CN115490980A - A 3D printing hydrogel ink with adjustable gelation rate - Google Patents

Abstract

The invention relates to 3D printing hydrogel ink with adjustable gel rate, and belongs to the technical field of polymer gel. The ink adopts a double-component form, wherein the component A mainly comprises an aqueous solution of organic siloxane containing Si-N, and the component B mainly comprises an acrylamide monomer or acrylic acid, a cross-linking agent, persulfate and water; alkali metal ions or alkaline earth metal ions are added to the A component and/or the B component. The invention provides a novel organic siloxane/persulfate redox system containing Si-N, wherein alkali metal ions or alkaline earth metal ions are added into the system to catalyze the redox reaction, so that the rapid curing and forming of hydrogel at room temperature are realized. The gel time of the system can be regulated and controlled by regulating the concentration of alkali metal ions or alkaline earth metal ions, and the method is simple to operate and controllable in gel time.

Description

A 3D printing hydrogel ink with adjustable gelation rate

technical field

The invention relates to a 3D printing hydrogel ink with adjustable gel rate, belonging to the technical field of polymer gel.

Background technique

Bio-3D printing technology is a high-resolution and high-precision rapid prototyping technology, which has attracted extensive attention as an emerging research direction. Bio-3D printing technology is diverse, among which micro-extrusion is a powerful method, the bio-ink in the barrel is extruded through the nozzle under pressure and stacked layer by layer on the platform. Therefore, there is a need for bioinks that can not only be extruded smoothly but also can be quickly set after deposition. Hydrogel is an ideal printable material for microextrusion.

The Chinese invention patent with the authorized notification number CN113292678B discloses a direct writing 3D printing ion-type conductive hydrogel, which contains polyvinyl alcohol, chitosan, acrylamide, photoinitiator, crosslinking agent and Water needs to be cured by ultraviolet light to cure the three-dimensional hydrogel, and the curing time cannot be adjusted, which limits the application of the hydrogel. The Chinese invention patent with the authorized notification number CN113308148B discloses a direct writing 3D printing double-network conductive hydrogel. The hydrogel ink contains polyvinyl alcohol, carbon nanotubes, sodium carboxymethyl cellulose and water. Physical cross-linking and solidification will occur through cyclic freezing and thawing, and then chemical cross-linking will occur through immersion in hydrochloric acid solution, which is complicated to operate.

Contents of the invention

The purpose of the present invention is to provide a 3D printing hydrogel ink with adjustable gel rate, which mainly aims to solve the problems of uncontrollable 3D hydrogel gelation time and complicated operation in the prior art.

In order to achieve the above purpose, the technical scheme adopted by the 3D printing hydrogel ink with adjustable gel rate of the present invention is:

A 3D printing hydrogel ink with adjustable gel rate. The ink adopts a two-component form. The A component is mainly composed of an aqueous solution of Si-N-containing organosiloxane, and the B component is an acrylamide monomer. Or acrylic acid, crosslinking agent, persulfate and water; alkali metal ions or alkaline earth metal ions are added in A component and/or B component.

The Si-N-containing organosiloxane/persulfate redox system of the present invention can not only trigger the gelation of 3D printing hydrogel ink at room temperature, but also the Si-N-containing organosiloxane can undergo hydrolysis and crossover by itself. This improves the toughness of the 3D printed hydrogel.

Due to the addition of alkali metal ions or alkaline earth metal ions, rapid curing and molding of the hydrogel at room temperature is realized. In addition, the introduction of alkali metal ions or alkaline earth metal ions can also lower the freezing point of the hydrogel and improve the freezing resistance of the hydrogel.

Therefore, the hydrogel formed by the hydrogel ink of the present invention is an antifreeze hydrogel integrating high strength, high frost resistance and 3D printing.

Different from the redox system in the prior art to generate free radicals, the system in the present invention can adjust the gel time of the system by adjusting the concentration of alkali metal ions or alkaline earth metal ions. Therefore, the invention has simple operation and controllable gel time.

其中R为甲基或乙基。Preferably, the hydrogel uses Si-N-containing organosiloxane/persulfate as a redox initiation system for gelation, and by adding alkali metal ions or alkaline earth metal ions to the system and adjusting the amount added, the gel The glue speed is adjusted; the structure of the Si-N-containing organosiloxane is:

Wherein R is methyl or ethyl.

Preferably, the amount of the alkali metal ions or alkaline earth metal ions is 1-30wt% of the total water amount during gelling. The higher the mass percentage of alkali metal ions or alkaline earth metal ions, the faster the gelation speed of the hydrogel.

Preferably, the alkali metal ion is Na ⁺ or Li ⁺ ; the alkaline earth metal ion is Ca ²⁺ .

Preferably, the added amount of the Si-N-containing organosiloxane is 3-7% of the total water consumption when gelling. Wherein, the total water consumption during gelation is the quality of water in the reaction system after A and B are mixed.

Preferably, the addition amount of the acrylamide monomer or acrylic acid is 20-40% of the total water consumption during gelation.

Preferably, the added amount of persulfate is 0.1-0.5% of the total water consumption during gelation.

Preferably, the added amount of the cross-linking agent is 0.005-0.015% of the total water consumption during gelation. The addition of chemical cross-linking agents can further improve the strength of the hydrogel. Further preferably, the crosslinking agent is an N,N'-methylenebisacrylamide crosslinking agent.

Preferably, the A component and the B component are uniformly mixed according to a volume ratio of 1:1.

Description of drawings

Fig. 1 is the reaction mechanism of the speculated alkali metal ion doped composite hydrogel;

Figure 2 is 3D printing hydrogel ink, (a) precursor solution; (b) various shapes printed by 3D;

Fig. 3 is the gel time measurement figure of alkali metal ion or alkaline earth metal ion doping Si-N/PAAM hydrogel, (a) gel time changes with the concentration of alkali metal ion or alkaline earth metal ion; (b) hydraulic coagulation Different shapes printed out by glue;

Figure 4 is a diagram of the dynamic rheological behavior of Si-N/PAAM hydrogel doped with alkali metal ions or alkaline earth metal ions; (a) doping with different concentrations of Ca ²⁺ ; (b) doping with different concentrations of Na ⁺ ;

Fig. 5 is the DSC curve diagram of Ca2 ⁺ and Na ⁺ doped Si-N/PAAM hydrogel of different concentrations;

Figure 6 is the macroscopic mechanical behavior diagram of Ca ²⁺ doped Si-N/PAAM hydrogel after freezing at -20℃ for 24h; (a) is the photo of the hydrogel after twisting; (b) is the photo of the hydrogel after bending Photo; (c) is the press photo of the hydrogel after freezing.

detailed description

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

1. Specific examples of 3D printing hydrogel ink with adjustable gel rate

Example 1

The 3D printing hydrogel ink with adjustable gelation rate of this embodiment is prepared in the following manner:

(1) Preparation of Si-N-containing organosiloxane

Weigh 1,1,3,3-tetramethyldisiloxane and 3-aminopropyltrimethoxysilane with a molar ratio of 1:2 in a round bottom flask, add 3‰ Karst Platinum catalyst, stirred at room temperature for 3 hours until no bubbles were formed, and the organosiloxane product 1,1,3,3-tetramethyl-N1,N3-bis(3-(trimethoxysilyl)propyl)disiloxane-1,3-diamine was obtained (TB PDD).

The reaction equation is as follows:

In other embodiments, 3-aminopropyltrimethoxysilane can be replaced by 3-aminopropyltriethoxysilane, that is, the organosiloxane product can be 1,1,3,3-tetramethyl-N1,N3- bis(3-(triethoxysilyl)propyl)disiloxane-1,3-diamine (TBEPDD).

(2) Preparation of 3D printed hydrogel

The reaction mechanism of alkali metal ions or alkaline earth metal ions doped composite hydrogels is shown in Figure 1.

a. Take 10g of deionized water and place them in two beakers respectively;

b. Take one part and configure it as a 10wt% NaCl aqueous solution, add 1.25g of TBPDD, stir well until it is completely dissolved, and record it as component A of the precursor for 3D printing;

c. Take another part and add 0.025g of ammonium persulfate, 5.0g of acrylamide and 0.001g of N,N'-methylenebispropylene cross-linking agent, stir well and record it as component B;

d. Mix component A and component B uniformly according to the volume ratio of 1:1 to obtain printable ink, which gels quickly at room temperature.

After combining components A and B in step 2, the weight percentage of NaCl in the NaCl aqueous solution is 5wt%, and the following examples are all described based on the proportion after mixing.

The 3D printing hydrogel ink of the present application corresponds to the A and B components in the above step (2), as shown in FIG. 2 .

Example 2

The 3D printing hydrogel ink with adjustable gelation rate in this example is different from Example 1 in that in step (2), the weight percentage of NaCl in the NaCl aqueous solution is 15wt%.

Example 3

The 3D printing hydrogel ink with adjustable gelation rate in this embodiment differs from that in Embodiment 1 in that in step (2), the weight percentage of NaCl in the NaCl aqueous solution is 20 wt%.

Example 4

The 3D printing hydrogel ink with adjustable gelation rate in this embodiment differs from that in Embodiment 1 in that in step (2), the weight percentage of NaCl in the NaCl aqueous solution is 25 wt%.

Example 5

The 3D printing hydrogel ink with adjustable gelation rate in this example is different from Example 1 in that: in step (2), the weight percentage of NaCl in the NaCl aqueous solution is 30wt%.

Example 6-10

The 3D printing hydrogel ink with adjustable gel rate in this example differs from Examples 1-5 in that: in step (2), the NaCl aqueous solution is replaced by a CaCl ₂ aqueous solution.

In other implementation situations, the NaCl aqueous solution can also be replaced by a LiCl aqueous solution.

Example 11

The 3D printing hydrogel ink with adjustable gel rate in this example differs from Example 1 in that in step (2), 5.0 g of acrylic acid is used to replace acrylamide.

2. Comparison ratio

The 3D printing hydrogel ink with adjustable gel rate in this example differs from Example 1 in that: in step (2), no NaCl aqueous solution is added to component A.

3. Experimental example

Experimental Example 1 Gel Time Determination

In this experimental example, the gel time of Examples 1-10 was observed, and the results are shown in FIG. 3 .

It can be seen from Figure 3a that no matter Na ⁺ or Ca ²⁺ is added to the redox system, the gelation time will be shortened with the increase of ion concentration and the gelation of hydrogel will be accelerated, and at the same ion concentration, Ca ²⁺ promotes the gelation of hydrogels more than Na ⁺ .

In this experiment, different pigments were added to the obtained hydrogel and 3D printed. The result is shown in Figure 3b.

Experimental Example 2 Rheological Behavior Test

In this experimental example, the rheological behavior of the hydrogel precursors in Examples 1-10 was tested respectively. Using the American HAAKEMARSⅢ rheometer, 20PiL geometric parallel plates, the samples were dropped between the parallel plates at room temperature. Viscosity test, the frequency sweep is 1Hz, the results are shown in Figure 4.

Figure 4a is a graph showing the viscosity versus time of Ca2 ⁺ doped silicone/PAAM hydrogels at different concentrations (5wt%, 7.5wt%, 10wt%, 12.5wt%, 15wt%) during the gelation process. Taking the 15wt% Ca ²⁺ doped silicone/PAAM hydrogel solution as an example, the viscosity was below 1 Pa at the beginning, and when the time reached about 260s, the 15wt% Ca ²⁺ doped silicone/PAAM hydrogel solution The viscosity of the solution started to rise rapidly and then stabilized, which indicated that the polymerization reaction of the solution was very rapid. It can also be seen that the first turning point of the viscosity change gradually shifts to the left with the increase of Ca ²⁺ content, indicating that the higher the content of alkali metal ions, the earlier the polymerization reaction occurs. Therefore, Ca ²⁺ doped silicone/PAAM hydrogels can be used for 3D printing.

Figure 4b is a plot of the viscosity of Na ⁺ doped silicone/PAAM hydrogels as a function of time during the gelation process, the curve ^is similar to that of 4a, except that the gelation The gel time is shorter compared to that of Na ⁺ doped silicone/PAAM hydrogels.

Experimental Example 3 Frost Resistance Test

In this experimental example, low-temperature performance tests were performed on the hydrogels prepared in Examples 1, 3, 5 and Examples 6, 8, and 10, and the results are shown in Figure 5 .

The hydrogel was analyzed by using a Q100 differential scanning calorimeter (DSC) from TA Company of the United States. According to Figure 5a, it can be seen that with the increase of Ca ²⁺ concentration, the crystallization temperature of the hydrogel is continuously decreasing, and no ^Ca 2+ is present. The crystallization peak of the silicone/PAAM hydrogel water with ⁺ appeared at −18 °C, while the crystallization peak of the silicone/PAAM hydrogel containing 15 wt% Ca2 ⁺ appeared at −29 °C. The results of DSC showed that doping Ca ²⁺ in the silicone/PAAM hydrogel can help to lower the freezing point of the hydrogel and improve the antifreeze performance of the hydrogel.

According to Figure 5b, it can be seen that the crystallization peak of 15wt% Na ⁺ doped silicone/PAAM hydrogel appears at -29 °C, while the crystallization peak of 5wt% -Na ⁺ doped silicone/PAAM hydrogel appears at - Around 19°C. This shows that the hydrogel is not frozen at -20°C, and the freezing point of the hydrogel decreases with the increase of the concentration of alkali metal ions.

In this experimental example, the hydrogel prepared in Example 5 was frozen at -20° C. for 24 hours to perform a macroscopic mechanical test, and the results are shown in FIG. 6 .

It can be seen from Figures 6a and 6b that the hydrogel prepared by the present invention can still be twisted and bent after being frozen at -20°C for 24 hours, indicating that the hydrogel has excellent stretch resistance after freezing. Figure 6c: The hydrogel was prepared into a cylindrical test sample, and after being frozen, it was pressed by hand. After the pressing, the sample returned to its original shape, indicating that the hydrogel also has excellent resilience after freezing.

Claims (9)

1. The 3D printing hydrogel ink with adjustable gel rate is characterized in that the ink adopts a two-component form, wherein a component A mainly comprises an aqueous solution of organic siloxane containing Si-N, and a component B mainly comprises an acrylamide monomer or acrylic acid, a cross-linking agent, persulfate and water; alkali metal ions or alkaline earth metal ions are added to the A component and/or the B component.

2. The adjustable-gel-rate 3D printing hydrogel ink according to claim 1, wherein the hydrogel is gelled by using an organic siloxane/persulfate containing Si-N as a redox initiation system, and the gel speed is adjusted by adding alkali metal ions or alkaline earth metal ions into the system and adjusting the adding amount; the structure of the organic siloxane containing Si-N is as follows:

wherein R is methyl or ethyl.

3. The 3D printing hydrogel ink with adjustable gelation rate of claim 1, wherein the amount of the alkali metal ions or the alkaline earth metal ions is 1 to 30wt% of the total water amount in gelation.

4. The adjustable gel rate 3D printing hydrogel ink of claim 3, wherein the alkali metal ion is Na ⁺ Or Li ⁺ (ii) a The alkaline earth metal ion is Ca ²⁺ 。

5. The adjustable-gel-rate 3D printing hydrogel ink according to claim 1, wherein the addition amount of the organic siloxane containing Si-N is 3-7% of the total water amount in the gel.

6. The 3D printing hydrogel ink with the adjustable gel rate as claimed in claim 1, wherein the addition amount of the acrylamide monomer or acrylic acid is 20-40% of the total water consumption during gel.

7. The 3D printing hydrogel ink with the adjustable gel rate as claimed in claim 6, wherein the persulfate is added in an amount of 0.1-0.5% of the total water consumption in gelation.

8. The 3D printing hydrogel ink with adjustable gel rate according to claim 1, wherein the addition amount of the cross-linking agent is 0.005-0.015% of the total water consumption in the gel.

9. The adjustable gel rate 3D printing hydrogel ink according to any one of claims 1 to 8, wherein the a component and the B component are mixed in a volume ratio of 1:1, and uniformly mixing.

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