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CN-118359189-B - Imidazole type ionic liquid composite MCNTs-based solvent-free nanofluid and preparation method thereof

CN118359189BCN 118359189 BCN118359189 BCN 118359189BCN-118359189-B

Abstract

The invention provides an imidazole type ionic liquid composite MCNTs-based solvent-free nanofluid and a preparation method thereof, wherein acidified MCNTs-OH is taken as a core, the MCNTs-OH is combined with an ionic liquid, pi electrons on the surfaces of the ionic liquid and a carbon nano tube are crosslinked in a cationic-pi or pi-pi form, so that the carbon nano tube can be dispersed, the prepared MCNTs-based solvent-free nanofluid comprises 5-15% by mass of MCNTs and 85-95% by mass of imidazole type ionic liquid, the mass percentages of the MCNTs and the imidazole type ionic liquid are added to be 100%, the MCNTs are taken as the core, and the ionic liquid is a neck-shaped layer and a crown-shaped layer. According to the invention, the ionic liquid with high stability, low toxicity and difficult volatilization is introduced to serve as a neck crown structure, and is grafted to the surface of the acidified carbon nano tube core through a covalent bond, so that the preparation method has the advantages of adjustable viscosity, high thermal conductivity, zero volatilization, stable performance and the like.

Inventors

  • HUANG YING
  • NIU QIANQIAN
  • ZONG MENG
  • CHEN CHEN
  • YAN JING
  • TAN XIANGYANG

Assignees

  • 西北工业大学

Dates

Publication Date
20260508
Application Date
20240418

Claims (7)

  1. 1. The MCNTs-based solvent-free nanofluid compounded by imidazole type ionic liquid is characterized by comprising 5-15% of MCNTs and 85-95% of imidazole type ionic liquid by mass percent, wherein the sum of the mass percentages of the MCNTs and the imidazole type ionic liquid is 100%, the MCNTs are taken as cores, and the ionic liquid is taken as a neck-shaped layer and a crown-shaped layer; the average outer diameter of the MCNTs is 5 nm-15 nm, and the length of the MCNTs is 10-30 mu m; The neck-shaped layer is a silane coupling agent, and adopts 3-chloropropyl triethylsilane, 3-chloropropyl trimethoxysilane, (3-chloropropyl) tris (trimethylsiloxy) silane or (3-bromopropyl) triethoxysilane; the crown layer is imidazole salt, and adopts 1-methylimidazole, 1- (2-hydroxyethyl) imidazole, chlorinated 1-butyl-3-methylimidazole, 1-ethyl-3-methylimidazole acetate or chlorinated 1-allyl-3-methylimidazole.
  2. 2. A method for preparing the imidazole ionic liquid composite MCNTs-based solvent-free nanofluid according to claim 1, which is characterized by comprising the following steps: (1) Adding H 2 SO 4 and HNO 3 into MCNTs to prepare an acid solution of the MCNTs, stirring the obtained solution under a heating condition, and cooling the solution to room temperature to obtain black suspension liquid; pouring the black suspension liquid into deionized water, fully stirring, standing, cooling, and performing suction filtration to obtain a black substance, washing the black substance to be neutral, and then performing vacuum drying and grinding to obtain black powder, namely acidified MCNTs-OH; (2) Heating and stirring a neck-shaped layer silane coupling agent and a crown-shaped layer imidazolium salt in a nitrogen atmosphere to obtain imidazole type ionic liquid IL1, cooling and washing impurities in the imidazole type ionic liquid IL1, and then vacuum drying under a heating condition to obtain light yellow mucus; (3) Adding acidified MCNTs-OH into the yellowish mucus obtained in the step (2), stirring, dialyzing, and vacuum drying under the condition of heating to obtain MCNTs-based solvent-free nanofluid.
  3. 3. The preparation method of the MCNTs-based solvent-free nanofluid compounded by the imidazole type ionic liquid is characterized in that the step (1) is characterized in that H 2 SO 4 and HNO 3 with the mass ratio of (1-5): 1 are added into MCNTs while stirring, an acid solution with the MCNTs content of 0.3-wt% is prepared, the obtained solution is refluxed and stirred in an oil bath with the MCNTs content of 50-70 ℃ for 3-6 hours, the solution is cooled to room temperature to obtain black suspension, the black suspension is poured into deionized water at the rate of 20-60 ml/min, the volume ratio of the black suspension to the deionized water is 1:10, the mixture is stirred fully, the mixture is kept stand and cooled, and is subjected to suction filtration by a microfiltration membrane with the mass ratio of 0.1 mu m to obtain black material, the black material is washed to be neutral by the deionized water, and then the black powder, namely the acidified MCNTs-OH is obtained through vacuum drying and grinding.
  4. 4. The preparation method of the MCNTs-based solvent-free nanofluid compounded by the imidazole type ionic liquid according to claim 2 is characterized in that the step (2) is characterized in that neck-shaped layer silane coupling agent and crown-shaped layer imidazole salt with equal molar weight are stirred for 12-36 h under a nitrogen atmosphere, the reaction temperature is 40-100 ℃ to obtain the imidazole type ionic liquid IL1, after cooling, the imidazole type ionic liquid IL1 is washed three times by diethyl ether to wash out impurities, and then the imidazole type ionic liquid IL1 is placed in a vacuum drying oven for drying for 12-36 h at 40-70 ℃ to obtain pale yellow mucus.
  5. 5. The preparation method of the imidazole ionic liquid composite MCNTs-based solvent-free nanofluid according to claim 2, wherein the step (3) is characterized in that acidified MCNTs-OH is added into the pale yellow mucus obtained in the step (2), stirring is carried out for 12-36 h, after the reaction is completed, dialysis is carried out for 24-84 h by using a dialysis bag, and vacuum drying is carried out at 40-70 ℃ for 12-36 h, so that the black solvent-free MCNTs-based solvent-free nanofluid capable of flowing at room temperature is obtained.
  6. 6. The preparation method of the imidazole ionic liquid composite MCNTs-based solvent-free nanofluid, which is disclosed in claim 5, is characterized in that the step (3) is to disperse acidified MCNTs-OH into methanol to prepare a methanol solution with the weight of 1-10%, and then add the methanol solution into the yellowish mucus obtained in the step (2).
  7. 7. The method for preparing the imidazole ionic liquid composite MCNTs-based solvent-free nanofluid according to claim 5, wherein the dialysis bag is a dialysis bag with a relative molecular weight mw=5000.

Description

Imidazole type ionic liquid composite MCNTs-based solvent-free nanofluid and preparation method thereof Technical Field The invention belongs to the field of carbon-based nanofluid materials, and relates to a multi-wall carbon nano tube (MCNTs) -based solvent-free nanofluid. Background The solvent-free nano fluid has various ionic structures and unique room temperature solvent-free flowability, so that the solvent-free nano fluid has wide application prospect in aspects of polymer matrix composite materials, lithium ion batteries, reaction media, self-assembly of nano particles, high-temperature lubricants and the like. The solvent-free nano-fluid technology is used as a surface engineering technology with universality, not only can endow macromolecules and multidimensional nano-materials with special solvent-free flowability, but also can flexibly select modification strategies according to the respective surface chemical structure characteristics of different scale materials so as to realize effective regulation and control of microcompartment, chemical structure and functions of the materials, thereby having very important significance for efficient utilization of various functional materials and preparation and device assembly of composite materials based on various functional structures. The solvent-free nano fluid is a nano particle hybridization material with surface functionalization, has unique room-temperature liquid-like property, and the basic structure can be divided into a core part and a shell part. In theory, the core structure can be zero-dimensional nano particles, one-dimensional nano fibers, two-dimensional nano sheets or even macromolecular materials, and the shell structure is an organic bilayer. The inner layer of the organic bilayer may be referred to as the "inner cap" (corona) which serves to link the inner nanostructure to the outer organic molecule, which is anchored to the "core" by covalent bonds and is an ionic compound having a specific chemical functionality, and the outer layer of the organic bilayer may be referred to as the "outer cap" (canopy) which serves to provide a "flow medium" which is grafted to the inner organic molecule by ionic bonds, typically flexible long chain ions. Nanoparticles that are widely used today mainly include metal and metal oxide nanoparticles and non-metallic nanoparticles. These nanoparticles, which are commonly used for preparing nanofluids, all have thermal conductivity coefficients hundreds to thousands times higher than that of Yu Yeti base fluids, wherein the thermal conductivity coefficients of carbon nanotubes and graphene are more than 5000 times that of pure water. Secondly, the production process is mature, and the large-scale production can be realized. Therefore, the development of the solvent-free carbon-based nanofluid is helpful for remarkably improving the heat conduction performance of the traditional nanofluid. Patent CN102618350A filed by the university of the same company describes a preparation method of a novel core-shell-crown structure solvent-free nano fluid, nano molybdenum disulfide particles are prepared, and a surface modifier with a sulfonic acid group is added for sulfonation treatment, so that the nano molybdenum disulfide particle has the characteristics of simple production and the like, but is mainly used as a lubricant, and the core particle has smaller heat conductivity coefficient and narrower application direction. At present, the preparation method of the MCNTs-based solvent-free nanofluid is not reported yet. The physical modification of the Ionic Liquid (IL) to the carbon material is also called non-covalent modification, and mainly utilizes the interaction force of pi-pi bonds or cation-pi formed between organic cations in the ionic liquid and a carbon atomic layer on the surface of the carbon material to ensure that ionic liquid molecules or polymers thereof can be fixed on the surface of the carbon material in a relatively stable manner, can disperse carbon nano tubes and can not be agglomerated, so that a gel substance which is easy to process is formed, has very strong stability, can keep the physical property at low temperature, and provides possibility for further functionalization of the carbon nano tubes. In summary, as the surface energy of the ionic liquid is relatively low, the ionic liquid can be wrapped around the nano particles, so that the nano particles are stably present, agglomeration of the nano particles is prevented, single dispersion of the nano particles can be realized, and the biggest problem faced by the nano particles in application is solved, so that the novel solvent-free nano fluid is synthesized and the application of the novel solvent-free nano fluid in the novel field is explored, and the ionic liquid has important significance for development of the solvent-free nano fluid. The development of a carbon nano fluid working medium with adjustable viscosity, high thermal