CN1218979C - Carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene and preparation method thereof - Google Patents

Abstract

The present invention provides a hyper branched poly(p-chloromethyl stryrene) grafted carbon nano-tube and a preparation method thereof. In the method, a carbon nano-tube is processed for causing the surface to be provided with specific initiating groups; atom transfer radical polymerization reaction is used for initiating the polymerization of p-chloromethyl styrene monomers for obtaining the super branched poly-p-chloromethyl styrene grafted carbon nano-tube . The preparation method is simple and easy and has strong controllability; obtained products in organic solvents show good solubility, and the obtained products can be used as special type additive agents of high molecular materials; simultaneously, because of the nanometer grade size, the products can be used as nanometer devices with special functions and can also be used as carriers of mass transmission and transition between different systems; and thereby, the products have a large application prospect at nanometer science aspect, material science aspect biomedicine science aspect, etc.

Description

Carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene and preparation method thereof

Technical field: the present invention relates to a polymer-grafted carbon nanotube, especially a hyperbranched poly-p-chloromethylstyrene-grafted carbon nanotube and a preparation method thereof.

Background technology: Carbon nanotube (Cabon Nanotube, referred to as CNT) is a new type of carbon structure discovered in 1991. It is a tube formed by graphene sheets formed by carbon atoms. Carbon nanotubes are divided into single-wall nanotubes (Single-wall Nanotube, SWNT) and multi-wall carbon nanotubes (Multi-wall Nanotube, MWNT). Its preparation methods mainly include catalytic pyrolysis, arc discharge, template method and laser evaporation.

Due to their small diameter and large aspect ratio, carbon nanotubes are regarded as quasi-one-dimensional nanomaterials. Now it has been confirmed that carbon nanotubes have peculiar electrical properties, super strong mechanical properties, and good adsorption properties, so they have attracted great attention in the field of materials. There are already transistors and displays made of carbon nanotubes.

With the development of nanoscience and technology, various carbon nanotubes with specific properties have gradually attracted people's interest. Richard E.Smalley et al studied the acid treatment of carbon nanotubes carefully in 1998, and obtained the distribution of products under different treatment conditions, which laid a good foundation for further research in the future (Science, 1998, 280 (22 ): 1253-1255). Afterwards, various modified carbon nanotubes and their composite structures were prepared. For example, carbon nanotubes with solvent solubility, carbon nanotube devices with molecular detection functions, and so on.

On the other hand, almost simultaneously and independently, Sawamoto and Matyjaszewski discovered a transition metal-catalyzed "living" controllable free radical polymerization called atom transfer radical polymerization (ATRP). This method soon became a research hotspot in international polymer chemistry, and was hailed as "a new research method in the 21st century". This method is much better than the traditional polymerization method in terms of controlling the target product and maintaining a low molecular weight distribution index, and also avoids the harsh requirements on the polymerization environment in the traditional method. At the same time, due to the wide range of initiators, especially the participation of initiators with functional groups, functional groups can be conveniently introduced into the product, and various block polymers can also be synthesized.

With the development of science and technology, nanostructures and nanodevices with unique structures and functions have gradually gained people's attention, and there are a large number of reports in this area every year. Using the advantages of the ATRP method, combined with carbon nanotubes, various carbon nanotube devices with specific structures can be synthesized, which can greatly expand the application of the above methods and materials, and promote the development of this science and technology field.

Summary of the invention: The purpose of the present invention is to prepare hyperbranched poly-p-chloromethylstyrene-grafted carbon nanotubes through molecular design and atom transfer radical polymerization to meet the needs of different application fields.

Technical scheme of the present invention is as follows:

Through molecular design, the surface of carbon nanotubes is treated to have active groups required for ATRP polymerization, which can initiate the polymerization of monomers containing double bonds; and then use atoms to transfer free radicals in the presence of catalysts and ligands The polymerization reaction triggers the polymerization of p-chloromethyl styrene, and the carbon nanotubes grafted with hyperbranched poly-p-chloromethyl styrene are obtained.

The specific preparation method of the carbon nanotube grafted by hyperbranched poly-p-chloromethylstyrene of the present invention is as follows:

Step (a): 1 weight part of dry carbon nanotube raw material and 0.1-100 weight parts of strong oxidizing acid, use 0-100kHz ultrasonic treatment for 0.1-100hr, heat to 20-200°C, react for 0.5-100hr, filter the Suction filtration, repeated washing several times until neutral, vacuum drying at 0-180°C for 10-30 hours to obtain acidified carbon nanotubes;

Step (b): add 1 weight part of acidified carbon nanotubes obtained in step (a) and 1-100 weight parts of acylating agent, and use 0-100 kHz ultrasonic treatment for 10-1000 min, heat to 20-200 ° C, stir and reflux React for 0.5-100 hours, filter with suction and wash repeatedly to remove the acylating agent, and obtain acylated carbon nanotubes;

Step (c): adding 1 part by weight of the acylated carbon nanotubes obtained in step (b) and 1 to 50 parts by weight of polyol or polyamine, sealing, pumping and filling nitrogen repeatedly three times, and treating with 0 to 100 kHz ultrasonic wave for 10 to 1000 minutes, React at 20-200°C for 1-20 hours, filter with suction, wash repeatedly, and dry in vacuum at 0-180°C to obtain carbon nanotubes with hydroxyl or amine groups on the surface;

Step (d): add 1 weight part of carbon nanotubes with hydroxyl or amino groups on the surface obtained in step (c) and 1 to 50 weight parts of α-halogenated acyl halides, seal, repeatedly pump and fill nitrogen three times, and use 0 to 100 kHz After ultrasonic treatment for 10 to 1000 minutes, react at 20 to 200°C for 1 to 20 hours, suction filter, wash, and vacuum dry at 0 to 180°C to obtain carbon nanotubes with initiator groups on the surface;

Step (e): adding 0.01 to 1 weight part of catalyst, 0.01 to 5 weight parts of ligand, and then adding 1 weight part of carbon nanotubes with initiating groups on the surface obtained in step (d), and 0 to 50 weight parts of solvent, After sealing, fill with Ar or N ₂ for 1-100 min, add 0.01-80 parts by weight of p-chloromethylstyrene monomer, continue to fill with nitrogen or argon for 1-100 min, react at 0-150°C for 0.01-1000 hr, stop the reaction, Dilute in a solvent, filter with suction, wash, and vacuum dry at 0-180°C to obtain carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene with a degree of polymerization of 5-1000. The polymer structure is shown in the figure below:

The carbon nanotubes used in step (a) of the method of the present invention are single-wall or multi-wall carbon nanotubes prepared by catalytic pyrolysis, arc discharge, template method and laser evaporation method.

The strong oxidizing acid used in step (a) of the method of the present invention comprises 0.1～70% acid concentration nitric acid by weight, 0.1～100% acid concentration sulfuric acid by weight, 1/100～100/1 molar ratio nitric acid and sulfuric acid mixed solution, 1/100～ 100/1 molar ratio potassium permanganate and sulfuric acid mixed solution, 1/100-100/1 molar ratio potassium permanganate and hydrochloric acid mixed solution, 1/100-100/1 molar ratio potassium permanganate and nitric acid mixed solution, 1/100～100/1 molar ratio H ₂ O ₂ and sulfuric acid mixed solution, 1/100～100/1 molar ratio H ₂ O ₂ and hydrochloric acid mixed solution or 1/100～100/1 molar ratio H ₂ O ₂ and Nitric acid mixed solution.

The acylating agent used in step (b) of the method of the present invention includes phosphorus trichloride, phosphorus pentachloride, thionyl chloride, phosphorus tribromide, phosphorus pentabromide or thionyl bromide.

The polyol or polyamine material used in the method step (c) of the present invention comprises ethylene glycol, ethylenediamine, glycerol, glycerine triamine, 1,2-propanediol, 1,2-propanediamine, 1,3 -Propylene glycol, 1,3-propylenediamine, 1,4-butanediol, 1,4-butanediamine, 1,2-butanediol, 1,2-butanediamine, 1,3-butanediol , 1,3-butanediamine, butanetriol, butanetriamine, polyethylene glycol or polyethylenediamine.

The α-haloacyl halides used in step (d) of the method of the present invention include α-bromobutyryl bromide, α-bromoisobutyryl bromide, α-bromopropionyl bromide, α-chlorobutyryl chloride, α- Chloroisobutyryl chloride or α-chloropropionyl chloride.

In the method steps (c) and (d) of the present invention, no solvent is used or dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2- Pyrrolidone, chloroform, tetrahydrofuran, ethyl acetate, acetone, acetonitrile, butanone, triethylamine, pyridine or dimethylaminopyridine is used as a solvent or a mixed solvent containing these solvents is used as a reaction medium.

The catalyst used in the process step (e) of the present invention is a metal compound containing Cu(I), Fe(II), Mo(V), Re(V), Ru(II), Ni(I) or Pb(II), such as Cuprous chloride, cuprous bromide, ferrous chloride, ferrous bromide, lithium molybdate, ReO ₂ I(PPh ₃ ) ₂ , RuCl ₂ , Ni(NCN)Br or Pd(OAc) ₂ ; The body is 2-bipyridine, tetramethylethylenediamine, pentamethyl-diethyltriamine, hexamethyl-triethylenetetramine, oxalic acid, malonic acid, succinic acid, phthalic acid , triphenylphosphine or tri-n-butylphosphine; the solvent used is dimethylsulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, Chloroform, dichloromethane, dichloroethane, tetrahydrofuran, ethyl acetate, acetone, methyl ethyl ketone, acetonitrile, propanol, ethanol, methanol or mixtures containing these solvents.

The preparation method provided by the invention is simple and easy to implement, and has strong controllability; the carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene exhibit good solubility in water due to a large number of hydrophilic carboxyl groups This solubility greatly improves the processability of carbon nanotubes, and can be used as a special additive for water-soluble polymer materials; at the same time, due to its nanoscale size, it can be used as a nano-device with special functions to build a specific quantum structure; It can also be used as a carrier for material transfer and transfer between different systems to achieve specific purposes; thus it has a wide range of uses in nanoscience, material science and biomedicine, and has broad application prospects.

Description of drawings:

Figure 1: ¹ H NMR spectrum of carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene

Figure 2: Infrared spectrum of carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene

Specific embodiments: the following examples are further descriptions of the present invention, rather than limiting the scope of the present invention.

Example 1: Multi-walled carbon nanotubes prepared by catalytic pyrolysis as the initial raw material, after acidification and acylation, were connected with ethylene glycol, and then reacted with α-bromoisobutyryl bromide, and in situ by ATRP method The polymerization of p-chloromethyl styrene monomer is initiated, and due to the characteristics of the monomer itself, carbon nanotubes grafted with hyperbranched poly-p-chloromethyl styrene are obtained.

Step (a): In the 100mL single-necked round-bottomed flask equipped with a magnetic stirring rotor, add 2g of dry carbon nanotube raw material and 20mL of 60% concentration of concentrated nitric acid by weight, heat to 120°C after 30min with 40kHz ultrasonic treatment, Stir and react under reflux for 24 hours, filter with φ0.22 μm polytetrafluoroethylene microporous membrane, wash repeatedly with deionized water until neutral, and vacuum dry at 80°C for 24 hours to obtain acidified carbon nanotubes;

Step (b): Add 1.5 g of acidified carbon nanotubes obtained in step (a) and 8 g of thionyl chloride into a 100 mL single-necked round bottom flask equipped with a magnetic stirring rotor, and heat to 60 °C after ultrasonic treatment at 40 kHz for 30 min , stirred and reacted under reflux for 24hr, suction filtered and repeatedly washed to remove thionyl chloride, to obtain acylated carbon nanotubes;

Step (c): In a 100mL single-necked round-bottomed flask equipped with a magnetic stirring rotor, add 1.3g of acylated carbon nanotubes obtained in step (b) and 25g of ethylene glycol, seal with an inversion rubber stopper, and pump repeatedly Nitrogen three times, after 40kHz ultrasonic treatment for 30min, react at 100°C for 24hr, remove unreacted substances and reaction by-products by suction filtration, wash with deionized water repeatedly, and vacuum dry at 80°C to obtain carbon nanotubes with hydroxyl groups on the surface ;

Step (d): In the 100mL single-neck round bottom flask equipped with a magnetic stirring rotor, add 1.1 g of carbon nanotubes with hydroxyl groups on the surface obtained in step (c) and 1 g of α-bromoisobutyryl bromide, Seal the mouth with a rubber stopper, pump nitrogen repeatedly three times, treat with 40kHz ultrasonic wave for 30min, react at 20°C for 1-20hr, remove unreacted substances and reaction by-products by suction filtration, wash with deionized water repeatedly, and vacuum-dry at 80°C. Obtain carbon nanotubes with initiating groups on the surface;

Step (e): In a 50mL single-necked round bottom flask equipped with a magnetic stirring rotor, add 0.6g CuBr, 0.7g ligand PMDETA (pentamethyl-diethyltriamine), and then add the obtained 1g of carbon nanotubes with initiator groups on the surface, solvent DMF 10mL, filled with N ₂ for 10min after sealing, added 10mL of tert-butyl acrylate monomer, continued to fill with N ₂ for 10min, reacted at 100°C for 20hrs, then stopped the reaction, After diluting with chloroform, filter with suction, wash to remove unreacted monomers and catalysts, etc., and dry in vacuum at 80° C. to obtain 1.7 g of carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene.

Fig. 1 has provided the carbon nanotube ¹ H NMR spectrogram of hyperbranched poly-p-chloromethyl styrene graft, polymer main chain (-CH ₂ -: δ=1.2～1.4ppm; -CH-: δ=3.0 ~3.5ppm) and benzene rings (δ=7.1~7.6ppm) prove the structure of poly-p-chloromethylstyrene. The infrared spectrum (Figure 2) clearly demonstrates benzene rings (~1040cm ^-1 ) and methylene groups (~1660cm ^-1 ).

From the thermal analysis data, it can be estimated that the amount of grafted polymer accounts for about 50% of the total mass, and the degree of polymerization is between 10 and 50.

Claims (9)

1. the preparation method of the carbon nanotube of hyperbranched poly-p-chloromethylstyrene grafting, it is characterized in that concrete preparation method is as follows: Step (a): 1 weight part of dry carbon nanotube raw material and 0.1 to 100 weight parts of strong oxidizing acid, ultrasonic treatment at 40 to 100 kHz for 0.1 to 100 hours, heating to 20 to 200 ° C, and reaction for 0.5 to 100 hours to Membrane suction filtration, repeated washing several times until neutral, vacuum drying at 0-180°C for 10-30 hours to obtain acidified carbon nanotubes; Step (b): adding 1 part by weight of the acidified carbon nanotubes obtained in step (a) and 1 to 100 parts by weight of an acylating agent, ultrasonically treating at 40 to 100 kHz for 10 to 1000 minutes, heating to 20 to 200 ° C, stirring and refluxing Reacting for 0.5 to 100 hours, suction filtration and repeated washing to remove the acylating agent to obtain acylated carbon nanotubes; Step (c): adding 1 part by weight of the acylated carbon nanotube obtained in step (b) and 1 to 50 parts by weight of polyol or polyamine, sealing, pumping and filling nitrogen repeatedly three times, and treating with 40 to 100 kHz ultrasonic wave for 10 to 1000 minutes , react at 20-200°C for 1-20 hours, filter with suction, wash repeatedly, and dry in vacuum at 0-180°C to obtain carbon nanotubes with hydroxyl or amine groups on the surface; Step (d): adding 1 weight part of carbon nanotubes with hydroxyl or amino groups on the surface obtained in step (c) and 1 to 50 weight parts of α-halogenated acyl halides, sealing, and repeatedly pumping nitrogen gas three times, at 40 to 100 kHz After ultrasonic treatment for 10 to 1000 minutes, react at 20 to 200°C for 1 to 20 hours, suction filter, wash, and vacuum dry at 0 to 180°C to obtain carbon nanotubes with initiator groups on the surface; Step (e): adding 0.01-1 parts by weight of catalyst, 0.01-5 parts by weight of ligand, and then adding 1 part by weight of carbon nanotubes with initiating groups on the surface obtained in step (d), and 10-50 parts by weight of solvent, After sealing, fill with Ar or N ₂ for 1 to 100 minutes, add 0.01 to 80 parts by weight of p-chloromethylstyrene monomer, continue to fill with nitrogen or argon for 1 to 100 minutes, and react at 0 to 150°C for 0.01 to 1000 hours. Stop the reaction, add solvent to dilute, filter with suction, wash, and dry in vacuum at 0-180°C to obtain carbon nanotubes grafted with hyperbranched poly-p-chloromethylstyrene with a degree of polymerization of 5-1000. The polymer structure is as shown in the figure below:

2. the preparation method of the carbon nanotube of hyperbranched poly-p-chloromethylstyrene grafting according to claim 1 is characterized in that the carbon nanotube used in step (a) has catalytic pyrolysis, arc discharge, template Single-walled or multi-walled carbon nanotubes prepared by laser evaporation method. 3. the preparation method of the carbon nanotube grafted by hyperbranched poly-p-chloromethylstyrene according to claim 1 is characterized in that the used strong oxidizing acid of step (a) has 0.1～70% weight acid concentration nitric acid, 0.1-100% acid concentration sulfuric acid by weight, 1/100-100/1 molar ratio nitric acid and sulfuric acid mixed solution, 1/100-100/1 molar ratio potassium permanganate and sulfuric acid mixed solution, 1/100-100/1 molar Potassium permanganate and hydrochloric acid mixed solution, 1/100～100/1 molar ratio potassium permanganate and _nitric acid mixed solution, 1/100～100/1 molar ratio _H2O2 and sulfuric acid mixed solution, 1/100～ 100/1 molar ratio H ₂ O ₂ and hydrochloric acid mixed solution or 1/100-100/1 molar ratio H ₂ O ₂ and nitric acid mixed solution. 4. the preparation method of the carbon nanotube of hyperbranched poly-p-chloromethylstyrene graft according to claim 1 is characterized in that used acylating agent has phosphorus trichloride, phosphorus pentachloride, phosphorus pentachloride, Thionyl chloride, phosphorus tribromide, phosphorus pentabromide, or thionyl bromide. 5. the preparation method of the carbon nanotube of hyperbranched poly-p-chloromethylstyrene grafting according to claim 1 is characterized in that the polyhydric alcohol or polyamine substance used in step (c) has ethylene glycol, ethylene glycol Diamine, glycerol, glycerin triamine, 1,2-propanediol, 1,2-propanediamine, 1,3-propanediol, 1,3-propanediamine, 1,4-butanediol, 1,4 -Butanediamine, 1,2-butanediol, 1,2-butanediamine, 1,3-butanediol, 1,3-butanediamine, butanetriol, butanetriamine, polyethylene glycol or Polyethylenediamine. 6. The preparation method of the carbon nanotubes grafted by hyperbranched poly-p-chloromethylstyrene according to claim 1 is characterized in that the α-haloacyl halide used in the step (d) has α-bromobutyryl Bromine, α-bromoisobutyryl bromide, α-bromopropionyl bromide, α-chlorobutyryl chloride, α-chloroisobutyryl chloride or α-chloropropionyl chloride. 7. the preparation method of the carbon nanotube of hyperbranched poly-p-chloromethylstyrene grafting according to claim 1 is characterized in that step (c), (d) do not use solvent or use dimethyl sulfoxide , N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, chloroform, tetrahydrofuran, ethyl acetate, acetone, acetonitrile, butanone, triethylamine, pyridine Or dimethylaminopyridine is a solvent or a mixed solvent containing these solvents is a reaction medium. 8. The preparation method of the carbon nanotubes grafted by hyperbranched poly-p-chloromethylstyrene according to claim 1 is characterized in that the catalyst used in the step (e) contains Cu(I), Fe(II), Metal compounds of Mo(V), Re(V), Ru(II), Ni(I) or Pb(II), including cuprous chloride, cuprous bromide, ferrous chloride, ferrous bromide, Lithium molybdate, bis(triphenylphosphinyl)rhenium iodide oxide, ruthenous chloride, nickel cyanogen bromide or lead acetate; the ligands used are 2-bipyridyl, tetramethylethylenediamine, pentamethyl- Diethyltriamine, hexamethyl-triethylenetetramine, oxalic acid, malonic acid, succinic acid, phthalic acid, triphenylphosphine or tri-n-butylphosphine; the solvent used is dimethyl Sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, chloroform, dichloromethane, dichloroethane, tetrahydrofuran, ethyl acetate, acetone , butanone, acetonitrile, propanol, ethanol, methanol or mixtures containing these solvents. 9. Hyperbranched poly-p-chloromethylstyrene-grafted carbon nanotubes, characterized in that the hyperbranched poly-p-chloromethylstyrene-grafted carbon nanotubes obtained by the preparation method according to claims 1-8.

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