CN113897691A

CN113897691A - Preparation method of bead nanofiber with composite structure

Info

Publication number: CN113897691A
Application number: CN202111351486.XA
Authority: CN
Inventors: 杨垚瑶; 陈伟; 王梦龙; 余灯广
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2021-11-16
Filing date: 2021-11-16
Publication date: 2022-01-07

Abstract

The invention discloses a preparation method of bead-structured nano-fiber based on a multi-fluid electrostatic spinning process, which is characterized in that: a solvent having no spinnability is introduced as an interlayer fluid into a plurality of fluids participating in electrospinning. The method can simply and stably prepare the bead-string nanofibers, and the bead-string nanofibers can have a composite structure by regulating and controlling the components, the compositions, the relative sizes and the spatial distribution of the multiple fluids. The preparation method of the bead nanofiber with the composite structure through the one-step method effectively improves the stability of bead nanofiber preparation and expands the design and development of the bead nanofiber, so that the bead nanofiber can be applied to more fields.

Description

Preparation method of bead nanofiber with composite structure

Technical Field

The invention relates to the technical field of nano fibers, in particular to a preparation method of bead string nano fibers with a composite structure.

Background

Electrospinning is a method for preparing nanofibers, wherein beaded nanofibers are a special presence in electrospun nanofibers and are composed of nanoscale fibers and axially aligned micro-nanoscale beads. And the existence of the bead structure in the fiber can effectively improve certain special properties of the fiber. In order to further widen the application prospect of the bead nanofiber, the development of a method for stably preparing the bead nanofiber becomes more important.

The existing method for preparing the bead-string nano fiber has the following defects:

(1) the preparation method is complex, and the bead nanofibers are usually prepared by a multi-step method.

Such as chinese patent 201310638276.8; the document ACS EST Water 2021,1, 1577-1586; the Journal of Membrane Science 2020,615,118499.

(2) The preparation method has no general applicability.

For example: chinese patent 202010315708.1; chinese patent 201911258093.7; chinese patent 202110823272.1 and the like only change a single spinning parameter in the process of preparing the bead nanofiber by electrostatic spinning. However, the properties of the spinning solution, the technological parameters and the environmental parameters during electrostatic spinning and the like all affect the formation and the appearance of the bead nanofiber, so that the method for preparing the bead nanofiber by only changing a certain specific parameter is often not suitable for other systems;

(3) the unity of the structure. The existing research mainly focuses on the bead nanofiber prepared by single-fluid electrostatic spinning, the spatial distribution among all components cannot be regulated, and the development of the performance and the application of the bead nanofiber is greatly limited.

For example: chinese patent 201510738117.4 prepares beaded nanofibers with a single structure by determining the optimal content of polycaprolactone and polyethylene glycol in the mixed solution and electrostatic spinning conditions; chinese patent 201410133374.0 discloses a method for preparing PLA beaded nanofibers with a single structure under certain concentration and solvent ratio conditions.

Disclosure of Invention

The invention aims to solve the problems and provides a preparation method of bead nanofiber with a composite structure, which is characterized in that the method is carried out based on a multi-fluid electrostatic spinning process and comprises the following steps:

step A1, preparing spinning solution to obtain a first solution capable of spinning, a second solution and a solvent incapable of spinning;

step A2; setting the ambient humidity to be 20 ℃ and the relative humidity to be 65%, and taking the first solution, the solvent and the second solution as a sheath solution, a middle solution and a core solution respectively during electrostatic spinning;

step A3: the flow rates of the sheath liquid, the intermediate liquid and the core liquid are respectively 0.2-2.5 ml/h, 0.2-2.5 ml/h and 0.2-2.5 ml/h;

step A4: when the liquid drops flow out of the spinning head, the high-voltage electrostatic generator is turned on, and voltage is applied;

step A5, setting the distance between the spinning head and the fiber collector to be 15cm, and carrying out multi-fluid electrostatic spinning;

step A6, preparing the beaded nanofiber with the core-sheath structure.

Further, in the step a1, the non-spinnable solvents are acetone, ethanol and N-N dimethylacetamide in a volume ratio of 1: 1: 4 in the ratio of (a); the second solution is 0.3g of polyvinylpyrrolidone, and the polyvinylpyrrolidone is placed in 10.0mL of the solvent and stirred by a magnetic stirrer at normal temperature for 12 hours to be fully dissolved to obtain a polyvinylpyrrolidone solution with the concentration of 3% (w/v); the first solution is 0.4g of cellulose acetate, and the solution is fully dissolved in 10.0mL of the solvent at normal temperature through stirring for 12 hours by a magnetic stirrer to obtain a 4% (w/v) cellulose acetate solution.

Further, in the step A3, the flow rates of the sheath fluid, the intermediate fluid and the core fluid are respectively 1.0/1.0/1.0ml/h or 1.0/0.5/1.0 ml/h.

Further, when the flow rates of the sheath liquid, the intermediate liquid and the core liquid are 1.0/1.0/1.0ml/h, respectively, the applied voltage is 11.9KV in step a 4; when the flow rates of the sheath liquid, the intermediate liquid and the core liquid are 1.0/0.5/1.0ml/h, respectively, the voltage applied in step A4 is 10.5 KV.

Further, in the step A1, the non-spinnable solvent is ethanol, and the second solution is 0.5g of polyethylene oxide which is sufficiently dissolved in 10.0mL of the solvent at normal temperature by stirring for 12 hours by a magnetic stirrer to obtain a 5% (w/v) polyethylene oxide solution; the first solution is a shellac solution with a concentration of 50% (w/v) obtained by stirring 5.0g of shellac in 10.0mL of the solvent for 12 hours and fully dissolving at normal temperature by a magnetic stirrer.

Further, in the step A3, the flow rates of the sheath liquid, the intermediate liquid and the core liquid are respectively 0.6/0.2/0.6 ml/h.

Further, in the step a4, the applied voltage is 6 KV.

Compared with the prior art, the invention has the following beneficial effects: the method overcomes the defects of the prior art, provides a multi-fluid electrostatic spinning process, and prepares the beaded nano-fiber with a composite structure in one step and stably, and is characterized in that a non-spinnable solvent is introduced into the middle layer of a plurality of strands of fluid to promote the formation of the beaded nano-fiber with the composite structure.

Drawings

FIG. 1 is a structural view of a multi-fluid electrostatic spinning apparatus of the present invention;

fig. 2 is an internal structural view of a portion a of the three-stage coaxial spinneret of fig. 1;

FIG. 3 is a graph of beaded nanostructured fibers collected in example 1;

FIG. 4 is a graph of beaded nanostructured fibers collected in example 2;

fig. 5 is a graph of beaded nanostructured fibers collected in example 3.

In the figure, 1, a sheath fluid axial flow injection pump; 2. an intermediate liquid axial flow injection pump; 3. a bore fluid axial flow syringe pump; 4. A three-stage coaxial spinning head; 5. a high voltage electrostatic generator; 6. a fiber collector.

Detailed Description

A multi-fluid electrostatic spinning apparatus and a method for preparing beading-structured nanofibers according to the present invention will be described in more detail with reference to the schematic drawings, in which preferred embodiments of the present invention are shown, it being understood that those skilled in the art can modify the present invention described herein while still achieving the advantageous effects of the present invention, and therefore, the following description should be construed as being widely known to those skilled in the art and not as limiting the present invention.

In the description of the present invention, it should be noted that, for the terms of orientation, such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the terms of orientation and positional relationship indicate the orientation or positional relationship illustrated in the drawings, which are merely for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific scope of protection of the present invention

A multi-fluid electrostatic spinning device. As shown in fig. 1 and 2, the multi-fluid electrospinning device includes a sheath fluid axial flow injection pump 1, an intermediate fluid axial flow injection pump 2, a core fluid axial flow injection pump 3, a three-stage coaxial spinneret 4, a high-voltage electrostatic generator 5, and a fiber collector 6. Three syringe pump ends are provided with syringes. The three-stage coaxial spinning head 4 is provided with a sheath liquid interface, an intermediate liquid interface and a core liquid interface, wherein the intermediate liquid interface is directly communicated with the intermediate liquid axial flow injection pump 2 through an injector, high-elasticity flexible rubber tubes are respectively arranged between the injectors of the sheath liquid axial flow injection pump 1 and the core liquid axial flow injection pump 3 and between the sheath liquid interface and the core liquid interface, and the injectors of the sheath liquid axial flow injection pump 1 and the core liquid axial flow injection pump 3 are respectively communicated with the sheath liquid interface and the core liquid interface of the three-stage coaxial spinning head 4 through the high-elasticity flexible rubber tubes. The three-stage coaxial spinning head 4 is connected with a high-voltage electrostatic generator 5 for providing high-voltage static electricity, and the connection mode is that the three-stage coaxial spinning head is matched with crocodile pliers through a lead and is connected with the positive electrode of the high-voltage electrostatic generator 5. The negative pole of high voltage static generator 5 passes through wire and crocodile pincers and communicates with fibre collector 6, makes to form the electric field between tertiary coaxial spinning head 4 and the fibre collector 6, makes things convenient for fibre collector 6 to receive the string of beads nanofiber of preparation, and fibre collector 6 is the cardboard of aluminium foil parcel.

Method for preparing bead-string structured nanofiber through multi-fluid electrostatic spinning device

Example 1:

step one, preparing a spinning solution: acetone, ethanol and N-dimethylacetamide according to a volume ratio of 1: 1: 4 as non-spinnable solvent. 0.3g of polyvinylpyrrolidone and 0.4g of cellulose acetate are weighed and respectively dissolved in 10.0mL of non-spinnable solvent, and then the solution is fully dissolved by stirring for 12 hours at normal temperature through a magnetic stirrer to obtain a polyvinylpyrrolidone solution with the concentration of 3% (w/v) and a cellulose acetate solution with the concentration of 4% (w/v).

Step two, preparing the core-sheath bead nanofiber: the ambient humidity was 20 ℃ and the relative humidity was 65%. In the spinning apparatus shown in FIG. 1, the cellulose acetate solution obtained in the first step is added to the injector of the sheath fluid axial flow injection pump 1, the non-spinnable solvent is added to the injector of the intermediate fluid axial flow injection pump 2, and the polyvinylpyrrolidone solution is added to the injector of the core fluid axial flow injection pump 3, and the sheath fluid axial flow injection pump 1, the intermediate fluid axial flow injection pump 2 and the core fluid axial flow injection pump 3 are respectively started, and the sheath/intermediate/core fluid flow rates are respectively 0.2-2.5 ml/h, 0.2-2.5 ml/h and 0.2-2.5 ml/h, preferably 1.0/1.0/1.0ml/h in the present embodiment.

And step three, when the liquid drops flow out of the three-stage coaxial spinning head 4, opening the high-voltage electrostatic generator 5, applying voltage of 11.9kV, and performing three-fluid coaxial electrostatic spinning under the condition that the distance from the three-stage coaxial spinning head 4 to the fiber collector 6 is 15cm, and finally receiving the bead-string nanofibers with the core-sheath structure on the fiber collector 6 along with the volatilization of the solvent, wherein the bead-string nanofibers are shown in fig. 3.

Example 2:

Step two, preparing the core-sheath bead nanofiber: the ambient humidity was 20 ℃ and the relative humidity was 65%. In the spinning apparatus shown in FIG. 1, the cellulose acetate solution obtained in the first step is added to the injector of the sheath fluid axial flow injection pump 1, the non-spinnable solvent is added to the injector of the intermediate fluid axial flow injection pump 2, and the polyvinylpyrrolidone solution is added to the injector of the core fluid axial flow injection pump 3, and the sheath fluid axial flow injection pump 1, the intermediate fluid axial flow injection pump 2 and the core fluid axial flow injection pump 3 are respectively started, and the sheath/intermediate/core fluid flow rates are respectively 0.2-2.5 ml/h, 0.2-2.5 ml/h and 0.2-2.5 ml/h, preferably 1.0/0.5/1.0ml/h in the present embodiment.

And step three, when the liquid drops flow out of the three-stage coaxial spinning head 4, opening the high-voltage electrostatic generator 5, applying voltage of 10.5kV, and performing three-fluid coaxial electrostatic spinning under the condition that the distance from the three-stage coaxial spinning head 4 to the fiber collector 6 is 15cm, and finally receiving the bead-string nanofibers with the core-sheath structure on the fiber collector 6 along with the volatilization of the solvent, as shown in fig. 4.

Example 3:

step one, preparing a spinning solution: taking ethanol as a non-spinnable solvent, weighing 0.5g of polyoxyethylene and 5.0g of shellac, respectively dissolving in 10.0mL of non-spinnable solvent, and then stirring for 12 hours at normal temperature by a magnetic stirrer to fully dissolve, to obtain 5% (w/v) polyoxyethylene solution and 50% (w/v) shellac solution.

Step two, preparing the core-sheath bead nanofiber: the ambient humidity was 20 ℃ and the relative humidity was 65%. In the spinning device shown in FIG. 1, the shellac solution obtained in the first step is added to the syringe on the sheath liquid axial flow injection pump 1, the non-spinnable solvent is added to the syringe on the intermediate liquid axial flow injection pump 2, and the polyethylene oxide solution is added to the syringe on the core liquid axial flow injection pump 3, and the sheath liquid axial flow injection pump 1, the intermediate liquid axial flow injection pump 2 and the core liquid axial flow injection pump 3 are respectively started, and the sheath/intermediate/core liquid flow rates are respectively 0.2-2.5 ml/h, 0.2-2.5 ml/h and 0.2-2.5 ml/h, preferably 0.6/0.2/0.6ml/h in the present embodiment.

And step three, when the liquid drops flow out of the three-stage coaxial spinning head 4, opening the high-voltage electrostatic generator 5, applying a voltage of 6kV, and performing three-fluid coaxial electrostatic spinning under the condition that the distance from the three-stage coaxial spinning head 4 to the fiber collector 6 is 15cm, and finally receiving the bead-string nanofibers with the core-sheath structure on the fiber collector 6 along with the volatilization of the solvent, as shown in fig. 5.

The polymers to which the present invention relates are not limited to three of the examples, and may be any polymer in combination. The intermediate liquid is not limited to a solvent, and can be any fluid without spinnability, and the three-fluid coaxial electrospinning process is mainly involved in the embodiment of the invention, but the invention is also applicable to other multi-fluid electrospinning processes.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A preparation method of bead nanofiber with a composite structure is characterized in that the method is carried out based on a multi-fluid electrostatic spinning process and comprises the following steps:

step A6, preparing the beaded nanofiber with the core-sheath structure.

2. The method for preparing beaded nano fiber with composite structure as claimed in claim 1, wherein in the step a1, the non-spinnable solvents are acetone, ethanol and N-N dimethylacetamide in a volume ratio of 1: 1: 4 in the ratio of (a); the second solution is 0.3g of polyvinylpyrrolidone, and the polyvinylpyrrolidone is placed in 10.0mL of the solvent and stirred by a magnetic stirrer at normal temperature for 12 hours to be fully dissolved to obtain a polyvinylpyrrolidone solution with the concentration of 3% (w/v); the first solution is 0.4g of cellulose acetate, and the solution is fully dissolved in 10.0mL of the solvent at normal temperature through stirring for 12 hours by a magnetic stirrer to obtain a 4% (w/v) cellulose acetate solution.

3. The method for preparing bead-on-bead nanofibers with composite structure as claimed in claim 2, wherein in step A3, the flow rates of the sheath fluid, the intermediate fluid and the core fluid are 1.0/1.0/1.0ml/h or 1.0/0.5/1.0ml/h respectively.

4. The method for preparing bead nanofibers with composite structure according to claim 3, wherein when the flow rates of the sheath liquid, the intermediate liquid and the core liquid are 1.0/1.0/1.0ml/h, respectively, the applied voltage in step A4 is 11.9 KV; when the flow rates of the sheath liquid, the intermediate liquid and the core liquid are 1.0/0.5/1.0ml/h, respectively, the voltage applied in step A4 is 10.5 KV.

5. The method for preparing beaded nano fiber with composite structure as claimed in claim 1, wherein in step A1, the non-spinnable solvent is ethanol, the second solution is 0.5g of polyethylene oxide dissolved sufficiently in 10.0mL of the solvent at room temperature by stirring with a magnetic stirrer for 12 hours to obtain 5% (w/v) polyethylene oxide solution; the first solution is a shellac solution with a concentration of 50% (w/v) obtained by stirring 5.0g of shellac in 10.0mL of the solvent for 12 hours and fully dissolving at normal temperature by a magnetic stirrer.

6. The method for preparing beaded nano fiber with composite structure as claimed in claim 5, wherein the flow rates of the sheath fluid, the intermediate fluid and the core fluid in step A3 are 0.6/0.2/0.6ml/h respectively.

7. The method for preparing bead nanofibers with composite structure as claimed in claim 6, wherein in step A4, the applied voltage is 6 KV.