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CN-121991386-A - Composite film based on modified carbon nano tube and thermoplastic polyurethane, and preparation method and application thereof

CN121991386ACN 121991386 ACN121991386 ACN 121991386ACN-121991386-A

Abstract

The invention provides a composite film based on modified carbon nano tube and thermoplastic polyurethane, a preparation method and application thereof, wherein multi-wall carbon nano tube, tannic acid and coupling agent are dispersed in a solvent, nitrogen is introduced for protection, and the mixture is stirred under heating condition for amination pretreatment; adding epoxy group end capped polyether, reacting under heating condition to obtain covalent bonding tannic acid-carbon nano tube powder, dispersing the powder in a solvent, adding a dispersing agent into the solvent, performing ultrasonic treatment to obtain solution I, dissolving polyurethane and a cross-linking agent into the solvent, stirring under heating condition, activating to obtain solution II, mixing the solution I and the solution II, adding nano hydroxyapatite into the solution I, mixing to obtain a dispersion, pouring the dispersion into a mould, and performing cross-linking and curing to obtain the composite membrane. The composite film realizes stable combination of tannic acid and carbon nano tubes through multi-step reaction, and simultaneously constructs a three-dimensional cross-linked network between a matrix and a filler.

Inventors

  • ZHANG DI
  • Ren Qinao
  • HAN ZHIXIONG

Assignees

  • 天津工业大学

Dates

Publication Date
20260508
Application Date
20260403

Claims (10)

  1. 1. The preparation method of the composite film based on the modified carbon nano tube and the thermoplastic polyurethane is characterized by comprising the following steps: dispersing the multi-wall carbon nano tube, tannic acid and a coupling agent in a solvent, introducing nitrogen for protection, and stirring under a heating condition for amination pretreatment; step 2, adding epoxy group end capped polyether into the reaction system obtained in the step 1, reacting under the heating condition, and then filtering, washing and drying to obtain covalently bonded tannic acid-carbon nano tube powder; Step 3, dispersing the covalently bonded tannic acid-carbon nano tube powder in a solvent, adding a dispersing agent into the solvent, and carrying out ultrasonic treatment to obtain a solution I; step 4, dissolving polyurethane and a cross-linking agent in a solvent, stirring under a heating condition, and activating to obtain a solution II; And 5, mixing the solution I and the solution II, adding nano hydroxyapatite into the mixture, mixing the mixture to obtain a dispersion liquid, pouring the dispersion liquid into a mold, and drying, crosslinking and curing the dispersion liquid to obtain the composite film based on the modified carbon nano tube and the thermoplastic polyurethane.
  2. 2. The preparation method of the composite film based on the modified carbon nano tube and the thermoplastic polyurethane, which is disclosed in claim 1, is characterized in that the mass ratio of the multi-wall carbon nano tube, the tannic acid and the coupling agent in the step 1 is (2-3) (0.5-1) (0.25-0.5), the heating condition in the step 1 is at the temperature of 60-80 ℃, the amination pretreatment step in the step 1 is performed for 10-12 h, and the flow rate of nitrogen in the step 1 is 50-80 mL/min.
  3. 3. The preparation method of the composite film based on the modified carbon nano tube and the thermoplastic polyurethane, which is disclosed in claim 1, is characterized in that the coupling agent in the step 1 is an aminosilane coupling agent, the coupling agent in the step 1 is KH-550, the purity of the multi-wall carbon nano tube in the step 1 is more than or equal to 99 wt%, the length is 1-3 mu m, the outer diameter is 8-15 nm, and the solvent in the step 1 is a mixed solvent of ethanol and deionized water in a volume ratio of 3:1.
  4. 4. The method for producing a composite film based on modified carbon nanotubes and thermoplastic polyurethane according to claim 1, wherein the mass ratio of the epoxy-terminated polyether in step 2 to the tannic acid in step 1 is (3-4): (2-3), the epoxy value of the epoxy-terminated polyether in step 2 is 0.5-0.8 eq/100g, the heating condition in step 2 is at 90-100 ℃, the reaction time in step 2 is 7-8 h, the drying step in step 2 is at 60-80 ℃ and the time is 9-10 h.
  5. 5. The preparation method of the composite film based on the modified carbon nano tube and the thermoplastic polyurethane, which is disclosed in claim 1, is characterized in that the adding amount of the dispersing agent in the step 3 is 1-2 wt% of the mass of the covalently bonded tannic acid-carbon nano tube powder, the dispersing agent in the step 3 is polyethylene glycol stearate, the solvent in the step 3 is N, N-dimethylformamide, the power of the ultrasonic step in the step 3 is 250-350W, the time is 40-70 min, the stirring is carried out while the ultrasonic treatment, and the stirring speed is 1500-2000 rpm.
  6. 6. The preparation method of the composite film based on the modified carbon nano tube and the thermoplastic polyurethane, which is disclosed in claim 1, is characterized in that the mass ratio of the polyurethane to the cross-linking agent in the step 4 is 1 (0.01-0.015), the temperature of the activation step in the step 4 is 70-80 ℃ and the time is 30-40 min, the cross-linking agent in the step 4 is an isocyanate cross-linking agent, and the solvent in the step 4 is N, N-dimethylformamide.
  7. 7. The method for preparing a composite film based on modified carbon nanotubes and thermoplastic polyurethane according to claim 1, wherein the addition amount of the covalently bonded tannic acid-carbon nanotube powder in the step 3 is 1-5 wt% of the mass of polyurethane in the step4, the addition amount of the nano-hydroxyapatite in the step 5 is 0.57-0.67-wt% of the mass of polyurethane in the step4, the particle size of the nano-hydroxyapatite in the step 5 is 20-50 nm, and the surface hydroxyl density is not less than 5 mmol/g.
  8. 8. The method for preparing a composite film based on modified carbon nanotubes and thermoplastic polyurethane according to claim 1, wherein the drying step in step 5 is performed at a temperature of 60-80 ℃ for a time of 8-24 h, and the crosslinking and curing step in step 5 is performed at a temperature of 80-90 ℃ for a time of 10-14 h.
  9. 9. A composite film based on modified carbon nanotubes and thermoplastic polyurethane prepared by the preparation method of any one of claims 1 to 8.
  10. 10. The application of the composite film based on the modified carbon nano tube and the thermoplastic polyurethane is characterized in that the application of the composite film in preparing wearable electronic equipment, health monitoring equipment or sports function evaluation equipment and the application of the composite film in preparing a flexible strain sensor.

Description

Composite film based on modified carbon nano tube and thermoplastic polyurethane, and preparation method and application thereof Technical Field The invention belongs to the field of flexible electronic materials, and particularly relates to a composite film based on modified carbon nanotubes and thermoplastic polyurethane, and a preparation method and application thereof. Background With the rapid development of wearable intelligent devices, electronic skin and accurate medical technology, there is an increasing need for flexible strain sensors that combine high sensitivity, excellent stretchability and long-term stability. The flexible strain sensor has the advantages of low cost, convenient integration, simple signal conversion and the like, and has wide application prospect in human motion monitoring, rehabilitation evaluation and human-computer interaction systems. Multi-wall carbon nanotubes (MWCNTs) become ideal conductive fillers for flexible composite sensors due to their excellent electrical conductivity, ultra-high aspect ratio and excellent mechanical properties. However, the original MWCNTs are susceptible to agglomeration due to strong van der waals forces between the tubes, resulting in poor dispersibility in the polymer matrix and insufficient interfacial compatibility, thereby affecting the mechanical flexibility, conductive stability and sensing reversibility of the composite material. Thermoplastic Polyurethane (TPU) is taken as an elastic matrix, has excellent stretchability, biocompatibility and easy processing, but the dispersion defect of unmodified MWCNTs in the TPU generally causes high seepage threshold of a composite material and poor sensing cycle stability, and severely restricts the practical application of the composite material in the field of wearable electronics. Existing MWCNTs surface modification methods include silane coupling agent functionalization, surfactant-mediated dispersion, polymer grafting modification, etc., but these methods often involve toxic chemical reagents, complex synthetic procedures, or high energy consumption problems. Even the existing green modification strategy has the problem of insufficient performance synergy, such as that the chitosan modified MWCNTs/TPU composite material has a Gauge Factor (GF) of only 11.5, an elongation at break of only 250 percent and lacks an electrothermal function, and the polydopamine modified MWCNTs/TPU sensor has a maximum working temperature of 112 ℃ under 10V voltage, but has GF as low as 9.8, and cannot meet the requirement of high-sensitivity motion detection. Tannic Acid (TA) is used as a natural polyphenol compound, has biodegradability, excellent biocompatibility and rich functional groups, and is a green modifier with great potential. However, the traditional non-covalent modification mode only depends on the stacking action of hydrogen bonds and pi-pi, and the durability of the modification effect is insufficient. Disclosure of Invention In view of the above, the present invention aims to overcome the defects in the prior art, and provides a composite film based on modified carbon nanotubes and thermoplastic polyurethane, and a preparation method and application thereof. In order to achieve the above purpose, the technical scheme of the invention is realized as follows: the invention provides a preparation method of a composite film based on modified carbon nano tubes and thermoplastic polyurethane, which comprises the following steps: dispersing the multi-wall carbon nano tube, tannic acid and a coupling agent in a solvent, introducing nitrogen for protection, and stirring under a heating condition for amination pretreatment; Step 2, adding epoxy group end capped polyether (EPE) into the reaction system obtained in the step 1, reacting under the heating condition, and then filtering, washing and drying to obtain covalently bonded tannic acid-carbon nano tube powder (c-TA-MWCNTs); Step 3, dispersing the covalently bonded tannic acid-carbon nano tube powder in a solvent, adding a dispersing agent into the solvent, and carrying out ultrasonic treatment to obtain a solution I; step 4, dissolving polyurethane and a cross-linking agent in a solvent, stirring under a heating condition, and activating to obtain a solution II; And 5, mixing the solution I and the solution II, adding nano hydroxyapatite (n-HA) into the mixture, mixing the mixture to obtain a dispersion liquid, pouring the dispersion liquid into a mold, and drying, crosslinking and solidifying the dispersion liquid to obtain the composite film (c-TA-MWCNTs/TPU) based on the modified carbon nano tube and the thermoplastic polyurethane. Further, the mass ratio of the multiwall carbon nanotubes to the tannic acid to the coupling agent in the step 1 is (2-3) (0.5-1) (0.25-0.5), the heating condition in the step 1 is at the temperature of 60-80 ℃, the amination pretreatment step in the step 1 is 10-12 h, and the flow rate of nitrogen in the step 1 is 50