Lightweight high-strength epoxy resin foam material and preparation method thereof

Abstract

The invention relates to the technical field of foamed plastics, and particularly discloses a lightweight high-strength epoxy resin foam material and a preparation method thereof, the lightweight high-strength epoxy resin foam material comprises the following raw materials by weight: 94-106 parts of a modified epoxy prepolymer, 1.2-1.6 parts of an initiator, 16-18 parts of a curing agent, 0.9-1.2 parts of a foaming agent, 0.6-0.9 part of an antioxidant and 6-10 parts of a functional filler; the functional filler and the modified epoxy prepolymer are added, the functional filler is composed of a core-shell structure, the outer layer of the functional filler is a modifier structure obtained through a ring-opening reaction of a carboxyl monomer and epoxy sepiolite, the inner core of the functional filler is modified rubber powder, and the modifier structure contains a sepiolite structure, a pyrimidine ring, a benzene ring and a sepiolite structure. The epoxy resin not only can participate in the curing reaction of epoxy resin, but also can generate chemical crosslinking with the modified epoxy prepolymer, so that the mechanical property, heat resistance and ultraviolet resistance of the material are improved.

Description

Technical Field

[0001] This application relates to the technical field of foamed plastics, and more specifically, it relates to a lightweight and high-strength epoxy resin foam material and a preparation method thereof. Background Art

[0002] Epoxy foaming materials have been widely used in important fields such as thermal insulation, electronics, aviation, and ships due to their good thermal stability, mechanical properties, insulation properties, heat insulation properties, light weight, and low cost.

[0003] Epoxy resin is a thermosetting material with a high degree of crosslinking. After curing, it has a three-dimensional network structure in space. The molecular chains are not easy to slide, and there is a large internal stress. There are disadvantages such as insufficient toughness and easy cracking. To improve the impact resistance of epoxy resin-based foam materials, rubber elastomers are commonly used as toughening materials in the prior art. However, due to the structural characteristics of rubber molecules, their compatibility with epoxy resin is poor, which will significantly reduce the heat resistance, material modulus, and fracture strength of the composite material. At the same time, the epoxy foaming material itself also has the problem of poor ultraviolet resistance.

[0004] Therefore, providing an epoxy resin foam material with high mechanical properties, good heat resistance, and good ultraviolet resistance is a technical problem that needs to be solved at present. Summary of the Invention

[0005] In order to solve the technical problems of poor mechanical properties, heat resistance, and ultraviolet resistance of the existing epoxy resin foam materials, this application provides a lightweight and high-strength epoxy resin foam material and a preparation method thereof.

[0006] A lightweight and high-strength epoxy resin foam material, comprising the following raw materials in parts by weight: 94 - 106 parts of modified epoxy prepolymer, 1.2 - 1.6 parts of initiator, 16 - 18 parts of curing agent, 0.9 - 1.2 parts of foaming agent, 0.6 - 0.9 parts of antioxidant, and 6 - 10 parts of functional filler; Mix the modified epoxy prepolymer, initiator, and curing agent evenly, add the foaming agent, antioxidant, and functional filler, stir for 16 - 18 min, heat up to 76 - 82 °C, stir and react for 1.8 - 2.4 h, then place it in a mixer at 100 - 110 °C for 9 - 14 min, heat up to 137 - 143 °C, pre-cure for 110 - 130 min, and then heat up to 178 - 182 °C for foaming for 14 - 20 min to obtain the lightweight and high-strength epoxy resin foam material.

[0007] Preferably, the initiator is azobisisobutyronitrile or azobisisoheptonitrile.

[0008] Preferably, the curing agent is dicyandiamide or diaminodiphenyl sulfone.

[0009] Preferably, the blowing agent is azodicarbonamide or 4,4'-oxybis(benzenesulfonyl hydrazide).

[0010] Preferably, the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite or dilauryl thiodipropionate.

[0011] Preferably, the modified epoxy prepolymer is prepared by the following steps: Step A1: Mix deionized water, absolute ethanol and octylphenol polyoxyethylene ether evenly, add lignin, stir and mix for 12 - 18 min, adjust the pH to 3 - 4, dropwise add KH-560, control the dropping within 30 min, after dropping, raise the temperature to 46 - 54 °C, stir and react for 12 - 24 h, centrifuge, wash and dry the precipitate to obtain epoxy lignin, wherein the mass ratio of deionized water, absolute ethanol, octylphenol polyoxyethylene ether, lignin and KH-560 is 32 - 46:90 - 100:1.2 - 1.6:8:0.8 - 1.2; Step A2: Ultrasonically disperse epoxy lignin and anhydrous DMF, dropwise add a mixture a of trifluoromethanesulfonic acid, diallylamine and anhydrous DMF. After the dropping is completed, raise the temperature to 78 - 84 °C and stir for 2 - 3 h. After the reaction is completed, centrifuge, wash and dry the precipitate to obtain modified lignin. Among them, the mass ratio of epoxy lignin, anhydrous DMF and mixture a is 3.6 - 4.4:72 - 86:26 - 32. In mixture a, the mass ratio of trifluoromethanesulfonic acid, diallylamine and anhydrous DMF is 0.4 - 0.6:1.0 - 1.4:24 - 30. In the above reaction process, using anhydrous DMF as the solvent and trifluoromethanesulfonic acid as the catalyst, the epoxy group on epoxy lignin and the amino group on diallylamine undergo a ring-opening reaction to obtain modified lignin; Step A3: Add modified lignin into deionized water, adjust the pH to 10 - 11, stir evenly, then add epichlorohydrin and cetyltrimethylammonium bromide, raise the temperature to 58 - 64 °C, stir and react for 3.2 - 4.4 h. After the reaction is completed, precipitate and dry to obtain the modified epoxy prepolymer, wherein the mass ratio of modified lignin, deionized water, epichlorohydrin and cetyltrimethylammonium bromide is 3.5:60 - 70:42 - 46:0.42 - 0.56. Using cetyltrimethylammonium bromide as the catalyst, the hydroxyl group on modified lignin and the chlorine atom on epichlorohydrin undergo a nucleophilic substitution reaction to obtain the modified epoxy prepolymer.

[0012] Preferably, the functional filler is prepared by the following steps: Step B1: Grind waste tires to pass through a 30 - 50 mesh sieve, then soak them in an aqueous sodium hydroxide solution for 24 h, wash until neutral, and dry to obtain alkali - treated rubber powder; Mix the alkali - treated rubber powder and an aqueous hydrogen peroxide solution evenly, adjust the pH to 4.2 - 5.6, heat up to 46 - 54 °C, stir and react for 5.4 - 6.2 h, filter while it is hot, wash and dry the filter cake to obtain modified rubber powder; Among them, the mass ratio of waste tire powder to the aqueous sodium hydroxide solution is 12:80 - 120, the mass fraction of the aqueous sodium hydroxide solution is 18 - 22%, the mass ratio of the alkali - treated rubber powder to the aqueous hydrogen peroxide solution is 8:160 - 180, and the mass fraction of the aqueous hydrogen peroxide solution is 3 - 5%. Through alkali treatment, dust, stearate, stabilizers, etc. on the rubber surface can be removed. Then, under acidic conditions, the unsaturated carbon - carbon double bonds on the surface of rubber particles are oxidized by the aqueous hydrogen peroxide solution to form carbonyl groups. The carbonyl oxygen has strong electron - withdrawing properties and is prone to nucleophilic addition reactions on carbon atoms; Step B2: Ultrasonically disperse the modified rubber powder and the modifier in anhydrous DMF, heat up to 56 - 62 °C, stir for 10 - 14 h, carry out rotary evaporation, wash, and dry to obtain functional filler. Among them, the mass ratio of the modified rubber powder, the modifier, and anhydrous DMF is 2 - 4:6.5 - 8.7:66 - 74. During the above - mentioned reaction process, using anhydrous DMF as the solvent, the active hydroxyl groups on the modifier can form hydrogen - bond interactions with the oxygen - containing functional groups on the modified rubber powder, and then coat the surface of the modified rubber powder to obtain functional filler.

[0013] Preferably, the modifier is prepared by the following steps: Step C1: Add 3 - (chloromethyl) benzoic acid to anhydrous ethanol, heat up to 40 - 46 °C, stir evenly, then add a mixture b of N,N'-dicyclohexylcarbodiimide, 4 - dimethylaminopyridine, 4,6 - diamino - pyrimidine, and anhydrous ethanol, control the dropping to be completed within 15 min, heat up to reflux, stir and react for 4 - 6 h. After the reaction is completed, centrifuge, wash and dry the precipitate to obtain phenyl monomer. Among them, the mass ratio of 3 - (chloromethyl) benzoic acid, anhydrous ethanol, and mixture b is 3 - 5:64 - 72:32 - 40. In mixture b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4 - dimethylaminopyridine, 4,6 - diamino - pyrimidine, and anhydrous ethanol is 4.1 - 6.9:2.2 - 3.6:1.6 - 3.2:40 - 46. During the above - mentioned reaction process, using N,N'-dicyclohexylcarbodiimide as the dehydrating agent and 4 - dimethylaminopyridine as the acylating agent, the carboxyl group on 3 - (chloromethyl) benzoic acid reacts with the amino group on 4,6 - diamino - pyrimidine to carry out amidation reaction to obtain phenyl monomer. During the reaction process, control the amount of substance of 4,6 - diamino - pyrimidine to be slightly higher than the amount of substance of 3 - (chloromethyl) benzoic acid, so that after the reaction is completed, the carboxyl group can be fully consumed, and at the same time, there are still remaining amino groups that can participate in the subsequent reaction process; Step C2: Add phenyl monomer, p-hydroxycinnamic acid, triethylamine and toluene into anhydrous DMF, stir evenly, under nitrogen protection, heat up to reflux, stir and react for 5 - 8 h. After the reaction is completed, filter, rotary evaporate the filtrate. After the rotary evaporation product is dissolved in acetone, filter, rotary evaporate the filtrate, wash and dry to obtain the carboxyl monomer. Among them, the mass ratio of phenyl monomer, p-hydroxycinnamic acid, triethylamine, toluene, anhydrous DMF and acetone is 2.6 - 4.4:1.6 - 2.8:0.2 - 0.4:26 - 34:86 - 92:20 - 24. During the above reaction process, using anhydrous DMF as the solvent, triethylamine as the catalyst, and toluene as the dehydrating agent, the hydroxyl group on the phenyl monomer undergoes a nucleophilic substitution reaction with the active chlorine atom on p-hydroxycinnamic acid to obtain the carboxyl monomer; Step C3: Add sepiolite into the hydrochloric acid aqueous solution, heat up to 42 - 46 °C, stir evenly, add KH-560, heat up to 54 - 62 °C, stir and react for 4.6 - 5.8 h, centrifuge, wash and dry the precipitate to obtain epoxidized sepiolite; ultrasonically disperse the epoxidized sepiolite and anhydrous DMF, dropwise add the mixed solution c of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF, control to finish dropping in 12 min. After dropping, heat up to 108 - 112 °C, stir for 2.6 - 3.4 h. After the reaction is completed, centrifuge, wash and dry the precipitate to obtain the modifier. Among them, the mass ratio of sepiolite, hydrochloric acid aqueous solution and KH-560 is 3.4 - 4.4:26 - 32:0.6 - 0.8, the mass ratio of epoxidized sepiolite, anhydrous DMF and mixed solution c is 4:56 - 62:12. In the mixed solution c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF is 0.2:1.0 - 1.4:16 - 20, and the mass fraction of the hydrochloric acid aqueous solution is 12 - 16%. During the above reaction process, using the hydrochloric acid aqueous solution as the solvent, tetrabutylammonium bromide as the catalyst, the carboxyl monomer and epoxidized sepiolite undergo a ring-opening esterification reaction to obtain the modifier.

[0014] In summary, the present application has the following beneficial effects: In order to improve the mechanical properties, heat resistance and ultraviolet resistance of epoxy resin foam materials, the present invention starts from two aspects. One is to add functional fillers. The functional fillers are composed of a core-shell structure. The outer layer is a modifier structure obtained by ring-opening reaction of carboxyl monomers and epoxy sepiolite, and the inner core is modified rubber powder. The modifier structure contains a sepiolite structure, a pyrimidine ring and a benzene ring. The presence of the sepiolite structure, on the one hand, together with the rigid benzene ring and pyrimidine ring, improves the heat resistance and ultraviolet resistance of the foam material. On the other hand, sepiolite and pyrimidine ring can form hydrogen bond interactions with modified rubber powder and modified epoxy prepolymer, improving the compatibility of the functional filler with the modified epoxy prepolymer and further enhancing the mechanical properties of the epoxy resin foam material. The oxygen-containing functional groups on the modified rubber powder can not only form hydrogen bond interactions with the modified epoxy prepolymer, but also produce chemical cross-linking with the modified epoxy prepolymer, further improving the mechanical properties, heat resistance and ultraviolet resistance of the epoxy resin foam material. The other is to add a modified epoxy prepolymer. On the one hand, the grafted unsaturated double bonds on it can undergo chemical cross-linking with the modified epoxy prepolymer, improving the compatibility of the functional filler with the modified epoxy prepolymer and further enhancing the mechanical properties of the epoxy resin foam material. On the other hand, the lignin structure grafted on the surface of modified nano-titanium dioxide has a fused polycyclic rigid structure with high rigidity, good heat resistance and excellent ultraviolet resistance. Introducing it into the epoxy resin foam material can cooperate with the functional filler to jointly improve the mechanical properties, heat resistance and ultraviolet resistance of the epoxy resin foam material. Detailed Embodiments

[0015] To make the embodiments of the present application easier to understand, the following will detail the present application with specific examples. These examples are for illustrative purposes only and are not limited to the application scope of the present application.

[0016] The main raw materials and their component contents used in the examples and comparative examples are as follows: The waste tire is rubber particles produced by Pengxia Furnace Lining Material Factory in Lingshou County, with a wear rate of 0.01%. The sepiolite is produced by Xinglei Sepiolite Co., Ltd. in Neixiang County, with a water content ≤ 0.01%. The lignin is produced by Pand (Shanghai) International Trading Co., Ltd., with a CAS number of 8068-03-9.

[0017] Preparation Examples 1-3 and Comparative Preparation Examples 1-2 provide a modifier.

[0018] Preparation Example 1 This preparation example provides a modifier, which is prepared by the following steps: Step C1: Add 3-(chloromethyl)benzoic acid into absolute ethanol, heat up to 40 °C, stir for 16 min at a rotation speed of 600 rpm until uniform, then add the mixed solution b of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol, control to finish dropping within 15 min, heat up to reflux, stir and react for 4 h. After the reaction is completed, centrifuge, wash the precipitate 3 times with absolute ethanol and deionized water, and dry at 55 °C to constant weight to obtain the phenyl monomer. Among them, the mass ratio of 3-(chloromethyl)benzoic acid, absolute ethanol and the mixed solution b is 3:64:32. In the mixed solution b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol is 4.1:2.2:1.6:40; Step C2: Add the phenyl monomer, p-hydroxycinnamic acid, triethylamine and toluene into anhydrous DMF, stir for 12 min at a rotation speed of 650 rpm until uniform. Under nitrogen protection, heat up to reflux, maintain the rotation speed unchanged, and continue to stir and react for 5 h. After the reaction is completed, filter, control the rotary evaporation temperature to be 82 °C, rotary evaporate to remove anhydrous DMF. After the rotary evaporation product is dissolved in acetone, filter, control the rotary evaporation temperature to be 34 °C, rotary evaporate to remove acetone, and then wash 3 times with absolute ethanol and deionized water in sequence, and dry at 65 °C to constant weight to obtain the carboxyl monomer. Among them, the mass ratio of the phenyl monomer, p-hydroxycinnamic acid, triethylamine, toluene, anhydrous DMF and acetone is 2.6:1.6:0.2:26:86:20; Step C3: Add sepiolite into the hydrochloric acid aqueous solution, heat up to 42 °C, control the rotation speed to be 720 rpm and stir for 14 min until uniform, add KH-560, heat up to 54 °C, maintain the rotation speed unchanged, and continue to stir and react for 4.6 h. Centrifuge, wash the precipitate 3 times with absolute ethanol and deionized water in sequence, and dry at 64 °C to constant weight to obtain epoxidized sepiolite; Ultrasonically disperse the epoxidized sepiolite and anhydrous DMF, control the ultrasonic frequency to be 25 kHz, the ultrasonic power to be 400 w, and ultrasonicate for 14 min. At a rotation speed of 600 rpm, while stirring, dropwise add the mixed solution c of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF, control to finish dropping within 12 min. After dropping, heat up to 108 °C, maintain the rotation speed unchanged, and stir for 2.6 h. After the reaction is completed, centrifuge, wash the precipitate 3 times with a 32% ethanol solution by mass fraction, and dry at 60 °C to constant weight to obtain the modifier. Among them, the mass ratio of sepiolite, hydrochloric acid aqueous solution and KH-560 is 3.4:26:0.6. The mass ratio of epoxidized sepiolite, anhydrous DMF and the mixed solution c is 4:56:12. In the mixed solution c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF is 0.2:1.0:16, and the mass fraction of the hydrochloric acid aqueous solution is 12%.

[0019] Preparation Example 2 This preparation example provides a modifier, which is prepared by the following steps: Step C1: Add 3-(chloromethyl)benzoic acid into absolute ethanol, heat up to 43 °C, stir for 20 min at a rotation speed of 680 rpm until homogeneous, then add the mixed solution b of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol, control the dropping within 15 min, heat up to reflux, stir and react for 5 h. After the reaction is completed, centrifuge, wash the precipitate 3 times with absolute ethanol and deionized water, and dry at 60 °C to constant weight to obtain the phenyl monomer. Among them, the mass ratio of 3-(chloromethyl)benzoic acid, absolute ethanol and the mixed solution b is 4:68:36. In the mixed solution b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol is 5.5:2.9:2.4:43; Step C2: Add the phenyl monomer, p-hydroxycinnamic acid, triethylamine and toluene into anhydrous DMF, stir for 10 min at a rotation speed of 700 rpm until homogeneous. Under nitrogen protection, heat up to reflux, maintain the rotation speed unchanged, and continue to stir and react for 6.5 h. After the reaction is completed, filter, control the rotary evaporation temperature at 84 °C, rotary evaporate to remove anhydrous DMF. After the rotary evaporation product is dissolved in acetone, filter, control the rotary evaporation temperature at 36 °C, rotary evaporate to remove acetone, and then wash 4 times with absolute ethanol and deionized water in sequence, and dry at 70 °C to constant weight to obtain the carboxyl monomer. Among them, the mass ratio of the phenyl monomer, p-hydroxycinnamic acid, triethylamine, toluene, anhydrous DMF and acetone is 3.5:2.2:0.3:30:89:22; Step C3: Add sepiolite into the hydrochloric acid aqueous solution, heat up to 44 °C, control the rotation speed at 740 rpm and stir for 17 min until homogeneous, add KH-560, heat up to 58 °C, maintain the rotation speed unchanged, and continue to stir and react for 5.2 h. Centrifuge, wash the precipitate 4 times with absolute ethanol and deionized water in sequence, and dry at 68 °C to constant weight to obtain epoxidized sepiolite; Ultrasonically disperse the epoxidized sepiolite and anhydrous DMF, control the ultrasonic frequency at 30 kHz and the ultrasonic power at 450 w, ultrasonic for 18 min. At a rotation speed of 640 rpm, while stirring, dropwise add the mixed solution c of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF, control the dropping within 12 min. After dropping, heat up to 110 °C, maintain the rotation speed unchanged, and continue to stir for 3.0 h. After the reaction is completed, centrifuge, wash the precipitate 4 times with a 36% ethanol solution by mass fraction, and dry at 62 °C to constant weight to obtain the modifier. Among them, the mass ratio of sepiolite, hydrochloric acid aqueous solution and KH-560 is 3.9:29:0.7, the mass ratio of epoxidized sepiolite, anhydrous DMF and the mixed solution c is 4:59:12. In the mixed solution c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF is 0.2:1.2:18, and the mass fraction of the hydrochloric acid aqueous solution is 14%.

[0020] Preparation Example 3 This preparation example provides a modifier, which is prepared by the following steps: Step C1: Add 3-(chloromethyl)benzoic acid into absolute ethanol, heat up to 46 °C, stir for 24 min until homogeneous at a rotation speed of 710 rpm, then add a mixed solution b of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol, control the dropping within 15 min, heat up to reflux, stir and react for 6 h. After the reaction is completed, centrifuge, wash the precipitate 5 times with absolute ethanol and deionized water, and dry at 65 °C to constant weight to obtain a phenyl monomer. Among them, the mass ratio of 3-(chloromethyl)benzoic acid, absolute ethanol and the mixed solution b is 5:72:40. In the mixed solution b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol is 6.9:3.6:3.2:46; Step C2: Add the phenyl monomer, p-hydroxycinnamic acid, triethylamine and toluene into anhydrous DMF, stir for 8 min until homogeneous at a rotation speed of 750 rpm. Under nitrogen protection, heat up to reflux, maintain the rotation speed unchanged, and continue to stir and react for 8 h. After the reaction is completed, filter, control the rotary evaporation temperature at 86 °C, rotary evaporate to remove anhydrous DMF. After the rotary evaporation product is dissolved in acetone, filter, control the rotary evaporation temperature at 40 °C, rotary evaporate to remove acetone, and then wash 5 times with absolute ethanol and deionized water in sequence, and dry at 75 °C to constant weight to obtain a carboxyl monomer. Among them, the mass ratio of the phenyl monomer, p-hydroxycinnamic acid, triethylamine, toluene, anhydrous DMF and acetone is 4.4:2.8:0.4:34:92:24; Step C3: Add sepiolite into the hydrochloric acid aqueous solution, heat up to 46 °C, stir at a rotation speed of 760 rpm for 20 min until homogeneous, add KH-560, heat up to 62 °C, keep the rotation speed unchanged, continue to stir and react for 5.8 h, centrifuge, wash the precipitate with absolute ethanol and deionized water 5 times each, dry at 72 °C to constant weight to obtain epoxidized sepiolite; ultrasonically disperse the epoxidized sepiolite and anhydrous DMF, control the ultrasonic frequency at 35 kHz, ultrasonic power at 500 w, ultrasonicate for 22 min, while stirring at a rotation speed of 680 rpm, dropwise add the mixed solution c of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF, control to finish dropping in 12 min, after dropping, heat up to 112 °C, keep the rotation speed unchanged, continue to stir for 3.4 h, after the reaction ends, centrifuge, wash the precipitate with 40% ethanol solution by mass 5 times, dry at 64 °C to constant weight to obtain the modifier. Among them, the mass ratio of sepiolite, hydrochloric acid aqueous solution and KH-560 is 4.4:32:0.8, the mass ratio of epoxidized sepiolite, anhydrous DMF and mixed solution c is 4:62:12, in the mixed solution c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF is 0.2:1.4:20, and the mass fraction of the hydrochloric acid aqueous solution is 16%.

[0021] Comparative Preparation Example 1 This comparative preparation example provides a modifier, which is prepared by the following steps: Step C1: Add 3-(chloromethyl)benzoic acid into absolute ethanol, heat up to 40 °C, stir at a rotation speed of 600 rpm for 16 min until homogeneous, then add the mixed solution b of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, m-phenylenediamine and absolute ethanol, control to finish dropping in 15 min, heat up to reflux, stir and react for 4 h, after the reaction ends, centrifuge, wash the precipitate with absolute ethanol and deionized water 3 times each, dry at 55 °C to constant weight to obtain the phenyl monomer. Among them, the mass ratio of 3-(chloromethyl)benzoic acid, absolute ethanol and mixed solution b is 3:64:32, and in the mixed solution b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, m-phenylenediamine and absolute ethanol is 4.1:2.2:1.6:40; Step C2: Add the phenyl monomer, p-hydroxycinnamic acid, triethylamine and toluene into anhydrous DMF, stir at a rotation speed of 650 rpm for 12 min until homogeneous, under nitrogen protection, heat up to reflux, keep the rotation speed unchanged, continue to stir and react for 5 h, after the reaction ends, filter, control the rotary evaporation temperature at 82 °C, rotary evaporate to remove anhydrous DMF, dissolve the rotary evaporation product in acetone, then filter, control the rotary evaporation temperature at 34 °C, rotary evaporate to remove acetone, and then wash with absolute ethanol and deionized water 3 times each, dry at 65 °C to constant weight to obtain the carboxyl monomer. Among them, the mass ratio of the phenyl monomer, p-hydroxycinnamic acid, triethylamine, toluene, anhydrous DMF and acetone is 2.6:1.6:0.2:26:86:20; Step C3: Add sepiolite into the hydrochloric acid aqueous solution, heat up to 42 °C, stir at a rotation speed of 720 rpm for 14 min until homogeneous, add KH-560, heat up to 54 °C, keep the rotation speed unchanged, continue to stir and react for 4.6 h, centrifuge, wash the precipitate with absolute ethanol and deionized water three times respectively, and dry at 64 °C until constant weight to obtain epoxidized sepiolite; ultrasonically disperse the epoxidized sepiolite and anhydrous DMF, control the ultrasonic frequency at 25 kHz, ultrasonic power at 400 w, ultrasonic for 14 min, while stirring at a rotation speed of 600 rpm, dropwise add the mixture c of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF, control to finish dropping in 12 min, after dropping, heat up to 108 °C, keep the rotation speed unchanged, stir for 2.6 h, after the reaction ends, centrifuge, wash the precipitate with 32% ethanol solution by mass three times, and dry at 60 °C until constant weight to obtain the modifier. Among them, the mass ratio of sepiolite, hydrochloric acid aqueous solution and KH-560 is 3.4:26:0.6, the mass ratio of epoxidized sepiolite, anhydrous DMF and mixture c is 4:56:12, in mixture c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF is 0.2:1.0:16, and the mass fraction of the hydrochloric acid aqueous solution is 12%.

[0022] Comparative Preparation Example 2 This comparative preparation example provides a modifier, which is prepared by the following steps: Step C1: Add 3-(chloromethyl)benzoic acid into absolute ethanol, heat up to 40 °C, stir at a rotation speed of 600 rpm for 16 min until homogeneous, then add the mixture b of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol, control to finish dropping in 15 min, heat up to reflux, stir and react for 4 h, after the reaction ends, centrifuge, wash the precipitate with absolute ethanol and deionized water three times respectively, and dry at 55 °C until constant weight to obtain the phenyl monomer. Among them, the mass ratio of 3-(chloromethyl)benzoic acid, absolute ethanol and mixture b is 3:64:32, in mixture b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and absolute ethanol is 4.1:2.2:1.6:40; Step C2: Add phenyl monomer, p-hydroxybenzoic acid, triethylamine, and toluene into anhydrous DMF, stir at 650 rpm for 12 min until homogeneous, under nitrogen protection, heat up to reflux, maintain the rotation speed unchanged, continue to stir and react for 5 h. After the reaction, filter, control the rotary evaporation temperature at 82 °C, rotary evaporate until anhydrous DMF is removed. After the rotary evaporation product is dissolved in acetone, filter, control the rotary evaporation temperature at 34 °C, rotary evaporate until acetone is removed, then wash with anhydrous ethanol and deionized water three times in sequence, and dry at 65 °C to constant weight to obtain the carboxyl monomer. Among them, the mass ratio of phenyl monomer, p-hydroxybenzoic acid, triethylamine, toluene, anhydrous DMF, and acetone is 2.6:1.6:0.2:26:86:20; Step C3: Add sepiolite into the hydrochloric acid aqueous solution, heat up to 42 °C, control the rotation speed at 720 rpm and stir for 14 min until homogeneous, add KH-560, heat up to 54 °C, maintain the rotation speed unchanged, continue to stir and react for 4.6 h, centrifuge, wash the precipitate with anhydrous ethanol and deionized water three times in sequence, and dry at 64 °C to constant weight to obtain epoxidized sepiolite; ultrasonically disperse the epoxidized sepiolite and anhydrous DMF, control the ultrasonic frequency at 25 kHz, ultrasonic power at 400 w, ultrasonic for 14 min, at a rotation speed of 600 rpm, while stirring, dropwise add the mixed solution c of tetrabutylammonium bromide, carboxyl monomer, and anhydrous DMF, control to finish dropping in 12 min. After dropping, heat up to 108 °C, maintain the rotation speed unchanged, stir for 2.6 h. After the reaction, centrifuge, wash the precipitate with a 32% ethanol solution by mass three times, and dry at 60 °C to constant weight to obtain the modifier. Among them, the mass ratio of sepiolite, hydrochloric acid aqueous solution, and KH-560 is 3.4:26:0.6, the mass ratio of epoxidized sepiolite, anhydrous DMF, and mixed solution c is 4:56:12, in the mixed solution c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer, and anhydrous DMF is 0.2:1.0:16, and the mass fraction of the hydrochloric acid aqueous solution is 12%.

[0023] Preparation Examples 4-6 and Comparative Preparation Examples 3-5 provide a functional filler.

[0024] Preparation Example 4 This preparation example provides a functional filler, which is prepared by the following steps: Step B1: Grind the waste tire to pass through a 30-mesh sieve, then soak it in an aqueous sodium hydroxide solution for 24 h, wash it with deionized water until neutral, and dry it to constant weight at 55 °C to obtain alkali-treated rubber powder; Stir the alkali-treated rubber powder and the aqueous hydrogen peroxide solution at a speed of 720 rpm for 18 min until homogeneous, adjust the pH to 4.2 with a 16% hydrochloric acid aqueous solution, raise the temperature to 46 °C, stir and react for 5.4 h, filter while it is hot, wash the filter cake with absolute ethanol and deionized water 3 times each, and dry it to constant weight at 62 °C to obtain modified rubber powder; Among them, the mass ratio of the waste tire powder to the aqueous sodium hydroxide solution is 12:80, the mass fraction of the aqueous sodium hydroxide solution is 18%, the mass ratio of the alkali-treated rubber powder to the aqueous hydrogen peroxide solution is 8:160, and the mass fraction of the aqueous hydrogen peroxide solution is 3%; Step B2: Ultrasonically disperse the modified rubber powder and the modifier prepared in Preparation Example 1 in anhydrous DMF, control the ultrasonic frequency at 25 kHz, the ultrasonic power at 350 w, ultrasonic for 16 min, raise the temperature to 56 °C, stir at a speed of 520 rpm for 10 h, control the rotary evaporation temperature at 83 °C, rotary evaporate until anhydrous DMF is removed, then wash it 3 times with an 18% ethanol aqueous solution, and dry it to constant weight at 66 °C to obtain the functional filler; Among them, the mass ratio of the modified rubber powder, the modifier and anhydrous DMF is 2:6.5:66.

[0025] Preparation Example 5 This preparation example provides a functional filler, which is prepared by the following steps: Step B1: Grind the waste tire to pass through a 40-mesh sieve, then soak it in an aqueous sodium hydroxide solution for 24 h, wash it with deionized water until neutral, and dry it to constant weight at 60 °C to obtain alkali-treated rubber powder; Stir the alkali-treated rubber powder and the aqueous hydrogen peroxide solution at a speed of 760 rpm for 20 min until homogeneous, adjust the pH to 4.8 with an 18% hydrochloric acid aqueous solution, raise the temperature to 50 °C, stir and react for 5.8 h, filter while it is hot, wash the filter cake with absolute ethanol and deionized water 4 times each, and dry it to constant weight at 66 °C to obtain modified rubber powder; Among them, the mass ratio of the waste tire powder to the aqueous sodium hydroxide solution is 12:100, the mass fraction of the aqueous sodium hydroxide solution is 20%, the mass ratio of the alkali-treated rubber powder to the aqueous hydrogen peroxide solution is 8:170, and the mass fraction of the aqueous hydrogen peroxide solution is 4%; Step B2: Ultrasonically disperse the modified rubber powder and the modifier prepared in Preparation Example 2 in anhydrous DMF. Control the ultrasonic frequency at 30 kHz, the ultrasonic power at 450 w, and ultrasonic for 18 min. Then raise the temperature to 59 °C and stir for 12 h at a rotation speed of 540 rpm. Control the rotary evaporation temperature at 85 °C and rotary evaporate until anhydrous DMF is removed. Then wash with an aqueous ethanol solution with a mass fraction of 22% four times and dry at 72 °C to constant weight to obtain the functional filler. Among them, the mass ratio of the modified rubber powder, the modifier, and anhydrous DMF is 2:7.1:70.

[0026] Preparation Example 6 This preparation example provides a functional filler, which is prepared by the following steps: Step B1: Grind the waste tire powder to pass through a 50-mesh sieve, then add it to an aqueous sodium hydroxide solution and soak for 24 h. Wash with deionized water until neutral, and dry at 65 °C to constant weight to obtain the alkali-treated rubber powder. Stir the alkali-treated rubber powder and the aqueous hydrogen peroxide solution evenly at a rotation speed of 800 rpm for 20 min. Adjust the pH to 5.6 with a 20% hydrochloric acid aqueous solution, raise the temperature to 54 °C, and stir and react for 6.2 h. Filter while it is hot. Wash the filter cake with anhydrous ethanol and deionized water five times each, and dry at 70 °C to constant weight to obtain the modified rubber powder. Among them, the mass ratio of the waste tire powder to the aqueous sodium hydroxide solution is 12:120, the mass fraction of the aqueous sodium hydroxide solution is 22%, the mass ratio of the alkali-treated rubber powder to the aqueous hydrogen peroxide solution is 8:180, and the mass fraction of the aqueous hydrogen peroxide solution is 5%; Step B2: Ultrasonically disperse the modified rubber powder and the modifier prepared in Preparation Example 3 in anhydrous DMF. Control the ultrasonic frequency at 25 kHz, the ultrasonic power at 400 w, and ultrasonic for 20 min. Then raise the temperature to 62 °C and stir for 14 h at a rotation speed of 560 rpm. Control the rotary evaporation temperature at 87 °C and rotary evaporate until anhydrous DMF is removed. Then wash with an aqueous ethanol solution with a mass fraction of 26% five times and dry at 76 °C to constant weight to obtain the functional filler. Among them, the mass ratio of the modified rubber powder, the modifier, and anhydrous DMF is 4:8.7:74.

[0027] Comparative Preparation Example 3 This preparation example provides a functional filler, which is prepared by the following steps: Step B1: Grind the waste tire to pass through a 30-mesh sieve, then soak it in an aqueous sodium hydroxide solution for 24 h, wash it with deionized water until neutral, dry it to constant weight at 55 °C to obtain alkali-treated rubber powder; Stir the alkali-treated rubber powder and aqueous hydrogen peroxide solution at a rotation speed of 720 rpm for 18 min until homogeneous, adjust the pH to 4.2 with a 16% hydrochloric acid aqueous solution, raise the temperature to 46 °C, stir and react for 5.4 h, filter while it is hot, wash the filter cake with anhydrous ethanol and deionized water 3 times each, and dry it to constant weight at 62 °C to obtain modified rubber powder; Among them, the mass ratio of waste tire powder to aqueous sodium hydroxide solution is 12:80, the mass fraction of the aqueous sodium hydroxide solution is 18%, the mass ratio of alkali-treated rubber powder to aqueous hydrogen peroxide solution is 8:160, and the mass fraction of the aqueous hydrogen peroxide solution is 3%; Step B2: Ultrasonically disperse the modified rubber powder and the modifier prepared in Comparative Preparation Example 1 in anhydrous DMF, control the ultrasonic frequency at 25 kHz, the ultrasonic power at 350 w, ultrasonic for 16 min, raise the temperature to 56 °C, stir at a rotation speed of 520 rpm for 10 h, control the rotary evaporation temperature at 83 °C, rotary evaporate until anhydrous DMF is removed, then wash it 3 times with an 18% ethanol aqueous solution, and dry it to constant weight at 66 °C to obtain the functional filler, where the mass ratio of modified rubber powder, modifier and anhydrous DMF is 2:6.5:66.

[0028] Comparative Preparation Example 4 This comparative preparation example provides a functional filler, which is prepared by the following steps: Step B1: Grind the waste tire to pass through a 30-mesh sieve, then soak it in an aqueous sodium hydroxide solution for 24 h, wash it with deionized water until neutral, dry it to constant weight at 55 °C to obtain alkali-treated rubber powder; Stir the alkali-treated rubber powder and aqueous hydrogen peroxide solution at a rotation speed of 720 rpm for 18 min until homogeneous, adjust the pH to 4.2 with a 16% hydrochloric acid aqueous solution, raise the temperature to 46 °C, stir and react for 5.4 h, filter while it is hot, wash the filter cake with anhydrous ethanol and deionized water 3 times each, and dry it to constant weight at 62 °C to obtain modified rubber powder; Among them, the mass ratio of waste tire powder to aqueous sodium hydroxide solution is 12:80, the mass fraction of the aqueous sodium hydroxide solution is 18%, the mass ratio of alkali-treated rubber powder to aqueous hydrogen peroxide solution is 8:160, and the mass fraction of the aqueous hydrogen peroxide solution is 3%; Step B2: Ultrasonically disperse the modified rubber powder and the modifier prepared in Comparative Preparation Example 2 in anhydrous DMF. Control the ultrasonic frequency at 25 kHz, the ultrasonic power at 350 w, ultrasonic for 16 min, heat up to 56 °C, stir at a rotation speed of 520 rpm for 10 h, control the rotary evaporation temperature at 83 °C, rotary evaporate until anhydrous DMF is removed, then wash with an ethanol aqueous solution with a mass fraction of 18% three times, and dry at 66 °C to constant weight to obtain the functional filler. Among them, the mass ratio of the modified rubber powder, the modifier and anhydrous DMF is 2:6.5:66.

[0029] Comparative Preparation Example 5 This Comparative Preparation Example provides a functional filler, which is prepared by the following steps: Step B1: Grind the waste tire powder to pass through a 30-mesh sieve, then add it to an aqueous sodium hydroxide solution and soak for 24 h, wash with deionized water until neutral, and dry at 55 °C to constant weight to obtain the alkali-treated rubber powder; Stir the alkali-treated rubber powder and deionized water at a rotation speed of 720 rpm for 18 min until uniform, adjust the pH to 4.2 with a hydrochloric acid aqueous solution with a mass fraction of 16%, heat up to 46 °C, stir and react for 5.4 h, filter while it is hot, wash the filter cake with anhydrous ethanol and deionized water three times each, and dry at 62 °C to constant weight to obtain the modified rubber powder; Among them, the mass ratio of the waste tire powder and the aqueous sodium hydroxide solution is 12:80, the mass fraction of the aqueous sodium hydroxide solution is 18%, and the mass ratio of the alkali-treated rubber powder and deionized water is 8:160; Step B2: Ultrasonically disperse the modified rubber powder and the modifier prepared in Preparation Example 1 in anhydrous DMF. Control the ultrasonic frequency at 25 kHz, the ultrasonic power at 350 w, ultrasonic for 16 min, heat up to 56 °C, stir at a rotation speed of 520 rpm for 10 h, control the rotary evaporation temperature at 83 °C, rotary evaporate until anhydrous DMF is removed, then wash with an ethanol aqueous solution with a mass fraction of 18% three times, and dry at 66 °C to constant weight to obtain the functional filler. Among them, the mass ratio of the modified rubber powder, the modifier and anhydrous DMF is 2:6.5:66.

[0030] Preparation Examples 7-9 and Comparative Preparation Example 6 provide a modified epoxy prepolymer.

[0031] Preparation Example 7 This Preparation Example provides a modified epoxy prepolymer, which is prepared by the following steps: Step A1: Stir deionized water, absolute ethanol and octylphenol polyoxyethylene ether at 720 rpm for 16 min until uniform. Add lignin, stir and mix for 12 min, adjust the pH to 3 with a 18% hydrochloric acid aqueous solution, dropwise add KH-560, control the dropping within 30 min. After dropping, raise the temperature to 46 °C, maintain the rotation speed unchanged, continue to stir and react for 12 h, centrifuge, wash the precipitate with absolute ethanol and deionized water 3 times successively, and dry at 60 °C to constant weight to obtain epoxy lignin. Among them, the mass ratio of deionized water, absolute ethanol, octylphenol polyoxyethylene ether, lignin and KH-560 is 32:90:1.2:8:0.8; Step A2: Ultrasonically disperse epoxy lignin and anhydrous DMF, control the ultrasonic frequency at 30 kHz, ultrasonic power at 450 w, ultrasonic for 16 min, control the rotation speed at 600 rpm, and dropwise add a mixed solution a of trifluoromethanesulfonic acid, diallylamine and anhydrous DMF while stirring. After the dropping is completed, raise the temperature to 78 °C, maintain the rotation speed unchanged, continue to stir for 2 h. After the reaction is completed, centrifuge, wash the precipitate with a 26% ethanol aqueous solution 3 times, and dry at 62 °C to constant weight to obtain modified lignin. Among them, the mass ratio of epoxy lignin, anhydrous DMF and the mixed solution a is 3.6:72:26. In the mixed solution a, the mass ratio of trifluoromethanesulfonic acid, diallylamine and anhydrous DMF is 0.4:1.0:24; Step A3: Add the modified lignin into deionized water, adjust the pH to 10 with a 20% sodium hydroxide aqueous solution, stir at 730 rpm for 11 min until uniform, then add epichlorohydrin and cetyltrimethylammonium bromide, raise the temperature to 58 °C, maintain the rotation speed unchanged, continue to stir and react for 3.2 h. After the reaction is completed, precipitate, and dry at 70 °C to constant weight to obtain a modified epoxy prepolymer. Among them, the mass ratio of the modified lignin, deionized water, epichlorohydrin and cetyltrimethylammonium bromide is 3.5:60:42:0.42.

[0032] Preparation Example 8 This preparation example provides a modified epoxy prepolymer, which is prepared by the following steps: Step A1: Stir deionized water, absolute ethanol and octylphenol polyoxyethylene ether at 760 rpm for 22 min until uniform. Add lignin, stir and mix for 15 min, adjust the pH to 3.5 with a 22% hydrochloric acid aqueous solution, dropwise add KH-560, control the dropping within 30 min. After dropping, raise the temperature to 50 °C, maintain the rotation speed unchanged, continue to stir and react for 18 h, centrifuge, wash the precipitate with absolute ethanol and deionized water 4 times successively, and dry at 65 °C to constant weight to obtain epoxy lignin. Among them, the mass ratio of deionized water, absolute ethanol, octylphenol polyoxyethylene ether, lignin and KH-560 is 39:95:1.4:8:1.0; Step A2: Ultrasonically disperse epoxy lignin and anhydrous DMF, control the ultrasonic frequency at 35 kHz, the ultrasonic power at 500 w, and ultrasonicate for 18 min. While stirring at a rotation speed of 640 rpm, dropwise add the mixed solution a of trifluoromethanesulfonic acid, diallylamine, and anhydrous DMF. After the addition is complete, raise the temperature to 81 °C and stir for 2.5 h. After the reaction is complete, centrifuge, wash the precipitate 4 times with an ethanol aqueous solution with a mass fraction of 28%, and dry to a constant weight at 66 °C to obtain modified lignin. Among them, the mass ratio of epoxy lignin, anhydrous DMF, and the mixed solution a is 4.0:79:29. In the mixed solution a, the mass ratio of trifluoromethanesulfonic acid, diallylamine, and anhydrous DMF is 0.5:1.2:27; Step A3: Add the modified lignin to deionized water, adjust the pH to 10.5 with a sodium hydroxide aqueous solution with a mass fraction of 23%, stir at a rotation speed of 760 rpm for 14 min until homogeneous, then add epichlorohydrin and cetyltrimethylammonium bromide, raise the temperature to 61 °C, maintain the rotation speed unchanged, and continue to stir and react for 3.8 h. After the reaction is complete, precipitate and dry to a constant weight at 72 °C to obtain a modified epoxy prepolymer. Among them, the mass ratio of the modified lignin, deionized water, epichlorohydrin, and cetyltrimethylammonium bromide is 3.5:65:44:0.48.

[0033] Preparation Example 9 This preparation example provides a modified epoxy prepolymer, which is prepared by the following steps: Step A1: Stir deionized water, anhydrous ethanol, and octylphenol polyoxyethylene ether at a rotation speed of 800 rpm for 28 min until homogeneous, add lignin, stir and mix for 18 min, adjust the pH to 4 with a hydrochloric acid aqueous solution with a mass fraction of 26%, dropwise add KH-560, control the dropping to be completed within 30 min. After dropping, raise the temperature to 54 °C, maintain the rotation speed unchanged, and continue to stir and react for 124 h. Centrifuge, and wash the precipitate successively 5 times with anhydrous ethanol and deionized water, and dry to a constant weight at 70 °C to obtain epoxy lignin. Among them, the mass ratio of deionized water, anhydrous ethanol, octylphenol polyoxyethylene ether, lignin, and KH-560 is 46:100:1.6:8:1.2; Step A2: Ultrasonically disperse epoxy lignin and anhydrous DMF, control the ultrasonic frequency at 25 kHz, the ultrasonic power at 400 W, and sonicate for 22 min. While stirring at a rotation speed of 700 rpm, dropwise add the mixed solution a of trifluoromethanesulfonic acid, diallylamine, and anhydrous DMF. After the addition is completed, raise the temperature to 110 °C and stir for 3 h. After the reaction is completed, centrifuge. Wash the precipitate 5 times with an aqueous ethanol solution with a mass fraction of 30%, and dry it at 70 °C to constant weight to obtain modified lignin. Among them, the mass ratio of epoxy lignin, anhydrous DMF, and the mixed solution a is 4.4:86:32. In the mixed solution a, the mass ratio of trifluoromethanesulfonic acid, diallylamine, and anhydrous DMF is 0.6:1.4:30. Step A3: Add the modified lignin to deionized water, adjust the pH to 11 with an aqueous sodium hydroxide solution with a mass fraction of 26%, stir at a rotation speed of 790 rpm for 17 min until homogeneous, then add epichlorohydrin and cetyltrimethylammonium bromide, raise the temperature to 64 °C, maintain the rotation speed unchanged, and continue stirring and reacting for 4.4 h. After the reaction is completed, precipitate, and dry it at 74 °C to constant weight to obtain a modified epoxy prepolymer. Among them, the mass ratio of the modified lignin, deionized water, epichlorohydrin, and cetyltrimethylammonium bromide is 3.5:70:46:0.56.

[0034] Comparative Preparation Example 6 This comparative preparation example provides a modified epoxy prepolymer, which is prepared by the following steps: Step A1: Stir deionized water, anhydrous ethanol, and octylphenol polyoxyethylene ether at a rotation speed of 720 rpm for 16 min until homogeneous, add lignin, stir and mix for 12 min, adjust the pH to 3 with an aqueous hydrochloric acid solution with a mass fraction of 18%, dropwise add KH-560, control the dropping to be completed within 30 min. After the dropping is completed, raise the temperature to 46 °C, maintain the rotation speed unchanged, and continue stirring and reacting for 12 h. Centrifuge, and wash the precipitate successively with anhydrous ethanol and deionized water 3 times, and dry it at 60 °C to constant weight to obtain epoxy lignin. Among them, the mass ratio of deionized water, anhydrous ethanol, octylphenol polyoxyethylene ether, lignin, and KH-560 is 32:90:1.2:8:0.8; Step A2: Ultrasonically disperse epoxy lignin and anhydrous DMF, control the ultrasonic frequency at 30 kHz, ultrasonic power at 450 w, ultrasonic for 16 min, control the rotation speed at 600 rpm, and while stirring, dropwise add the mixed solution a of trifluoromethanesulfonic acid, di-sec-butylamine and anhydrous DMF. After the addition is completed, raise the temperature to 78 °C, keep the rotation speed unchanged, and continue stirring for 2 h. After the reaction is completed, centrifuge, wash the precipitate 3 times with an aqueous ethanol solution with a mass fraction of 26%, and dry it to constant weight at 62 °C to obtain modified lignin. Among them, the mass ratio of epoxy lignin, anhydrous DMF and the mixed solution a is 3.6:72:26. In the mixed solution a, the mass ratio of trifluoromethanesulfonic acid, di-sec-butylamine and anhydrous DMF is 0.4:1.0:24; Step A3: Add the modified lignin into deionized water, adjust the pH to 10 with an aqueous sodium hydroxide solution with a mass fraction of 20%, stir at a rotation speed of 730 rpm for 11 min until uniform, then add epichlorohydrin and cetyltrimethylammonium bromide, raise the temperature to 58 °C, keep the rotation speed unchanged, and continue stirring and reacting for 3.2 h. After the reaction is completed, precipitate and dry it to constant weight at 70 °C to obtain a modified epoxy prepolymer. Among them, the mass ratio of the modified lignin, deionized water, epichlorohydrin and cetyltrimethylammonium bromide is 3.5:60:42:0.42.

[0035] Examples 1-3 and Comparative Examples 1-4 provide a lightweight and high-strength epoxy resin foam material and its preparation method.

[0036] Example 1 This example provides a lightweight and high-strength epoxy resin foam material, which includes the following raw materials in parts by weight: 94 parts of the modified epoxy prepolymer prepared in Preparation Example 7, 1.2 parts of azobisisobutyronitrile, 16 parts of dicyandiamide, 0.9 part of azodicarbonamide, 0.6 part of tris(2,4-di-tert-butylphenyl) phosphite and 6 parts of the functional filler prepared in Preparation Example 4; The preparation method of this lightweight and high-strength epoxy resin foam material includes the following steps: Stir the modified epoxy prepolymer, azobisisobutyronitrile and dicyandiamide at a rotation speed of 1200 rpm for 14 min until uniform, add azodicarbonamide, tris(2,4-di-tert-butylphenyl) phosphite and the functional filler, lower the rotation speed to 620 rpm, continue stirring for 16 min, raise the temperature to 76 °C, keep the rotation speed unchanged, stir and react for 1.8 h, then place it in a mixer at 100 °C for 9 min, raise the temperature to 137 °C, pre-cure for 110 min, and then raise the temperature to 178 °C and foam for 14 min to obtain a lightweight and high-strength epoxy resin foam material.

[0037] Example 2 This embodiment provides a lightweight and high-strength epoxy resin foam material, which comprises the following raw materials in parts by weight: 100 parts of the modified epoxy prepolymer prepared in Preparation Example 8, 1.4 parts of azodiisooctanenitrile, 17 parts of diaminodiphenylsulfone, 1.05 parts of 4,4'-oxybis(benzenesulfonyl hydrazide), 0.75 parts of bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and 8 parts of the functional filler prepared in Preparation Example 5; The preparation method of the lightweight and high-strength epoxy resin foam material comprises the following steps: Stir the modified epoxy prepolymer, azodiisooctanenitrile, and diaminodiphenylsulfone at a rotation speed of 1300 rpm for 16 min until uniform, add 4,4'-oxybis(benzenesulfonyl hydrazide), bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and the functional filler, reduce the rotation speed to 660 rpm, stir for 17 min, raise the temperature to 79 °C, maintain the rotation speed unchanged, stir and react for 2.1 h, then place it in a mixer at 105 °C for 11.5 min, raise the temperature to 140 °C, pre-cure for 120 min, then raise the temperature to 180 °C, and foam for 18 min to obtain the lightweight and high-strength epoxy resin foam material.

[0038] Example 3 This embodiment provides a lightweight and high-strength epoxy resin foam material, which comprises the following raw materials in parts by weight: 106 parts of the modified epoxy prepolymer prepared in Preparation Example 9, 1.6 parts of azodiisobutyronitrile, 18 parts of dicyandiamide, 1.2 parts of azodicarbonamide, 0.9 parts of dilauryl thiodipropionate, and 10 parts of the functional filler prepared in Preparation Example 6; The preparation method of the lightweight and high-strength epoxy resin foam material comprises the following steps: Stir the modified epoxy prepolymer, azodiisobutyronitrile, and dicyandiamide at a rotation speed of 1400 rpm for 18 min until uniform, add azodicarbonamide, dilauryl thiodipropionate, and the functional filler, reduce the rotation speed to 700 rpm, stir for 18 min, raise the temperature to 82 °C, maintain the rotation speed unchanged, stir and react for 2.4 h, then place it in a mixer at 110 °C for 14 min, raise the temperature to 143 °C, pre-cure for 130 min, then raise the temperature to 182 °C, and foam for 20 min to obtain the lightweight and high-strength epoxy resin foam material.

[0039] Comparative Example 1 This comparative example provides a lightweight and high-strength epoxy resin foam material, which comprises the following raw materials in parts by weight: 94 parts of the modified epoxy prepolymer prepared in Comparative Preparation Example 6, 1.2 parts of azodiisobutyronitrile, 16 parts of dicyandiamide, 0.9 parts of azodicarbonamide, 0.6 parts of tris(2,4-di-tert-butylphenyl) phosphite, and 6 parts of the functional filler prepared in Preparation Example 4; The preparation method of the lightweight and high-strength epoxy resin foam material comprises the following steps: The modified epoxy prepolymer, azobisisobutyronitrile, and dicyandiamide are stirred at 1200 rpm for 14 min until homogeneous. Then, azodicarbonamide, tris(2,4-di-tert-butylphenyl) phosphite, and functional filler are added. The rotation speed is reduced to 620 rpm, and stirring continues for 16 min. The temperature is raised to 76 °C, and stirring reaction is carried out for 1.8 h while maintaining the rotation speed unchanged. Then, it is kneaded at 100 °C for 9 min, the temperature is raised to 137 °C, and precuring is carried out for 110 min. Then, the temperature is raised to 178 °C, and foaming is carried out for 14 min to obtain a lightweight and high-strength epoxy resin foam material.

[0040] Comparative Example 2 This comparative example provides a lightweight and high-strength epoxy resin foam material, including the following raw materials in parts by weight: 94 parts of the modified epoxy prepolymer prepared in Preparation Example 7, 1.2 parts of azobisisobutyronitrile, 16 parts of dicyandiamide, 0.9 part of azodicarbonamide, 0.6 part of tris(2,4-di-tert-butylphenyl) phosphite, and 6 parts of the functional filler prepared in Comparative Preparation Example 3; The preparation method of this lightweight and high-strength epoxy resin foam material includes the following steps: The modified epoxy prepolymer, azobisisobutyronitrile, and dicyandiamide are stirred at 1200 rpm for 14 min until homogeneous. Then, azodicarbonamide, tris(2,4-di-tert-butylphenyl) phosphite, and functional filler are added. The rotation speed is reduced to 620 rpm, and stirring continues for 16 min. The temperature is raised to 76 °C, and stirring reaction is carried out for 1.8 h while maintaining the rotation speed unchanged. Then, it is kneaded at 100 °C for 9 min, the temperature is raised to 137 °C, and precuring is carried out for 110 min. Then, the temperature is raised to 178 °C, and foaming is carried out for 14 min to obtain a lightweight and high-strength epoxy resin foam material.

[0041] Comparative Example 3 This comparative example provides a lightweight and high-strength epoxy resin foam material, including the following raw materials in parts by weight: 94 parts of the modified epoxy prepolymer prepared in Preparation Example 7, 1.2 parts of azobisisobutyronitrile, 16 parts of dicyandiamide, 0.9 part of azodicarbonamide, 0.6 part of tris(2,4-di-tert-butylphenyl) phosphite, and 6 parts of the functional filler prepared in Comparative Preparation Example 4; The preparation method of this lightweight and high-strength epoxy resin foam material includes the following steps: The modified epoxy prepolymer, azobisisobutyronitrile, and dicyandiamide are stirred at 1200 rpm for 14 min until homogeneous. Then, azodicarbonamide, tris(2,4-di-tert-butylphenyl) phosphite, and functional filler are added. The rotation speed is reduced to 620 rpm, and stirring continues for 16 min. The temperature is raised to 76 °C, and stirring reaction is carried out for 1.8 h while maintaining the rotation speed unchanged. Then, it is kneaded at 100 °C for 9 min, the temperature is raised to 137 °C, and precuring is carried out for 110 min. Then, the temperature is raised to 178 °C, and foaming is carried out for 14 min to obtain a lightweight and high-strength epoxy resin foam material.

[0042] Comparative Example 4 This comparative example provides a lightweight and high-strength epoxy resin foam material, which includes the following raw materials in parts by weight: 94 parts of the modified epoxy prepolymer prepared in Preparation Example 7, 1.2 parts of azobisisobutyronitrile, 16 parts of dicyandiamide, 0.9 parts of azodicarbonamide, 0.6 parts of tris(2,4-di-tert-butylphenyl) phosphite, and 6 parts of the functional filler prepared in Comparative Preparation Example 5; The preparation method of the lightweight and high-strength epoxy resin foam material includes the following steps: Stir the modified epoxy prepolymer, azobisisobutyronitrile, and dicyandiamide at a speed of 1200 rpm for 14 min until uniform, add azodicarbonamide, tris(2,4-di-tert-butylphenyl) phosphite, and the functional filler, reduce the speed to 620 rpm, continue stirring for 16 min, heat up to 76 °C, maintain the speed unchanged, stir and react for 1.8 h, then place it in a mixer at 100 °C for 9 min, heat up to 137 °C, pre-cure for 110 min, and then heat up to 178 °C for foaming for 14 min to obtain the lightweight and high-strength epoxy resin foam material.

[0043] Performance Testing The following performance tests were respectively carried out on the epoxy resin foam materials prepared in Examples 1-3 and Comparative Examples 1-4; 1. Mechanical property testing: The tensile strength and elongation at break were determined according to the method of GB / T2567-2021, and the impact strength was determined according to the method of GB / T2571-2021. The specific test results are shown in Table 1; 2. Heat distortion temperature testing: It was determined according to the method provided in GB / T1634.2-2019. The specific test results are shown in Table 2; 3. Resistance to ultraviolet aging performance testing: The aging conditions were as follows: the ultraviolet intensity was 1500 uw / cm2, the aging temperature was 60 °C, and the aging time was 360 h. The tensile strength and impact strength of the composite material were tested. Based on the initial mechanical property strength being 100%, the retention rate of its mechanical properties was calculated. The specific test results are shown in Table 2; Table 1 Mechanical property testing of the epoxy resin foam materials in Examples 1-3 and Comparative Examples 1-4

[0044] As can be seen from Table 1, compared with Comparative Examples 1-4, the epoxy resin foam materials prepared in Examples 1-3 have higher tensile strength, elongation at break, and impact strength. Therefore, the epoxy resin foam materials prepared by the present invention have more excellent mechanical properties.

[0045] Table 2 Heat resistance and ultraviolet resistance testing of the epoxy resin foam materials in Examples 1-3 and Comparative Examples 1-4

[0046] As can be seen from Table 2, compared with Comparative Examples 1-4, the epoxy resin foam materials prepared in Examples 1-3 have a higher heat distortion temperature, better ultraviolet resistance, elongation at break and impact strength. Therefore, the epoxy resin foam materials prepared in the present invention have more excellent heat resistance and ultraviolet aging resistance.

[0047] This specific embodiment is only an explanation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A lightweight and high-strength epoxy resin foam material, characterized in that: The invention comprises the following raw materials in parts by weight: 94-106 parts of modified epoxy prepolymer, 1.2-1.6 parts of initiator, 16-18 parts of curing agent, 0.9-1.2 parts of foaming agent, 0.6-0.9 parts of antioxidant and 6-10 parts of functional filler; The modified epoxy prepolymer is first prepared by modifying lignin with KH-560 to obtain epoxy lignin, which is then subjected to a ring-opening reaction with diallylamine to obtain modified lignin, and finally subjected to a nucleophilic substitution reaction with epichlorohydrin to obtain the modified lignin; The functional filler is firstly prepared by treating waste tire powder with a sodium hydroxide aqueous solution to obtain alkali-treated rubber powder, then oxidizing with a hydrogen peroxide aqueous solution to obtain modified rubber powder, and then coating and modifying with a modifier. The modifier is firstly prepared by an amidation reaction between 3-(chloromethyl)benzoic acid and 4,6-diaminopyrimidine to obtain a phenyl monomer, which is then reacted with p-hydroxycinnamic acid to obtain a carboxyl monomer through a nucleophilic substitution reaction, and then reacted with epoxy sepiolite through a ring-opening esterification reaction to obtain the modifier; The epoxy sepiolite is prepared by modifying sepiolite with KH-560.

2. A lightweight and high-strength epoxy resin foam material according to claim 1, characterized in that: The modified epoxy prepolymer is prepared by the following steps: Step A1, deionized water, anhydrous ethanol and octylphenol polyoxyethylene ether are mixed evenly, lignin is added, and the mixture is stirred for 12-18 minutes, the pH is adjusted to 3-4, KH-560 is added dropwise, and the dripping is controlled to be completed within 30 minutes. After the dripping is completed, the temperature is raised to 46-54° C., the mixture is stirred for reaction for 12-24 hours, centrifuged, the precipitate is washed and dried to obtain epoxy lignin; Step A2, ultrasonically dispersing epoxy lignin and anhydrous DMF, dripping a mixture of trifluoromethanesulfonic acid, diallylamine and anhydrous DMF, heating to 78-84°C and stirring for 2-3h after the reaction, centrifuging, washing and drying the precipitate to obtain modified lignin; Step A3, adding the modified lignin to deionized water, adjusting the pH to 10-11, stirring evenly, then adding epichlorohydrin and hexadecyltrimethylammonium bromide, heating to 58-64° C., stirring and reacting for 3.2-4.4 hours, after the reaction is completed, precipitating, and drying to obtain a modified epoxy prepolymer.

3. A lightweight and high-strength epoxy resin foam material according to claim 2, characterized in that: In the step A1, the mass ratio of deionized water, anhydrous ethanol, octylphenol polyoxyethylene ether, lignin and KH-560 is 32-46:90-100:1.2-1.6:8:0.8-1.

2.

4. A lightweight and high-strength epoxy resin foam material according to claim 2, characterized in that: In the step A2, the mass ratio of epoxy lignin, anhydrous DMF and mixed solution a is 3.6-4.4:72-86:26-32, and in the mixed solution a, the mass ratio of trifluoromethanesulfonic acid, diallylamine and anhydrous DMF is 0.4-0.6:1.0-1.4:24-30.

5. A lightweight and high-strength epoxy resin foam material according to claim 2, characterized in that: In the step A3, the mass ratio of modified lignin, deionized water, epichlorohydrin and hexadecyltrimethylammonium bromide is 3.5:60-70:42-46:0.42-0.

56.

6. A lightweight and high-strength epoxy resin foam material according to claim 1, characterized in that: The functional filler is prepared by the following steps: Step B1, grinding the waste tire powder to pass through a 30-50 mesh sieve, then adding it to a sodium hydroxide aqueous solution and soaking it for 24 hours, washing it to neutrality, and drying it to obtain alkali-treated rubber powder; mixing the alkali-treated rubber powder and the hydrogen peroxide aqueous solution uniformly, adjusting the pH to 4.2-5.6, heating it to 46-54° C., stirring and reacting it for 5.4-6.2 hours, filtering it while hot, washing the filter cake, and drying it to obtain modified rubber powder; Step B2, ultrasonically disperse the modified rubber powder and the modifier in anhydrous DMF, heat to 56-62° C., stir for 10-14 h, rotary evaporate, wash, and dry to obtain a functional filler.

7. A lightweight and high-strength epoxy resin foam material according to claim 6, characterized in that: In the step B1, the mass ratio of waste tire powder to sodium hydroxide aqueous solution is 12:80-120, the mass fraction of sodium hydroxide aqueous solution is 18-22%, the mass ratio of alkali-treated rubber powder to hydrogen peroxide aqueous solution is 8:160-180, the mass fraction of hydrogen peroxide aqueous solution is 3-5%, and in the step B2, the mass ratio of modified rubber powder, modifier and anhydrous DMF is 2-4:6.5-8.7:66-74.

8. The lightweight and high-strength epoxy resin foam material according to claim 1, characterized in that: The modifying agent is prepared by the following steps: Step C1, adding 3-(chloromethyl)benzoic acid to anhydrous ethanol, heating to 40-46° C., stirring evenly, then adding a mixed solution b of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and anhydrous ethanol, controlling the dripping to be completed within 15 minutes, heating to reflux, stirring to react for 4-6 hours, and after the reaction is completed, centrifuging, washing the precipitate, and drying to obtain a phenyl monomer; Step C2, adding phenyl monomer, p-hydroxycinnamic acid, triethylamine and toluene to anhydrous DMF, stirring evenly, heating to reflux under nitrogen protection, stirring and reacting for 5-8 hours, filtering after the reaction, rotary evaporating the filtrate, dissolving the rotary evaporation product in acetone, filtering, rotary evaporating the filtrate, washing, and drying to obtain a carboxyl monomer; Step C3, adding sepiolite to a hydrochloric acid aqueous solution, heating to 42-46°C, stirring evenly, adding KH-560, heating to 54-62°C, stirring for reaction for 4.6-5.8h, centrifuging, washing and drying the precipitate to obtain epoxidized sepiolite; ultrasonically dispersing the epoxidized sepiolite and anhydrous DMF, dripping a mixture of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF c, controlling the dripping time to be 12min, heating to 108-112°C, stirring for 2.6-3.4h, centrifuging after the reaction, washing and drying the precipitate to obtain a modifier.

9. A lightweight and high-strength epoxy resin foam material according to claim 8, characterized in that: In the step C1, the mass ratio of 3-(chloromethyl)benzoic acid, anhydrous ethanol and mixed solution b is 3-5:64-72:32-40, in the mixed solution b, the mass ratio of N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine, 4,6-diaminopyrimidine and anhydrous ethanol is 4.1-6.9:2.2-3.6:1.6-3.2:40-46, and in the step C2, the mass ratio of phenyl monomer, p-hydroxycinnamic acid, triethylamine, toluene, anhydrous DMF and acetone is 2.6-4.4:1.6 -2.8:0.2-0.4:26-34:86-92:20-24, in step C3, the mass ratio of sepiolite, aqueous hydrochloric acid solution and KH-560 is 3.4-4.4:26-32:0.6-0.8, the mass ratio of epoxidized sepiolite, anhydrous DMF and mixed solution c is 4:56-62:12, in the mixed solution c, the mass ratio of tetrabutylammonium bromide, carboxyl monomer and anhydrous DMF is 0.2:1.0-1.4:16-20, and the mass fraction of aqueous hydrochloric acid solution is 12-16%.

10. A method for preparing a lightweight and high-strength epoxy resin foam material according to any one of claims 1 to 9, characterized in that: The following steps are involved: Mix the modified epoxy prepolymer and curing agent evenly, add foaming agent, antioxidant and functional filler, stir for 16-18 minutes, heat to 76-82°C, stir and react for 1.8-2.4 hours, then place at 100-110°C for 9-14 minutes, heat to 137-143°C, pre-cure for 110-130 minutes, then heat to 178-182°C, foam for 14-20 minutes to obtain a lightweight and high-strength epoxy resin foam material.

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