CN114957804A

CN114957804A - Preparation and application of green functional foam material for 3D printing

Info

Publication number: CN114957804A
Application number: CN202210652730.4A
Authority: CN
Inventors: 宋弋; 徐博; 卢舒瑜; 马涛; 户昕娜; 周宇星; 刘攀航
Original assignee: China Agricultural University
Current assignee: China Agricultural University
Priority date: 2022-06-08
Filing date: 2022-06-08
Publication date: 2022-08-30
Anticipated expiration: 2042-06-08
Also published as: CN114957804B

Abstract

The invention relates to a green functional foam material for 3D printing, which is prepared by the following steps: mixing a surfactant and water in a ratio of 1: (500-1200) (g/mL) to prepare a solution; mixing the nano-cellulose crystal with the obtained solution to prepare a hydrogel liquid, and stirring the obtained hydrogel liquid by using a stirrer to generate foam so as to construct a foam material system. The resulting foam was loaded into the barrel of a printing device and the extruded filamentary material was printed into a three-dimensional green functional foam. The raw materials of the foam material provided by the invention have biological safety, are green and pollution-free, and can be widely applied to the fields of biotechnology, material science, chemical engineering, food processing and the like to prepare three-dimensional cell culture scaffolds, prepare low-density aerogels, adsorb grease, load small molecular substances and produce novel foods.

Description

Preparation and application of green functional foam material for 3D printing

Technical Field

The invention belongs to the technical field of cellulose compositions, and particularly relates to preparation and application of a functional material for 3D printing.

Background

Foam is a common dispersion system for dispersing gas into liquid or semisolid, and can reduce the density of the system, increase the specific surface area and endow the product with unique physical properties. However, the stability of foam produced by only relying on a single surfactant is to be improved, and the foam is broken in a short time due to low viscosity of the liquid, which limits the range and the prospect of application of the foam material.

The 3D printing technology is also called additive manufacturing technology, is a processing mode of building a model based on computer aided design and building a three-dimensional object by stacking in a mode of adding materials layer by layer, can be used for building a complex structure which is difficult to realize by a traditional method, customizes raw material proportion and appearance according to requirements in a personalized mode, reduces waste of raw materials caused by the traditional manufacturing mode, and has wide application prospect. At present, a 3D printing system participated by the existing nano cellulose crystal is mainly gel, the gel needs higher nano cellulose crystal addition amount, the product density is higher, the cost is higher, the dispersion system is single, and the form of the 3D printing product is restricted.

Utilize 3D printing technique processing to handle high adsorptivity material, can customize the pore density degree and the specific surface area of adjusting the finished product, and then control adsorption efficiency. Compared with gel systems, foam systems have lower density and higher specific surface area, and aerogel materials prepared on the basis of the foam systems have better adsorption performance. The aerogel material used as the adsorbent should have stable mechanical properties and adsorption properties. The adsorption capacity of the polyimide aerogel material in the existing organic solvent adsorption material on organic pollutants and grease can reach 30-195 times of the self mass of the polyimide aerogel material, and the polyimide aerogel material also has considerable application prospect in the aspect of efficient separation of organic pollutants. The adsorption of grease is also used in the food field, and the application of the grease requires an adsorption material with higher biosafety.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a green functional foam material for 3D printing, and the foam material provided by the invention can be directly used as a 3D printing raw material without adding extra raw materials.

The invention also provides application of the green functional foam material.

The technical scheme for realizing the above purpose of the invention is as follows:

A3D printed green functional foam material prepared by the following steps:

(1) mixing a surfactant and water in a ratio of 1: (500-1200) (g/mL) to prepare a solution;

(2) mixing a nano-cellulose crystal with the solution obtained in the step (1) to prepare a hydrogel liquid, wherein the mass ratio of the nano-cellulose crystal to the solution is 1 (5-13.33);

(3) stirring the hydrogel liquid obtained in the step (2) by using a stirrer to generate foam, and constructing a foam material system.

(4) And (4) filling the foam material obtained in the step (3) into a charging barrel of a printing device, and printing the extruded filiform material into a three-dimensional green functional foam material.

The nano cellulose crystal is a rigid cellulose crystal with a nano scale, can be extracted from agricultural byproducts such as straws and the like, has the characteristics of greenness, pure nature, safety, no toxicity, good biocompatibility and good adsorption capacity, can enhance the foam stability due to high viscosity, and cannot independently stabilize a foam system due to strong hydrophilicity of surface sulfate groups. The composite action of the nano-cellulose crystal and the lauroyl arginine ethyl ester hydrochloride can obtain stable high-viscosity foam, and in addition, the lauroyl arginine ethyl ester hydrochloride can be combined with the cellulose nano-crystal through electrostatic action, the physical combination mode does not generate chemical reaction, the biological safety is high, and the hydrophobicity of the cellulose nano-crystal can be enhanced. By adjusting the appropriate adding proportion of the two, the produced foam system has appropriate extrusion characteristics and characteristics of maintaining self-form and can be used as a raw material for 3D printing.

Lauroyl arginine ethyl ester hydrochloride is a novel cationic surfactant, is different from the high toxicity of most other cationic surfactants, has high biological safety, is nontoxic and harmless to metabolites in mammals, and has generally accepted as safe (GRAS) certification by the U.S. food and drug administration.

Preferably, in step (1), the surfactant is lauroyl arginine ethyl ester hydrochloride, which is mixed with water in a ratio of 1: (900-1000) preparing a solution.

Preferably, in the step (2), the mass ratio of the nano-cellulose crystals to the solution is 1: (6.67-10); namely, the mass fraction of the nanocellulose crystal is 10 wt% to 15 wt%.

The preparation method of the hydrogel liquid comprises the following steps: slowly adding the nano cellulose crystal into the vortex under the stirring state, and keeping stirring for 0.5-2 h.

Wherein, in the step (3), the mixture is stirred for 2min at 11000rpm by a stirrer.

Further, in step (4), the printing parameters are:

the diameter of the nozzle is 0.34-0.51 mm, the printing height is 0.4-0.7 mm, the extrusion rate is 5-10 mm/s, and the extrusion pressure is 15-80 Pa.

A further preferred technical solution of the present invention is that the printing parameters are: the printing temperature is 20-28 ℃, the printing height is 0.6-0.7 mm, the extrusion rate is 6mm/s, the nozzle diameter is 0.34mm, and the extrusion pressure is 30-40 Pa.

The green functional foam material for 3D printing obtained by the preparation method can be used for grease adsorption, and has different grease adsorption functions under different printing interval gaps.

In the step (4), the printing gap parameter of the printing is adjusted to be 0.75-1.5 mm by setting the printing interval in the printing parameters or designing the printing model.

In the above method, the operation of directly adjusting the printing interval in the printing parameters is simpler. By adjusting the printing interval to be large, a lattice structure can be formed.

Further, the oil absorption capacity of the green functional foam material product is adjusted to be increased from 10g/g to 14g/g by adjusting the printed gap parameter to be changed from 0.75-1.5 mm.

Wherein, after printing is finished, the mixture is frozen and dried for 40 to 60 hours at the temperature of between 60 ℃ below zero and 70 ℃ below zero.

The green functional foam material is applied to grease adsorption.

The invention has the beneficial effects that:

the raw materials of the foam material provided by the invention have biological safety, are green and pollution-free, and can be widely applied to the fields of biotechnology, material science, chemical engineering, food processing and the like to prepare three-dimensional cell culture scaffolds, prepare low-density aerogels, adsorb grease, load small molecular substances and produce novel foods.

Compared with a gel system, the foam material provided by the invention can be applied to a 3D printing technology, so that the product density can be obviously reduced, and the pore volume rate can be improved; the rheological property of the product is improved, the concentration of the nano-cellulose crystal required for achieving the same printing effect is lower, and the cost is reduced; the specific surface area is increased, and more possibility is provided for loading functional substances with surface adsorption characteristics.

According to the invention, the relation that the viscosity of the foam system of different nano-cellulose crystals changes along with the change of the shearing rate under the condition of determining lauroyl arginine ethyl ester hydrochloride is determined, so that the addition of the nano-cellulose crystals can obviously improve the viscosity of the system and endow the system with printability which the system does not have; the examples and printing examples demonstrate that the foam under the provided conditions has good printing results; the ability of the material in grease adsorption is proved by printing foam grids at different intervals and adsorbing grease after freeze drying, the porosity and the adsorption ability of the material can be adjusted by utilizing a 3D printing technology, and the effect which cannot be achieved by other technical means is realized.

Drawings

FIG. 1 shows the relationship between the viscosity of the foam system and the shear rate, wherein the mass fraction of lauroyl arginine ethyl ester hydrochloride is 0.1 wt%, and the mass fractions of nano cellulose crystals are 0 wt%, 1 wt%, 5 wt%, 10 wt% and 15 wt%, respectively.

FIG. 2 is a top view and a front view of a 1cm X1 cm cube obtained by printing example 1 (wherein 2-A is a top view and 2-B is a front view).

FIG. 3 is a top view and a front view of a 1cm X1 cm cube obtained in printing example 2 (wherein 3-A is a top view and 3-B is a front view).

FIG. 4 is a top view and a front view of a 1cm by 1cm cube obtained by printing example 3 (where 4-A is a top view and 4-B is a front view).

FIG. 5 is a top view and a front view of a 1cm by 1cm cube obtained by printing example 4 (wherein 5-A is a top view and 5-B is a front view).

FIG. 6 is a top view of a 1cm by 1cm grid structure with different fill intervals obtained by 3D printing in application example 1 (where the 6-A print interval is 0.75mm, the 6-B print interval is 1.0mm, and the 6-C print interval is 1.5 mm).

Fig. 7 shows the results of the grease absorption performance test of the control group and different filling gap groups in application example 1.

FIG. 8 is a schematic diagram of printing with a printing interval of 0.75mm in application example 1;

fig. 9 is a schematic diagram of a grid structure printed in application example 1.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The diameter of the nano cellulose crystal is 1-100 nm, the length is within 300nm, and the nano cellulose crystal is produced by a cellulose sulfuric acid hydrolysis method.

Test example:

a method for preparing a nano cellulose based green functional foam material comprises the following steps:

(1) weighing 0.02g of lauroyl arginine ethyl ester hydrochloride, dissolving in 20mL of ultrapure water, and magnetically stirring for 5 min; the magnetic stirring is to mix the solution evenly by the rotation of the magnetons, and the rotation speed of the magnetons is not strictly required, and is about 1000rpm in the test example. The rotation speed can be in the range of 500 rpm-1500 rpm.

(2) Slowly adding nano-cellulose crystals with different masses into the vortex of the solution obtained in the step (1) under the stirring state to ensure that the mass fractions of the nano-cellulose crystals are respectively 0 wt%, 1 wt%, 5 wt%, 10 wt% and 15 wt%, and keeping magnetic stirring for 0.5 h;

(3) and (3) stirring the hydrogel liquid obtained in the step (2) for 2min at 11000rpm by using a stirrer to obtain foam. The stirrer used is equipped with stirring blades, the purpose of which is to generate foam.

By researching the performance of the foam obtained in the step (3), obviously, compared with a pure lauroyl arginine ethyl ester hydrochloride solution, the addition of the nano cellulose crystal can obviously improve the viscosity of the system, so that the system has printability. The viscosity of the resulting foam system was measured as a function of shear rate and the results are shown in FIG. 1. According to the detection result, the foams with the mass fractions of 0 wt%, 1 wt% and 5 wt% of the nanocellulose crystal are too thin to support the self structure and have no printing performance;

when the mass fraction of the nano-cellulose crystals reaches more than 20 wt%, the smooth extrusion and continuous filament discharge of foams cannot be realized due to the excessively high system viscosity, and the nano-cellulose crystals are difficult to apply to 3D printing.

Through the groping test, the prepared foam with the mass fraction of the nano cellulose crystal of 10-15 wt% is determined.

Example 1

A preparation method of a nanocellulose-based green functional foam material with good shape fidelity and biological safety for 3D printing comprises the following steps:

(1) weighing 0.02g of lauroyl arginine ethyl ester hydrochloride, dissolving in 20mL of ultrapure water, and magnetically stirring for 5 min;

(2) slowly adding 2g of nano-cellulose crystals into the vortex of the solution obtained in the step (1) under the stirring state, and keeping magnetic stirring for 0.5 h;

(3) and (3) stirring the hydrogel liquid obtained in the step (2) for 2min at a stirring speed of 11000rpm by using a stirrer to obtain foam.

Printing example 1

The foam material obtained in example 1 was loaded into a printing cartridge, the printing interval in the printing parameters was set to 0.75, a printing model was input in a 3D printer, and the printing parameters were set to: the printing temperature is 25 ℃, the printing height is 0.625mm, the extrusion rate is 9mm/s, the nozzle diameter is 0.34mm, and the extrusion air pressure is 30Pa, and the extruded filamentous material is printed into the three-dimensional green functional foam material.

The resulting 1cm by 1cm cube was printed with good shape fidelity, see fig. 2.

Example 2

(2) slowly adding 2.5g of nano-cellulose crystals into the vortex of the solution obtained in the step (1) under the stirring state, and magnetically stirring for 2 hours;

Printing example 2

The foam material obtained in example 2 was loaded into a printing cartridge, a printing model was input in a 3D printer, and the printing parameters were set as: the printing temperature is 25 ℃, the printing height is 0.5mm, the extrusion speed is 8mm/s, the nozzle diameter is 0.34mm, and the extrusion air pressure is 50Pa, and the extruded filamentous material is printed into the three-dimensional green functional foam material. The resulting material was printed as shown in fig. 3.

Example 3

(2) slowly adding 3g of nano-cellulose crystals into the vortex of the solution obtained in the step (1) under the stirring state, and magnetically stirring for 1 h;

(3) and (3) stirring the hydrogel liquid obtained in the step (2) for 1min at a stirring speed of 11000rpm by using a stirrer to obtain foam.

Printing example 3

The foam material obtained in example 3 was loaded into a printing cartridge, a printing model was input in a 3D printer, and the printing parameters were set as: the printing temperature is 25 ℃, the printing height is 0.4mm, the extrusion rate is 6mm/s, the nozzle diameter is 0.34mm, and the extrusion air pressure is 80Pa, and the extruded filamentous material is printed into the three-dimensional green functional foam material. The resulting material was printed as shown in fig. 4.

Example 4

(1) weighing 0.04g of lauroyl arginine ethyl ester hydrochloride, dissolving in 20mL of ultrapure water, and magnetically stirring for 5 min;

(2) slowly adding 2g of nano-cellulose crystals into the vortex of the solution obtained in the step (1) under the stirring state, and magnetically stirring for 0.5 h;

Printing example 4

The foam obtained in example 4 was loaded into a printing cylinder, a printing model was input in a 3D printer, and the printing parameters were set as: printing was started with the foam material at a printing temperature of 25 ℃, a printing height of 0.67mm, an extrusion rate of 8mm/s, a nozzle diameter of 0.51mm, and an extrusion pressure of 17 Pa. The resulting material was printed as shown in fig. 5.

Application example 1

The foam obtained in example 1 was loaded into a printing cylinder, a printing model was input in a 3D printer, and the printing parameters were set as: the printing temperature is 25 ℃, the printing height is 0.667mm, the extrusion rate is 6mm/s, the nozzle diameter is 0.34mm, the extrusion air pressure is 35Pa, the printing gaps are respectively adjusted to be 0.75mm, 1.0mm and 1.5mm, and the extruded filamentous material is printed into the three-dimensional green functional foam material. The structure can be regarded as a compact cube (see fig. 8) with no grid pores when the printing interval is set at 0.75mm and below, and by continuing to enlarge the printing interval, a grid structure with adjustable intervals can be formed (see fig. 9). Too large a gap can affect the printing effect and internal collapse occurs.

The printing result is shown in fig. 6 (fig. 6 shows the structure before freeze drying, and the appearance is not obviously changed after freeze drying), and the aerogel prepared after printing has loose pore diameter, good shape fidelity and biological safety, and can be applied to grease adsorption.

Taking unprinted foam as a control group, and freeze-drying the foam grid material obtained by printing and the foam of the control group under the conditions of: 60 ℃ below zero, 48 h.

And (3) soaking the green functional foam material subjected to freeze drying in corn oil for 2min, and measuring the grease adsorption mass per unit mass of foams at different filling intervals.

Fig. 7 shows the results of the grease absorption performance test of the control group and different filling gap groups in application example 1. Obviously, the filling interval is adjusted through the 3D printing technology, the porosity and the adsorption capacity of the material can be adjusted, and the higher filling interval can endow the material with higher porosity and adsorption capacity, which cannot be achieved through other technical means.

Although the present invention has been described in the foregoing by way of examples, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. A green functional foam material for 3D printing is characterized by being prepared through the following steps:

(3) stirring the hydrogel liquid obtained in the step (2) by using a stirrer to generate foam, and constructing a foam material system;

2. The 3D printed green functional foam according to claim 1, wherein in step (1), the surfactant is lauroyl arginine ethyl ester hydrochloride, which is mixed with water in a ratio of 1: (900-1000) preparing the solution.

3. The 3D printed green functional foam material according to claim 1, wherein in step (2), the mass ratio of the nanocellulose crystals to the solution is 1: (6.67-10); the preparation method of the hydrogel liquid comprises the following steps: slowly adding the nano cellulose crystal into the vortex under the stirring state, and keeping stirring for 0.5-2 h.

4. The 3D printed green functional foam according to claim 1, wherein in step (3), the mixture is stirred with a stirrer at 11000rpm for 2 min.

5. The 3D printed green functional foam material according to claim 1, wherein in step (4), the printing parameters are:

6. The 3D printed green functional foam material according to claim 4, wherein the printed parameters are: the printing temperature is 20-28 ℃, the printing height is 0.6-0.7 mm, the extrusion rate is 6mm/s, the nozzle diameter is 0.34mm, and the extrusion pressure is 30-40 Pa.

7. The 3D printed green functional foam material according to claim 1, wherein in the step (4), the printed gap parameter is adjusted to 0.75-1.5 mm by setting the printing interval in the printing parameters or by designing the printing model.

8. The 3D printed green functional foam according to claim 7, wherein the increase of oil absorption capacity of the resulting green functional foam product from 10g/g to 14g/g is controlled by adjusting the printed void parameter to vary from 0.75-1.5 mm.

9. The 3D printed green functional foam material according to claim 1, wherein after printing is completed, the foam material is freeze-dried at-60 to-70 ℃ for 40 to 60 hours.

10. Use of the green functional foam material of any one of claims 1 to 9 in grease absorption.