). All samples for DMA tests were cut into rectangular specimens measuring 20 mm (L) × 5 mm (W) × 1 mm (T). In multi-frequency strain mode, the specimens were equilibrated at 50°C and then subjected to a force of up to 0.01 MPa at a force rate of 0.005 MPa / min. Under elongation conditions, the samples were cooled to 0°C at a heating rate of 5°C / min and held isothermally for 20 min. Cyclic shape memory tests were performed repeatedly, and stress relaxation tests were performed on the same TMA tester in stress relaxation mode. The samples were equilibrated at different temperatures for 5 minutes, then subjected to a constant strain of 10%, and the elastic / plastic cycles were examined using the same DMA equipment. Repeated switching between controlled stress and stress relaxation modes was performed to observe the elastic and plastic cycles, respectively, and dilatometric tests were performed using the same DMA equipment in controlled force-tension mode. Each sample was measured at a heating rate of 3°C / min and stresses of 0.6, 1, 3, and 6 kPa while increasing the temperature from 30°C to 100°C. The results are shown in Figs. 3a, 3b, 4, and 5.

[0115] FIG. 3a shows the stress reduction according to temperature in the stress relaxation mode, through which it can be confirmed that the hydroxy ester group was exchanged through the transesterification reaction over time, and through the linear connection of the dots in FIG. 3b obtained through the result of FIG. 3a, it can be confirmed that the epoxy-spiropyran bead (SP bead GMA 10%) / vitrimer composite material according to an embodiment of the present invention shows a linear relationship between temperature and viscosity, similar to a glass body, and from this, it can be confirmed that it exhibits the vitrimer characteristics as they are.

[0116] From FIG. 4, it was confirmed that the epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite material according to one embodiment of the present invention repeatedly had shape memory properties (R f (Form fixation rate): 97.4%, R r (Shape recovery rate): 88.9%), which could also be confirmed by visual observation results in Fig. 5.

[0117]

[0118] Test Example 3. Verification of the self-healing, reprocessing, and recycling properties of Vitrimmer composite materials.

[0119] The self-healing, reprocessing, and recycling characteristics of the epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite of Example 1 were confirmed. Specifically, the self-healing test was performed by observing scratches using an optical microscope (OM, Nikon 50iPol, Nikon) and a scanning electron microscope (SEM, Nova NanoSEM 450) equipped with a temperature controller (Instec mK1000, Instec, Boulder). To confirm the self-healing characteristics, the surface of the same EB-V sample piece as in Test Example 2 was scratched with a blade and then heated at 130°C for 30 minutes. For the reprocessing test, the sample was cut into small pieces, stacked in a Teflon-coated mold with an imine film, and then compressed at 140°C under a pressure of 10 MPa for 20 minutes. For the recycling test, the EB-V sample pieces were immersed in a citric acid solution and left at 140°C for 24 hours. The results are shown in Figures 6a to 6c, respectively.

[0120] From the results of FIG. 6a, it was found that the epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite material according to one embodiment of the present invention exhibited excellent self-healing properties, as cracks almost disappeared simply by heating without applying pressure. Specifically, the initial width of the scratch was 41 μm, but it was confirmed that the width of the scratch was significantly reduced to 11 μm after self-healing by heating.

[0121] From the results of Fig. 6b, it was confirmed that reprocessing was successfully performed by heating pressure and that similar properties were exhibited to the existing ones. Through this, it was confirmed that the epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite material according to one embodiment of the present invention is capable of repeated testing due to its excellent reprocessing characteristics.

[0122] From the results of FIG. 6c, it was confirmed that the epoxy-spiropyran bead (SP bead GMA 10%) / vitrimer composite material according to one embodiment of the present invention was decomposed, and through this, it was found that a vitrimer composite material with similar properties could be manufactured through a reaction with an epoxy resin.

[0123] From the test results above, it was confirmed that the epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite material according to one embodiment of the present invention has excellent self-healing characteristics and excellent reprocessing characteristics, so that when the physical properties are significantly reduced after repeated use, a composite material with similar physical properties can be manufactured again through a recycling process of decomposition and resynthesis using citric acid, and thus the reprocessing and recycling characteristics are also excellent.

[0124]

[0125] Test Example 4. Stability Verification of Vitrimmer Composite Materials

[0126] The epoxy-spiropyran bead (SP bead GMA 10%) / bitrimer composite material of Example 1 was dispersed in various solvents (acetone, ethanol (EtOH), methanol (MeOH), tetrahydrofuran (THF), methylene chloride (MC), and water) and its stability was confirmed. The results are shown in Fig. 7.

[0127] From the results of FIG. 7, it was confirmed that the bitrimer composite material according to one embodiment of the present invention was stable for more than 96 hours in various solvents.

[0128]

[0129] Test Example 5. Confirmation of stress-sensitive characteristics of vitrifier composite materials.

[0130] The stress-sensitive characteristics of the epoxy-spiropyran bead (SP bead GMA 10%) / vitrimer composite of Example 1 were confirmed through tensile and compressive tests. Specifically, the tensile test was performed using Instron MODEL 5567A (UTM), and the measurement sample was prepared as a dog bone-shaped bar (tensile bar) with a size of 10 mm (L) x 2 mm (W) x 1 mm (T) (gauge length = 20 mm), and the color change was observed while performing the tensile test at 0.25 mm / sec. The compressive test was performed by applying pressure at 20 MPa for 1 second at room temperature (25°C) through hot compression, and the before and after were compared. The results are shown in FIGS. 8a and 8b. From the results of FIGS. 8a and 8b, it was confirmed that the vitrimer composite according to an embodiment of the present invention exhibited a color change due to stress.

[0131]

[0132] Test Example 6. Tensile Test of Vitrimmer Composite Materials

[0133] Tensile tests were performed on the vitrimer composite materials of Example 1, Comparative Examples 1 and 2, and the vitrimer of Manufacturing Example 4, respectively. The tensile test was performed in the same manner as in Test Example 5, and the results are shown in FIGS. 9a and 9b (S1: epoxy-spiropyran bead (SP bead GMA 10%) / vitrimer composite material, S2: spiropyran bead (SP bead) / vitrimer composite material, S3: spiropyran powder / vitrimer composite material, S4: vitrimer).

[0134] From the results of FIGS. 9a and 9b, it was confirmed that the mechanical properties of the vitrimer composites of Example 1 and Comparative Example 1 were significantly superior to those of the vitrimer composite of Comparative Example 2 and the vitrimer of Preparation Example 4, and in particular, in the case of the epoxy-spiropyran bead / vitrimer composite of Example 1, it was confirmed that the epoxy group of the spiropyran bead formed a covalent bond with the vitrimer, thereby increasing the interfacial properties between the beads and the vitrimer, thereby exhibiting superior mechanical properties.

Claims

1. A vitrifier containing an epoxy resin and an organic acid; and A vitrimer composite material comprising spiropyran beads comprising spiropyran and a polymer covalently bonded to the spiropyran.

2. In the first paragraph, the epoxy is at least one selected from bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) diglycidyl ether, 1,4-butandiol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, N,N-diglycidyl-4-glycidyloxyaniline, and 4,4'-methylenebis(N,N-diglycidylaniline), a vitrimer composite material.

3. A vitriol composite material in the first paragraph, wherein the organic acid is at least one selected from citric acid, fumaric acid, L-malic acid, oxaloacetate, and succinic acid.

4. In the first paragraph, the vitrimer is a vitrimer composite material in which the epoxy group of the epoxy resin and the carboxyl group of the organic acid are cross-linked by an epoxy group ring-opening reaction under a reaction catalyst.

5. In the fourth paragraph, the reaction catalyst is at least one selected from zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and triphenylphosphine, a vitrimer composite material.

6. A vitriol composite material in accordance with paragraph 4, wherein the epoxy group of the epoxy resin and the carboxyl group of the organic acid react at a ratio of 1:0.1 to 3.

7. In the first paragraph, the polymer is at least one selected from the group consisting of polydimethylsiloxane, polyurethane, polycaprolactone, polyamide, polyimide, polystyrene, polyacrylate, polyaniline, epoxy, silicone, cellulose, and natural rubber, a vitriol composite material.

8. A vitrimer composite material in the first paragraph, wherein the weight ratio of the spiropyran and the polymer is 1:3 to 1000.

9. A vitrimer composite material in the first paragraph, wherein the spiropyran beads are spherical in shape with a diameter of 10 nm to 1 mm.

10. A vitrimer composite material in claim 7, wherein the polymer is an epoxy.

11. A vitrimer composite material in accordance with claim 1, wherein the spiropyran beads have optical properties that change due to force, deformation, and damage.

12. A vitrimer composite material in the first paragraph, wherein the weight ratio of the vitrimer and the spiropyran beads is 100:0.1 to 5.

13. A step of manufacturing a bitrimer by polymerizing an epoxy resin and an organic acid under a reaction catalyst to cause a ring-opening reaction between an epoxy group of the epoxy resin and a carboxyl group of the organic acid; A step of dispersing and reacting spiropyran and a polymer in an organic solvent to produce a spherical spiropyran bead in which the polymer is covalently bonded to the spiropyran; and A method for producing a vitrimer composite material, comprising: a step of producing a vitrimer composite material by mixing the above vitrimer and the above spiropyran beads.

14. A method for producing a vitrimer composite material in claim 13, wherein the epoxy is at least one selected from bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) diglycidyl ether, 1,4-butandiol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, N,N-diglycidyl-4-glycidyloxyaniline, and 4,4'-methylenebis(N,N-diglycidylaniline).

15. A method for producing a vitriol composite material in claim 13, wherein the organic acid is at least one selected from citric acid, fumaric acid, L-malic acid, oxaloacetate, and succinic acid.

16. A method for producing a vitrimer composite material in claim 13, wherein the reaction catalyst is at least one selected from zinc acetylacetonate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, and triphenylphosphine.

17. A method for producing a vitriol composite material in claim 13, wherein the epoxy group of the epoxy resin and the carboxyl group of the organic acid react at a ratio of 1:0.1 to 3.

18. A method for producing a vitrimer composite material in claim 13, wherein the weight ratio of the spiropyran and the polymer is 1:3 to 1000.

19. A method for producing a vitriol composite material, wherein the polymer is an epoxy in the 13th paragraph.

20. A method for producing a vitrimer composite material, wherein the vitrimer and the spiropyran beads are mixed in a weight ratio of 100:0.1 to 5 in the 13th paragraph.

Images