CN-121991403-A - Preparation method of three-dimensional porous EP/MWCNT shape memory composite material

CN121991403ACN 121991403 ACN121991403 ACN 121991403ACN-121991403-A

Abstract

The invention discloses a preparation method of a three-dimensional porous EP/MWCNT shape memory composite material, which relates to the technical field of composite material preparation, and specifically comprises the steps of firstly adding a multiwall carbon nanotube into N, N-dimethylformamide according to the proportion of 2wt% to obtain a dispersion liquid by ultrasonic dispersion; adding epoxy resin into the mixture, heating and stirring the mixture to obtain a mixed system, then sequentially adding isocyanoethyl methacrylate and polyethylene glycol diacrylate for crosslinking reaction to obtain a precursor solution, then defoaming and injecting the precursor solution into a mould for freezing and forming, finally freeze-drying the precursor solution to remove the solvent to obtain the three-dimensional porous EP/MWCNT shape memory composite material.

Inventors

LI GANG
WU ZHAOLONG
SONG DA
GUO JIAQI

Assignees

东北电力大学

Dates

Publication Date: 20260508
Application Date: 20260306

Claims (10)

1. A preparation method of a three-dimensional porous EP/MWCNT shape memory composite material is characterized by comprising the following specific steps: s1, filler dispersion, namely adding multi-wall carbon nano tubes into N, N-dimethylformamide according to the mass fraction of 2wt%, and performing ultrasonic dispersion to obtain multi-wall carbon nano tube dispersion liquid; S2, matrix fusion, namely adding epoxy resin into the multiwall carbon nanotube dispersion liquid, and stirring and mixing under the heating condition to obtain an epoxy resin/multiwall carbon nanotube mixed system; S3, crosslinking reaction, namely adding isocyanoethyl methacrylate into the epoxy resin/multiwall carbon nanotube mixed system to perform pre-reaction, adding polyethylene glycol diacrylate, and heating to continue crosslinking reaction to obtain a precursor solution; s4, freezing and forming, namely, injecting the precursor solution into a mould after defoaming, and performing freezing treatment to form the precursor solution; S5, freeze-drying and shaping, namely freeze-drying the frozen and shaped sample, and removing the solvent to obtain the three-dimensional porous EP/MWCNT shape memory composite material.
2. The method for preparing the three-dimensional porous EP/MWCNT shape memory composite material according to claim 1, wherein in the step S1, the multi-walled carbon nanotube is a hydroxyl modified multi-walled carbon nanotube, the modification degree is 0.8-1.2mmol/g, the pipe diameter is 10-20nm, the length is 5-10 μm, the amorphous carbon content is less than or equal to 0.5%, the ash content is less than or equal to 0.3%, the ultrasonic dispersion power is 150-200W, the frequency is 40kHz, and the time is 1h.
3. The preparation method of the three-dimensional porous EP/MWCNT shape memory composite material is characterized in that in the step S1, N-dimethylformamide is chromatographic grade which is dehydrated by a 4A molecular sieve for more than 72 hours, the moisture content is less than or equal to 0.05%, the ultrasonic dispersion adopts a numerical control ultrasonic cell pulverizer, the ultrasonic mode is pulse ultrasonic, the pulse on-off ratio is 3S to 1S, and the ultrasonic power is fixed to be 180W.
4. The method for preparing the three-dimensional porous EP/MWCNT shape memory composite material according to claim 1, wherein in the step S2, the epoxy resin is bisphenol A type epoxy resin, the epoxy value is 0.51-0.54eq/100g, the viscosity at 25 ℃ is 11000-14000 mPa.s, the acid value is less than or equal to 0.03mgKOH/g, the volatile component is less than or equal to 0.1%, the epoxy resin and the multi-wall carbon nano tube dispersion are mixed according to the mass ratio of 1:1, the mixing temperature is 60+/-2 ℃, and the stirring time is 2h.
5. The preparation method of the three-dimensional porous EP/MWCNT shape memory composite material is characterized in that in the step S2, epoxy resin is slowly dripped into the multi-wall carbon nano tube dispersion liquid at a rate of 5mL/min, a constant-current peristaltic pump is adopted during dripping, a liquid outlet pipe is inserted below the liquid level, a variable-frequency mechanical stirrer is adopted for stirring, and the stirring rate is regulated in a gradient mode of 300r/min for 30min, 400r/min for 90min and 500r/min for 60 min.
6. The preparation method of the three-dimensional porous EP/MWCNT shape memory composite material according to claim 1, wherein in the step S3, the addition amount of the isocyanoethyl methacrylate is 15% of the mass of the epoxy resin, the purity is more than or equal to 99.0%, the isocyanate group content is 3.8-4.2mmol/g, and the mass ratio of the polyethylene glycol diacrylate to the epoxy resin is 1:10.
7. The method for preparing the three-dimensional porous EP/MWCNT shape memory composite material according to claim 1, wherein in the step S3, the pre-reaction is carried out for 1h at 60 ℃, after polyethylene glycol diacrylate is added, the temperature of the system is raised to 65+/-2 ℃ at the heating rate of 1 ℃ per minute, the reaction is continued for 4h at the stirring rate of 400r/min, the gel content is sampled and detected every 30min, the reaction is stopped when the gel content reaches 92% -95%, the gel content is detected by adopting a Soxhlet extraction method, the extraction solvent is acetone, and the extraction time is 24h.
8. The method for preparing the three-dimensional porous EP/MWCNT shape memory composite material according to claim 1, wherein in the step S4, the precursor solution is defoamed in a vacuum box with the vacuum degree of less than or equal to 5Pa for 30min, then the precursor solution is injected into a polytetrafluoroethylene mould, the injection amount is 95% of the volume of the mould, the roughness Ra of the inner wall surface of the mould is less than or equal to 0.05 mu m, the mould is cleaned and dried, and then the mould is placed in an ultralow temperature freezer with the temperature of minus 40+/-3 ℃ and frozen for 12h in a gradient cooling mode.
9. The method for preparing the three-dimensional porous EP/MWCNT shape memory composite material according to claim 8, wherein in the step S4, the gradient cooling process is that the temperature is reduced to 0 ℃ from room temperature at a rate of 5 ℃ per minute, the temperature is kept for 1h, the temperature is reduced to-40 ℃ at a rate of 2 ℃ per minute, the vacuum degree is gradually reduced to less than or equal to 5Pa from normal pressure during the deaeration, the depressurization rate is 1Pa/S, and the vacuum box is gently rocked every 10min during the deaeration.
10. The method for preparing the three-dimensional porous EP/MWCNT shape memory composite material according to claim 1, wherein in the step S5, the frozen and molded samples are put into a freeze dryer together, the cold trap temperature is set to be less than or equal to 50 ℃, freeze drying is carried out in three stages, wherein the vacuum degree in the first stage is controlled to be 8Pa, the vacuum degree in the second stage is controlled to be 3Pa, the tray temperature is increased to be 25 ℃ in the third stage under the vacuum degree of 3Pa, the total drying time is 48 hours, the drying is judged to be finished until the mass change rate of the samples is less than or equal to 0.1% for 4 hours continuously, then the samples are taken out after the vacuum is slowly broken, and dry nitrogen is introduced when the vacuum is broken.

Description

Preparation method of three-dimensional porous EP/MWCNT shape memory composite material Technical Field The invention relates to the technical field of composite material preparation, in particular to a preparation method of a three-dimensional porous EP/MWCNT shape memory composite material. Background The shape memory composite material has both shape memory effect and excellent mechanical property of the composite material, so that the shape memory composite material becomes one of research hot spots in the field of intelligent materials, the epoxy resin-based shape memory composite material has wide application prospect in various fields such as aerospace, intelligent equipment, biomedical and the like by virtue of good formability, chemical stability and excellent shape memory recovery property, the carbon nano tube and other nano fillers are introduced to further improve the comprehensive performance of the epoxy resin-based shape memory composite material, the carbon nano tube can effectively improve the functional characteristics and mechanical property of an epoxy resin matrix by virtue of a unique one-dimensional nano structure and excellent electric conduction, heat conduction and mechanical property, and the three-dimensional porous structure is constructed to enable the material to have light weight advantage and good structural response, so that the preparation of the three-dimensional porous epoxy resin/multi-wall carbon nano tube shape memory composite material becomes an important research direction in the field, and the related preparation process is also focused. In the traditional preparation process of the epoxy resin/multi-wall carbon nanotube composite material, the carbon nanotubes are easy to agglomerate due to Van der Waals force, uniform dispersion is difficult to realize in an epoxy resin matrix, so that poor interface bonding performance of a filler and the matrix is caused, the modification effect of the carbon nanotubes cannot be fully exerted, the shape memory performance and mechanical performance of the composite material are further influenced, meanwhile, the traditional crosslinking reaction regulation and control mode is rough, the forming process of a crosslinked network is difficult to accurately control, the problem of insufficient crosslinking degree or excessive crosslinking is easy to occur, the shape memory recovery rate and the circulation stability of the material are reduced, in addition, the problem of uneven pore distribution and structural collapse are easy to occur in the traditional porous structure forming process, the microstructure of the material is easily damaged in the solvent removing process, and the practical application and the large-scale production of the material are restricted. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a preparation method of a three-dimensional porous EP/MWCNT shape memory composite material, which takes a hydroxyl modified multiwall carbon nanotube and bisphenol A type epoxy resin as core raw materials, and the target material is prepared through five steps of filler dispersion, matrix fusion, crosslinking reaction, freeze molding and freeze-drying shaping, wherein the carbon nanotube is uniformly dispersed through pulse ultrasound in the preparation process, the stable fusion of the matrix and the filler is ensured by gradient stirring, the gel content is regulated and controlled in steps to form a regular crosslinking network, and a gradient freezing and sectional freeze-drying process is combined, so that a uniform three-dimensional porous structure is reserved while a solvent is removed. The invention provides a preparation method of a three-dimensional porous EP/MWCNT shape memory composite material, which comprises the following specific steps of: s1, filler dispersion, namely adding multi-wall carbon nano tubes into N, N-dimethylformamide according to the mass fraction of 2wt%, and performing ultrasonic dispersion to obtain multi-wall carbon nano tube dispersion liquid; S2, matrix fusion, namely adding epoxy resin into the multiwall carbon nanotube dispersion liquid, and stirring and mixing under the heating condition to obtain an epoxy resin/multiwall carbon nanotube mixed system; S3, crosslinking reaction, namely adding isocyanoethyl methacrylate into the epoxy resin/multiwall carbon nanotube mixed system to perform pre-reaction, adding polyethylene glycol diacrylate, and heating to continue crosslinking reaction to obtain a precursor solution; s4, freezing and forming, namely, injecting the precursor solution into a mould after defoaming, and performing freezing treatment to form the precursor solution; S5, freeze-drying and shaping, namely freeze-drying the frozen and shaped sample, and removing the solvent to obtain the three-dimensional porous EP/MWCNT shape memory composite material. Further, the multi-wall carbon nano tube is a hydroxyl modified multi-wa