Nanofiber with adjustable biodegradation period, preparation method of nanofiber, non-woven fabric and application of non-woven fabric

Abstract

The invention belongs to the field of electrostatic spinning, and relates to a nanofiber with an adjustable biodegradation period, a preparation method of the nanofiber, a non-woven fabric and application of the non-woven fabric. The nanofiber is PBST fiber, and the average diameter of the PBST fiber is not more than 800 nm, preferably 50-600 nm; based on the total weight of the PBST, the content of a butylene succinate (BS) chain segment in the PBST is 40 to 90 weight percent, preferably 50 to 80 weight percent. The PBST nanofiber provided by the invention is simple in preparation method, good in continuity, safe, environment-friendly and suitable for industrial production; the obtained PBST nanofiber has biodegradability and no solvent residue, the biodegradation period is 40-80 days, and the PBST nanofiber can be used for products such as degradable packages, mulching films, shopping bags and medical sanitary materials.

Description

Technical Field

[0001] This invention belongs to the field of electrospinning, specifically relating to a biodegradable nanofiber, its preparation method, nonwoven fabric, and applications. Background Technology

[0002] In recent years, white pollution has plagued countries worldwide, prompting a continuous search for biodegradable materials that can be used under a wide range of conditions. Biodegradation refers to the complete degradation into carbon dioxide and water under natural conditions without soil pollution. However, currently available commercially available biodegradable resins degrade too quickly under natural conditions, failing to meet practical application requirements. Therefore, additives must be added to regulate the degradation cycle. However, adding additives not only increases costs but also negatively impacts soil microorganisms.

[0003] Electrospinning is a new fiber-making technology developed based on electrospinning. Its principle involves stretching a solution or polymer droplet under a high-voltage electric field into a fiber through charge interaction, which is then deposited onto a current collector to form a nanofiber membrane. Electrospinning offers advantages such as simple operation, low cost, and high yield for nanofiber membrane preparation. Furthermore, the prepared nanofiber membranes, due to their extremely high specific surface area and porosity, have broad application prospects in filtration materials, flexible pressure sensors, antibacterial and antiviral materials, and mulch film protection materials. However, the application scope of traditional electrospun nanofiber membranes is usually limited, and they cannot simultaneously meet the requirements of usability and biodegradability.

[0004] Therefore, there is an urgent need to develop a fiber and products with good overall performance and a controllable biodegradation cycle. Summary of the Invention

[0005] The purpose of this invention is to solve the aforementioned problems in the prior art and to provide a nanofiber membrane and its preparation method. The nanofiber membrane uses PBST as raw material. PBST is a random copolyester of butylene terephthalate (BT) and butylene succinate (BS), composed of BT and BS segments. The BT segments are rigid, while the BS segments are flexible. The combination of the two endows the nanofiber membrane with good mechanical properties and a certain degree of flexibility and elasticity. At the same time, by adjusting the content of BS segments, the biodegradation cycle of the nanofiber membrane can be varied within a wide range, thereby meeting the requirements of use in multiple fields and biodegradability, such as for biodegradable packaging, mulch films, shopping bags, medical and sanitary materials, and other products.

[0006] To achieve the above objectives, a first aspect of the present invention provides a nanofiber with an adjustable biodegradation cycle, wherein the nanofiber is a PBST fiber and the average diameter of the PBST fiber does not exceed 800 nm, preferably 50-600 nm.

[0007] Based on the total weight of PBST, the content of butylene succinate (BS) segments in the PBST is 40-90 wt%, preferably 50-80 wt%.

[0008] A second aspect of the present invention provides a method for preparing the biodegradable nanofibers, comprising the following steps:

[0009] (1) Dissolve PBST resin in spinning solvent to obtain PBST spinning solution;

[0010] (2) The PBST spinning solution obtained in step (1) is fed into a solution electrospinning machine and sprayed onto the receiver by the nozzle to obtain the nanofiber with adjustable biodegradation cycle.

[0011] A third aspect of the present invention provides a nonwoven fabric composed of the aforementioned biodegradable periodic nanofibers.

[0012] A fourth aspect of the invention provides the application of the described nonwoven fabric in the fields of packaging, mulch film, shopping bags, and medical and hygiene materials.

[0013] The PBST nanofiber preparation method provided by this invention is simple, continuous, safe and environmentally friendly, and suitable for industrial production. The obtained PBST nanofibers are biodegradable, have no solvent residue, and have a biodegradation cycle of 40-80 days. They can be used in biodegradable packaging, mulch films, shopping bags, medical and sanitary materials and other products.

[0014] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0015] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0016] To achieve the above objectives, a first aspect of the present invention provides a nanofiber with an adjustable biodegradation cycle, wherein the nanofiber is a PBST fiber and the average diameter of the PBST fiber does not exceed 800 nm, preferably 50-600 nm.

[0017] Based on the total weight of PBST, the content of butylene succinate (BS) segments in the PBST is 40-90 wt%, preferably 50-80 wt%.

[0018] PBST is a random copolyester of butylene terephthalate (BT) and butylene succinate (BS). Compared with pure PBT or PBS, it exhibits superior mechanical properties. The overall flexibility of PBST increases significantly with the increase of BS segments. Therefore, the final properties of the material can be adjusted by varying the proportions of BS segments in the PBST chain. However, a high BT segment content leads to higher crystallinity, which is detrimental to processing, while also increasing rigidity and prolonging the degradation cycle.

[0019] In this invention, the PBST resin is prepared in the laboratory by means of a two-step esterification reaction and a one-step copolymerization reaction.

[0020] According to the present invention, preferably, the weight-average molecular weight of the PBST is 120,000-1,000,000, more preferably 140,000-300,000.

[0021] In this invention, the molecular weight of PBST resin is one of the key factors in solving the nanofiber problem. If the molecular weight of PBST is too small, the solution viscosity is low, the fiber-forming performance is weak, and it is not conducive to electrospinning. If the molecular weight of PBST is too large, the resulting solution is uneven or has high viscosity, resulting in poor fluidity, which is not conducive to electrospinning and leads to a large degree of fiber unevenness.

[0022] A second aspect of the present invention provides a method for preparing the biodegradation-cycle-tunable nanofiber membrane, comprising the following steps:

[0023] (1) Dissolve PBST resin in spinning solvent to obtain PBST spinning solution;

[0024] (2) The PBST spinning solution obtained in step (1) is fed into a solution electrospinning machine and sprayed onto the receiver by the nozzle to obtain the nanofiber membrane with adjustable biodegradation cycle.

[0025] According to the present invention, preferably, the process parameters of the solution electrospinning machine include: an ambient temperature of 20-40℃, an ambient humidity of 0-30%, a nozzle voltage of 8-30kV, a receiver voltage of -10-0kV; a distance between the nozzle and the receiver of 20-600mm; and a solution ejection rate of 1.0-6.0mL / h, preferably 1.5-4.0mL / h.

[0026] According to the present invention, preferably, the spinning solvent is dichloromethane or a mixed solvent containing dichloromethane, and the mass concentration of PBST in the PBST spinning solution is 5-30 wt%, preferably 8-18 wt%, and more preferably 12-16 wt%.

[0027] According to the present invention, preferably, the spinning solvent further contains at least one of trifluoroacetic acid, hexafluoroisopropanol and N,N-dimethylformamide.

[0028] Preferably, the spinning solvent is selected from at least one of the following: a trifluoroacetic acid-dichloromethane system with a volume ratio of 1:9-5:5, a hexafluoroisopropanol-dichloromethane system with a volume ratio of 2:8-7:3, and an N,N-dimethylformamide-dichloromethane system with a volume ratio of 2:8-4:6.

[0029] In this invention, the solvent used is a low-boiling-point volatile organic solvent that can evaporate completely, so that the final composite fiber membrane has no solvent residue.

[0030] According to the present invention, preferably, the orifice diameter of the nozzle is 0.1-2.0 mm, more preferably 0.2-1.0 mm.

[0031] According to the present invention, preferably, the receiver is in the shape of a plane, a curved surface, an arc surface, or a circular roller.

[0032] According to the present invention, preferably, the linear velocity of the receiver is 0.1-500 m / min, more preferably 5-200 m / min.

[0033] A third aspect of the present invention provides a nonwoven fabric composed of the aforementioned biodegradable periodic nanofibers.

[0034] According to the present invention, preferably, the tensile stress of the nonwoven fabric is not less than 400 kPa, the elongation at break is not less than 20%, and the biodegradation period is 40-80 days.

[0035] According to the present invention, preferably, the thickness of the nonwoven fabric is 50-200 μm.

[0036] A fourth aspect of the invention provides the application of the described nonwoven fabric in the fields of packaging, mulch film, shopping bags, and medical hygiene materials (such as wound repair and bandaging materials).

[0037] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0038] Example 1

[0039] A 15% (w / w) PBST (molecular weight 140,000, BS segment content 40%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 3:7) was sprayed onto a winding roller from a 0.3 mm orifice at a rate of 1.0 mL / h. A +20 kV positive voltage was applied to the spray nozzle, while a 0 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 100 mm, and the winding roller rotated at 100 m / min. After 20 min, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 500 nm, a thickness of 103 μm, a tensile stress of 400 kPa, an elongation at break of 50%, and a biodegradability period of 45 days.

[0040] Example 2

[0041] A 5% (w / w) PBST (molecular weight 120,000, BS segment content 50%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 3:7) was sprayed onto a winding roller from a 0.1 mm orifice at a rate of 1.0 mL / h. The nozzle was supplied with a +23 kV positive voltage, and the winding roller was supplied with a -7 kV voltage. The vertical distance between the nozzle and the winding roller was 200 mm, and the winding roller rotated at 200 m / min. After 20 min, the nonwoven fabric on the winding roller was collected. The nonwoven fabric was composed of fibers with an average diameter of 50 nm, a thickness of 50 μm, a tensile stress of 450 kPa, an elongation at break of 80%, and a biodegradability period of 60 days.

[0042] Example 3

[0043] A 30% (w / w) PBST (molecular weight 100,000, BS segment content 90%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 3:7) was sprayed onto a winding roller from a 0.2 mm orifice at a rate of 6.0 mL / h. A +20 kV positive voltage was applied to the spray nozzle, and a -10 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 300 mm, and the winding roller rotated at 200 m / min. After 20 min, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 400 nm, a thickness of 200 μm, a tensile stress of 400 kPa, an elongation at break of 100%, and a biodegradability period of 40 days.

[0044] Example 4

[0045] A 15% (w / w) PBST (molecular weight 150,000, BS segment content 50%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 3:7) was sprayed onto a winding roller from a 0.8 mm orifice at a rate of 6.0 mL / h. A +20 kV positive voltage was applied to the spray nozzle, and a -10 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 200 mm, and the winding roller rotated at 200 m / min. After 20 min, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 600 nm, a thickness of 150 μm, a tensile stress of 500 kPa, an elongation at break of 50%, and a biodegradability period of 50 days.

[0046] Example 5

[0047] A 15% (w / w) PBST (molecular weight 150,000, BS segment content 50%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 4:6) was sprayed onto a winding roller at a rate of 3.0 mL / h through a 0.5 mm orifice nozzle. A +20 kV positive voltage was applied to the nozzle, and a -10 kV voltage was applied to the winding roller. The vertical distance between the nozzle and the winding roller was 200 mm, and the winding roller rotated at 200 m / min. After 20 minutes, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 500 nm, a thickness of 120 μm, a tensile stress of 420 kPa, an elongation at break of 60%, and a biodegradability period of 55 days.

[0048] Example 6

[0049] A 15% (w / w) PBST (molecular weight 120,000, BS segment content 50%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 5:5) was sprayed onto a winding roller from a 0.2 mm orifice at a rate of 2.0 mL / h. A +20 kV positive voltage was applied to the spray nozzle, and a -10 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 300 mm, and the winding roller rotated at 300 m / min. After 20 minutes, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 100 nm, a thickness of 70 μm, a tensile stress of 600 kPa, an elongation at break of 90%, and a biodegradability period of 60 days.

[0050] Example 7

[0051] A 15% (w / w) PBST (molecular weight 120,000, BS segment content 50%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 5:5) was sprayed onto a winding roller from a 0.1 mm orifice at a rate of 2.0 mL / h. A +16 kV positive voltage was applied to the nozzle, and a -2 kV voltage was applied to the winding roller. The vertical distance between the nozzle and the winding roller was 100 mm, and the winding roller rotated at 200 m / min. After 20 minutes, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 80 nm, a thickness of 50 μm, a tensile stress of 700 kPa, an elongation at break of 110%, and a biodegradability period of 80 days.

[0052] Example 8

[0053] A 12% (w / w) PBST (molecular weight 100,000, BS segment content 50%) trifluoroacetic acid-dichloromethane solution (trifluoroacetic acid to dichloromethane volume ratio 3:7) was sprayed onto a winding roller from a 0.1 mm orifice at a rate of 2.0 mL / h. A +16 kV positive voltage was applied to the spray nozzle, and a -2 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 200 mm, and the winding roller rotated at 100 m / min. After 20 minutes, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 50 nm, a thickness of 50 μm, a tensile stress of 720 kPa, an elongation at break of 150%, and a biodegradability period of 80 days.

[0054] Example 9

[0055] A 15% (w / w) PBST (molecular weight 120,000, BS segment content 50%) hexafluoroisopropanol-dichloromethane solution (hexafluoroisopropanol to dichloromethane volume ratio 5:5) was sprayed onto a winding roller from a 0.2 mm orifice at a rate of 2.0 mL / h. A +20 kV positive voltage was applied to the spray nozzle, and a -10 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 300 mm, and the winding roller rotated at 300 m / min. After 20 minutes, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 100 nm, a thickness of 100 μm, a tensile stress of 450 kPa, an elongation at break of 70%, and a biodegradability period of 50 days.

[0056] Example 10

[0057] A 15% (w / w) PBST (molecular weight 120,000, BS segment content 50%) N,N-dimethylformamide-dichloromethane solution (N,N-dimethylformamide to dichloromethane volume ratio 5:5) was sprayed onto a winding roller from a 0.2 mm orifice at a rate of 2.0 mL / h. A +20 kV positive voltage was applied to the spray nozzle, and a -10 kV voltage was applied to the winding roller. The vertical distance between the spray nozzle and the winding roller was 300 mm, and the winding roller rotated at 300 m / min. After 20 minutes, the nonwoven fabric on the winding roller was collected. The nonwoven fabric consisted of fibers with an average diameter of 100 nm, a thickness of 120 μm, a tensile stress of 500 kPa, an elongation at break of 80%, and a biodegradability period of 55 days.

[0058] Comparative Example 1

[0059] The only difference between this comparative example and Example 1 is that it uses PBST (molecular weight 50,000, BS segment content 30%). The nozzle dripping and fiber breakage issues were severe, making it impossible to obtain PBST fibers.

[0060] Comparative Example 2

[0061] The only difference between this comparative example and Example 1 is the use of PBST (molecular weight 1.1 million, BS segment content 98%). The solution easily clogs the spinneret, preventing continuous and normal spinning.

[0062] Comparative Example 3

[0063] The only difference between this embodiment and Example 1 is that the solvent is a dichloromethane solution. Electrospinning cannot be achieved in this embodiment.

[0064] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0065] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A biodegradable nanofiber with adjustable degradation period, characterized in that, The nanofiber is a PBST fiber, and the average diameter of the PBST fiber is not more than 800 nm, preferably 50-600 nm. The content of butane diol succinate (BS) segment in the PBST is 40-90 wt%, preferably 50-80 wt% based on the total weight of the PBST.

2. The biodegradation period-adjustable nanofiber according to claim 1, wherein, The weight average molecular weight of the PBST is 100000-1000000, preferably 120000-300000.

3. The method for preparing the biodegradable nanofibers according to claim 1 or 2, characterized in that, The method comprises the following steps: (1) dissolving the PBST resin in a spinning solvent to obtain a PBST spinning solution; (2) feeding the PBST spinning solution obtained in step (1) into a solution electrospinning machine, and spraying the spinning solution from a nozzle to a receiver to obtain the nanofiber with adjustable biodegradation period.

4. The production method according to claim 3, wherein The process parameters of the solution electrospinning machine include: ambient temperature of 20-40℃, ambient humidity of 0-30%, nozzle voltage of 8-30 kV, receiver voltage of -10-0 kV; the distance between the nozzle and the receiver is 20-600 mm; the spraying speed of the nozzle is 1.0-6.0 mL / h, preferably 1.5-4.0 mL / h.

5. The production method according to claim 3, wherein The spinning solvent is dichloromethane or a mixed solvent containing dichloromethane, and the mass concentration of the PBST in the PBST spinning solution is 5-30 wt%, preferably 8-18 wt%, more preferably 12-16 wt%.

6. The production method according to claim 5, wherein The spinning solvent further contains at least one of trifluoroacetic acid, hexafluoroisopropanol and N,N-dimethylformamide; Preferably, the spinning solvent is selected from at least one of a trifluoroacetic acid-dichloromethane system with a volume ratio of 1:9-5:5, a hexafluoroisopropanol-dichloromethane system with a volume ratio of 2:8-7:3 and an N,N-dimethylformamide-dichloromethane system with a volume ratio of 2:8-4:

6.

7. The production method according to claim 3, wherein The pore size of the nozzle is 0.1-2.0 mm, preferably 0.2-1.0 mm.

8. The production method according to claim 3, wherein The receiver has a shape of a plane, a curved surface, an arc surface or a circular roller.

9. The production method according to claim 8, wherein The linear speed of the receiver is 0.1-500 m / min, preferably 5-200 m / min.

10. A nonwoven fabric, characterized by The non-woven fabric is composed of the nanofiber with adjustable biodegradation period according to any one of claims 1-3.

11. The nonwoven fabric according to claim 10, wherein The tensile stress of the non-woven fabric is not less than 400 KPa, the elongation at break is not less than 20%, and the biodegradation period is 40-80 days.

12. The nonwoven fabric according to claim 10, wherein The thickness of the non-woven fabric is 50-200 μm.

13. The use of the non-woven fabric according to any one of claims 10-12 in the fields of packaging, mulching film, shopping bag and medical and sanitary material.