Polylactic acid composite material as well as preparation method and application thereof

Abstract

The invention discloses a polylactic acid composite material as well as a preparation method and application thereof. The polylactic acid composite material is prepared from polylactic acid, ramie fibers, nano cellulose, a silane coupling agent and a plasticizer. The preparation method of the polylactic acid composite material comprises the following steps: adding water into nano-crystalline cellulose, dispersing to prepare nano-crystalline cellulose dispersion liquid, adding a silane coupling agent, carrying out surface modification on the nano-crystalline cellulose, adding a plasticizer, uniformly mixing, adding polylactic acid and ramie fibers, uniformly mixing, drying, and carrying out extrusion molding to obtain the polylactic acid composite material. The polylactic acid composite material is obtained. The polylactic acid composite material disclosed by the invention has the advantages of good mechanical property, good processing fluidity, environmental protection, degradability, wide raw material source and the like, is suitable for being used as a 3D printing material for printing various prostheses and medical instrument molds, and is simple in preparation method, low in production cost and suitable for large-scale industrial production and application.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a polylactic acid composite material and a preparation method and application thereof. Background Art

[0002] 3D printing (3DP), also known as Additive Manufacturing Technologies (AM), is a technology that manufactures physical parts by accumulating materials layer by layer based on three-dimensional CAD data. In recent years, 3D printing technology has been widely used in the medical field, such as 3D printing of various prostheses, 3D printing of various medical device molds, etc. As we all know, 3D printing materials are one of the keys to 3D printing technology, and they play a decisive role in the performance of printed products. At present, the base materials of 3D printing materials commonly used in the medical field are mainly petroleum-based materials, which will inevitably produce a large amount of medical waste that is difficult to degrade and recycle, which will bring serious environmental pollution problems and it is difficult to fully meet the requirements of actual applications.

[0003] Therefore, it is of great significance to develop a 3D printing material with good mechanical properties, good processing fluidity, and environmental protection and biodegradability. Summary of the invention

[0004] The purpose of the present invention is to provide a polylactic acid composite material and a preparation method and application thereof.

[0005] The technical solution adopted by the present invention is:

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

[0007] Polylactic acid: 60 to 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 number average molecular weight of the polylactic acid is 70000 g / mol to 75000 g / mol.

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

[0014] Preferably, the ramie fiber is prepared by a preparation method comprising the following steps: cutting ramie leaves into pieces, and then soaking them in H 2 O2 -CH 2 O 2 -H 2 SO 4 The ramie fiber is soaked in an aqueous solution, ground, filtered, and the solid is dried to obtain ramie fiber.

[0015] Preferably, the H 2 O 2 -CH 2 O 2 -H 2 SO 4 H in aqueous solution 2 O 2 , CH 2 O 2 , H 2 SO 4 The molar ratio is 1:0.9~1.1:0.15~0.25.

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

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

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

[0019] Preferably, the nanocellulose has a length of 1 nm to 100 nm and a diameter of 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 filament form with a diameter of 1.75 mm to 1.95 mm.

[0023] A preparation method of the polylactic acid composite material as described above comprises the following steps: dispersing nanocellulose in 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 a polylactic acid composite material.

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

[0025] A 3D printing material, comprising the polylactic acid composite material.

[0026] An application of the polylactic acid composite material as described above for preparing a prosthesis or a medical device mold.

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

[0028] Specifically:

[0029] 1) The substrate in the polylactic acid composite material of the present invention is polylactic acid, which is a biodegradable material, and both ramie fiber and nanocellulose are biodegradable, thereby giving the polylactic acid composite material environmentally friendly and degradable characteristics;

[0030] 2) Ramie fiber is added to the polylactic acid composite material of the present invention, which can effectively improve the mechanical strength of the polylactic acid composite material, and the product obtained by 3D printing is not easy to deform and can withstand a larger load;

[0031] 3) Nanocellulose is added to the polylactic acid composite material of the present invention, which has a high aspect ratio and can fill the gap between polylactic acid and ramie fiber. It can increase the viscosity of the polymer melt during the 3D printing process, which is beneficial to improve 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 the nanocellulose. Combined with the plasticizer, the compatibility of the nanocellulose with the polylactic acid and the ramie fiber can be significantly improved.

[0033] 5) The preparation method of the polylactic acid composite material of the present invention is simple and has low production cost, and is suitable for large-scale industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of the preparation of the polylactic acid composite material. DETAILED DESCRIPTION

[0035] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0036] Embodiment 1:

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

[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 immersed in H 2 O 2 -CH 2 O 2 -H 2 SO 4 Soak in water solution at 60℃ for 1h, H 2 O 2 -CH 2 O 2 -H 2 SO 4 H in aqueous solution 2 O 2 , CH 2 O 2 , H 2 SO 4 The molar ratio of ramie leaves and H 2 O 2 -CH 2 O 2 -H 2 SO 4 The mass ratio of the aqueous solution is 1:10, and then it is ground and filtered. The solid is placed in an oven at 65°C and dried for 1 hour to obtain ramie fiber.

[0042] The preparation method of the above-mentioned polylactic acid composite material is as follows (the preparation flow chart is as follows Figure 1 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, and then the silane coupling agent KH-550 was added and mechanically stirred for 1 hour, and then the plasticizer PEG-400 was added and mechanically stirred for 1 hour, and then polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours, and then placed in an oven at 60°C for 15 hours, and then injected into a single-screw extruder, melt-mixed at 170°C and a rotation speed of 220rpm, and then extruded to obtain a polylactic acid composite material (filamentous, with a diameter of 1.75mm).

[0044] Embodiment 2:

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

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

[0047]

[0048]

[0049] The preparation method of the above-mentioned polylactic acid composite material is as follows (the preparation flow chart is as follows Figure 1 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, and then the silane coupling agent KH-550 was added and mechanically stirred for 1 hour, and then the plasticizer PEG-400 was added and mechanically stirred for 1 hour, and then polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours, and then placed in an oven at 60°C for 15 hours, and then injected into a single-screw extruder, melt-mixed at 170°C and a rotation speed of 220rpm, and then extruded to obtain a polylactic acid composite material (filamentous, with a diameter of 1.75mm).

[0051] Embodiment 3:

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

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

[0054]

[0055] The preparation method of the above-mentioned polylactic acid composite material is as follows (the preparation flow chart is as follows Figure 1 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, and then the silane coupling agent KH-550 was added and mechanically stirred for 1 hour, and then the plasticizer PEG-400 was added and mechanically stirred for 1 hour, and then polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours, and then placed in an oven at 60°C for 15 hours, and then injected into a single-screw extruder, melt-mixed at 170°C and a rotation speed of 220rpm, and then extruded to obtain a polylactic acid composite material (filamentous, with a diameter of 1.75mm).

[0057] Embodiment 4:

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

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

[0060]

[0061] The preparation method of the above-mentioned polylactic acid composite material is as follows (the preparation flow chart is as follows Figure 1 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, and then the silane coupling agent KH-550 was added and mechanically stirred for 1 hour, and then the plasticizer PEG-400 was added and mechanically stirred for 1 hour, and then polylactic acid and ramie fiber were added and mechanically stirred for 0.5 hours, and then placed in an oven at 60°C for 15 hours, and then injected into a single-screw extruder, melt-mixed at 170°C and a rotation speed of 220rpm, and then extruded to obtain a polylactic acid composite material (filamentous, with a diameter of 1.75mm).

[0063] Comparative Example 1:

[0064] A polylactic acid material, the preparation method is as follows:

[0065] Polylactic acid (number average molecular weight of 70,000 g / mol) was injected into a single screw extruder, melt-kneaded at 170° C. and a rotation speed of 220 rpm, and then extruded to obtain a polylactic acid material (filamentous, 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 following table:

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

[0069]

[0070] The preparation method of the above-mentioned 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 TEMPOCNF to water was 1:10, and then the silane coupling agent KH-550 was added and mechanically stirred for 1 hour, and then the plasticizer PEG-400 was added and mechanically stirred for 1 hour, and then polylactic acid was added and mechanically stirred for 0.5 hours, and then placed in an oven at 60°C for 15 hours, and then injected into a single-screw extruder, melt-kneaded at 170°C and a rotation speed of 220rpm, and then extruded to obtain a polylactic acid composite material (filamentous, with a diameter of 1.75mm).

[0072] Comparative Example 3:

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

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

[0075] Components Mass Polylactic acid (number average molecular weight 70000g / mol) 85 Ramie fiber (same as Example 1) 10 Silane coupling agent KH-550 5 Plasticizer PEG-400 2

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

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

[0078] Performance Test:

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

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

[0081]

[0082] Note:

[0083] Mechanical properties: Tested with reference to "ASTM D3039 / D3039M-07 Standard Test Method for Tensile Properties of Polymer Matrix Composites" and "ASTM D790 Flexural Test for Thermoplastic Resin Matrix Composites".

[0084] From Table 7, we can see that:

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

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

[0087] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A polylactic acid composite material, characterized in that: The composition comprises the following components in parts by weight: Polylactic acid: 60 to 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.

2. The polylactic acid composite material according to claim 1, characterized in that: The number average molecular weight of the polylactic acid is 70000 g / mol to 75000 g / mol.

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

4. The polylactic acid composite material according to claim 1, characterized in that: The nanocellulose is TEMPO CNF.

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

6. The polylactic acid composite material according to any one of claims 1 to 4, characterized in that: The silane coupling agent is silane coupling agent KH-550.

7. The polylactic acid composite material according to any one of claims 1 to 4, characterized in that: The plasticizer is polyethylene glycol.

8. A method for preparing a polylactic acid composite material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: dispersing the 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 evenly, adding polylactic acid and ramie fiber and mixing evenly, drying, and extruding to obtain a polylactic acid composite material.

9. A 3D printing material, characterized in that: A polylactic acid composite material comprising any one of claims 1 to 7.

10. Use of the polylactic acid composite material according to any one of claims 1 to 7 for preparing a prosthesis or a medical device mold.

Images