KR102131286B1 - Bio-degradable composite with improved mechanical properties and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a biodegradable composite in which natural polymer nanofibers are uniformly dispersed and cross-linked to have significantly improved mechanical properties, and a method for manufacturing the same.

Description

Biodegradable composite with improved mechanical properties and method for manufacturing the same{BIO-DEGRADABLE COMPOSITE WITH IMPROVED MECHANICAL PROPERTIES AND MANUFACTURING METHOD THEREOF}

The present invention relates to a biodegradable composite having improved mechanical properties and a method for manufacturing the same.

Currently commercially available resins, such as polyethylene and polypropylene, utilize petroleum-based monomers in general, and there is a problem in that degradability in the natural state is poor and adversely affects the environment when disposed of 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, especially when environmental issues are important, and research and development of eco-friendly materials that can replace petroleum-based resins are 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, in biodegradable polyester, when the ester functional group is exposed to external water and air, hydrolysis occurs to enable biodegradation. Examples of such polyesters include polybutylene adipate terephthalate (PBAT), poly butylene succinate (PBS), and poly lactic acid (PLA).

However, these biodegradable polyesters are inferior to petroleum-based resins in terms of mechanical properties, commercial value or commodity, and price competitiveness. In particular, there are problems in that mechanical properties, such as tensile strength and tear strength, are very inferior to petroleum-based resins, and research and development to solve them are urgent.

The present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a biodegradable composite having improved mechanical properties and a method for manufacturing the same.

In order to achieve the above object, the present invention provides a biodegradable composite prepared by polymerization including an aliphatic dicarboxylic acid or a derivative thereof, an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diol, and natural polymer nanofibers.

In one example of the present invention, the natural polymer nanofibers are not particularly limited, but may be any one or more selected from nanochitin fibers and nanocellulose fibers.

In an example of the present invention, the content of the natural polymer nanofibers is not particularly limited, but may be 0.005 to 2% by weight relative to 100% by weight of the entire biodegradable composite.

In one example of the present invention, the natural polymer nanofibers are not particularly limited as long as the object of the present invention is achieved, but may have an average diameter of 1 to 200 nm and a length of 100 nm to 100 μm. have.

In one example of the present invention, the biodegradable composite is not particularly limited, but may satisfy the following formula (1).

[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 including the natural polymer nanofibers.

In one example of the present invention, the biodegradable complex is not particularly limited, but may satisfy the following formula (2).

[Equation 2]

In Equation 2, TT ₁ is the tear strength (kgf/cm) of the biodegradable composite, and TT ₀ is the tear strength (kgf/cm) when polymerized without including the natural polymer nanofibers.

In addition, the present invention, preparing a mixture comprising an aliphatic dicarboxylic acid or a derivative thereof, an aromatic dicarboxylic acid or a derivative thereof, and an aliphatic diol,

Dispersing the natural polymer nanofibers in the mixture, and

It provides a method for producing a biodegradable complex, comprising the step of polymerizing the mixture of the natural polymer nanofibers dispersed.

In addition, (A) dispersing the natural polymer nanofibers in an aliphatic diol, and

(B) providing a method for producing a biodegradable complex comprising the step of polymerizing a mixture of the aliphatic diol in which the natural polymer nanofibers are dispersed, an aliphatic dicarboxylic acid or a derivative thereof, and an aromatic dicarboxylic acid or a derivative thereof.

In one example of the present invention, the step (A) may be to disperse the diol by dispersing the natural polymer nanofibers into the aliphatic diol.

The present invention can provide a biodegradable composite and a method for manufacturing the same, in which mechanical properties such as tensile strength, elongation, and tear strength are significantly improved.

In addition, the present invention can provide a method for producing a biodegradable composite, which does not require a pretreatment process for hydrophobization of natural polymer nanofibers, a melt kneading process, a solution mixing process, or the like.

Hereinafter, the present invention will be described in detail.

All terms (including technical and scientific terms) used in this specification may be used in a sense that can be commonly understood by those having ordinary knowledge in the technical field to which the present invention belongs, unless otherwise defined.

In addition, the singular form also includes the plural form unless otherwise specified in the phrase.

The present invention relates to a biodegradable composite, in which mechanical properties such as tensile strength, elongation, and tear strength are significantly improved.

More specifically, the present invention provides a biodegradable composite prepared by polymerization including an aliphatic dicarboxylic acid or a derivative thereof, an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diol, and natural polymer nanofibers.

In the biodegradable composite of the present invention, the above-described constituent components are polymerized from a monomer, and thus, natural polymer nanofibers form uniformly distributed crosslinking points in the biodegradable composite, thereby having significantly improved mechanical properties.

That is, the biodegradable composite of the present invention is not simply a physical mixture of polyester and natural polymer nanofibers. In this case, as can be seen in the comparative example described later, the improvement in mechanical properties is very weak, or rather, there is a problem that can be lowered.

When explaining the biodegradable complex of the present invention in more detail, the aliphatic dicarboxylic acid is not particularly limited, but oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, server acid, azela It may be any one or more selected from acid and sebacic acid.

Further, the aromatic dicarboxylic acid is not particularly limited, but phthalic acid, terephthalic acid, isophthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,8-naphthalene Dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, anthracene dicarboxylic acid and phenanthrene dicarboxylic acid.

In addition, the aliphatic diol is not particularly limited, 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.

In the biodegradable composite of the present invention, the natural polymer nanofibers may mean that they are produced from natural polymer materials present in nature, for example, chitin or cellulose.

That is, the natural polymer nanofiber of the present invention is not particularly limited, but may be any one or more selected from nano chitin fibers and nanocellulose fibers. In addition, it may be manufactured by nanofiberizing chitin or cellulose by physical and chemical methods already known in the art.

The content of the natural polymer nanofibers is 0.005 to 2% by weight, more preferably 0.01 to 1% by weight, and even more preferably 0.05 to 0.5% by weight, based on 100% by weight of the biodegradable composite, to provide a biodegradable composite do. In this case, the biodegradable composite may have excellent mechanical properties, and particularly, when the natural polymer nanofiber has a content range of 0.05 to 0.5% by weight, the biodegradable composite may have significantly improved mechanical properties.

In addition, the natural polymer nanofibers of the present invention is not particularly limited, but may have an average diameter of 1 to 200 nm, more preferably 1 to 100 nm, and even more preferably 1 to 50 nm. In addition, the length may be 100 nm to 100 μm, more preferably 100 nm to 10 μm. In this case, the natural polymer nanofibers have excellent dispersibility, and thus, the biodegradable composite including it in a uniform distribution may have significantly improved mechanical properties.

The biodegradable composite of the present invention is not particularly limited, but may satisfy the following formula (1).

[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 including the natural polymer nanofibers.

In addition, the biodegradable composite of the present invention is not particularly limited, but may satisfy the following formula (2).

[Equation 2]

In Equation 2, TT ₁ is the tear strength (kgf/cm) of the biodegradable composite, and TT ₀ is the tear strength (kgf/cm) when polymerized without including the natural polymer nanofibers.

In addition, the present invention provides a method for producing the biodegradable composite of the present invention described above.

An example of a method for producing a biodegradable complex of the present invention includes preparing a mixture comprising an aliphatic dicarboxylic acid or a derivative thereof, an aromatic dicarboxylic acid or a derivative thereof, and an aliphatic diol, dispersing natural polymer nanofibers in the mixture Step, and polymerizing the mixture of the natural polymer nanofibers dispersed, may include.

The production method according to the present invention is not merely to physically mix polyester and natural polymer nanofibers, but to polymerize the above-described components from the monomer phase. Thus, by dispersing and crosslinking the natural polymer nanofibers uniformly, a biodegradable composite having excellent mechanical properties can be produced.

Another example of a method for preparing a biodegradable composite of the present invention includes: (A) dispersing natural polymer nanofibers in an aliphatic diol, and (B) aliphatic diols dispersing the natural polymer nanofibers, and an aliphatic dicarboxylic acid. Or a mixture thereof, and an aromatic dicarboxylic acid or a derivative thereof may be mixed and polymerized. In this case, the constituent components can be more reliably polymerized from the monomer phase, and natural polymer nanofibers can form more uniformly distributed crosslinking points in the biodegradable complex. Thus, there is an effect that can significantly improve the mechanical properties of the biodegradable composite.

In this case, the step (A) is not particularly limited, but may be to disperse the diol by dispersing the natural polymer nanofibers into the aliphatic diol. In this case, the above-described effect is further enhanced, and a biodegradable composite having excellently improved mechanical properties can be produced.

In the production method of the present invention, the aliphatic dicarboxylic acid is not particularly limited, but is selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, server acid, azelaic acid and sebacic acid. It can be one or more.

Further, the aromatic dicarboxylic acid is not particularly limited, but phthalic acid, terephthalic acid, isophthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,8-naphthalene Dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, anthracene dicarboxylic acid and phenanthrene dicarboxylic acid.

In addition, the aliphatic diol is not particularly limited, 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.

In the manufacturing method of the present invention, the natural polymer nanofiber is not particularly limited, but may be any one selected from nano chitin fibers and nanocellulose fibers.

In addition, in the production method of the present invention, the amount of natural polymer nanofibers dispersed in the mixture, aliphatic diol or distilled water is 0.005 to 2% by weight, more preferably 0.01 to 1% by weight, based on 100% by weight of the entire biodegradable composite, More preferably, it may be 0.05 to 0.5% by weight. In this case, a biodegradable composite having excellent mechanical properties can be prepared. In particular, in the range of 0.05 to 0.5% by weight, a biodegradable composite having remarkably improved mechanical properties can be prepared.

In addition, the natural polymer nanofibers, although not particularly limited thereto, may have an average diameter of 1 to 200 nm, more preferably 1 to 100 nm, and more preferably 1 to 50 nm. In addition, the length may be 100 nm to 100 μm, more preferably 100 nm to 10 μm. In this case, natural polymer nanofibers may exhibit excellent dispersibility.

In the manufacturing method of the present invention, the method for dispersing the natural polymer nanofibers is not particularly limited, but may be using an ultrasonic generator.

Hereinafter, preferred examples and comparative examples of the present invention will be described. However, the following examples are only preferred examples of the present invention, and the present invention is not limited to the following examples.

[Assessment Methods]

(1) Tensile test: Tensile strength, and elongation were measured according to ASTM D638-Type V using Intstron 5943 equipment. It was measured at 25°C with a load cell of 10 kN and a crosshead speed of 100 mm/min. The average value measured 5 times was obtained.

(2) Tear test: The tear strength was measured according to the test method of KS M ISO 34-1:2009.

[Examples 1 to 4]

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

Subsequently, 1,4-butanediol, adipic acid (0.24 mol, 34.61 g) and dimethyl terephthalate (0.24 mol, 45.99 g) in which nanochitin fibers were dispersed were introduced into a four-neck reactor (500 ml). To this, an overhead stirrer, a nitrogen inlet and a condenser were mounted, stirred at 10 rpm for 1 hour, and purged with nitrogen.

Then, for esterification, the mixture was completely melted by heating to 140° C., and then Ti(OBu) ₄ was added as a catalyst at 500 ppm relative to the total weight of adipic acid and dimethyl terephthalate in the mixture. Then, while stirring at 150 rpm, the reactor was heated to 180°C at a rate of 10°C/min, and then maintained for 2 hours. Then, the temperature was raised to 210° C. and maintained for 2 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, it was heated at a rate of 10°C/min to 240°C, and the stirring speed was maintained at 50 rpm, and adjusted to 100 mTorr or less through gradual decompression. When the viscosity of the internal reactant was increased by measuring the torque through the 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 complex.

The amount of the nano-chitin fiber alone was 0.5 wt% (Example 2), 0.005 wt% (Example 3), and 2.0 wt% (Example 4), respectively, and the above procedure was repeated to further add a biodegradable complex. It was prepared.

Tensile strength, elongation, and tear strength were measured according to the evaluation method for the prepared biodegradable composite, and are shown in Table 1 below.

[Examples 5 to 8]

In Example 1, instead of nanochitin fibers, nanocellulosic fibers were 0.05 wt% (Example 5), 0.5 wt% (Example 6), 0.005 wt% (Example 7), and 2.0 wt% (Example 8), respectively. ), except that it was carried out in the same manner as in Example 1 to prepare a biodegradable complex.

Tensile strength, elongation, and tear strength of the biodegradable composite were measured, and are shown in Table 1 below.

[Example 9]

In Example 1, a biodegradable composite was carried out in the same manner as in Example 1, except that 0.05 wt% of nanochitin fibers were previously dispersed in distilled water (5 ml) and then added to 1,4-butanediol for dispersion. Was prepared.

Tensile strength, elongation, and tear strength of the biodegradable composite were measured, and are shown in Table 1 below.

[Comparative Example 1]

In Example 1, except for not using the nano-chitin fibers, it was carried out in the same manner as in Example 1 to prepare PBAT (poly butylene adipate terephthalate).

Tensile strength, elongation and tear strength of the prepared PBAT were measured, and the results are shown in Table 1 below.

[Comparative Example 2]

First, after PBAT was prepared, 20 wt% of PBAT solution (CHCl ₃ ) was added with a nano-chitin fiber content of 0.05 wt% based on PBAT, and the solution was blended to carry out the same procedure as in Example 1 except for preparing a composite.

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

Nanofiber input
(wt%) The tensile strength
(MPa) Elongation
(%) Tear strength
(Kgf/cm) Example 1 0.05 58 1050 225 Example 2 0.5 55 1010 205 Example 3 0.005 41 870 152 Example 4 2.0 40 820 151 Example 5 0.05 55 1040 218 Example 6 0.5 57 1020 235 Example 7 0.005 41 890 154 Example 8 2.0 39 810 149 Example 9 0.05 65 1190 265 Comparative Example 1 - 35 750 140 Comparative Example 2 0.05 38 790 146

As can be seen in Table 1, in the case of the biodegradable composite of the Examples, it showed excellent mechanical properties. Although this is not certain, it is judged that the effect of forming the crosslinking point having a uniform distribution in the nano-chitin fiber or nano-cellulose fiber by polymerizing the constituent components from the monomer phase.

In particular, the biodegradable composites of Examples 1 to 2 and Examples 5 to 6 exhibited significantly improved mechanical properties.

In addition, in the case of Example 9 in which nano-chitin fibers were previously dispersed in distilled water, and added and dispersed in 1,4-butanediol, a more remarkable improvement in mechanical properties, for example, 10 to 20% or more compared to other examples , More preferably, showed an improvement effect of 60% or more.

On the other hand, as can be seen in Table 1, in the case of PBAT of Comparative Example 1 prepared without containing nano-chitin fibers and nano-cellulose fibers, it exhibited very poor mechanical properties.

In addition, in the case of the composite of Comparative Example 2, in which PBAT was first prepared and then physically mixed with nanochitin fibers through solution blending, the effect of improving mechanical properties was very insignificant.

Claims (9)

A biodegradable composite prepared by polymerization including an aliphatic dicarboxylic acid or a derivative thereof, an aromatic dicarboxylic acid or a derivative thereof, an aliphatic diol, and natural polymer nanofibers,
The natural polymer nanofibers include any one or more selected from nano-chitin fibers and nano-cellulose fibers,
The content of the natural polymer nanofiber is 0.05 to 0.5% by weight relative to the total 100% by weight of the biodegradable complex, biodegradable complex. delete delete According to claim 1,
The natural polymer nanofiber, the average diameter is 1 to 200 nm, the length is 100 nm to 100 ㎛, biodegradable complex. According to claim 1,
The biodegradable complex, which satisfies the following formula 1, biodegradable complex.
[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 including the natural polymer nanofibers. According to claim 1,
The biodegradable complex, which satisfies the following formula 2, biodegradable complex.
[Equation 2]

In Equation 2, TT ₁ is the tear strength (kgf/cm) of the biodegradable composite, and TT ₀ is the tear strength (kgf/cm) when polymerized without including the natural polymer nanofibers. Preparing a mixture comprising an aliphatic dicarboxylic acid or derivative thereof, an aromatic dicarboxylic acid or derivative thereof, and an aliphatic diol,
Dispersing the natural polymer nanofibers in the mixture, and
As a method for producing a biodegradable complex comprising the step of polymerizing the mixture of the natural polymer nanofibers dispersed,
The natural polymer nanofibers include any one or more selected from nano-chitin fibers and nano-cellulose fibers,
The amount of the natural polymer nanofibers dispersed in the mixture is 0.05 to 0.5% by weight relative to the total 100% by weight of the biodegradable composite, a method for producing a biodegradable composite. (A) dispersing the natural polymer nanofibers in an aliphatic diol, and
(B) a method for producing a biodegradable complex comprising the step of polymerizing a mixture of the natural polymer nanofiber dispersed aliphatic diol, an aliphatic dicarboxylic acid or a derivative thereof, and an aromatic dicarboxylic acid or a derivative thereof,
The natural polymer nanofibers include any one or more selected from nano-chitin fibers and nano-cellulose fibers,
The amount of natural polymer nanofibers dispersed in the aliphatic diol is 0.05 to 0.5% by weight relative to the total 100% by weight of the biodegradable composite, a method for producing a biodegradable composite. The method of claim 8,
In the step (A), distilled water in which the natural polymer nanofibers are dispersed is introduced into the aliphatic diol and dispersed, thereby producing a biodegradable complex.