KR20130103154A - Polypropylene-polylactic acid mixed resin/graphene/natural fiber bionanocomposite and manufacturing method of thereof - Google Patents

Abstract

PURPOSE: A polypropylene-polylactic acid mixed resin/graphene/natural fiber bionanocomposite is provided to remarkably improve mechanical properties such as tensile strength, flexural strength, and impact strength by uniformly dispersing graphene and natural fiber due to the addition of a compatibilizer. CONSTITUTION: A bionanocomposite includes a polypropylene-polylactic acid mixed resin, a compatibilizer, graphene, and natural fiber. The propylene is selected from a propylene homopolymer, the copolymer of a (C2-18)α-olefin and propylene, or a mixture thereof. The polylactic acid one or more selected from poly-L-lactic acid, poly-D-lactic acid, or poly-L,D-lactic acid each of which number average molecular weight is 10,000-100,000. The compatibilizer is maleic anhydride-grafted-polypropylene. The amount of the maleic anhydride included is 0.1-5.0 wt% with regard to the compatibilizer.

Description

Polypropylene-polylactic acid mixed resin / graphene / natural fiber bionanocomposite and manufacturing method of

The present invention relates to a polypropylene-polylactic acid blend / graphene / natural fiber bionanocomposite and a method for preparing the same, and more specifically, to a bio-nanocomposite by adding graphene and natural fibers to a mixed resin of polypropylene and polylactic acid. In forming the polypropylene-polylactic acid blend / graphene / natural fiber bio which improved the mechanical properties such as flexural strength, tensile strength and impact strength by more uniformly dispersing graphene and natural fiber by adding a compatibilizer. It relates to a nanocomposite and a preparation method thereof.

Polypropylene is one of the representative polymers among general-purpose polymers capable of mass production and excellent processability, and is widely used in daily life as well as industrial applications. Due to the low specific gravity, polypropylene can reduce the weight of the product, has excellent molding processability and chemical resistance, and has excellent mechanical properties such as tensile strength and flexural strength, and excellent thermal properties such as thermal expansion coefficient and high thermal deformation temperature. This is because it has the advantage. However, in spite of various applications, polypropylene has many parts that need improvement of properties in order to be applied to industrial parts including low temperature vulnerability. In addition, these synthetic plastics are notable to be decomposed well, which is the biggest advantage and disadvantage of them, and thus, a serious problem in the global environment due to the problem that the synthetic plastics that are disposed of are not decomposed naturally when landfilled according to a conventional method. Also, in the case of incineration and recycling, which is a conventional treatment method, there is a problem such as generation of harmful substances in the atmosphere during treatment, and there is a disadvantage that the conventional pollution treatment method cannot completely solve the environmental pollution problem.

Recently, as environmental problems have received major attention from around the world, many attempts have been made not only to recycle polypropylene but also to blend biodegradable polymers or natural polymers with general-purpose polymers such as polypropylene to improve their physical properties and environmental friendliness. Is getting. One of these approaches is the development of degradable plastics that make used plastics self-degradable. Biodegradable plastics include microorganism-producing polymers such as polyhydroxybutylate (PHB), polymers using microbial-producing biochemicals as synthetic raw materials, chemically synthesized aliphatic polyesters, natural polymers such as chitin, and plastics containing starch. There are many forms. However, the modified plastics for improving such degradability are inferior in mechanical and thermal properties as compared to conventional plastics, and in addition, inexpensive starch and the like must be mixed in consideration of manufacturing cost, thereby deteriorating transparency and the like. There is a disadvantage that the use range is limited.

Therefore, in order to solve the above-mentioned disadvantages, biodegradation using polylactic acid, which can be manufactured in large quantities inexpensively by fermentation method development and possesses a fast decomposition speed under composting conditions, has expanded the scope of its application field. Castle sheets were provided. For example, Japanese Patent Application Laid-Open No. 1998-120889 (Patent Document 1) has heat resistance as a function to be reinforced in order to commercialize polylactic acid, and a method of blending polyester and other biodegradable resins for improvement thereof. Japanese Laid-Open Patent Publication No. 1999-241008 (Patent Document 2) discloses a composition composed of polylactic acid and an aliphatic polyester having a melting point of 80 to 250 ° C and other natural products, and having a heat resistance of 60 to 120 ° C. Posting what is. However, the sheet using the conventional polylactic acid still has a disadvantage in that it does not sufficiently realize the mechanical strength.

In order to solve the above-mentioned disadvantages of mechanical strength, polypropylene resin, which is a polyolefin resin, is blended with polylactic acid to make it easy to manufacture, and there is no deterioration in workability, and to prepare a biodegradable resin composition having improved mechanical strength and thermal stability. The method is disclosed, for example, "biodegradable polyester resin composition with mechanical strength, flexibility and transparency" of the Republic of Korea Patent Application No. 2003-0039905 (Patent Document 3) "30 to 70 parts by weight of polylactic acid and aromatic -70 to 30 parts by weight of aliphatic polyester, and 10 to 300 parts by weight of polyolefin resin with respect to 100 parts by weight of the mixed composition, wherein the aromatic-aliphatic polyester is characterized in that the aromatic content of 10 to 30 mol% Biodegradable polyester resin composition ". As disclosed in the patent application invention, polyolefin resins represented by polyethylene and polypropylene are excellent in mechanical properties, gloss, heat resistance, transparency, moisture resistance, chemical resistance, etc., and have good molding processability, such as packaging, containers, agricultural materials, automobile parts, and the like. It is one of the most widely used general purpose resins because of its wide application field and low price / performance ratio. Among them, polypropylene has the best mechanical properties among these resins, and the demand is considerable because it is light and easy to process.

However, since the polypropylene having the above excellent properties is a nonpolar polymer and the biodegradable polylactic acid is a polar polymer, these polymers are incompatible with each other, thereby solving the conventional problems as described above. It does not provide a more complete biodegradable sheet that satisfies all of the mutually opposite properties of thermal stability. In order to satisfy all of the mutually conflicting properties, a method of adding a compatibilizer known as the most effective method among industrial methods to increase the compatibility of a polymer blend composed of two incompatible resins is applied. Many studies are in progress. For example, a method of applying a method of adding a compatibilizer to Korea Patent Publication No. 10-2010-0092325 (Patent Document 4) or the like is disclosed. However, the invention through the above methods still has a problem that does not meet the level of mechanical strength applicable to the entire industry.

Japanese Patent Laid-Open No. 1998-120889 Japanese Patent Laid-Open No. 1999-241008 Republic of Korea Patent Application No. 2003-0039905 Republic of Korea Patent Publication No. 10-2010-0092325

The present invention is to solve the conventional problems, in the formation of a bio-nanocomposite by adding graphene and natural fibers to the mixed resin of polypropylene and polylactic acid, by adding a compatibilizer, graphene and natural fibers more uniform The present invention aims to provide a polypropylene-polylactic acid blend / graphene / natural fiber bionanocomposite that is dispersed in such a way that mechanical properties such as flexural strength, tensile strength, and impact strength are remarkably improved.

It is also an object of the present invention to provide a method for producing the polypropylene-polylactic acid blend / graphene / natural fiber bionanocomposite.

According to the present invention for achieving the above object,

Provided is a bionanocomposite comprising a mixed resin of polypropylene and polylactic acid, a compatibilizer, graphene and natural fibers.

The polypropylene is selected from a propylene homopolymer, a copolymer of (C2-C18) α-olefin and propylene, or a mixture thereof, and the polylactic acid has a poly-L-lactic acid, poly-D having a number average molecular weight of 10,000 to 100,000. It is characterized by one or two or more selected from -lactic acid or poly-L, D-lactic acid.

The mixed resin of polypropylene and polylactic acid comprises 20 to 80% by weight of polypropylene and 80 to 20% by weight of polylactic acid, and 0.01 to 30 parts by weight of a compatibilizer based on 100 parts by weight of the mixed resin of polypropylene and polylactic acid. , 0.01 to 20 parts by weight of graphene and 0.01 to 60 parts by weight of natural fibers.

The compatibilizer is polypropylene grafted with maleic anhydride, and the maleic anhydride is included in the compatibilizer in an amount of 0.1 to 5.0 wt%.

The graphene is one or two or more selected from single-walled graphene, multi-walled graphene, graphene oxide, graphene reducing materials and mixtures thereof, the natural fiber is preferably an average length of 0.1 to 50mm Do.

A method for producing a bionanocomposite comprising mixing and extruding 0.01 to 30 parts by weight of a compatibilizer, 0.01 to 20 parts by weight of graphene and 0.01 to 60 parts by weight of natural fiber, based on 100 parts by weight of a mixed resin of polypropylene and polylactic acid. To provide.

According to the polypropylene-polylactic acid mixed resin / graphene / natural fiber bionanocomposite of the present invention and a method for preparing the same, the polypropylene and polylactic acid mixed resin and graphene and natural resin are improved to improve the compatibility of polypropylene and polylactic acid. Graphene and natural fibers may be uniformly dispersed in the mixed resin matrix. The bionanocomposite material in which the graphene and natural fibers of the present invention are uniformly dispersed in the polypropylene and polylactic acid mixed resin matrix has mechanical properties compared to pure polypropylene and polylactic acid mixed resin and commercially available polypropylene and polylactic acid mixed resin. Bio-nano composites with the greatest improvement can be produced.

In addition, it solves the compatibility problems and mechanical properties deterioration when adding a biodegradable polymer for imparting biodegradability (biodegradability), while maintaining the flexibility, chemical resistance and heat resistance of polypropylene, while maintaining biodegradability By the carbon nano material graphene and natural fiber kenaf, mechanical properties are improved, and stability of physical properties is excellent.

This invention can be used in various industrial materials such as interior interior materials for automobiles, interior materials for automobiles, electronic cases, household goods, office supplies, etc. by improving the utilization of materials due to solving the problem of deterioration of properties of biodegradable materials. It is an eco-friendly material that can effectively cope with the effects of carbon dioxide reduction and light weight, and has the advantage of being applicable to various purposes.

Hereinafter, preferred embodiments and physical property measurement methods for polymer-nanoparticles prepared by the production method of the present invention will be described in detail. The present invention may be better understood by the following examples, which are for the purpose of illustrating the present invention and are not intended to limit the scope of protection defined by the appended claims.

The present invention provides a bionanocomposite comprising a polypropylene and polylactic acid mixed resin, a compatibilizer, graphene and natural fibers, wherein the polypropylene is a propylene homopolymer or α having 2 to 18 carbon atoms Polypropylenes of block or irregular copolymers of olefins and propylene can be used.

In addition, the polylactic acid is a known polylactic acid can be used without limitation, in particular one selected from poly-L- lactic acid, poly-D- lactic acid or poly-L, D- lactic acid having a number average molecular weight of 10,000 to 100,000. Or two or more kinds are effective.

If the number average molecular weight of the polylactic acid is less than 10,000 may cause a problem that the biodegradation properties are insignificant, if it is more than 100,000 may cause a problem that the compatibility is too large molecular weight is too large.

The mixed resin of polypropylene and polylactic acid preferably contains 20 to 80% by weight of polypropylene and 80 to 20% by weight of polylactic acid, and more preferably 40 to 60% by weight of polypropylene and 60 to 40% by weight of polylactic acid. It is effective to be.

When the polypropylene is less than 20% by weight, and the polylactic acid is more than 80%, mechanical properties of the bionanocomposite may be lowered, biodegradability may be increased, and stability of the composite may be weakened. If the weight ratio is more than 20% and the polylactic acid is less than 20%, the flexibility and the biodegradability of the composite may be deteriorated.

In addition, the compatibilizer can be used without limitation polyolefin resin grafted maleic anhydride, in particular maleic anhydride graft polypropylene is effective. It is effective for the compatibilizer to comprise 0.1 to 5.0% by weight of maleic anhydride. Since maleic anhydride is included in an optimal content, there is an advantage that the compatibility of the mixed resin of polypropylene and polylactic acid, graphene, and natural fiber can be effectively improved.

It is preferable that the said compatibilizer contains 0.01-30 weight part with respect to 100 weight part of mixed resins, It is effective to contain 1-15 weight part more preferably. When the compatibilizer is less than 0.01 parts by weight, a problem may occur that improves the compatibility of the mixed resin with graphene and natural fibers, and when more than 30 parts by weight, the improvement of the mechanical properties of the composite is minimal. Problems may arise.

In addition, the graphene is preferably one or two or more selected from single-walled graphene, multi-layered graphene, graphene oxide, graphene reducing materials and mixtures thereof. The graphene is added to improve the mechanical properties, it is preferable to include 0.01 to 20 parts by weight, more preferably 0.01 to 10 parts by weight based on 100 parts by weight of the mixed resin. When the graphene is less than 0.01 parts by weight, a problem of insignificant improvement in mechanical properties may occur. When the graphene is more than 20 parts by weight, the compatibility with the mixed resin may be reduced.

In addition, the natural fiber can be used without limitation as long as it is a normal natural fiber containing cellulose, it is particularly effective that at least one selected from wood-based cellulose, starch, Kenaf. The natural fiber is preferably an average length of 0.1 to 50mm, preferably wet or dry milled fiber.

In addition, the natural fiber is preferably included 0.01 to 60 parts by weight, more preferably 1 to 40 parts by weight based on 100 parts by weight of the mixed resin. If the natural fiber is less than 0.01 parts by weight may cause a problem of lowering the mechanical properties and biodegradability, if more than 60 parts by weight may cause a problem that compatibility with the mixed resin is lowered.

In addition, the present invention may further include an additive within a range that does not affect the physical properties of the bio nanocomposite.

The additive is preferably selected from the group consisting of UV absorbers, light stabilizers, antioxidants, heat stabilizers, lubricants, and mixtures thereof, and the types of the additives are universally known to those skilled in the art. It can be easily used by those skilled in the art.

In order to achieve another object of the present invention, the present invention provides a method for producing a bio nanocomposite comprising a commercially available polypropylene and polylactic acid mixed resin, graphene, natural fibers.

More specifically, the present invention provides a method for producing a bio-nanocomposite comprising a mixed resin, a compatibilizer, graphene and natural fibers containing polypropylene and polylactic acid, polypropylene in the polypropylene and polylactic acid mixed resin 20 to 80% by weight and 80 to 20% by weight of polylactic acid, and 0.01 to 30 parts by weight of compatibilizer and 0.01 to 20 parts by weight of graphene and 0.01 to natural fiber based on 100 parts by weight of the polypropylene and polylactic acid polymer blend. Preferably, 60 parts by weight of the mixture is included.

Compounding the mixture by melt blending at a constant processing speed and temperature through a twin screw extruder; And pelletizing the extruded strand to 1-50 mm; And processing by compression molding.

In addition, the natural fiber is washed with a solvent containing water, alcohol for 1 to 24 hours; And it characterized in that it comprises a step of preparing for drying for 6 to 72 hours at 30 ~ 100 ℃. In the washing step, the solvent may be water, water-soluble lower alcohol, and an organic solvent which can be easily used by those skilled in the art, and are not particularly limited.

In addition, the internal temperature of the twin-screw extruder is 130 to 220 ℃, the rotational speed is 40 to 250rpm, characterized in that consisting of a feed rate is 0.5 to 10kg / hr.

In addition, the compression molding conditions are carried out for 10 to 80 minutes at 130 to 250 ℃ and 1 to 60000 psi, characterized in that it comprises a degassing process to remove the internal bubbles.

The bionanocomposite prepared by the above production method may obtain a bionanocomposite having a bending strength of 30000 to 50000kgf / cm 2, a tensile strength of 55 to 80MPa, and an impact strength of 30 to 50J / m.

The physical property measurement method of the bionanocomposite according to the Examples and Comparative Examples of the present invention will be described in detail, and the measurement results are shown in Table 1 below.

Property measurement

1) Flexural modulus measurement

 Flexural modulus was measured by the universal testing machine (UTM) (MTS System Co., MTS 810 System) in accordance with ASTM D 790-07.

2) Tensile strength

Tensile strength specimens were prepared at 63 mm x 9 mm x 3 mm in height, respectively, and the tensile strength was measured using a universal testing machine at room temperature according to ASTM D-638. At this time, the cross-head speed of the universal testing machine was 5 mm / min, the length of the gauge was set to 50 mm.

3) impact strength

Impact strength specimens were prepared at 75 mm x 12.5 mm x 3 mm in height, respectively, and were measured by v-notched Izod method at room temperature according to ASTM D-256.

[material]

1) Polypropylene (hereinafter PP)

It is a product supplied by SK Chemicals of Korea, and the brand name is YUPLENE H360F. Specific properties and analytical specifications of the product are as follows:

Melt Index: 12.0 g / 10 min ASTM D-1238

Vicat Softening Point: 154 ° C ASTM D-1525

Tensile Yield Strength: 380 kgf / cm² ASTM D-638

Notched Izod Impact Strength (23 ° C): 4.0 kgfcm / cm ASTM D-256

Flexural Modulus: 16000 kgf / cm² ASTM D-D790

2) polylactic acid (hereinafter PLA):

The product was supplied by NatureWorks LLC in the US under the trade name Ingeo Biopolymer 4032D. Specific properties and analytical specifications of the product are as follows:

Density: 1.24 g / cc ASTM D-1505

Tensile Strength: 15 kpsi (MD) 21 kpsi (TD) ASTM D-882

Melting Point: 155-170 ℃ ASTM D-3418

3) Maleic Anhydride Graft Polypropylene (hereinafter MAPP):

This product was supplied by Honam Petrochemical Co., Ltd. in Korea and its trade name is ADPOLY BP-401. Specific properties and analytical specifications of the product are as follows:

Vicat Softening Point: 123 ℃ ASTM D-1525

Density: 0.90 g / cm ³ ASTM D-1505

Melt Index: 4.0 ~ 6.0 g / 10 min ASTM D-1238

Yield stress: 230 kgf / cm ² ASTM D-638

4) Graphene (hereinafter, GNS):

HC-598 product of Hyundai Coma, Korea was used as a pretreatment.

5) Kenaf fiber (hereinafter referred to as NF):

A low-density (1.42 g / cm ³ ) Kenyan fiber from Bangladesh, consisting of 45-57% cellulose, 21-23% hemicellulose, 8-13% lignin and others (peptin, wax).

[ Example  One] MAPP 6 parts by weight , GNS 1 part by weight , NF 10 parts by weight  1: 1 PP Of PLA

Dry NF to 50 mm and wash with water and alcohol for 24 hours. PP, PLA, MAPP, GNS and washed NF are dried for 24 hours in a vacuum oven at 70 ° C. Mixed resin mixed 500g of dried PP and PLA in a 1: 1 ratio, 6 parts by weight of MAPP, 1 part by weight of GNS and 10 parts by weight of NF, respectively, with a rotating speed of 60 rpm and a temperature inside the extruder. Compounds are melt blended at profiles 120, 140, 180 ° C. and feed rates of 2 kg / hr. Pelletizing step of cutting the extruded strand discharged to 10 mm. The pellets were press-molded at 180 ° C. and 5 to 40000 psi for 50 minutes, including a pressure-defoaming process to remove internal bubbles during processing, to prepare a bionanocomposite material.

[ Example  2] MAPP 6 parts by weight , GNS 1 part by weight , NF 30 weight parts  1: 1 PP Of PLA

Except that the NF is 30 parts by weight, a bio nanocomposite material was prepared in the same manner as in Example 1.

[Example 3] - MAPP 6 parts by weight , GNS 1 part by weight , NF 50 parts by weight of 1: 1 PP / PLA Except for 50 parts by weight of NF, a bionano composite was prepared in the same manner as in Example 1.

[ Example  4] - MAPP 6 parts by weight , GNS 3 parts by weight , NF 10 parts by weight  1: 1 PP Of PLA

Except for 3 parts by weight of the GNS, a bionano composite was prepared in the same manner as in Example 1.

[ Example  5] - MAPP 6 parts by weight , GNS 3 parts by weight , NF 30 weight parts  1: 1 PP Of PLA

Except for 30 parts by weight of NF, a bionano composite was prepared in the same manner as in Example 4.

[ Example  6]- MAPP 6 parts by weight , GNS 3 parts by weight , NF 50 parts by weight  1: 1 PP Of PLA

Except for 50 parts by weight of NF, a bionano composite was prepared in the same manner as in Example 4.

[Example 7] - MAPP 6 parts by weight , GNS 5 parts by weight , NF 10 parts by weight of 1: 1 PP / PLA Except for 5 parts by weight of the GNS, a bionano composite was prepared in the same manner as in Example 1.

[ Example  8] - MAPP 6 parts by weight , GNS 5 parts by weight , NF 30 weight parts  1: 1 PP Of PLA

Except for 30 parts by weight of NF, a bionano composite was prepared in the same manner as in Example 7.

[ Example  9]- MAPP 6 parts by weight , GNS 5 parts by weight , NF 50 parts by weight  1: 1 PP Of PLA

Except for 50 parts by weight of NF, a bionano composite was prepared in the same manner as in Example 7.

PP / PLA Polymer Blend of Comparative Examples 1-7: 3

In Example 1, a polymer blend material was prepared in the same manner as in Example 1, except that the blend of MAPP, GNS, and NF was 7: 3 polymer blend of 700 g of PP and 300 g of PLA.

Comparative Example 2-PP / PLA Polymer Blend of 1: 1

A polymer blend material was prepared in the same manner as in Comparative Example 1, except that 500 g of 1: 1 polymer blend of PP and PLA was used.

PP / PLA Polymer Blend of Comparative Examples 3-3: 7

A polymer blend material was prepared in the same manner as in Comparative Example 1 except for the 3: 7 polymer blend of 300 g of PP and 700 g of PLA.

Comparative Example 4 PP / PLA Polymer Blend of 7: 3 with MAPP 1.5 parts by weight

In Example 1, the polymer blend material was manufactured in the same manner as in Example 1, except that GNS and NF were mixed, and the mixture was 1.5 parts by weight of MAPP, 700 g of PP, and 300 g of PLA.

Comparative Example 5-1: 1 PP / PLA Polymer Blend with 1.5 parts by weight of MAPP

A polymer blend material was prepared in the same manner as in Comparative Example 4, except that 500 g of 1: 1 polymer blend of PP and PLA was used.

Comparative Example 6-PP / PLA Polymer Blend of 3: 7, 1.5 parts by weight of MAPP

A polymer blend material was prepared in the same manner as in Comparative Example 4, except that the polymer blend was a 3: 7 polymer blend of 300 g of PP and 700 g of PLA.

Comparative Example 7 PP / PLA Polymer Blend of 7: 3, 3 parts by weight of MAPP

Except for 3 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 4.

Comparative Example 8-1: 1 PP / PLA Polymer Blend with 3 parts by weight of MAPP

Except for 3 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 5.

Comparative Example 9 PP / PLA Polymer Blend of 3: 7, 3 parts by weight of MAPP

Except for 3 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 6.

Comparative Example 10 PP / PLA Polymer Blend of 7: 3 by 4.5 MAPP Parts

Except for 4.5 parts by weight of MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 4.

Comparative Example 11-1: 1 PP / PLA Polymer Blend with 4.5 parts by weight of MAPP

Except for 4.5 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 5.

Comparative Example 12-PP / PLA Polymer Blend of 3: 7, 4.5 parts by Weight of MAPP

Except that the MAPP 4.5 parts by weight, a polymer blend material was prepared in the same manner as in Comparative Example 6.

Comparative Example 13-PP / PLA Polymer Blend of 7: 3 by MAPP 6 parts by weight

Except for 6 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 4.

Comparative Example 14-PP / PLA Polymer Blend of 1: 1 by MAPP 6 parts by weight

Except for 6 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 5.

Comparative example  15 - MAPP 6 parts by weight  3: 7 PP Of PLA  Polymer Blend

Except for 6 parts by weight of the MAPP, a polymer blend material was prepared in the same manner as in Comparative Example 6.

Comparative example  16- GNS 1 part  1: 1 PP Of PLA  Polymer Composites

In Example 1, a polymer composite material was manufactured in the same manner as in Example 1, except that MAPP and NF were not mixed.

Comparative example  18 - GNS 5 parts by weight  1: 1 PP Of PLA  Polymer Composites

Except for 5 parts by weight of the GNS, a polymer composite material was prepared in the same manner as in Comparative Example 16.

Comparative example  19 - MAPP  One. 5 parts by weight , GNS 1 part  1: 1 PP Of PLA  Polymer Composites

In Example 1, a polymer composite material was manufactured in the same manner as in Example 1, except that 1.5 parts by weight of MAPP was not mixed with NF.

Comparative example  21- MAPP  One. 5 parts by weight , GNS 5 parts by weight  1: 1 PP Of PLA  Polymer Composites

Except for 5 parts by weight of the GNS, a polymer composite material was prepared in the same manner as in Comparative Example 19.

Comparative example  22 - MAPP 3 parts by weight , GNS 1 part  1: 1 PP Of PLA  Polymer Composites

Except that 3 parts by weight of the MAPP, a polymer composite material was prepared in the same manner as in Comparative Example 19.

Comparative example  24 - MAPP 3 parts by weight , GNS 5 parts by weight  1: 1 PP Of PLA  Polymer Composites

Except for 3 parts by weight of the MAPP, a polymer composite material was prepared in the same manner as in Comparative Example 21.

Comparative example  25 - MAPP  4. 5 parts by weight , GNS 1 part  1: 1 PP Of PLA  Polymer Composites

Except that the MAPP 4.5 parts by weight, a polymer composite material was prepared in the same manner as in Comparative Example 19.

Comparative example  27 - MAPP  4. 5 parts by weight , GNS 5 parts by weight  1: 1 PP Of PLA  Polymer Composites

Except that the MAPP 4.5 parts by weight, a polymer composite material was prepared in the same manner as in Comparative Example 21.

Comparative example  31 - MAPP 6 parts by weight , NF 10 parts by weight  1: 1 PP Of PLA  Polymer Composites

In Example 1, except that GNS was not mixed, a polymer composite material was prepared in the same manner as in Example 1.

[Table 1]

[Table 2]

The sample names of the bionanocomposite materials according to the composition ratio of PP (P), PLA (L), MAPP (M), GNS (G) and NF (F) are the same as the sample names of Tables 1 and 2. The x values correspond to the composition ratios of the letters immediately preceding the alphabet, respectively, and the composition ratios are weight parts by weight of the PP and PLA polymer blends.

Figure 1 shows the flexural modulus of the PP / PLA blend for each composition according to the MAPP content of Comparative Examples 1 to 15. The flexural modulus of PP was about 18000 Kg _f / cm ² , the flexural modulus of PLA was about 34000 Kg _f / cm ^2, and the average graft rate of maleic anhydride of MAPP was about 0.5 wt%. Flexural modulus of PP / PLA blends by composition shows many changes depending on MAPP content. When the composition ratio of PP and PLA is 5: 5, the flexural modulus shows an increase in the flexural modulus error range of PP, and the largest is when the content of MAPP is 6 wt% (P5L5Mx, x = 6) compared to the blend. It was confirmed that the maximum value closest to the flexural modulus value of PLA was shown. On the other hand, blends with a composition ratio of 7: 3 PP and PLA (P7L3Mx) showed the lowest physical properties regardless of MAPP content, which may be attributed to the sample with the lowest PLA content. On the other hand, the addition of more than 3 parts by weight of MAPP can be seen that the flexural modulus slightly decreased, which is MAPP does not play a role as a compatibilizer for uniformly mixing a relatively large amount of PP and a small amount of PLA MAPP Due to the PP skeleton, which accounts for most of the structure, it is thought to be due to gradually returning to the basic flexural modulus value of PP. In the case of the blend of PP and PLA with a composition ratio of 3: 7 (P3L7Mx), although the initial value is close to PLA, it can be seen that the deviation of the error range is very large. This may be because the initial flexural modulus of the blend is large due to the relatively large amount of PLA composition, but because the blend components are not uniformly mixed due to the absence of MAPP, stability against external load is not obtained. In addition, as the flexural modulus decreases slightly with increasing MAPP content, but slightly increases at 6 parts by weight of MAPP, such as the phenomenon of returning to the basic physical properties of PP at the blend ratio of 7: 3 (P7L3Mx). It could be seen that the role of the compatibilizer is not sufficient. Therefore, it was confirmed that the composition of the PP and PLA blends, which are the basic ingredients, for producing the bionanocomposite material was 5: 5, and the MAPP content of the compatibilizer was 6 parts by weight (P5L5Mx, x = 6).

Among the MAPP content ratios, PP / PLA 5: 5 blend (P5L5Mx, x = 6) containing 6 parts by weight of MAPP had the best flexural modulus even when additional graphene was added (P5L5M6Gx). Indicated. However, when adding more than 3 parts by weight of graphene showed a decrease in physical properties. This is because the matrix of the PP / PLA / MAPP blend, which contains both relatively hydrophobic PP and hydrophilic PLA, is commercialized by MAPP containing both functional groups, as discussed above. In addition, graphene contains about 4% of hydrophilic oxygen functional groups, which can be judged not only to increase the original mechanical properties of graphene but also to act as a compatibilizer such as maleic anhydride of MAPP. This indicates that even if graphene is added to the PP / PLA / MAPP blend, the PP / PLA / MAPP and graphene can be uniformly dispersed due to the graphene containing more hydrophilic groups than the MAPP in the matrix. In the case of adding more than 3 parts by weight of graphene, the decrease in physical properties is caused by craze pinning, which increases the fracture toughness of the entire matrix in the region of the filler that is not uniformly dispersed, resulting in a failure in physical properties. It can be considered because it acts as. That is, it was confirmed that the cracks and voids were generated rather than the resistance to craze to facilitate the occurrence of fractures, and the same was confirmed in the flexural modulus of P5L5M4.5Gx. In the flexural modulus of P5L5M0Gx, P5L5M1.5Gx and P5L5M3Gx (particularly P5L5M0Gx), the continual increase in flexural modulus with increasing graphene content is explained above. It also plays a role, and it can be interpreted that graphene reinforces the role of compatibilizer for the relatively insufficient MAPP content.

As a result, the physical properties of all samples improved as the content of natural fibers increased. Among the natural fiber content ratios, PP / PLA / MAPP polymer blend (P5L5M6Gx, x = 3) containing 3 parts by weight of graphene, which had the best physical properties, showed the best flexural modulus even when natural fiber was added (P5L5M6G3Fx). Indicated. However, the addition of more than 30 parts by weight of natural fiber showed a decrease in physical properties. This phenomenon is believed to be due to the fact that MAPP has the property of effectively adhering the hydrophobic PP and the natural fiber of the hydrophilic organic filler. In addition, it can be seen that the natural fibers effectively form the crosslinked structure by the three-dimensional network between the natural fibers, as well as effectively secondary bond with the polymer blend matrix by the cellulose structure, it can be seen that effectively improves the physical properties. However, as in the case of the graphene, when the natural fibers of more than 30 parts by weight of the compound is compounded, the fracture toughness of the entire matrix is increased in the region of the filler which is not uniformly dispersed due to the excessive graphene and the natural fiber filler. The craze pinning phenomenon was applied in the same way, and the flexural modulus gradually decreased.

Tensile strength was measured by the same materials and methods as in the evaluation of the physical properties of the flexural modulus. Each result shows a tendency similar to the result pattern of flexural modulus. The results of tensile strength measurement showed that the results of the above-described flexural modulus change were supplemented and reaffirmed.

The impact strength of PP is about 52 J / m, the impact strength of PLA is about 24 J / m, and the average graft rate of maleic anhydride of MAPP is about 0.5 wt% as above. As shown in the figure, the impact strength of PP / PLA blends by composition varies with MAPP content. When the composition ratio of PP and PLA is 5: 5, the impact strength gradually increases in the range of the impact strength of PLA, and the impact is when the content of MAPP is 6 parts by weight (P5L5Mx, x = 6) relative to the blend. It was confirmed that the strength was the largest and showed the maximum value closest to the impact strength of the PP. On the other hand, blends with a composition ratio of 3: 7 PP and PLA (P3L7Mx) showed the lowest impact strength regardless of MAPP content, which is attributed to the sample with the lowest impact resistance PP than PLA. Can be. For blends with a composition ratio of 7: 3 of PP and PLA (P7L3Mx), although the initial value is close to PP, it can be seen that the deviation of the error range is very large. This may be because the initial impact strength value of the blend is large due to the relatively large amount of PP composition, but because the polymer is not uniformly mixed due to the absence of MAPP, stability against impact cannot be secured. In general, organic fillers show an improvement in the stiffness and thermomechanical resistance of the polymer matrix, similar to the case where the inorganic fillers are added, and the impact strength is reduced in the organic and inorganic fillers. This tendency becomes noticeable as the content of the filler increases. Moreover, almost all fillers, with the exception of glass-fiber reinforced composites, are known to increase thermomechanical resistance but lower impact strength. This phenomenon also appeared in the present invention. Although some materials appear to increase the impact strength depending on the MAPP content, the theoretical and numerical impact strengths of the initial PP and PLA blends, even in the case of composites with the maximum physical properties measured in the present experiment, suggest that The impact strength is very low. In other words, even if the content of MAPP is changed, the role of the compatibilizer does not synergistically enough to strengthen the impact strength of the blend, which means that MAPP alone cannot induce the impact strength. Therefore, considering these results comprehensively, as in the analysis of flexural modulus and tensile strength, the composition of PP and PLA blend, which is the basis for producing bio-nano composites, is 5: 5, and the content of MAPP, a compatibilizer, is 6 parts by weight. It was confirmed that (P5L5Mx, x = 6) was most appropriate based on the stability of the analytical values in consideration of physical properties and deviations.

As a result of the impact strength analysis, it can be seen that the addition of graphene exceeding 3 parts by weight and more than 30 parts by weight of natural fiber showed changes in physical properties similar to the resultant patterns of flexural modulus and tensile strength. Impact strength is generally not expressed as stress at break, like tensile strength, but as the total energy consumed at break or the absorbed break energy per unit length of the sample. The improved physical properties in the impact strength of graphene and natural fiber-filled bionanocomposites are due to the fact that graphene and natural fibers three-dimensionally arranged in a polymer matrix attenuate the impact fracture in the nanocomposite polymer. can do. The Mori-Tanaka method reported in 1973 and many related reports on reinforcing efficiency for nanofillers in polymeric nanocomposites are known. As suggested by the Mori-Tanaka method, it was determined that the mechanical properties were improved according to the three-dimensional random arrangement of the nano-fillers. Since the filler is in the form of nanoplates or nanosheets, the graphene in the present invention having a high aspect ratio has high modulus at E ₁₁ transverse strain, E ₂₂ longitudinal strain, and E ₃ D three-dimensional random strain, respectively. The nanoplate or nanosheet-type fillers having such a high aspect ratio and irregularly arranged three-dimensional arrangement exhibit very high longitudinal, transverse and random strains in the polymer matrix, thereby causing the nanocomposite to exhibit high mechanical properties. It will act as a major factor. In addition, similarly to the above-described effects of increasing the physical properties in flexural modulus and tensile strength, the cellulose structure of the natural fibers effectively secondary bonds with the polymer blend matrix, and also forms a crosslinked structure by a three-dimensional network between the natural fibers. It can be seen that the increase effect. In addition, graphene and natural fiber fillers having a relatively high hydrophilic functional group content as compared to the polymer matrix, as shown in the present invention, minimized the aggregation of the nanofillers as much as possible and improved the interfacial adhesion, thereby improving the mechanical properties. Could.

The results of analyzing the mechanical properties of the present invention are summarized in terms of flexural modulus, tensile strength, and impact strength, and PP / PLA bionanocomposites composited with graphene and natural fibers using MAPP as a compatibilizer. Indicated. The physical properties of flexural modulus, tensile and impact strength of PP / PLA bionanocomposites were improved by about 110%, 46% and 67%, respectively, compared to the PP / PLA blends. It was confirmed that the bionanocomposite material manufactured and processed through the present invention exhibited higher stability.

In the present invention as described above has been described by the specific matters and the specific embodiments and drawings as shown in the specific device diagram, which is provided only to help a more general understanding of the present invention, the present invention is not limited to the above embodiment. For those skilled in the art, various modifications and variations are possible from such description.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (9)

Bionanocomplex including polypropylene and polylactic acid mixed resin, compatibilizer, graphene and natural fiber
The method of claim 1,
The polypropylene is a bionanocomplex selected from a propylene homopolymer, a copolymer of (C2-C18) α-olefin and propylene, or a mixture thereof.
The method of claim 1,
The polylactic acid is one or two or more types of bionanocomplex selected from poly-L-lactic acid, poly-D-lactic acid or poly-L, D-lactic acid having a number average molecular weight of 10,000 to 100,000.
The method of claim 1,
The mixed resin of polypropylene and polylactic acid comprises 20 to 80% by weight of polypropylene and 80 to 20% by weight of polylactic acid, and 0.01 to 30 parts by weight of a compatibilizer based on 100 parts by weight of the mixed resin of polypropylene and polylactic acid. , Bio nano composites containing 0.01 to 20 parts by weight of graphene and 0.01 to 60 parts by weight of natural fibers
The method of claim 1,
The compatibilizer is polypropylene grafted with maleic anhydride,
The maleic anhydride is bio nanocomposite containing 0.1 to 5.0% by weight in the compatibilizer.
The method of claim 1,
The graphene is one or two or more types of bionanocomplex selected from single-walled graphene, multi-walled graphene, graphene oxide, graphene reducing materials, and mixtures thereof.
The method of claim 1,
The natural fiber is a bio nano composite having an average length of 0.1 to 50mm
8. The method according to any one of claims 1 to 7,
The bionanocomposite is a bionanocomposite having a flexural strength of 30000 to 50000kgf / cm2, a tensile strength of 55 to 80MPa, and an impact strength of 30 to 50J / m.
A method for producing a bionanocomposite comprising mixing and extruding 0.01 to 30 parts by weight of a compatibilizer, 0.01 to 20 parts by weight of graphene and 0.01 to 60 parts by weight of natural fiber, based on 100 parts by weight of a mixed resin of polypropylene and polylactic acid. .