Preparation of rubber nano fibre
Technical field: The invention relates to a method for preparing rubber nano-fiber. The prepared rubber nano-fiber can be used for biomedical, bactericidal, toughened plastics and other fields. Background technology: The electrostatic spinning technology in Formhals 1934 years. From the last century 80 in the especially in the last ten years (about 1995 year front and rear), in the development of nano-technology, electrostatic spinning re-attention, by using the technology, is very easy to pull the many polymer processing into different fiber structure, different scales (of sub-micron to nanometer) the superfine fiber. Utilizes the electrostatic spinning technology has successfully preparing polymer nano-fibers include polyamide (PA6, PA66), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polylactic acid (PLA), cellulose acetate (CA), polyurethane (PU), polycaprolactone (PCL) and many other polymer matrix. Chinese Patent "affinity acrylonitrile based copolymer superfine fiber film preparation method and application" (CN101185851 public number) acrylonitrile copolymer dissolved in a solvent, to carry out electrostatic spinning, the superfine fiber membrane affinity acrylonitrile copolymer, fiber diameter is 80-800nm. United States Patent "Electrospunelectroactive polymers" (public number 20060057377) of the polymer with a polar group, such as polyamide, polyurethane, polyacrylic acid, dissolved in a solvent, to carry out electrostatic spinning, the prepared with conductive active polymer nano-fiber, fiber diameter is 10-10000nm. The current use of electrostatic spinning method of the co-polymer nano-fiber is substantially normal temperature is in the glassy or crystalline polymer matrix, because these polymers under the electrostatic induction is the fiber after stretching and, rapid volatilization of the solvent in the process in the process of cooling or rapid cooling can be rapidly re-transformed into the glassy or crystalline state and the fixed-down, the fiber is not deformed, easy to control the continuity and stability of the spinning process. However, the polymer of the invention is in a high at room temperature, such as electrostatic spinning preparation method for preparing rubber nano-fiber, there are very few literature reports or patents. The main reason is that, more molecular conformation of rubber, the glass transition temperature of the 0 [...] the following, not crystalline, has high elasticity, activities chain place strong ability of large molecules, molecule chain relaxation time is short, caused by the spinning 3 is difficult to solve the problem : (1) in the spinning process, rapid volatilization of the solvent at the same time, due to the high elasticity rubber molecule fiber deformation quick reply, the disturbance in the vicinity of a spinning nozzle, it is very difficult to control the continuity and stability of the spinning, the fiber surface has also often been beaded ; (2) highly stretched rubber fiber quick response because of the high elastic deformation, causing a single fiber is not continuous, or even broken ; (3) the fiber diameter is relatively coarse (1 the above m), diameter distribution is difficult to control ; (4) is the most difficult to overcome in high carrying the uncross-linked rubber fiber shape under the action of gravity changes very quickly, especially in fiber lapped melts and is easy to occur, result in fibers packing together may form a thin film, it is difficult to maintain the appearance of the fiber. Literature [Polymeric Nanofibers, American Chemical Society, Washington, DC, 2005] reported that carbon black filled butyl rubber solution of the electrostatic spinning, found that with the increase in the amount of carbon black, the spinnability of the butyl rubber solution, the fiber diameter is reduced, the dimensional stability is increased. However, most of the fibers have a diameter of butyl rubber in a few micro-meters, but also because there is no rapid cross-linked, often melt and film-forming. Content of the invention The purpose of this invention is to provide a method for preparing rubber nano-fiber. The adoption of the coaxial electrostatic spinning method, in order to contain unsaturated carbon-carbon double bond of the rubber solution as the core layer solution, water-soluble polymer solution as shell solution, after exerting high-voltage electrostatic coaxial electrostatic spinning make. Rubber solution is added inorganic salt electrolyte and nanometer silica, improved electrostatic spinnability of the rubber solution; by means of coaxial electrostatic spins when at the same time outer polymer fiber space limit in order to reduce deformation of the elastic recovery of the rubber molecule, delaying fiber deformation; electrospining front, the rubber solution is cross-linking agent added in a proper amount, the electrostatic spinning of the fiber at the same time in-situ rapid crosslinking, the rubber molecules to rapidly form a three-dimensional cross-linked network structure, the appearance of the device, it is difficult to solve the elastic rubber spins high continuous and stabilized, the fiber diameter is coarse, problem of poor shape stability, preparing the cross-linked rubber nano-fiber. The invention provides a method for preparing rubber nano-fiber, the adoption of the coaxial electrostatic spinning method, to rubber solution as the core layer solution, water-soluble polymer solution as shell solution, after exerting high-voltage electrostatic coaxial electrostatic spinning make, the specific preparation conditions and steps are as follows: (1) will contain unsaturated carbon-carbon double bond of the rubber, inorganic salt electrolyte dissolved in volatile organic solvent at room temperature, with the addition of modified reinforcing filler compounded into a rubber solution and stirred, rubber quality of solution concentration is 5%-20%, rubber, inorganic salt electrolyte and modified reinforcing filler mass ratio of the 100 [...] 0.5-25 the [...] 5-30; electrostatic prespinning, the rubber solution is added in 0.5-10 parts by mass of the cross-linking agent; (2) the room temperature has a glassy or crystalline can be water-soluble polymer is dissolved in organic solvent, stirring to be completely dissolved, to make the mass concentration is 5%-20% solution of the shell; (3) set the spinneret and receiving plate 8-25cm, adjusting the velocity of flow of the core layer solution is 0.5-2.0 ml/h, spinneret diameter is 0.5-1.0 mm, the velocity of flow of the shell layer solution is 0.5-3.0 ml/h, spinneret with a diameter of 1.0-1.5 mm; after flowing out to be stable, applying electrostatic voltage is 10-30kV, coaxial electrospining (as shown in Figure 1 is shown device), rubber/collected water-soluble polymer composite nano-fiber, composite fiber to the rubber phase 20-50 the in situ under the lower temperature of [...] fast after cross-linking, using de-ionized water to dissolve and remove a water-soluble polymer in the composite fiber of the outer layer, after drying at room temperature to obtain rubber nano-fiber. Containing the unsaturated carbon-carbon double bond of the rubber can be made of butadiene rubber, butyl rubber, silicon rubber or nitrile rubber, preferably butyl rubber or nitrile rubber. The the room temperature assumes glassy or crystalline water-soluble polymer can be made of polyvinyl-pyrrolidone, polyethylene oxide, or polyvinyl alcohol. In the coaxial electrostatic spinning process, the fiber blanket polymer molecule, rapid volatilization of the solvent in the process in the process of cooling or rapid cooling can be rapidly re-transformed into the glassy or crystalline state and the fixed-down, so that the fiber is not deformed. At the same time, by means of a shell layer nano-fiber space limit, can reduce deformation of the layer of rubber fiber, improved electrostatic spinnability of the rubber. Moreover, shell fiber as the water-soluble polymer, after dissolving can be through the use of de-ionized water, conveniently and quickly remove, does not affect the appearance and the rubber fiber core size stability. The inorganic salt electrolyte can choose the NaCl, AgNO3 or CaCl2 strong electrolyte, such as, the majority of the rubber is a non-polar, low conductivity solution, the electrostatic drawing force small, not conducive to the electrostatic spinning, by adding electrolyte in order to improve the conductivity of the rubber solution, to improve the spinnability of the rubber solution. The modified reinforcing filler for rubber commonly used in the field of double bond-containing silane coupling agent modified nanometer silicon dioxide, nano-silicon dioxide can be the precipitation method or vapor phase process silica. Modified method is a traditional dry modified, the invention adopts the modified agent is a vinyl ethoxy silane, after dilution with ethanol, and white carbon black is uniformly mixed in a high speed stirrer, wherein the vinyl ethoxy silane and ethanol, the mass ratio of the white carbon black the 3 [...] the 10 [...] 100, then the 120 [...] drying 2 hours. The rubber solution used for preparing the temperature of the volatile organic solvent may be tetrahydrofuran, dichloromethane, chloroform, acetone or N, N-dimethyl formamide. The water-soluble polymer is used for preparing the organic solvent can be made of tetrahydrofuran, ethanol or N, N-dimethyl formamide. The cross-linking agent is a two-component mixture, one of the component is that each molecule at least two Si-containing organopolysiloxane of a hydrogen atom (such as molecular chain both ends are trimethyl silyl oxygen radical sealed end methyl hydrogenated polysiloxane, the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end of dimethyl siloxane-methyl hydrogenated siloxane copolymer), another group of divided into platinum is the base catalyst, this invention adopts the alcohol solution of chloroplatinic acid, platinum metal content in the catalyst is 1 PPM -10000 PPM, organopolysiloxane and the mass ratio of the catalyst platinum is the base the 1 [...] the 3-4 [...] 1. Because the cross-linking agent is added in an amount of platinum metal catalyst, can make the rubber fibers at a relatively low temperature in-situ rapid crosslinking, the rubber molecules to rapidly form a three-dimensional cross-linked network structure, the appearance of the device. The invention selects the electrostatic spinning process parameters: the velocity of flow of the core layer solution is 0.5-2.0 ml/h, shell the velocity of flow of the solution is 0.5-3.0 ml/h, flow rate is too large, the spray nozzle is is not timely stretched droplet volume is relatively large, because the solvent volatilizes and coagulate, nozzle will be blocked, flow rate is too small, fiber collecting speed is slow, low yield. Spinneret diameter preferably 0.5-1.5 mm, the diameter of the spinneret is too small, the polymer solution is easy to block, large diameter extrusion, to produce drip flows out. Receiving distance preferably 8-25cm, receiving distance is too large, the fiber reaches the collecting plate the former solvent has been fully volatilized, fiber damage because of excessive stretching topography, accept the distance is too small, since the fiber reaches the collecting plate, the solvent did not sufficiently volatile, more residual solvent, will also damage the appearance of the fiber. Voltage preferably 10-30KV, voltage is too large, highly stretched rubber fiber because the elastic deformation quickly return, single fiber rupture, causing spinning is not continuous, the voltage is too small, the rubber solution because of low conductivity, the stretching force is small, the fiber has not been fully stretched, a thicker diameter, is not conducive to electrostatic spinning. The preparation method of this invention is simple, spinning continuity and stability is good, but also the preparation of stable topography rubber fiber, can solve the electrostatic spins high elastic rubber is difficult to be continuous and stabilization, fiber diameter of coarse, problem of poor stability of shape. This kind of rubber nano-fiber is expected to be in the biomedical, bactericidal, toughened plastics, and the like are widely applied in the field. The Figure illustrates: Figure 1 is a schematic diagram of the coaxial electrostatic spinning device. In the Figure, 1-core layer solution, 2-high-voltage power supply, 3-shell solution, 4-coaxial nozzle, 5-mixed jet, 6-collecting device, 7-cork. Specific embodiment: The invention will be more detailed description of the embodiment, the embodiment, however, does not constitute a limitation of this invention. Embodiment 1: the 1g (100 parts) silicon rubber, 0.25gNaCl (25 parts) and 0.3g (30 parts) silane coupling agent modified of the vapor phase process white carbon black underwaterly to 10g, methylene chloride, formulated into a rubber solution and stirred, to obtain core layer solution, electrostatic spinning the former, is added in the core layer solution 0.005g (0.5 parts) cross-linking agent (cross-linking agent of organic polysiloxane A is of the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end methyl hydrogenated polysiloxane, chloroplatinic acid solution B in platinum metal content is 10000 PPM, A, B two-component mass ratio of the 1 [...] 1); the 1.5g polyvinylpyrrolidone dissolved in the 10g in ethanol, stir to get shell solution; coaxial electrospining, setting a spinneret and receiving plate distance is 15 cm, the core layer to the velocity of flow of the solution 1.0 ml/h, spinneret with the diameter of 0.5 mm, the shell the velocity of flow of the solution to 2.0 ml/h, spinneret diameter is 1.0 mm, the electrostatic voltage is 15KV, silicone rubber/polyvinyl pyrrolidone collected composite nano fiber; to be composite nano fiber in 40 the fast after cross-linking in situ under [...] , the composite nano-fiber impregnated in the deionized water to remove the blanket fiber, is obtained after drying at room temperature silicon rubber nano-fiber. Embodiment 2: the 1g butyl rubber (100 parts), 0.05gAgNO3 (5 parts) and 0.05g (5 parts) silane coupling agent modified of the vapor phase process white carbon black underwaterly to 10g in tetrahydrofuran, formulated into a rubber solution and stirred, to obtain core layer solution, electrostatic spinning the former, is added in the core layer solution 0.1g (10 parts) cross-linking agent (cross-linking agent of organic polysiloxane A is of the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end methyl hydrogenated polysiloxane, chloroplatinic acid solution B in platinum metal content is 100 PPM, A, B two-component mass ratio of the 1 [...] 2); the 1.2g polyethylene oxide dissolved in the 10g in ethanol, stir to get shell solution; coaxial electrospining, spinneret and the receiving plate is set to 20 cm, core layer the velocity of flow of the solution is 0.8 ml/h, spinneret diameter is 0.6 mm, the velocity of flow of the shell layer solution is 1.2 ml/h, spinneret diameter is 1.2 mm, the electrostatic voltage is 20KV, butyl rubber/collected polyethylene oxide composite nano-fiber; to be composite nano-fiber in the fraction of 25 the fast after cross-linking in situ under [...] , the composite nano-fiber impregnated in the deionized water to remove the blanket fiber, room temperature drying butyl rubber nano-fiber. Embodiment 3: the 1g (100 parts) polybutadiene rubber, 0.2gAgNO3 (20 parts) and 0.1g (10 parts) silane coupling agent-modified precipitated silica underwaterly to 8g in tetrahydrofuran, formulated into a rubber solution and stirred, to obtain core layer solution, electrostatic spinning the former, is added in the core layer solution 0.03g (3 parts) cross-linking agent (cross-linking agent of organic polysiloxane A is of the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end of dimethyl siloxane-methyl hydrogenated siloxane copolymer, chloroplatinic acid solution B in platinum metal content is 3000 PPM, A, B two-component mass ratio of the 1 [...] 3); the 1.0g polyvinyl alcohol dissolved in the 10g in ethanol, stir to get shell solution; coaxial electrospining, spinneret and the receiving plate is set to 15 cm, the core solution flow rate is 1.5 ml/h, spinneret diameter is 1.0 mm, the shell the velocity of flow of the solution to 3.0 ml/h, spinneret diameter is 1.5 mm, the electrostatic voltage is 18KV, butadiene rubber/polyvinyl alcohol collected composite nano fiber; to be composite nano-fiber in the fraction of the 30 in situ under [...] after rapidly crosslinked, the composite nano-fiber impregnated in the deionized water to remove the blanket fiber, after drying at room temperature to obtain butadiene rubber nano-fiber. Embodiment 4: the 1g nitrile rubber (100 parts), 0.20g (20 parts) CaCl2 and 0.15g (15 parts) silane coupling agent-modified precipitated silica underwaterly to 12g chcl in, preparation into a rubber solution and stirred, to obtain core layer solution, electrostatic spinning the former, is added in the core layer solution 0.08g (8 parts) cross-linking agent (cross-linking agent of organic polysiloxane A is of the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end of dimethyl siloxane-methyl hydrogenated siloxane copolymer, chloroplatinic acid solution B in platinum metal content is 1000 PPM, A, B two-component mass ratio of the 3 [...] 1); the 1.0g polyvinylpyrrolidone dissolved in the 12g in ethanol, stir to get shell solution; coaxial electrospining, spinneret and the receiving plate is set to 20 cm, the core layer to the velocity of flow of the solution 0.6 ml/h, spinneret with a diameter of 0.8 mm, sheath solution for the flow rate of 1.2 ml/h, spinneret diameter is 1.2 mm, the electrostatic voltage is 25KV, acrylonitrile-butadiene rubber/polyvinyl pyrrolidone collected composite nano fiber; to be composite nano-fiber in the fraction of 45 the fast after cross-linking in situ under [...] , the composite nano-fiber impregnated in the deionized water to remove the blanket fiber, after drying at room temperature to obtain nitrile rubber nano-fiber. Embodiment 5: the 1g (100 parts) silicon rubber, 0.16g CaCl2 (16 parts) and 0.10g (10 parts) silane coupling agent modified of the vapor phase process white carbon black underwaterly to 8g, methylene chloride, formulated into a rubber solution and stirred, to obtain core layer solution, electrostatic spinning the former, is added in the core layer solution 0.08g (8 parts) cross-linking agent (cross-linking agent of organic polysiloxane A is of the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end of dimethyl siloxane-methyl hydrogenated siloxane copolymer, chloroplatinic acid solution B in platinum metal content is 5000 PPM, A, B two-component mass ratio of the 2 [...] 1); the 1.0g polyvinylpyrrolidone dissolved in 11g in ethanol, stir to get shell solution; coaxial electrospining, setting a spinneret and receiving plate distance is 18 cm, the core layer to the velocity of flow of the solution 1.2 ml/h, spinneret with a diameter of 0.7 mm, the velocity of flow of the shell layer solution to 2.2 ml/h, spinneret diameter is 1.5 mm, the electrostatic voltage is 30KV, silicone rubber/polyvinyl pyrrolidone collected composite nano fiber; to be composite nano fiber in 45 the fast after cross-linking in situ under [...] , the composite nano-fiber impregnated in the deionized water to remove the blanket fiber, is obtained after drying at room temperature silicon rubber nano-fiber. Embodiment 6: the 1g (100 parts) butyl rubber, 0.15gNaCl (15 parts) and 0.20g (20 parts) silane coupling agent modified of the vapor phase process white carbon black underwaterly to 9g in tetrahydrofuran, formulated into a rubber solution and stirred, to obtain core layer solution, electrostatic spinning the former, is added in the core layer solution 0.06g (6 parts) cross-linking agent (cross-linking agent of organic polysiloxane A is of the molecular chains of the two ends are trimethyl silyl oxygen radical sealed end methyl hydrogenated polysiloxane, chloroplatinic acid solution B in platinum metal content is 3000 PPM, A, B two-component mass ratio of the 1 [...] 2); the 1.0g polyethylene oxide dissolved in 13g in ethanol, stir to get shell solution; coaxial electrospining, spinneret and the receiving plate is set to 22 cm, core layer the velocity of flow of the solution is 0.8 ml/h, spinneret diameter is 0.6 mm, the velocity of flow of the shell layer solution is 1.2 ml/h, spinneret diameter is 1.2 mm, the electrostatic voltage is 20KV, butyl rubber/collected polyethylene oxide composite nano-fiber; to be composite nano-fiber in the fraction of 50 the in situ under [...] after rapidly crosslinked, the composite nano-fiber impregnated in the deionized water to remove the blanket fiber, after drying at room temperature shall be butyl rubber nano-fiber. The embodiment of the invention 1-embodiment 6 continuous spinning process, the fiber has a diameter of several tens of nanometers to 1 micron, sedo for a period of time can still maintain good fiber topography. The ratio 1: the 1g (100 parts) silicon rubber dissolved in the 10g, methylene chloride, stir preparation into a rubber solution, a spinneret with the diameter of 0.5 mm, the pack and the receiving plate is set to 20 cm, solution flow rate is 0.8 ml/h, electrostatic voltage is 17KV. Electrostatic spinning is not continuous, the silicone rubber fiber collected quickly collapse and melting. The ratio 2: the 1g (100 parts) butyl rubber and 0.05g (5 parts) silane coupling agent modified of the vapor phase process white carbon black underwaterly to 10g in tetrahydrofuran, stir preparation into a rubber solution, spinneret and the receiving plate is set to 22 cm, spinneret with a diameter of 0.7 mm, the flow speed of the solution of 0.6 ml/h, electrostatic voltage is 20KV. Electrostatic spinning comparative continuous, the butyl rubber fiber collected a thicker diameter, sedo a period of time for melting and collapsing quickly after film forming. The invention relates to a method of preparing rubber nanometer fibers. The method adopts a coaxial electrostatic spinning method which uses a rubber as a sandwich layer solution and a water-soluble polymer solution as a casing solution, exerts high-pressure static electricity and then carries out coaxial electrostatic spinning. The preparation method is simple, has good spinning continuity and stability and stable figures of the prepared rubber fibers and is widely applicable to the fields of biomedicine, antibacterium, sterilization, toughened plastics, and the like. 1. A method for preparing rubber nano-fiber, the adoption of the coaxial electrostatic spinning method, to rubber solution as the core layer solution, water-soluble polymer solution as shell solution, after exerting high-voltage electrostatic coaxial electrostatic spinning make, the specific preparation conditions and steps are as follows: (1) will contain unsaturated carbon-carbon double bond of the rubber, inorganic salt electrolyte dissolved in volatile organic solvent at room temperature, with the addition of modified reinforcing filler compounded into a rubber solution and stirred, the mass percentage of the rubber concentration of 5%-20%, rubber, inorganic salt electrolyte and modified reinforcing filler mass ratio of the 100 [...] 0.5-25 the [...] 5-30; electrostatic prespinning, the rubber solution is added in 0.5-10 parts by mass of the cross-linking agent; (2) the room temperature has a glassy or crystalline can be water-soluble polymer is dissolved in organic solvent, stirring to be completely dissolved, to make the mass concentration is 5%-20% solution of the shell; (3) set the spinneret and receiving plate 8-25cm, adjusting the velocity of flow of the core layer solution is 0.5-2.0 ml/h, spinneret diameter is 0.5-1.0 mm, the velocity of flow of the shell layer solution is 0.5-3.0 ml/h, spinneret with a diameter of 1.0-1.5 mm; after flowing out to be stable, applying electrostatic voltage is 10-30kV, coaxial electrospining, rubber/collected water-soluble polymer composite nano-fiber, composite fiber to the rubber phase 20-50 the in situ under the lower temperature of [...] fast after cross-linking, using de-ionized water to dissolve and remove a water-soluble polymer in the composite fiber of the outer layer, after drying at room temperature to obtain rubber nano-fiber. 2. Rubber of the method for preparing nanometer fiber according to Claim 1, which is characterized in that: said containing unsaturated carbon-carbon double bond of the rubber is a butadiene rubber, butyl rubber, silicon rubber or nitrile rubber. 3. Method for preparing rubber nano fiber according to Claim 1, which is characterized in that: the water-soluble polymer is polyvinyl pyrrolidone, polyethylene oxide, or polyvinyl alcohol. 4. Rubber of the method for preparing nanometer fiber according to Claim 1, which is characterized in that: the inorganic salt electrolyte is NaCl, AgNO3 or CaCl2. 5. Rubber of the method for preparing nanometer fiber according to Claim 1, which is characterized in that: the modified reinforcing filler containing double bond of nano silicon dioxide which is modified with silane coupling agent. 6. Rubber of the method for preparing nanometer fiber according to Claim 1, which is characterized in that: the rubber solution used for preparing the organic solvent is tetrahydrofuran, dichloromethane, chloroform, acetone or N, N-dimethyl formamide. 7. Rubber of the method for preparing nanometer fiber according to Claim 1, which is characterized in that: the water-soluble polymer is used for preparing the shell layer solution of the organic solvent is tetrahydrofuran, ethanol or N, N-dimethyl formamide. 8. Rubber of the method for preparing nanometer fiber according to Claim 1, which is characterized in that: the cross-linking agent is a two-component mixture, one of the component is both ends of the molecular chains is trimethyl silyl oxygen radical sealed end methyl hydrogenated polysiloxane or both ends of the molecular chains is trimethyl silyl oxygen radical sealed end of dimethyl siloxane-methyl hydrogenated siloxane copolymer, another group of divided into platinum is the base catalyst, a platinum metal content in the catalyst 1 PPM -10000 PPM, organopolysiloxane and the mass ratio of the catalyst platinum is the base the 1 [...] the 3-4 [...] 1.