Isotropic photocuring material and preparation method thereof

Abstract

The invention discloses an isotropic photocuring material and a preparation method thereof. The preparation method specifically comprises the following steps: (1) carrying out surface treatment on carbon fibers by adopting a chemical grafting modification method to obtain 4-vinylaniline modified carbon fibers; and (2) mixing epoxy acrylate, dicyclopentadiene acrylate and a photoinitiator, adding the 4-vinylaniline modified carbon fiber as a reinforcing phase, and carrying out photocuring 3D printing to obtain the isotropic photocuring material. A chemical grafting modification method is used for carrying out surface treatment on the fibers to obtain the 4-vinylaniline modified carbon fibers, so that chemical bonds exist between the modified fibers and a matrix, the interface bonding degree is higher, the tensile strength of a printed product is further improved, and the anisotropy is further reduced. By utilizing the combination effect between the modified carbon fiber and the resin matrix, the isotropy is realized while the mechanical property of the material is enhanced, and the practical application scene of the photocuring 3D printing product in industry is expected to be expanded.

Description

Technical Field

[0001] The invention relates to an isotropic light-curing material and a preparation method thereof, in particular to a photosensitive acrylate resin system enhanced by modifying carbon fibers with 4-vinylaniline, and belongs to the technical field of chemical industry and polymer materials. Background Art

[0002] Stereolithography 3D printing is a technology that uses computer-controlled visible light / ultraviolet light to trigger the polymerization of liquid photosensitive resin at specific locations on the printing platform to manufacture three-dimensional structures layer by layer. Depending on the control system, stereolithography 3D printing technologies include stereolithography (SLA), digital light processing (DLP), liquid crystal display (LCD), continuous liquid interface manufacturing (CLIP), and high area rapid printing (HARP). These printing technologies have the advantages of fast printing speed, high resolution, easy separation of printed structures and liquid resin, and reusable uncured resin.

[0003] However, the poor mechanical properties of the most commonly used photocurable 3D printing acrylic resins limit their practical applications in medical devices, electronic devices, automotive parts, aerospace, etc. The reason is, on the one hand, the structure of acrylics themselves; on the other hand, due to the layer-by-layer stacking molding method of photocurable 3D printing, the interlayer force is weak, which leads to anisotropy of the mechanical properties of the printed samples, especially the mechanical properties perpendicular to the printing direction are significantly lower than those in other directions.

[0004] How to improve the mechanical properties of photocurable 3D printing resins to meet a wider range of application needs has become a current research hotspot. Summary of the invention

[0005] Purpose of the invention: In view of the shortcomings of the prior art, the present invention provides an isotropic photocurable material and a preparation method thereof, and uses a chemical grafting modification method to perform surface treatment on the fiber to obtain 4-ethyleneaniline modified carbon fiber, so that a chemical bond exists between the modified fiber and the matrix, the interface bonding degree is higher, the tensile strength of the printed product is further improved, and the anisotropy is further reduced.

[0006] To achieve the above object, the technical solution adopted in the present invention is:

[0007] The first aspect of the present invention is to provide an isotropic photocurable material, which is a photosensitive resin in which 4-ethyleneaniline modified carbon fibers are distributed, wherein the content of the 4-ethyleneaniline modified carbon fibers is 1-3wt.% of the photosensitive resin, and the 4-ethyleneaniline modified carbon fibers are 4-ethyleneaniline grafted on the surface of the carbon fibers, wherein the tensile strength anisotropy of the isotropic photocurable material is less than 11.0%, and the elongation at break anisotropy is less than 8.5%.

[0008] The second aspect of the present invention is to provide the use of 4-ethyleneaniline modified carbon fiber in the preparation of isotropic photocurable material, wherein the isotropic photocurable material is the isotropic photocurable material as described above, and the 4-ethyleneaniline modified carbon fiber is carbon fiber with 4-ethyleneaniline grafted on the surface.

[0009] The third aspect of the present invention is to provide a method for preparing an isotropic photocurable material, the preparation method comprising the following steps:

[0010] (1) Using 4-vinylaniline as a raw material, a chemical grafting modification method is used to perform surface treatment on carbon fiber to obtain 4-vinylaniline modified carbon fiber;

[0011] (2) epoxy acrylate, dicyclopentadiene acrylate and a photoinitiator are mixed to obtain a photosensitive resin, and 4-vinylaniline modified carbon fiber is added as a reinforcing phase, wherein the content of the 4-vinylaniline modified carbon fiber is 1:10% of the photosensitive resin. 1- 3wt.% The material is evenly dispersed and an isotropic photocurable material is obtained by photocuring 3D printing.

[0012] The fourth aspect of the present invention is to provide the use of the isotropic photocurable material as described above or prepared by any of the methods described above in the field of medical equipment, electronic components, automotive parts or aerospace.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0014] 1. Carbon fiber CF is a new type of high-strength, high-modulus fiber with a carbon content of more than 95%. It is added to the photosensitive resin matrix as a reinforcing phase to significantly improve the mechanical properties. On this basis, the present invention uses a chemical grafting modification method to perform surface treatment on the fiber to obtain 4-ethyleneaniline modified carbon fiber, so that there is a chemical bond between the modified fiber and the matrix, the interface bonding degree is higher, the tensile strength of the printed product is further improved, and the anisotropy is further reduced. The present invention utilizes the bonding effect between the modified carbon fiber and the resin matrix to achieve isotropy while enhancing the mechanical properties of the material, and is expected to expand the practical application scenarios of photocurable 3D printed products in industry.

[0015] 2. The present invention provides a novel CF-enhanced photosensitive acrylic resin system that can be used for photocuring DLP 3D printing. 4-ethyleneaniline-modified carbon fiber can play a role in overlapping between layers, and is expected to make up for the weak interface bonding caused by the layer-by-layer manufacturing method. The method is simple to operate and has a significant effect on eliminating the anisotropy of photosensitive acrylic. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a schematic diagram of the reasons for the anisotropy of mechanical properties of light-curing 3D printed parts.

[0017] Figure 2 It is a schematic diagram of the principle of the present invention.

[0018] Figure 3 1 is a viscosity curve of the printing solution with different CF addition amounts provided in Experimental Example 1 of the present invention.

[0019] Figure 4 This is the relationship between the curing depth and the UV exposure energy provided in Experimental Example 1 of the present invention.

[0020] Figure 5 It is the 4-vinylaniline structure provided in Example 1 of the present invention.

[0021] Figure 6 This is a 3D printing process diagram of the modified CF reinforced sample provided in Example 1 of the present invention.

[0022] Figure 7 It is the XPS wide scan spectrum of CF before and after modification provided in Example 1 of the present invention.

[0023] Figure 8 It is the N1s peak of CF-Enamine provided in Example 1 of the present invention.

[0024] Fig. 9 It is the C1s peak of CF provided in Experimental Example 1 of the present invention.

[0025] Fig.10 It is the C1s peak of CF-Enamine provided in Example 1 of the present invention.

[0026] Fig.11 It is the anisotropy of the tensile properties of the modified CF composite material provided in Example 1 of the present invention.

[0027] Fig.12 It is the tensile fracture cross section of the modified CF reinforced sample printed in the horizontal direction provided in Example 1 of the present invention.

[0028] Fig.13 This is the tensile fracture cross-section of the modified CF reinforced sample printed in the vertical direction provided in Example 1 of the present invention.

[0029] Fig.14 This is the 3D printing lattice model provided by Example 1 of the present invention.

[0030] Fig.15 This is the 3D printed wrench model provided by Example 1 of the present invention. DETAILED DESCRIPTION

[0031] In the process of DLP 3D printing, each layer of photosensitive resin is cured and then the next layer is added, so the bonding force between the layers is limited. This lack of interlayer bonding makes the printed parts show extremely obvious anisotropy in mechanical properties, such as Figure 1 This anisotropy will lead to the aggravation of stress concentration when the part is subjected to complex stress, which will have an adverse effect on the overall performance of the part.

[0032] The current methods to solve the anisotropy of mechanical properties of photocurable 3D printed products mainly include toughening with core-shell particles, building dual-curing networks, and introducing dynamic covalent bonds. The strategies adopted in these works are to strengthen the bonding between layers. However, the addition of core-shell particles cannot eliminate the anisotropy of elongation at break; the photothermal dual-curing system requires additional heating treatment; the introduction of dynamic disulfide bonds requires the design and synthesis of special structures, and its tensile strength value is low.

[0033] Based on this situation, the present invention provides a new CF enhanced photosensitive acrylate resin system that can be used for photocuring DLP 3D printing. Figure 2 As shown, the present invention uses a chemical grafting modification method to perform surface treatment on the fiber to obtain 4-ethyleneaniline modified carbon fiber, so that a chemical bond exists between the modified fiber and the matrix, and the interface bonding degree is higher. The 4-ethyleneaniline modified carbon fiber can play an overlapping role between layers, and is expected to make up for the weak interface bonding force caused by the layer-by-layer stacking manufacturing method, thereby further improving the tensile strength of the printed product and further reducing the anisotropy.

[0034] The present invention has the following advantages:

[0035] On the one hand, the present invention utilizes the bonding effect between modified carbon fiber and resin matrix to achieve isotropy while enhancing the mechanical properties of the material, which is expected to expand the practical application scenarios of photocurable 3D printed products in industry.

[0036] On the other hand, the method is simple to operate and has a significant effect on eliminating the anisotropy of photosensitive acrylate.

[0037] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments. However, this should not be understood as limiting the scope of the present invention to the following examples. Various substitutions or changes made according to common technical knowledge and customary means in the art without departing from the above-mentioned method concept of the present invention should be included in the scope of the present invention.

[0038] Example

[0039] The first aspect of the present invention is to provide an isotropic photocurable material, which is a photosensitive resin in which 4-ethyleneaniline modified carbon fibers are distributed, wherein the content of the 4-ethyleneaniline modified carbon fibers is 1-3wt.% of the photosensitive resin, and the 4-ethyleneaniline modified carbon fibers are 4-ethyleneaniline grafted on the surface of the carbon fibers, wherein the tensile strength anisotropy of the isotropic photocurable material is less than 11.0%, and the elongation at break anisotropy is less than 8.5%.

[0040] Furthermore, the content of the 4-ethylene aniline modified carbon fiber is 2-3 wt.% of the photosensitive resin. Furthermore, the content of the 4-ethylene aniline modified carbon fiber is 3 wt.% of the photosensitive resin.

[0041] Furthermore, the tensile strength anisotropy of the isotropic light-curable material is less than 8.0%, and the elongation at break anisotropy is less than 6.0%. More preferably, the tensile strength anisotropy of the isotropic light-curable material is less than 4.0%, and the elongation at break anisotropy is less than 2.5%.

[0042] Furthermore, the tensile strength of the isotropic photocurable material is higher than 60 MPa.

[0043] Furthermore, the elongation at break of the isotropic light-curable material is higher than 5%.

[0044] Furthermore, the isotropic photocurable material has C1s peaks of C=C, CC, N=CO and O=CO at 284.7 eV, 285.8 eV, 287.0 eV and 289.2 eV, respectively.

[0045] The second aspect of the present invention is to provide the use of 4-ethyleneaniline modified carbon fiber in the preparation of isotropic photocurable material, wherein the isotropic photocurable material is the isotropic photocurable material as described above, and the 4-ethyleneaniline modified carbon fiber is carbon fiber with 4-ethyleneaniline grafted on the surface.

[0046] The third aspect of the present invention is to provide a method for preparing an isotropic photocurable material, the preparation method comprising the following steps:

[0047] (1) Using 4-vinylaniline as a raw material, a chemical grafting modification method is used to perform surface treatment on carbon fiber to obtain 4-vinylaniline modified carbon fiber;

[0048] (2) Epoxy acrylate, dicyclopentadiene acrylate and a photoinitiator are mixed to obtain a photosensitive resin, and 4-vinylaniline modified carbon fiber is added as a reinforcing phase, wherein the content of the 4-vinylaniline modified carbon fiber is 1-3wt.% of the photosensitive resin and the carbon fiber is evenly dispersed, and an isotropic photocurable material is obtained by photocuring 3D printing.

[0049] Furthermore, the content of the 4-ethylene aniline modified carbon fiber is 2-3 wt.% of the photosensitive resin. Furthermore, the content of the 4-ethylene aniline modified carbon fiber is 3 wt.% of the photosensitive resin.

[0050] Furthermore, in step (2), the monofunctional acrylate monomer includes one or more of isobornyl acrylate, dicyclopentadiene acrylate, hydroxyethyl acrylate, diethoxy acrylate, and tetrahydrofuran acrylate.

[0051] Further, in step (2), the photoinitiator includes one or more of 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and / or

[0052] Furthermore, in step (2), the mass ratio of the bisphenol A epoxy acrylate, the monofunctional acrylate monomer and the photoinitiator is 20-36:4-20:0.4-1.2.

[0053] Furthermore, the dispersion time is 1 to 5 minutes.

[0054] Furthermore, the light-curing 3D printing is followed by post-curing, and the time of the post-curing is 10 to 50 seconds.

[0055] Furthermore, the specific method of step (1) includes:

[0056] (i) adding an acidic oxidant to the carbon fiber CF to carry out an oxidation reaction, washing with water and drying to obtain an oxidized carbon fiber OCF;

[0057] (ii) adding OCF and a catalyst to one of ethanol, isopropanol and N,N-dimethylformamide solutions of 4-vinylaniline to carry out an amidation reaction under a nitrogen atmosphere;

[0058] (iii) After the reaction is completed, the carbon fiber is washed with N,N-dimethylformamide and dried to obtain 4-ethyleneaniline modified carbon fiber CF-Enamine.

[0059] Furthermore, in step (i), the acidic oxidant is one or more strong acids including concentrated sulfuric acid, nitric acid or hydrochloric acid.

[0060] Furthermore, in step (i), the amount of the acidic oxidant added is 50 to 200 ml based on 2 g equivalent of carbon fiber.

[0061] Furthermore, in step (i), the reaction temperature of the oxidation reaction is 50-100° C., and the reaction time is 2-10 h.

[0062] Furthermore, in step (i), the drying comprises vacuum drying at 50-120° C. for 6-12 hours.

[0063] Furthermore, in step (ii), the mass ratio of OCF to 4-vinylaniline is 0.5 to 3:1, preferably 0.6 to 2.4:1.

[0064] Furthermore, in step (ii), the catalyst for the amidation reaction includes one or more of dicyclohexylcarbodiimide, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide.

[0065] Furthermore, in step (ii), the molar ratio of the catalyst to 4-ethyleneaniline is 1:2.0-3.0.

[0066] Furthermore, in step (ii), the reaction temperature of the amidation reaction is 100-150° C., and the reaction time is 2-10 h.

[0067] Furthermore, in step (ii), the drying comprises vacuum drying at 50-120° C. for 6-12 hours.

[0068] The fourth aspect of the present invention is to provide the use of the isotropic photocurable material as described above or prepared by any of the methods described above in the field of medical equipment, electronic components, automotive parts or aerospace.

[0069] The present invention will be further described below in conjunction with the accompanying drawings and Examples. According to the following examples, the present invention can be better understood. However, it is easy for those skilled in the art to understand that the specific material ratios, process conditions and results described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0070] Experimental Example 1 Preparation of unmodified CF reinforced photocurable composite material

[0071] In order to explore the process conditions for the preparation of modified CF materials for photocurable composite materials, the present invention first uses CF as raw material and studies the influence of different CF addition amounts on the preparation of CF-enhanced photocurable composite materials, in order to, on the one hand, serve as a control for the use of modified CF materials in the preparation of modified CF-enhanced photocurable composite materials, and on the other hand, provide a certain reference for the process conditions for the use of modified CF materials in the preparation of modified CF-enhanced photocurable composite materials.

[0072] The specific preparation method of the CF reinforced light-cured composite material in this experimental example is as follows:

[0073] Bisphenol A epoxy acrylate (24 g), dicyclopentadiene acrylate (16 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.8 g) were mixed to obtain a photosensitive resin.

[0074] Then, different amounts of CF were added to the photosensitive resin (specifically 0, 0.4, 0.8, 1.2, 1.6, and 2.0 g, corresponding to 0 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%), and dispersed in a high-speed disperser at 3000 r / min for 3 min to obtain a uniformly mixed CF-enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405nm DLP 3D printer to prepare a CF composite material.

[0075] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0076] See attached Figure 3 , which is the viscosity curve of the printing solution with different CF addition amounts provided in Experimental Example 1 of the present invention. It can be seen from the figure that when the CF addition amount is 5wt% and the shear rate is 1s -1 When the viscosity of the resin system reaches 24.2Pa·s, it is difficult to print, while the viscosity of the printing solution with 0-4wt% is up to 5.5Pa·s, which can meet the requirements of DLP 3D printing. Therefore, based on the test results, the addition amount of 0-4wt% is used in other performance tests of CF-enhanced light-cured composite materials in the subsequent experimental examples.

[0077] See attached Figure 4 , which is the relationship between the curing depth and the ultraviolet exposure energy provided in Experimental Example 1 of the present invention. As can be seen from the figure, the transmission depth (Dp) and the critical ultraviolet exposure energy (Ec), that is, the minimum energy required to start curing, can be obtained by fitting the curing depth (Cd) of the printing solution and the logarithm of the ultraviolet exposure energy E according to the Jacob equation:

[0078]

[0079] The higher the CF content, the lower the curing depth Cd of the composite material.

[0080] See attached Figure 5 , which is the 4-vinylaniline structure provided in Example 1 of the present invention.

[0081] Referring to Table 1, which shows the transmission depth and critical UV exposure energy provided by Example 1 of the present invention, as the CF content increases, the Dp and Ec values ​​show a downward trend, which means that the formation of the solidified layer starts earlier.

[0082] Table 1 Transmission depth and critical UV exposure energy

[0083]

[0084] Refer to Table 2, which is the tensile properties of the initial CF composite material provided in Experimental Example 1 of the present invention. When the photosensitive resin contains 3wt% CF, it has the highest tensile strength (59.7MPa). Compared with the sample prepared from pure resin (containing 0wt% CF), it has increased by 30.8%. Moreover, the tensile strength does not increase with the increase of CF content in the resin. It reaches a peak at 3wt% and then decreases with the increase of CF content in the resin. The present invention aims to prepare an isotropic photocurable material with good mechanical properties. When 3wt% CF is added, the composite material has the highest tensile strength. Therefore, in the subsequent embodiments, in the preparation process of the modified CF reinforced photocurable composite material, the addition amount of CF is controlled in the range of 0-3wt%, and the influencing factors of anisotropy are explored on the basis of ensuring good mechanical properties.

[0085] Table 2 Tensile properties of initial CF composites

[0086]

[0087] Example 1 Preparation of modified CF reinforced light-cured composite material

[0088] The embodiment of the present invention takes the process conditions of the above-mentioned experimental example 1 as a reference, adopts modified CF as a raw material, and prepares a modified CF reinforced light-cured composite material.

[0089] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0090] 1) Preparation of 4-ethyleneaniline modified carbon fiber CF-Enamine-1

[0091] 2g of carbon fiber CF was placed in a flask, and 120ml of nitric acid solution was added. The mixed solution was stirred at 80°C for 4h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 80°C for 12h to obtain oxidized carbon fiber (OCF).

[0092] OCF (1.2 g) and catalyst 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (2.4 g, 6.3 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (1 g, 7.4 mmol) and reacted at 120°C under nitrogen atmosphere for 6 h.

[0093] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 80°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (denoted as CF-Enamine-1).

[0094] 2) Preparation of CF-Enamine-1 enhanced light-cured composites

[0095] Bisphenol A epoxy acrylate (24 g), dicyclopentadiene acrylate (16 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.8 g) were mixed to obtain a photosensitive resin.

[0096] Then, 1.2 g of CF-Enamine-1 was added to the photosensitive resin, and the corresponding amount of CF-Enamine-1 was 3 wt.%. The mixture was dispersed in a high-speed disperser at 3000 r / min for 3 min to obtain a uniformly mixed CF-Enamine-1 enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-1 enhanced photocurable composite material.

[0097] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0098] See attached Figure 5 , which is the 4-vinylaniline structure provided in Example 1 of the present invention.

[0099] See attached Figure 6 , which is a 3D printing process diagram of the modified CF reinforced sample provided in Example 1 of the present invention, using 4-vinylaniline modified CF as the reinforcement, epoxy acrylate and dicyclopentadiene acrylate as the matrix, and using DLP 3D printing to prepare the modified CF reinforced composite material.

[0100] See attached Figure 7 It is the XPS wide scan spectrum of CF before and after modification provided in Experimental Example 1 and Example 1 of the present invention. The signal peaks of C, N and O of CF-Enamine-1 are located near 284.8, 400.1 and 532.9 eV, respectively. Compared with CF, the N element content on the surface of CF-Enamine-1 fiber is significantly increased.

[0101] See attached Figure 8 , which is the N1s peak of CF-Enamine-1 provided in Example 1 of the present invention, has only a single peak at 400.2 eV, corresponding to N=CO.

[0102] See attached Fig. 9 , which is the C1s peak of CF provided in Experimental Example 1 of the present invention. The C1s spectrum of the untreated CF can be divided into four peaks: 284.7 eV, 285.7 eV, 286.6 eV and 289.1 eV, corresponding to C=C, CC, CO and O=CO, respectively, indicating that fiber fragments or contaminants may be attached to the surface of CF during cutting and storage, making the fiber surface not completely inert, but having some functional groups.

[0103] See attached Fig.10 , which is the C1s peak of CF-Enamine-1 provided in Example 1 of the present invention. The C1s peak of CF-Enamine-1 can be divided into the following four peaks: C=C, CC, N=CO and O=CO, which are located at 284.7eV, 285.8eV, 287.0eV and 289.2eV respectively. Figure 5 The appearance of N=CO is due to the condensation reaction between the carboxyl group on CF and the amino group on 4-vinylaniline under the action of 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate.

[0104] Refer to Table 3, which shows the tensile properties in different directions of the modified CF composite material provided in Example 1 of the present invention. When 3wt% CF-Enamine-1 is added, the tensile strength of the printed sample reaches 66.0MPa, which is 44.7% higher than that of the resin sample and 10.6% higher than that of the CF reinforced composite material of Experimental Example 1.

[0105] Table 3 Tensile properties of modified CF-Enamine composites in different directions

[0106]

[0107] See attached Fig.11 , which is the tensile property anisotropy of the modified CF composite material provided in Example 1 of the present invention, is calculated according to the following formula to obtain the anisotropy of the printed material:

[0108]

[0109] Compared with the pure resin printed sample (40.6%), the tensile strength anisotropy of the printed sample containing 3wt% CF in Experimental Example 1 was greatly reduced to 12.1%, and the anisotropy of the elongation at break was reduced to 8.9%. After the fiber was modified in Example 1, the tensile strength anisotropy of the reinforced printed sample containing 3wt% modified CF was further reduced to 3.3%, and the anisotropy of the elongation at break was reduced to 1.9%.

[0110] See attached Fig.12 , 13 They are respectively the tensile fracture sections of the modified CF reinforced sample printed in the horizontal direction and the tensile fracture sections of the modified CF reinforced sample printed in the vertical direction provided in Example 1 of the present invention. CF-Enamine-1 is randomly distributed in the resin as a whole, and some fibers will penetrate different layers, that is, connecting layers together like nails, thereby improving the interlayer adhesion and thus improving the mechanical strength in this direction.

[0111] See attached Fig.14 , which is the 3D printing lattice model provided in Example 1 of the present invention.

[0112] See attached Fig.15 , which is the 3D printed wrench model provided in Example 1 of the present invention.

[0113] Example 2 Preparation of modified CF reinforced light-cured composite material

[0114] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0115] 1) Preparation of 4-ethyleneaniline modified carbon fiber CF-Enamine-2

[0116] 2 g of carbon fiber was placed in a flask, and 120 ml of hydrochloric acid solution was added. The mixed solution was stirred at 90° C. for 8 h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 100° C. for 12 h to obtain oxidized carbon fiber (OCF).

[0117] OCF (2 g) and catalyst 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (1.21 g, 6.3 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (3 g, 22.2 mmol) and reacted at 100° C. under nitrogen atmosphere for 8 h.

[0118] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 100°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (denoted as CF-Enamine-2).

[0119] 2) Preparation of CF-Enamine-2 reinforced light-cured composites

[0120] Bisphenol A epoxy acrylate (20 g), hydroxyethyl acrylate (20 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.4 g) were mixed to obtain a photosensitive resin.

[0121] Then, 0.4 g of CF-Enamine-2 was added to the photosensitive resin (corresponding to an addition amount of CF-Enamine-2 of 1 wt.%), and dispersed for 3 min at 3000 r / min in a high-speed disperser to obtain a uniformly mixed CF-Enamine-2 enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-2 enhanced photocurable composite material.

[0122] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0123] The GF-Enamine-2 reinforced photocurable composite material sample prepared in this example has a tensile strength anisotropy of 10.7% and a breaking elongation anisotropy of 8.1%.

[0124] Example 3 Preparation of modified CF reinforced light-cured composite material

[0125] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0126] 1) Preparation of 4-ethyleneaniline modified carbon fiber CF-Enamine-3

[0127] 2g of carbon fiber was placed in a flask, and 60ml of nitric acid solution was added. The mixed solution was stirred at 80°C for 10h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 50°C for 12h to obtain oxidized carbon fiber (OCF).

[0128] OCF (2 g) and catalyst 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (2.4 g, 6.3 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (2 g, 14.8 mmol) and reacted at 100°C under nitrogen atmosphere for 10 h.

[0129] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 50°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (CF-Enamine-3).

[0130] 2) Preparation of CF-Enamine-3 reinforced photocurable composites

[0131] Bisphenol A epoxy acrylate (32 g), bisethoxy acrylate (8 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.8 g) were mixed to obtain a photosensitive resin.

[0132] Then, 0.8 g of CF-Enamine-3 was added to the photosensitive resin (corresponding to an addition amount of 2 wt.%), and dispersed for 3 min at 3000 r / min in a high-speed disperser to obtain a uniformly mixed CF-Enamine-3 enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-3 enhanced photocurable composite material.

[0133] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 50 seconds.

[0134] The GF-Enamine-3 reinforced photocurable composite material sample prepared in this example has a tensile strength anisotropy of 7.3% and a breaking elongation anisotropy of 4.9%.

[0135] Example 4 Preparation of modified CF reinforced light-cured composite material

[0136] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0137] 1) Preparation of 4-ethyleneaniline modified CF carbon fiber CF-Enamine-4

[0138] 2g of initial carbon fiber was placed in a flask, and 60ml of hydrochloric acid solution was added. The mixed solution was stirred at 100°C for 2h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 60°C for 12h to obtain oxidized carbon fiber (OCF).

[0139] OCF (1.2 g) and catalyst 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (2.4 g, 6.3 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (1 g, 7.4 mmol) and reacted at 140°C under nitrogen atmosphere for 10 h.

[0140] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 60°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (denoted as CF-Enamine-4).

[0141] 2) Preparation of CF-Enamine-4 reinforced light-cured composites

[0142] Bisphenol A epoxy acrylate (36 g), tetrahydrofuran acrylate (4 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.4 g) were mixed to obtain a photosensitive resin.

[0143] Then, 0.8 g of CF-Enamine-4 was added to the photosensitive resin (corresponding to an addition amount of CF-Enamine-4 of 2 wt.%), and dispersed in a high-speed disperser at 3000 r / min for 3 min to obtain a uniformly mixed CF-Enamine-4 enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-4 enhanced photocurable composite material.

[0144] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0145] The GF-Enamine-4 reinforced photocurable composite material sample prepared in this example has a tensile strength anisotropy of 6.6% and a breaking elongation anisotropy of 4.4%.

[0146] Example 5 Preparation of modified CF reinforced light-cured composite material

[0147] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0148] 1) Preparation of 4-ethyleneaniline modified carbon fiber CF-Enamine-5

[0149] 2g of initial carbon fiber was placed in a flask, and 180ml of sulfuric acid solution was added. The mixed solution was stirred at 60°C for 8h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 70°C for 12h to obtain oxidized carbon fiber (OCF).

[0150] OCF (1.2 g) and catalyst 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (2.4 g, 6.3 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (0.5 g, 3.7 mmol) and reacted at 120°C under nitrogen atmosphere for 8 h.

[0151] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 70°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (denoted as CF-Enamine-5).

[0152] 2) Preparation of CF-Enamine-5 reinforced light-cured composites

[0153] Bisphenol A epoxy acrylate (24 g), dicyclopentadiene acrylate (16 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.4 g) were mixed to obtain a photosensitive resin.

[0154] Then, 0.4 g of CF-Enamine-5 was added to the photosensitive resin (corresponding to an addition amount of CF-Enamine-5 of 1 wt.%), and dispersed in a high-speed disperser at 3000 r / min for 3 min to obtain a uniformly mixed CF-Enamine-5 enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-5 enhanced photocurable composite material.

[0155] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0156] The GF-Enamine-5 reinforced photocurable composite material sample prepared in this example has a tensile strength anisotropy of 10.4% and a breaking elongation anisotropy of 8.1%.

[0157] Example 6 Preparation of modified CF reinforced light-cured composite material

[0158] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0159] 1) Preparation of 4-ethyleneaniline modified carbon fiber CF-Enamine-6

[0160] 2g of initial carbon fiber was placed in a flask, and 120ml of nitric acid solution was added. The mixed solution was stirred at 80°C for 10h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 120°C for 12h to obtain oxidized carbon fiber (OCF).

[0161] OCF (1.2 g) and catalyst 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (1.2 g, 3.15 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (2 g, 14.8 mmol) and reacted at 100°C under nitrogen atmosphere for 4 h.

[0162] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 120°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (denoted as CF-Enamine-6).

[0163] 2) Preparation of CF-Enamine-6 ​​reinforced light-cured composites

[0164] Bisphenol A epoxy acrylate (28 g), isobornyl acrylate (12 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (0.8 g) were mixed to obtain a photosensitive resin.

[0165] Then, 0.8 g of CF-Enamine-6 ​​was added to the photosensitive resin, corresponding to an addition amount of CF-Enamine-6 ​​of 2 wt.%, and dispersed in a high-speed disperser at 3000 r / min for 3 min to obtain a uniformly mixed CF-Enamine-6 ​​enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-6 ​​enhanced photocurable composite material.

[0166] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0167] The GF-Enamine-6 ​​reinforced photocurable composite material sample prepared in this example has a tensile strength anisotropy of 7.6% and a breaking elongation anisotropy of 5.4%.

[0168] Example 7 Preparation of modified CF reinforced light-cured composite material

[0169] The specific preparation method of the modified CF reinforced light-cured composite material in this embodiment is as follows:

[0170] 1) Preparation of 4-ethyleneaniline modified carbon fiber CF-Enamine-7

[0171] 2g of carbon fiber CF was placed in a flask, and 120ml of hydrochloric acid solution was added. The mixed solution was stirred at 90°C for 5h, and after the reaction, the fiber was washed with deionized water and then dried in an oven at 60°C for 12h to obtain oxidized carbon fiber OCF.

[0172] OCF (1.2 g) and catalyst 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (0.60 g, 3.15 mmol) were added to 60 ml of N,N-dimethylformamide solution containing 4-vinylaniline (2 g, 14.8 mmol) and reacted at 150° C. under nitrogen atmosphere for 2 h.

[0173] The fiber was then washed with N,N-dimethylformamide and dried in a vacuum oven at 60°C for 12 h to obtain 4-ethyleneaniline modified carbon fiber (denoted as CF-Enamine-7).

[0174] 2) Preparation of CF-Enamine-7 reinforced light-cured composites

[0175] Bisphenol A epoxy acrylate (32 g), hydroxyethyl acrylate (8 g) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (1.2 g) were mixed to obtain a photosensitive resin.

[0176] Then, 0.8 g of CF-Enamine-7 was added to the photosensitive resin (corresponding to an addition amount of CF-Enamine-7 of 2 wt.%), and dispersed in a high-speed disperser at 3000 r / min for 3 min to obtain a uniformly mixed CF-Enamine-7 enhanced photosensitive resin solution. After removing the bubbles, the solution was poured into a commercial 405 nm DLP 3D printer to prepare a CF-Enamine-7 enhanced photocurable composite material.

[0177] After printing, ethanol was used to clean the remaining resin solution on the surface of the sample, and then a full-band crawler light curing machine was used for post-curing. The total curing time was about 30 seconds.

[0178] The GF-Enamine-7 reinforced photocurable composite material sample prepared in this example has a tensile strength anisotropy of 7.1% and a breaking elongation anisotropy of 5.5%.

[0179] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An isotropic light-curable material, characterized in that: The isotropic photocurable material is a photosensitive resin in which 4-ethyleneaniline modified carbon fibers are distributed, wherein the content of the 4-ethyleneaniline modified carbon fibers is 1-3wt.% of the photosensitive resin, and the 4-ethyleneaniline modified carbon fibers are 4-ethyleneaniline grafted on the surface of the carbon fibers, wherein the tensile strength anisotropy of the isotropic photocurable material is less than 11.0%, and the elongation at break anisotropy is less than 8.5%.

2. The isotropic light-curable material according to claim 1, characterized in that: The content of the 4-ethyleneaniline modified carbon fiber is 2-3wt.% of the photosensitive resin; and / or Preferably, the tensile strength anisotropy of the isotropic light-curing material is less than 8.0%, and the elongation at break anisotropy is less than 6.0%; further preferably, the tensile strength anisotropy of the isotropic light-curing material is less than 4.0%, and the elongation at break anisotropy is less than 2.5%; and / or Preferably, the tensile strength of the isotropic light-curable material is higher than 60 MPa; and / or Preferably, the elongation at break of the isotropic light-curable material is higher than 5%; and / or Preferably, the isotropic photocurable material has C1s peaks of C=C, CC, N=CO and O=CO at 284.7 eV, 285.8 eV, 287.0 eV and 289.2 eV, respectively. 3.4-Use of ethylene aniline modified carbon fiber in the preparation of isotropic photocurable materials, characterized in that: The isotropic light-curing material is the isotropic light-curing material according to claim 1 or 2, and the 4-vinylaniline-modified carbon fiber is a carbon fiber having 4-vinylaniline grafted on its surface.

4. A method for preparing an isotropic photocurable material, characterized in that: Described preparation method comprises the following steps: (1) Using 4-vinylaniline as a raw material, a chemical grafting modification method is used to perform surface treatment on carbon fiber to obtain 4-vinylaniline modified carbon fiber; (2) Epoxy acrylate, dicyclopentadiene acrylate and a photoinitiator are mixed to obtain a photosensitive resin, and 4-vinylaniline modified carbon fiber is added as a reinforcing phase, wherein the content of the 4-vinylaniline modified carbon fiber is 1-3wt.% of the photosensitive resin and the carbon fiber is evenly dispersed, and an isotropic photocurable material is obtained by photocuring 3D printing.

5. The preparation method according to claim 4, characterized in that: In step (2), the monofunctional acrylate monomer includes one or more of isobornyl acrylate, dicyclopentadiene acrylate, hydroxyethyl acrylate, diethoxy acrylate, tetrahydrofuran acrylate; and / or Preferably, in step (2), the photoinitiator comprises one or more of 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and / or Preferably, in step (2), the mass ratio of bisphenol A epoxy acrylate, monofunctional acrylate monomer and photoinitiator is 20-36:4-20:0.4-1.

2.

6. The preparation method according to claim 4, characterized in that: The content of the 4-ethyleneaniline modified carbon fiber is 2-3wt.% of the photosensitive resin; and / or The dispersion time is 1 to 5 minutes; and / or Preferably, the light-curing 3D printing is followed by post-curing, and the time of the post-curing is 10 to 50 seconds.

7. The preparation method according to claim 4, characterized in that: The specific method of step (1) includes: (i) adding an acidic oxidant to the carbon fiber CF to carry out an oxidation reaction, washing with water and drying to obtain an oxidized carbon fiber OCF; (ii) adding OCF and a catalyst to one of ethanol, isopropanol and N,N-dimethylformamide solutions of 4-vinylaniline to carry out an amidation reaction under a nitrogen atmosphere; (iii) After the reaction is completed, the carbon fiber is washed with N,N-dimethylformamide and dried to obtain 4-ethyleneaniline modified carbon fiber CF-Enamine.

8. The preparation method according to claim 7, characterized in that: In step (i), the acidic oxidant is one or more strong acids including concentrated sulfuric acid, nitric acid or hydrochloric acid; and / or Preferably, in step (i), the amount of the acidic oxidant added is 50 to 200 ml based on 2 g equivalent of carbon fiber; and / or Preferably, in step (i), the reaction temperature of the oxidation reaction is 50-100° C., and the reaction time is 2-10 h; and / or Preferably, in step (i), the drying comprises vacuum drying at 50-120° C. for 6-12 hours.

9. The preparation method according to claim 7, characterized in that: In step (ii), the mass ratio of OCF to 4-vinylaniline is 0.5 to 3:1; preferably 0.6 to 2.4:1; and / or Preferably, in step (ii), the catalyst for the amidation reaction comprises one or more of dicyclohexylcarbodiimide, 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; and / or Preferably, in step (ii), the molar ratio of the catalyst to 4-vinylaniline is 1:2.0-3.0; and / or Preferably, in step (ii), the reaction temperature of the amidation reaction is 100-150° C., and the reaction time is 2-10 h; and / or Preferably, in step (ii), the drying comprises vacuum drying at 50-120° C. for 6-12 hours.

10. Use of the isotropic photocurable material according to claim 1 or 2, or prepared by the method according to any one of claims 4 to 9 in the fields of medical equipment, electronic components, automotive parts or aerospace.

Images