KR20040077342A - Polystyrene-polypentylmethacrylate block copolymer, temperature sensor and pressure sensor using the same - Google Patents

Abstract

The block copolymer according to the present invention forms a nanostructure only at a specific temperature or a specific pressure, it is possible to adjust the range of the temperature region and the pressure region according to the control of the number average molecular weight. When the block copolymer has a nanostructure, the scattering intensity of the polarized light is changed, and the modulus and viscosity of physical properties are rapidly increased. Therefore, it can be used not only as a temperature sensor due to changes in optical properties or processes requiring nanostructure at a specific temperature, but also as a pressure sensor.

Description

Polystyrene-polypentylmethacrylate block copolymer, temperature sensor and pressure sensor using the same

The present invention relates to a polystyrene-polypentyl methacrylate block copolymer, and more particularly, to a block copolymer capable of arbitrarily controlling physical and optical properties by forming nanostructures in a specific temperature and pressure region, and a temperature sensor using the same. And a pressure sensor.

In addition to the rapid development of information storage media, free control of nanopatterns is essential for the production of terabit-class storage media and for the production of templates ranging from a few nanometers to tens of nanometers. Therefore, attempts have been made to use the storage media by forming nanopatterns using polymers.

Block copolymers having a critical molecular weight or more take the form of nanostructures when the temperature is reduced in the molten state, which is the same in the block copolymers as phase separation occurs without mixing with each other when the incompatible polymers are blended. This is due to the fact that fine phase separation occurs as the temperature of the incompatible components in the copolymer block decreases. However, since the incompatible components in the block copolymer are linked by covalent bonds, as the above fine phase separation occurs, the respective chains are greatly elongated and thus the entropy is reduced rather than the random state. As a result, the fine phase separation proceeds, and as the size of each domain increases, the enthalpy decreases but the entropy also decreases. Will have the minimum value. Such a domain is called a microphase domain, and its size is in the order of several tens of nanometers, and has various types of microphases (nanostructure, hereinafter referred to as nanostructure) such as lamellar, cylinder, or sphere. The phenomenon in which the block copolymer is transferred from the homogeneous phase to the nanostructure by reducing the temperature is called a microphase seperation transition, and the temperature at which the temperature causes the microphase structure transition, or the uniform-uniform transition temperature ( order-disorder transition temperature (TODT).

However, most molten block copolymers form nanostructures only above the critical molecular weight and the nanostructures disappear when the temperature is higher than TODT. Therefore, the molecular weight must be increased in order to maintain the nanostructure even at high temperature, but when the molecular weight is increased, the mobility decreases rapidly, which makes it difficult to form a regular nanostructure.

On the other hand, in contrast to the above, the fact that the block copolymer composed of polystyrene and polybutyl methacrylate shows uniform physical properties of a single polymer in a low temperature molten state, but when the temperature is raised above a certain temperature, a nanostructure is formed. Found. However, even in this case, only two phases of the homogeneous phase and the nanostructure are generated according to the temperature change, and thus, there is a disadvantage in that the application is poor because the nanostructure cannot be provided only at a specific temperature or a specific pressure.

Therefore, the first technical problem to be achieved by the present invention is to solve the problems of the prior art to form a nanostructure only in the temperature and pressure region required as needed to provide a wide range of block copolymer applications.

The second technical problem to be achieved by the present invention is to provide a temperature sensor using the block copolymer.

The third technical problem to be achieved by the present invention is to provide a pressure sensor using the block copolymer.

Figure 1 shows the dependence of the upper limit and the lower limit of the optimum number average molecular weight as the x value of the block copolymer according to the present invention.

Figure 2 shows the change in modulus according to the temperature of the block copolymer prepared by Examples 1 to 5 and Comparative Examples 1 and 2 of the present invention.

Figure 3 shows the change of modulus with the temperature of the block copolymer prepared by Examples 6 to 8 of the present invention.

Figure 4 shows the change in the scattering intensity of light with the temperature of the block copolymer prepared by Example 4 of the present invention.

Figure 5 shows the change in physical properties with the pressure of the block copolymer prepared by Example 9 of the present invention.

The present invention to solve the first technical problem

It provides a polystyrene-polypentyl methacrylate block copolymer of Formula 1 to form a nanostructure only in a specific temperature or pressure region.

(Wherein x and y are 0.15 ≦ x ≦ 0.85 as volume fraction and x + y = 1).

According to one embodiment of the present invention, the polystyrene-polypentyl methacrylate block copolymer is a polystyrene-polypentyl methacrylate block copolymer, characterized in that the number (M) satisfies the following formula (1).

[Equation 1]

938572x ² -938572x + 27836≤number average molecular weight (M) ≤1036190x ² -1036190x + 306495

(Wherein x is a volume fraction of styrene)

Further, the number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is preferably 46,000 to 50,000 when x is 0.5.

The number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is preferably 79,000 to 87,000 when x is 0.3.

Further, the number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is preferably 159,000 to 175,000 when x is 0.15.

According to another embodiment of the present invention, the polystyrene-polypentyl methacrylate block copolymer is preferably prepared by blending two or more block copolymers of Formula 1 having different number average molecular weights.

In addition, the polystyrene-polypentyl methacrylate block copolymer is preferably prepared by blending two or more block copolymers of the formula 1, the volume fraction of the monomers.

According to a preferred embodiment of the present invention, the polystyrene-polypentyl methacrylate block copolymer is preferably prepared by an anionic polymerization method.

The present invention provides a temperature sensor using the polystyrene-polypentyl methacrylate block copolymer in order to achieve the second technical problem.

The present invention provides a pressure sensor using the polystyrene-polypentyl methacrylate block copolymer to achieve the third technical problem.

Hereinafter, the present invention will be described in more detail.

The block copolymer according to the present invention is characterized in that the block copolymer made of polystyrene and polypentyl methacrylate. In Formula 1, x and y represent the volume fraction of each monomer, and nanostructures of various forms can be obtained according to the control of the x value. As x increases, spherical, cylindrical, and lamellar structures of polystyrene are obtained. As x is increased more than 0.5, it is changed into a cylindrical structure and a spherical structure of polypentyl methacrylate which is reversed. Generally, when the volume fraction of one block of the block copolymer is f, when f is less than 0.25, it has a spherical structure, when 0.25 f 0.4 has a cylindrical structure, and when it is 0.4 f 0.5, it has a lamellar structure. On the other hand, when f exceeds 0.5, it becomes the form which has the microstructure of the other block. Accordingly, in the block copolymer according to the present invention, x may range from 0.01 to 0.99, and such various nanostructures may have different physical and optical properties such as modulus, viscosity, and the like, depending on their shape. By varying the value of x, the shape of the nanostructure can be arbitrarily adjusted, thereby extending its application.

The number average molecular weight (M) of the block copolymer according to the present invention is characterized by satisfying the following formula.

938572x ² -938572x + 27836≤number average molecular weight (M) ≤1036190x ² -1036190x + 306495

(Wherein x is a volume fraction of styrene)

That is, the block copolymer according to the present invention is characterized in that it has a nanostructure in a specific temperature and pressure region, which has a characteristic that depends on the x value and the number average molecular weight. That is, when the x value is 0.5, the number average molecular weight is preferably in the range of 46,000 to 50,000, but when it is less than 46,000, no nanostructure is formed, and when it exceeds 50,000, the nanostructure is formed at all temperature ranges. This is because there is no change in physical properties with temperature or pressure, which is undesirable. The block copolymer according to the present invention can narrow or widen the temperature range where the nanostructure is formed by controlling the number average molecular weight according to x value within the above range. For the same reason as described above, the number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is preferably 79,000 to 87,000 when x is 0.3 and 159,000 to 175,000 when x is 0.15.

On the other hand, the block copolymer according to the present invention, for example, when x is 0.5 can be made only of the block copolymer having a number average molecular weight of 46,000 to 50,000 alone, the block copolymer having a number average molecular weight of 46,000 or less and the number average molecular weight It may be a blend polymer prepared by blending a block copolymer of 50,000 or more to a total number molecular weight of 46,000 to 50,000. The advantage of such blend polymers is that by mixing two block copolymers with different number average molecular weights, it is easy to control them to form nanostructures only at certain temperatures and pressures.

In addition, the block copolymer according to the present invention may be prepared by blending block copolymers having different volume fractions. In this case, as mentioned above, there is an advantage that the physical property of the overall block copolymer is easily controlled.

The block copolymer according to the present invention can also be produced by radical polymerization, but it is preferable to use anionic polymerization in terms of controlling the manufacturing process, manufacturing cost and number average molecular weight. When prepared by the anionic polymerization method, as mentioned above, not only the number average molecular weight can be easily controlled, but also the number average molecular weight is nearly uniform, so that the two or more block copolymers having different number average molecular weights are different. It is easy to calculate the overall number average molecular weight when blending, it is possible to predict the physical characteristics of the blend polymer in advance.

On the other hand, the temperature sensor using the block copolymer according to the present invention can be manufactured in the form of a thin film, it is possible to simplify additional devices, it is characterized in that it operates only in a specific temperature range. In other words, not only the scattering intensity due to modulus, viscosity or birefringence changes rapidly in a specific temperature range set by controlling the number average molecular weight of the block copolymer, but the nanostructure is spherical, cylindrical or lamellar. Since the physical characteristics also change depending on whether or not the recognition, the process can be smoothly controlled by detecting when the temperature is out of the region to be performed in a specific temperature region.

In addition, the block copolymer according to the present invention can also be used as a pressure sensor, but has a nanostructure up to a certain pressure in a certain temperature range, but when it exceeds a certain pressure it becomes a homogeneous phase, as described above, so that the modulus, viscosity or scattering strength It can change drastically and can be used to sense a certain pressure at a certain temperature.

The polystyrene-polybutyl methacrylate copolymer according to the present invention first initiates the reaction by using a strong base in the styrene monomer, and after a certain time, the butyl methacrylate monomer is mixed. N-butyllithium is mainly used as the strong base initiator, but sodium or potassium strong bases may also be used. Although tetrahydrofuran (THF) is common as a solvent used at the time of preparation, toluene, benzene, ether, etc. can also be used besides this. The reaction is stopped using purified methanol or isopropyl alcohol, and slowly added dropwise while stirring to a solvent mixed with methanol and water to obtain a precipitate. The powder thus obtained is dried under vacuum at 60 to obtain the final product.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments of the present invention, but the present invention is not limited thereto.

Example 1

The monomer styrene was first removed with calcium hydroxide, followed by vacuum distillation, followed by secondary purification with dibutylmagnesium. The second monomer, pentyl methacrylate, was also first removed with calcium hydroxide, followed by vacuum distillation to give triethylaluminum 2 Tea was purified. Tetrahydrofuran was used as a reaction solvent, and purified through a column consisting of activated alumina to remove traces of water or oxygen, and then 300 ml of the solvent was placed in a reactor and maintained at -78 ° C. Next, 0.435 ml of 1-mole sec-butyllithium dissolved in cyclohexane and 0.3 g of dried lithium chloride as a polymerization initiator were mixed in the solvent. Thereafter, 10 g of purified styrene was added, and after a sufficient time of about 1 hour, 10 g of pentyl methacrylate was added. For about 5 hours after the second monomer was added for complete conversion, the reaction was stopped using 1 ml of purified methanol. Next, after slowly raising the temperature of the reaction vessel to room temperature, methanol and water were added dropwise while stirring to an 80/20 (volume ratio) mixed solvent to obtain a precipitate. The precipitate was filtered and then the solvent was removed in vacuo and then gradually heated to 60 ° C. to remove residual solvent to obtain 20 g of a polystyrene-polypentylmethacrylate block copolymer having x = 0.5 and a number average molecular weight of 46,000.

Example 2

A polystyrene-polypentylmethacrylate block having x = 0.5 and a number average molecular weight of 50,000 in the same manner as in Example 1 except that 0.400 ml of 1 mole concentration of sec-butyllithium dissolved in cyclohexane was used as a polymerization initiator. 20 g of copolymer was prepared.

Example 3

0.50 g of the block copolymer having a number average molecular weight of 46,000 obtained in Example 1 and 0.5 g of the block copolymer having a number average molecular weight of 50,000 obtained in Example 2 were blended to obtain a blend weight ratio of 50/50 and a number average molecular weight of 48,000. Blend polymers were prepared.

Example 4

A blend weight ratio of 25/75 is obtained by blending 0.25 g of the block copolymer having a number average molecular weight of 46,000 obtained in Example 1 and 0.75 g of the block copolymer having a number average molecular weight of 50,000 obtained in Example 2, wherein the number average molecular weight is 49,000. Blend polymers were prepared.

Example 5

In the same manner as in Example 1, except that 0.488 ml of 1-mole sec-butyllithium, 8 g of purified styrene and 12 g of pentyl methacrylate dissolved in cyclohexane were used as a polymerization initiator, x = 0.4 and a number average. (20) g of polystyrene-polypentyl methacrylate block copolymer having a molecular weight of 41,000 was obtained. Next, x = 0.6 in the same manner as in Example 1, except that 0.333 ml of 1 mol sec-butyllithium, 12 g of purified styrene and 8 g of pentyl methacrylate dissolved in cyclohexane were used as polymerization initiators. 20 g of polystyrene-polypentyl methacrylate block copolymer having a number average molecular weight of 60,000 was obtained. Then, the block copolymer was blended to prepare a blend polymer having a blend weight ratio of 50/50, x = 0.5, and a number average molecular weight of 49,000.

Example 6

In the same manner as in Example 1, except that 0.120 ml of 1 mole sec-butyllithium dissolved in cyclohexane, 17 g of purified styrene, and 17 g of pentyl methacrylate were used as polymerization initiators. 20 g of a polystyrene-polypentyl methacrylate block copolymer having a molecular weight of 167,000 was obtained.

Example 7

In the same manner as in Example 1, except that 0.120 ml of 1-mole sec-butyllithium, 17 g of purified styrene and 3 g of pentyl methacrylate dissolved in cyclohexane were used as a polymerization initiator, x = 0.85 and a number average. 20 g of a polystyrene-polypentyl methacrylate block copolymer having a molecular weight of 167,000 was obtained.

Example 8

0.240 ml of 1 mole sec-butyllithium dissolved in cyclohexane as a polymerization initiator. 20 g of a polystyrene-polypentyl methacrylate block copolymer having x = 0.3 and a number average molecular weight of 83,000 was obtained in the same manner as in Example 1, except that 6 g of purified styrene and 14 g of pentyl methacrylate were used.

Example 9

In the same manner as in Example 1, except that 0.400 ml of 1-mole sec-butyllithium dissolved in cyclohexane was used as a polymerization initiator, and 10 g of styrene substituted with neutron and 10 g of pentyl methacrylate was used instead of styrene. 20 g of a polystyrene-polypentyl methacrylate block copolymer substituted with a neutron having a number average molecular weight of 50,000 and x = 0.5 was obtained.

Comparative Example 1

In the same manner as in Example 1, except that 0.444 ml of 1-mole sec-butyllithium, 10 g of purified styrene and 10 g of pentyl methacrylate dissolved in cyclohexane were used as the polymerization initiator, x = 0.5 and a number average molecular weight. 20 g of this 45,000 polystyrene-polypentyl methacrylate block copolymer were obtained.

Comparative Example 2

In the same manner as in Example 1, except that 0.385 ml of 1-mole sec-butyllithium dissolved in cyclohexane, 10 g of purified styrene, and 10 g of pentyl methacrylate were used as polymerization initiators, x = 0.5 and a number average molecular weight. 20 g of this 52,000 polystyrene-polypentyl methacrylate block copolymer were obtained.

Test Example 1

Measurement of storage modulus according to temperature

Storage modulus according to temperature is measured and shown in FIGS. 2 and 3.

The degree of dispersion of the block copolymers according to Examples 1 to 8 and Comparative Examples 1 and 2 of the present invention was all 1.03, which was almost a value.

As shown in FIG. 2, since the block copolymer of Comparative Example 1 does not reach the critical number average molecular weight, no nanostructure is formed in the entire temperature range, and as the temperature is increased, the modulus decreases to increase the flowability. . In addition, in the case of Comparative Example 2 exceeding the critical number average molecular weight to form a nanostructure in the entire temperature range, there is only a slight gradual change according to the temperature change does not show a large change. However, in the case of the block copolymer prepared according to Examples 1 to 8 of the present invention, since the nanostructures are formed in a certain temperature range, there is a region where the modulus increases rapidly. In other words, in the case of Example 2, the flowability increases with increasing temperature, and the modulus initially decreases, but the modulus rapidly increases around 140 ° C, which means that the nanostructure is formed, and the nanostructure formed thereafter is about Disappears around 220 ° C. This can be seen by the fact that the modulus decreases sharply above this temperature. On the other hand, in the case of Examples 3 and 4, each of the polystyrene-polypentyl methacrylate block copolymer prepared and then blended to show the data for the blended polymer in which the number average molecular weight was adjusted in the range of 47,000 to 50,000. It can be seen that by simply adjusting the number average molecular weight by blending, the temperature range for forming the nanostructure can be narrowed or widened. In addition, the polymer according to Example 5, although the volume fraction of the monomer of the copolymer to be blended differs from 0.4 and 0.6, by blending it, the overall volume fraction corresponds to the average value of 0.5 and the number average molecular weight corresponds to 49,000. Although, it can be seen that the same physical properties of the polymer according to the present invention.

Meanwhile, in Examples 1 to 5, x = 0.5 corresponds to a lamellar structure. However, in Example 6 shown in FIG. 3, since x is 0.15, it corresponds to a spherical structure. In Example 7, x is Since 0.85, it corresponds to the spherical structure of the polypentyl methacrylate, which is the opposite block, and in the case of Example 8 has a cylinder structure because x is 0.3. The nanostructures (microstructures) of such molten block copolymers include small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS), and transmission electron microscopy ( This can be determined by an appropriate combination of transmission electron microscopy (TEM). In conclusion, it can be seen that the modulus increases rapidly in a specific temperature region regardless of the shape of the nanostructure. On the other hand, as shown in Figure 3 it can be seen that the temperature range of the nanostructure changes as the x value is changed. That is, in Examples 6 and 7, the block copolymer according to the present invention rapidly increases modulus around about 180 ° C, and the nanostructure formed at this time disappears around about 250 ° C. As such, since the physical properties of the nanostructure are rapidly changed while controlling the x value and the number average molecular weight, they may be used as a temperature sensor, and the temperature during the process to be performed in the specific temperature range may be If it is out of range, this can be detected to provide smooth control of the process.

Test Example 2

Optical property test by temperature

Using a laser having a wavelength of 632.8 nm as polarized light, the scattering intensity at 90 DEG by the polarized light was measured in accordance with the temperature change while transmitting the block copolymer sample prepared in Example 4. Shown in As can be seen in FIG. 4, the low-temperature uniformity does not exhibit scattering characteristics due to polarized light due to optical isotropy. However, the scattering intensity starts to increase rapidly from 140 ° C and increases to 220 ° C, and then decreases and disappears again. This phenomenon is also due to the fact that the polymer according to the present invention forms a nanostructure at a certain temperature range and the nanostructure is destroyed again at a certain temperature or more, and this temperature range coincides with the change region of modulus shown in FIG. 2. That is, the change of optical properties is caused by the formation of nanostructures, and its application is expected as a polymer optical sensor for temperature change using these properties.

Test Example 3

Formation and extinction temperature measurement of nanostructures according to pressure changes

The block copolymer prepared according to Example 9 of the present invention was placed in a high-pressure cell, and the scattering intensity by neutrons was measured according to the temperature and each pressure while changing the temperature by 10 ° C., and the results are shown in FIG. 5. . That is, Figure 5 shows the nano-phase formation and the extinction temperature according to the pressure change for the block copolymer prepared by Example 9 of the present invention. In other words, as the pressure increases, the transition temperature is sensitively increased or decreased, indicating only a uniform phase above the critical pressure. This property is closely related to processing processes such as injection molding of polymers. That is, when forming a homogeneous phase by high pressure during injection, the flowability is increased due to the viscosity decrease, and the processability is excellent, and the pressure is reduced in the injection molder. Due to the nano-structure to form again, at this time, the modulus or viscosity increases quickly to obtain a solid product.

In addition, it has a nanostructure up to a certain pressure in a certain temperature range, but because it becomes a uniform phase when a certain pressure is exceeded, the modulus, viscosity or scattering strength changes rapidly, so using this property to detect a specific pressure at a specific temperature Can be used as

As described above, the block copolymer according to the present invention forms a nanostructure only at a specific temperature or a specific pressure, and can adjust the range of the temperature region and the pressure region according to the control of the x value or the number average molecular weight. When the block copolymer has a nanostructure, the scattering intensity of the polarized light is changed, and the modulus and viscosity of physical properties are rapidly increased. Therefore, it can be used not only as a temperature sensor due to changes in optical properties or processes requiring nanostructure at a specific temperature, but also as a pressure sensor.

Claims (10)

Polystyrene-polypentyl methacrylate block copolymer of the following formula 1 to form a nanostructure only in a specific temperature or pressure region. (One) (Wherein x and y are 0.15 ≦ x ≦ 0.85 as volume fraction and x + y = 1). The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the number average molecular weight (M) of the polystyrene-polypentyl methacrylate block copolymer satisfies the following formula (1). <Equation 1> 938572x ² -938572x + 27836≤number average molecular weight (M) ≤1036190x ² -1036190x + 306495 (Wherein x is a volume fraction of styrene) The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is 46,000 to 50,000 when x is 0.5. The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is 79,000 to 87,000 when x is 0.3. The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the number average molecular weight of the polystyrene-polypentyl methacrylate block copolymer is 159,000 to 175,000 when x is 0.15. The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the polystyrene-polypentyl methacrylate block copolymer is prepared by blending two or more block copolymers of Formula 1 having different number average molecular weights. coalescence. The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the polystyrene-polypentyl methacrylate block copolymer is prepared by blending two or more block copolymers of Formula 1 having different volume fractions of monomers. Copolymer. The polystyrene-polypentyl methacrylate block copolymer according to claim 1, wherein the polystyrene-polypentyl methacrylate block copolymer is prepared by anionic polymerization. A temperature sensor using the polystyrene-polypentyl methacrylate block copolymer according to any one of claims 1 to 8. A pressure sensor using the polystyrene-polypentyl methacrylate block copolymer according to any one of claims 1 to 8.