An efficient manufacturing method for composite materials based on front-end polymerization initiation point design

Abstract

The present invention provides a highly efficient method for manufacturing composite materials based on front-end polymerization initiation point design. The method relates to the manufacture of forming materials containing polymeric substances and belongs to the technical field of general processes for processing and dispensing polymeric materials. The present invention rapidly and energy-efficiently prepares epoxy resin composite materials with excellent mechanical properties by configuring an epoxy resin front-end polymerization solution and initiating front-end polymerization at multiple points. The present invention has the advantages of high designability and ease of operation. By initiating front-end polymerization at multiple points, the method achieves rapid and energy-efficient manufacturing of epoxy resins and their composite materials while maintaining mechanical properties. The method has broad application prospects in the mass production of epoxy resins and composite materials and the manufacture of large-scale structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of general process of processing and proportioning of polymer materials, relates to the manufacture of forming materials containing polymer substances, and specifically relates to a high-efficiency manufacturing method of composite materials based on front-end polymerization initiation point design. Background Art

[0002] Epoxy resin is the most commonly used matrix material in composite materials and is widely used in various fields such as aviation industry, marine, automobile and sporting goods. Epoxy resin-based composite materials usually require the addition of amines or anhydrides as curing agents and are formed by high-temperature curing for several hours or even days. Traditional thermoforming methods consume a lot of energy, have high emissions of waste gases such as carbon dioxide, require large curing equipment, and cannot be cured in situ. Therefore, in order to achieve high efficiency, energy saving and rapid batch curing of epoxy resins and their composites, it is urgent to find a new molding method. Front-end polymerization (FP) is a method that relies on the exothermic nature of the polymerization reaction. After light or heat stimulation, a local reaction zone is formed. This reaction zone will initiate further reactions in the adjacent areas, and the curing molding of epoxy resins and their composites can be completed within minutes.

[0003] When it comes to manufacturing, especially for large-scale production and the production of large components such as wind turbine blades, improving the efficiency of the curing process is key to reducing production costs. Existing research has improved curing efficiency by increasing the initiator concentration and the initial temperature of the resin. Chinese patent CN108431075B prepares epoxy resin through front-end polymerization. This technology promotes the propagation of the reaction front by increasing the initiator concentration. However, high initiator concentration may cause pores to form during the front-end polymerization process, resulting in a significant decrease in product quality. In addition, Goli et al. disclosed in Compos. Part B-Eng. 199, 108306 (2020) a front-end polymerization based on dicyclopentadiene resin and found that as the initial temperature of the resin increased, the front-end speed increased. However, high front-end temperature can easily lead to bulk polymerization of the resin. Therefore, simply increasing the initiator concentration and the initial temperature of the resin to increase the curing efficiency has certain limitations. Summary of the Invention

[0004] The present invention is made to solve the above problems and aims to provide a method for efficiently manufacturing composite materials based on the design of front-end polymerization initiation points.

[0005] The present invention provides a high-efficiency manufacturing method for a composite material based on a front-end polymerization initiation point design, which has the following characteristics and comprises the following steps: S10, preparing a first mixed solution of an epoxy resin, a diluent, a photoinitiator and a thermal initiator, wherein the molar percentage concentration of the photoinitiator in the first mixed solution is 0.5 mol%-5.5 mol%, the molar percentage concentration of the thermal initiator in the first mixed solution is 0.5 mol%-5.5 mol%, the molar ratio of the diluent to the epoxy resin is (2-3):(7-8), the photoinitiator is 4-(octyloxyphenyl)phenyliodine hexafluoroantimonate and / or tetraalkyl (perfluorotert-butyloxy)aluminate anion, the thermal initiator is benzopinacol, and the epoxy resin is bisphenol A diglycidyl ester; A20, adding a discrete filler to the first mixed solution and mixing uniformly to obtain a second mixed solution, wherein the discrete filler is a reinforcing and functional filler, and the mass fraction of the discrete filler in the second mixed solution is 0.5 wt%-35 wt%; A30, heating the second mixed solution to a preset initial temperature of 30°C-70°C. ℃ to obtain a first epoxy resin front-end polymerization solution; A40, after pouring the first epoxy resin front-end polymerization solution into the mold, according to the actual production requirements for curing time and energy consumption, the number and position arrangement of the initiation points are designed based on the propagation speed of the polymerization front end; A50, by ultraviolet light irradiation or local heating, the front-end polymerization is initiated at the position of the initiation point. After the front end is initiated, the ultraviolet light or the heating point is removed, and the polymerization front propagates by self-propagation due to the exothermic heat of the polymerization reaction. The first epoxy resin front-end polymerization solution is rapidly cured from the initiation point at a propagation rate of not less than 2.5 cm / min and the curing degree is greater than 95%, and finally a fully cured epoxy resin is obtained.

[0006] The present invention provides a high-efficiency manufacturing method for a composite material based on a front-end polymerization initiation point design, which has the following characteristics and comprises the following steps: S10, preparing a first mixed liquid of an epoxy resin, a diluent, a photoinitiator and a thermal initiator, wherein the molar percentage concentration of the photoinitiator in the first mixed liquid is 0.5 mol% to 5.5 mol%, the molar percentage concentration of the thermal initiator in the first mixed liquid is 0.5 mol% to 5.5 mol%, the molar ratio of the diluent to the epoxy resin is (2-3):(7-8), the photoinitiator is 4-(octyloxyphenyl)phenyliodine hexafluoroantimonate and / or tetraalkyl (perfluorotert-butyloxy)aluminate anion, the thermal initiator is benzopinacol, and the epoxy resin is bisphenol A diglycidyl ester; B20, heating the first mixed liquid to a preset initial temperature of 30°C to 70°C ℃ to obtain a second epoxy resin front-end polymerization solution; B30, laying a continuous fiber filler in a mold, wherein the continuous fiber filler is a continuous fiber fabric, and the mass ratio of the continuous fiber filler to the second epoxy resin front-end polymerization solution is 5:95~35:65; B40, after the second epoxy resin front-end polymerization solution is poured into the mold, the number and position arrangement of the initiation points are designed based on the propagation speed of the polymerization front according to the actual production requirements for curing time and energy consumption; B50, the front-end polymerization is initiated at the position of the initiation point by ultraviolet light irradiation or local heating. After the front-end is initiated, the ultraviolet light or the heating point is removed, and the polymerization front propagates by self-propagation due to the exothermic heat of the polymerization reaction. The second epoxy resin front-end polymerization solution is rapidly cured from the initiation point at a propagation rate of not less than 2.7 cm / min and the curing degree is greater than 95%, thereby finally obtaining a fully cured epoxy resin-based composite material.

[0007] In the efficient manufacturing method of composite materials based on the front-end polymerization initiation point design provided by the present invention, it can also have the following characteristics: wherein, step S10 includes the following sub-steps: S11, adding the photoinitiator and the thermal initiator into the organic solvent and stirring at high speed until dissolved to obtain an initiator solution; S12, adding the epoxy resin and the diluent into the initiator solution, mixing them evenly, and then discharging the organic solvent to obtain a first mixed liquid.

[0008] The method for efficiently manufacturing a composite material based on the front-end polymerization initiation point design provided by the present invention may also have the following characteristics: wherein, in step S11, the organic solvent includes dichloromethane and / or ethyl acetate.

[0009] In the efficient manufacturing method of composite materials based on the front-end polymerization initiation point design provided by the present invention, it can also have the following characteristics: wherein, in step S10, the diluent includes any one or more of 3-ethyl-3-oxetane methanol, glycidyl ester neopentyl glycol diglycidyl ester, hexanediol diglycidyl ester, cyclohexanedimethanol and cyclohexyl epoxy ester.

[0010] The method for efficiently manufacturing a composite material based on the front-end polymerization initiation point design provided by the present invention may also have the following characteristics: wherein, in step S10, the molar ratio of the photoinitiator to the thermal initiator is 1:0.5 to 1:2.

[0011] The efficient manufacturing method of composite materials based on the front-end polymerization initiation point design provided by the present invention may also have the following characteristics: wherein, in step A30 or step B20, the heating operation is achieved by an oven, a heating pad or a heating table.

[0012] The efficient manufacturing method of composite materials based on the front-end polymerization initiation point design provided by the present invention may also have the following characteristics: wherein, in step A30 or step B40, the first epoxy resin front-end polymerization solution or the second epoxy resin front-end polymerization solution is also subjected to vacuum degassing treatment.

[0013] In the efficient manufacturing method of composite materials based on the front-end polymerization initiation point design provided by the present invention, it can also have the following characteristics: wherein, in step A40 or step B40, the number of initiation points is the ratio of the total energy consumption to the energy consumption of a single initiation point. When the actual production requires the lowest energy consumption and curing time, the curing area of ​​the first epoxy resin front-end polymerization solution or the second epoxy resin front-end polymerization solution in the mold is approximated to a rectangular area of ​​length multiplied by width, all polymerization fronts start from the initiation point, and the area to be cured is divided into squares with equal sides along the length and width, and the polymerization front is initiated at the center of the square at the same time.

[0014] The efficient manufacturing method of composite materials based on the front-end polymerization initiation point design provided by the present invention may also have the following characteristics: wherein, in step A50 or step B50, when the method of initiating front-end polymerization is ultraviolet light irradiation, the wavelength of the ultraviolet light source is 365nm, and the irradiation time is 15 s to 20 s; when the method of initiating front-end polymerization is local heating, the local heating is implemented by electric soldering iron heating or laser heating.

[0015] The present invention provides a highly efficient method for manufacturing composite materials based on a front-end polymerization initiation point design, which has the following beneficial effects:

[0016] (1) The resin formula design of the mixed liquid in step S10 of the present invention can effectively avoid solidified gas products and resin pyrolysis during the front-end polymerization process, avoid the formation of pores in the merged area, and maintain the mechanical properties of the material.

[0017] (2) The ultraviolet light irradiation initiation method selected in steps A40 to A50 or steps B40 to B50 of the present invention can adjust the irradiation position as needed according to the product structure, thereby facilitating the increase or decrease of the number of initiation points and the arrangement design.

[0018] (3) The multi-point initiated front-end polymerization molding method selected in steps A40 to A50 or steps B40 to B50 of the present invention can shorten the molding cycle of several hours or even longer to a few minutes, while avoiding long-term high-temperature treatment and reducing energy consumption by about 8 orders of magnitude.

[0019] (3) The present invention utilizes self-propagating front-end polymerization, which relies on the exothermic heat of the polymerization reaction. Once the polymerization front is initiated, no further energy input is required. By designing the number and location of initiation points, multiple polymerization fronts can diffuse simultaneously, enabling rapid and energy-saving molding and manufacturing of epoxy resins and their composite materials.

[0020] (4) The front-end polymerization selected in the present invention has high heat release and rapid heat release, which can achieve complete curing. At the same time, the high front-end merging temperature enhances the cross-linking density of the epoxy resin, thereby significantly improving the mechanical properties of the sample.

[0021] (5) The high-efficiency manufacturing method of composite materials based on the front-end polymerization initiation point design of the present invention is simple to operate and flexible in design. The number and arrangement of initiation points can be selected as needed, and both curing efficiency and mechanical properties can be taken into account. It is a fast, efficient and energy-saving method for manufacturing high-performance epoxy resins and their composite materials. It has broad application prospects in the mass production of epoxy resins and composite materials and the manufacture of large structural parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flowchart of a method for efficiently manufacturing a composite material based on a front-end polymerization initiation point design according to Example 1 of the present invention.

[0023] Figure 2 Schematic diagram of the triggering point arrangement design of Example 1 of the present invention.

[0024] Figure 3 Schematic diagram of the triggering point arrangement design of Example 2 of the present invention.

[0025] Figure 4 This is a flowchart of a method for efficiently manufacturing a composite material based on a front-end polymerization initiation point design according to Example 3 of the present invention.

[0026] Figure 5 Schematic diagram of the triggering point arrangement design of Example 3 of the present invention.

[0027] Figure 6 is a SEM image of comparative sample 1 of the test example of the present invention.

[0028] Figure 7 3 is a comparison of the bending properties of the comparative samples 1 and 2 of the test examples of the present invention.

[0029] Figure 83 is a comparison of the bending properties of the test example sample 3 of the present invention and the comparative sample 3. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the following embodiments and accompanying drawings specifically illustrate a method for efficiently manufacturing a composite material based on a front-end polymerization initiation point design of the present invention.

[0031] Example 1

[0032] Figure 1 This is a flowchart of a method for efficiently manufacturing a composite material based on a front-end polymerization initiation point design according to Example 1 of the present invention.

[0033] like Figure 1 As shown, this embodiment provides a method for efficiently manufacturing composite materials based on front-end polymerization initiation point design, comprising the following steps:

[0034] S10, preparing a first mixed solution of epoxy resin, diluent, photoinitiator and thermal initiator, including the following sub-steps S11-S12:

[0035] S11, adding a photoinitiator and a thermal initiator into an organic solvent and stirring at high speed until dissolved to obtain an initiator solution.

[0036] The photoinitiator is 4-(octyloxyphenyl)phenyliodine hexafluoroantimonate (I-Sb) and / or tetraalkyl (perfluorotert-butyloxy)aluminate anion (I-Al). Specifically, in this embodiment, the photoinitiator is I-Sb.

[0037] The thermal initiator was benzopinacol (TPED).

[0038] The organic solvent includes dichloromethane and / or ethyl acetate. Specifically in this embodiment, the organic solvent is dichloromethane.

[0039] S12, adding epoxy resin and diluent into the initiator solution and mixing evenly, then draining the organic solvent to obtain a first mixed solution.

[0040] The epoxy resin is bisphenol A diglycidyl ester (BADGE).

[0041] The diluent includes any one or more of 3-ethyl-3-oxetanol (EOM), glycidyl ester neopentyl glycol diglycidyl ester (NPDGE), hexanediol diglycidyl ester (HDDGE), cyclohexanedimethanol (CHDGE), and cyclohexyl epoxy ester (CE). Specifically, in this embodiment, the diluent is EOM.

[0042] In the above steps S11 to S12, the molar percentage concentrations of the photoinitiator I-Sb and the thermal initiator TPED in the finally prepared first mixed solution of I-Sb / TPED / EOM / BADGE are controlled to be 0.5 mol%~5.5 mol%, the feeding molar ratio of the photoinitiator I-Sb to the thermal initiator TPED is 1:0.5~1:2, and the molar ratio of the diluent EOM to the epoxy resin BADGE is controlled to be (2~3):(7~8).

[0043] Specifically in this embodiment, the parameters are selected as follows: the molar ratio of the photoinitiator I-Sb and the thermal initiator TPED is controlled to be 1:1, the molar percentage concentrations of the photoinitiator I-Sb and the thermal initiator TPED in the first mixed solution of I-Sb / TPED / EOM / BADGE finally prepared are both controlled to be 1 mol%, and the molar ratio of the diluent EOM to the epoxy resin BADGE is controlled to be 2:8.

[0044] A20, adding the discrete filler to the first mixed solution and mixing uniformly to obtain a second mixed solution.

[0045] The discrete filler is a reinforcing and functional filler, and includes any one or more of chopped glass fibers, carbon nanotubes, graphite, and conductive metal fillers. After the discrete filler is added to the mixed solution, the mass fraction of the discrete filler in the system is 0.5 wt% to 35 wt%.

[0046] Specifically, in this embodiment, the discrete filler is carbon nanotubes. After the discrete filler is added to the mixed solution, the molar concentration of the discrete filler is 3 mol%.

[0047] The discrete fillers were added to the mixed solution and mixed uniformly by magnetic stirring at 50 °C for 10 min to uniformly disperse the entire system.

[0048] A30, heating the second mixed solution to a preset initial temperature of 30° C. to 70° C. to obtain a first epoxy resin front-end polymerization solution.

[0049] The heating operation is achieved by an oven, a heating pad or a heating table.

[0050] Specifically in this embodiment, the preset initial temperature is selected to be 50° C., and the heating operation is achieved by a vacuum oven, which can perform a degassing treatment on the first epoxy resin front-end polymerization solution while heating and keeping the temperature.

[0051] A40, after the first epoxy resin front-end polymerization solution is poured into the mold, the number and position arrangement of the initiation points are designed based on the propagation speed of the polymerization front end according to the actual production requirements for curing time and energy consumption.

[0052] Among them, the number of initiation points is the ratio of the total energy consumption to the energy consumption of a single initiation point. When actual production requires the lowest energy consumption and curing time, the curing area of ​​the first epoxy resin front-end polymerization solution in the mold is approximated to a rectangular area of ​​length multiplied by width. All polymerization fronts start from the initiation point, and the area to be cured is divided into squares with equal side lengths along the length and width respectively, and the polymerization front is initiated at the center of the square at the same time.

[0053] Specifically in this embodiment, the energy consumption must be less than 2500 J and the curing time must be less than 15 s. The power of each initiation point is 45 W, so the number of initiation points is set to 3. Figure 2 This is a schematic diagram of the trigger point arrangement design of Example 1 of the present invention. The trigger point arrangement design in this step is as follows Figure 2 As shown, there are three triggering points in total. The three triggering points are arranged in a line-connected isosceles triangle shape.

[0054] A50, initiates front-end polymerization, exothermic self-propagation and solidification.

[0055] The front-end polymerization is initiated at the initiation point by ultraviolet light irradiation or local heating. After the front-end is initiated, the ultraviolet light or heating point is removed, and the polymerization front propagates by itself due to the exothermic heat of the polymerization reaction. The first epoxy resin front-end polymerization solution rapidly solidifies from the initiation point at a propagation rate of not less than 2.5 cm / min and a degree of cure greater than 95%, ultimately obtaining a fully cured epoxy resin. When the front-end polymerization is initiated by ultraviolet light irradiation, the wavelength of the ultraviolet light source is 365 nm, and the irradiation time is 15 s to 20 s. When the front-end polymerization is initiated by local heating, the local heating can be achieved by heating with a soldering iron or laser.

[0056] Specifically, in this embodiment, front-end polymerization is initiated by simultaneously irradiating the epoxy resin with three 365 nm UV light sources at the three initiation points determined in step A40 for 15 seconds to initiate multi-point front-end polymerization. After front-end initiation, the UV light sources are removed, and the polymerized front gradually diffuses outward from the initiation points until the resin is completely cured.

[0057] Example 2

[0058] This embodiment provides a method for efficiently manufacturing a composite material based on a front-end polymerization initiation point design, including steps S10, A20, A30, A40, and A50.

[0059] Step S10 in this embodiment is generally similar to that in Example 1 and will not be repeated here. The only difference is that in step S10 in this embodiment, the molar concentrations of the photoinitiator I-Sb and the thermal initiator TPED in the first mixed solution of I-Sb / TPED / EOM / BADGE finally prepared are both controlled to be 1.2 mol %.

[0060] Step A20 in this embodiment is generally similar to that in Example 1 and will not be repeated here. The only difference is that the discrete filler in step A20 in this embodiment is chopped glass fiber.

[0061] Step A30 in this embodiment is generally similar to that in embodiment 1 and will not be repeated here.

[0062] Step A40 in this embodiment: After the first epoxy resin front-end polymerization solution is poured into the mold, the number and position arrangement of the initiation points are designed based on the propagation speed of the polymerization front end according to the actual production requirements for curing time and energy consumption.

[0063] Among them, the number of initiation points is the ratio of the total energy consumption to the energy consumption of a single initiation point. When actual production requires the lowest energy consumption and curing time, the curing area of ​​the first epoxy resin front-end polymerization solution in the mold is approximated to a rectangular area of ​​length multiplied by width. All polymerization fronts start from the initiation point, and the area to be cured is divided into squares with equal side lengths along the length and width respectively, and the polymerization front is initiated at the center of the square at the same time.

[0064] Specifically in this embodiment, both energy consumption and curing time must be minimized. Figure 3 Schematic diagram of the trigger point arrangement design of embodiment 2 of the present invention. Figure 3 As shown, there are 6 in total, which are evenly distributed on the plane where the first epoxy resin front-end polymerization solution is located.

[0065] Step A50 in this embodiment is generally similar to that in embodiment 1 and will not be repeated.

[0066] Example 3

[0067] Figure 4 This is a flowchart of a method for efficiently manufacturing a composite material based on a front-end polymerization initiation point design according to Example 3 of the present invention.

[0068] like Figure 3 As shown, this embodiment provides a method for efficiently manufacturing composite materials based on front-end polymerization initiation point design, comprising the following steps:

[0069] S10, preparing a first mixed liquid of epoxy resin, diluent, photoinitiator and thermal initiator.

[0070] Step S10 in this embodiment is substantially the same as in Example 1 and will not be repeated. The only difference is that the molar concentrations of the photoinitiator I-Sb and the thermal initiator TPED in the first mixed solution of I-Sb / TPED / EOM / BADGE in step S10 in this embodiment are both 2 mol %, the molar ratio of the diluent EOM to the epoxy resin BADGE is 3:7.

[0071] B20, heating the first mixed solution to a preset initial temperature of 30° C. to 70° C. to obtain a second epoxy resin front-end polymerization solution.

[0072] The heating operation is achieved by an oven, a heating pad or a heating table.

[0073] Specifically in this embodiment, the preset initial temperature is selected to be 50° C., and the heating operation is achieved by a vacuum oven, which can perform a degassing treatment on the second epoxy resin front-end polymerization solution while heating and keeping the temperature.

[0074] B30, continuous fiber filler is laid in the mold.

[0075] The continuous fiber filler is a continuous fiber fabric, which includes any one or more of glass fiber, carbon fiber and plant fiber. The mass ratio of the continuous fiber filler to the second epoxy resin front-end polymerization solution is 5:95~35:65.

[0076] Specifically, in this embodiment, the continuous fiber filler is a rectangular glass fiber fabric of 140 mm×16 mm, and the glass fiber fabric is laid in the mold in a layered manner of [0]8.

[0077] B40, after pouring the second epoxy resin front-end polymerization solution into the mold, the number and position arrangement of the initiation points are designed based on the propagation speed of the polymerization front according to the actual production requirements for curing time and energy consumption.

[0078] Among them, the number of initiation points is the ratio of the total energy consumption to the energy consumption of a single initiation point. When actual production requires the lowest energy consumption and curing time, the curing area of ​​the second epoxy resin front-end polymerization solution in the mold is approximated to a rectangular area of ​​length multiplied by width. All polymerization fronts start from the initiation point, and the area to be cured is divided into squares with equal side lengths along the length and width respectively, and the polymerization front is initiated at the center of the square at the same time.

[0079] Specifically, in this embodiment, considering the mold's strip shape, the initiation points should be arranged along the propagation direction of the front polymerization, and the curing time must be less than 0.7 minutes. Through single-point initiation front polymerization experiments, the front polymerization propagation speed and curing time were calculated, and the curing time for single-point initiation was 1.2 minutes. Therefore, two-point initiation front polymerization can meet this requirement.

[0080] Figure 5 This is a schematic diagram of the trigger point arrangement design of Example 3 of the present invention. The trigger point arrangement design in this step is as follows Figure 4 As shown, there are two triggering points, which are arranged at both ends of the length direction of the rectangular mold.

[0081] After designing the number and position arrangement of the initiation points in this step, the entire mold is placed in a vacuum oven at 50° C. for a period of time to remove bubbles from the second epoxy resin front-end polymerization solution.

[0082] B50, initiates front-end polymerization, exothermic self-propagation and solidification.

[0083] Among them, the front-end polymerization is initiated at the initiation point by ultraviolet light irradiation or local heating. After the front-end is triggered, the ultraviolet light or heating point is removed, and the polymerization front propagates by itself due to the exothermic heat of the polymerization reaction. The second epoxy resin front-end polymerization solution is rapidly cured from the initiation point at a propagation rate of not less than 2.7 cm / min and the curing degree is greater than 95%, finally obtaining a fully cured epoxy resin-based composite material.

[0084] Specifically, in this embodiment, front-end polymerization is initiated by simultaneously irradiating the epoxy resin with two 365 nm UV light sources at the three initiation points determined in step B40 for 15 seconds to initiate multi-point front-end polymerization. After front-end initiation, the UV light sources are removed, and the polymerized front gradually diffuses outward from the initiation points until the resin is completely cured.

[0085] Comparative Example 1

[0086] In this comparative example, an epoxy resin cured product was prepared according to an efficient manufacturing method for a composite material based on a front-end polymerization initiation point design provided in Example 1.

[0087] The preparation method in this comparative example includes steps S10, A30, A40, and A50. (The addition of discrete fillers in step A20 is not performed.)

[0088] Step S10 in this comparative example is generally similar to that in Example 1 and will not be repeated here. The only difference is that in step S10 in this comparative example, the molar concentrations of the photoinitiator I-Sb and the thermal initiator TPED in the first mixed solution of I-Sb / TPED / EOM / BADGE finally prepared are both controlled to be 0.8 mol %.

[0089] Step A30 in this comparative example is substantially similar to that in Example 1 and will not be repeated here. The only difference is that the preset initial temperature in step A30 in this comparative example is 30°C.

[0090] Step A40 and step A50 in this comparative example are generally similar to those in the embodiment and will not be repeated.

[0091] Comparative Example 2

[0092] In this comparative example, an epoxy resin cured product was prepared according to an efficient manufacturing method for a composite material based on a front-end polymerization initiation point design provided in Example 1.

[0093] The preparation method in this comparative example includes steps S10, A30, A40, and A50. (The addition of discrete fillers in step A20 is not performed.)

[0094] Step S10 in this comparative example is generally similar to that in Example 1 and will not be repeated here. The only difference is that in step S10 in this comparative example, the molar concentrations of the photoinitiator I-Sb and the thermal initiator TPED in the first mixed solution of I-Sb / TPED / EOM / BADGE finally prepared are both controlled to be 0.8 mol %.

[0095] Step A30 in this comparative example is substantially similar to that in Example 1 and will not be repeated here. The only difference is that the preset initial temperature in step A30 in this comparative example is 30°C.

[0096] Step A40 in this comparative example is substantially similar to that in Example 1 and will not be repeated here. The only difference is that the number of triggering points in step A40 in this comparative example is only 1.

[0097] Step A50 in this comparative example is generally similar to that in the embodiment and will not be repeated.

[0098] Comparative Example 3

[0099] In this comparative example, an epoxy resin-based composite material was prepared according to an efficient composite material manufacturing method based on a front-end polymerization initiation point design provided in Example 3.

[0100] The preparation method in this comparative example includes steps S10, B20, B30, B40 and B50.

[0101] Steps S10, B20, B30, B40 and B50 in this comparative example are generally similar to those in Example 3 and will not be repeated here. The only difference is that the number of initiation points in this comparative example is 1.

[0102] Step B50 in this comparative example is generally similar to that in the embodiment and will not be repeated.

[0103] Comparative Example 4

[0104] This comparative example uses a traditional heat-curing method to form epoxy resin. The epoxy resin selected in this case is the same as that in the implementation case, except that 4,4′-diaminodiphenylmethane (DDM) is selected as the curing agent, and the epoxy resin is cured by heating at 100°C for 2 hours and 150°C for 2 hours.

[0105] Comparative Example 5

[0106] This comparative example uses a traditional thermal curing method to form an epoxy resin / glass fiber fabric composite material. The epoxy resin and fiber selected in this case are the same as those in Example 3. The difference is that 4,4′-diaminodiphenylmethane (DDM) is selected as the curing agent. The composite material is cured by heating at 100°C for 2 hours and 150°C for 2 hours.

[0107] Test Case

[0108] The composite materials prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4 and Comparative Example 5 were respectively recorded as Sample 1, Sample 2, Sample 3, Comparative Sample 1, Comparative Sample 2, Comparative Sample 3, Comparative Sample 4 and Comparative Sample 5.

[0109] Among them, sample 1 is an epoxy resin / carbon nanotube composite material, sample 2 is an epoxy resin / chopped glass fiber composite material, sample 3 is an epoxy resin / glass fiber fabric composite material, comparison samples 1 and comparison samples 2 are epoxy resins with different numbers of initiation points, comparison sample 3 is a single-point initiated epoxy resin / glass fiber fabric composite material, and comparison samples 4 and comparison samples 5 are epoxy resins and composite materials prepared by traditional thermal curing method.

[0110] This test example performs corresponding tests on Sample 1, Sample 2, Sample 3, Comparative Sample 1, Comparative Sample 2, Comparative Sample 3, Comparative Sample 4, and Comparative Sample 5.

[0111] Figure 6 is a SEM image of comparative sample 1 of the test example of the present invention.

[0112] like Figure 6 As shown in Figure 1, the internal structure of the front-end polymerized epoxy resin of Comparative Sample 1 is dense and has no obvious pores. Therefore, the front-end polymerization has little effect on the microscopic morphology of the epoxy resin.

[0113] Figure 7 3 is a comparison of the bending properties of the comparative samples 1 and 2 of the test examples of the present invention.

[0114] like Figure 7As shown in the figure, the flexural properties of the front-end polymerized epoxy resin in Comparative Sample 1 are significantly higher than those of the single-point initiated front-end polymerized epoxy resin in Comparative Sample 2. The high front-end temperature at the merging location increases the crosslinking density of the epoxy resin, effectively improving its mechanical properties. The high front-end temperature in the front merging area increases the crosslinking density of the epoxy resin, further improving its flexural strength.

[0115] Figure 8 3 is a comparison of the bending properties of the test example sample 3 of the present invention and the comparative sample 3.

[0116] like Figure 8 As shown in the figure, when continuous fillers are added, the flexural strength of sample 3 with multi-point initiation does not decrease significantly compared with the control sample 3 with single-point initiation (multi-point initiation has little effect on the mechanical properties of the composite material).

[0117] like Figure 7 and Figure 8 As shown in the figure, the flexural properties of the front-end polymerized epoxy resin-based composite material of sample 3 are significantly improved compared with the front-end polymerized epoxy resin of comparison sample 1, and the addition of fibers effectively improves the mechanical properties of the sample.

[0118] In this test example, using the DSC method, the curing degrees of Samples 1, 2, and 3 obtained by multi-point front-end polymerization were calculated to be 97.3%, 98.1%, and 96.9%, respectively. The above data indicate that the curing degrees of the composite materials of Samples 1, 2, and 3 were all above 95%, demonstrating that the multi-point front-end polymerization epoxy resin and composite material prepared by the embodiment of the high-efficiency composite material manufacturing method based on front-end polymerization initiation point design can achieve complete curing.

[0119] This test example also tested the curing time and energy consumption of Samples 1, 2, and 3. The test results are as follows: Sample 1 had a curing time of 1.92 minutes and an energy consumption of 2025 J; Sample 2 had a curing time of 0.88 minutes and an energy consumption of 4050 J; and Sample 3 had a curing time of 0.63 minutes and an energy consumption of 1350 J. These data indicate that the epoxy resin composites of Samples 1, 2, and 3 were cured within 3 minutes, with an energy consumption of less than 5000 J. The curing time and energy consumption of Comparative Sample 4 were 4 hours and 43.2 MG, respectively, and the curing time and energy consumption of Comparative Sample 5 were also 4 hours and 43.2 MG. Therefore, through front-end polymerization in this embodiment, the curing time of traditional epoxy resins and composites was shortened from several hours to several minutes, and the energy consumption was reduced from several hours of high-temperature input to 15 seconds of UV energy input.

[0120] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for efficiently manufacturing composite materials based on front-end polymerization initiation point design, characterized in that: The following steps are involved: S10, preparing a first mixed solution of an epoxy resin, a diluent, a photoinitiator, and a thermal initiator, wherein the molar concentration of the photoinitiator in the first mixed solution is 0.5 mol% to 5.5 mol%, the molar concentration of the thermal initiator in the first mixed solution is 0.5 mol% to 5.5 mol%, the molar ratio of the diluent to the epoxy resin is (2-3):(7-8), the photoinitiator is 4-(octyloxyphenyl)phenyliodine hexafluoroantimonate and / or tetraalkyl(perfluoro-tert-butyloxy)aluminate anion, the thermal initiator is benzopinacol, and the epoxy resin is bisphenol A diglycidyl ester; A20, adding a discrete filler to the first mixed solution and mixing uniformly to obtain a second mixed solution, wherein the discrete filler is a reinforcing and functional filler, and the mass fraction of the discrete filler in the second mixed solution is 0.5 wt% to 35 wt%; A30, heating the second mixed solution to a preset initial temperature of 30° C. to 70° C. to obtain a first epoxy resin front-end polymerization solution, and performing a vacuum degassing treatment on the first epoxy resin front-end polymerization solution; A40, after pouring the first epoxy resin front-end polymer solution into the mold, the number and positional arrangement of initiation points are designed based on the actual production requirements for curing time and energy consumption and the propagation speed of the polymerization front. The number of initiation points is the ratio of the total energy consumption to the energy consumption of each initiation point. When the actual production requirements for energy consumption and curing time are both minimized, the curing area of ​​the first epoxy resin front-end polymer solution in the mold is approximated to a rectangular area of ​​length times width. All polymerization fronts initiate from the initiation point. The area to be cured is divided into squares of equal length along the length and width, respectively. The polymerization front is simultaneously initiated at the center of the square. A50, by means of ultraviolet light irradiation or local heating, the front-end polymerization is initiated at the position of the initiation point. After the front-end is initiated, the ultraviolet light or the heating point is removed, and multiple polymerization front ends spread simultaneously by self-propagation due to the exothermic heat of the polymerization reaction. The first epoxy resin front-end polymerization solution is rapidly cured from the initiation point at a propagation rate of not less than 2.5 cm / min and the curing degree is greater than 95%, and finally a completely cured epoxy resin is obtained.

2. A method for efficiently manufacturing composite materials based on front-end polymerization initiation point design, characterized in that: The following steps are involved: S10, preparing a first mixed solution of an epoxy resin, a diluent, a photoinitiator, and a thermal initiator, wherein the molar concentration of the photoinitiator in the first mixed solution is 0.5 mol% to 5.5 mol%, the molar concentration of the thermal initiator in the first mixed solution is 0.5 mol% to 5.5 mol%, the molar ratio of the diluent to the epoxy resin is (2-3):(7-8), the photoinitiator is 4-(octyloxyphenyl)phenyliodine hexafluoroantimonate and / or tetraalkyl(perfluoro-tert-butyloxy)aluminate anion, the thermal initiator is benzopinacol, and the epoxy resin is bisphenol A diglycidyl ester; B20, heating the first mixed solution to a preset initial temperature of 30° C. to 70° C. to obtain a second epoxy resin front-end polymerization solution; B30, laying a continuous fiber filler in a mold, wherein the continuous fiber filler is a continuous fiber fabric, and the mass ratio of the continuous fiber filler to the second epoxy resin front-end polymerization solution is 5:95 to 35:65; B40, after pouring the second epoxy resin front-end polymer solution into the mold, vacuum degassing the second epoxy resin front-end polymer solution, and designing the number and positional arrangement of initiation points based on the actual production requirements for curing time and energy consumption and the propagation speed of the polymerization front. The number of initiation points is the ratio of the total energy consumption to the energy consumption of each initiation point. When the actual production requirements for energy consumption and curing time are both minimized, the curing area of ​​the second epoxy resin front-end polymer solution in the mold is approximated to a rectangular area whose length is multiplied by the width. All polymerization fronts initiate from the initiation point. The area to be cured is divided into squares of equal length along the length and width, respectively, and the polymerization front is simultaneously initiated at the center of the square. B50, by means of ultraviolet light irradiation or local heating, the front-end polymerization is initiated at the position of the initiation point. After the front-end is initiated, the ultraviolet light or the heating point is removed, and multiple polymerization fronts spread simultaneously by self-propagation due to the exothermic heat of the polymerization reaction. The second epoxy resin front-end polymerization solution is rapidly cured from the initiation point at a propagation rate of not less than 2.7 cm / min and the curing degree is greater than 95%, thereby finally obtaining a fully cured epoxy resin-based composite material.

3. The method for efficiently manufacturing composite materials based on front-end polymerization initiation point design according to claim 1 or 2, characterized in that: in, Step S10 includes the following sub-steps: S11, adding a photoinitiator and a thermal initiator into an organic solvent and stirring at high speed until dissolved to obtain an initiator solution; S12, adding epoxy resin and diluent into the initiator solution and mixing them evenly, then draining the organic solvent to obtain a first mixed solution.

4. The method for efficiently manufacturing composite materials based on front-end polymerization initiation point design according to claim 3, characterized in that: in, In step S11, the organic solvent includes dichloromethane and / or ethyl acetate.

5. The method for efficiently manufacturing composite materials based on front-end polymerization initiation point design according to claim 1 or 2, characterized in that: in, In step S10, the diluent includes any one or more of 3-ethyl-3-oxetanol, glycidyl ester neopentyl glycol diglycidyl ester, hexanediol diglycidyl ester, cyclohexanedimethanol and cyclohexyl epoxy ester.

6. The method for efficiently manufacturing composite materials based on front-end polymerization initiation point design according to claim 1 or 2, characterized in that: in, In step S10, the molar ratio of the photoinitiator to the thermal initiator is 1:0.5 to 1:

2.

7. The method for efficiently manufacturing composite materials based on front-end polymerization initiation point design according to claim 1 or 2, characterized in that: in, In step A30 or step B20, the heating operation is achieved by an oven, a heating pad or a heating table.

8. The method for efficiently manufacturing composite materials based on front-end polymerization initiation point design according to claim 1 or 2, characterized in that: in, In step A50 or step B50, when the method of initiating front-end polymerization is ultraviolet light irradiation, the wavelength of the ultraviolet light source is 365 nm, and the irradiation time is 15 s to 20 s. When the method of inducing the front-end polymerization is local heating, the local heating can be achieved by means of electric soldering iron heating or laser heating.

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