KR20220011392A - Nanocellulose-polyester-composite material and method for preparing the same - Google Patents

Abstract

The present invention relates to a polyester-nanocellulose composite material and a method for manufacturing the same, and more specifically relates to a polyester-nanocellulose composite material comprising polyester and nanocellulose. According to the present invention, the composite material has excellent tensile intensity and high tensile elongation.

Description

Polyester-nanocellulose composite material and manufacturing method thereof

The present invention relates to a polyester-nanocellulose composite material and a method for manufacturing the same.

Polyalkylene terephthalate-based resin is a polyester-based resin by esterification reaction and polymer polymerization reaction of terephthalic acid (TPA) or dimethyl terephthalate (DMT) and an alkylene diol compound as an alcohol component under a certain catalyst. The resulting high molecular compound is referred to.

The polyalkylene terephthalate-based resin has excellent properties such as heat resistance, transparency, strength, processability, etc. compared to polyolefin resins widely used commercially.

Such polyalkylene terephthalate-based resins include polyethylene terephthalate (PET) resins, polytrimethylene terephthalate (PTT) resins, polybutylene terephthalate (“PBT”) resins, and polycyclones. It may be classified into a polycyclohexylenedimethylene terephthalate ("PCT") resin and the like.

In particular, poly(1,4-cyclohexanedimethylene terephthalate) (Poly(1,4-cyclohexanedimethylene terephthalate), PCT) has excellent mechanical properties and chemical resistance, a high melting point, excellent heat resistance, and durability at high temperature and high humidity. It is one of the aromatic semi-crystalline polyesters characterized by this excellent and low water absorption.

In addition, since the poly(1,4-cyclohexane dimethylene terephthalate) has a higher thermal deformation temperature than poly(ethylene terephthalate, PET), it has excellent dielectric breakdown strength even at high temperatures, resulting in heat resistance It is most widely used for necessary electrical/electronic parts, automobile parts and mechanical parts.

Polyalkylene terephthalate resin has high abrasion resistance, durability and heat resistance due to high crystallinity, while high crystallization reduces tensile elongation and increases brittleness, so that it can be easily broken by an external force.

In order to solve this problem, a method of increasing the molecular weight of the resin may be considered, but as the molecular weight increases, the viscosity of the molten resin rises vertically, and accordingly, there is a problem in that the injection pressure is rapidly increased and productivity is lowered.

Republic of Korea Patent Publication No. 10-2015-0077359 (2015.07.07)

An object of the present invention for solving the above problems is to provide a polyester-nanocellulose composite material and a method for manufacturing the same, having a significant increase in tensile elongation and tensile toughness compared to a polyester resin that does not contain nanocellulose.

In addition, another object of the present invention is to provide a polyester-nanocellulose composite material having excellent compatibility without a pretreatment process such as surface hydrophobization of the nanocellulose, and having remarkably improved physical properties, and a method for manufacturing the same.

As a result of research to achieve the above object, the polyether-nanocellulose composite material according to the present invention includes polyester and nanocellulose including a repeating unit represented by the following Chemical Formula 1.

[Formula 1]

According to an aspect of the present invention, the nanocellulose may include 0.01 to 4 parts by weight based on 100 parts by weight of the polyester.

According to an aspect of the present invention, the polyester may include 50% by weight or more of the repeating unit represented by Formula 1, based on the total weight.

According to an aspect of the present invention, the nanocellulose may include cellulose having an average diameter of 2 to 200 nm and an average length of 100 nm to 10 μm.

According to an aspect of the present invention, the polyester-nanocellulose composite material may have a tensile elongation that satisfies Equation 1 below.

[Equation 1]

In the above formula 1,

The TE ₀ is the tensile elongation (%) of the polyester not containing the nanocellulose, and TE ₁ is the polyester-the tensile elongation (%) of the nanocellulose composite material.

According to an aspect of the present invention, the polyester-nanocellulose composite material is a polyester-nanocellulose composite material having tensile toughness satisfying Equation 2 below.

[Equation 2]

In the above formula 2,

The TT ₀ is the tensile toughness (MJ/m3) of the polyester not containing the nanocellulose, and the TT ₁ is the tensile toughness (MJ/m3) of the polyester-nanocellulose composite material.

According to an aspect of the present invention, the polyester-nanocellulose composite material may be prepared by a solution process.

According to an aspect of the present invention, the polyester-nanocellulose composite material may be manufactured by an in-situ polymerization process.

According to an aspect of the present invention, the polyester-nanocellulose composite material may be prepared by dropwise adding an aqueous nanocellulose dispersion or an alcohol dispersion during an in-situ polymerization process.

According to an aspect of the present invention, the polyester-nanocellulose may have a tensile strength of 51 MPa or more, a tensile elongation of 305% or more, and a tensile toughness of 134 MJ/m ^{3 or} more.

According to an aspect of the present invention, the polyester-nanocellulose may have a tensile strength of 51 MPa or more, a tensile elongation of 310% or more, and a tensile toughness of 135 MJ/m ^{3 or} more.

According to an aspect of the present invention, the polyester-nanocellulose may have a tensile strength of 70 MPa or more, a tensile elongation of 400% or more, and a tensile toughness of 270 MJ/m ^{3 or} more.

Another aspect of the present invention is a method for producing a polyester-nanocellulose composite material comprising: a) preparing a dispersion by mixing and dispersing a polyester and nanocellulose including a repeating unit represented by the following Chemical Formula 1 in a solvent; and b) drying the dispersion to prepare a composite material.

[Formula 1]

According to an aspect of the present invention, the nanocellulose may include 0.01 to 4 parts by weight based on 100 parts by weight of the polyester.

In another aspect of the present invention, the polyester-a method for producing a nanocellulose composite material is prepared by A) 1,4-cyclohexane dimethanol (CHDM), a terephthalic acid derivative, and an oligomer through an ester reaction process from a nanocellulose composition to do; and B) polymerizing the oligomer into a polyester including a repeating unit represented by the following formula (1).

[Formula 1]

According to an aspect of the present invention, step A), preparing the nanocellulose as an aqueous dispersion or an alcohol dispersion, and continuously adding it dropwise during the ester reaction to prepare an oligomer; may include.

The polyester-nanocellulose composite material according to the present invention has an advantage in that it not only has excellent tensile strength, but also has significantly higher tensile elongation and an increase in tensile toughness compared to the basic polyester that does not contain nanocellulose.

In addition, the method for producing a polyester-nanocellulose composite material according to the present invention has an advantage in that it has a synergistic effect on excellent mechanical properties through excellent composite of polyester and nanocellulose without a pretreatment process causing an increase in cost.

In addition, in another aspect of the present invention, in the method for producing a polyester-nanocellulose composite material, the nanocellulose is prepared in the form of a dispersion and continuously added during the reaction process of the monomer to prepare an oligomer. By including, It has the advantage of having a synergistic effect of excellent mechanical properties.

The present invention will be described in more detail through the following specific examples or examples. However, the following specific examples or examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention.

Also, the singular forms used in the specification and appended claims may also be intended to include the plural forms unless the context specifically dictates otherwise.

Also, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The present invention provides a polyester-nanocellulose composite material comprising a polyester and nanocellulose including a repeating unit represented by the following formula (1).

[Formula 1]

The polyester according to the present invention contains the repeating unit as described above, so that it can be mixed with nanocellulose to have excellent tensile strength, and to remarkably improve tensile elongation and tensile toughness, compared to basic polyester that does not contain nanocellulose. can In addition, it has excellent hardness, optical and UV resistance as well as mechanical properties.

According to an aspect of the present invention, the nanocellulose may include 0.01 to 4 parts by weight based on 100 parts by weight of the polyester.

Preferably, based on 100 parts by weight of the polyester, 0.05 to 2 parts by weight may be included, and more preferably 0.1 to 1 parts by weight may be included. When included in the above range, it is possible to significantly improve the tensile elongation and tensile toughness of the polyester while having excellent tensile strength by bonding with the polyester according to the present invention.

According to an aspect of the present invention, the polyester may contain 50% by weight or more of the repeating unit represented by Chemical Formula 1, preferably 50 to 90% by weight of the repeating unit represented by Chemical Formula 1, based on the total weight. %, more preferably 55 to 85% by weight.

When included in the above range, compatibility with nanocellulose can be improved, and tensile elongation and tensile toughness of the composite material can be significantly improved compared to the basic polyester.

According to an aspect of the present invention, the polyester is not particularly limited, but for a specific example, the weight average molecular weight may satisfy 10,000 to 200,000 g/mol, preferably 20,000 to 100,000 g/mol, and , more preferably 40,000 to 60,000 g/mol may be satisfied, but is not limited thereto.

According to an aspect of the present invention, the nanocellulose refers to nano/micrometer-sized rod-shaped particles or fibers in which cellulose chains are bundled together. Specifically, according to the extraction method, it may be classified into cellulose nanofibril (CNF) or cellulose nanocrystal (CNC).

According to an aspect of the present invention, the nanocellulose may include cellulose having an average diameter of 2 to 200 nm and an average length of 100 nm to 10 μm. Preferably, the nanocellulose has an average diameter of 2 to 100 nm, and may have an average length of 100 nm to 5 μm, more preferably, an average diameter of 2 to 100 nm, and an average length of 100 to 900 nm. may include In the case of including the nanocellulose as described above, the mechanical properties of the polyester according to the present invention, in particular, the synergistic effect of tensile elongation and tensile toughness is superior, which is preferable.

According to an aspect of the present invention, the polyester-nanocellulose composite material may have a tensile elongation that satisfies Equation 1 below.

[Equation 1]

In the above formula 1,

The TE ₀ is the tensile elongation (%) of the polyester not containing the nanocellulose, and TE ₁ is the polyester-the tensile elongation (%) of the nanocellulose composite material.

Preferably, Equation 1 may satisfy 120% or more. Moreover, when manufacturing the composite material, when the nanocellulose is mixed with the in-situ polymerization method during polyester polymerization, Equation 1 can satisfy 130% or more, preferably 150% or more, so it is more preferable. Even without an excessive amount of reinforcing material, the polyester-nanocellulose composite material according to the present invention can secure the excellent tensile elongation increase rate as described above, thereby increasing the flexural energy, thereby increasing the practical impact strength of the molded article, injection releasability and continuous operation The castle is very good.

According to an aspect of the present invention, the polyester-nanocellulose composite material may have excellent tensile toughness.

According to an aspect of the present invention, the polyester-nanocellulose composite material may have tensile toughness satisfying Equation 2 below.

[Equation 2]

In the above formula 2,

The TT ₀ is the tensile toughness (MJ/m3) of the polyester not containing the nanocellulose, and the TT ₁ is the tensile toughness (MJ/m3) of the polyester-nanocellulose composite material.

Preferably, Equation 2 may satisfy 130% or more. Moreover, when manufacturing the composite material, when the nanocellulose is mixed during polyester polymerization by the in-situ polymerization method, Equation 2 can satisfy 140% or more, preferably 200% or more, so it is more preferable. Even without an excessive amount of reinforcing material, the polyester-nanocellulose composite material according to the present invention can secure the excellent tensile toughness increase rate as described above, thereby preventing deformation and damage due to external impact as well as having long-term durability. .

The polyester-nanocellulose may be a polyester-nanocellulose prepared by a solution process and an in-situ polymerization process.

According to an aspect of the present invention, the polyester-nanocellulose composite material may be prepared by a solution process.

The solution process is a method for preparing a polyester-nanocellulose composite material by dissolving a polyester polymer and nanocellulose and mixing them by stirring, and it can have superior tensile strength, tensile elongation and tensile toughness than conventional polyester polymers. .

As a specific example, the tensile strength measured according to ASTM D638 may be 51 MPa or more, preferably 53 MPa or more, and more preferably 60 MPa or more. The upper limit is not particularly limited, but may preferably be 51 to 80 MPa, preferably 53 to 70 MPa, and more preferably 60 to 66 MPa. By having the tensile strength as described above, it is possible to minimize structural changes due to external impact.

In addition, the tensile elongation measured according to ASTM D638 may be 305% or more, preferably 360% or more, and more preferably 365% or more. The upper limit is not particularly limited, but the tensile elongation may be 305 to 450%, preferably 360 to 430%, and more preferably 365 to 420%.

In addition, the tensile toughness measured according to ASTM D638 ^{may be 134 MJ/m 3 or} more, preferably 175 MJ/m ^{3 or} more, and more preferably 185 MJ/m ³ or more. The upper limit is not particularly limited, but the tensile toughness may be 134 to 300 MJ/m ³ , preferably 175 to 260 MJ/m ³ , and more preferably 185 to 250 MJ/m ³ .

According to an aspect of the present invention, the polyester-nanocellulose composite material may be manufactured by an in-situ polymerization process.

By manufacturing the polyester-nanocellulose composite material through an in-situ polymerization process, it can have better mechanical strength than the polyester-nanocellulose prepared by the solution process.

As a specific example, the tensile strength measured according to ASTM D638 may be 51 MPa or more, preferably 55 MPa or more, and more preferably 65 MPa or more. The upper limit is not particularly limited, but preferably 51 to 100 MPa, preferably 55 to 80 MPa, more preferably 65 to 70 MPa. By having the tensile strength as described above, it is possible to minimize structural changes due to external impact.

In addition, the tensile elongation measured according to ASTM D638 may be 310% or more, preferably 360% or more, and more preferably 370% or more. The upper limit is not particularly limited, but the tensile elongation may be 310 to 500%, preferably 360 to 480%, and more preferably 370 to 460%.

In addition, the tensile toughness measured according to ASTM D638 ^{may be 135 MJ/m 3 or} more, preferably 190 MJ/m ^{3 or} more, and more preferably 195 MJ/m ³ or more. The upper limit is not particularly limited, but the tensile toughness may be 135 to 300 MJ/m ³ , preferably 190 to 260 MJ/m ³ , and more preferably 195 to 280 MJ/m ³ .

According to an aspect of the present invention, the polyester-nanocellulose composite material can be prepared by dropwise adding an aqueous nanocellulose dispersion or an alcohol dispersion during an in-situ polymerization process.

Polyester-nanocellulose having better mechanical properties than the in-situ polymerization process can be produced by polymerizing polyester-nanocellulose while dropping an aqueous dispersion of nanocellulose or an alcohol dispersion in the esterification reaction.

As a specific example, the tensile strength measured according to ASTM D638 may be 70 MPa or more, preferably 71 MPa or more, and more preferably 72 MPa or more. The upper limit is not particularly limited, but may preferably be 70 to 100 MPa, preferably 71 to 80 MPa, and more preferably 72 to 75 MPa. By having the tensile strength as described above, it is possible to minimize structural changes due to external impact.

In addition, the tensile elongation measured according to ASTM D638 may be 400% or more, preferably 430% or more, and more preferably 460% or more. The upper limit is not particularly limited, but the tensile elongation may be 400 to 500%, preferably 430 to 480%, and more preferably 460 to 490%.

In addition, the tensile toughness measured according to ASTM D638 ^{may be 270 MJ/m 3 or} more, preferably 275 MJ/m ^{3 or} more, and more preferably 280 MJ/m ³ or more. The upper limit is not particularly limited, but the tensile toughness may be 270 to 400 MJ/m ³ , preferably 275 to 350 MJ/m ³ , and more preferably 280 to 300 MJ/m ³ .

The solution process and the in-situ polymerization method will be described in detail.

First, the solution process (Solution method) of the method for producing a polyester-nanocellulose composite material according to the present invention is a) a dispersion solution by mixing and dispersing a polyester and nanocellulose containing a repeating unit represented by the following formula (1) in a solvent manufacturing a; and b) drying the dispersion to prepare a composite material.

[Formula 1]

According to an aspect of the present invention, the solvent in step a) is not particularly limited as long as it can dissolve the polyester and nanocellulose can be dispersed, but specific examples include trifluoroacetic acid, methylene chloride, chloroform , tetrahydrofuran, methacresol, cyclohexane, dioxane, dimethylformaldehyde, pyridine, dimethylformamide, dimethylacetamide, formic acid, phenol, and xylene may be any one or a mixed solvent of two or more, preferably Preferably, it may be a mixed solvent of trifluoroacetic acid and chloroform.

The mixing ratio of trifluoroacetic acid and chloroform may be 1:2, but if the polyester and nanocellulose are completely dissolved, it is not limited thereto.

As described above, if drying is easy when mixing and dispersing in a solvent in step a), the concentration and mixing method of the dispersion are not particularly limited. For a specific example, the dispersion may contain 5 to 20 parts by weight of the total weight of polyester and nanocellulose, preferably 5 to 15 parts by weight, more preferably 10 to 15 parts by weight, based on 100 parts by weight of the solvent. It may be manufactured, but is not limited thereto.

According to one aspect of the present invention, in step b), the dispersion is not particularly limited as long as the solvent is volatilized, but is preferably dried at room temperature to 250° C. under atmospheric pressure or vacuum for 1 to 60 hours. However, the present invention is not limited thereto.

According to an aspect of the present invention, the polyester-nanocellulose composite material can not only be easily manufactured in the solution process as described above, but also has excellent tensile strength by combining polyester and nanocellulose, while nanocellulose It is possible to significantly improve tensile elongation and tensile toughness compared to polyester that does not contain

According to an aspect of the present invention, the nanocellulose in step a) may include 0.01 to 4 parts by weight based on 100 parts by weight of the polyester. Preferably, based on 100 parts by weight of the polyester, it may contain 0.05 to 2 parts by weight, more preferably 0.1 to 1 parts by weight. When included in the above range, while having excellent tensile strength, the increase rate of tensile elongation and tensile toughness can be realized at significantly high values.

The method for producing a polyester-nanocellulose composite material according to the present invention can significantly improve the mechanical properties of the composite material compared to the single mechanical properties of the polyester resin. This improvement effect can be implemented.

As another method of the polyester-nanocellulose composite material manufacturing method according to the present invention, the in-situ method is according to another aspect of the present invention, A) 1,4-cyclohexane dimethanol (CHDM), a terephthalic acid derivative and It may include the steps of preparing an oligomer through an ester reaction proceeding from the nanocellulose composition, B) polymerizing the oligomer into a polyester including a repeating unit represented by the following formula (1).

[Formula 1]

The in-situ ester reaction is a bulk polymerization reaction, and the nanocellulose may be uniformly dispersed and difficult to polymerize.

Accordingly, according to one aspect of the present invention, in step A), nanocellulose can be prepared as an aqueous dispersion or alcohol dispersion and continuously added dropwise during the esterification reaction, and the nanocellulose can be very uniformly dispersed during the esterification reaction.

By adding the dispersion solution dropwise, as the nanocellulose is more uniformly dispersed and participates in the ester reaction, it is possible to have a remarkable effect of increasing mechanical strength such as superior tensile elongation and tensile strength.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following examples and comparative examples are merely examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

[Method of measuring physical properties]

(1) Tensile strength, tensile elongation and tensile toughness

Examples and comparative examples were placed in the cylinder of the Haake™ Minijet (Thermo Scientific) injection machine, and the cylinder temperature was 350°C, the exposure time was 5 minutes, the injection pressure was 500 bar, and the mold temperature was 150°C, and the dog-bone-shaped specimen (length: 25.5 mm, width: 3.11 mm, thickness: 3.1 mm) was manufactured, and a tensile test was performed according to ASTM D 638 using a universal testing machine (UTM 5982, INSTRON).

The increase in tensile elongation (%) was calculated using Equation 1 below compared to the tensile elongation of the polyester corresponding to the synthesis example.

[Formula 1]

Tensile elongation increase rate = (tensile elongation of composite material including nanocellulose / tensile elongation of resin without nanocellulose) × 100

Tensile toughness increase rate (%) was calculated by calculating the increase rate compared to the polyester tensile toughness corresponding to the synthesis example through Equation 2 below.

[Formula 2]

Tensile toughness increase rate = (tensile elongation of composite material including nanocellulose / tensile toughness of resin without nanocellulose) × 100

(2) weight average molecular weight

The weight average molecular weight is a weight average molecular weight value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

For the gel permeation chromatography (GPC) measurement, an ACQUITY APC device from Waters was used, and an ACQUITY APC XT from Waters was used for the column to be bound therein. In addition, as the GPC solvent, hexafluoroisopropanol (Hexafluoro-2-propanol) was used, and the temperature inside the column was 40° C. and the flow rate was 0.6 ml/min.

[Example 1]

Terephthalic acid (TPA) (59.8 g, 0.360 mol), 1,4-cyclohexanedimethanol (CHDM)) (62.3 g, 0.432 mol), nanocellulose 50 mg (average diameter 20 nm, average length 300 nm, 0.05 wt% based on theoretical obtained weight), germanium oxide (Ge ₂ O) (150 ppm, relative to the total weight of the monomers) and dibutyl tinoxide (DBTO)) (150 ppm , relative to the total weight of the monomers) was added to the reactor.

The ratio of the alcohol monomer to the monomer of the carboxylic acid derivative was fixed at 1:1.2. The ester reaction was performed to prepare an oligomer by stirring at 280°C for 4 hours.

The completion of the reaction was confirmed by calculating the amount of water generated. As the next step, the temperature was raised to 290 °C, and the stirring speed was gradually reduced while the vacuum degree was gradually lowered to 0.4 mbar. The condensation reaction was terminated when the torque reached 2.5 Nm. The vacuum was released under normal pressure, and it was precipitated in a water-coagulation bath to obtain 98 g of a weight average molecular weight of 55,000 g/mol polyester-nanocellulose composite material (yield: 98%).

[Example 2]

In Example 1, the same preparation was followed except that 100 mg (0.1 wt% of the theoretical obtained weight) of the nanocellulose was added when mixing the monomers, and the polymerization resulted in a weight average molecular weight of 50,000 g/mol polyester-nano 98 g of a cellulose composite material (yield: 98%) was obtained.

[Example 3]

In Example 1, the same preparation was followed except that 1 g (1 wt% of the theoretical obtained weight) of the nanocellulose was added when mixing the monomers, and the polymerization resulted in a weight average molecular weight of 49,000 g/mol polyester-nano 98 g of a cellulose composite material (yield: 98%) was obtained.

[Example 4]

In Example 1, the same preparation was followed except that 2 g (2 wt% of the theoretical obtained weight) of the nanocellulose was added when mixing the monomers, and the polymerization resulted in a weight average molecular weight of 48,000 g/mol polyester-nano 98 g of a cellulose composite material (yield: 98%) was obtained.

[Example 5]

In Example 2, an aqueous solution (0.5 wt%, 20 g) in which 100 mg of nanocellulose (0.1 wt% relative to the theoretical obtained weight) is dispersed was continuously dropped during the esterification reaction of CHDM and TPA except that The same preparation method as in Example 2 was followed, and 98 g (yield: 98%) of a weight average molecular weight of 55,000 g/mol polyester-nanocellulose composite material was obtained through the polymerization.

[Example 6]

In Example 2, a methanol solution (0.5 wt%, 20 g) in which 100 mg of nanocellulose (0.1 wt% relative to the theoretical obtained weight) is dispersed was continuously dropped during the esterification reaction of CHDM and TPA except that followed the same preparation method as in Example 2, and 98 g (yield: 98%) of a weight average molecular weight of 53,000 g/mol polyester-nanocellulose composite material was obtained through the polymerization.

[Example 7]

In Example 1, the same preparation was followed except that 5 mg (0.005 wt% of the theoretical obtained weight) of the nanocellulose was added when mixing the monomers, and the polymerization resulted in a weight average molecular weight of 53,000 g/mol polyester-nano 98 g of a cellulose composite material (yield: 98%) was obtained.

[Example 8]

In Example 1, the same preparation was followed except that 5 g (5 wt% of the theoretical obtained weight) of the nanocellulose was added when mixing the monomers, and the polymerization resulted in a weight average molecular weight of 46,000 g/mol polyester-nano 98 g of a cellulose composite material (yield: 98%) was obtained.

[Example 9]

Terephthalic acid (TPA) (59.8 g, 0.360 mol), ,4-cyclohexanedimethanol (CHDM) (62.3 g, 0.432 mol), germanium oxide (Ge ₂ O) (150 ppm, relative to the total weight of the monomers) and dibutyl tinoxide (DBTO) (150 ppm, relative to the total weight of the monomers) were added to the reactor.

The ratio of the alcohol monomer to the monomer of the carboxylic acid derivative was fixed at 1:1.2. The ester reaction was performed to prepare an oligomer by stirring at 280°C for 4 hours.

The completion of the reaction was confirmed by calculating the amount of water generated. As the next step, the stirring speed was gradually reduced while raising the temperature to 290 degrees and lowering the vacuum degree to 0.4 mbar gradually. The condensation reaction was terminated when the torque reached 2.5 Nm. The vacuum was released under normal pressure and precipitated in a water-coagulation bath to obtain 98 g of a weight average molecular weight polyester composite material (yield: 98%).

Trifluoroacetic acid: chloroform = 1:2 with 10 g of the polyester and 0.5 mg of nanocellulose (average diameter 20 nm, average length 300 nm); After dissolving in 100 g of a mixed solvent, the mixture was stirred at room temperature for 2 hours. A polyester-nanocellulose composite material was prepared by ultrasonication using a bath sonicator for 10 minutes and volatilizing and drying the solvent for 24 hours while gradually increasing the temperature at 80°C. (Nanocellulose content: 0.005 wt%)

[Example 10]

The same procedure was performed except that 5 mg of nanocellulose was used in Example 9. (Nanocellulose content: 0.05 wt%)

[Example 11]

The same procedure was performed except that 10 mg of nanocellulose was used in Example 9. (Nanocellulose content: 0.1 wt%)

[Example 12]

The same procedure was performed except that 100 mg of nanocellulose was used in Example 9. (Nanocellulose content: 1 wt%)

[Example 13]

The same procedure was performed except that 200 mg of nanocellulose was used in Example 9. (Nanocellulose content: 2 wt%)

[Example 14]

The same procedure was performed except that 500 mg of nanocellulose was used in Example 9. (Nanocellulose content: 5 wt%)

[Comparative Example 1]

The same manufacturing method was followed except that the nanocellulose was not added when mixing the monomers in Example 1, and 98 g of a weight average molecular weight of 51,000 g/mol polyester-nanocellulose composite material (yield: 98%) was obtained by the polymerization. .

Nanocellulose content (wt%) Tensile strength (MPa) Tensile Elongation (%) Tensile toughness (MJ/m ³ ) The degree of improvement in toughness of composite materials compared to polymers (multiple) Example 1 0.05 55 390 215 1.65 Example 2 0.1 70 450 270 2.08 Example 3 One 66 370 198 1.52 Example 4 2 65 361 192 1.48 Example 5 0.1 74 480 295 2.27 Example 6 0.1 72 470 284 2.18 Example 7 0.005 51 310 138 1.06 Example 8 5 40 120 44 0.34 Example 9 0.005 51 305 134 1.03 Example 10 0.05 53 370 195 1.50 Example 11 0.1 65 410 245 1.88 Example 12 One 60 368 185 1.42 Example 13 2 58 362 178 1.33 Example 14 5 35 105 32 0.25 Comparative Example 1 0 50 300 130 -

Comparative Example 1 is a polyester polymer, and compared with Examples 1 to 7 or Examples 9 to 13, it was confirmed that the tensile strength, tensile elongation and tensile toughness values were overall improved. In particular, when the nanocellulose content was 0.05 to 2, the synergistic effect of pulling elongation and tensile toughness was remarkably high.

In addition, it was confirmed that when the polyester-nanocellulose composite material was prepared by an in-situ polymerization process rather than a solution process, it had better mechanical properties.

Moreover, in the in-situ polymerization process, it was confirmed that the nanocellulose aqueous solution or alcohol dispersion was added dropwise during the oligomerization reaction to have better mechanical properties.

As described above, the present invention has been described with reference to specific matters and limited examples and drawings, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is not limited to the above embodiments. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (16)

A polyester-nanocellulose composite material comprising a polyester and nanocellulose comprising a repeating unit represented by the following formula (1).
[Formula 1]

The method of claim 1,
The nanocellulose is polyester-nanocellulose composite material comprising 0.01 to 4 parts by weight based on 100 parts by weight of the polyester. The method of claim 1,
The polyester is a polyester-nanocellulose composite material comprising 50% by weight or more of the repeating unit represented by Formula 1, based on the total weight. The method of claim 1,
The nano-cellulose is a polyester-nanocellulose composite material comprising cellulose having an average diameter of 2 to 200 nm, and an average length of 100 nm to 10 μm. The method of claim 1,
The polyester-nanocellulose composite material is a polyester-nanocellulose composite material having a tensile elongation that satisfies Equation 1 below.
[Equation 1]

In the above formula 1,
The TE ₀ is the tensile elongation (%) of the polyester not containing the nanocellulose, and TE ₁ is the polyester-the tensile elongation (%) of the nanocellulose composite material. The method of claim 1,
The polyester-nanocellulose composite material is a polyester-nanocellulose composite material having tensile toughness satisfying Equation 2 below.
[Equation 2]

In Equation 2,
The TT ₀ is the tensile toughness (MJ/m3) of the polyester not containing the nanocellulose, and the TT ₁ is the tensile toughness (MJ/m3) of the polyester-nanocellulose composite material. The method of claim 1,
The polyester-nanocellulose composite material is a polyester-nanocellulose composite material manufactured by a solution process. The method of claim 1,
The polyester-nanocellulose composite material is a polyester-nanocellulose composite material manufactured by an in-situ polymerization process. 9. The method of claim 8,
The polyester-nanocellulose composite material is a polyester-nanocellulose composite material prepared by dropwise adding an aqueous nanocellulose dispersion or an alcohol dispersion during the in-situ polymerization process. 8. The method of claim 7
The polyester-nanocellulose is a polyester-nanocellulose composite material that has a tensile strength of 51 MPa or more, a tensile elongation of 305% or more, and a tensile toughness of 134 MJ/m ^{3 or more.} 9. The method of claim 8
The polyester-nanocellulose is a polyester-nanocellulose composite material that has a tensile strength of 51 MPa or more, a tensile elongation of 310% or more, and a tensile toughness of 135 MJ/m ^{3 or more.} 10. The method of claim 9
The polyester-nanocellulose is a polyester-nanocellulose composite material having a tensile strength of 70 MPa or more, a tensile elongation of 400% or more, and a tensile toughness of 270 MJ/m ^{3 or more.} a) preparing a dispersion by mixing and dispersing a polyester and nanocellulose containing a repeating unit represented by the following Chemical Formula 1 in a solvent; and
b) drying the dispersion to prepare a composite material;
A method for producing a polyester-nanocellulose composite material comprising a.
[Formula 1]

14. The method of claim 13,
The nanocellulose is polyester containing 0.01 to 4 parts by weight with respect to 100 parts by weight of the polyester-a method of manufacturing a nanocellulose composite material. A) 1,4-cyclohexane dimethanol (CHDM), a terephthalic acid derivative, and preparing an oligomer through an ester reaction proceeding from a nanocellulose composition; and
B) polymerizing the oligomer into a polyester including a repeating unit represented by the following formula (1);
A method for producing a polyester-nanocellulose composite material comprising a.
[Formula 1]

16. The method of claim 15,
In the step A), the nanocellulose is prepared as an aqueous dispersion or an alcohol dispersion and continuously added dropwise during the ester reaction to prepare an oligomer; polyester- manufacturing method of a nanocellulose composite material comprising a.