CN115058046A - CNT/EVA shape memory composite material and preparation method thereof - Google Patents
CNT/EVA shape memory composite material and preparation method thereof Download PDFInfo
- Publication number
- CN115058046A CN115058046A CN202210816421.6A CN202210816421A CN115058046A CN 115058046 A CN115058046 A CN 115058046A CN 202210816421 A CN202210816421 A CN 202210816421A CN 115058046 A CN115058046 A CN 115058046A
- Authority
- CN
- China
- Prior art keywords
- eva
- cnt
- shape memory
- composite material
- preparing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 78
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 206010042674 Swelling Diseases 0.000 claims abstract description 17
- 239000006185 dispersion Substances 0.000 claims abstract description 17
- 230000008961 swelling Effects 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 16
- 238000009210 therapy by ultrasound Methods 0.000 claims abstract description 15
- 239000007788 liquid Substances 0.000 claims abstract description 7
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000008096 xylene Substances 0.000 claims abstract description 6
- 238000001035 drying Methods 0.000 claims abstract description 4
- 238000004140 cleaning Methods 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 238000001125 extrusion Methods 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 7
- 239000004594 Masterbatch (MB) Substances 0.000 claims description 4
- 239000003431 cross linking reagent Substances 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 238000007731 hot pressing Methods 0.000 claims description 2
- 238000002525 ultrasonication Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- 239000002041 carbon nanotube Substances 0.000 abstract description 5
- 230000007334 memory performance Effects 0.000 abstract description 5
- 230000008569 process Effects 0.000 abstract description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 abstract description 2
- 239000012767 functional filler Substances 0.000 abstract description 2
- 239000012781 shape memory material Substances 0.000 abstract description 2
- 239000005038 ethylene vinyl acetate Substances 0.000 description 91
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 description 90
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 90
- 238000011084 recovery Methods 0.000 description 12
- 239000011159 matrix material Substances 0.000 description 11
- 238000012545 processing Methods 0.000 description 6
- 229920000431 shape-memory polymer Polymers 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 230000009471 action Effects 0.000 description 4
- 230000006399 behavior Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000000527 sonication Methods 0.000 description 4
- 238000002604 ultrasonography Methods 0.000 description 4
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical group CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 3
- 239000002346 layers by function Substances 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000001938 differential scanning calorimetry curve Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000001931 thermography Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical group CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 229910021392 nanocarbon Inorganic materials 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/12—Chemical modification
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/04—Homopolymers or copolymers of ethene
- C08J2323/08—Copolymers of ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/001—Conductive additives
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/011—Nanostructured additives
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/04—Carbon
- C08K3/041—Carbon nanotubes
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention belongs to the technical field of shape memory materials, and particularly relates to a CNT/EVA shape memory composite material and a preparation method thereof, wherein the CNT/EVA shape memory composite material comprises the following steps: (1) preparing CNT dispersion liquid and preparing an EVA film; (2) placing the EVA film in a xylene solution for swelling; (3) placing the EVA film subjected to swelling treatment in CNT dispersion liquid under an ice bath condition and carrying out ultrasonic treatment; and then taking out the film, cleaning and drying to prepare the CNT/EVA shape memory composite material. According to the invention, the cross-linked EVA and the conductive functional filler carbon nano tube are compounded through a swelling ultrasonic process to prepare the shape memory composite material with excellent electric and thermal driving shape memory performance and mechanical performance.
Description
Technical Field
The invention belongs to the technical field of shape memory materials, and particularly relates to a CNT/EVA shape memory composite material and a preparation method thereof.
Background
Shape Memory Polymer (SMP), a smart polymer material with a crystalline or semi-crystalline structure. The shape memory recovery principle is different, and the heat-driven type, the indirect heat-driven type such as the electric-driven type and the photo-induced type, and the chemical induction type are classified. The SMP has the advantages of large return strain, light weight, low price, easy processing and forming, wide application range and the like, and is widely applied to the fields of textile and clothing, biomedicine, aerospace, self-repairing materials and 3D/4D printing.
Although SMP has excellent shape memory performance, it has the disadvantages of small recovery stress, low recovery precision and speed, poor mechanical property, single-direction memory, single driving form and the like. Research on the composite material finds that the Shape Memory Polymer Composite (SMPC) prepared by compounding the SMP and fillers such as fibers, whiskers and particles can effectively improve the creep and stress relaxation behaviors and obviously improve the strength, modulus and recovery stress of the material.
Ethylene-vinyl acetate (EVA) is a semi-crystalline random copolymer prepared by copolymerization of a nonpolar ethylene monomer and a strongly polar vinyl acetate monomer (VAC) under the action of an initiator. Since the reactivity ratios of the two monomers are very similar, the pendant acetate groups on the EVA are completely undistributed. In addition, compared with shape memory polyethylene, the steric hindrance formed after the introduction of the polar VAC group on the molecular chain causes the original crystal structure to be destroyed, the molecular chain gap to be enlarged, and the melting point and the crystallinity of the system to be obviously reduced, therefore, the prepared EVA has higher flexibility and elasticity and simultaneously shows good processing performance. However, the direct thermal drive of pure EVA has disadvantages of low thermal efficiency, long response time, etc. In addition, for complex applications such as local/multi-stage control of complex structures and the like which are not suitable for direct heating, for example, remote control of actuators, the method for realizing shape recovery through direct thermal driving is very strict, and meanwhile, the defects that the heat quantity, the temperature rise speed and the precision of materials cannot be regulated and controlled exist.
Disclosure of Invention
Based on the above-mentioned disadvantages and shortcomings of the prior art, it is an object of the present invention to at least solve one or more of the above-mentioned problems of the prior art, in other words, to provide a CNT/EVA shape memory composite and a method for preparing the same that satisfy one or more of the above-mentioned needs.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a CNT/EVA shape memory composite material comprises the following steps:
(1) preparing CNT dispersion liquid and preparing an EVA film;
(2) placing the EVA film in a xylene solution for swelling;
(3) placing the EVA film subjected to swelling treatment in CNT dispersion liquid under an ice bath condition and carrying out ultrasonic treatment; and then taking out the film, cleaning and drying to prepare the CNT/EVA shape memory composite material.
Preferably, the step (1) of preparing the CNT dispersion includes:
the CNT powder was added to a solution containing DMF and water, followed by ultrasonication under ice bath conditions for at least 30min to obtain a CNT dispersion.
Preferably, the concentration of the CNT dispersion is 1-3 mg/mL.
Preferably, the volume ratio of DMF to water is (2-4): (8-6).
Preferably, in step (1), the preparation of the EVA film comprises:
premixing EVA master batch and a crosslinking agent DCP according to a target mass ratio, and then performing melt extrusion blending;
then placing the mixture particles subjected to melt extrusion into a mold, placing the mold in a flat vulcanizing machine for preheating, pressurizing to 10MPa, raising the temperature to 150 ℃, and carrying out hot pressing for 1h to obtain the EVA film.
Preferably, the target mass ratio is (95-98): (5-2).
Preferably, the heating zone temperatures of the screw extruder used for melt extrusion blending are set to 85 ℃, 90 ℃, 95 ℃ and 100 ℃.
Preferably, in the step (2), the swelling temperature is 35-45 ℃, and constant-temperature swelling is adopted.
Preferably, in the step (3), the duration of the ultrasonic treatment is 10-40 min.
The invention also provides the CNT/EVA shape memory composite material prepared by the preparation method of any one of the above schemes.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the cross-linked EVA and the conductive functional filler carbon nano tube are compounded through a swelling ultrasonic process to prepare the shape memory composite material with excellent electric and thermal driving shape memory performance and mechanical performance.
Drawings
FIG. 1 is an SEM image of each CNT/EVA shape memory composite of example 1 of the invention; (a)10min, (b)20min, (c)30min and (d)40 min; CNT/EVA 20 The surface appearance (e-g) and the section appearance (h-k) of the composite material film;
FIG. 2 is a graph comparing the mechanical properties of EVA and CNT/EVA shape memory composite of example 1 of the present invention;
FIG. 3 is a graph comparing the electrical conductivity of the CNT/EVA shape memory composite of example 1 of the invention;
FIG. 4 is a DSC curve of EVA and CNT/EVA shape memory composite of example 1 of the present invention;
FIG. 5 is a thermally driven shape memory recovery process of the CNT/EVA composite of example 1 of the invention;
FIG. 6 is a graph of electrothermal transition temperature versus time for the CNT/EVA composite of example 1 of the invention;
FIG. 7 is an infrared thermal imaging photograph of the surface temperature change of the CNT/EVA composite of example 1 of the invention at a voltage of 10V;
fig. 8 is a photograph of (a) an electrically driven recovery process and (b) an infrared thermal image of the CNT/EVA composite of example 1 of the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention, the following description will explain the embodiments of the present invention with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.
Example 1:
the preparation method of the CNT/EVA shape memory composite material comprises the following steps:
(1) preparation of CNT Dispersion
200mg of CNT powder was weighed and added to a solution containing 30mL of DMF and 70mL of deionized water; and then placing the prepared solution in an ice bath environment, and continuously carrying out ultrasonic treatment for 30min by using an ultrasonic cell crusher to realize uniform dispersion of the CNT in the mixed solution to obtain a CNT dispersion solution.
(2) Preparation of EVA film
Firstly, mixing EVA master batch and a crosslinking agent DCP in a ratio of 97: 3, then carrying out melt extrusion blending at a host machine screw rotating speed of 30rpm by using a miniature double-screw extruder (the temperature of a heating zone is respectively set to 85 ℃, 90 ℃, 95 ℃ and 100 ℃);
then, the melt-extruded mixture pellets were placed in a mold having a thickness of 0.35mm and placed in a press vulcanizer, preheated at 90 ℃ for 5min, then pressurized to 10MPa and hot-pressed at 150 ℃ for 1h to sufficiently crosslink EVA, thereby obtaining an EVA film.
(3) Preparation of CNT/EVA composite material film
Placing the EVA film in 100mL xylene solution at 40 ℃, swelling at constant temperature for 30min, and swelling due to diffusion and permeation of xylene molecules into the EVA, mixing of the xylene molecules with segments of the EVA macromolecules, so that the macromolecular gaps are increased, thereby expanding the volume of the EVA film;
and then, under the ice bath condition, placing the EVA film subjected to full swelling treatment in a CNT dispersion liquid, continuously carrying out ultrasonic treatment in an ultrasonic cell crusher for 10min, 20min, 30min and 40min, and finally taking out the CNT/EVA composite material film and alternately washing the CNT/EVA composite material film with deionized water and absolute ethyl alcohol to remove the CNT with poor surface adhesion of the EVA matrix. And finally, drying the sample at room temperature for 24 hours to prepare the CNT/EVA shape memory composite material film which is respectively marked as CNT/EVA 10 、CNT/EVA 20 、CNT/EVA 30 And CNT/EVA 40 。
The effect of sonication time on the properties of the CNT/EVA shape memory composite was investigated as follows.
As shown in fig. 1, (a-d) show surface topography SEM images of CNT/EVA shape memory composite films prepared at different ultrasonic treatment times, it can be found that the CNT adsorption amount on the EVA surface increases with the increase of the ultrasonic treatment time, as shown in fig. 1(a), after 10min of ultrasonic treatment, the CNT embedded in the matrix and the CNT entangled with each other do not completely cover the matrix surface, and there is a part of matrix exposed, thereby affecting the conductivity of the composite material. However, under the action of continuous ultrasound, the other end of the CNT inserted into the matrix continuously entangles free CNT, until after 20min of ultrasound treatment, the CNT adsorption amount on the surface of the EVA matrix tends to be saturated, and a functional layer of a complete conductive network structure is formed on the surface layer of the EVA (as shown in fig. 1 (e-g). the cross-sectional shape of the CNT/EVA composite material subjected to 20min of ultrasound treatment is shown in fig. 1 (h-k). the CNT serving as the functional layer tightly wraps the EVA matrix to form a complete skin-core structure. furthermore, in fig. 1(j-k), it is clearly observed that a transition interface layer is formed between the EVA matrix partially melted by the action of ultrasound and the CNT partially embedded therein.
As shown in FIG. 2, the mechanical properties of EVA and the composite film thereof are shown, the tensile strength of pure EVA can reach 11.88MPa, but under the continuous ultrasonic action, the tensile strength of the CNT/EVA composite material is gradually reduced. The tensile strength of the composite material subjected to ultrasonic processing for 10min is reduced to 11.28MPa, and is reduced by about 5.05% compared with that of pure EVA, the tensile strength of the composite material subjected to ultrasonic processing for 20min is reduced to 11.12MPa and is reduced by 6.39%, the tensile strength of the composite material subjected to ultrasonic processing for 30min is reduced to 10.89MPa and is reduced by about 8.33%, and the tensile strength of the composite material subjected to ultrasonic processing for 40min is reduced to 10.12MPa and is reduced by 14.81%. This is caused by the high energy generated by the ultrasonic wave breaking the cross-linked molecular chains of part of the EVA matrix, so the ultrasonic time is not suitable to be too long. In general, modulus is defined as the ratio of stress to strain of a material under stress, and thus from the above analysis, it is not difficult to derive that the modulus of a composite material also exhibits a decreasing property with increasing ultrasound time. In a word, experimental results show that the CNT/EVA composite material prepared by proper ultrasonic treatment time has excellent mechanical property and ductility, and the application of the CNT/EVA composite material in flexible intelligent equipment such as executive devices and the like is guaranteed.
The CNT functional layer generates a large amount of joule heat through electric-thermal conversion and transfers the joule heat to the EVA layer serving as a thermal response driving layer, so that the electric-driven shape memory behavior of the CNT/EVA composite material is realized. FIG. 3 shows the electrical conductivity of composites prepared with different sonication times, with significantly higher electrical conductivity of the CNT/EVA composite as sonication time increases, however, with lower electrical conductivity as sonication time increases, wherein the CNT/EVA composite decreases 20 The conductivity of the nano-carbon nano-tube reaches 211.64S/m, which is respectively compared with CNT/EVA 10 (78.82S/m)、CNT/EVA 30 (184.33S/m) and CNT/EVA 40 (160.74S/m) was higher than 168.51%, 14.82% and 31.67%. This is consistent with the characterization results of SEM, and it is confirmed again that the adsorption amount of CNTs on the EVA surface reaches the saturation state after 20min of ultrasound, and the excessive ultrasound treatment time may destroy the CNT conductive network layer whose surface has been entangled with each other and embedded in the EVA matrix, thereby causing the decrease of the conductivity of the composite material.
Therefore, the ultrasonic treatment time is selected to be 20min for preparing the CNT/EVA composite material (the CNT/EVA refers to the CNT/EVA 20 ) And subsequent researches on thermal property, shape memory property and electrothermal conversion property are carried out, so that the high modulus, high breaking strength and high conductivity of the composite material are maintained. The method comprises the following specific steps:
the shape memory behavior of CNT/EVA composites is achieved by crystalline melt transition of crosslinked EVA. As shown in fig. 4, it can be found in the DSC curve that the crystallization temperature (Tc) and melting temperature (Tm) of the CNT/EVA composite material are substantially unchanged compared to pure EVA, respectively at 58.9 ℃ and 76.7 ℃, and there is only a difference of 0.34% and 1.05%, which indicates that the infiltration network structure formed by the CNTs embedded in the EVA matrix does not have a great influence on the crystallization behavior and crystal structure of EVA, and the influence of the CNT introduction on the thermal performance of EVA is very little.
The electrical driving response of the CNT/EVA composite is essentially still achieved by the form of indirect thermal driving, so it is necessary to characterize the thermal driving shape memory properties of the composite first. The process of the CNT/EVA composite material returning from the temporary shape to the permanent shape at 100 ℃ is shown in fig. 5.
In the initial stage of heat recovery, 5s is needed for the sample to recover from the temporary shape (1 ℃) to 10 ℃, after 8s, the sample can recover to 50 ℃ and reach 90 ℃ in 10s, and the relatively slow recovery rate in this stage can be interpreted as that a certain time is needed for the heat stage to transfer the temperature to the sample and for the EVA molecular chain to respond entropy driving and recover. But then only 4s of sample is needed to return from 90 ° to 140 °, and the rate of return is abruptly increased. Continuing to hold the temperature, the sample may slowly return to above 170 ° to near the original shape, but not completely to the original shape. R of composite material f And R r The values are shown in Table 1, and it can be seen that R of the composite material f Up to 98%, R r 97% was also achieved, indicating that the composite had excellent thermally driven shape memory properties.
TABLE 1 shape memory fixation and recovery of CNT/EVA composite films
This example further studies the electrothermal conversion effect of the CNT/EVA composite at different driving voltages, and the electrically driven shape memory performance at the optimal driving voltage. FIG. 6 shows the temperature rise process of the CNT/EVA composite material at different voltages, the temperature rise rate of the CNT/EVA is increased along with the increase of the voltage, 40mm × 5mm composite material sample bars can be heated to more than 100 ℃ within 13s under 10V direct current voltage, and the infrared thermal imaging result is shown in FIG. 7. This is 27.78%, 45.83% and 75.47% faster than the temperature rise at 9V (18s), 8V (24s) and 7V (53s) voltages, respectively. And under the drive of a voltage of 6V, the average temperature of the surface of the composite material can only reach 80.23 ℃ at most and can not rise to more than 100 ℃ all the time. Therefore, in the subsequent electrically driven shape memory experiment, 10V was used as the driving voltage of the composite material.
As shown in fig. 8, the electrically driven shape memory recovery process of the CNT/EVA composite material under the driving of 10V dc voltage and the temperature change of the surface of the composite material during the recovery process are shown. After the test is started, the CNT/EVA composite material returns to a vertical state within 7s, and the surface temperature is obviously increased; then, gradually returning to the original state within 12s, wherein the highest temperature of the surface of the composite material reaches 100 ℃; finally, the composite material returns to the original shape within 19s, and the surface average temperature of the composite material in the temperature rising area rises to be more than 100 ℃.
The test result proves that the CNT/EVA composite material prepared by the swelling ultrasonic method has excellent electrothermal conversion performance and electric drive shape memory performance, and can return to the original shape from the temporary shape in a short time only under the drive voltage of 10V.
In the above embodiments and their alternatives, the ultrasonic time can be determined according to practical application conditions within 30min or more during the preparation of the CNT dispersion.
In the above embodiments and alternatives, the concentration of the CNT dispersion can also be 1mg/mL, 1.5mg/mL, 2.5mg/mL, 3mg/mL, and the like.
In the above examples and alternatives, the volume ratio of DMF to water may also be 2: 8. 2.5: 7.5, 3.5: 6.5, 4: 6, and the like.
In the above embodiment and its alternative, the mass ratio of the EVA masterbatch to the crosslinking agent DCP may also be 95: 5. 96: 4. 98: 2, etc.
In the above embodiments and alternatives, the temperature of swelling may also be 35 ℃, 38 ℃, 42 ℃, 45 ℃ and the like.
The foregoing has outlined rather broadly the preferred embodiments and principles of the present invention and it will be appreciated that those skilled in the art may devise variations of the present invention that are within the spirit and scope of the appended claims.
Claims (10)
1. The preparation method of the CNT/EVA shape memory composite material is characterized by comprising the following steps:
(1) preparing CNT dispersion liquid and preparing an EVA film;
(2) placing the EVA film in a xylene solution for swelling;
(3) placing the EVA film subjected to swelling treatment in CNT dispersion liquid under an ice bath condition and carrying out ultrasonic treatment; and then taking out the film, cleaning and drying to prepare the CNT/EVA shape memory composite material.
2. The method of claim 1, wherein the step (1) of preparing the CNT/EVA shape memory composite comprises:
the CNT powder was added to a solution containing DMF and water, followed by ultrasonication under ice bath conditions for at least 30min to obtain a CNT dispersion.
3. The method for preparing the CNT/EVA shape memory composite material of claim 2, wherein the concentration of the CNT dispersion is 1-3 mg/mL.
4. The method for preparing the CNT/EVA shape memory composite material of claim 2, wherein the volume ratio of DMF to water is (2-4): (8-6).
5. The method of claim 1, wherein the step (1) of preparing the EVA film comprises:
premixing EVA master batch and a cross-linking agent DCP according to a target mass ratio, and then carrying out melt extrusion blending;
and then placing the mixture particles subjected to melt extrusion into a mold, placing the mold in a flat vulcanizing machine for preheating, pressurizing to 10MPa, raising the temperature to 150 ℃, and carrying out hot pressing for 1 hour to obtain the EVA film.
6. The method for preparing CNT/EVA shape memory composite material of claim 5, wherein the target mass ratio is (95-98): (5-2).
7. The method for preparing CNT/EVA shape memory composite material of claim 5, wherein the temperatures of the heating zones of the screw extruder used for melt extrusion blending are set to 85 ℃, 90 ℃, 95 ℃ and 100 ℃.
8. The method for preparing the CNT/EVA shape memory composite material of claim 1, wherein in the step (2), the swelling temperature is 35-45 ℃, and constant-temperature swelling is adopted.
9. The method for preparing the CNT/EVA shape memory composite material of claim 1, wherein the ultrasonic treatment time in the step (3) is 10-40 min.
10. A CNT/EVA shape memory composite material manufactured by the manufacturing method according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210816421.6A CN115058046A (en) | 2022-07-12 | 2022-07-12 | CNT/EVA shape memory composite material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210816421.6A CN115058046A (en) | 2022-07-12 | 2022-07-12 | CNT/EVA shape memory composite material and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115058046A true CN115058046A (en) | 2022-09-16 |
Family
ID=83207022
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210816421.6A Pending CN115058046A (en) | 2022-07-12 | 2022-07-12 | CNT/EVA shape memory composite material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115058046A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112376266A (en) * | 2020-09-24 | 2021-02-19 | 浙江理工大学 | Composite fiber with shape memory performance and strain sensing performance and preparation method thereof |
| CN113265088A (en) * | 2021-05-18 | 2021-08-17 | 浙江理工大学 | Preparation method of ethylene-vinyl acetate copolymer porous shape memory material |
| CN113337033A (en) * | 2021-06-29 | 2021-09-03 | 哈尔滨工业大学 | Preparation of thermally-deformed support arm and method for regulating and controlling unfolding state of space reflector by using thermally-deformed support arm |
-
2022
- 2022-07-12 CN CN202210816421.6A patent/CN115058046A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112376266A (en) * | 2020-09-24 | 2021-02-19 | 浙江理工大学 | Composite fiber with shape memory performance and strain sensing performance and preparation method thereof |
| CN113265088A (en) * | 2021-05-18 | 2021-08-17 | 浙江理工大学 | Preparation method of ethylene-vinyl acetate copolymer porous shape memory material |
| CN113337033A (en) * | 2021-06-29 | 2021-09-03 | 哈尔滨工业大学 | Preparation of thermally-deformed support arm and method for regulating and controlling unfolding state of space reflector by using thermally-deformed support arm |
Non-Patent Citations (1)
| Title |
|---|
| LU XU ET AL.: "Electrothermally-Driven Elongating-Contracting Film Actuators Based on Two-Way Shape Memory Carbon Nanotube/Ethylene-Vinyl Acetate Composites" * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Raja et al. | Thermal, mechanical and electroactive shape memory properties of polyurethane (PU)/poly (lactic acid)(PLA)/CNT nanocomposites | |
| Nguyen et al. | 4D-printing—Fused deposition modeling printing and PolyJet printing with shape memory polymers composite | |
| Zhang et al. | Electrically/infrared actuated shape memory composites based on a bio-based polyester blend and graphene nanoplatelets and their excellent self-driven ability | |
| Wei et al. | Preparation of polylactide/poly (ether) urethane blends with excellent electro-actuated shape memory via incorporating carbon black and carbon nanotubes hybrids fillers | |
| Fei et al. | A spatially and temporally controlled shape memory process for electrically conductive polymer–carbon nanotube composites | |
| Bai et al. | Thermal and water dual-responsive shape memory poly (vinyl alcohol)/Al 2 O 3 nanocomposite | |
| Wang et al. | Preparation and property investigation of multi-walled carbon nanotube (MWCNT)/epoxy composite films as high-performance electric heating (resistive heating) element. | |
| Liu et al. | Electroactive shape memory composites with TiO2 whiskers for switching an electrical circuit | |
| CN102144056A (en) | Method of manufacturing composite conducting fibres, fibres obtained by the method, and use of such fibres | |
| Bi et al. | Near infrared-induced shape memory polymer composites with dopamine-modified multiwall carbon nanotubes via 3D-printing | |
| CN106566398B (en) | A kind of Conducting Polymer Nanocomposites and preparation method thereof of three shapes shape memory function | |
| Guo et al. | Thermal conductivity of PVDF/PANI-nanofiber composite membrane aligned in an electric field | |
| CN112376266B (en) | Composite fiber with shape memory performance and strain sensing performance and preparation method thereof | |
| Fan et al. | Thermal conductivity and mechanical properties of high density polyethylene composites filled with silicon carbide whiskers modified by cross-linked poly (vinyl alcohol) | |
| KR20130048934A (en) | PVDF NANOFIBROUS MEMBRANE WITH HIGH RATIO OF β-PHASE, PIEZOELECTRIC AND FERROELECTRIC PROPERTIES, AND MANUFACTURING METHOD OF THE SAME | |
| CN113861538A (en) | Self-repairing conductive ring oxidized natural rubber composite material and preparation method thereof | |
| Kurup et al. | Shape memory properties of polyethylene/ethylene vinyl acetate/carbon nanotube composites | |
| Zheng et al. | Controllable distribution of conductive particles in polymer blends via a bilayer structure design: a strategy to fabricate shape-memory composites with tunable electro-responsive properties | |
| CN104861183A (en) | Nanometer tectonic polyvinylidene fluoride composite material and preparation method thereof | |
| US20200163255A1 (en) | Highly elastic, thermally conductive and optically transparent polymer based material for heat dissipation in flexible/wearable electronics and other thermal management applications | |
| CN111269510A (en) | Compatible ethylene-tetrafluoroethylene copolymer nano composite material and preparation method thereof | |
| Zhang et al. | Polyurethane-polysiloxane copolymer compatibilized SiR/TPU TPV with comfortable human touch toward wearable devices | |
| Huang et al. | High-strength, self-reinforcing and recyclable multifunctional lignin-based polyurethanes based on multi-level dynamic cross-linking | |
| CN115058046A (en) | CNT/EVA shape memory composite material and preparation method thereof | |
| CN112375368B (en) | Carbon-based flexible conductive film, preparation method and application |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220916 |