Polymer dense membrane and electrostatic spinning preparation method thereof

Abstract

The invention belongs to the technical field of biological materials, and particularly relates to a polymer dense membrane and an electrostatic spinning preparation method thereof, the thickness of the polymer dense membrane is larger than or equal to 25 micrometers, the pore area proportion of the polymer dense membrane is smaller than or equal to 20%, and the polymer dense membrane is prepared through a low-melting-point polymer blending spinning method or a spinning solution dilution method. According to the method, the process defects of the polymer dense membrane are overcome, the pores in the electrostatic spinning membrane are filled on the basis of electrostatic spinning in cooperation with a low-melting-point polymer or solvent spraying mode, so that the polymer dense membrane is formed, and the process difficulty and complexity are greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterials, and particularly relates to a polymer dense film and an electrospinning method for preparing the same. Background Art

[0002] Based on its own bionic microstructure and biocompatibility, the electrospun membrane plays an irreplaceable and important role in surgical fields such as soft tissue enhancement, hernia repair, and prevention of tissue adhesion. Especially at the wound site, the mechanical strength of the electrospinning itself provides a certain physical support to help recovery. However, the electrospun fibers maintain the mechanical effect through the friction generated by the disordered arrangement and mutual entanglement of the fibers, resulting in insufficient mechanical properties and uneven mechanical distribution on the electrospinning surface. Moreover, the electrospun fiber membrane has an extracellular matrix structure and is difficult to achieve the effect of anti-adhesion. The composite of the fiber membrane and the polymer dense membrane is a method to enhance the mechanical properties and anti-adhesion effect of the electrospun fiber membrane. The molecular chain arrangement of the dense membrane is more compact than that of the fiber membrane, with a high degree of crystallization and more excellent mechanical properties. At the same time, the smooth surface of the dense membrane can reduce cell adhesion and proliferation, achieving the effect of anti-adhesion.

[0003] The current polymer dense membrane process generally uses a polymer to prepare a spinning solution, and then the solvent is volatilized through methods such as electrofocusing, flow drying, and vacuum drying to form a polymer dense membrane, or a polymer dense membrane is formed by hot pressing and melting after electrospinning treatment. The above-mentioned preparation methods of polymer dense membranes all have the problems of more operation steps and complex processes, and do not have the prospect of large-scale manufacturing. On the other hand, during the composite process of these polymer dense membranes with the electrospun fiber membrane, they need to be re-laid, and the composite effect is not good under the influence of the interfacial effect. Summary of the Invention

[0004] Aiming at the problems in the prior art, the present invention solves the process defects of polymer dense membranes. Based on electrospinning, in cooperation with a low-melting-point polymer or solvent spraying method, the pores in the electrospun membrane are filled to form a polymer dense membrane, greatly reducing the process difficulty and complexity.

[0005] To achieve the above technical objectives, the technical solution of the present invention is: A polymer dense membrane, wherein the thickness of the polymer dense membrane ≥ 25 μm, and the proportion of the pore area of the polymer dense membrane ≤ 20%, and the polymer dense membrane is obtained by a low-melting-point polymer blending electrospinning method or a spinning solution dilution method.

[0006] The low melting point polymer blending spinning method includes the following steps: a1, preparing a spinning solution and adding a low melting point polymer with a mass volume ratio of 3-7%; a2, adjusting the spinning environment problem to ensure that the spinning environment temperature is higher than the melting point of the low melting point polymer; a3, preparing a polymer dense film by electrospinning: performing electrospinning on the prepared spinning solution to obtain a polymer dense film.

[0007] The spinning solution in a1 is one or more of poly(lactic-co-glycolic acid), poly(L-lactide-co-caprolactone), polylactic acid, polycaprolactone, polyvinylidene fluoride, polybutylene succinate, poly(butylene succinate-co-butylene terephthalate), polyvinyl alcohol, polypropylene, zein, and polyacrylonitrile; the solvent of the spinning solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and ethylene glycol monomethyl ether.

[0008] Furthermore, the spinning solution adopts a mixture of poly(ethylene glycol-lactic acid) copolymer and poly(lactic-co-glycolic acid), and the mass ratio of poly(ethylene glycol-lactic acid) copolymer to poly(lactic-co-glycolic acid) is 3:7. The spinning solvent is a mixed solution of N,N-dimethylformamide and acetone with a mass ratio of 1:1. The low melting point polymer adopts polyethylene glycol 400 with a melting point of 6 °C and a mass volume ratio of 5%; the temperature of the spinning environment is 23 °C.

[0009] The spinning solution dilution method includes the following steps: b1, preparing a spinning solution and a spinning solvent identical to the spinning solution; b2, performing electrospinning with multiple nozzles, and a plastic spray nozzle with an adjustable spraying rate is arranged at the midpoint between every two spinning nozzles. The plastic spray nozzle is connected to the spinning solvent and performs synchronous atomizing spraying during the electrospinning process; after electrospinning, it is dried to obtain a polymer dense film.

[0010] The spinning solution in b1 is one or more of poly(lactic-co-glycolic acid), poly(L-lactide-co-caprolactone), polylactic acid, polycaprolactone, polyvinylidene fluoride, polybutylene succinate, poly(butylene succinate-co-butylene terephthalate), polyvinyl alcohol, polypropylene, zein, and polyacrylonitrile; the spinning solvent adopts one or more of N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and ethylene glycol monomethyl ether.

[0011] The spraying rate of the spinning solvent and the spinning solution in b2 is 0.1-0.9.

[0012] Further, the spinning solution adopts a mixture of polyethylene glycol-lactic acid copolymer and polylactic acid-glycolic acid copolymer, and the mass ratio of polyethylene glycol-lactic acid copolymer to polylactic acid-glycolic acid copolymer is 15:85. The spinning solvent is a mixed solution of N,N-dimethylformamide and acetone with a mass ratio of 1:1, and the spraying rate of the spinning solvent to the spinning solution is 0.5.

[0013] As can be seen from the above description, the present invention has the following advantages: 1. The present invention solves the process defects of polymer dense membranes. Based on electrospinning, it cooperates with the method of low melting point polymer or solvent spraying to fill the pores in the electrospun membrane, thereby forming a polymer dense membrane, greatly reducing the process difficulty and complexity.

[0014] 2. The present invention uses polyethylene glycol 400 as the low melting point polymer, which remains in a molten state during the electrospinning process, and cooperates with the formation of gradient curing during the curing process of the spinning polymer, thereby realizing the filling of pores by polyethylene glycol.

[0015] 3. The present invention utilizes the differences between the spinning solvent and the spinning solution and their state differences in electrospinning, and also utilizes the solubility of the spinning solvent in electrospun filaments to ensure the surface fluidity and adhesion of electrospun filaments, thereby reducing the porosity of the spun fiber membrane. Description of the Drawings

[0016] Figures 1-4 is the electron microscope image of the polymer dense membrane prepared in Examples 1-4 of the present invention.

[0017] Figure 5 is the distribution diagram of the spinning nozzle and the plastic spray nozzle in the spinning solvent dilution method in this example, where 1 is the spinning nozzle and 2 is the plastic spray nozzle.

[0018] Figures 6-9 is the electron microscope image of the polymer dense membrane prepared in Examples 5-8 of the present invention. Detailed Embodiments

[0019] Combined with Figures 1-9 , the specific embodiments of the present invention are described in detail, but no limitations are made to the claims of the present invention.

[0020] Example 1 The method for preparing a polymer dense membrane by low melting point polymer blending electrospinning includes the following steps: A spinning solution with a mass ratio of 53% was prepared by mixing a polyethylene glycol - lactic acid copolymer and a poly(lactic - co - glycolic acid) copolymer at a mass ratio of 30:70 with a spinning solvent of N,N - dimethylformamide and acetone at a volume ratio of 1:1. Then, polyethylene glycol 400 with a melting point of 6 °C was added at a mass - to - volume ratio of 1%. The finally prepared low - melting - point polymer mixed spinning solution was electrospun at an ambient temperature of 23 °C to obtain an electrospun polymer dense membrane.

[0021] Example 2 The method for preparing a polymer dense membrane by low - melting - point polymer blending electrospinning includes the following steps: A spinning solution with a mass ratio of 53% was prepared by mixing a polyethylene glycol - lactic acid copolymer and a poly(lactic - co - glycolic acid) copolymer at a mass ratio of 30:70 with a spinning solvent of N,N - dimethylformamide and acetone at a volume ratio of 1:1. Then, polyethylene glycol 400 with a melting point of 6 °C was added at a mass - to - volume ratio of 3%. The finally prepared low - melting - point polymer mixed spinning solution was electrospun at an ambient temperature of 23 °C to obtain an electrospun polymer dense membrane.

[0022] Example 3 The method for preparing a polymer dense membrane by low - melting - point polymer blending electrospinning includes the following steps: A spinning solution with a mass ratio of 53% was prepared by mixing a polyethylene glycol - lactic acid copolymer and a poly(lactic - co - glycolic acid) copolymer at a mass ratio of 30:70 with a spinning solvent of N,N - dimethylformamide and acetone at a volume ratio of 1:1. Then, polyethylene glycol 400 with a melting point of 6 °C was added at a mass - to - volume ratio of 5%. The finally prepared low - melting - point polymer mixed spinning solution was electrospun at an ambient temperature of 23 °C to obtain an electrospun polymer dense membrane.

[0023] Example 4 The method for preparing a polymer dense membrane by low - melting - point polymer blending electrospinning includes the following steps: A spinning solution with a mass ratio of 53% was prepared by mixing a polyethylene glycol - lactic acid copolymer and a poly(lactic - co - glycolic acid) copolymer at a mass ratio of 30:70 with a spinning solvent of N,N - dimethylformamide and acetone at a volume ratio of 1:1. Then, polyethylene glycol 400 with a melting point of 6 °C was added at a mass - to - volume ratio of 7%. The finally prepared low - melting - point polymer mixed spinning solution was electrospun at an ambient temperature of 23 °C to obtain an electrospun polymer dense membrane.

[0024] The electron micrographs of the polymer dense membranes of Examples 1 - 4 are as Figures 1-4 shown, and the pore area ratios are as follows:

[0025] From the data of the above Examples 1-4, it can be seen that the pore area with a mass ratio of 1% does not meet the technical requirements of the polymer dense membrane, and the electrospun dense membrane prepared with a mass ratio of 10% will leak due to the too high solubility of polyethylene glycol. Therefore, when polyethylene glycol is added in a content of 3-7% mass / volume ratio, the pores in the electrospun fiber membrane can be effectively sealed, thus forming a polymer dense membrane.

[0026] Example 5 Preparing a polymer dense membrane by the spinning solution dilution method, comprising the following steps: Preparing a spinning solution with a mass ratio of 53% by mixing a polyethylene glycol-lactic acid copolymer and a poly(lactic-co-glycolic acid) copolymer in a mass ratio of 15:85 with a spinning solvent of N,N-dimethylformamide and acetone in a volume ratio of 1:1. As Figure 5 shown, (1) is a spinning nozzle, and (2) is a plastic spray nozzle. Set the ratio of the liquid spraying rate of the spray nozzle to the liquid spraying rate of the spinning nozzle to be 0.1.

[0027] Example 6 Preparing a polymer dense membrane by the spinning solution dilution method, comprising the following steps: Preparing a spinning solution with a mass ratio of 53% by mixing a polyethylene glycol-lactic acid copolymer and a poly(lactic-co-glycolic acid) copolymer in a mass ratio of 15:85 with a spinning solvent of N,N-dimethylformamide and acetone in a volume ratio of 1:1. As Figure 5 shown, (1) is a spinning nozzle, and (2) is a plastic spray nozzle. Set the ratio of the liquid spraying rate of the spray nozzle to the liquid spraying rate of the spinning nozzle to be 0.3.

[0028] Example 7 Preparing a polymer dense membrane by the spinning solution dilution method, comprising the following steps: Preparing a spinning solution with a mass ratio of 53% by mixing a polyethylene glycol-lactic acid copolymer and a poly(lactic-co-glycolic acid) copolymer in a mass ratio of 15:85 with a spinning solvent of N,N-dimethylformamide and acetone in a volume ratio of 1:1. As Figure 5 shown, (1) is a spinning nozzle, and (2) is a plastic spray nozzle. Set the ratio of the liquid spraying rate of the spray nozzle to the liquid spraying rate of the spinning nozzle to be 0.5.

[0029] Example 8 Preparing a polymer dense membrane by the spinning solution dilution method, comprising the following steps: Preparing a spinning solution with a mass ratio of 53% by mixing a polyethylene glycol-lactic acid copolymer and a poly(lactic-co-glycolic acid) copolymer in a mass ratio of 15:85 with a spinning solvent of N,N-dimethylformamide and acetone in a volume ratio of 1:1. As Figure 5 shown, (1) is a spinning nozzle, and (2) is a plastic spray nozzle. Set the ratio of the liquid spraying rate of the spray nozzle to the liquid spraying rate of the spinning nozzle to be 0.7.

[0030] The electron micrographs of the polymer dense membranes of Examples 5-8 are as Figures 6-9 shown, and the proportion of the pore area is as follows:

[0031] From the data of the above Examples 5-8, it can be seen that when the ratio of the liquid spraying rate of the spray head to the spinning head rate is 0.1-0.7, the proportion of the pore area meets the technical requirements of the polymer dense membrane, that is, the above method can obtain a polymer dense membrane that meets the requirements.

[0032] It can be understood that the above specific description of the present invention is only for explaining the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as it meets the usage requirements, it is within the protection scope of the present invention.

Claims

1. A polymer dense membrane, characterized in that: The thickness of the aggregated dense membrane ≥ 25 μm, and the proportion of the pore area of the polymer dense membrane ≤ 20%.

2. The polymer dense film according to claim 1, wherein: The polymer dense membrane is prepared by a low melting point polymer blending spinning method or a spinning solution dilution method.

3. The polymer dense film according to claim 2, characterized in that: The low melting point polymer blending spinning method includes the following steps: a1, preparing a spinning solution and adding 3-7% (mass / volume ratio) of a low melting point polymer; a2, adjusting the spinning environment temperature to ensure that the spinning environment temperature is higher than the melting point of the low melting point polymer; a3, electrospinning to prepare a polymer dense membrane: electrospinning the prepared spinning solution to obtain a polymer dense membrane.

4. The polymer dense film according to claim 3, wherein: The spinning solution in a1 is one or more of poly(lactic-co-glycolic acid), poly(L-lactide-co-caprolactone), polylactic acid, polycaprolactone, polyvinylidene fluoride, polybutylene succinate, poly(butylene succinate-co-butylene terephthalate), polyvinyl alcohol, polypropylene, zein, polyacrylonitrile; the solvent of the spinning solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and ethylene glycol monomethyl ether.

5. The polymer dense film according to claim 4, characterized in that: The spinning solution is a mixture of poly(ethylene glycol-lactic acid) copolymer and poly(lactic-co-glycolic acid), and the mass ratio of poly(ethylene glycol-lactic acid) copolymer to poly(lactic-co-glycolic acid) is 3:

7. The spinning solvent is a mixed solution of N,N-dimethylformamide and acetone with a mass ratio of 1:

1. The low melting point polymer is polyethylene glycol 400 with a melting point of 6 °C and a mass / volume ratio of 5%; the temperature of the spinning environment is 23 °C.

6. The polymer dense film according to claim 2, wherein: The spinning solution dilution method includes the following steps: b1, preparing a spinning solution and a spinning solvent identical to the spinning solution; b2, performing electrospinning using multiple nozzles, and arranging an adjustable spray rate plastic spray nozzle at the midpoint between every two spinning nozzles. The plastic spray nozzle is connected to the spinning solvent and performs synchronous atomizing spraying during electrospinning; after electrospinning, it is dried to obtain a polymer dense membrane.

7. The polymer dense membrane according to claim 6, wherein: The spinning solution in b1 is one or more of poly(lactic-co-glycolic acid), poly(L-lactide-co-caprolactone), polylactic acid, polycaprolactone, polyvinylidene fluoride, polybutylene succinate, poly(butylene succinate-co-butylene terephthalate), polyvinyl alcohol, polypropylene, zein, polyacrylonitrile; the spinning solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, and ethylene glycol monomethyl ether.

8. The polymer dense film according to claim 6, characterized in that: The spraying rate of the spinning solvent and the spinning solution in b2 is 0.1-0.

9.

9. The polymer dense film according to claim 6, wherein: The spinning solution is a mixture of poly(ethylene glycol-lactic acid) copolymer and poly(lactic-co-glycolic acid), and the mass ratio of poly(ethylene glycol-lactic acid) copolymer to poly(lactic-co-glycolic acid) is 15:

85. The spinning solvent is a mixed solution of N,N-dimethylformamide and acetone with a mass ratio of 1:1, and the spraying rate of the spinning solvent and the spinning solution is 0.5.

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