Fully-degradable bamboo-based composite material for 3D printing and preparation method of fully-degradable bamboo-based composite material

Abstract

The invention relates to the technical field of 3D printing materials, and discloses a full-degradable bamboo-based composite material for 3D printing and a preparation method of the full-degradable bamboo-based composite material for 3D printing. 30%-50% of a bio-based thermoplastic material; the bio-based thermoplastic material is selected from at least one of polyhydroxyalkanoate (PHA), poly (butylene succinate) (PBS) or thermoplastic starch (TPS); 5%-10% of an interface modifier; the interface modifier is a compound of chitosan and citric acid, and the mass ratio of the chitosan to the citric acid is (1: 1)-(2: 1); 0.5%-2% of a functional auxiliary agent; the functional auxiliary agent comprises but is not limited to a natural antioxidant, a bio-based plasticizer and a halogen-free flame retardant. The bamboo fiber powder and the full-degradable bio-based material (PHA / PBS / TPS) are compounded according to a specific proportion, and the chitosan-citric acid composite interface modifier is combined, so that the interface bonding force is remarkably improved. Natural functional auxiliaries are added, and the requirements for oxidation resistance, plasticizing flowability and flame retardance are synchronously met.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing materials, and specifically relates to a fully degradable bamboo-based composite material for 3D printing and a preparation method thereof. Background Art

[0002] Existing 3D printing consumables mostly rely on petroleum-based plastics (such as ABS, PLA), which have problems such as non-degradability and environmental pollution. Although some bio-based materials (such as PLA) have been applied, their degradation depends on industrial composting conditions, and their mechanical properties and printing stability are insufficient. Although bamboo fibers have natural degradability, their poor interfacial compatibility with bio-based resins limits their application in 3D printing.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] In order to solve the problems of poor interfacial compatibility between bamboo fibers and bio-based resins, insufficient mechanical properties of printing consumables, and limited degradation conditions, the basic concept of the technical solution adopted in the present invention is as follows:

[0005] A fully degradable bamboo-based composite material for 3D printing is composed of the following components in mass percentage:

[0006] Bamboo fiber powder: 40%-60%; the particle size of the bamboo fiber powder is 50-200 mesh, the aspect ratio of the bamboo fiber powder is ≥5, the cellulose content of the bamboo fiber powder is ≥70%, and the lignin content of the bamboo fiber powder is ≤15%;

[0007] Bio-based thermoplastic material: 30%-50%; the bio-based thermoplastic material is selected from at least one of polyhydroxyalkanoate PHA, polybutylene succinate PBS, or thermoplastic starch TPS;

[0008] Interface modifier: 5%-10%; the interface modifier is a complex of chitosan and citric acid, and the mass ratio of chitosan to citric acid is 1:1-2:1;

[0009] Functional additive: 0.5%-2%; the functional additive includes but is not limited to natural antioxidants, bio-based plasticizers, and halogen-free flame retardants.

[0010] As a preferred embodiment of the present invention, the bamboo fiber powder is the fiber obtained by steam explosion treatment of bamboo, and the surface area of the bamboo fiber powder is 2-5 m 2 / g.

[0011] As a preferred embodiment of the present invention, the bio-based thermoplastic material is a blend of PHA and PBS, and the blending mass ratio is 6:4.

[0012] As a preferred embodiment of the present invention, the compounding ratio of the interface modifier is chitosan:citric acid = 1.5:1.

[0013] As a preferred embodiment of the present invention, the natural antioxidant is rosemary extract, the bio-based plasticizer is glycerol, and the halogen-free flame retardant is ammonium phytate.

[0014] A preparation method of a fully degradable bamboo-based composite material for 3D printing, comprising the following working steps:

[0015] The first step: drying the bamboo fiber powder at 80-100 °C for 4-6 hours;

[0016] The second step: mixing the dried bamboo fiber powder with the interface modifier in a high-speed mixer at 50-70 °C for 10-15 minutes;

[0017] The third step: adding the bio-based thermoplastic material and the functional additives, and melt-blending in a twin-screw extruder, the extrusion temperature is 140-170 °C, and the screw speed is 200-300 rpm;

[0018] The fourth step: cooling and pelletizing the extrudate to obtain 3D printing consumable particles.

[0019] The present invention has the following beneficial effects compared with the prior art:

[0020] 1. The present invention combines bamboo fiber powder with a fully degradable bio-based material (PHA / PBS / TPS) in a specific ratio, and combines a chitosan-citric acid composite interface modifier to significantly improve the interfacial bonding strength.

[0021] 2. The present invention adds natural functional additives (rosemary extract, glycerol, ammonium phytate) to simultaneously solve the requirements of antioxidant, plasticizing fluidity and flame retardancy.

[0022] 3. The present invention uses steam explosion pretreatment of bamboo fibers to reduce the lignin content and improve the fiber dispersibility; the present invention adopts a segmented mixing process (first fiber modification and then resin blending) to avoid damaging the fiber structure at high temperature.

[0023] 4. The tensile strength of the printed products of the present invention is ≥40 MPa (40% higher than that of pure PLA); the natural degradation period is ≤1 year (the mass loss rate is ≥90% after 180 days of soil burial); and the materials of the present invention are 100% bio-based sources, without petroleum-based components and microplastic residues, and are more environmentally friendly. Specific embodiments

[0024] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments are clearly and completely described below. The following embodiments are used to illustrate the present invention.

[0025] A fully biodegradable bamboo-based composite material for 3D printing, which is composed of components with the following mass percentages:

[0026] Bamboo fiber powder: 40%-60%; the particle size of the bamboo fiber powder is 50-200 mesh, the aspect ratio of the bamboo fiber powder is ≥5, the cellulose content of the bamboo fiber powder is ≥70%, and the lignin content of the bamboo fiber powder is ≤15%;

[0027] Bio-based thermoplastic material: 30%-50%; the bio-based thermoplastic material is selected from at least one of polyhydroxyalkanoate PHA, polybutylene succinate PBS or thermoplastic starch TPS;

[0028] Interface modifier: 5%-10%; the interface modifier is a composite of chitosan and citric acid, and the mass ratio of chitosan to citric acid is 1:1-2:1;

[0029] Functional additive: 0.5%-2%; the functional additive includes but is not limited to natural antioxidants, bio-based plasticizers and halogen-free flame retardants.

[0030] Specifically, the bamboo fiber powder is the fiber after the bamboo is treated by steam explosion, and the surface area of the bamboo fiber powder is 2-5m 2 / g.

[0031] Specifically, the bio-based thermoplastic material is a blend of PHA and PBS, and the blending mass ratio is 6:4.

[0032] Specifically, the compounding ratio of the interface modifier is chitosan:citric acid = 1.5:1.

[0033] Specifically, the natural antioxidant is rosemary extract, the bio-based plasticizer is glycerol, and the halogen-free flame retardant is ammonium phytate.

[0034] A preparation method of a fully biodegradable bamboo-based composite material for 3D printing, which includes the following working steps:

[0035] The first step: drying the bamboo fiber powder at 80-100°C for 4-6 hours;

[0036] The second step: mixing the dried bamboo fiber powder with the interface modifier in a high-speed mixer at 50-70°C for 10-15 minutes;

[0037] The third step: adding the bio-based thermoplastic material and the functional additive, and performing melt blending in a twin-screw extruder, the extrusion temperature is 140-170°C, and the screw speed is 200-300 rpm;

[0038] The fourth step: cooling and pelletizing the extrudate to obtain 3D printing consumable particles.

[0039] Example 1

[0040] A fully biodegradable bamboo-based composite material for 3D printing, which is composed of the following components in mass percentage:

[0041] Bamboo fiber powder: 55% (steam explosion treatment, particle size 100 mesh, cellulose content 72%);

[0042] PHA / PBS blend: 40% (mass ratio 6:4);

[0043] Interface modifier: 8% (chitosan:citric acid = 1.5:1);

[0044] Rosemary extract: 0.3%, glycerol: 1%, ammonium phytate: 0.7%.

[0045] Specific preparation method of Example 1:

[0046] First step: The bamboo fiber powder is dried at 90°C for 5 hours;

[0047] Second step: Mix with the interface modifier at 60°C for 12 minutes;

[0048] Third step: Add the PHA / PBS blend and additives, and co-extrude at 160°C and 250 rpm in a twin-screw extruder;

[0049] Fourth step: Water-cooling pelletizing to obtain 1.75 mm diameter wire rods.

[0050] Fifth step: Performance testing:

[0051] Melt index (190°C / 2.16 kg): 7 g / 10 min (meeting the FDM fluidity requirements);

[0052] Interlayer bonding strength: 10 MPa (comparative example: the unmodified group is only 4 MPa);

[0053] Mass loss rate after 180 days of soil burial: 92%.

[0054] The present invention combines bamboo fiber powder in a specific proportion with a fully biodegradable bio-based material (PHA / PBS / TPS), and combines with a chitosan-citric acid composite interface modifier to significantly improve the interfacial bonding force.

[0055] The present invention adds natural functional additives (rosemary extract, glycerol, ammonium phytate) to simultaneously solve the requirements of antioxidant, plasticizing fluidity and flame retardancy.

[0056] The present invention uses steam explosion pretreatment of bamboo fibers to reduce the lignin content and improve the fiber dispersion; the present invention adopts a segmented mixing process (first fiber modification and then resin blending) to avoid damaging the fiber structure at high temperature.

[0057] The tensile strength of the printed product of the present invention is ≥40 MPa (40% higher than that of pure PLA); the natural degradation period is ≤1 year (the mass loss rate is ≥90% after 180 days of soil burial); and the material of the present invention is 100% bio-based, without petroleum-based components and microplastic residues, which is more environmentally friendly.

[0058] It can be understood that the present invention is described by means of some embodiments. Those skilled in the art know that, without departing from the spirit and scope of the present invention, various changes or equivalent substitutions can be made to these features and embodiments. Additionally, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A fully degradable bamboo-based composite material for 3D printing, characterized in that, Composed of components with the following mass percentages: Bamboo fiber powder: 40% - 60%; the particle size of the bamboo fiber powder is 50 - 200 mesh, the aspect ratio of the bamboo fiber powder is ≥5, the cellulose content of the bamboo fiber powder is ≥70%, and the lignin content of the bamboo fiber powder is ≤15%; Bio-based thermoplastic material: 30% - 50%; the bio-based thermoplastic material is selected from at least one of polyhydroxyalkanoate PHA, polybutylene succinate PBS, or thermoplastic starch TPS; Interface modifier: 5% - 10%; the interface modifier is a complex of chitosan and citric acid, and the mass ratio of chitosan to citric acid is 1:1 - 2:1; Functional additive: 0.5% - 2%; the functional additive includes but is not limited to natural antioxidants, bio-based plasticizers, and halogen-free flame retardants.

2. The fully degradable bamboo-based composite material for 3D printing according to claim 1, wherein The bamboo fiber powder is the fiber obtained by subjecting bamboo to steam explosion treatment, and the surface area of the bamboo fiber powder is 2-5 m 2 / g.

3. The fully biodegradable bamboo-based composite material for 3D printing according to claim 1, characterized in that The bio-based thermoplastic material is a blend of PHA and PBS, and the blending mass ratio is 6:

4.

4. The fully biodegradable bamboo-based composite material for 3D printing according to claim 1, characterized in that, The composite ratio of the interface modifier is chitosan:citric acid = 1.5:

1.

5. The fully biodegradable bamboo-based composite material for 3D printing according to claim 1, characterized in that, The natural antioxidant is rosemary extract, the bio-based plasticizer is glycerol, and the halogen-free flame retardant is ammonium phytate.

6. A preparation method of a fully degradable bamboo-based composite material for 3D printing, characterized in that, Including the following working steps: First step: Dry the bamboo fiber powder at 80 - 100 °C for 4 - 6 hours; Second step: Mix the dried bamboo fiber powder with the interface modifier in a high-speed mixer at 50 - 70 °C for 10 - 15 minutes; Third step: Add the bio-based thermoplastic material and the functional additive, and melt-blend in a twin-screw extruder. The extrusion temperature is 140 - 170 °C, and the screw speed is 200 - 300 rpm; Fourth step: Cool and pelletize the extrudate to obtain 3D printing consumable particles.