Background technology
Electrostatic spinning is current unique technology that can prepare continuous superfine nano fiber, and this technology can be spun into nanofiber with the polymer (like polyolefin, polyamide, polyester, aromatic polyamide, polyacrylamide, acrylate copolymer and various biopolymer such as DNA, polypeptide, other conducting polymer or opto-electrical polymers etc.) that various traditional spining technology is used.Electrostatic spinning technique is through applying high-tension electricity between spinning head and receiving pole, and polymer solution forms taylor cone at spinning head under action of high voltage; Continue to increase voltage to certain value, have that a jet body forms and fly to receiving pole at a high speed, a series of crooked erratic processes of jet body process receive high-speed stretch, and in flight course owing to solvent evaporates solidify to form the superfine nano fiber.When polymer fiber diameter is reduced to nanoscale by micron order, some absorbing performances can appear in fiber, as high-specific surface area, surface-functionalized, improve the fibre machinery performance through the controlling fiber institutional framework.These performances make the electrostatic spinning polymer nanofiber in a lot of fields, like fields such as filtration, catalysis, fiber reinforcement, wound repair, organizational project, medicament slow releases, have important use and are worth.
Polyvinyl alcohol is a kind of hydrophily semicrystalline polymeric, because its good chemical stability, heat resistance, good physical property, biocompatibility and with low cost, and be with a wide range of applications.Polyvinyl alcohol obtains broad research owing to its property in electrostatic spinning, like the influence to polyvinyl alcohol nano film pattern such as spinning parameter, SOLUTION PROPERTIES, solution concentration, polymer molecular weight, alcoholysis degree.But also fewer about the heat endurance of the polyvinyl alcohol nano film of electrostatic spinning preparation and mechanical property research.Generally electrostatic spinning system nanofiber film dynamic performance is poor in addition, has limited some application of nanofiber like this.
There is bibliographical information to pass through polyvinyl alcohol and other materials (like silica; CNT; Titanium dioxide etc.) mix and to carry out electrostatic spinning and can obtain composite nano fiber, the heat endurance and the mechanical property of the nano fibrous membrane through these methods preparations are increased.But these methods prepare in the process, and institute's substance is not easy even dispersion, need multistep to handle; The amount of adding in addition is bigger, and cost is also than higher; Through introducing the polyvinyl alcohol nano film that chemical cross-linking agent can obtain chemical crosslinking; Its resistance to water and mechanical property are increased; But this method prepares in the process, uses aldehydes and strong acid to come cross-linking polyvinyl alcohol as catalyst usually, has certain toxicity; Cross-linking reaction is wayward in whole spinning process in addition, and tunica fibrosa biocompatibility after crosslinked and degradability descend.
Through adding the 3rd good component with low cost on a small quantity, nontoxic, water-soluble in polymer solution; Directly carry out electrostatic spinning; Chemical reaction not taking place and not having influence under the prerequisite of polyvinyl alcohol nano film biocompatibility and degradability, obtain the polyvinyl alcohol nano film that heat endurance and mechanical property significantly improve.This method can overcome some shortcomings that said method exists, for the good polyvinyl alcohol nano of electrostatic spinning processability provides a kind of new method.
Summary of the invention
The invention reside in provides a kind of new method that improves electrostatic spinning polyvinyl alcohol nano film heat endurance and mechanical property; This method is simple to operate, and is with low cost, and effect is remarkable; Environmental protection provides a kind of new method for improving electrostatic spinning nano tunica fibrosa heat endurance and mechanical property.
The present invention realizes through following technical scheme:
The present invention mainly utilizes electrostatic spinning technique, uses water as solvent, in poly-vinyl alcohol solution, adds a series of inorganic compounds, and the nano fibrous membrane heat endurance and the mechanical property of preparation significantly improve.
A kind of preparation method who improves polyvinyl alcohol electrostatic spinning nano fibrous membrane heat endurance and mechanical property, its step is following:
The preparation of A, electrostatic spinning solution: adding in the entry PVAC polyvinylalcohol fully, dissolving obtains solution; The concentration of PVA is 8wt% ~ 20wt%; Then sodium chloride, potassium chloride, sodium sulphate, sodium carbonate, sodium acid carbonate, NaOH or boric acid are added above-mentioned solution; Addition is 0.01 wt% ~ 3.0wt%, continues in the interpolation process to stir, and leaves standstill and obtains the homogeneous transparent spinning solution;
B, electrostatic spinning technique prepare nano fibrous membrane: the poly-vinyl alcohol solution of the inorganic-containing compound of the abundant dissolving that will prepare is packed in the syringe, and is fixed on the propeller of electrostatic spinning apparatus, prepares the polyvinyl alcohol nano film through electrostatic spinning.Spinning temperature is 20 ~ 50 ℃, and the spinning solution fltting speed is 0.001 ~ 0.005mm/s, and spinning voltage is 10 ~ 45kV, and spinning head is 8 ~ 25cm to the distance of receiving pole, time of reception 5-10h;
C, nano fibrous membrane post processing: the tunica fibrosa of preparation is carried out dried in vacuum drying chamber, drying at room temperature is stored in the drier subsequent use;
D, the batten that the nano fibrous membrane of above-mentioned preparation is cut into 50mm * 10mm carry out extension test, and every kind of tunica fibrosa is measured five times; Nano fibrous membrane with preparation carries out thermogravimetic analysis (TGA) respectively in addition.
Preparation method of the present invention is simple, and spinning process is stable, uses common inorganic compound with low cost; Directly the heat endurance and the mechanical property of the polyvinyl alcohol nano film of electrostatic spinning preparation significantly improve; Make it filter, biology, aspects such as medicament slow release have broader applications and are worth.
The specific embodiment
Specifically describe the present invention through embodiment below.
Embodiment 1:
The preparation of pure polyvinyl alcohol nano film: 1, take by weighing 1.6g polyvinyl alcohol (alcoholysis degree is 80%) in the 50mL conical flask, add distilled water, be mixed with the homogeneous transparent solution of 8%wt; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 20 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 10kV, and spinning head is 8cm apart from the distance of receiving pole, receives through 10h and obtains the uniform pure polyvinyl alcohol nano film of thickness; 3, then above-mentioned tunica fibrosa is put into the dry 24h of vacuum drying chamber, fully remove moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 210nm.
Contain the preparation of the polyvinyl alcohol nano film of NaCl (1.0wt%): 1, take by weighing 1.6g polyvinyl alcohol (alcoholysis degree is 80%) and put into the 50mL conical flask; Add distilled water; With the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; Then add 1.0% NaCl, continue dissolving and be stirred to homogeneous transparent; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus; Through conduit solution is incorporated into the constant temperature and humidity temperature device for spinning from syringe, maintains the temperature at 20 ℃ and relative humidity 30%, the spinning solution fltting speed is 0.001mm/s; Spinning voltage is 10kV, receives through 10h and obtains the nano fibrous membrane that thickness contains NaCl1.0wt% uniformly; 3, the film for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 308nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.0MPa; The average ultimate tensile strength that contains the polyvinyl alcohol nano film of 1.0wt%NaCl is: 4.4MPa.Pure polyvinyl alcohol nano film initial decomposition temperature (temperature of correspondence when referring to thermal weight loss 5%, down together) is 250 ℃; The initial decomposition temperature that contains the polyvinyl alcohol nano film of 1.0wt%NaCl is 299 ℃.Above result shows: the heat endurance and the mechanical property that contain the polyvinyl alcohol nano film of NaCl significantly improve.
Embodiment 2:
The preparation of pure polyvinyl alcohol nano film: 1, take by weighing 4.0g polyvinyl alcohol (alcoholysis degree is 99%) in the 50mL conical flask, add distilled water, be mixed with the homogeneous transparent solution of 20%wt; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 45kV, and spinning head is 15cm apart from the distance of receiving pole, receives through 5h and obtains the uniform pure polyvinyl alcohol nano film of thickness; 3, then above-mentioned tunica fibrosa is put into the dry 24h of vacuum drying chamber, fully remove moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 340nm.
Contain the preparation of the polyvinyl alcohol nano film of NaCl (0.001wt%): 1, take by weighing 4g polyvinyl alcohol (alcoholysis degree is 99%) and put into the 50mL conical flask; Add distilled water; With the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; The NaCl that then adds 0.001wt% continues dissolving and is stirred to homogeneous transparent; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 45kV, and spinning head is 15cm apart from the distance of receiving pole, receives through 5h and obtains the polyvinyl alcohol nano film that thickness contains NaCl0.001wt% uniformly.3, the film for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 450nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.8MPa; The average ultimate tensile strength that contains the polyvinyl alcohol nano film of 0.001wt%NaCl is: 4.3MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 270 ℃; The initial decomposition temperature that contains the polyvinyl alcohol nano film of 0.001wt%NaCl is 304 ℃.Above result shows: the heat endurance and the mechanical property that contain the polyvinyl alcohol nano film of NaCl significantly improve.
Embodiment 3:
The preparation of pure polyvinyl alcohol nano film: 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) in the 50mL conical flask, add distilled water, be mixed with the homogeneous transparent solution of 10%wt; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 50 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.005mm/s; Spinning voltage is 30kV, and spinning head is 25cm apart from the distance of receiving pole, receives through 8h and obtains the uniform pure polyvinyl alcohol nano film of thickness; 3, then above-mentioned tunica fibrosa is put into the dry 24h of vacuum drying chamber, fully remove moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 220nm.
Contain the preparation of the polyvinyl alcohol nano film of NaCl (3.0wt%): 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) and put into the 50mL conical flask; Add distilled water; With the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; Then add 3.0% NaCl, continue dissolving and be stirred to homogeneous transparent; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus; Through conduit solution is incorporated into the constant temperature and humidity temperature device for spinning from syringe, maintains the temperature at 30 ℃ and relative humidity 30%, the spinning solution fltting speed is 0.005mm/s; Spinning voltage is 30kV, receives through 8h and obtains the nano fibrous membrane that thickness contains NaCl3.0wt% uniformly; 3, the film for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 285nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.5MPa; The average ultimate tensile strength that contains the polyvinyl alcohol nano film of 3.0wt%NaCl is: 4.2MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 255 ℃; The initial decomposition temperature that contains the polyvinyl alcohol nano film of 3.0wt%NaCl is 297 ℃.Above result shows: the heat endurance and the mechanical property that contain the polyvinyl alcohol nano film of NaCl significantly improve.
Embodiment 4:
The preparation of pure polyvinyl alcohol nano film: 1, take by weighing 1.6g polyvinyl alcohol (alcoholysis degree is 80%) in the 50mL conical flask, add distilled water, be mixed with the homogeneous transparent solution of 8%wt; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, receives through 10h and obtains the uniform pure polyvinyl alcohol nano film of thickness; 3, then above-mentioned tunica fibrosa is put into the dry 24h of vacuum drying chamber, fully remove moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 218nm.
Contain Na
2CO
3The preparation of polyvinyl alcohol nano film (0.3wt%): 1, take by weighing 1.6g polyvinyl alcohol (alcoholysis degree is 80%) and put into the 50mL conical flask, add distilled water, with the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; The Na that then adds 0.3wt%
2CO
3, continue dissolving and be stirred to homogeneous transparent; 2, the solution with above-mentioned preparation adds in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, obtains thickness through 10h and contains Na uniformly
2CO
3The 0.3wt% nano fibrous membrane.3, the tunica fibrosa for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 250nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.3MPa; Contain 0.3wt%Na
2CO
3The average ultimate tensile strength of polyvinyl alcohol nano film be: 4.2MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 245 ℃; Contain 0.3wt% Na
2CO
3The initial decomposition temperature of polyvinyl alcohol nano film be 270 ℃.Above result shows: contain Na
2CO
3The heat endurance and the mechanical property of polyvinyl alcohol nano film significantly improve.
Embodiment 5:
The preparation of pure polyvinyl alcohol nano film: 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) in the 50mL conical flask, add distilled water, be mixed with the homogeneous transparent solution of 10%wt; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, receives through 8h and obtains the uniform pure polyvinyl alcohol nano film of thickness; 3, then above-mentioned tunica fibrosa is put into the dry 24h of vacuum drying chamber, fully remove moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 230nm.
Contain the preparation of the polyvinyl alcohol nano film of KCl (0.3wt%): 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) and put into the 50mL conical flask; Add distilled water; With the stirred in water bath heating 1h of above-mentioned solution, obtain the homogeneous transparent solution of polyvinyl alcohol then at 60 ℃; The KCl that then adds 0.3wt% continues dissolving and is stirred to homogeneous transparent; 2, the solution with above-mentioned preparation adds in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, receives through 8h and obtains the polyvinyl alcohol nano film that thickness contains KCl0.3wt% uniformly.3, the tunica fibrosa for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 280nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.5MPa; The average ultimate tensile strength that contains the polyvinyl alcohol nano film of 0.3wt%KCl is: 4.1MPa.Pure vinal film initial decomposition temperature is 255 ℃; The initial decomposition temperature that contains the polyvinyl alcohol nano film of 0.3wt% KCl is 282 ℃.Above result shows: the heat endurance and the mechanical property that contain the polyvinyl alcohol nano film of KCl significantly improve.
Embodiment 6:
The preparation of pure polyvinyl alcohol nano film: with embodiment 5
Contain Na
2SO
4The preparation of polyvinyl alcohol nano film (0.3wt%): 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) and put into the 50mL conical flask, add distilled water, with the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; The Na that then adds 0.3wt%
2SO
4, continue dissolving and be stirred to homogeneous transparent; 2, the solution with above-mentioned preparation joins in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, and process 8h reception obtains thickness and contains Na uniformly
2SO
4The polyvinyl alcohol nano film of 0.3wt%.3, the tunica fibrosa for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 330nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.5MPa; Contain 0.3wt%Na
2SO
4The average ultimate tensile strength of polyvinyl alcohol nano film be: 4.0MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 255 ℃; Contain 0.3wt% Na
2SO
4The initial decomposition temperature of polyvinyl alcohol nano film be 285 ℃.Above result shows: contain Na
2SO
4The heat endurance and the mechanical property of polyvinyl alcohol nano film significantly improve.
Embodiment 7:
The preparation of pure polyvinyl alcohol nano film: with embodiment 5
Contain NaHCO
3The preparation of polyvinyl alcohol nano film (0.3wt%): 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) and put into the 50mL conical flask, add distilled water, with the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; The NaHCO that then adds 0.3wt%
3, continue dissolving and be stirred to homogeneous transparent; 2, the solution with above-mentioned preparation adds in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, obtains thickness through 8h and contains NaHCO uniformly
3The 0.3wt% nano fibrous membrane.3, the tunica fibrosa for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 315nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.5MPa; Contain 0.3wt% NaHCO
3The average ultimate tensile strength of polyvinyl alcohol nano film be: 3.9MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 255 ℃; Contain 0.3wt% NaHCO
3The initial decomposition temperature of polyvinyl alcohol nano film be 258 ℃.Above result shows: contain NaHCO
3The heat endurance of polyvinyl alcohol nano film obviously do not improve, but mechanical property significantly improves.
Embodiment 8:
The preparation of pure polyvinyl alcohol nano film: with embodiment 5
Contain the preparation of the polyvinyl alcohol nano film of NaOH (0.3wt%): 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) and put into the 50mL conical flask; Add distilled water; With the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; The NaOH that then adds 0.3wt% continues dissolving and is stirred to homogeneous transparent; 2, the solution with above-mentioned preparation adds in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, obtains thickness through 8h and contains the NaOH0.3wt% nano fibrous membrane uniformly.3, the tunica fibrosa for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 308nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.5MPa; The average ultimate tensile strength that contains the polyvinyl alcohol nano film of 0.3wt% NaOH is: 3.8MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 255 ℃; The initial decomposition temperature that contains the polyvinyl alcohol nano film of 0.3wt% NaOH is 280 ℃.Above result shows: the heat endurance and the mechanical property that contain the polyvinyl alcohol nano film of NaOH significantly improve.
Embodiment 9:
The preparation of pure polyvinyl alcohol nano film: with embodiment 5
Contain H
3BO
3The preparation of polyvinyl alcohol nano film (0.3wt%): 1, take by weighing 2g polyvinyl alcohol (alcoholysis degree is 88%) and put into the 50mL conical flask, add distilled water, with the stirred in water bath heating 1h of above-mentioned solution, obtain homogeneous transparent solution then at 60 ℃; The H that then adds 0.3wt%
3BO
3, continue dissolving and be stirred to homogeneous transparent; 2, the solution with above-mentioned preparation adds in the 20mL syringe; Be fixed to then on the propeller of electrostatic spinning apparatus, solution be incorporated into the constant temperature and humidity device for spinning from syringe, maintain the temperature at 30 ℃ and relative humidity 30% through conduit; The spinning solution fltting speed is 0.001mm/s; Spinning voltage is 30kV, and spinning head is 15cm apart from the distance of receiving pole, obtains thickness through 8h and contains H uniformly
3BO
3The 0.3wt% nano fibrous membrane.3, the tunica fibrosa for preparing is put into dry 24h in the vacuum drying chamber, fully removes moisture, and put into drier and deposit subsequent use.Through fibre diameter statistics in the tunica fibrosa stereoscan photograph is learnt that the average diameter of this polyvinyl alcohol nano film is about 356nm.
Tunica fibrosa is carried out extension test and thermogravimetic analysis (TGA): test result shows that the average ultimate tensile strength of pure polyvinyl alcohol nano film is: 2.5MPa; Contain 0.3wt% H
3BO
3The average ultimate tensile strength of polyvinyl alcohol nano film be: 4.1MPa.Pure polyvinyl alcohol nano film initial decomposition temperature is 255 ℃; Contain 0.3wt% H
3BO
3The initial decomposition temperature of polyvinyl alcohol nano film be 290 ℃.Above result shows: contain H
3BO
3The heat endurance and the mechanical property of polyvinyl alcohol nano film significantly improve.