KR101436367B1 - Cellulose magnet produced by solvothermal method and method for producing the same - Google Patents

Abstract

Disclosed is a cellulose magnet produced by a solvothermal method and a producing method thereof. The cellulose magnet is produced by heating a reactor in which cellulose powder and a solvent are inserted and by the solvothermal method. According to the present invention, the cellulose magnet can be produced at relatively low temperature and pressure by using the solvothermal method. Properties of the cellulose magnet can be adjusted according to a solvothermal treatment period.

Description

[0001] The present invention relates to a cellulose magnet produced by a solvent heating method and a method for producing the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon magnet and a manufacturing method thereof, and more particularly, to a cellulose magnet and a manufacturing method thereof.

Carbon is the most basic element that forms the basis of organics and biomaterials and has played a crucial role in human history development and modern science and technology development. The existence of solid carbon is a typical example of diamond and graphite. However, after the discovery of fullerene (C60), research on carbon materials such as carbon nano tube (CNT) and graphene is also active. In the past, studies on the mechanical and electrical properties of carbon materials have been mainly carried out, but in recent years, studies on carbon materials as magnetic and light emitting materials have also become issues.

Since the report of the room temperature ferromagnetism of fullerene polymers formed at high temperature and high pressure in 2001, new carbon magnet research has been carried out steadily as the interest in carbon magnets including fullerene magnets has been explosively increased. Previously, low temperature (10 K) and room temperature (300 K) ferromagnetism have been reported in specimens treated with high temperature (1200 ° C) and high pressure (5 GPa) of powdered glassy carbon using a special high pressure device have. However, this technology requires considerably high temperature and high pressure processing conditions using special high pressure equipment.

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a carbon magnet at a relatively low temperature and a low pressure in place of a known high temperature and high pressure treatment method, and a carbon magnet manufactured by the method.

In order to accomplish the above object, the present invention provides a cellulose magnet and a method of manufacturing the same.

The cellulose magnet according to the present invention is produced by a solvothermal method by heat treating a mixed solution of a cellulose powder and a solvent.

According to an aspect of the present invention, there is provided a method for manufacturing a cellulose magnet, comprising: preparing a mixed solution by mixing a cellulose powder and a solvent; And heat treating the mixed solution.

According to the present invention, a cellulose magnet can be produced by using a solvent heating method. The method according to the present invention can replace the treatment method of high temperature and high pressure, which are known to make carbon magnets, and at the same time, the cellulose magnets can be manufactured relatively easily at a low temperature and a low pressure and the characteristics of the cellulose magnets can be controlled have.

According to the present invention, ferromagnetic cellulose can be obtained by a relatively simple solvent heating method. Therefore, the manufacturing process of the cellulose magnet can be simplified and the cost can be reduced, which is more advantageous for mass production.

1 is a view showing the structure of cellulose.
2 is a SEM image showing the morphology of cellulose.
3 is a graph showing the low temperature (measured at 5 K) magnetic moment measured in a cellulose virgin sample according to the experimental example of the present invention as a function of the magnetic field.
FIG. 4 is a graph showing a low temperature (5K) magnetic moment measured in cellulose subjected to heat treatment of an ethanol solvent for 7 days according to the experimental example of the present invention as a function of the magnetic field.

Hereinafter, preferred embodiments of a cellulose magnet according to the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is provided to let you know.

Cellulose is a kind of polymer polysaccharide and is a polymer compound in which β-D-glucose is bound in a straight chain form with β-glucosidic bonds (1-4 glucosidic bonds). Cellulose in a pure state has a luminescent optical property but a diamagnetic magnetic property. Cellulose is expected to have similar properties to glucose and carbon because it is a bonding structure in which several glucoses are bound and carbon is embedded between them, but there is no clear evidence.

1 is a view showing the structure of cellulose. Cellulose has a molecular structure as shown in FIG. 1 (a), that is, ((C ₆ H ₁₀ O ₅ ) _n ) and has a molecular structure as shown in FIG. 1 (b). As shown in Fig. 1, cellulose is composed of a complex of various saccharides. Cellulose is a white, odorless solid and does not dissolve in water. It is very strong in alkali but hydrolyzed in acid to become glucose.

To prepare the cellulose magnets according to the present invention, a mixed solution is first prepared by mixing a cellulose powder and a solvent, and then the mixed solution is heat-treated.

Specifically, the cellulose powder can be prepared by purchasing a commercially available product. The solvent is selected so as to be capable of dispersing cellulose and effectively transfer heat energy to cellulose by heating. Preferably, the solvent is ethanol.

The mixing ratio of the cellulose powder and the solvent can be appropriately adjusted. When the solvent is ethanol, the amount of the ethanol may be 20 ml per 0.5 g of the cellulose powder. At this mixing ratio, the mixed solution is a viscous, fluid liquid.

The mixed solution prepared by mixing the cellulose powder and the solvent may be heat-treated in a general reactor. The reactor used here may be a pressure vessel such as a vacuum hermetic Teflon vessel, but since it is not necessary to have a high-pressure condition, it may be a general application, not a pressure vessel. For example, a simple container having a lid on a crucible may be used.

The heating of the mixed solution can be performed at a relatively low temperature, for example, 30 to 300 DEG C, and preferably 180 DEG C if the solvent is ethanol. When the pressure vessel is not used at a temperature of 30 to 300 ° C, the pressure in the reactor becomes about a few MPa, and there is no need for a separate pressurization process, and the pressure is relatively low.

If the heating temperature is lower than 30 ° C, the time for changing the molecular structure of the cellulose is increased so as to increase the magnetic property, and there is a problem in mass production. When the temperature is higher than 300 ° C, the time is shortened. . The heat treatment can be carried out for more than one day. If the reaction time is too short, it is difficult to obtain sufficient magnetism. If the reaction time is too long, the efficiency of the process is deteriorated. If necessary, the mixed solution may be stirred, but it may be selectively stirred only during a certain period of the reaction (initial reaction).

<Experimental Example>

Commercially available cellulosic powder was purchased. Then, 0.5 g of cellulose powder was mixed with 20 ml of ethanol and placed in a cell having a diameter of 7 cm and a thickness of 3 cm, followed by solvent heat treatment at 180 ° C for a period of time. Distilled water was also used for comparison with the case of using ethanol as a solvent. The cellulose powder used was? -Cellulose (trade name: C8002, density: 0.600 g / cm ³ ) of Sigma Aldrich Co.

2 is a SEM image showing the morphology of cellulose. Cellulosic powders have a circular grain shape and do not have an anisotropic structure like fibers, so they exhibit a behavior different from that of fibers.

Table 1 is a table showing kinds, amount, added temperature and solvent heat treatment period of the solvent mixed with the cellulose powder.

Referring to Table 1, an experiment for practicing the present invention performed solvent heat treatment for a period of time having characteristics of the checked area. That is, solvent heat treatment was performed while changing the treatment time to 1 day, 3 days, 5 days, and 7 days with a virgin sample containing 0.5 g of cellulose powder and 20 ml of ethanol. For comparison with the case of using ethanol as a solvent, a case in which distilled water was used, that is, a virgin sample in which 0.5 g of cellulose powder and 20 ml of distilled water were mixed was subjected to treatment for 1 day, 3 days, 5 days, Treatment.

One day treatment was obtained in a liquid state with a higher concentration than a virgin sample, and a powder state was obtained after 2 days treatment.

FIG. 3 is a graph showing the low temperature (measured at 5 K) magnetic moments measured by a cellulose virgin sample according to the experimental example of the present invention as a function of the magnetic field. Cellulose does not become magnetized in the virgin state without any treatment.

As shown in Table 1, when the samples were heated at a low temperature (5 K) after 7 days heat treatment of the ethanol solvent, the largest magnetic property was observed as follows. No magnetism was observed in the experimental example of other conditions.

FIG. 4 is a graph showing a low temperature (5K) magnetic moment measured in cellulose subjected to heat treatment of an ethanol solvent for 7 days according to the experimental example of the present invention as a function of the magnetic field.

Referring to FIG. 4, after the solvent heating method, the magnetic moment is rapidly saturated with the increase of the magnetic field, which is evidence that the cellulose molecule is ferromagnetic. That is, a cellulose magnet is formed by a solvent heating method. The cell magnet according to the present invention was measured to have Hc of about 100 G and Ms of about 0.0005 emu / g. It was also found that, even after the magnetism measurement was performed after a few months, the magnetism was kept as it is, and the change with time was small.

According to the present invention, the cellulose magnets can be produced under the heating conditions of about 180 ° C without the necessity of the high temperature and high pressure conditions through the solvent heating method. It is a great discovery that cellulose magnets can be produced by making the structure magnetized like sp3 without needing to graphitize the cellulose as a whole when the solvent heat transfer method, that is, the heat energy by heating through the solvent, is effectively transferred to the cellulose.

As described above, the method of producing cellulose by the solvent heating method is a remarkably modified high-temperature and high-pressure condition, and is suitable for mass production of cellulose magnets at low cost without expensive equipments such as pressure vessel and pressure device .

Compared to other magnetic materials, carbon-based magnets are more stable, easy to realize functionalization and industrialization, lightweight, non-toxic, easy to develop and cheap. Therefore, the carbon magnet according to the present invention is expected to provide new development possibilities in the fields of green, environment-friendly industry, and biomedicine. In particular, cellulose is an organic compound that exists in large quantities following coal in nature, and is an industrially important resource. Cellulose is much cheaper than conventional carbon materials such as CNT, so it is cost competitive when manufacturing magnets.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation in the embodiment in which said invention is directed. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the appended claims.

Claims (6)

A cellulose magnet according to a solvent heating method, characterized in that it is produced by a solvent heating method by heat treating a reactor containing a cellulose powder and a solvent. The method according to claim 1,
Wherein the solvent is ethanol. The method according to claim 1,
Wherein the heat treatment is performed at 180 DEG C for 7 days. Placing a cellulose powder and a solvent in a reactor; And
And heat treating the reactor. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 5. The method of claim 4,
Wherein the solvent is ethanol. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; 5. The method of claim 4,
Wherein the heat treatment is performed at 180 DEG C for 7 days. &Lt; RTI ID = 0.0 &gt; 15. &lt; / RTI &gt;

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