TWI433812B - Novel modified carbon nanotubes and polymer/nanotube material derivatives and preparation methods of the same - Google Patents

Description

Novel modified carbon nanotube and preparation method of polymer/nano carbon tube composite derivative

The present invention relates to a modified carbon nanotube and a method of manufacturing the same. The modified carbon nanotubes can further form a carbon nanotube composite with other polymer substrates.

Carbon nanotubes have unique mechanical, electrical, optoelectronic, and electrical thermal conductivity characteristics, and are regarded as important basic materials for the development of cutting-edge technology in the new generation. However, it is necessary to introduce carbon nanotubes into organic materials to increase their carbon nanotubes. In the original physical properties, it is limited by the aggregation of carbon tubes and the incompatibility with organic materials. Therefore, how to improve the processability of carbon tubes and avoid aggregation is still an important research direction. At present, it is often seen that methods for improving the dispersibility of carbon tubes include ultrasonic vibration, surfactants, and functionalization of the surface of carbon tubes. Among them, chemical surface-based functionalization of carbon tubes is most popular, including (1) A strong acid solution is used to produce a carboxyl group (COOH group) at the end or defect of the carbon tube ^[1] to achieve the purpose of dispersion. However, the disadvantage is that the strong acid will cause defects on the surface of the carbon tube and reduce the excellent electrical conductivity of the carbon tube. (2) The Friedel-Crafts reaction is carried out on the surface of the carbon tube with polyphosphoric acid and phosphorus pentoxide as solvents and catalysts ^[2] . (3) Using the Diels-Alder reaction ^[3-5] to introduce an organic functional group on the carbon tube, the chemical reaction to reform the carbon tube is simple and has low process conditions and does not damage the carbon tube structure. , with industrial feasibility.

[1] Che J., Yuan W., Jiang G., Dai J., Lim S. Y., Chan-Park M. B. Chem. Mater. 2009, 21, 1471.

[2] JEON I.Y., TAN L.S., BAEK J.B.J. Polym. Sci. Part A: Polym. Chem. 2010, 48, 1962.

[3] Zhang L., Yang J., Edwards C.J., Alemany L.B., Khabashesku V.N. and Barron A.R. Chem. Commun. 2005, 3265.

[4] Chang C.M., Liu Y.L. carbon, 2009, 47, 3041.

[5]Munirasu S., Albuerne J., Boschetti-de-Fierro A., Abetz V. macro. raip. comm. Macromol. Rapid Commun. 2010,31,574

Although there have been examples of the modification of carbon tubes by Diels-Yard reaction in the literature, the compounds of the polymaleimide group are modified to form carbon nanotubes to form reactive maleimine functional groups. The carbon nanotubes have never been seen before.

It is an object of the present invention to provide a novel modified carbon nanotube comprising a carbon nanotube and a polymaleimide group.

Another object of the present invention is to provide a method of preparing a modified carbon nanotube by achieving a modified carbon nanotube by a Diels-Alder reaction.

A second object of the present invention is to provide a carbon nanotube composite comprising a modified carbon nanotube and a polymer substrate having good compatibility.

Still another object of the present invention is to provide a method for preparing a carbon nanotube composite material by further reacting a modified carbon tube having a maleic imine functional group with a polymer substrate. According to the present invention, the modified carbon nanotube is represented by the formula (1),

Wherein n = 2 or 3, when n = 2, the Ar system is selected from the group consisting of:

When n = 3, the Ar system is selected from the following groups:

The preferred of the above Ar is:

The method for preparing a modified carbon nanotube in the present invention is a method of combining a carbon nanotube with a compound having a polymaleimide group of the formula (2).

This is achieved by carrying out a Diels-Yard reaction in a solvent at a temperature of 40 to 140 ° C, preferably at a temperature of 50 to 90 ° C, wherein n and Ar are as defined in the preceding paragraph.

In the above method of the present invention, the solvent is N-N-dimethylvinylamine (DMAc) or dimethylammonium (DMSO).

The above process of the present invention is preferably carried out in a gas atmosphere such as nitrogen or air for 12 to 150 hours, preferably for 70 to 120 hours.

The invention also provides a novel carbon nanotube composite material comprising a modified carbon nanotube and a polymer substrate with good compatibility, which utilizes a carbon tube having a maleic imine functional group, and a polymer The substrate is further reacted. in particular:

(1) A modified carbon nanotube having a maleimide functional group capable of reacting with a cyanate ester to form a Bismaleimide-Triazine (BT) bond Forming a polyisocyanate/nanocarbon tube composite with good compatibility.

(2) A modified carbon nanotube having a maleimide functional group, which can be subjected to a Michael addition reaction with an amino group or a mercapto to form a covalent bond. . For example, a modified carbon nanotube having a maleimide functional group is added to a solution of a dianhydride and a bisamine for polymerization because the amine group undergoes a Michael addition reaction with the maleimine functional group to form A well-compatible polyimide/nanocarbon tube composite.

(3) A modified carbon nanotube having a maleimide functional group, which is added to an epoxy resin and a diamine hardener for polymerization because the amine group undergoes a Michael addition reaction with the maleimide functional group. It can form a good compatibility epoxy/nanocarbon tube composite.

(4) A modified carbon nanotube having a maleimine functional group, which is reactive with a silane coupling agent having an amine group or a thiol group, and the modified carbon nanotube is The oxirane coupling agent is bonded to form a siloxane/nanocarbon tube composite.

The general synthetic method of the present invention first selects a solvent which has good solubility to the polymaleimide functional group compound, dissolves the polymaleimide functional group compound in a solvent, and adds single-wall or multi-walled nanometer. After the carbon tube is reacted in a nitrogen atmosphere at a temperature of 50 to 90 ° C, the product is preferably washed in a suitable solution such as tetrahydrofuran, filtered, and dried.

The following examples are intended to further illustrate the invention and are not intended to limit the scope of the invention. For example, other aromatic maleimides may also be used to produce modified carbon nanotubes having different structures via similar reactions. Any modifications and variations which may be made without departing from the spirit of the invention are intended to be within the scope of the invention.

Example 1: Method for producing a carbon nanotube having a maleimide functional group

As shown in Fig. 1, it is a reaction equation of a modified carbon nanotube of 4,4'-dimaleimide diphenylmethane (4,4'-Bismaleimidodiphenylmethane).

In accordance with the present invention, 0.25 grams of 4,4'-dimaleimido diphenylmethane, 0.05 grams of carbon nanotubes, and 15 milliliters of dimethylacetamide (DMAc) were placed in a three-necked reaction flask. The reaction was stirred under a nitrogen atmosphere at 50 ° C for 96 hours, and the product was poured into a tetrahydrofuran (THF) solution for several times, and then filtered and dried.

Figure 2 is an IR diagram of the carbon nanotubes before and after the modification. It can be observed that the C=O (1708 cm ^-1 ) and CNC (1548 cm ^-1 ) maleimine structures appear on the modified carbon nanotubes. The characteristic peak on the surface proves that the carbon tube has been successfully upgraded.

Figure 3 is a longitudinal modified carbon nanotube of FIG Raman, it can be observed from the figure after the modification is located 1333cm ^-1 sp signal representative of the peak (D band) ³ 1588cm ^-1 and the peak ² is representative of the signal sp (G The ratio of band) is much more than that of the carbon tube before the modification, which indicates that the carbon tube has been upgraded successfully.

Figure 4 is a TGA diagram of the carbon nanotubes before and after the modification. It can be clearly observed that the unmodified carbon tubes have almost no loss of thermogravimetry at 800 °C; otherwise, the modified carbon nanotubes are at about 500 ° C and There is a significant loss of thermogravimetry, indicating that the cracking of maleimide is included, and the final residual ratio differs from that of the pre-modified carbon nanotube by about 9%.

Fig. 5 shows that the modified carbon nanotubes were placed in a solvent for dispersibility test for 30 days, and it was observed that the modified carbon tubes were well dispersed in dimethyl hydrazine, tetrahydrofuran and ethanol solvents after the modification.

Example 2: Preparation of polycyanate/nanocarbon tube composite

The modified carbon nanotubes with the maleimide functional group at the modified end are added to the cyanate ester at a ratio of 0.5 phr, 1.0 phr and 1.5 phr, respectively, and uniformly mixed, at 200, 220, The temperature was raised at 240 and 260 ° C for cross-linking reaction to further form a BT resin carbon nanotube composite.

Figure 6 is a DMA graph of the BT resin carbon nanotube composite. The introduction of the carbon nanotubes still maintains the high storage modulus and glass transition temperature of the resin. This result indicates that the introduction of the modified carbon nanotubes does not break. The original properties of the resin.

Fig. 7 is a TGA curve diagram of the BT resin carbon nanotube material. After adding the modified carbon nanotube, the thermal stability of the resin is effectively improved, and the cracking temperature is improved and the residual rate is obviously observed.

Example 3: Preparation of Polyimine/Nano Carbon Tube Composites

The polyimine/nanocarbon tube composite is prepared by adding 0.5002 g (2.5 mmol) of 4-4'-diaminodiphenyl ether and N into a three-neck reaction flask through which nitrogen is passed. - Methylrrolidone (NMP) 7.1983 g is configured to have a solids content of 15% by weight. After complete dissolution, 0.7701 g (2.5 mmol) of 4-4'-oxydiphthalic anhydride (4,4') is added. -oxydiphthalic anhydride) forms polyamic acid; at this time, 0.02 g (1.5 phr) of modified carbon nanotubes are added, uniformly mixed and coated on a glass substrate at 100, 200, 300 ° C Each hour, a dehydration ring closure and a Michael addition reaction between the amine group and the maleimide were carried out to form a polyimide/nanocarbon tube composite. The TGA stability analysis shows that the polyimide/nanocarbon nanotube composite maintains excellent thermal stability and is also higher in residual ratio than pure polyimine.

Example 4: Preparation of epoxy resin/nanocarbon tube composite

The epoxy resin/nanocarbon tube composite is prepared by the equivalent of 4,4'-diaminodiphenylmethane (DDM) and epoxy resin DGEBA (EEW=188). Premixed, add 1.5 phr of modified carbon nanotubes and stir them evenly, then heat-treat the epoxy resin at 180, 200, 220 °C and the wheat between the amine group and the maleimide The addition reaction forms an epoxy/nanocarbon tube composite. In terms of properties, it was found that the glass transition temperature was increased from 187 ° C to 195 ° C; the cracking temperature and residual rate were significantly improved in the thermal stability test.

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

Figure 1 is a flow chart of the modification of the carbon nanotubes.

Figure 2 is an IR diagram of the carbon nanotubes before and after upgrading.

Figure 3 is a Raman diagram of the carbon nanotubes before and after upgrading.

Figure 4 is a TGA diagram of the carbon nanotubes before and after upgrading.

Figure 5 is a modified carbon nanotube dispersion test.

Figure 6 is a DMA diagram of a BT resin carbon nanotube composite.

Figure 7 is a TGA diagram of a BT resin carbon nanotube composite.

(no component symbol description)

Claims (16)

a modified carbon nanotube such as the general formula (1), Wherein n = 2, the Ar system is selected from the group consisting of: The modified carbon nanotube of claim 1, wherein Ar is . A method for preparing a modified carbon nanotube according to claim 1, which comprises a carbon nanotube and a compound having a polymaleimide group of the formula (2) The Diels-Alder reaction is carried out in a solvent at a temperature of 40 to 140 ° C, wherein n and Ar are as defined in claim 1. The method of claim 3, wherein the solvent is N-N'-dimethylacetamide or dimethylammonium. The method of claim 3, wherein the reaction temperature is from 50 to 90 °C. The method of claim 3, which is carried out in a gas atmosphere such as nitrogen or air for 70 to 120 hours. A carbon nanotube composite comprising the modified carbon nanotube of claim 1 and a reaction with a compound of the formula (2) having a polymaleimide group as described in claim 3 Molecular substrate. The carbon nanotube composite material of claim 7, wherein the polymer substrate is a polycyanate. The carbon nanotube composite material of claim 7, wherein the polymer substrate is polyimine. The carbon nanotube composite material of claim 7, wherein the polymer substrate is an epoxy resin. A siloxane/nanocarbon tube composite comprising the modification of claim 1 A carbon nanotube and an amine or thiol group-containing oxirane coupling agent bonded thereto. A method of preparing a carbon nanotube composite material according to claim 7, which is carried out by reacting a modified carbon nanotube having a maleic imine functional group with a polymer substrate. The method of claim 12, wherein the polymeric substrate is a polycyanate. The method of claim 12, wherein the polymeric substrate is polyimine. The method of claim 12, wherein the polymeric substrate is an epoxy resin. A method for preparing a siloxane/nanocarbon nanotube composite material by reacting a modified carbon nanotube of claim 1 with an amine or thiol group-containing oxirane coupling agent.