WO2024063176A1 - Procédé de préparation d'une matière plastique composite à base d'acide polylactique (pla), matière plastique composite ainsi préparée et film la comprenant - Google Patents

Procédé de préparation d'une matière plastique composite à base d'acide polylactique (pla), matière plastique composite ainsi préparée et film la comprenant Download PDF

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WO2024063176A1
WO2024063176A1 PCT/KR2022/014197 KR2022014197W WO2024063176A1 WO 2024063176 A1 WO2024063176 A1 WO 2024063176A1 KR 2022014197 W KR2022014197 W KR 2022014197W WO 2024063176 A1 WO2024063176 A1 WO 2024063176A1
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pla
composite plastic
chitin
cellulose
weight
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PCT/KR2022/014197
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English (en)
Korean (ko)
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진정호
김중권
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울산대학교 산학협력단
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Priority claimed from KR1020220119585A external-priority patent/KR20230043744A/ko
Priority claimed from KR1020220119587A external-priority patent/KR20230043745A/ko
Priority claimed from KR1020220119586A external-priority patent/KR20230116655A/ko
Application filed by 울산대학교 산학협력단 filed Critical 울산대학교 산학협력단
Publication of WO2024063176A1 publication Critical patent/WO2024063176A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B15/00—Preparation of other cellulose derivatives or modified cellulose, e.g. complexes
    • C08B15/02—Oxycellulose; Hydrocellulose; Cellulosehydrate, e.g. microcrystalline cellulose
    • C08B15/04—Carboxycellulose, e.g. prepared by oxidation with nitrogen dioxide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
    • C08B37/0006—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid
    • C08B37/0024—Homoglycans, i.e. polysaccharides having a main chain consisting of one single sugar, e.g. colominic acid beta-D-Glucans; (beta-1,3)-D-Glucans, e.g. paramylon, coriolan, sclerotan, pachyman, callose, scleroglucan, schizophyllan, laminaran, lentinan or curdlan; (beta-1,6)-D-Glucans, e.g. pustulan; (beta-1,4)-D-Glucans; (beta-1,3)(beta-1,4)-D-Glucans, e.g. lichenan; Derivatives thereof
    • C08B37/0027—2-Acetamido-2-deoxy-beta-glucans; Derivatives thereof
    • C08B37/003—Chitin, i.e. 2-acetamido-2-deoxy-(beta-1,4)-D-glucan or N-acetyl-beta-1,4-D-glucosamine; Chitosan, i.e. deacetylated product of chitin or (beta-1,4)-D-glucosamine; Derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/02—Fibres or whiskers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/08—Cellulose derivatives
    • C08L1/10—Esters of organic acids, i.e. acylates
    • C08L1/12—Cellulose acetate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L5/00—Compositions of polysaccharides or of their derivatives not provided for in groups C08L1/00 or C08L3/00
    • C08L5/08—Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones

Definitions

  • the present invention relates to a method for manufacturing polylactic acid (PLA)-based composite plastic, composite plastic manufactured therefrom, and a film containing the same. More specifically, to improve the inherent brittleness of PLA material, nanocellulose or nanochitin A method of manufacturing PLA-based composite plastic through Pickering emulsion and twin-screw extrusion processes using nanocellulose or nanochitin modified through chemical and physical methods as a reinforcing material, composite plastics manufactured therefrom, and It is about a film containing this.
  • PLA polylactic acid
  • PLA is derived from plants such as corn starch and is attracting much attention as a material that can replace existing plastics because it has advantages such as biodegradability, non-toxicity, and biocompatibility. Nevertheless, because it has characteristics of brittleness and low thermal stability, its application range is limited, mainly in the medical field, packaging films, and filaments for 3D printers.
  • inorganic nanoparticles and fibers have excellent thermal properties, they have the disadvantage of being difficult to decompose by heat after use of the composite, making recycling difficult.
  • Patent Document 1 proposes providing a PLA nanocomposite material with improved physical properties without requiring a cellulose surface hydrophobization pretreatment process, melt kneading, or solution mixing process.
  • Non-Patent Document 1 contains a report on the physical properties of PLA/cellulose nanocrystal nanocomposites.
  • Cellulose is the most abundant natural polymer on Earth, and not only has properties such as biodegradability and biocompatibility, but its tensile strength is very similar to that of glass fiber and carbon fiber.
  • CNF which has a high aspect ratio and surface area, is used as a reinforcement material, the composite External forces can be effectively distributed.
  • chitin which is another candidate for natural polymers and is the second most abundant material on Earth after cellulose, is biodegradable, non-toxic, and biocompatible like PLA, and has a high aspect ratio and surface area very similar to glass fiber and carbon fiber. has
  • the cellulose or chitin component may aggregate due to the hydroxyl group (-OH) of the cellulose or chitin, which may have a negative effect on the mechanical properties.
  • Methods for producing composites include dispersing the reinforcement in the matrix using a solvent and extrusion.
  • PLA does not dissolve in water due to its hydrophobicity, so a water dispersion system cannot be applied, and PLA cannot be used in general organic solvents. Because it is insoluble, extrusion is mainly used to produce a composite composed of PLA and cellulose or chitin.
  • the present inventors introduced Pickering emulsion and twin-screw extrusion processes using cellulose or chitin surface-modified through chemical and physical methods as a reinforcing material, and introduced a hydrophobic PLA solution and a twin-screw extrusion process.
  • the cellulose or chitin acts as a surfactant to prepare a stable emulsion solution, and provides a PLA-based composite plastic by uniformly dispersing cellulose or chitin in the PLA matrix.
  • the present invention was completed by confirming the excellent mechanical strength (in particular, improved elongation and toughness) of the composite plastic.
  • One object of the present invention is to provide a method for manufacturing PLA-based composite plastics based on the Pickering emulsion method and twin-screw extrusion process to composite hydrophobic PLA and hydrophilic cellulose or chitin nanofibers.
  • Another object of the present invention is to provide a PLA-based composite plastic with excellent mechanical properties and a film containing the same.
  • the present invention mixes a biodegradable polymer solution containing PLA dissolved in an organic solvent with a dispersion of natural polymers dispersed in an aqueous system to form a water-in-oil (W/O) solution.
  • W/O water-in-oil
  • a method for manufacturing PLA-based composite plastic including a third step of molding the composite material is provided.
  • the Pickering emulsion method in the first step is a method of producing a stabilized emulsion by reducing the interfacial tension at the hydrophobic/hydrophilic interface by using small solid particles instead of a surfactant.
  • a dispersion of natural polymers dispersed in an aqueous system is added to a biodegradable polymer solution containing PLA dissolved in an organic solvent to stabilize it as a water-in-oil (W/O) formulation. It is ordered.
  • W/O water-in-oil
  • based on 100 parts by weight of the polymer solid content in the biodegradable polymer solution containing PLA dissolved in the organic solvent 1 to 3 parts by weight based on the solid content of the natural polymer in the dispersion in which the natural polymer is dispersed in the aqueous system is added to W/O. It is stabilized with a formulation-based emulsion solution.
  • the biodegradable polymer used in the present invention is polylactic acid (PLA) alone or polylactic acid plus polyhydroxyalkanoates (PHA), polybutylene terephthalate (PBAT), and polybutylene.
  • PSA polybutylenesuccinate-coadipate
  • PBSAT polybutylene succinate adipate-co-terephthalate
  • AP aliphatic polyester
  • PES polyethylene succinate
  • PBS polybutylene succinate
  • PBS poly(vinyl alcohol, PVA)
  • poly glycolic acid PGA
  • Polylactic acid-glycolic acid-copolymer Polylactic acid-glycolic acid-copolymer
  • PCL polycaprolactone
  • modified starch resin and thermoplastic starch (TPS).
  • the water-soluble natural polymer complexed as a reinforcing material in the matrix is preferably any one selected from the group consisting of cellulose, chitin, chitosan, dextrin, dextran, glycogen, pullulan, gelatin, and pectin. Specifically, it includes nanofiber or nanocrystal forms of the natural polymer.
  • the dispersion in which the natural polymer is dispersed in an aqueous system is a natural polymer raw material that has been surface modified by succinylation or carboxylation and then pretreated with nanofibers using an ACC (aqueous counter collision) method.
  • ACC aqueous counter collision
  • the surface modification Cellulose nanofibers or surface-modified chitin nanofibers are used.
  • the surface-modified cellulose nanofibers have a diameter of 5 to 7 nm, and the surface-modified chitin nanofibers have a diameter of 5 to 50 nm.
  • the natural polymer is contained in an amount of less than 1 to 3% by weight, and more preferably, the natural polymer is contained in an amount of 1.5 to 2.5% by weight.
  • the present invention provides a PLA-based composite plastic with enhanced mechanical properties consisting of a composite material in which natural polymers are dispersed in a biodegradable polymer matrix containing PLA.
  • the biodegradable polymer and the natural polymer are the same as described in the manufacturing method.
  • the present invention provides a molded article made of the above PLA-based composite plastic.
  • the molded article is an injection molded article; thermally processed products; and a film for extrusion molding or blow molding.
  • the PLA-based composite plastic has excellent mechanical strength (in particular, improved elongation and toughness), molded articles using it can be provided.
  • Figure 1 shows the results of evaluating the properties of cellulose nanofibers according to pretreatment by succinylation in the PLA/cellulose composite plastic manufacturing method of the present invention
  • Figure 2 shows emulsion solutions by cellulose nanofiber content in the PLA/cellulose composite plastic manufacturing method of the present invention
  • Figure 3 is an SEM image of the cross section of the PLA/CNF 2% by weight (Example 6) and PLA/SCNF 2% by weight (Example 3) films in the PLA/cellulose composite plastic manufacturing method of the present invention
  • Figure 4 is a scanning electron microscope image according to the pretreatment of chitin in the PLA/chitin composite plastic manufacturing method of the present invention
  • Figure 5 shows the manufacturing process of the emulsion solution for each formulation of the present invention
  • Figure 6 is a confocal microscopy image at the top, and a confocal microscope image at the bottom for the emulsion solutions of Example 3 and Comparative Example 1 in the production of PLA/cellulose (PLA/SCNF 2% by weight) composite plastic. This is an SEM image of the sheet cross section,
  • Figure 7 is a confocal microscopy image at the top, and a confocal microscope image at the bottom for the emulsion solutions of Example 12 and Comparative Example 2 in the production of PLA/chitin (PLA/SChNF 2% by weight) composite plastic. This is an SEM image of the sheet cross section,
  • Figure 8 shows the mechanical properties results of the PLA/cellulose composite plastic of Figure 6
  • Figure 9 shows the mechanical properties results of the PLA/chitin composite plastic of Figure 7;
  • Figure 10 shows the results of a tensile test on the composite plastic produced by cellulose nanofiber content in the PLA/cellulose composite plastic of the present invention
  • Figure 11 shows the tensile test results for the PLA/cellulose composite plastic of the present invention, produced by cellulose nanocrystal content
  • Figure 12 shows the tensile test results for the composite plastic produced by the content of chitin nanofibers in the PLA/chitin composite plastic of the present invention
  • Figure 13 shows the tensile test results for the PLA+PHA/cellulose composite plastic of the present invention
  • Figure 14 shows the tensile test results for the PLA+PHA/chitin composite plastic of the present invention
  • Figure 15 is an image of a molded article of each composite plastic manufactured according to cellulose or chitin content in the PLA/cellulose composite plastic and PLA/chitin composite plastic of the present invention
  • Figure 16 is an image of a specimen in which a tensile test was performed on PLA/SChNF composite plastic according to chitin content in the PLA/chitin composite plastic of the present invention
  • Figure 17 is a cross-sectional SEM image before the tensile test of the composite plastic manufactured according to the cellulose nanofiber (SCNF) content in the PLA/cellulose composite plastic of the present invention
  • Figure 18 is an SEM image of the fracture surface after the tensile test of Figure 17,
  • Figure 19 is an SEM image of the fracture surface after a tensile test of the PLA/SChNF composite plastic according to the chitin content in the PLA/chitin composite plastic of the present invention
  • Figure 20 shows the melt flow index evaluation results for the PLA-based composite plastic of the present invention.
  • the present invention is a water-in-oil (W/O) formulation based on mixing a biodegradable polymer solution containing PLA dissolved in an organic solvent with a dispersion of natural polymers dispersed in an aqueous system.
  • W/O water-in-oil
  • a method for manufacturing PLA-based composite plastic including a third step of molding the composite material is provided.
  • the Pickering emulsion method in the first step is a method of producing a stabilized emulsion by reducing the interfacial tension at the hydrophobic/hydrophilic interface by using small solid particles instead of a surfactant.
  • the biodegradable polymer is polylactic acid (PLA) alone or polylactic acid plus polyhydroxyalkanoates (PHA), polybutylene terephthalate (PBAT), polybutylene succinate- Adipate (Polybutylenesuccinate-coadipate, PBSA), polybutylene succinate adipate-co-terephthalate (PBSAT), aliphatic polyester (AP), polyethylene succinate (PES) , polybutylene succinate (PBS), polyvinyl alcohol (PVA), poly glycolic acid (PGA), polylactic acid-glycolic acid-copolymer (Poly lactic-co- It is a mixture of any one or two or more selected from the group consisting of glycolic acid (PLGA), polycaprolactone (PCL), modified starch resin, and thermoplastic starch (TPS).
  • PLA polylactic acid
  • PLA+PHA mixture but it is not limited to this and the combination of matrix components made of various biodegrad
  • the biodegradable polymer is hydrophobic and dissolves in an organic solvent, where the organic solvent consists of dichloromethane (DCM), chloroform, ethyl acetate, tetrahydrofuran, and acetone. It is any one selected from the group, and in the examples of the present invention, dichloromethane (DCM) is used as a preferred organic solvent, but is not limited thereto.
  • DCM dichloromethane
  • nanocellulose or chitin is used as a preferred example of a natural polymer, but it is not limited thereto, and any polysaccharide including water-soluble polysaccharides may be selected from the group of known materials.
  • any one selected from the group consisting of chitosan, dextrin, dextran, glycogen, pullulan, gelatin, and pectin is used.
  • the natural polymer includes a nanofiber or nanocrystal form of the material, and preferably, the nanocellulose reacts with cellulose nanofiber (CNF), cellulose nanocrystal (CNC), and succinic anhydride. It may be cellulose nanofibers (SCNF) or surface-modified cellulose nanocrystals (SCNC) surface-modified by succinylation or carboxylation.
  • the dispersion in which the natural polymer is dispersed in an aqueous system is prepared by surface modifying the natural polymer raw material by succinylation or carboxylation and then pretreating it to nanofiber using an ACC (aqueous counter collision) method.
  • ACC aqueous counter collision
  • Figure 1 shows the results of evaluating the properties according to cellulose nanofiber pretreatment in the PLA/cellulose composite plastic manufacturing method of the present invention.
  • (a) is a pure cellulose nanofiber (Pulp) that has not been pretreated, and is not evenly dispersed in the solution and sinks
  • (b) is a cellulose nanofiber surface-modified by succinylation, which is uniformly dispersed but turbid due to its size. It is observed to have a translucent color
  • (c) is a cellulose nanofiber treated with SA and ACC, which is uniformly dispersed in a smaller diameter and size, confirming a stable dispersed phase.
  • the nanocellulose dispersion can be formed by surface modifying the cellulose nanofibers by succinylation or carboxylation and then dispersing them in water.
  • succinylation may be performed by reacting cellulose nanofibers with succinic anhydride (SA).
  • nanocellulose dispersion can be formed by surface modifying cellulose nanofibers by succinylation or carboxylation, treating them with an ACC (aqueous counter collision) method to turn them into nanofibers, and then dispersing them in water.
  • ACC aqueous counter collision
  • Figure 2 is a PLA/SCNF emulsion solution prepared containing 1%, 2%, and 3% by weight of cellulose nanofibers (SCNF) in the PLA/cellulose composite plastic manufacturing method of the present invention
  • Figure 3 is a PLA/CNF emulsion solution.
  • SA succinylation
  • the cellulose nanofibers may be nanofibers having a diameter of about 1 to 10 nm. If the diameter of the cellulose nanofibers exceeds 10 nm, it is difficult to effectively suppress phase separation of the emulsion solution, so the stabilized emulsion Problems may arise in preparing the solution. Therefore, preferably, the surface-modified cellulose nanofibers of the present invention may have a diameter of about 5 to 7 nm.
  • the chitin nanofibers may be nanofibers having a diameter of 5 to 50 nm, and when the diameter of the chitin nanofibers exceeds 50 nm, phase separation of the emulsion solution ( There is a problem that it is difficult to effectively suppress phase separation.
  • Figure 4 is a scanning electron microscope image according to the pretreatment of chitin in the PLA/chitin composite plastic manufacturing method of the present invention. Specifically, (a) is raw ChNF, (b) is SChNF that has undergone succinylation, and (c) is SChNF that has finally undergone nanofiberization through ACC, and is finally uniformly produced after surface modification and nanofiberization through succinylation. SChNF can be identified with a diameter of about 5 to 20 nm.
  • the emulsion solution may be prepared through a Pickering emulsion method.
  • the Pickering emulsion method is a method of producing a stabilized emulsion by reducing the interfacial tension at the hydrophobic/hydrophilic interface using small solid particles instead of surfactants.
  • the nano cellulose acts as a surfactant at the interface between the hydrophobic PLA solution and the hydrophilic nano cellulose aqueous dispersion, so that a stable emulsion solution can be prepared, and thus the PLA and cellulose nanofibers It can be complex.
  • Figure 5 shows the manufacturing process of the emulsion solution for each formulation of the present invention. Regardless of the formulation, the natural polymer mixing ratio is applied to the biodegradable polymer solution containing PLA the same, but the amount of water and organic solvent as the solvent is adjusted. The emulsion formulation is determined by the control.
  • a dispersion of the natural polymer in an aqueous system is added to 100 parts by weight of a biodegradable polymer solution containing PLA dissolved in the organic solvent to produce water-in-oil ( It is stabilized with an emulsion solution based on a water-in-oil (W/O) formulation.
  • W/O water-in-oil
  • Figure 6 shows the emulsion solutions of Example 3 (W/O formulation) and Comparative Example 1 (O/W formulation) in the production of PLA/cellulose (PLA/SCNF 2% by weight) composite plastic.
  • the top is a confocal microscope view ( Confocal microscopy) image
  • the bottom is the SEM image result of the cross section of the sheet after completely drying the solvent
  • Figure 7 shows Example 12 (W/O formulation) in the production of PLA/chitin (PLA/SChNF 2% by weight) composite plastic.
  • the PLA/DCM solution produced a spherical fluorescent SCNF dispersion or SChNF dispersion.
  • the fluorescent SCNF dispersion or SChNF dispersion surrounded the black spherical PLA/DCM solution and had a shape. It is observed as an inverted structure.
  • Figures 8 and 9 show the results of mechanical properties of the PLA/cellulose composite plastic and PLA/chitin composite plastic.
  • water-in-oil (water-in-oil) Composite plastics obtained from emulsion solutions based on oil, W/O) formulations have significantly improved mechanical properties of composite plastics through hydrogen bonding with PLA by uniformly dispersing cellulose nanofibers or chitin nanofibers in the PLA matrix and complexing them. You can check it.
  • Figures 10 to 12 show the results of tensile tests on composite plastics produced according to the content of natural polymer (cellulose nanofibers or chitin nanofibers) in the method for producing PLA-based composite plastics of the present invention.
  • PLA/cellulose composite plastics PLA/SCNF, PLA/SCNC
  • the elongation increases by at least about 5 times and at most about 24 times, especially for PLA/chitin.
  • Composite plastic PLA/SCHNF composite plastic
  • the content of natural polymer is preferably less than 1 to 3 weight. More preferably, it contains 1.5 to 2.5% by weight, and most preferably, it contains 2.0% by weight.
  • the mechanical properties of PLA can be controlled depending on the content of natural polymers (cellulose nanofibers or chitin nanofibers).
  • Figure 13 shows the tensile test results for the PLA + PHA / cellulose 2% by weight composite plastic of the present invention, and compared to the PLA / cellulose 2% by weight composite plastic, it can be seen that the mechanical strength is significantly increased.
  • Figure 14 shows the tensile test results for the PLA + PHA / chitin 2% by weight composite plastic of the present invention.
  • PLA + PHA / chitin 2% by weight composite plastic When compared with the PLA / chitin 2% by weight composite plastic, it can be seen that excellent mechanical strength is still maintained. .
  • the drying performed in the second step can be any drying method such as natural drying, hot air drying, and freeze drying, and the present invention does not specifically limit the drying method.
  • the drying may be done by casting the emulsion solution on a substrate.
  • the composite material may be additionally subjected to a pulverization step to facilitate the twin-screw extrusion process.
  • the composite material can be ground into pieces less than about 5 mm long.
  • Molding in the third step may be performed as a twin-screw extrusion process using a twin-screw extruder.
  • Twin-screw extrusion is a method of forming products by heating and fluidizing materials using two screws and continuously extruding them. It has the advantage of being able to stably extrude heat-sensitive materials as extrusion is possible even at low temperatures.
  • the present invention provides a PLA-based composite plastic with enhanced mechanical properties by uniformly dispersing natural polymers in a biodegradable polymer matrix containing PLA.
  • Figure 15 is an image of a molded article of the PLA-based composite plastic of the present invention, manufactured by the content of cellulose or chitin as a natural polymer in PLA, showing the same tendency of color changing as the cellulose or chitin content increases. You can check it.
  • Figure 16 shows an image of a specimen in which a tensile test was performed on a PLA/chitin composite plastic according to the chitin content among the PLA-based composite plastics of the present invention, showing a specimen containing 2% by weight of SChNF.
  • composite plastic it can be confirmed with the naked eye that it is a material with a significantly higher elongation rate than composite plastic containing 1% by weight and 3% by weight.
  • Figure 17 is a cross-sectional SEM image of the PLA/cellulose composite plastic of the present invention prepared according to the cellulose nanofiber (SCNF) content before the tensile test
  • Figure 18 is an SEM image of the fractured surface after the tensile test of Figure 17. represents.
  • Figure 19 is an SEM image of the fracture surface after a tensile test of the PLA/CHNF composite plastic according to the chitin content in the PLA/chitin composite plastic of the present invention.
  • the cross section is smooth, whereas the fracture surface of the PLA/ShCNF composite plastic is A very rough surface can be seen.
  • the PLA-based composite plastic introduces natural polymers as reinforcing materials to improve the mechanical strength of the PLA material.
  • the reinforcing materials are uniformly dispersed in the PLA material and composited. , It has the characteristics of improving elongation and toughness, realizing a reinforcing effect, so molded articles using it can be provided.
  • the present invention provides a molded article made of PLA-based composite plastic with excellent mechanical properties.
  • the PLA-based composite plastic can be easily applied in the fields of packaging, 3D printing materials, structural lightweight composite materials, and medical technology.
  • Injection molded products from the PLA-based composite plastic thermally processed products; And it is possible to provide any one molded article selected from the group consisting of a film for extrusion molding or blow molding.
  • Figure 20 shows the melt flow index evaluation results for the PLA-based composite plastic of the present invention.
  • MFI of polymers commonly used as blown film products is usually 1 to 10, 2 weight of PLA/SCNF
  • the PLA-based composite plastic of the present invention can be applied as a film, more preferably as a blown film.
  • PLA used the 3D870 product from NatureWorks (USA). Hardwood kraft pulp was supplied as a 1% by weight dispersion from CNNT Co., Ltd. Succinic anhydride (SA) is from Daejeong Chemical, dimethylformamide (DMF), pyridine, sodium hydroxide (NaOH), and dichloromethane (DCM) are from Sigma-aldrich. Purchased. Homogenizer (IKA, T25) and Ultrasonicator (SONICS, vibra cell VCX 500) were used to complex PLA and CNF by forming a Pickering emulsion. The twin screw extruder (TSE) and injection molding machine used to produce composite plastic using composite materials used SJZS-10B equipment from Wuhan Ruiming, China.
  • SA Succinic anhydride
  • DMF dimethylformamide
  • DCM sodium hydroxide
  • DCM dichloromethane
  • the twin-screw extruder is a corotating type in which a pair of screws rotate, and the length to diameter ratio (L/D) is 40.
  • the heater was divided into four sections from the sample hopper to the final extrusion port, each set at 180-185-190-195°C.
  • the temperature of the injection molding machine was 195°C and the pressure was 10 MPa.
  • Step 1 Surface modification and nanofiberization of CNF (manufacturing of SCNF)
  • a PLA solution containing 5% by weight of PLA dissolved in DCM and a SCNF dispersion with a concentration of 1% by weight were prepared.
  • the SCNF dispersion was mixed and stabilized as an emulsion solution to be 1% by weight, 1.5% by weight, 2% by weight, 2.5% by weight, and 3% by weight, respectively, relative to the total PLA of the PLA solution.
  • a stabilized emulsion can be prepared by reducing the interfacial tension at the hydrophobic/hydrophilic interface by using small solid particles instead of a surfactant.
  • the emulsion solution was treated with a homogenizer and a sonicator for 2 minutes and 1 minute, respectively, to prepare an emulsion solution. Then, the emulsion solution was casted in a glass petri dish and both the organic solvent and water were dried to prepare a composite material. The dried composite material was pulverized into pieces about 3 to 5 mm long using a blender, and final composite was performed using TSE equipment to produce PLA/SCNF composite plastic.
  • PLA/CNF composite plastic was prepared in the same manner as in Example 1, except that a CNF dispersion containing 2% by weight of CNF was added to a PLA solution containing 5% by weight of PLA dissolved in DCM.
  • SCNC Succinylated Cellulose Nanocrystal
  • an emulsion was created by mixing a PLA solution containing 5% by weight of PLA dissolved in DCM and a 1% by weight SCNF dispersion at a concentration of 2% by weight of SCNF compared to the dissolved PLA.
  • a solution was prepared, except that 100 ml of the PLA solution and 200 ml of the SCNF dispersion were mixed and stabilized as an emulsion solution of an oil-in-water (O/W) formulation. The same procedure as 1 was performed.
  • Step 1 Surface modification and nanofiberization of chitin nanofibers (manufactured by SChNF)
  • Chitin and pyridine are added to DMF in which succinic anhydride (SA) is dissolved, and then reacted while heating at a temperature of 120°C for 6 hours. Afterwards, the chitin was completely washed with deionized water and ethanol using a centrifuge, and the chitin dispersion was neutralized with NaOH solution to prepare a surface-modified chitin dispersion. The surface-modified chitin was finally nanofiberized (SChNF) by the ACC system (CNNT CO., Ltd., Korea).
  • SA succinic anhydride
  • Step 2 Preparation of PLA/chitin nanofiber composite plastic (PLA/SChNF)
  • PLA/SChNF composite plastic was manufactured using a combination of the Pickering emulsion method and TSE equipment.
  • a PLA solution containing 5% by weight of PLA dissolved in DCM was prepared, and an SChNF dispersion containing 1% by weight of SChNF was prepared.
  • 5 ml, 10 ml, and 15 ml of SChNF dispersion were added respectively so that SChNF was 1 wt%, 2 wt%, and 3 wt% compared to PLA dissolved in 200 ml of the PLA solution, and water-in-oil (water-in-oil) was added.
  • -oil, W/O) formulation was stabilized with a Pickering emulsion solution.
  • the emulsion solution was treated with a homogenizer and a sonicator for 2 minutes and 1 minute, respectively, to prepare an emulsion solution. Then, the emulsion solution was casted in a glass petri dish and both the organic solvent and water were dried to prepare a composite material. The dried composite material was pulverized into pieces about 3 to 5 mm long using a blender, and final composite was performed using TSE equipment to produce PLA/SChNF composite plastic.
  • PLA/ChNF composite plastic was prepared in the same manner as Example 1, except that a PLA solution containing 5% by weight of PLA dissolved in DCM and a dispersion containing 2% by weight of ChNF were used.
  • Example 10 In the PLA/SChNF composite plastic manufacturing step of Example 10, a PLA solution containing 5% by weight of PLA dissolved in DCM and a SChNF dispersion with a concentration of 1% by weight were prepared, and 200 ml of the SChNF dispersion was mixed with 100 ml of the PLA solution, The same procedure as Example 1 was performed, except that it was stabilized with an emulsion solution.
  • Figure 1 shows the results of evaluating the properties according to cellulose nanofiber pretreatment.
  • (a) is a pure cellulose nanofiber (Pulp) that has not been pretreated, and it was confirmed that it was not evenly dispersed in the solution and settled
  • (b) is a cellulose nanofiber treated with succinylation (SA), which was uniformly dispersed but varied in size. It was observed that it had a cloudy translucent color.
  • (c) is a cellulose nanofiber treated with SA and ACC, which was uniformly dispersed with smaller diameter and size to form a stable dispersed phase.
  • Figure 2 shows the PLA/SCNF emulsion solutions of Examples 1, 3, and 5 prepared with 1%, 2%, and 3% by weight of cellulose nanofibers (SCNF) in the PLA/cellulose composite plastic manufacturing method of the present invention.
  • SCNF cellulose nanofibers
  • Figure 3 is an SEM image of the cross section of the PLA/CNF 2% by weight (Example 6) and PLA/SCNF 2% by weight (Example 3) films in the PLA/cellulose composite plastic manufacturing method of the present invention, showing cellulose nanofibers (CNF) )
  • SCNF nanofiberization
  • SA succinylation
  • Figure 4 is a scanning electron microscope image according to the pretreatment of chitin in the PLA/chitin composite plastic manufacturing method of the present invention.
  • (a) is raw ChNF
  • (b) is SChNF that has undergone succinylation
  • (c) is SChNF that has finally undergone nanofiberization through ACC. From the above results, surface modification and nanofibers are performed by succinylation or carboxylation. After fiberization, SChNF was finally confirmed to have a uniform diameter of about 5 to 20 nm.
  • Figure 5 shows the manufacturing process of the emulsion solution for each formulation of the present invention. Accordingly, the mechanical properties according to the prepared emulsion formulation were evaluated.
  • Figure 6 is an image of the emulsion solutions of Example 3 and Comparative Example 1 in the production of PLA/cellulose (PLA/SCNF 2% by weight) composite plastic, with the top being an image using a confocal microscope, and the bottom being the solvent. This is an SEM image of a cross section of a completely dried sheet.
  • Confocal microscopy of the emulsion solution can determine the fluorescence characteristics of the dye according to its dissolution in each solvent.
  • the dye Fluorescein
  • DI water distilled water
  • DI water organic solvent
  • DCM organic solvent
  • the emulsion solution of the water-in-oil (W/O) formulation of Example 3 is a spherical fluorescent SCNF dispersion
  • the oil-in-water (O/W) formulation of Comparative Example 1 has a shape in which the fluorescent SCNF dispersion surrounds the black spherical PLA/DCM solution. It is an inverted structure.
  • Example 3 This structure is shown in the SEM image of the cross section of the sheet in which the organic solvent and water are completely dried in FIG. 6.
  • the composite plastic prepared from the emulsion solution of Example 3 has fine spherical cellulose nanofibers uniformly formed within the PLA matrix. While it was in a dispersed form, in the case of Comparative Example 1 (O/W formulation), water was observed in a shape in which dried cellulose wrapped around a spherical PLA as a matrix.
  • Figure 7 is an image using confocal microscopy at the top and a solvent at the bottom for the emulsion solutions of Example 12 and Comparative Example 2 in the production of PLA/chitin (PLA/SChNF 2% by weight) composite plastic. This shows an SEM image of a cross section of a completely dried sheet, confirming the same results as in Figure 2.
  • the composite plastic obtained from an emulsion solution based on a water-in-oil (W/O) formulation has the dispersibility of cellulose nanofibers or chitin nanofibers in the PLA matrix.
  • W/O water-in-oil
  • the improvement in mechanical properties of the composite plastic prepared from the W/O formulation-based emulsion solution supports the uniform dispersion of cellulose nanofibers (SCNF) or chitin nanofibers (SChNF) inside the PLA matrix.
  • SCNF cellulose nanofibers
  • SChNF chitin nanofibers
  • the tensile test results for the PLA/cellulose composite plastics prepared in Examples 1 to 9 are shown in Table 2 below.
  • the tensile test was measured using a universal testing machine (UTM) (AMETEK, LS5, USA), and the specimen was prepared in accordance with ASTM D638.
  • the length was 75 mm, width 6 mm, and thickness 2 mm, and tensile strain was applied at a rate of 1 mm/min.
  • Figures 10 and 11 show tensile test results for PLA/cellulose composite plastics manufactured by cellulose nanofiber or cellulose nanocrystal content.
  • PLA/CNF composite plastic prepared in Example 6 also showed a 19-fold improvement in elongation when it contained 2% by weight of CNF compared to pure PLA.
  • Figure 12 shows the tensile test results for PLA/chitin composite plastic manufactured by chitin nanofiber content.
  • the composite plastic containing 2% by weight of SChNF shows an elongation of 351.8%, which is significantly higher than that of other composite plastics, so the content of SChNF in the PLA matrix is 1 to 3% by weight, more preferably 1.5 to 2.5% by weight. is optimized.
  • the mechanical properties are lowered, which supports the result that in a general composite system, as the amount of reinforcing agent increases, dispersion within the matrix resin becomes more difficult, and thus the mechanical properties decrease. .
  • Example 15 the PLA/ChNF composite plastic prepared in Example 15 also showed 6 times improved elongation compared to pure PLA.
  • PLA+PHA/CNF 2% by weight composite plastic was confirmed to have comparable mechanical properties to the PLA/ChNF 2% by weight composite plastic.
  • Figure 15 is an image of a molded article of each composite plastic manufactured by cellulose or chitin content in the PLA/cellulose composite plastic and PLA/chitin composite plastic of the present invention. As the cellulose or chitin content increases, the color appears darker. The results are expected to be the result of deterioration of cellulose or chitin during the process of extrusion through a twin-screw extruder.
  • Figure 16 is an image of a specimen in which a tensile test was performed on PLA/SChNF composite plastic according to chitin content in the PLA/chitin composite plastic of the present invention, and in the case of composite plastic containing 2% by weight of SChNF, 1% by weight and 3% by weight. It can be confirmed with the naked eye that this material has a significantly higher elongation rate than conventional composite plastic.
  • Figure 17 is a cross-sectional SEM image of the PLA/cellulose composite plastic of the present invention prepared according to the cellulose nanofiber (SCNF) content before the tensile test
  • Figure 18 is an SEM image of the fractured surface after the tensile test of Figure 17. From the results in the above figure, it can be seen that a stable network complexed by the Pickering emulsion process can be formed, and in particular, in the case of PLA/SCNF composite plastic with a SCNF content of 2% by weight compared to PLA, a very dense network can be confirmed.
  • SCNF cellulose nanofiber
  • the fractured surface after the tensile test was confirmed to have a rough surface compared to the clean fractured surface due to the brittle nature of pure PLA, supporting the fact that the SCNF evenly dispersed within the PLA matrix effectively distributes the tensile force.
  • Figure 19 is an SEM image of the fracture surface after a tensile test of the PLA/CHNF composite plastic according to the chitin content in the PLA/Chitin composite plastic of the present invention.
  • Pure PLA has a relatively clean fracture surface, which is a characteristic of brittleness, whereas PLA/ShCNF The fracture surface of the composite plastic was confirmed to have a very rough surface.
  • the melt flow index (MFI) of the PLA-based composite plastic was evaluated.
  • the melt flow index is an important evaluation factor for evaluating fairness in the extrusion process, and is a numerical representation of how easily the molten polymer flows under specific conditions. At this time, if the MFI value does not reach the standard, the molded extrudate lacks melt strength to maintain its shape, making it difficult to extrude the product.
  • Figure 20 shows the melt flow index evaluation results for the PLA-based composite plastic of the present invention.
  • the MFI of polymers usually used as blown film products is usually 1 to 10
  • PLA/SCNF 2% by weight composite By confirming the value of 8.81 for plastic and 1.66 for PLA/ShCNF 2% by weight composite plastic, the PLA-based composite plastic of the present invention can be used as a blown film, etc.

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Abstract

La présente invention concerne un procédé de préparation d'une matière plastique composite à base d'acide polylactique (PLA), une matière plastique composite ainsi préparée, et un film la comprenant. La présente invention utilise de la nanocellulose ou de la chitine en tant que matériau de renforcement afin d'atténuer la fragilité inhérente d'une matière de PLA, disperse de manière stable et uniforme la cellulose ou la chitine, qui est modifiée par des méthodes chimiques et physiques, dans une matrice de PLA par l'intermédiaire d'une émulsion de Pickering et d'une extrusion en extrudeuse à double vis de façon à former un composite, et peut commander les propriétés mécaniques du PLA en fonction de la quantité de matériau de renforcement.
PCT/KR2022/014197 2022-09-21 2022-09-22 Procédé de préparation d'une matière plastique composite à base d'acide polylactique (pla), matière plastique composite ainsi préparée et film la comprenant WO2024063176A1 (fr)

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KR1020220119585A KR20230043744A (ko) 2021-09-24 2022-09-21 Pla/나노 셀룰로오스 복합체의 제조방법, 그로부터 제조된 복합체 및 이를 포함하는 필름
KR1020220119587A KR20230043745A (ko) 2021-09-24 2022-09-21 Pla 기반의 복합플라스틱의 제조방법, 그로부터 제조된 복합플라스틱 및 이를 포함하는 필름
KR10-2022-0119586 2022-09-21
KR1020220119586A KR20230116655A (ko) 2022-01-28 2022-09-21 Pla/키틴 나노섬유 복합체의 제조방법, 그로부터 제조된 복합체 및 이를 포함하는 필름
KR10-2022-0119587 2022-09-21
KR10-2022-0119585 2022-09-21

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060129015A (ko) * 2004-02-10 2006-12-14 다케다 야쿠힌 고교 가부시키가이샤 서방성 제제
US20120283363A1 (en) * 2009-12-11 2012-11-08 Kao Corporation Composite material
CN103341172A (zh) * 2013-05-07 2013-10-09 中国科学院过程工程研究所 一种双孔多糖微球及其制备方法、用途
CN108329490A (zh) * 2018-03-22 2018-07-27 常德市金润新材料科技有限公司 一种聚乳酸/改性纳米纤维素可降解复合阻隔材料的制备方法
CN108504056A (zh) * 2018-03-27 2018-09-07 东华大学 一种制备彩色纳米纤维素/聚乳酸复合薄膜的方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20060129015A (ko) * 2004-02-10 2006-12-14 다케다 야쿠힌 고교 가부시키가이샤 서방성 제제
US20120283363A1 (en) * 2009-12-11 2012-11-08 Kao Corporation Composite material
CN103341172A (zh) * 2013-05-07 2013-10-09 中国科学院过程工程研究所 一种双孔多糖微球及其制备方法、用途
CN108329490A (zh) * 2018-03-22 2018-07-27 常德市金润新材料科技有限公司 一种聚乳酸/改性纳米纤维素可降解复合阻隔材料的制备方法
CN108504056A (zh) * 2018-03-27 2018-09-07 东华大学 一种制备彩色纳米纤维素/聚乳酸复合薄膜的方法

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