WO2022255615A1 - Biodegradable furan-based composite having improved mechanical properties, and method for producing same - Google Patents

Abstract

The present disclosure relates to: a furan-based biodegradable composite produced by polymerizing a furan-based dicarboxylic acid or derivative thereof, an aliphatic dicarboxylic acid or derivative thereof, an aliphatic diol, and a natural polymer nanofiber; and a method for producing same. The biodegradable composite according to one embodiment may have significantly improved mechanical properties due to the natural polymer nanofibers being uniformly dispersed and cross-linked.

Description

Biodegradable furan-based composite having improved mechanical properties and method for preparing the same

The present disclosure relates to a biodegradable furan-based composite having improved mechanical properties and a method for preparing the same.

Currently commercialized resins, such as polyethylene and polypropylene, generally utilize petroleum-based monomers, and have poor degradability in a natural state, adversely affecting the environment when discarded after use.

However, petroleum-based resins have excellent mechanical properties such as durability, and the proportion of products using them is gradually increasing. This is emerging as a problem to be solved in today's world, when environmental issues are particularly important, and research and development on eco-friendly materials that can replace petroleum-based resins is required worldwide.

As one of the methods for this, there is a method of synthesizing a biodegradable resin using biomass or petroleum-based monomers. As an example of this, biodegradable polyester, when the ester functional group is exposed to external water and air, hydrolysis occurs, enabling biodegradation. Specifically, such polyesters include poly butylene adipate terephthalate (PBAT), poly butylene succinate (PBS), poly lactic acid (PLA), and the like.

However, these biodegradable polyesters show inferior aspects to petroleum-based resins in mechanical properties, commercial value or marketability, and price competitiveness. In particular, there is a problem that mechanical properties, for example, tensile strength or elongation are very inferior to petroleum-based resins, and research and development to solve this problem are urgent.

One embodiment is to provide a biodegradable furan-based composite having improved mechanical properties and a method for preparing the same.

In order to achieve the above purpose,

One embodiment provides a biodegradable composite prepared by polymerizing furan-based dicarboxylic acids or derivatives thereof, aliphatic dicarboxylic acids or derivatives thereof, aliphatic diols, and natural polymer nanofibers.

In this case, the natural polymer nanofibers may be at least one selected from nanochitin fibers and nanocellulose fibers.

The content of the natural polymer nanofibers may be 0.005 to 2% by weight based on 100% by weight of the entire biodegradable composite.

The natural polymer nanofibers may have an average diameter of 1 to 200 nm and a length of 100 nm to 100 μm.

The biodegradable composite may be one that satisfies the following formula 1,

[Equation 1]

At this time, TS ₁ is the tensile strength (MPa) of the biodegradable composite, and TS ₀ is the tensile strength (MPa) when polymerized without including the natural polymer nanofibers.

Another embodiment includes preparing a mixture containing a furan-based dicarboxylic acid or derivative thereof, an aliphatic dicarboxylic acid or derivative thereof, and an aliphatic diol;

dispersing natural polymer nanofibers in the mixture; and

It provides a method for producing a biodegradable composite comprising; polymerizing the mixture in which the natural polymer nanofibers are dispersed.

In another embodiment, dispersing natural polymer nanofibers in an aliphatic diol; and

It provides a method for producing a biodegradable composite comprising mixing and polymerizing an aliphatic diol in which the natural polymer nanofibers are dispersed, a furan-based dicarboxylic acid or a derivative thereof, and an aliphatic dicarboxylic acid or a derivative thereof.

In the step of dispersing the natural polymer nanofibers in the aliphatic diol, distilled water in which the natural polymer nanofibers are dispersed may be introduced into and dispersed in the aliphatic diol.

The mechanical properties of the biodegradable composite according to one embodiment are remarkably improved by including a furan-based dicarboxylic acid or a derivative thereof. The manufacturing method of the biodegradable composite according to one embodiment is economical and effective because it does not require a pre-treatment process for hydrophobicization of natural polymer nanofibers, a melt kneading process, a solution mixing process, and the like.

Hereinafter, the present invention will be described in detail.

Meanwhile, the embodiments of the present invention may be modified in various forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Furthermore, "include" a certain component throughout the specification means that other components may be further included without excluding other components unless otherwise stated. In addition, singular forms also include plural forms unless specifically stated otherwise in the text.

One embodiment provides a biodegradable composite prepared by polymerizing furan-based dicarboxylic acids or derivatives thereof, aliphatic dicarboxylic acids or derivatives thereof, aliphatic diols, and natural polymer nanofibers.

In this case, the furan-based dicarboxylic acid or derivative thereof may be used without particular limitation as long as it is a dicarboxylic acid compound or derivative thereof containing a furan (C ₄ H ₄ O) ring, and two or more furan-based dicarboxylic acids or derivatives thereof may be a mixture. For example, the furan-based dicarboxylic acid or derivative thereof is one in which a substituent, such as an alkyl, cycloalkyl, or heterocycloalkyl, independently of two carboxyl groups or a carboxyl group, is independently substituted on a furan ring. It may be in a substituted form. In addition, for example, a substituent usually substituted on the furan ring, for example, -OH, -CN, -NH ₂ , -NO ₂ , halogen, alkyl, alkoxy, cycloalkyl or heterocycloalkyl may be further connected. may be Specifically, for example, dimethyl furan-2,5-dicarboxylate, dimethyl furan-2,4-dicarboxylate, dimethyl furan-2,3-dicarboxylate, dimethyl furan-3,4-dicarboxylate, dicarboxylate Ethyl furan-2,5-dicarboxylate, dipropyl furan-2,5-dicarboxylate, 5-(methoxycarbonyl)furan-2-carboxylic acid, dipropyl furan-2,5-dicarboxylate, 5 It may be -(ethoxycarbonyl)furan-2-carboxylic acid or 5-(methoxycarbonyl)furan-3-carboxylic acid, but is not necessarily limited thereto.

The composite polymerized from the furan-based compound according to one embodiment is effective because the reinforcing effect of the nanofibers is further improved due to the decrease in crystallinity compared to the case of using the terephthal-based compound by using the furan-based compound. In addition, since the furan-based compound can be derived from biomass, it is possible to manufacture 100% bio-based biodegradable plastic using the biodegradable composite according to the present invention.

Among the aliphatic dicarboxylic acids or derivatives thereof, the aliphatic dicarboxylic acid is not particularly limited, but is selected from, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, serveric acid, azelaic acid, and sebacic acid. can be one or more of the

The aliphatic diol is not particularly limited, but examples thereof include ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1 ,6-hexanediol, 2,4-dimethyl-2-ethyl-1,3-hexanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol , 2-ethyl-2-isobutyl-1,3-propanediol and 2,2,4-trimethyl-1,6-hexanediol.

The natural polymer nanofibers may mean natural polymer materials that exist in nature, which are not particularly limited, but may mean, for example, those made from chitin or cellulose, and are already known in the art. It may be any one or more selected from nanochitin fibers or nanocellulose fibers prepared by converting chitin or cellulose into nanofibers by a known physical or chemical method.

The content of the natural polymer nanofibers may be 0.005 to 2% by weight based on 100% by weight of the total biodegradable composite, but is not necessarily limited to the above weight range, for example, 0.001 to 1.5% by weight, 0.005 to 1.5% by weight. 0.001 to 1%, 0.005 to 1%, 0.001 to 0.5%, 0.005 to 0.5%, 0.01 to 1.5%, 0.01 to 1%, or 0.01 to 0.05%.

The natural polymer nanofibers may have an average diameter of 1 to 200 nm, but are not necessarily limited to the diameter range, and may be, for example, 1 to 100 nm or 1 to 50 nm. In addition, the natural polymer nanofibers may have a length of 100 nm to 100 μm, but are not necessarily limited to the length range, and may be, for example, 100 nm to 10 μm or 500 nm to 10 μm. Natural polymer nanofibers having the above diameter and length ranges are effective because of their excellent dispersibility, and the biodegradable composite can have remarkably improved mechanical properties by including the natural polymer nanofibers in a uniform distribution.

A biodegradable composite according to an embodiment is not particularly limited, but may satisfy Equation 1 below.

[Equation 1]

In Equation 1, TS ₁ is the tensile strength (MPa) of the biodegradable composite, and TS ₀ is the tensile strength (MPa) when polymerized without the natural polymer nanofibers.

In addition, the biodegradable composite according to one embodiment has a tensile strength of 60 MPa or more, 65 MPa or more, 70 MPa or more, 75 MPa or more, or 80 MPa or more when measured at 25 ° C. with a load cell of 1 kN and a crosshead speed of 100 mm / min. can

The biodegradable composite according to an embodiment has significantly improved mechanical properties by forming cross-linking points in which the components are polymerized from the monomer phase and the natural polymer nanofibers are uniformly distributed in the biodegradable composite. Therefore, the biodegradable composite can be effectively applied to new functional materials, water-dispersible nano fillers, and the like.

In one embodiment, preparing a mixture comprising a furan-based dicarboxylic acid or derivative thereof, an aliphatic dicarboxylic acid or derivative thereof, and an aliphatic diol;

dispersing natural polymer nanofibers in the mixture; and

It provides a method for producing a biodegradable composite comprising; polymerizing the mixture in which the natural polymer nanofibers are dispersed.

The manufacturing method according to an embodiment is not simply physically mixing polyester and natural polymer nanofibers, but polymerizing the above-described components from the monomer phase. Accordingly, a biodegradable composite having excellent mechanical properties can be prepared by uniformly dispersing and cross-linking the natural polymer nanofibers.

In one embodiment, dispersing natural polymer nanofibers in aliphatic diol; and

It provides a method for producing a biodegradable composite comprising mixing and polymerizing an aliphatic diol in which the natural polymer nanofibers are dispersed, a furan-based dicarboxylic acid or a derivative thereof, and an aliphatic dicarboxylic acid or a derivative thereof.

In the case of preparing the biodegradable composite by the above manufacturing method, the components can be more reliably polymerized from the monomer phase, and the natural polymer nanofibers can form crosslinking points more uniformly distributed in the biodegradable composite. Thus, there is an effect that can significantly improve the mechanical properties of the biodegradable composite.

In this case, in the step of dispersing the natural polymer nanofibers in the aliphatic diol, distilled water in which the natural polymer nanofibers are dispersed may be introduced into and dispersed in the aliphatic diol. In this case, the above effects are further enhanced, and a biodegradable composite having significantly improved mechanical properties can be prepared. In the preparation method, the aliphatic dicarboxylic acids or derivatives thereof, aromatic dicarboxylic acids or derivatives thereof, aliphatic diols, and natural polymer nanofibers may be applied as described above.

Hereinafter, examples and experimental examples of the present invention will be specifically illustrated and described. However, Examples and Experimental Examples to be described later are merely illustrative of a part of the present invention, and the present invention is not limited thereto.

<Evaluation method>

Tensile test: To measure tensile strength and elongation, polymer and composite samples were hot-pressed at 150 degrees Celsius and 100 bar pressure for 5 minutes to have a thickness of 0.5 mm, and then tested according to ASTM D412 standard using Intstron 5943 equipment. The cut specimens were measured. The measurement was performed at 25° C. with a load cell of 1 kN and a crosshead speed of 100 mm/min, and the average value was obtained by measuring 5 times.

< Example 1 to 4>

0.05 wt% of nanochitin fibers (0.05 g, average diameter 20 nm, average length 1 μm) was added to 1,4-butanediol (0.76 mol, 68.30 g), compared to the theoretical yield of the final product (100 g). and sufficiently dispersed using an ultrasonic generator.

Thereafter, 1,4-butanediol in which nanochitin fibers were dispersed, adipic acid (0.24 mol, 34.61 g) and dimethyl furan-2,5-dicarboxylate (0.24 mol, 44.20 g) were added to a 4-necked reactor (500 mL). Then, an overhead stirrer, a nitrogen inlet and a condenser were installed, and the mixture was stirred at 10 rpm for 1 hour and purged with nitrogen.

Then, after completely melting the mixture by heating to 140 °C for esterification, Ti(OBu) ₄ as a catalyst was added at 500 ppm based on the total weight of adipic acid and dimethyl furan-2,5-dicarboxylate in the mixture. . Then, while stirring at 150 rpm, the reactor was heated to 180 °C at a rate of 10 °C/min, and maintained for 2 hours. Thereafter, the temperature was raised to 210 ° C. and maintained for 2 more hours to remove by-products.

Thereafter, the product was transferred to a reactor (250 mL) equipped with a vacuum outlet and an overhead stirrer, and then heated to 170 °C while the inside of the reactor was completely purged with nitrogen. After the product was completely melted, the mixture was heated to 240 °C at a rate of 10 °C/min, the stirring speed was maintained at 50 rpm, and the temperature was adjusted to 100 mTorr or less through gradual pressure reduction. When the viscosity of the internal reactant increased by measuring the torque through an overhead stirrer, the stirring speed was reduced to 30 rpm and maintained for 60 minutes.

Then, the final product was quenched with water and dried in a vacuum oven at room temperature for 48 hours to prepare a biodegradable composite.

Only the input amount of nanochitin fibers was changed to 0.1 wt% (Example 2), 0.005 wt% (Example 3), and 2.0 wt% (Example 4), respectively, and the above process was repeated, Examples 2 to 4 A biodegradable composite according to was further prepared.

Tensile strength and elongation of the prepared biodegradable composites were measured according to the above evaluation method, and are listed in Table 1 below.

< Example 5 to 8>

Instead of the nanochitin fibers in Example 1, 0.05 wt% (Example 5), 0.1 wt% (Example 6), 0.005 wt% (Example 7), and 2.0 wt% (Example 8) of nanocellulose fibers, respectively. ), and the biodegradable composite according to Examples 5 to 8 was prepared in the same manner as in Example 1, except that it was added as.

Tensile strength and elongation of the prepared biodegradable composites were measured according to the above evaluation method, and are listed in Table 1 below.

< Example 9>

Example 9 was carried out in the same manner as in Example 1, except that in Example 1, 0.05 wt% of nanochitin fibers were pre-dispersed in distilled water (5 mL) and then added to 1,4-butanediol to disperse them. A biodegradable composite was prepared according to.

Tensile strength and elongation of the prepared biodegradable composites were measured according to the above evaluation method, and are listed in Table 1 below.

< comparative example 1>

PBAF (poly butylene adipate furanoate) was prepared in the same manner as in Example 1, except that nanochitin fibers were not used in Example 1.

Tensile strength and elongation were measured for the prepared PBAF, and are shown in Table 1 below.

< comparative example 2>

Except for adding dimethyl terephthalate (0.24 mol, 45.99 g) instead of dimethyl furan-2,5-dicarboxylate (0.24 mol, 44.20 g) in Comparative Example 1, the same procedure as in Comparative Example 1 was performed. To prepare poly butylene adipate terephthalate (PBAT).

Tensile strength and elongation were measured for the prepared PBAT, and are listed in Table 1 below.

< comparative example 3 to 6>

In Examples 1 to 4, except that dimethyl terephthalate (0.24 mol, 45.99 g) was added instead of dimethyl furan-2,5-dicarboxylate (0.24 mol, 44.20 g), each Example 1 In the same manner as in 4 to 4, a biodegradable composite was prepared (Comparative Example 3: Nanochitin content (0.05 wt%), Comparative Example 4: Nanochitin content (0.1 wt%), Comparative Example 5: Nanochitin content (0.005 wt%) %), Comparative Example 6: Nanochitin content (2.0 wt%)).

Tensile strength and elongation of the prepared biodegradable composites were measured according to the above evaluation method, and are listed in Table 1 below.

	polymer type	Nanofiber input (wt%)	The tensile strength (MPa)	elongation (%)
Example 1	PBAF	0.05	72	1070
Example 2	PBAF	0.1	80	1090
Example 3	PBAF	0.005	67	1040
Example 4	PBAF	2.0	52	900
Example 5	PBAF	0.05	70	1060
Example 6	PBAF	0.1	79	1070
Example 7	PBAF	0.005	67	1020
Example 8	PBAF	2.0	51	890
Example 9	PBAF	0.05	75	1080
Comparative Example 1	PBAF	-	55	1010
Comparative Example 2	PBAT	-	60	920
Comparative Example 3	PBAT	0.05	65	930
Comparative Example 4	PBAT	0.1	68	930
Comparative Example 5	PBAT	0.005	62	920
Comparative Example 6	PBAT	2.0	58	870

As a result, as can be seen in Table 1, the biodegradable composites according to Examples of the present invention showed excellent mechanical properties with significantly improved tensile strength and elongation. Specifically, the tensile strength and elongation of the PBAFs of Examples 1 to 4 containing furan-based compounds were significantly improved compared to the PBAT of Comparative Examples 3 to 6, so that the tensile strength of PBAF during in situ polymerization was improved more than that of PBAT. It was confirmed that the effect was more excellent.

In particular, Example 1 having a nanofiber content of 0.05 wt% had a tensile strength of 72 MPa, and Example 2 having a nanofiber content of 0.1 wt% had a tensile strength of 80 MPa, which was confirmed to have a very good tensile strength. This is because the reinforcing effect of the nanofibers is further increased due to the decrease in crystallinity of the composite by using the furan-based dicarboxylic acid derivative. On the other hand, in the case of Comparative Example 1 not containing natural polymer nanofibers, very poor mechanical properties were exhibited.

In addition, in the case of Example 9 in which the nanochitin fibers were previously dispersed in distilled water and then added to and dispersed in 1,4-butanediol, the tensile strength and elongation were higher compared to Example 1 in which 0.05 wt% of the nanofibers were added. improvement could be observed.

Through this, it can be seen that the mechanical properties of the biodegradable composite containing the furan-based dicarboxylic acid or its derivative are significantly improved compared to the composite containing the terephthalic dicarboxylic acid derivative due to the improved nanofiber reinforcing effect. In addition, since furan-based compounds can be converted from biomass, bio-based biodegradable plastics can be manufactured using the biodegradable composite according to the present invention, which is effective.

In the above, the present invention has been described in detail through preferred embodiments and experimental examples, but the scope of the present invention is not limited to specific examples, and should be interpreted by the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

Claims (8)

1. A biodegradable composite prepared by polymerizing furan-based dicarboxylic acids or derivatives thereof, aliphatic dicarboxylic acids or derivatives thereof, aliphatic diols, and natural polymer nanofibers.
2. According to claim 1,

   The natural polymer nanofibers are at least one selected from nanochitin fibers and nanocellulose fibers, the biodegradable composite.
3. According to claim 1,

   The content of the natural polymer nanofibers is 0.005 to 2% by weight based on 100% by weight of the total biodegradable composite, biodegradable composite.
4. According to claim 1,

   The natural polymer nanofibers have an average diameter of 1 to 200 nm and a length of 100 nm to 100 μm, a biodegradable composite.
5. According to claim 1,

   The biodegradable composite, which satisfies the following formula 1, is a biodegradable composite:

   [Equation 1]

   

   In Equation 1, TS ₁ is the tensile strength (MPa) of the biodegradable composite, and TS ₀ is the tensile strength (MPa) when polymerized without the natural polymer nanofibers.
6. preparing a mixture containing a furanic dicarboxylic acid or derivative thereof, an aliphatic dicarboxylic acid or derivative thereof, and an aliphatic diol;

   dispersing natural polymer nanofibers in the mixture; and

   Method for producing a biodegradable composite comprising; polymerizing the mixture in which the natural polymer nanofibers are dispersed.
7. dispersing natural polymer nanofibers in aliphatic diol; and

   A method for producing a biodegradable composite comprising mixing and polymerizing an aliphatic diol in which the natural polymer nanofibers are dispersed, a furan-based dicarboxylic acid or a derivative thereof, and an aliphatic dicarboxylic acid or a derivative thereof.
8. According to claim 7,

   In the step of dispersing the natural polymer nanofibers in the aliphatic diol, distilled water in which the natural polymer nanofibers are dispersed is added to the aliphatic diol to disperse them.