A polylactic acid composite material based on 3D printing and preparation method thereof

Abstract

The invention relates to the field of polylactic acid materials, and specifically discloses a polylactic acid composite material based on 3D printing and a preparation method thereof; the preparation of the polylactic acid composite material comprises the following steps: S1: taking mica powder, water, ethanol, aminosilane coupling agent, vinylsilane coupling agent, stirring, filtering, and drying to obtain modified mica powder; taking modified mica powder, water, acetic acid, glutaraldehyde, and D-sorbitol, stirring at 40-60 DEG C for 2-3 hours, adding polymethyl methacrylate and an initiator, heating at 65-75 DEG C for 2-3 hours, filtering and drying to obtain a modified filler; S2: taking poly (L)-lactic acid and poly (D)-lactic acid in a mass ratio of 1:(0.8-1.2) to obtain a polylactic acid composition; S3: taking the polylactic acid composition, polybutylene adipate, the modified filler, and an antioxidant, mixing them uniformly, and melt-blending, extruding, and granulating at 240-250 DEG C to obtain a polylactic acid composite material.

Description

Technical Field

[0001] The present invention relates to the field of polylactic acid materials, and specifically discloses a polylactic acid composite material based on 3D printing and a preparation method thereof. Background Art

[0002] With the implementation of the plastic ban, the research on biodegradable plastics has become a hot topic. Polylactic acid has good biocompatibility and processing performance, and can replace petroleum-based polymers to a certain extent. It is widely used in biomedicine, automotive industry, packaging materials, textile industry and other fields, and is also an ideal 3D printing material.

[0003] However, polylactic acid has a slow crystallization rate and low crystallinity, which leads to poor toughness and heat resistance, seriously limiting its application. In order to improve the poor toughness and heat resistance of polylactic acid, it is of great significance to study a polylactic acid composite material based on 3D printing and its preparation method. Summary of the invention

[0004] The object of the present invention is to provide a polylactic acid composite material based on 3D printing and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for preparing a polylactic acid composite material based on 3D printing: comprising the following steps: S1: taking mica powder, water, ethanol, aminosilane coupling agent, vinyl silane coupling agent, stirring, filtering, and drying to obtain modified mica powder; taking modified mica powder, water, acetic acid, glutaraldehyde, and D-sorbitol, stirring at 40-60°C for 2-3h, adding polymethyl methacrylate and initiator azobisisobutyronitrile, heating at 65-75°C for 2-3h, filtering and drying to obtain a modified filler;

[0006] S2: taking a polylactic acid composition, polybutylene adipate, a modified filler and an antioxidant, mixing them evenly, and melt-blending and extruding them at 240-250° C. to obtain a polylactic acid composite material.

[0007] More optimally, the modified mica powder includes the following raw materials, calculated by mass: 10 parts of mica powder, 50-60 parts of water, 50-60 parts of ethanol, 0.2-0.5 parts of aminosilane coupling agent, and 1-2 parts of vinyl silane coupling agent; the modified filler includes the following raw materials, calculated by mass: 10 parts of modified mica powder, 50-60 parts of water, 50-60 parts of acetic acid, 1-2 parts of glutaraldehyde, 0.5-0.8 parts of D-sorbitol, 15-20 parts of polymethyl methacrylate, and 0.01-0.02 parts of initiator.

[0008] More optimally, the polylactic acid composite material includes the following raw materials, calculated by weight: 100 parts of polylactic acid composition, 30-35 parts of polybutylene adipate, 20-25 parts of modified filler, and 0.1-0.2 parts of antioxidant.

[0009] More optimally, the preparation of the polylactic acid composition includes the following steps: taking poly (L)-lactic acid and poly (D)-lactic acid, dissolving them in chloroform respectively to obtain solution A and solution B; adding methanol respectively, reversing precipitation and purification, separating and filtering the precipitation, volatilizing, and drying to obtain substance A and substance B respectively; mixing to obtain a mixture, adding chloroform and stirring for 3-4 hours, volatilizing, and drying to obtain a polylactic acid composition.

[0010] More optimally, the mass ratio of the poly (L)-lactic acid to the poly (D)-lactic acid is 1:(0.8-1.2).

[0011] More optimally, the preparation of the polylactic acid composition includes the following steps: taking poly (L)-lactic acid and poly (D)-lactic acid, dissolving them in chloroform (1 g / mL) respectively to obtain solution A and solution B; adding methanol 8 to 10 times the mass of solution A and solution B respectively, reversing precipitation and purification, separating and filtering the precipitation, volatilizing, and drying to obtain substance A and substance B respectively; mixing to obtain a mixture, adding chloroform (1 g / mL), stirring for 3 to 4 hours, volatilizing, and drying to obtain a polylactic acid composition.

[0012] More optimally, the preparation of the poly L-lactic acid and poly D-lactic acid comprises the following steps: taking lactic acid, pre-treating it, adding anacardic acid, polyethylene glycol, stannous isooctanoate, and p-toluenesulfonic acid monohydrate, heating it at 110-115°C under reduced pressure for 0.5-1h, heating it to 130-135°C, heating it for 0.5-1h, heating it to 160-165°C, adding 1-2 parts of malic acid, polycondensing it under reduced pressure for 24-25h, adding dichloromethane and stirring it evenly, adding methanol solution and stirring it evenly, centrifuging and precipitating it, and drying it to obtain polylactic acid;

[0013] When the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid.

[0014] More optimally, the polylactic acid comprises the following raw materials, calculated by mass: 20-25 parts of lactic acid, 10-15 parts of anacardic acid, 5-8 parts of polyethylene glycol, 0.1-0.3 parts of stannous isooctanoate, 0.03-0.05 parts of p-toluenesulfonic acid monohydrate, and 1-2 parts of malic acid.

[0015] More optimally, the polyethylene glycol is carboxyl-polyethylene glycol-hydroxyl.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: a certain mass ratio of poly-L-lactic acid and poly-D-lactic acid is added to the polylactic acid composition, and the stereocomplexed polylactic acid is obtained by mixing, and the intermolecular interaction is stronger, which can significantly improve the problem of poor heat resistance of polylactic acid; however, stereocomplexation will lead to enhanced brittleness of polylactic acid, therefore, anacardic acid, polyethylene glycol and malic acid are added when preparing poly-L-lactic acid and poly-D-lactic acid; anacardic acid has a long-chain alkyl and benzene ring structure, which can improve the toughness and heat resistance of polylactic acid; Polyethylene glycol uses carboxyl-polyethylene glycol-hydroxyl, which is introduced into the polylactic acid segment through copolymerization reaction, which has a good toughening effect; the introduction of malic acid increases the branching structure, which helps to improve toughness; the above three raw materials are copolymerized with lactic acid to obtain polylactic acid, which has good heat resistance and toughness; when the lactic acid is L-lactic acid, the polylactic acid obtained is poly-L-lactic acid, and when the lactic acid is D-lactic acid, the polylactic acid obtained is poly-D-lactic acid, so poly-L-lactic acid and poly-D-lactic acid also have good compatibility, which is conducive to blending;

[0017] In order to further improve the toughness of the polylactic acid composition, more polybutylene adipate is added; in order to avoid the performance degradation problem caused by poor compatibility between the two, a modified filler is added; the mica powder in the modified filler increases the mechanical properties of the polylactic acid composition on the one hand, and acts as a nucleating agent to improve the heat resistance on the other hand; the modified filler also includes D-sorbitol and polymethyl methacrylate, among which D-sorbitol provides more nucleating sites, and polymethyl methacrylate acts as a physical compatibilizer to improve the problem of weak interface bonding between the polylactic acid composition and polybutylene adipate; the modified filler obtained by compounding the above raw materials has good compatibility in the polylactic acid composition, and has a large molecular weight and is not easy to precipitate. DETAILED DESCRIPTION

[0018] The following is a preferred implementation of the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. For ordinary technicians in this technical field, all other embodiments obtained by ordinary technicians in this field without creative work without departing from the principle of the embodiment of the present invention are within the scope of protection of the present invention.

[0019] The following parts are by mass unless otherwise specified;

[0020] Example 1: S1: Take 22 parts of lactic acid, pre-treat at 120°C for 0.5h, add 12 parts of anacardic acid, 6 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heat at 110°C under reduced pressure for 0.5h, heat to 130°C, heat for 0.5h, heat to 160°C, add 2 parts of malic acid, polycondense under reduced pressure for 24h, add dichloromethane and stir evenly, add methanol solution and stir evenly, centrifuge and precipitate, and dry to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid;

[0021] S2: Take 10 parts of mica powder, 60 parts of water, 60 parts of ethanol, 0.4 parts of aminosilane coupling agent, 2 parts of vinyl silane coupling agent, stir at 50°C for 5h, filter and dry to obtain modified mica powder; take 10 parts of modified mica powder, 60 parts of water, 60 parts of acetic acid, 2 parts of glutaraldehyde, 0.7 parts of D-sorbitol, stir at 50°C for 3h, add 18 parts of polymethyl methacrylate, 0.01 parts of initiator azobisisobutyronitrile, heat at 70°C for 3h, filter and dry to obtain modified filler;

[0022] S3: Take the same mass of poly (L)-lactic acid and poly (D)-lactic acid, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B respectively; add methanol 8 times the mass of solution A and solution B respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0023] S4: 100 parts of a polylactic acid composition, 30 parts of polybutylene adipate, 25 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0024] Example 2: S1: Take 20 parts of lactic acid, pre-treat at 120°C for 0.5h, add 10 parts of anacardic acid, 5 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heat at 110°C under reduced pressure for 0.5h, heat to 130°C, heat for 0.5h, heat to 160°C, add 1 part of malic acid, polycondense under reduced pressure for 24h, add dichloromethane and stir evenly, add methanol solution and stir evenly, centrifuge and precipitate, and dry to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid;

[0025] S2: Take 10 parts of mica powder, 60 parts of water, 60 parts of ethanol, 0.2 parts of aminosilane coupling agent, 2 parts of vinyl silane coupling agent, stir at 50°C for 5 hours, filter and dry to obtain modified mica powder; take 10 parts of modified mica powder, 60 parts of water, 60 parts of acetic acid, 1 part of glutaraldehyde, 0.5 parts of D-sorbitol, stir at 50°C for 3 hours, add 20 parts of polymethyl methacrylate and 0.01 parts of initiator azobisisobutyronitrile, heat at 70°C for 3 hours, filter and dry to obtain modified filler;

[0026] S3: Take the same mass of poly (L)-lactic acid and poly (D)-lactic acid, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B respectively; add methanol 10 times the mass of solution A and solution B respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0027] S4: 100 parts of a polylactic acid composition, 30 parts of polybutylene adipate, 20 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0028] Example 3: S1: Take 25 parts of lactic acid, pre-treat at 120°C for 0.5h, add 15 parts of anacardic acid, 8 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heat at 110°C under reduced pressure for 0.5h, heat to 130°C, heat for 0.5h, heat to 160°C, add 2 parts of malic acid, polycondense under reduced pressure for 24h, add dichloromethane and stir evenly, add methanol solution and stir evenly, centrifuge and precipitate, and dry to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid;

[0029] S2: Take 10 parts of mica powder, 60 parts of water, 60 parts of ethanol, 0.5 parts of aminosilane coupling agent, 1 part of vinyl silane coupling agent, stir at 50°C for 5 hours, filter and dry to obtain modified mica powder; take 10 parts of modified mica powder, 60 parts of water, 60 parts of acetic acid, 1 part of glutaraldehyde, 0.5 parts of D-sorbitol, stir at 50°C for 3 hours, add 15 parts of polymethyl methacrylate and 0.01 parts of initiator azobisisobutyronitrile, heat at 70°C for 3 hours, filter and dry to obtain modified filler;

[0030] S3: Take the same mass of poly (L)-lactic acid and poly (D)-lactic acid, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B respectively; add methanol 10 times the mass of solution A and solution B respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0031] S4: 100 parts of a polylactic acid composition, 35 parts of polybutylene adipate, 25 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0032] Comparative Example 1 (changing the amount of each raw material added in the polylactic acid, and the other method steps are consistent with Example 1): S1: Take 30 parts of lactic acid, pre-treat at 120°C for 0.5h, add 5 parts of anacardic acid, 3 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heat at 110°C under reduced pressure for 0.5h, heat to 130°C, heat for 0.5h, heat to 160°C, add 5 parts of malic acid, polycondense under reduced pressure for 24h, add dichloromethane and stir evenly, add methanol solution and stir evenly, centrifuge and precipitate, and dry to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid;

[0033] S2: Take 10 parts of mica powder, 60 parts of water, 60 parts of ethanol, 0.4 parts of aminosilane coupling agent, 2 parts of vinyl silane coupling agent, stir at 50°C for 5h, filter and dry to obtain modified mica powder; take 10 parts of modified mica powder, 60 parts of water, 60 parts of acetic acid, 2 parts of glutaraldehyde, 0.7 parts of D-sorbitol, stir at 50°C for 3h, add 18 parts of polymethyl methacrylate, 0.01 parts of initiator azobisisobutyronitrile, heat at 70°C for 3h, filter and dry to obtain modified filler;

[0034] S3: Take the same mass of poly (L)-lactic acid and poly (D)-lactic acid, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B respectively; add methanol 8 times the mass of solution A and solution B respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0035] S4: 100 parts of a polylactic acid composition, 30 parts of polybutylene adipate, 25 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0036] Comparative Example 2 (changing the mass ratio of poly (L)-lactic acid and poly (D)-lactic acid in the poly (lactic acid composition), and the remaining steps are consistent with those in Example 1): S1: taking 22 parts of lactic acid, pre-treating at 120°C for 0.5h, adding 12 parts of anacardic acid, 6 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heating at 110°C under reduced pressure for 0.5h, heating to 130°C, heating for 0.5h, heating to 160°C, adding 2 parts of malic acid, poly-under reduced pressure for 24h, adding dichloromethane and stirring evenly, adding methanol solution and stirring evenly, centrifuging and precipitating, and drying to obtain poly (lactic acid); when the lactic acid is L-lactic acid, the obtained poly (lactic acid) is poly (L)-lactic acid; when the lactic acid is D-lactic acid, the obtained poly (lactic acid) is poly (D)-lactic acid;

[0037] S2: Take 10 parts of mica powder, 60 parts of water, 60 parts of ethanol, 0.4 parts of aminosilane coupling agent, 2 parts of vinyl silane coupling agent, stir at 50°C for 5h, filter and dry to obtain modified mica powder; take 10 parts of modified mica powder, 60 parts of water, 60 parts of acetic acid, 2 parts of glutaraldehyde, 0.7 parts of D-sorbitol, stir at 50°C for 3h, add 18 parts of polymethyl methacrylate, 0.01 parts of initiator azobisisobutyronitrile, heat at 70°C for 3h, filter and dry to obtain modified filler;

[0038] S3: Take poly (L)-lactic acid and poly (D)-lactic acid in a mass ratio of 2:1, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B; add methanol 8 times the mass of solution A and solution B, respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0039] S4: 100 parts of a polylactic acid composition, 30 parts of polybutylene adipate, 25 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0040] Comparative Example 3 (changing the ratio of raw materials in the polylactic acid composite material, the remaining method steps are consistent with Example 1): S1: Take 22 parts of lactic acid, pre-treat at 120°C for 0.5h, add 12 parts of anacardic acid, 6 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heat at 110°C under reduced pressure for 0.5h, heat to 130°C, heat for 0.5h, heat to 160°C, add 2 parts of malic acid, polycondense under reduced pressure for 24h, add dichloromethane and stir evenly, add methanol solution and stir evenly, centrifuge and precipitate, and dry to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid;

[0041] S2: Take 10 parts of mica powder, 60 parts of water, 60 parts of ethanol, 0.4 parts of aminosilane coupling agent, 2 parts of vinyl silane coupling agent, stir at 50°C for 5h, filter and dry to obtain modified mica powder; take 10 parts of modified mica powder, 60 parts of water, 60 parts of acetic acid, 2 parts of glutaraldehyde, 0.7 parts of D-sorbitol, stir at 50°C for 3h, add 18 parts of polymethyl methacrylate, 0.01 parts of initiator azobisisobutyronitrile, heat at 70°C for 3h, filter and dry to obtain modified filler;

[0042] S3: Take the same mass of poly (L)-lactic acid and poly (D)-lactic acid, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B respectively; add methanol 8 times the mass of solution A and solution B respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0043] S4: 100 parts of a polylactic acid composition, 40 parts of polybutylene adipate, 15 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0044] Comparative Example 4 (the preparation method of the modified filler is changed, and the remaining steps are consistent with Example 1): S1: Take 22 parts of lactic acid, pre-treat at 120°C for 0.5h, add 12 parts of anacardic acid, 6 parts of polyethylene glycol, 0.2 parts of stannous isooctanoate, and 0.03 parts of p-toluenesulfonic acid monohydrate, heat at 110°C under reduced pressure for 0.5h, heat to 130°C, heat for 0.5h, heat to 160°C, add 2 parts of malic acid, polycondense under reduced pressure for 24h, add dichloromethane and stir evenly, add methanol solution and stir evenly, centrifuge and precipitate, and dry to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly-L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly-D-lactic acid;

[0045] S2: Take 10 parts of mica powder, 0.7 parts of D-sorbitol, and 18 parts of polymethyl methacrylate, mix them, and obtain a modified filler;

[0046] S3: Take the same mass of poly (L)-lactic acid and poly (D)-lactic acid, dissolve them in chloroform (1 g / mL) to obtain solution A and solution B respectively; add methanol 8 times the mass of solution A and solution B respectively, perform reverse precipitation purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform (1 g / mL), stir for 4 hours, volatilize, and dry to obtain a polylactic acid composition;

[0047] S4: 100 parts of a polylactic acid composition, 30 parts of polybutylene adipate, 25 parts of a modified filler, and 0.1 parts of an antioxidant are mixed evenly, and melt-blended, extruded, and granulated at 245° C. to obtain a polylactic acid composite material.

[0048] In the above embodiments, the test methods used are conventional methods unless otherwise specified; the raw materials used are commercially available unless otherwise specified, and the sources of the raw materials are as follows: ethanol (CAS: 64-17-5); azobisisobutyronitrile (CAS: 78-67-1); vinyl silane coupling agent (CAS: 2768-02-7); stannous isooctanoate (S3252, Sigma-Aldrich); p-toluenesulfonic acid monohydrate (CAS: 6192-52-5); antioxidant (antioxidant 1010, S67391, Shanghai Yuanye); L-lactic acid (S11075, Shanghai Yuanye); D-lactic acid (S70034, Shanghai Yuanye); anacardic acid (CAS: 16611-84-0); polyethylene glycol ( Carboxyl-polyethylene glycol-hydroxyl, product number: 80030901, Carbon Water Technology); malic acid (CAS: 6915-15-7); dichloromethane (CAS: 75-09-2); methanol (CAS: 67-56-1); mica powder (2000 mesh, Hubei Shishun Biotechnology Co., Ltd.); aminosilane coupling agent (CAS: 919-30-2); acetic acid (CAS: 64-19-7); glutaraldehyde (CAS: 111-30-8); D-sorbitol (T25107, Shanghai Yuanye); polymethyl methacrylate (S30622, Shanghai Yuanye); trichloromethane (CAS: 67-66-3); polybutylene adipate (A103871, Zhengzhou Alpha Chemical Co., Ltd.).

[0049] Experiment: Take the polylactic acid composite materials prepared in Examples 1 to 3 and Comparative Examples 1 to 4, dry them, add them into a 3D printing consumable extruder, set the extrusion temperature at 240°C, and control the consumable diameters to be 1.75 mm; control the printing temperature to 240°C, the hot bed temperature to 90°C, and print the 1B type test specimens in accordance with GB / T 1040.2-2006; test the flexural strength and Vicat softening temperature; see the table below for specific data;

[0050]

[0051] Conclusion: Comparative Example 1 changes the amount of each raw material added in polylactic acid, and the added amount of anacardic acid and polyethylene glycol is small, and the performance decreases. It can be seen that the ratio of polylactic acid raw materials needs to be controlled; Comparative Example 2 changes the mass ratio of poly-L-lactic acid and poly-D-lactic acid in the polylactic acid composition, and the performance decreases significantly; Comparative Example 3 changes the ratio of raw materials in the polylactic acid composite material, polybutylene adipate is increased, and the modified filler is reduced. Due to compatibility and other problems, the performance decreases significantly. It can be seen that the ratio of raw materials of the polylactic acid composite material is also of great significance; Comparative Example 4 changes the preparation method of the modified filler, and directly adds mica powder, D-sorbitol, and polymethyl methacrylate as modified fillers, and the performance is not as good as the embodiment; In summary, the polylactic acid composite material prepared by the present invention has good mechanical properties, strong toughness, and good heat resistance.

[0052] Finally, it should be noted that the above is only a preferred embodiment of the present invention, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the spirit and principle of the present invention and within the technical scope disclosed in this application should be included in the protection scope of this application; in the absence of conflict, the embodiments of this application and the features in the embodiments can be combined with each other. Therefore, the protection scope of this application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a polylactic acid composite material based on 3D printing, The following steps are involved: S1: Take mica powder, water, ethanol, aminosilane coupling agent, vinylsilane coupling agent, stir, filter, and dry to obtain modified mica powder; Take modified mica powder, water, acetic acid, glutaraldehyde, and D-sorbitol, stir at 40-60°C for 2-3 hours, add polymethyl methacrylate and initiator, heat at 65-75°C for 2-3 hours, filter and dry to obtain modified filler; S2: Take poly (L)-lactic acid and poly (D)-lactic acid in a mass ratio of 1:(0.8-1.2), dissolve them in chloroform, respectively, to obtain solution A and solution B; add methanol, respectively, reverse precipitation and purification, separate and filter the precipitation, volatilize, and dry to obtain substance A and substance B respectively; mix to obtain a mixture, add chloroform and stir for 3-4h, volatilize, and dry to obtain a polylactic acid composition; S3: taking a polylactic acid composition, polybutylene adipate, a modified filler, and an antioxidant, mixing them evenly, and melt-blending and extruding them at 240-250° C. to obtain a polylactic acid composite material; The preparation steps of the poly L-lactic acid and poly D-lactic acid are as follows: taking 20-25 parts of lactic acid, pre-treating it, adding 10-15 parts of anacardic acid, 5-8 parts of polyethylene glycol, 0.1-0.3 parts of stannous isooctanoate, and 0.03-0.05 parts of p-toluenesulfonic acid monohydrate, heating at 110-115° C. under reduced pressure for 0.5-1h, heating to 130-135° C., heating for 0.5-1h, heating to 160-165° C., adding 1-2 parts of malic acid, polycondensing under reduced pressure for 24-25h, adding dichloromethane and stirring evenly, adding methanol solution and stirring evenly, centrifuging and precipitating, and drying to obtain polylactic acid; when the lactic acid is L-lactic acid, the obtained polylactic acid is poly L-lactic acid; when the lactic acid is D-lactic acid, the obtained polylactic acid is poly D-lactic acid.

2. The method for preparing a polylactic acid composite material based on 3D printing according to claim 1, characterized in that: The modified mica powder comprises the following raw materials, calculated by weight: 10 parts of mica powder, 50-60 parts of water, 50-60 parts of ethanol, 0.2-0.5 parts of aminosilane coupling agent, and 1-2 parts of vinylsilane coupling agent; the modified filler comprises the following raw materials, calculated by weight: 10 parts of modified mica powder, 50-60 parts of water, 50-60 parts of acetic acid, 1-2 parts of glutaraldehyde, 0.5-0.8 parts of D-sorbitol, 15-20 parts of polymethyl methacrylate, and 0.01-0.02 parts of initiator.

3. The method for preparing a polylactic acid composite material based on 3D printing according to claim 1, characterized in that: The polylactic acid composite material comprises the following raw materials, calculated by weight: 100 parts of a polylactic acid composition, 30-35 parts of polybutylene adipate, 20-25 parts of a modified filler, and 0.1-0.2 parts of an antioxidant.

4. A polylactic acid composite material prepared according to the method for preparing a polylactic acid composite material based on 3D printing according to any one of claims 1 to 3.

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