DIW printing wood ink with room-temperature phosphorescence performance as well as preparation method and application of DIW printing wood ink

Abstract

The invention provides DIW printing wood ink with room-temperature phosphorescence performance as well as a preparation method and application of the DIW printing wood ink. The DIW printing wood ink provided by the invention comprises modified wood powder and water. The DIW printing wood ink disclosed by the invention has room-temperature phosphorescence performance, adopts a full bio-based material, can reduce dependence on limited fossil resources and reduce carbon emission, and meets the requirements of sustainable development, and in addition, the preparation method is simple and the cost is saved.

Description

Technical Field

[0001] The invention relates to a DIW printing wood ink with room temperature phosphorescence performance, a preparation method and an application thereof. Background Art

[0002] Direct Ink Writing (DIW) is an advanced additive manufacturing process that integrates materials science, fluid dynamics, and mechanical control. DIW utilizes an on-demand extrusion and direct deposition process to freely form complex three-dimensional structures using inks with controllable fluidity.

[0003] DIW technology uses viscoelastic fluids as printing materials. These materials exhibit semi-solid properties in static conditions, transform into pseudo-plastic fluids when subjected to force, and regain self-supporting properties after extrusion. To achieve smooth extrusion without discreteness or collapse, the printer is equipped with a closed-loop pressure feedback system that responds to nozzle pressure fluctuations within 0.25 milliseconds, ensuring layer thickness accuracy of 5 microns.

[0004] DIW printing materials mainly include the following categories: 1. Ceramic materials: DIW technology can use a high-viscosity ceramic slurry made by mixing ceramic powder and adhesive as raw material. This material is suitable for making high-strength and high-temperature resistant ceramic parts, such as bioceramics and high-performance ceramic functional parts; 2. Hydrogel: DIW technology is particularly suitable for hydrogel printing. Hydrogel is a material with high water absorption and elasticity. It can be precisely deposited layer by layer through DIW technology and is suitable for the manufacture of complex structures in biomedical applications; 3. Biomaterials: DIW technology is also commonly used in bioprinting, especially soft materials and biomaterials. This technology can achieve multi-material and high-throughput printing, and is suitable for the fields of tissue engineering and regenerative medicine.

[0005] Room temperature phosphorescence (RTP) has broad application prospects in many fields such as chemical / biological sensing, bioimaging, advanced optical anti-counterfeiting and information encryption due to its long luminescence lifetime and strong environmental sensitivity.

[0006] Most formulations developed for DIW printing require complex synthesis schemes, and there are few fully bio-based and readily available materials for additive manufacturing. Some DIW-printed RTP materials require the addition of chromophores to achieve luminescence effects. Summary of the Invention

[0007] In order to solve one of the above technical problems existing in the prior art, the present invention provides a DIW printing wood ink with room temperature phosphorescence performance, and a preparation method and application thereof.

[0008] The technical solution adopted by the present invention is as follows: a DIW printing wood ink with room temperature phosphorescence performance, which includes modified wood powder and water.

[0009] According to some embodiments of the present invention, the mass ratio of the modified wood flour to water is 100:(70-80), for example, 100, 70, 72, 75, 78, 80, etc.

[0010] According to some embodiments of the present invention, the mass ratio of the modified wood flour to water is 100:75.

[0011] According to some embodiments of the present invention, the modified wood flour comprises carboxymethyl cellulose.

[0012] According to some embodiments of the present invention, the degree of substitution of the modified wood flour is ≥0.4, for example, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.8, etc.

[0013] According to some embodiments of the present invention, the degree of substitution of the modified wood flour is ≥0.5.

[0014] According to some embodiments of the present invention, the degree of substitution of the modified wood flour is 0.5-0.8.

[0015] According to some embodiments of the present invention, the degree of substitution of the modified wood flour is 0.5-0.6.

[0016] The modified wood powder is prepared by a method comprising the following steps: first alkalizing the wood powder and then performing an etherification reaction with monochloroacetic acid.

[0017] In some embodiments of the present invention, the mesh size of the wood flour is 60 mesh, 80 mesh or 100 mesh.

[0018] In some embodiments of the present invention, the wood powder can be basswood powder, pine powder, fir powder, birch powder, oak powder or maple powder.

[0019] According to some embodiments of the present invention, the alkalization temperature is 15-65°C, for example, 15°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, etc.

[0020] According to some preferred embodiments of the present invention, the alkalization temperature is 30-40° C. In a most preferred embodiment, the alkalization temperature is 35° C.

[0021] According to some embodiments of the present invention, the alkalization time is 20 min-120 min, for example, 20 min, 30 min, 40 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, 100 min, 110 min, 120 min, etc.

[0022] According to some preferred embodiments of the present invention, the alkalization time is 50 min-90 min. According to some preferred embodiments of the present invention, the alkalization time is 55 min-85 min. According to a preferred embodiment of the present invention, the alkalization time is 60 min-70 min. According to a most preferred embodiment of the present invention, the alkalization time is 60 min-65 min.

[0023] According to some embodiments of the present invention, the etherification temperature is 40-90°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.

[0024] According to some embodiments of the present invention, the etherification temperature is 75-85°C. According to some preferred embodiments of the present invention, the etherification temperature is 78-85°C. According to the most preferred embodiment of the present invention, the etherification temperature is 80-82°C.

[0025] According to some embodiments of the present invention, the etherification time is 30 min-180 min, for example, 30 min, 40 min, 50 min, 60 min, 70 min, 75 min, 80 min, 85 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, 180 min, etc.

[0026] According to some embodiments of the present invention, the etherification time is 80 min to 180 min. According to some embodiments of the present invention, the etherification time is 85 min to 150 min. According to some embodiments of the present invention, the etherification time is 85 min to 120 min.

[0027] According to some embodiments of the present invention, the alkalization temperature is 35° C., the alkalization time is 60 min, the etherification temperature is 80° C., and the etherification time is 90 min.

[0028] According to some embodiments of the present invention, the mass ratio of wood flour to alkali is 1:0.8-1.4, preferably 1:1.2.

[0029] According to some embodiments of the invention, the base is sodium hydroxide.

[0030] In some embodiments of the present invention, the modified wood flour has a mesh size of 60 mesh, 80 mesh or 100 mesh.

[0031] According to some embodiments, the modified wood powder is prepared by a method comprising the following steps: adding the wood powder to an ethanol-water solution containing a portion (which may be 2 / 3 of the total alkali amount) of alkali (the mass ratio of this portion of alkali to wood powder may be 4:5), stirring at 30-40°C for 55-65 minutes, raising the reaction temperature to 65-75°C, and adding an ethanol-water solution containing chloroacetic acid; after stirring for 30-40 minutes, raising the reaction temperature to 75-85°C, adding an ethanol-water solution containing another portion (which may be 2 / 3 of the total alkali amount) of alkali (the mass ratio of this portion of alkali to wood powder may be 2:5); reacting at 75-85°C for 80-100 minutes, separating the obtained reaction mixture into solid and liquid, and washing and drying the obtained solid.

[0032] According to some embodiments, the modified wood powder is prepared by a method comprising the following steps: adding the wood powder to an ethanol-water solution of NaOH, stirring at 35° C. for 60 minutes, raising the reaction temperature to 70° C., and adding an ethanol-water solution containing chloroacetic acid; after stirring for 30 minutes, raising the reaction temperature to 80° C., and adding an ethanol-water solution containing NaOH; reacting at 80° C. for 90 minutes, separating the obtained reaction mixture into solid and liquid, and washing and drying the obtained solid.

[0033] The present invention also provides a method for preparing the DIW printing wood ink, which comprises mechanically mixing the modified wood powder with water to obtain the printing ink.

[0034] In some embodiments, the temperature of the mechanical mixing is 20-30°C.

[0035] The present invention also provides application of the DIW printing wood ink in DIW printing.

[0036] The present invention has the following advantages:

[0037] 1. Environmental performance: Compared with traditional petrochemical-based materials, all-biobased materials can reduce dependence on limited fossil resources, reduce carbon emissions, and meet the requirements of sustainable development.

[0038] 2. Low price: The present invention uses wood as raw material, and can obtain printable materials in large quantities through simple modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The degree of substitution results for the products of Examples 1-6 are shown.

[0040] Figure 2 The phosphorescence intensity and lifetime results of the products of Examples 1-6 are shown.

[0041] Figure 3The degree of substitution results for the products of Examples 7-11 are shown.

[0042] Figure 4 The phosphorescence intensity and lifetime results of the products of Examples 7-11 are shown.

[0043] Figure 5 The degree of substitution results for the products of Examples 12-16 are shown.

[0044] Figure 6 The phosphorescence intensity and lifetime results for the products of Examples 12-16 are shown.

[0045] Figure 7 The degree of substitution results for the products of Examples 17-21 are shown.

[0046] Figure 8 The phosphorescence intensity and lifetime results for the products of Examples 17-21 are shown.

[0047] Figure 9 The phosphorescence intensity and lifetime results for the products of Examples 22-26 are shown.

[0048] Figure 10 The results of the phosphorescence intensity and phosphorescence lifetime tests of CX-Wood prepared in Example 1 and commercially available CMC are shown.

[0049] Figure 11 2. The rheological curves of CX-Wood ink at different water contents in Examples 27-30.

[0050] Figure 12 The rheological curves of CX-Wood with different mesh sizes in Example 31 at a moisture content of 75%.

[0051] Figure 13 This is a schematic diagram of the printing process in Example 32.

[0052] Figure 14 The printing results of Example 32 are shown.

[0053] Figure 15 The mechanical properties of the printed samples of Example 32 are shown. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the following examples. The specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention in any way. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion about the concepts of the present disclosure. Such structures and technologies are also described in many publications.

[0055] Example 1 Preparation of raw material CX-Wood

[0056] Basswood powder (5 g, 60 mesh) was added to a 100 mL, 85% ethanol-water solution (4 g) of NaOH and stirred at 35°C for 60 min. The reaction temperature was then raised to 70°C, and 25 mL of an 85% ethanol-water solution containing 7 g of chloroacetic acid was added. After stirring for 30 min, the reaction temperature was raised to 80°C, and 25 mL of an 85% ethanol-water solution (containing 2 g of NaOH) was added. The reaction was continued at 80°C for 90 min. The resulting reaction mixture was filtered through a glass filter, washed twice with an 85% ethanol-water solution, and then twice with anhydrous ethanol. The solid product was dried at 80°C for 4 h to obtain CX-Wood.

[0057] Examples 2-6

[0058] The results are basically the same as Example 1, except that the alkalization time is 20 min, 40 min, 80 min, 100 min and 120 min respectively.

[0059] The substitution degree of the products of Examples 1-6 is shown in Table 1 and Figure 1 As shown, the phosphorescence intensity and phosphorescence lifetime are as follows Figure 2 As shown in the figure, with the increase of alkalization time, the degree of substitution of CX-Wood tends to increase first and then slightly decrease. When the alkalization time reaches 60 minutes, the degree of substitution, phosphorescence intensity and phosphorescence lifetime of the product reach the maximum value.

[0060] Table 1 Degree of substitution of products of Examples 1-6

[0061] Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Degree of substitution DS 0.5760 0.3319 0.4032 0.5199 0.4859 0.4510 Alkalization time 60min 20min 40min 80 minutes 100min 120 minutes

[0062] Examples 7-11

[0063] The method is basically the same as Example 1, except that the alkalization temperatures are 15°C, 25°C, 45°C, 55°C, and 65°C, respectively.

[0064] The substitution degree of the products of Examples 7-11 is shown in Table 2, and the phosphorescence intensity and phosphorescence life are shown in Table 2. Figure 3 and Figure 4 As shown in the figure, with the increase of alkalization temperature, the substitution degree of CX-Wood first increases and then decreases; when the alkalization temperature is 35℃, the substitution degree, phosphorescence intensity and phosphorescence lifetime of the product are the largest.

[0065] Table 2 Degree of substitution of products of Example 1 and 7-11

[0066] Example Example 1 Example 7 Example 8 Example 9 Example 10 Example 11 Degree of substitution DS 0.5760 0.4083 0.4232 0.4721 0.4296 0.3796 Alkalinization temperature 35℃ 15℃ 25℃ 45℃ 55℃ 65℃

[0067] Examples 12-16

[0068] The methods are basically the same as those in Example 1, except that the etherification times are 30 min, 60 min, 120 min, 150 min, and 180 min, respectively.

[0069] The substitution degree of the products of Examples 12-16 is shown in Table 3, and the phosphorescence intensity and phosphorescence life are shown in Table 3. Figure 5 、 6 shown.

[0070] The etherification time has a great influence on the substitution degree of CX-Wood. With the increase of etherification time, the substitution degree of CX-Wood shows a trend of first increasing and then decreasing. When the etherification time is 90 minutes, the product substitution degree, phosphorescence intensity and phosphorescence lifetime are the largest.

[0071] Table 3 Degree of substitution of products of Examples 1, 12-16

[0072] Example Example 1 Example 12 Example 13 Example 14 Example 15 Example 16 Degree of substitution DS 0.5760 0.3322 0.4425 0.5681 0.5453 0.5242 Etherification time 90 minutes 30min 60min 120 minutes 150min 180 minutes

[0073] Examples 17-21

[0074] The process is basically the same as Example 1, except that the etherification temperatures are adjusted to 40°C, 50°C, 60°C, 70°C, and 90°C, respectively.

[0075] The substitution degree of the products of Examples 1 and 17-21 is shown in Table 4, and the phosphorescence intensity and lifespan are shown in Table 4. Figure 7 、 8 shown.

[0076] The etherification temperature has a significant impact on the degree of substitution of the product. As the etherification temperature increases, the degree of substitution of the product increases first and then decreases. When the etherification temperature reaches 80℃, the degree of substitution, phosphorescence intensity, and phosphorescence lifetime of the product reach their maximum.

[0077] Table 4

[0078] Example Example 1 Example 17 Example 18 Example 19 Example 20 Example 21 Degree of substitution DS 0.5760 0.3663 0.3690 0.3812 0.4744 0.4653 Etherification temperature 80℃ 40℃ 50℃ 60℃ 70℃ 90℃

[0079] In summary, the optimal process reaction conditions for preparing CX-Wood are determined to be: alkalization temperature 30-40℃, alkalization time 55-65min, etherification temperature 75-85℃, etherification time 85-120min; the optimal process reaction conditions are: alkalization temperature 35℃, alkalization time 60min, etherification temperature 80℃, and etherification time 90min.

[0080] Examples 22-26

[0081] The method is basically the same as Example 1, except that the amount of alkali is adjusted. The total amount of alkali added is shown in Table 5.

[0082] Determine the optimal process parameters, add different amounts of alkali, the same as in Example 1, add in two parts, the first amount of alkali is two-thirds of the total amount of alkali, the second time the remaining one-third of the alkali, the effect of different alkali amounts on the degree of substitution is shown in Table 1, the effect of different degrees of substitution on phosphorescence intensity and phosphorescence life is shown in Table 1 Figure 9 .

[0083] Table 5

[0084] Example Example 22 Example 23 Example 24 Example 1 Example 25 Example 26 Amount of alkali 1.5g 3g 4.5g 6g 9g 10.5g First alkali addition amount 1g 2g 3g 4g 6g 7g Second alkali addition 0.5g 1g 1.5g 2g 3g 3.5g Degree of substitution DS 0.0664 0.1009 0.3288 0.5760 0.4129 0.3774

[0085] Comparison of CX-Wood prepared by the present invention and carboxymethyl cellulose CMC (commercially available)

[0086] The phosphorescence intensity and phosphorescence life of CX-Wood prepared in Example 1 and commercial CMC were tested. The phosphorescence intensity and life of CX-Wood were better than those of CMC. Figure 10 shown.

[0087] Example 27 Preparation of CX-Wood Ink

[0088] CX-Wood (100 g) prepared according to Example 1 was added to deionized water (55 mL) and the mixture was mechanically stirred at room temperature for 30 minutes to obtain CX-Wood ink.

[0089] Examples 28-30 Preparation of CX-Wood Ink

[0090] The process is basically the same as Example 1, except that the amount of deionized water is adjusted to 65 mL, 75 mL, and 85 mL, respectively.

[0091] The rheological properties of the CX-Wood ink obtained by adding different amounts of deionized water were tested. Figure 11 The rheological curves of CX-Wood ink at different water contents are shown in Figure 5. 55% represents the CX-Wood ink prepared in Example 27 (the mass ratio of CX-Wood to deionized water is 100:55), 65% represents the CX-Wood ink prepared in Example 28 (the mass ratio of CX-Wood to deionized water is 100:65), 75% represents the CX-Wood ink prepared in Example 29 (the mass ratio of CX-Wood to deionized water is 100:75), and 85% represents the CX-Wood ink prepared in Example 30 (the mass ratio of CX-Wood to deionized water is 100:85).

[0092] like Figure 11As shown in the figure, the viscosity of CX-Wood ink gradually decreases with increasing water content (from 55% to 85%). Subsequently, the viscoelastic properties of CX-Wood were analyzed by amplitude sweep, and the viscoelastic behavior was expressed as storage modulus (G') and loss modulus (G"). When the water content was 75% and 85%, G' and G" had an intersection, and the modulus at 75% water content (G'=G") was higher than that at 85% water content. This is because at this water content, the hydrogen bonds in the CX-Wood matrix form a dense polymer network, which easily recovers to a solid state with strong elasticity after extrusion.

[0093] Therefore, the optimal water content of CX-Wood ink is 75%-80% (i.e. the mass ratio of CX-Wood to water is 100:(75-80)), and the optimal water content is 75% (i.e. the mass ratio of CX-Wood to water is 100:75).

[0094] Example 31

[0095] The inventors also found that as the mesh size of CX-Wood increases (10 mesh, 20 mesh, 30 mesh, 40 mesh, 50 mesh, 60 mesh, 80 mesh, 100 mesh), the viscosity of CX-Wood ink gradually increases ( Figure 12 a). This is because as the mesh size increases, the reaction becomes more and more complete, and the entanglement of the polymer network of carboxymethyl groups connected by hydrogen bonds increases, resulting in an increase in viscosity. Subsequently, the viscoelastic properties of CX-Wood were analyzed by amplitude scanning ( Figure 12 b) Viscoelastic behavior is expressed as storage modulus (G') and loss modulus (G") when the mesh size of CX-Wood is too small, such as 10 or 20 mesh, G' and G" have no intersection, indicating that CX-Wood does not transform from a solid to a liquid state. This is because the reaction is not sufficient due to the small mesh size, resulting in larger wood powder particles. Figure 12 Figure c shows the relationship between the storage modulus (G') and the intersection point (G' = G") under shear strain and the CX-Wood mesh size. The figure shows that the modulus at (G' = G") decreases with increasing CX-Wood mesh size, indicating that CX-Wood ink transitions more easily from solid to liquid as the mesh size increases.

[0096] Example 32

[0097] The CX-Wood ink prepared in Example 29 (CX-Wood is the CX-Wood prepared in Example 1, and the mass ratio of CX-Wood to deionized water is 100:75) and the CMC ink prepared with commercial CMC (the mass ratio of commercial CMC to deionized water is 100:75) were 3D printed using a DIW device under the same parameter conditions. Figure 13The printing device is an Eazao zeio 3D printer. Parameters: Print speed 10mm / s-40mm / s; layer thickness 0.4mm-1mm; nozzle diameter 0.16mm-3mm; build volume 150mm×150mm×240mm.

[0098] Print results such as Figure 14 As shown. Figure 14 As shown, samples printed with the CX-Wood ink of the present invention maintained their structural integrity, while samples printed with the CMC ink exhibited varying degrees of collapse (highlighted in red).

[0099] Performance testing of printing products

[0100] The samples were tested for mechanical properties, including tensile strength and compressive strength. Figure 15 shown.

[0101] Tensile and compressive strengths were measured using a UTM2203 universal testing machine. Sample dimensions for the tensile test were 75 mm × 10 mm × 2 mm, with a tensile speed of 20 mm / min. Sample dimensions for the compression test were 18 mm × 18 mm × 18 mm, with a pressure of 2000 N and a compression speed of 20 mm / min.

[0102] The DIW wood printing ink of the present invention adopts all-biobased materials, which can reduce dependence on limited fossil resources, reduce carbon emissions, and meet the requirements of sustainable development. In addition, the preparation method is simple and cost-effective.

[0103] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Any technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A DIW printing wood ink with room temperature phosphorescence performance, comprising modified wood powder and water.

2. The DIW printing wood ink according to claim 1, characterized in that, The mass ratio of the modified wood powder to water is 100:(70-80), and preferably the mass ratio of the modified wood powder to water is 100:

75.

3. The DIW printing wood ink according to claim 1, characterized in that The modified wood powder contains carboxymethyl cellulose; the degree of substitution of the modified wood powder is ≥0.4, preferably the degree of substitution of the modified wood powder is ≥0.5, preferably 0.5-0.

6.

4. The DIW printing wood ink according to claim 1, characterized in that The modified wood powder is prepared by a method comprising the following steps: first alkalizing the wood powder and then performing an etherification reaction with chloroacetic acid.

5. The DIW printing wood ink according to claim 4, characterized in that, The alkalization temperature is 30-40° C., and / or the alkalization time is 50-90 min, and / or the etherification temperature is 75-85° C., and / or the etherification time is 80-180 min.

6. The DIW printing wood ink according to claim 4, characterized in that, The alkalization temperature is 35°C, the alkalization time is 60 minutes, the etherification temperature is 80°C, and the etherification time is 90-150 minutes.

7. The DIW printing wood ink according to claim 6, characterized in that The mass ratio of wood flour to alkali is 1:0.8-1.4, preferably 1:1.

2.

8. A method for preparing the DIW wood printing ink according to any one of claims 1 to 7, comprising mechanically mixing modified wood powder with water to obtain the printing ink.

9. The method according to claim 8, characterized in that The temperature of the mechanical mixing is 20-30°C.

10. Use of the DIW printing wood ink according to any one of claims 1 to 7 in DIW printing.

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