An amino-functionalized epoxy cardanol glycidyl ether compatibilizer and its preparation and application

Abstract

The present invention discloses an amino-functionalized epoxy cashew phenol glycidyl ether (NH2-NC514) compatibilizer and its preparation and application, belonging to the technical field of plastic additives. The NH2-NC514 is prepared by first carrying out a self-polymerization reaction on NC514 and then carrying out a grafting reaction with hydrolyzed KH550. When used as a compatibilizer and mixed with polylactic acid and bamboo fiber, the active groups such as epoxy groups, hydroxyl groups, and amino groups in its structure can react with the polar groups on the surface of BFs and the end groups of the PLA molecular chain to reduce the hydrophilicity of BFs and improve the interfacial compatibility with the PLA matrix, obtaining a fully biodegradable bamboo-plastic composite material with excellent processing fluidity and mechanical properties. When the composite material is applied to 3D printing, the prepared 3D printing products not only have excellent mechanical properties, thermal properties, appearance quality, and processability, but also have excellent anti-aging properties and service stability.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic additives, and particularly to an aminated epoxy cardanol glycidyl ether compatibilizer and its preparation and application. Background Art

[0002] The polylactic acid / bamboo fiber composite material used for fused deposition modeling (FDM) 3D printing filaments has environmental sustainability, light weight and high strength, unique appearance and texture, and lower cost. With its flexible design and manufacturing capabilities, it can meet the needs of the fine manufacturing industry for complex structural parts and personalized and differentiated products, and has good commercial prospects. However, the application of continuous plant fiber-reinforced composite materials in 3D printing technology is still rare. This is mainly because a large number of polar hydroxyl groups (alcohol hydroxyl groups and phenolic hydroxyl groups) on the surface of bamboo fibers (BFs), strong water absorption and intermolecular forces make their dispersibility poor during thermoplastic processing; when melt-blended with hydrophobic polylactic acid (PLA) resin, the interfacial compatibility is poor; the processing fluidity and mechanical properties are poor when preparing composite materials with high fiber content, and problems such as filament breakage and nozzle blockage occur during extrusion and 3D printing, affecting the dimensional stability and printing accuracy of the product.

[0003] Researchers have now conducted extensive research on the performance modification of fiber-reinforced composite materials, mainly focusing on the surface treatment of fibers and the modification of polymer matrices. The purpose of fiber surface treatment is to reduce the surface polarity of fibers and increase the surface roughness, thereby improving the interfacial bonding with the polymer matrix. It includes physical methods such as steam explosion and high-temperature carbonization, and chemical methods such as alkali treatment and silane coupling agent treatment. However, physical methods require high equipment requirements and high energy consumption; chemical methods have cumbersome steps and it is difficult to achieve industrial production.

[0004] Directly introducing a modifier during the melt blending stage has now become the first choice for green and efficient preparation of modified new materials. Thermodynamically immiscible polymer blends are often effectively compatibilized by non-in-situ and in-situ reactive compatibilizers. Although non-in-situ reactive compatibilizers can enable fiber-reinforced composite materials to exhibit excellent physical properties and processing properties through physical effects such as reducing interfacial tension and strengthening interfacial adhesion. However, during thermoplastic processing, due to the lack of chemical reactions, depolymerization and entanglement of macromolecular chains are likely to occur; when the compatibilizer is in excess, agglomeration is likely to occur, forming a phase separation structure, and the compatibilization efficiency is low.

[0005] By using an in-situ reactive compatibilizer with reactive functional groups (such as acid anhydride, isocyanate, etc.), its lower melt viscosity can be diffused to the surface of the blend efficiently in a short time. The graft copolymer is formed by the reaction of the active groups with the polar groups on the fiber surface and the end groups of the matrix, thereby realizing the surface treatment of the fiber and the modification of the polymer matrix. However, there is often a problem that the mechanical properties of the composite material decrease due to the migration of the compatibilizer molecules in a short time, and the service stability of the product in high-temperature and humid environments cannot be ensured.

[0006] Therefore, there is an urgent need to develop a bio-based compatibilizer with high synthesis efficiency, high reaction activity, good compatibility modification and resistance to migration. Summary of the Invention

[0007] The purpose of the present invention is to provide an amino-functionalized epoxy cardanol glycidyl ether compatibilizer and its preparation and application to solve the problems existing in the above-mentioned prior art. The present invention uses epoxy cardanol glycidyl ether (NC514) as a raw material, initiates the self-polymerization of NC514 and introduces amino groups for graft modification to form a three-dimensional network polymer, and improves the intermolecular interaction force by increasing the molecular weight of NC514 and the chemical sites for reacting with BFs and PLA. By controlling the self-polymerization and graft reaction conditions, the molecular structure of the compatibilizer is regulated. The adjustment of the molecular structure can enhance the migration resistance performance and the service stability of the composite material, and thus provides a promising strategy for realizing the thermoplastic processing of high-filled bamboo-plastic composites and the preparation of high-performance 3D printing products.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] One of the technical solutions of the present invention: An amino-functionalized epoxy cardanol glycidyl ether (abbreviated as NH2-NC514), the structural formula is:

[0010]

[0011] Among them, represents -(CH2)6- (alkane chain).

[0012] Among them, m is any natural number; n is any natural number.

[0013] The above structural formula actually represents the repeating unit of the NH2-NC514 polymer, reflecting the chemical sites that can undergo reactions (the structural formula indicating the chemical sites that can undergo reactions is as shown in Figure 1 ). Among them, the reaction sites in the red box react with poly-NC514 (the structural formula indicating the chemical sites that can undergo reactions is as shown in Figure 2Continue to react and connect at the reaction sites within the red box in a) as shown in Figure 2 Continue to react and connect at the reaction sites within the blue circle in b) as shown in the hydrolyzed KH550 (the structural formula indicating the chemical sites capable of reacting is as shown in

[0014] The second technical solution of the present invention: A preparation method of the above-mentioned amino-functionalized epoxy cashew phenol glycidyl ether, comprising the following steps:

[0015] Hydrolyze 3-aminopropyltriethoxysilane (KH550) to obtain hydrolyzed KH550;

[0016] Utilize a cationic initiator to initiate the self-polymerization of epoxy cashew phenol glycidyl ether (NC514) to obtain poly-epoxy cashew phenol glycidyl ether (poly-NC514);

[0017] Using the poly-NC514 and the hydrolyzed KH550 as reactants, conduct a grafting reaction to obtain the amino-functionalized epoxy cashew phenol glycidyl ether (NH2-NC514).

[0018] Furthermore, the step of hydrolyzing KH550 includes: Dissolve KH550 in an ethanol solution, stir magnetically for 30 - 90 min, preferably 30 min, to complete the hydrolysis reaction and obtain the hydrolyzed KH550.

[0019] Preferably, the volume fraction of the ethanol solution is 60%.

[0020] Preferably, the dissolution concentration of KH550 in the ethanol solution is 2 wt.% (i.e., the concentration of KH550 in the mixed system after dissolution is 2 wt.%).

[0021] Preferably, the temperature of the hydrolysis reaction is room temperature.

[0022] Furthermore, the structural formula of the hydrolyzed KH550 is: (i.e., Figure 2 b) as shown in

[0023] Furthermore, the step of utilizing a cationic initiator to initiate the self-polymerization of NC514 includes:

[0024] Dissolve the cationic initiator and NC514 in a solvent, stir vigorously at room temperature for 5 - 10 min to initiate the self-polymerization of NC514 and obtain the poly-NC514 (the structural formula is as shown in Figure 2 a) as shown in

[0025] Preferably, the solvent is a mixture of acetone, ethanol, xylene and n-butanol in a volume ratio of 7:3 or propylene glycol methyl ether, and most preferably acetone. Acetone has good solubility as a solvent and fast volatilization rate.

[0026] Preferably, the cationic initiator is boron trifluoride ethylamine complex (BF3NH2Et).

[0027] Preferably, the dosage of the cationic initiator is 1-2 wt.% of the dosage of NC514.

[0028] Preferably, the temperature of the self-polymerization is room temperature.

[0029] Among them, the chemical reaction formula for preparing poly-NC514 is as Figure 3 shown. The in both NC514 and poly-NC514 represents an alkane chain -(CH2)6-.

[0030] From Figure 3 the reaction formula, it can be seen that the protons generated by BF3NH2Et can induce the opening of the epoxy ring, thereby carrying out the self-polymerization of NC514 (or ESO).

[0031] Preferably, the weight-average molecular weight of the poly-NC514 is 900-1500 g / mol.

[0032] Furthermore, the step of carrying out the grafting reaction with the poly-NC514 and the hydrolyzed KH550 as reactants includes: dissolving the poly-NC514 in the hydrolyzed KH550, stirring for 30-60 min, completing the grafting reaction (amino grafting modification reaction), and obtaining the NH2-NC514.

[0033] Preferably, the mass ratio of the poly-NC514 to the hydrolyzed KH550 is 3-1:1-3, and more preferably 3:1, 1:1 or 1:3.

[0034] Preferably, the temperature of the grafting reaction is room temperature.

[0035] Preferably, after completing the grafting reaction, it further includes the operation of drying the grafting reaction product in a vacuum oven at 80 °C for 12 h.

[0036] Preferably, the weight-average molecular weight of the NH2-NC514 is 5000-12000 g / mol, and more preferably 8000 g / mol.

[0037] The reaction conditions of the self-polymerization and grafting reactions can affect the molecular weight of the product NH2-NC514. By adjusting the reaction conditions of the self-polymerization (including the time of the self-polymerization reaction and the dosage of the cationic initiator), and the reaction conditions of the grafting reaction (including the dosage ratio of poly-NC514 to hydrolyzed KH550 and the time of the grafting reaction), NH2-NC514 with any molecular weight within the range of 5000-12000 g / mol can be obtained.

[0038] Technical solution three of the present invention: Application of the above-mentioned amino-functionalized epoxy cardanol glycidyl ether as a compatibilizer in the preparation of 3D printing composites.

[0039] Technical solution four of the present invention: A 3D printing composite material, by mass, the raw materials include: 70 parts of PLA (polylactic acid), 30 parts of BFs (bamboo fiber), and 2-8 parts of a compatibilizer; the compatibilizer is the above-mentioned amino-functionalized epoxy cardanol glycidyl ether.

[0040] NH2-NC514, as a compatibilizer for the matrix materials (PLA and BFs) of 3D printing composites, endows the matrix materials with excellent interfacial compatibility, mechanical properties, processing properties, and service stability.

[0041] Preferably, the dosage of the compatibilizer is 4-8 parts.

[0042] Technical solution five of the present invention: A method for preparing the above-mentioned 3D printing composite material, comprising the following steps:

[0043] First, mix PLA, BFs, and the compatibilizer at room temperature, and then perform internal mixing to obtain the 3D printing composite material.

[0044] Further, the specific operation of the room temperature mixing is: stirring and mixing at a speed of 60 rpm for 10-30 min under room temperature conditions; the specific operation of the internal mixing is: stirring and mixing at a speed of 60 rpm for 8 min under the condition of 190 °C.

[0045] Technical solution six of the present invention: A method for preparing a 3D printing product using the above-mentioned 3D printing composite material, comprising the following steps:

[0046] Crush the 3D printing composite material and then melt and extrude it to obtain a thermoplastic filament; perform 3D printing on the thermoplastic filament to obtain a 3D printing product.

[0047] Preferably, the temperature of the melt extrusion is 175-180 °C; the diameter of the thermoplastic filament is 1.75 ± 0.03 mm.

[0048] Further, before the mixed material is crushed and melt-extruded, it also includes an operation of vacuum drying the crushed 3D printing composite material at 80°C for 12 h to remove the residual moisture in the 3D printing composite material.

[0049] Preferably, the 3D printing is carried out in an FDM printer, and the parameter settings of the FDM printer are as follows: nozzle temperature 190 - 220°C, platform temperature 60 - 80°C, printing speed 40 - 80 mm / s, layer thickness 0.05 - 0.25 mm; the layer thickness is most preferably 0.1 mm.

[0050] The seventh technical solution of the present invention: a 3D printing product prepared by the above preparation method.

[0051] The material properties of continuous plant fiber-reinforced composites do not match well with 3D printing technology, so their application in 3D printing technology is still very rare. In the present invention, amino-epoxy cashew phenol glycidyl ether, which can diffuse to the surface of the blend in a short time and with high efficiency, is directly added as a compatibilizer during melt blending, simultaneously realizing surface treatment of the fibers and modification of the polymer matrix, and preparing a fully bio-based degradable bamboo-plastic composite material (3D printing composite material) with excellent processing fluidity and mechanical properties. When the 3D printing composite material is used for 3D printing, the 3D printing product prepared by adjusting the nozzle temperature, printing layer height, printing speed and filling rate not only has excellent mechanical properties, thermal properties, appearance quality and processability, but also has excellent anti-aging performance and service stability.

[0052] The present invention discloses the following technical effects:

[0053] The present invention provides a novel bio - based compatibilizer, amino - modified epoxy cashew phenol glycidyl ether (NH2 - NC514), for PLA / BFs composites. The present invention prepares a reactive and migration - resistant compatibilizer NH2 - NC514 with a three - dimensional network structure having high synthesis efficiency, high reaction activity, good compatibilizing modification, and good migration resistance through the method of initiating the self - polymerization of NC514 and introducing amino groups for graft modification. By increasing the molecular weight of the compatibilizer and the chemical sites for reacting with BFs and PLA, the intermolecular interaction force is enhanced. The molecular structure (molecular weight) of the compatibilizer is regulated by controlling the self - polymerization and graft reaction conditions. The adjustment of the molecular structure (molecular weight) can enhance the migration resistance performance while also enhancing the service stability of the composite material. When the NH2 - NC514 prepared by the present invention is used as a compatibilizer for PLA / BFs composites, the reaction of active groups such as epoxy groups, hydroxyl groups, and amino groups in the structure with the polar groups on the surface of BFs and the end groups of the PLA molecular chain can not only promote the effective dispersion of PLA and BFs, ensuring the uniformity of the composite material; but also enhance the interfacial compatibility through chemical reactions, reduce the interfacial tension, and improve the bonding strength; moreover, it can play a role in the cross - linking and curing process, constructing a stable three - dimensional network, enhancing the mechanical and thermal stability of the composite material, and preparing a fully bio - based degradable bamboo - plastic composite material with excellent processing fluidity and mechanical properties. Applying the above - mentioned composite material to 3D printing, the prepared 3D printing products not only have excellent mechanical properties, thermal properties, appearance quality, and processability, but also have excellent anti - aging performance and service stability. It overcomes the problem that high - fiber filling cannot achieve thermoplastic processing and realizes the preparation of bamboo - plastic 3D printing products with excellent and stable performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0055] Figure 1 is the structural formula of NH2 - NC514;

[0056] Figure 2 are the structural formulas of poly - NC514 and hydrolyzed KH550, where a is poly - NC514 and b is hydrolyzed KH550;

[0057] Figure 3 is the chemical reaction formula for preparing poly - NC514 by self - polymerization;

[0058] Figure 4 is the chemical reaction formula for preparing NH2 - ESO by self - polymerization;

[0059] Figure 5 Reaction mechanism for preparing 3D printing composite materials;

[0060] Figure 6 FTIR spectra of NH2-NC514 prepared in Example 1, NH2-ESO prepared in Comparative Example 1, and raw materials NC514 and ESO;

[0061] Figure 7 SEM images of BFs extracted from 3D printing composite materials prepared in Application Example 1, Comparative Application Example 1, and 3. Among them, (a)-(c) are the surface SEM images of BFs (extracted from Comparative Application Example 3), BFs / 4NH2-ESO (extracted from Comparative Application Example 1), and BFs / 4NH2-NC514 (extracted from Application Example 1), respectively;

[0062] Figure 8 Curve-resolved XPS C1s spectra of BFs extracted from 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3. Among them, (a)-(e) are BFs (extracted from Comparative Application Example 3), BFs / 4NH2-ESO (extracted from Comparative Application Example 1), BFs / 4NH2-ESO (extracted from Comparative Application Example 2), BFs / 4NH2-NC514 (extracted from Application Example 1), and BFs / 4NH2-NC514 (extracted from Application Example 2), respectively;

[0063] Figure 9 DSC second heating curves of 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3;

[0064] Figure 10 DMA curves of 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3. Among them, (a) is the storage modulus and (b) is the loss factor;

[0065] Figure 11 Rheological property test curves of 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3. Among them, (a) is the complex viscosity and (b) is the storage modulus;

[0066] Figure 12SEM images of the surface and fracture surface after impact fracture of the impact splines prepared from the 3D printing composite materials in Application Examples 1-2 and Comparative Application Example 1-3. Among them, (a)-(e) are the SEM images of the fracture surfaces of PLA / BFs, PLA / BFs / 4NH2-ESO, PLA / BFs / 8NH2-ESO, PLA / BFs / 4NH2-NC514, and PLA / BFs / 8NH2-NC514 respectively, and (a’)-(e’) are the SEM images of the surfaces of PLA / BFs, PLA / BFs / 4NH2-ESO, PLA / BFs / 8NH2-ESO, PLA / BFs / 4NH2-NC514, and PLA / BFs / 8NH2-NC514 respectively;

[0067] Figure 13 Comparison diagram of the thermoplastic filaments prepared from the 3D printing composite materials in Application Example 1 and Comparative Application Example 1. Among them, the left is Application Example 1 and the right is Comparative Application Example 1;

[0068] Figure 14 Printing process and product diagrams when the thermoplastic filaments prepared from the 3D printing composite materials in Application Example 1 are 3D printed. Among them, (a) is the printing progress of 20%, (b) is the printing progress of 40%, (c) is the printing progress of 60%, (d) is the printing progress of 80%, (e) is the printing progress of 100%, and (f)-(g) are the product diagrams;

[0069] Figure 15 Heat resistance comparison between the sheet prepared from the 3D printing composite material PLA / BFs / 4NH2-NC514 in Application Example 1 and the PLA sheet;

[0070] Figure 16 Schematic diagram of extruding thermoplastic filaments by a single-screw extruder and then performing 3D printing. Detailed implementation manners

[0071] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0072] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0073] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0074] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the description of this invention, which will be obvious to those skilled in the art. Other embodiments obtained from the description of this invention will be obvious to those skilled in the art. The description and examples of this invention are merely exemplary.

[0075] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0076] The raw materials and reagents used in the specific embodiments of this invention are all commercially available products. Among them, PLA (4032D) is commercially obtained from NatureWorks, USA, with a weight-average molecular weight (Mw) of 17.62×10 4 g / mol, a melt flow rate of 7 g / 10 min, a melting temperature of 190 °C, and a weight of the weight in the melt index test of 2.16 kg; the BFs have a diameter of 0.1 - 1 μm and a length of 5 - 50 μm, and are purchased from Weihua Spice Factory, Mujiang, Shuangshui Town, Xinhui District, Jiangmen City, Guangdong Province, China; NC514 is directly used after being purchased from Cray Valley, USA, with a CAS number of 68390-54-5 and a weight-average molecular weight (Mw) of 537 g / mol; BF3NH2Et is provided by Shanghai Sigma-Aldrich; KH550 is purchased from Beijing Mreda; acetone and ethanol are provided by Beijing Chemical Reagent Research Institute.

[0077] The "parts" mentioned in the specific embodiments of this invention refer to "parts by mass" unless otherwise specified.

[0078] The "room temperature" mentioned in the specific embodiments of this invention refers to 15 - 30 °C unless otherwise specified.

[0079] The rotation speed of the "magnetic stirring" involved in the specific embodiments of this invention is 150 r / min, and the rotation speed of the "vigorous stirring" involved is 280 r / min.

[0080] Example 1

[0081] The preparation of NH2-NC514 is as follows:

[0082] S1. Dissolve KH550 in an ethanol solution with a volume concentration of 60% (the ethanol solution is prepared by mixing absolute ethanol and deionized water at a volume ratio of 3:2), and magnetically stir for 30 min at room temperature to complete the hydrolysis process, obtaining hydrolyzed KH550. Among them, the dissolution concentration of KH550 in the ethanol solution is 2 wt.%.

[0083] S2. Dissolve the cationic initiator BF3NH2Et and NC514 in acetone (as long as it can be completely dissolved, there is no specific requirement for the amount of acetone), and vigorously stir at room temperature for 5 min to initiate the self-polymerization of NC514, obtaining poly-NC514 (detected, the weight-average molecular weight is 1395 g / mol). Among them, the dosage of BF3NH2Et is 2 wt.% of the dosage of NC514.

[0084] S3. Dissolve poly-NC514 in hydrolyzed KH550, and continue to magnetically stir at room temperature for 30 min to carry out the grafting reaction. After the grafting reaction is completed, dry the reaction solution in a vacuum oven at 80 °C for 12 h to obtain NH2-NC514 (detected, the number-average molecular weight is about 8000 g / mol). Among them, the mass ratio of hydrolyzed KH550 to poly-NC514 is 1:1.

[0085] Comparative Example 1

[0086] The preparation of NH2-ESO is as follows:

[0087] S1. Dissolve KH550 in an ethanol solution with a volume concentration of 60% (the ethanol solution is prepared by mixing absolute ethanol and deionized water at a volume ratio of 3:2), and magnetically stir for 30 min at room temperature to complete the hydrolysis process, obtaining hydrolyzed KH550. Among them, the dissolution concentration of KH550 in the ethanol solution is 2 wt.%.

[0088] S2. Dissolve the cationic initiator BF3NH2Et and ESO (epoxidized soybean oil, the weight-average molecular weight is about 1000 g / mol) in acetone, and vigorously stir at room temperature for 5 min to initiate the self-polymerization of ESO, obtaining poly-ESO. Among them, the dosage of BF3NH2Et is 2 wt.% of the dosage of ESO.

[0089] S3. Dissolve poly-ESO in hydrolyzed KH550, and continue to magnetically stir at room temperature for 30 min to carry out the grafting reaction. After the grafting reaction is completed, dry the reaction solution in a vacuum oven at 80 °C for 12 h to obtain NH2-ESO. Among them, the mass ratio of hydrolyzed KH550 to poly-ESO is 1:1.

[0090] The chemical reaction formula for preparing NH2-ESO is as Figure 4 shown, where the represents an alkane chain, but does not represent the same alkane as in the NH2-NC514 structural formula.

[0091] Figure 6 are the infrared spectroscopy (FTIR) diagrams of NH2-NC514 prepared in Example 1 of the present invention, NH2-ESO prepared in Comparative Example 1, and the raw materials NC514 and ESO. From Figure 6 it can be observed that the characteristic peak of the carbonyl ester group C=O unique to the ESO and NH2-ESO structures appears at 1740 cm -1 ; while the characteristic peak of the benzene ring skeletal carbon-carbon double bond C=C unique to the NC514 and NH2-NC514 structures appears at 1580 cm -1 . The self-polymerization reaction of ESO and NC514 causes the bending vibration characteristic peak of C-O-C located at 850 cm -1 to change. The appearance of the stretching vibration characteristic peak of Si-O-C at 1030 cm -1 and the -OH characteristic peak at 3300 cm -1 indicate that KH550 is successfully grafted onto the surfaces of poly-ESO and poly-NC514 by hydrolysis, and NH2-ESO and NH2-NC514 are successfully prepared.

[0092] Application Example 1

[0093] Preparation of 3D printing composite materials, the steps are as follows:

[0094] S1. Raw material preparation: 70 parts of PLA, 30 parts of BFs, and 4 parts of NH2-NC514 (as a compatibilizer) prepared in Example 1;

[0095] S2. Mix PLA, BFs, and the compatibilizer at room temperature at a rotation speed of 60 rpm for 30 min, and then use a kneader to mix for 8 min at a rotation speed of 60 rpm and a temperature of 190 °C to obtain a mixed material, which is the 3D printing composite material, denoted as PLA / BFs / 4NH2-NC514.

[0096] Application Example 2

[0097] Compared with Application Example 1, the difference is only that the dosage of NH2-NC514 is 8 parts, and the prepared 3D printing composite material is denoted as PLA / BFs / 8NH2-NC514.

[0098] Comparative Application Example 1

[0099] Compared with Application Example 1, the difference is only that NH2-ESO prepared in Comparative Example 1 with the same mass is used to replace NH2-NC514 as the compatibilizer, and the prepared 3D printing composite material is denoted as PLA / BFs / 4NH2-ESO.

[0100] Comparative Application Example 2

[0101] Compared with Application Example 2, the difference is only that NH2-ESO prepared in Comparative Example 1 with the same mass is used instead of NH2-NC514 as the compatibilizer, and the prepared 3D printing composite material is denoted as PLA / BFs / 8NH2-ESO.

[0102] Comparative Application Example 3

[0103] Compared with Application Example 1, the difference is only that no compatibilizer is added, and the prepared 3D printing composite material is denoted as PLA / BFs.

[0104] Test Example 1

[0105] Using chloroform as the solvent, BFs were extracted from the 3D printing composite material (2 g) by Soxhlet extraction at 80 °C. After drying at 80 °C for 24 h, the surface microstructure and chemical analysis of the extracted BFs were carried out.

[0106] Test method: The change in the surface microstructure of the extracted BFs was observed using a scanning electron microscope (SEM), and the observation was carried out on a TESCAN VEGA 11 with an acceleration voltage of 10 kV.

[0107] The surface chemical properties of BFs were revealed by X-ray photoelectron spectroscopy (XPS). The XPS experiment was carried out on an ESCALAB 250Xi XPS instrument with an Al Kα radiation source. High-resolution atomic spectra were obtained, with an energy pass of 70.0 eV and an increment of 0.2 eV. The C1s spectrum was analyzed using XPS Peak4.0 software.

[0108] Test results: The test results are as Figure 7 and Figure 8 shown.

[0109] Figure 7 SEM images of BFs extracted from the 3D printing composite materials prepared in Application Example 1, Comparative Application Example 1, and 3 are shown, where (a)-(c) are the surface SEM images of BFs (extracted from Comparative Application Example 3), BFs / 4NH2-ESO (extracted from Comparative Application Example 1), and BFs / 4NH2-NC514 (extracted from Application Example 1), respectively. From Figure 7It can be seen that the BFs without compatibilizer show a rough fiber surface, while after adding compatibilizers NH2-ESO and NH2-NC514, a relatively smooth fiber surface can be observed. This is mainly because during the extraction process, lignin and hemicellulose on the fiber surface are removed, resulting in the appearance of grooved indentations. After adding the compatibilizer, the indentations are filled with the formed flexible layer of the compatibilizer. Due to the higher reactivity of the active groups in the NH2-NC514 structure with the polar groups on the BFs surface, NH2-NC514 is evenly attached to the BFs surface, and the fiber surface is smoother.

[0110] The reaction mechanism for preparing the 3D printing composite material (only the chemical sites where reactions may occur are shown) is as Figure 5 shown. As shown in the reaction mechanism for preparing the 3D printing composite material, during the melt compounding process, since NH2-NC514 and NH2-ESO are attached to the BFs surface and located at the interface between BFs and the PLA matrix, the following several reactions mainly occur: (1) The -OH groups of BFs can act as ring-opening agents for the epoxy groups in the compatibilizer structure to form covalent bonds between BFs and the compatibilizer; (2) The -OH groups of BFs can undergo substitution reactions with the -OH groups in the compatibilizer structure; (3) The epoxy groups in the compatibilizer structure react with the terminal -COOH or -OH groups of PLA to generate chemical bonds between the compatibilizer and PLA; (4) The amino groups in the compatibilizer structure undergo substitution reactions with the terminal -COOH groups of PLA.

[0111] Figure 8 Figure is the curve-resolved XPS C1s spectrogram of BFs extracted from the 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3 (BF and BFs in the figure represent the same meaning), where (a)-(e) are BFs (extracted from Comparative Application Example 3), BFs / 4NH2-ESO (extracted from Comparative Application Example 1), BFs / 4NH2-ESO (extracted from Comparative Application Example 2), BFs / 4NH2-NC514 (extracted from Application Example 1), and BFs / 4NH2-NC514 (extracted from Application Example 2). It can be Figure 8 seen that natural BFs have four typical C components, namely C1 (C-C / C-H), C2 (C-O), C3 (C=O / O-C-O), and C4 (O-C=O). Among them, C2 mainly comes from cellulose, and other components are closely related to non-cellulose substances such as hemicellulose and lignin. The ratio of C1:C2:C3:C4 in BFs is 1:1.09:0.41:0.03 ( Figure 8(a)). The C component ratio of PLA (the end groups of PLA can be ignored) is 1:1:0:1; the NH2-NC514 structure does not contain C3 and C4 components, and the NH2-ESO structure does not contain C3 components, resulting in a decrease and even disappearance of the C3 content with the increase in the amount of compatibilizer. Figure 8 (b)-(e)). With the increase in the amount of compatibilizer, the C1 content increases, which may be due to the grafting of the fatty chain in the compatibilizer structure and the -CH3 group of PLA. Since NH2-NC514 is uniformly attached to the surface of BFs, the C4 content of BFs / 8NH2-NC514 basically disappears.

[0112] Test Example 2

[0113] Crystallization Property Test

[0114] DSC (Differential Scanning Calorimetry) can measure the crystallinity of polymers. Crystallinity refers to the proportion of the crystalline region in the polymer and is one of the important parameters for evaluating the properties of polymers. Through DSC testing, the heat change during the crystallization process of polymers can be measured to evaluate the quality of the polymer crystallization performance.

[0115] Test Method: Using TA Instruments (TA2500), carried out under a N2 flow rate of 50 mL / min. Seal 7 mg of the 3D printing composite material samples prepared in Application Examples 1-2 and Comparative Application Examples 1-3 in a covered aluminum pan for testing. For the scan, the sample is heated from 30 °C to 200 °C at a rate of 10 °C / min and two consecutive scans are tested.

[0116] Test Results: The test results are as Figure 9 shown in Table 1.

[0117] Table 1 DSC Crystallization Data

[0118]

[0119]

[0120] Figure 9 The second heating curve of DSC for the 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3 (the meaning of BF in the figure is the same as that of BFs). From Figure 9As can be seen from Table 1, after being modified by the compatibilizer, the glass transition temperature (Tg), melting temperature (Tm), and crystallinity (Xc) of the 3D printing composite material show a downward trend with the increase of the compatibilizer content, while the cold crystallization temperature (Tcc) shows an upward trend, and the change trend of the material with NH2-NC514 as the compatibilizer is more obvious. The decrease in Tg usually means that the material can change from the glassy state to the high elastic state at a lower temperature, which makes the material more likely to deform when subjected to external forces, thus improving the toughness of the material. The decrease in Tm and the increase in Tcc help to reduce energy consumption, lower production costs and processing difficulties, and improve production efficiency. The lower crystallinity helps to improve the fluidity of the material, making it easier for the material to fill the mold or the extrusion head during processing such as injection molding and extrusion, reducing defects and rejection rates.

[0121] Test Example 3

[0122] Dynamic mechanical analysis

[0123] Test method: The 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3 were subjected to dynamic mechanical analysis (after crushing the composite materials, standard specimens with a shape of 40 mm × 10 mm × 1 mm were prepared by a micro-injection molding machine for experimental testing), carried out on a DMA7100 TA instrument, the tensile mode was 30 - 110 °C, the heating rate was 2 °C / min, and the frequency was 1 Hz.

[0124] Test results: The test results are shown in Table 2 and Figure 10 as follows.

[0125] Table 2 E’ and Tg of 3D printing composite materials

[0126]

[0127]

[0128] Figure 10 is the DMA curve of the 3D printing composite materials prepared in Application Examples 1-2 and Comparative Application Examples 1-3 (the meaning of BF in the figure is the same as that of BFs), where (a) is the storage modulus and (b) is the loss factor. From Table 2 and Figure 10It can be seen that when the compatibilizer content is 4 parts, the storage modulus (E’) of the composite material is greater than that of the PLA / BFs composite material modified without adding a compatibilizer; when the compatibilizer content is 8 parts, the E’ of the composite material is less than that of the PLA / BFs composite material modified without adding a compatibilizer. This is mainly because the epoxy groups in the compatibilizer can react with the polar groups of BFs and the terminal carboxyl groups of PLA to form a cross-linked network polymer, and the cross-linking will enhance the rigidity of the material, resulting in an increase in E’. Excessive compatibilizer can cure in the PLA matrix to form an elastomer, which has a significant impact on the toughness of PLA. The elastomer will destroy the dense structure of the amorphous region of PLA, thereby reducing the E’ of the material. The E’ value of PLA / BFs / NH2-NC514 is higher than that of PLA / BFs / NH2-ESO because NH2-NC514 can form a network structure with the PLA molecular chain, so that the composite material has a stronger ability to store elastic deformation. For Tg, the DSC (Table 1) method more directly reflects the change in heat capacity of the material during the glass transition process, while DMA focuses on the change in the mechanical properties (especially viscoelasticity) of the material. There are differences in the test principle, the physical quantities concerned, and the manifestation form of the curve between the two, but both can effectively measure the Tg of the material. The peak temperature of the loss factor in the DMA test is the Tg of the composite material, and the test results are basically the same as those of DSC. When the compatibilizer content is the same, the Tg of PLA / BFs / NH2-NC514 is lower than that of PLA / BFs / NH2-ESO.

[0129] Test Example 4

[0130] Mechanical Property Test

[0131] Test Method: After crushing the 3D printing composite material (the mixed material obtained after internal mixing) with a crusher, dumbbell-shaped tensile specimens (GB / T 1040-92) and impact specimens (GB / T 1843-2008) were made using a micro-injection molding machine at a barrel temperature of 200 °C and a mold temperature of 120 °C. After placing the dumbbell-shaped tensile specimens and impact specimens prepared from the 3D printing composite materials in Application Examples 1-3 and Comparative Application Examples 1-3 in the laboratory environment for 24 h, a tensile test was carried out using a universal testing machine according to GB / T1040.2-2006 (IDT ISO 527.2-2:1993), and the tensile speed was 10 mm / min. According to GB / T9341-2008 (IDT ISO 178-2001), a bending test was carried out using a universal testing machine, the test speed was 2 mm / min, and the specified deflection was 6 mm. In accordance with the requirements of GB / T 1843-2008 (IDT ISO 180-2000), a non-notch impact test was carried out using a cantilever beam impact testing machine with a 1J hammer.

[0132] Test Results: The test results are shown in Table 3.

[0133] Table 3 Mechanical property results of 3D printed composites

[0134]

[0135] Strength, toughness and stiffness are considered key factors characterizing the mechanical properties of composites. When selecting 3D printing materials, these properties must be carefully balanced. However, in most cases, strength and toughness are prioritized, especially in various general 3D printing applications. Selecting materials with high strength will ensure that the printed parts have sufficient resistance, thus minimizing the risk of deformation or breakage. During actual use, components may encounter impacts from different directions and with different intensities. In such cases, materials with high toughness can withstand deformation without cracking, thus achieving superior overall performance. As shown in Table 3, the addition of compatibilizer slightly decreases the strength and stiffness of the composites, while significantly improving the toughness. Compared with NH2-ESO, the shorter alkane chain length and higher reactivity of NH2-NC514 enable the composites to achieve a balance between strength and stiffness, which is mainly reflected in the effective coverage of the BFs surface during the processing and the entanglement with the molecular chains of the PLA matrix.

[0136] Test Example 5

[0137] Rheological property test

[0138] Test method: The rheological properties of the samples were measured on an Anton Paar MCR-502. The temperature was 210 °C, and 40 points were selected in the range of 0.01 - 100 rad / s.

[0139] Test results: The test results are as Figure 11 shown.

[0140] Figure 11 Rheological property test curves of 3D printed composites prepared for Application Examples 1 - 2 and Comparative Application Examples 1 - 3 (BF in the figure has the same meaning as BFs), where (a) is the complex viscosity and (b) is the storage modulus. As Figure 11 can be seen, the melt rheological characteristics of the composites are directly related to the dispersion degree of the fibers in the polymer matrix and the level of interfacial interaction between the fibers and the polymer. The complex viscosity of the PLA / BFs composites without adding compatibilizer is lower than that of the composites with added compatibilizer. This is because the compatibilizer can improve the interfacial compatibility of the composites and increase the entanglement degree with PLA. The change trend of the storage modulus is basically the same as that of the complex viscosity. With the increase of the compatibilizer content, the complex viscosity and the storage modulus show an upward trend. This is because the interaction between the compatibilizer and the polymer matrix and bamboo fibers greatly hinders the migration of polymer chains and the entanglement degree of the compatibilizer molecular chains themselves increases with the increase of the content.

[0141] Test Example 6

[0142] Interface Compatibility Test

[0143] Test method: The impact fracture surface and the changes in the surface microstructure of the impact spline in Test Example 4 were observed using a scanning electron microscope (SEM), and the observation was carried out on a TESCAN VEGA 11 with an accelerating voltage of 10 kV. In order to comprehensively evaluate the interfacial bonding strength of the 3D printed composite material and the dispersion of the compatibilizer in the 3D printed composite material, the 3D printed composite material specimen (impact spline) was soaked in toluene for three days after impact fracture, and then the changes in the impact fracture surface and the surface microstructure were observed by SEM.

[0144] Test results: The test results are as Figure 12 shown.

[0145] Figure 12 SEM images of the surface and fracture surface after impact fracture of the impact splines prepared from the 3D printed composite materials in Application Examples 1-2 and Comparative Application Examples 1-3 (the meaning of BF in the figure is the same as that of BFs), where (a)-(e) are the cross-section SEM images of PLA / BFs, PLA / BFs / 4NH2-ESO, PLA / BFs / 8NH2-ESO, PLA / BFs / 4NH2-NC514, and PLA / BFs / 8NH2-NC514 respectively, and (a’)-(e’) are the surface SEM images of PLA / BFs, PLA / BFs / 4NH2-ESO, PLA / BFs / 8NH2-ESO, PLA / BFs / 4NH2-NC514, and PLA / BFs / 8NH2-NC514 respectively. It can be Figure 12 seen that for the 3D printed composite material (PLA / BFs) without adding compatibilizer modification, a large number of deep grooves were generated during the fiber pull-out process, indicating that the interfacial adhesion between BFs and PLA was weak. After adding the compatibilizer, an indistinguishable fiber-matrix interface appeared on the impact fracture surface, confirming that the compatibilizer improved the interfacial bonding of the composite material. In contrast, the surface of the sample modified with NH2-NC514 remained relatively smooth after soaking, without obvious cracks. The SEM analysis of PLA / BFs / NH2-ESO after soaking showed that there were a large number of fine pores in the matrix, which was caused by the leaching of NH2-ESO. While there were fewer voids in the matrix of PLA / BFs / NH2-NC514, and there was no obvious gap at the interface between PLA and BFs, which indicated that PLA / BFs / NH2-NC514 showed enhanced reactivity, and the NH2-NC514 in it formed chemical bonds with the matrix and the BF surface, maintaining stability even under long-term solvent exposure, which was consistent with the mechanical property results discussed above.

[0146] Test Example 7

[0147] Processability and Appearance Quality Test

[0148] The 3D printing composites in Application Example 1 and Comparative Application Example 1 were respectively crushed by a crusher to obtain pellets. Subsequently, the pellets were fed into a single-screw extruder to form a thermoplastic filament with a diameter controlled at 1.75 ± 0.03 mm, and the temperature range of the single-screw extruder was set between 175 - 180 °C.

[0149] Figure 13 Figure for comparing the thermoplastic filaments prepared from the 3D printing composites in Application Example 1 and Comparative Application Example 1. Among them, the left is Application Example 1 and the right is Comparative Application Example 1. It can be seen from Figure 13 that the thermoplastic filament prepared from the 3D printing composite in Application Example 1 is smooth and has a uniform diameter (left side), while the surface of the thermoplastic filament prepared from the 3D printing composite in Comparative Application Example 1 is uneven (right side), and 3D printing cannot be achieved, and there will be a phenomenon of nozzle blockage.

[0150] The thermoplastic filament prepared from the 3D printing composite in Application Example 1 was used to produce a 3D printed product with an FDM printer. During the FDM printing process, the thermoplastic filament turned into a viscous flow state and was extruded layer by layer from the nozzle onto the support platform. The parameters of the FDM printer were set as: nozzle temperature 210 °C, platform temperature 80 °C, printing speed 40 mm / s, layer thickness 0.1 mm, and a 3D printed product was obtained. The printing process and the figure of the printed product are as shown in Figure 14 shown. The schematic diagram of extruding the thermoplastic filament by a single-screw extruder and then performing 3D printing is as shown in Figure 16 shown.

[0151] Figure 14 Figure for the printing process and the product when the thermoplastic filament prepared from the 3D printing composite in Application Example 1 was 3D printed. Among them, (a) is the printing progress of 20%, (b) is the printing progress of 40%, (c) is the printing progress of 60%, (d) is the printing progress of 80%, (e) is the printing progress of 100%, and (f)-(g) are the figures of the product. Figure 14 Shows the 3D printing process and the product of PLA / BFs / 4NH2-NC514, indicating that the PLA / BFs / 4NH2-NC514 bio-based composite material can not only produce simple solid structures, but also produce complex thin-walled hollow structures without the need for support structures and platform attachments. The printing process is smooth and the appearance of the model is good.

[0152] Figure 15For the comparison of the heat resistance of the sheet prepared from the 3D printing composite material PLA / BFs / 4NH2-NC514 in Application Example 1 and the PLA sheet (a thin square sheet sample with a side length of 10 mm and a thickness of 4 mm was prepared by 3D printing), from Figure 15 It can be seen that after heating the pure PLA sheet at 80 °C for 30 min, irreversible deformation occurred in the sheet (edge area). In contrast, under the same conditions, the sheet prepared from PLA / BFs / 4NH2-NC514 did not show obvious thermal deformation, indicating an enhanced durability against thermal deformation. And after testing, compared with pure PLA, the density of PLA / BFs / 4NH2-NC514 (decreased from 1.31 g / cm 3 to 1.28 g / cm 3 ) and the water absorption rate (decreased from 1.1% to 0.65%) both decreased, which indicates that the durability of PLA / BFs / 4NH2-NC514 is better than that of PLA. Coupled with the additional benefit of reducing raw material consumption, it can be used to manufacture products of the same volume.

[0153] The determination of the water absorption rate refers to GB / T 1034-2008. The sample was dried in an oven at 50 °C for 24 h, cooled to room temperature in a desiccator, and weighed (mass m1). The sample was immersed in distilled water at 23 °C for 25 h, then taken out, the water stains on the surface were wiped off, and weighed again (mass m2). The water absorption rate (C) of the sample can be expressed as:

[0154]

[0155] The determination of the density refers to GB / T 1033.1-2008. The sample suspended with a metal wire was weighed in air, and the sample suspended with the metal wire was immersed in a beaker filled with distilled water on a fixed bracket, and the sample was weighed in distilled water. The density (ρ S ) of the sample can be expressed as:

[0156]

[0157] Among them, ρ S is the density of the sample, m S，A is the mass of the sample in air, m S，IL is the apparent mass of the sample, and ρ IL is the density of distilled water.

[0158] The embodiments described above are only for describing the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An amino-functionalized epoxy cardanol glycidyl ether, characterized in that, The structural formula is as follows: Among them, represents -(CH2)6-.

2. A preparation method of the amino-functionalized epoxy cardanol glycidyl ether as described in claim 1, characterized in that, It includes the following steps: Hydrolyze KH550 to obtain hydrolyzed KH550; Use a cationic initiator to initiate the self-polymerization of epoxy cardanol glycidyl ether (NC514) to obtain poly-NC514; Use the poly-NC514 and the hydrolyzed KH550 as reactants to carry out a grafting reaction to obtain the amino-functionalized epoxy cardanol glycidyl ether.

3. The preparation method according to claim 2, characterized in that, The step of hydrolyzing KH550 includes: dissolving KH550 in an ethanol solution, magnetically stirring for 30 - 90 min to complete the hydrolysis reaction to obtain the hydrolyzed KH550; The dissolution concentration of KH550 in the ethanol solution is 2 wt.%.

4. The preparation method according to claim 2, wherein The step of using a cationic initiator to initiate the self-polymerization of NC514 includes: Dissolve the cationic initiator and NC514 in a solvent, vigorously stir at room temperature for 5 - 10 min to initiate the self-polymerization of NC514 to obtain the poly-NC514; The cationic initiator is BF3NH2Et; The dosage of the cationic initiator is 1 - 2 wt.% of the dosage of NC514.

5. The preparation method according to claim 2, characterized in that, The step of using the poly-NC514 and the hydrolyzed KH550 as reactants to carry out a grafting reaction includes: dissolving the poly-NC514 in the hydrolyzed KH550, stirring for 30 - 60 min to complete the grafting reaction to obtain the amino-functionalized epoxy cardanol glycidyl ether; The mass ratio of the poly-NC514 to the hydrolyzed KH550 is 3 - 1:1 - 3.

6. Application of the amino-functionalized epoxy cardanol glycidyl ether as claimed in claim 1 as a compatibilizer in the preparation of 3D printing composites.

7. A 3D printing composite material, characterized in that, By mass, the raw materials include: 70 parts of PLA, 30 parts of bamboo fiber (BFs), and 2 - 8 parts of compatibilizer; the compatibilizer is the amino-functionalized epoxy cardanol glycidyl ether as claimed in claim 1.

8. A method for preparing a 3D printed composite material as claimed in claim 7, characterized in that, It includes the following steps: First mix PLA, BFs, and the compatibilizer at room temperature, and then carry out melt mixing to obtain the 3D printing composite.

9. A method for preparing a 3D printed product using the 3D printed composite material according to claim 7, characterized in that, It includes the following steps: Crush the 3D printing composite and then melt extrude it to obtain a thermoplastic filament; carry out 3D printing on the thermoplastic filament to obtain a 3D printing product.

10. A 3D printing product prepared by the method as claimed in claim 9.

Images