A polylactic acid composite material, a preparation method and application thereof

Abstract

This invention discloses a polylactic acid (PLA) composite material, its preparation method, and its applications. The PLA composite material comprises polylactic acid, ramie fiber, nanocellulose, a silane coupling agent, and a plasticizer. The preparation method includes the following steps: dispersing nanocellulose in water to form a nanocellulose dispersion; adding a silane coupling agent to modify the surface of the nanocellulose; adding a plasticizer and mixing thoroughly; adding polylactic acid and ramie fiber and mixing thoroughly; drying; and extruding to obtain the PLA composite material. The PLA composite material of this invention has advantages such as good mechanical properties, good processing flowability, environmental friendliness and biodegradability, and wide availability of raw materials. It is suitable as a 3D printing material for printing various prostheses and medical device molds. Furthermore, its preparation method is simple and its production cost is low, making it suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically to a polylactic acid composite material, its preparation method, and its application. Background Technology

[0002] 3D printing (3DP), also known as additive manufacturing technology (AM), is a technology that manufactures solid parts by adding materials layer by layer based on 3D CAD data. In recent years, 3D printing technology has been widely used in the medical field, such as 3D printing various prostheses and 3D printing molds for various medical devices. As is well known, 3D printing materials are one of the key aspects of 3D printing technology, playing a decisive role in the performance of the printed products. Currently, the base materials commonly used in the medical field are mainly petroleum-based, which inevitably generate a large amount of non-degradable and non-recyclable medical waste, causing serious environmental pollution problems and failing to fully meet the requirements of practical applications.

[0003] Therefore, developing a 3D printing material with good mechanical properties, good processing fluidity, and environmentally friendly biodegradability is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a polylactic acid composite material, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A polylactic acid composite material comprising the following components in parts by weight:

[0007] Polylactic acid: 60-80 parts;

[0008] Ramie fiber: 10 to 30 parts;

[0009] Nanocellulose: 5 to 15 parts;

[0010] Silane coupling agent: 3 to 7 parts;

[0011] Plasticizer: 1 to 3 parts.

[0012] Preferably, the polylactic acid has a number-average molecular weight of 70,000 g / mol to 75,000 g / mol.

[0013] Preferably, the ramie fiber has a length of 45μm to 60μm and a diameter of 10μm to 40μm.

[0014] Preferably, the ramie fiber is prepared by a method comprising the following steps: cutting ramie leaves into pieces, soaking them in an aqueous solution of H2O2-CH2O2-H2SO4, grinding them, filtering them, and drying the solids to obtain ramie fiber.

[0015] Preferably, the molar ratio of H2O2, CH2O2, and H2SO4 in the H2O2-CH2O2-H2SO4 aqueous solution is 1:0.9-1.1:0.15-0.25.

[0016] Preferably, the soaking is carried out at a temperature of 50℃ to 70℃ for a soaking time of 0.5h to 2h.

[0017] Preferably, the drying is carried out at a temperature of 60℃ to 70℃ for a drying time of 0.5h to 2h.

[0018] Preferably, the nanocellulose (NC) is TEMPO CNF.

[0019] Preferably, the length of the nanocellulose is 1 nm to 100 nm and the diameter is 3 nm to 10 nm.

[0020] Preferably, the silane coupling agent is silane coupling agent KH-550.

[0021] Preferably, the plasticizer is polyethylene glycol.

[0022] Preferably, the polylactic acid composite material is in the form of filaments with a diameter of 1.75 mm to 1.95 mm.

[0023] A method for preparing a polylactic acid composite material as described above includes the following steps: dispersing nanocellulose with water to prepare a nanocellulose dispersion, adding a silane coupling agent to modify the surface of the nanocellulose, adding a plasticizer and mixing, adding polylactic acid and ramie fiber and mixing, drying, and extruding to obtain the polylactic acid composite material.

[0024] Preferably, the drying is carried out at a temperature of 55℃ to 65℃ for a drying time of 10h to 20h.

[0025] A 3D printing material comprising the above-mentioned polylactic acid composite material.

[0026] An application of a polylactic acid composite material as described above for the preparation of prostheses or medical device molds.

[0027] The beneficial effects of the present invention are: the polylactic acid composite material of the present invention has the advantages of good mechanical properties, good processing fluidity, environmental protection and biodegradability, and wide availability of raw materials. It is suitable as a 3D printing material for printing various prostheses and medical device molds. Moreover, its preparation method is simple and the production cost is low, making it suitable for large-scale industrial production and application.

[0028] Specifically:

[0029] 1) The base material of the polylactic acid composite material of the present invention is polylactic acid, which is a biodegradable material. Both ramie fiber and nanocellulose can be biodegraded, thus giving the polylactic acid composite material the characteristics of being environmentally friendly and biodegradable.

[0030] 2) The polylactic acid composite material of the present invention contains ramie fiber, which can effectively improve the mechanical strength of the polylactic acid composite material, and the product obtained by 3D printing is not easily deformed and can withstand greater loads.

[0031] 3) The polylactic acid composite material of the present invention contains nanocellulose, which has a high aspect ratio and can fill the gap between polylactic acid and ramie fibers. During the 3D printing process, it can increase the viscosity of the polymer melt, which is beneficial to improving the adhesion between layers.

[0032] 4) The polylactic acid composite material of the present invention contains a silane coupling agent and a plasticizer. The silane coupling agent undergoes hydrolysis and polymerization, and can form covalent bonds and hydrogen bonds with the hydroxyl groups on the surface of nanocellulose. Combined with the plasticizer, it can significantly improve the compatibility of nanocellulose with polylactic acid and ramie fiber.

[0033] 5) The preparation method of the polylactic acid composite material of the present invention is simple and has low production cost, making it suitable for large-scale industrial production and application. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the preparation process of the polylactic acid composite material of the present invention. Detailed Implementation

[0035] The present invention will be further explained and described below with reference to specific embodiments.

[0036] Example 1:

[0037] A polylactic acid composite material, the composition of which is shown in the table below:

[0038] Table 1. Composition of a polylactic acid composite material

[0039]

[0040] Note:

[0041] The preparation method of ramie fiber is as follows: ramie leaves are cut into pieces and then soaked in an aqueous solution of H2O2-CH2O2-H2SO4 at 60℃ for 1 hour. The molar ratio of H2O2, CH2O2, and H2SO4 in the aqueous solution is 1:1:0.2, and the mass ratio of ramie leaves to the aqueous solution is 1:10. The mixture is then ground, filtered, and the solid is placed in an oven and dried at 65℃ for 1 hour to obtain ramie fiber.

[0042] The preparation method of the above polylactic acid composite material is as follows (preparation flow chart is shown below). Figure 1 As shown):

[0043] TEMPO CNF and water were added to a high-pressure homogenizer for high-pressure homogenization to prepare a nanocellulose dispersion. The mass ratio of TEMPO CNF to water was 1:10. Then, silane coupling agent KH-550 was added and mechanically stirred for 1 hour. Then, plasticizer PEG-400 was added and mechanically stirred for 1 hour. Then, polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours. Then, the mixture was placed in an oven and dried at 60°C for 15 hours. Then, it was injected into a single-screw extruder and melt-mixed at 170°C and 220 rpm. Finally, it was extruded to obtain polylactic acid composite material (filaments with a diameter of 1.75 mm).

[0044] Example 2:

[0045] A polylactic acid composite material, the composition of which is shown in the table below:

[0046] Table 2. Composition of a polylactic acid composite material

[0047]

[0048]

[0049] The preparation method of the above polylactic acid composite material is as follows (preparation flow chart is shown below). Figure 1 As shown):

[0050] TEMPO CNF and water were added to a high-pressure homogenizer for high-pressure homogenization to prepare a nanocellulose dispersion. The mass ratio of TEMPO CNF to water was 1:10. Then, silane coupling agent KH-550 was added and mechanically stirred for 1 hour. Then, plasticizer PEG-400 was added and mechanically stirred for 1 hour. Then, polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours. Then, the mixture was placed in an oven and dried at 60°C for 15 hours. Then, it was injected into a single-screw extruder and melt-mixed at 170°C and 220 rpm. Finally, it was extruded to obtain polylactic acid composite material (filaments with a diameter of 1.75 mm).

[0051] Example 3:

[0052] A polylactic acid composite material, the composition of which is shown in the table below:

[0053] Table 3. Composition of a polylactic acid composite material

[0054]

[0055] The preparation method of the above polylactic acid composite material is as follows (preparation flow chart is shown below). Figure 1 As shown):

[0056] TEMPO CNF and water were added to a high-pressure homogenizer for high-pressure homogenization to prepare a nanocellulose dispersion. The mass ratio of TEMPO CNF to water was 1:10. Then, silane coupling agent KH-550 was added and mechanically stirred for 1 hour. Then, plasticizer PEG-400 was added and mechanically stirred for 1 hour. Then, polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours. Then, the mixture was placed in an oven and dried at 60°C for 15 hours. Then, it was injected into a single-screw extruder and melt-mixed at 170°C and 220 rpm. Finally, it was extruded to obtain polylactic acid composite material (filaments with a diameter of 1.75 mm).

[0057] Example 4:

[0058] A polylactic acid composite material, the composition of which is shown in the table below:

[0059] Table 4. Composition of a polylactic acid composite material

[0060]

[0061] The preparation method of the above polylactic acid composite material is as follows (preparation flow chart is shown below). Figure 1 As shown):

[0062] TEMPO CNF and water were added to a high-pressure homogenizer for high-pressure homogenization to prepare a nanocellulose dispersion. The mass ratio of TEMPO CNF to water was 1:10. Then, silane coupling agent KH-550 was added and mechanically stirred for 1 hour. Then, plasticizer PEG-400 was added and mechanically stirred for 1 hour. Then, polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours. Then, the mixture was placed in an oven and dried at 60°C for 15 hours. Then, it was injected into a single-screw extruder and melt-mixed at 170°C and 220 rpm. Finally, it was extruded to obtain polylactic acid composite material (filaments with a diameter of 1.75 mm).

[0063] Comparative Example 1:

[0064] A polylactic acid material, prepared by the following method:

[0065] Polylactic acid (number average molecular weight of 70,000 g / mol) is injected into a single-screw extruder and melt-mixed at 170°C and 220 rpm. Then it is extruded to obtain polylactic acid material (filaments with a diameter of 1.75 mm).

[0066] Comparative Example 2:

[0067] A polylactic acid composite material, the composition of which is shown in the table below:

[0068] Table 5. Composition of a polylactic acid composite material

[0069]

[0070] The preparation method of the above polylactic acid composite material is as follows:

[0071] TEMPO CNF and water were added to a high-pressure homogenizer for high-pressure homogenization to prepare a nanocellulose dispersion. The mass ratio of TEMPO CNF to water was 1:10. Then, silane coupling agent KH-550 was added and mechanically stirred for 1 hour. Then, plasticizer PEG-400 was added and mechanically stirred for 1 hour. Then, polylactic acid was added and mechanically stirred for 0.5 hours. The mixture was then placed in an oven and dried at 60°C for 15 hours. The mixture was then injected into a single-screw extruder and melt-mixed at 170°C and 220 rpm. Finally, it was extruded to obtain a polylactic acid composite material (filaments with a diameter of 1.75 mm).

[0072] Comparative Example 3:

[0073] A polylactic acid composite material, the composition of which is shown in the table below:

[0074] Table 6. Composition of a polylactic acid composite material

[0075] Components Quality Polylactic acid (number average molecular weight 70,000 g / mol) 85 Ramie fiber (same as in Example 1) 10 Silane coupling agent KH-550 5 Plasticizer PEG-400 2

[0076] The preparation method of the above polylactic acid composite material is as follows:

[0077] Polylactic acid, ramie fiber, silane coupling agent KH-550 and plasticizer PEG-400 are injected into a single screw extruder and melt-blended at 170°C and 220 rpm, and then extruded to obtain polylactic acid composite material (filaments with a diameter of 1.75 mm).

[0078] Performance testing:

[0079] The mechanical property test data of the polylactic acid materials of Examples 1-4 and Comparative Examples 1-3 are shown in the table below:

[0080] Table 7 Mechanical property test data of polylactic acid materials

[0081]

[0082] Note:

[0083] Mechanical properties: Tested in accordance with "ASTM D3039 / D3039M-07 Standard Test Method for Tensile Properties of Polymer-Based Composites" and "ASTM D790 Bending Test for Thermoplastic Resin-Based Composites".

[0084] As shown in Table 7:

[0085] 1) The higher the polylactic acid (matrix) content in the polylactic acid materials of Examples 1-4, the higher the mechanical strength;

[0086] 2) Compared with the polylactic acid materials of Comparative Examples 1 to 3, the polylactic acid materials of Examples 1 to 4 have significantly improved compressive strength, indicating that ramie fibers and nanocellulose form strong chemical forces (physical entanglement) at the nanoscale, thereby forming a dense structure, which ultimately significantly improves the impact resistance and toughness of polylactic acid materials.

[0087] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A polylactic acid composite material, characterized in that, The components include the following parts by weight: Polylactic acid: 60-80 parts; Ramie fiber: 10 to 30 parts; Nanocellulose: 5 to 15 parts; Silane coupling agent: 3 to 7 parts; Plasticizer: 1 to 3 parts; The nanocellulose is TEMPO CNF.

2. The polylactic acid composite material according to claim 1, characterized in that: The polylactic acid has a number-average molecular weight of 70,000 g / mol to 75,000 g / mol.

3. The polylactic acid composite material according to claim 1, characterized in that: The ramie fibers have a length of 45μm to 60μm and a diameter of 10μm to 40μm.

4. The polylactic acid composite material according to any one of claims 1 to 3, characterized in that: The nanocellulose has a length of 1 nm to 100 nm and a diameter of 3 nm to 10 nm.

5. The polylactic acid composite material according to any one of claims 1 to 3, characterized in that: The silane coupling agent is silane coupling agent KH-550.

6. The polylactic acid composite material according to any one of claims 1 to 3, characterized in that: The plasticizer is polyethylene glycol.

7. A method for preparing a polylactic acid composite material according to any one of claims 1 to 6, characterized in that, The process includes the following steps: dispersing nanocellulose with water to prepare a nanocellulose dispersion, adding a silane coupling agent to modify the surface of the nanocellulose, adding a plasticizer and mixing well, adding polylactic acid and ramie fiber and mixing well, drying, and then extruding to obtain a polylactic acid composite material.

8. A 3D printing material, characterized in that, The polylactic acid composite material comprising any one of claims 1 to 6.

9. An application of the polylactic acid composite material as described in any one of claims 1 to 6 for the preparation of prostheses or medical device molds.

Images