A polydimethylsiloxane / carbon nanotube composite material, a preparation method and application thereof

Abstract

The application discloses a preparation method of a polydimethylsiloxane / carbon nanotube composite material, which comprises the following steps: loading configured cellulose acetate spinning solution into a syringe, collecting electrospun fibers under different spinning parameter conditions by using a receiving roller and drying the electrospun fibers to obtain an electrospun fiber membrane; adding carbon nanotubes into a sodium dodecyl sulfate solution, sequentially performing magnetic stirring, ultrasonic dispersion and magnetic stirring, filtering and collecting, and drying to obtain modified carbon nanotubes; adding the electrospun fiber membrane into a mold, mixing and stirring the modified carbon nanotubes with a n-hexane solvent and ultrasonically dispersing the modified carbon nanotubes, adding polydimethylsiloxane and a curing agent into the mold in proportion, pouring the mixture into the mold, removing bubbles in a vacuum state, and obtaining the polydimethylsiloxane / carbon nanotube composite material, which has good stability and durability and can be used for monitoring sports of different parts of a human body.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of polydimethylsiloxane / carbon nanotube composite material, preparation method and application, specifically to a kind of cellulose electrospun fiber regulated polydimethylsiloxane / carbon nanotube composite material mechanical and electrical performance method, belong to polymer conductive composite material technical field. BACKGROUND

[0002] Organic silicone elastomer has important applications in biomedical applications due to its low curing temperature, stretchability, high affinity and high thermal stability, and other excellent properties. Polydimethylsiloxane is one of the commonly used organic silicone elastomers, which is a highly electrically insulating and thermally insulating material, and can be used as a pressure sensor substrate and other materials. Electrospun fibers have many advantages such as high mechanical strength, large specific surface area and high porosity, and are an ideal choice for reinforcing polymer materials. Carbon nanotubes are a kind of filling material with excellent electrical conductivity, which has great attraction for the development of conductive composites. Although the incorporation of carbon nanotubes can improve the electrical conductivity of polymer composites, there are still problems of uneven dispersion of carbon nanotubes in the base material and easy accumulation of carbon nanotubes, which affects the mechanical and electrical properties of the composite material and limits its application in the field of flexible stress and strain sensors. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art and provide a kind of polydimethylsiloxane / carbon nanotube composite material, preparation method and application, which solves the problem of uneven dispersion of carbon nanotubes in polydimethylsiloxane base material by using CA electrospun fiber, and improves the mechanical and electrical properties of polydimethylsiloxane / carbon nanotube composite material.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0005] In a first aspect, the present application provides a preparation method of a polydimethylsiloxane / carbon nanotube composite material, comprising the following steps:

[0006] The prepared cellulose acetate spinning solution is loaded into a syringe, and electrospun fibers are collected using a receiving roller under different spinning parameter conditions and dried to obtain an electrospun fiber membrane;

[0007] The carbon nanotubes are added to a sodium dodecyl sulfate solution, and sequentially subjected to magnetic stirring, ultrasonic dispersion and magnetic stirring, and then filtered and collected, and dried to obtain modified carbon nanotubes;

[0008] The electrospun fiber membrane is added to a mold, the modified carbon nanotubes are mixed with n-hexane solvent and subjected to stirring and ultrasonic dispersion, and the polydimethylsiloxane and curing agent are added in a certain proportion for compounding, poured into the mold, and vacuumed to remove bubbles to obtain a polydimethylsiloxane / carbon nanotube composite material.

[0009] Further, the cellulose acetate spinning solution is cellulose acetate dissolved in a mixed solvent of acetone and N,N-dimethylacetamide, and the mass ratio of the acetone and N,N-dimethylacetamide is 2:1.

[0010] Further, the cellulose acetate has a mass concentration of 16%, and the acetyl content ranges from 37% to 42%.

[0011] Further, the different spinning parameter conditions include:

[0012] The spinning solution supply speed is 0.4-0.8 ml / h, the receiving roller rotation speed is 200-1200 rpm / min, the spinning voltage is 20 kV, the spinning distance is 20 cm, and the electrospun fibers are dried at 80°C.

[0013] Further, the modified carbon nanotubes are preferably multi-walled carbon nanotubes.

[0014] Further, the magnetic stirring, ultrasonic dispersion and magnetic stirring are sequentially performed for 15 min, 1 h and 24 h, respectively.

[0015] Further, the polydimethylsiloxane is Sylgard 184.

[0016] Further, the mass ratio of the polydimethylsiloxane to the curing agent is 10:1, the electrospun fiber content of the electrospun fiber membrane is 1 wt% of the polydimethylsiloxane / carbon nanotube composite material, and the mass content of the carbon nanotubes is 5 wt%-10 wt% of the polydimethylsiloxane / carbon nanotube composite material.

[0017] In a second aspect, the application provides a polydimethylsiloxane / carbon nanotube composite material prepared according to the method of any one of the above claims.

[0018] Further, the polydimethylsiloxane / carbon nanotube composite material is applied to a motion monitoring sensor for different parts of the human body.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] The application solves the problem of uneven dispersion of carbon nanotubes in a polydimethylsiloxane base material by using electrospun fibers in cellulose acetate, effectively improving the mechanical and electrical properties of the polydimethylsiloxane / carbon nanotube composite material. DETAILED DESCRIPTION

[0021] The present application is further described below, and the endpoints of the ranges of values (as well as any values within a range) disclosed herein are not limited to the precise values stated. The endpoints of the ranges of values are provided as example embodiments and are intended to be illustrative of a range of values. Any one single endpoint is not intended to be the only value within a range. Any individual value can be combined with any other individual value to produce a new range of values.

[0022] Firstly, the present application provides a polydimethylsiloxane / carbon nanotube composite material preparation method, comprising the following steps:

[0023] The prepared cellulose acetate spinning solution is loaded into a syringe, and the electrospun fibers are collected using a receiving roller under different spinning parameter conditions and dried to obtain an electrospun fiber membrane;

[0024] The carbon nanotubes are added to a sodium dodecyl sulfate solution, and sequentially subjected to magnetic stirring, ultrasonic dispersion and magnetic stirring for 15 min, 1 h and 24 h respectively, filtered and collected, and dried to obtain modified carbon nanotubes;

[0025] The electrospun fiber membrane is added into a mold, the modified carbon nanotubes are mixed with n-hexane solvent and stirred and ultrasonically dispersed, the polydimethylsiloxane and the curing agent are added into the mold in a certain proportion, and bubbles are removed under vacuum to obtain a polydimethylsiloxane / carbon nanotube composite material.

[0026] Specifically, the cellulose acetate spinning solution is cellulose acetate dissolved in a mixed solvent of acetone and N,N-dimethylacetamide, and the mass ratio of acetone and N,N-dimethylacetamide is 2:1; the mass concentration of cellulose acetate is 16%, and the acetyl content is in the range of 37%-42%.

[0027] In specific embodiments, different spinning parameter conditions include:

[0028] The spinning solution supply speed is 0.4-0.8 ml / h, the receiving roller rotation speed is 200-1200 rpm / min, the spinning voltage is 20 kV, the spinning distance is 20 cm, and the electrospun fibers are dried at 80°C for standby.

[0029] Preferably, the spinning solution supply speed is 0.6 ml / h, and the receiving roller rotation speed is 600 rpm / min.

[0030] The polydimethylsiloxane in the embodiments of the present application is Sylgard 184, and the mass ratio of polydimethylsiloxane to curing agent is 10:1.

[0031] The electrospun fiber content of the electrospun fiber membrane is 1 wt% of the polydimethylsiloxane / carbon nanotube composite material, and the mass content of the carbon nanotubes is 5 wt%-10 wt% of the polydimethylsiloxane / carbon nanotube composite material.

[0032] The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0033] Example 1:

[0034] The CA powder was dissolved in a solvent (acetone / N,N-dimethylacetamide = 2 / 1, w / w) to prepare a spinning solution with a CA concentration of 16wt%, and stirred at room temperature for 12 hours to fully dissolve the CA powder and form a uniform spinning solution.

[0035] The spinning parameters were voltage 20kV, spinning rate 0.8ml / h, receiving distance 15cm, and receiving roller speed 200rpm, to obtain an electrospun nanofiber membrane.

[0036] A 1.6g / L sodium dodecyl sulfate solution was prepared, and a certain amount of CNT was added to the prepared solution, which was fully dissolved by stirring with a magnetic stirrer at a low temperature. The solution was initially dispersed by stirring with a magnetic stirrer for 15min, and then ultrasonically cleaned for 1h using an ultrasonic cleaner, and stirred for 24h using a magnetic stirrer. The solution was collected by vacuum filtration using a microfiltration membrane, and vacuum dried at 60°C for standby use.

[0037] 7% of the modified CNT powder was weighed and added to the n-hexane solvent, and stirred for 30min using a magnetic stirrer to initially disperse the CNT, and then ultrasonically cleaned for 1h to uniformly disperse the CNT. The PDMS matrix was poured into the modified CNT solution at a weight ratio of 10:1 of the bulk (part A) to the curing agent (part B), and stirred uniformly using n-hexane as a dispersant (PDMS:n-hexane = 1:9, w / w). Then the mixed solution was poured into a polytetrafluoroethylene mold, and the mixed solution was degassed in a vacuum pump driven dryer to remove air bubbles.

[0038] Then, according to the mass of the substrate, the mass of the fiber membrane with a content of 1wt% was calculated, and the pre-weighed CA nanofiber membrane was placed in the mold. The mold was placed in a vacuum driven dryer to remove air bubbles, and the mold was placed in a fume hood at room temperature for 12h to completely evaporate the n-hexane solvent. Finally, the mold was cured in an oven at 80°C for 4h to obtain a polydimethylsiloxane / carbon nanotube composite material.

[0039] With the introduction of CA electrospun fibers, the tensile strength of the composite material increased from 2.1MPa to 3.7MPa, and the Young's modulus increased from 1.42MPa to 28.26MPa. In addition, when the composite material with a pre-cut crack was stretched, the tensile strength increased from 0.2MPa to 2.1MPa, and the anti-fracture performance was significantly improved.

[0040] The relationship between the resistance change rate of the conductive composite material and the strain is almost linear, and the sensitivity factor of the conductive composite material increases from 2.1 to 3.9 with the introduction of CA electrospun fibers.

[0041] Example two:

[0042] The CA powder was dissolved in a solvent (acetone / N,N-dimethylacetamide = 2 / 1, w / w) to prepare a spinning solution with a CA concentration of 16wt%, and stirred at room temperature for 12 hours to fully dissolve the CA powder and form a uniform spinning solution. The spinning parameters were voltage 20kV, spinning rate 0.6ml / h, receiving distance 15cm, and receiving roller speed 600rpm, to obtain an electrospun nanofiber membrane.

[0043] A 1.6g / L sodium dodecyl sulfate solution was prepared and fully dissolved by stirring with a magnetic stirrer under slight heating. A certain amount of CNT was added to the previously prepared solution, and was initially dispersed by stirring with a magnetic stirrer for 15min, and then was uniformly dispersed by ultrasonic cleaning for 1h and stirring with a magnetic stirrer for 24h. The dispersion was collected by vacuum filtration with a microfiltration membrane and was dried at 60°C under vacuum for later use. 7% modified CNT powder was weighed and added to n-hexane solvent, and was initially dispersed by stirring with a magnetic stirrer for 30min, and then was uniformly dispersed by ultrasonic cleaning for 1h.

[0044] PDMS was poured into the modified CNT solution, n-hexane was used as a dispersant (PDMS:n-hexane = 1:9, w / w), and the mixture was stirred until uniform. Then the mixed solution was poured into a polytetrafluoroethylene mold, and the mixed solution was degassed in a vacuum pump driven dryer to remove bubbles. Then the mass of the fiber membrane containing 1wt% was calculated according to the mass of the substrate, the pre-weighed CA nanofiber membrane was placed in the mold, and the mold was placed in a vacuum driven dryer to remove bubbles. The mold was placed in a fume hood at room temperature for 12h to completely evaporate the n-hexane solvent, and finally was cured in an oven at 80°C for 4h to obtain a polydimethylsiloxane / carbon nanotube composite material.

[0045] With the introduction of CA electrospun fibers, the tensile strength of the composite material increased from 2.1MPa to 3.7MPa, and the Young's modulus increased from 1.42MPa to 26.53MPa; in addition, when the composite material was stretched with a pre-cut crack, the tensile strength increased from 0.2MPa to 2.3MPa, and the anti-fracture performance was significantly improved.

[0046] The relationship between the resistance change rate of the conductive composite material and the strain is almost linear, and the sensitivity factor of the conductive composite material increases from 2.1 to 3.8 with the introduction of CA electrospun fibers.

[0047] Example three:

[0048] The CA powder was dissolved in a solvent (acetone / N,N-dimethylacetamide = 2 / 1, w / w) to prepare a spinning solution with a CA concentration of 16wt%, and stirred at room temperature for 12 hours to fully dissolve the CA powder and form a uniform spinning solution. The spinning parameters were as follows: voltage 20kV, spinning rate 0.4ml / h, receiving distance 15cm, and receiving roller speed 1200rpm. An electrospinning nanofiber membrane was obtained.

[0049] A 1.6g / L sodium dodecyl sulfate solution was prepared and fully dissolved by stirring with a magnetic stirrer under slight heating. A certain amount of CNTs was added to the prepared solution, stirred with a magnetic stirrer for 15min to preliminarily disperse, then ultrasonically cleaned for 1h, and stirred with a magnetic stirrer for 24h. The CNTs were collected by vacuum filtration with a microfiltration membrane and dried at 60°C under vacuum for standby use.

[0050] 7% modified CNT powder was weighed and added to n-hexane solvent, stirred with a magnetic stirrer for 30min to preliminarily disperse, then ultrasonically cleaned for 1h to uniformly disperse. PDMS was poured into the modified CNT solution, n-hexane was used as a dispersant (PDMS:n-hexane = 1:9, w / w), stirred uniformly, then the mixed solution was poured into a polytetrafluoroethylene mold, and the mixed solution was degassed in a vacuum pump driven dryer to remove bubbles.

[0051] Then, according to the mass of the substrate, the mass of the fiber membrane with a content of 1wt% was calculated, the pre-weighed CA nanofiber membrane was placed in the mold, the mold was placed in a vacuum driven dryer to remove bubbles, the mold was placed in a fume hood at room temperature for 12h to completely evaporate the n-hexane solvent, and finally the mold was cured in an oven at 80°C for 4h to obtain a polydimethylsiloxane / carbon nanotube composite material.

[0052] With the introduction of CA electrospun fibers, the tensile strength of the composite material increased from 2.1MPa to 3.5MPa, and the Young's modulus increased from 1.42MPa to 54.46MPa; in addition, when the composite material was stretched with a pre-cut crack, the tensile strength increased from 0.2MPa to 1.7MPa, and the anti-fracture performance was significantly improved.

[0053] The resistance change rate of the conductive composite material was almost linearly related to the strain, and with the introduction of CA electrospun fibers, the sensitivity factor of the conductive composite material increased from 2.1 to 3.6.

[0054] Example Four:

[0055] The polydimethylsiloxane / carbon nanotube composite material prepared in any of the above examples has good stability and durability, and can be applied in a motion monitoring sensor for monitoring the motion of different parts of the human body.

[0056] The above description is only the preferred embodiment of the present application, it should be pointed out that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and variations can be made, which should be considered as the protection scope of the present application.

Claims

1. A method for preparing a polydimethylsiloxane / carbon nanotube composite material, characterized in that, Includes the following steps: The prepared cellulose acetate spinning solution was loaded into a syringe, and the electrospun fibers were collected using a receiving roller under different spinning parameter conditions and then dried to obtain an electrospun fiber membrane. Carbon nanotubes were added to a sodium dodecyl sulfate solution and subjected to magnetic stirring, ultrasonic dispersion, and magnetic stirring in sequence. The mixture was then filtered, collected, and dried to obtain modified carbon nanotubes. Electrospun fiber membrane is added to the mold, modified carbon nanotubes are mixed and stirred with n-hexane solvent and ultrasonically dispersed, polydimethylsiloxane and curing agent are added in proportion to form a composite, poured into the mold, and vacuum degassing is performed to obtain polydimethylsiloxane / carbon nanotube composite material.

2. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 1, characterized in that, The cellulose acetate spinning solution is cellulose acetate dissolved in a mixed solvent of acetone and N,N-dimethylacetamide, wherein the mass ratio of acetone to N,N-dimethylacetamide is 2:

1.

3. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 2, characterized in that, The cellulose acetate has a mass concentration of 16%, and the acetyl content ranges from 37% to 42%.

4. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 1, characterized in that, The different spinning parameters include: The spinning solution supply rate is 0.4 ~ 0.8 ml / h, the receiving roller speed is 200 ~ 1200 rpm / min, the spinning voltage is 20kV, the spinning distance is 20 cm, and the electrospun fibers are dried at 80℃.

5. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 1, characterized in that, The modified carbon nanotubes are preferably multi-walled carbon nanotubes.

6. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 1, characterized in that, Magnetic stirring, ultrasonic dispersion, and magnetic stirring were performed sequentially for 15 min, 1 h, and 24 h, respectively.

7. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 1, characterized in that, The polydimethylsiloxane is Sylgard 184.

8. The method for preparing a polydimethylsiloxane / carbon nanotube composite material according to claim 1, characterized in that, The mass ratio of polydimethylsiloxane to curing agent is 10:1, the electrospun fiber content of the electrospun fiber membrane is 1 wt% of the polydimethylsiloxane / carbon nanotube composite material, and the mass content of carbon nanotubes is 5 wt%-10 wt% of the polydimethylsiloxane / carbon nanotube composite material.

9. A polydimethylsiloxane / carbon nanotube composite material, characterized in that, The polydimethylsiloxane / carbon nanotube composite material is prepared according to any one of claims 1-8.

10. The polydimethylsiloxane / carbon nanotube composite material according to claim 9, characterized in that, Motion monitoring sensors applied to different parts of the human body.