A Brief Introduction To Electrospinning

　　 Electrospinning Electrospinning, also known as electrospinning, is a process that uses polymer solution or melt to form jet flow under strong electric field for spinning. In recent years, electrospinning, as a new processing method that can produce ultra-fine fibers, has attracted extensive attention. Theoretically, any soluble or molten polymer material can conduct electricity spinning Processing. At present, more than 30 kinds of polymers have been successfully electrospinned in the world, including natural polymers such as DNA, collagen, silk protein, and synthetic polymers such as polyoxyethylene, polyacrylonitrile, polylactic acid, polyimide, nylon, polyvinyl alcohol, polycaprolactone, polyurethane, etc.

principle

During the electrospinning process, the injection device is filled with charged polymer solution or molten liquid. Under the action of an external electric field, the polymer droplets kept at the nozzle by the surface tension will gather charges on the surface under the induction of the electric field, and will be subject to an electric force opposite to the direction of the surface tension. When the electric field gradually increases, the droplets at the nozzle are elongated from spherical to conical, forming the so-called Taylor cone. When the electric field strength increases to a critical value, the electric field force will overcome the surface tension of the liquid and eject from the Taylor cone. The jet flow vibrates and becomes unstable under the action of high electric field, resulting in irregular spiral motion with high frequency. In the high-speed oscillation, the jet stream is rapidly thinned, and the solvent is also rapidly volatilized, eventually forming fibers with a diameter of nm, which are scattered on the collection device in a random manner to form non-woven fabrics.

electric Spinning equipment Industrialization status

In September 2003, the Czech University of Liberez cooperated with Elmarco to develop the world's first nano fiber spinning machine - nano spider. Nanospiders eliminate the spinneret in traditional electrospinning and replace it with a cylinder. The cylinder is partially immersed in the polymer solution, constantly rotates and forms numerous Taylor cones under the action of electric field. Taylor cones spray jet streams to form nanofibers, which increases the production efficiency from 011~1g/h of traditional single spinneret spinning machine to 1~5g/min, and can produce large-area non-woven fabrics with a width of more than 1m, It has laid a good foundation for large-scale industrial production of electrospun nanofibers in the future.

At present, there are about dozens of large companies and enterprises participating in the development of electrospinning products worldwide, such as Elmarco, Freudenberg, Donalson, Japan, STARinc. and eSpin. At present, the research and technology of electrospinning in China is at the world's advanced level, but there has been no large-scale industrial production. Among them, HY-1 type electrospinning equipment produced by Yongqing Huayuan Biomaterials Technology Co., Ltd. is in sharp contrast with neu type electrospinning equipment produced by Kado Co., Ltd. in Japan. HY-1 electrospinning equipment integrates the distributed functions of traditional mechanical operation with CNC mechanical devices. In the process of spinning, the liquid flow rate is precisely controlled by the control system of injection and reciprocating translation. It has realized the characteristics of simple operation, repeatability, small-scale production and batch production. At present, the company has developed the first large-scale nanofiber spinning machine - Sing, which can produce large-area non-woven fabrics with a width of 1m, and the yield is about 100m/min. This means that domestic electrospinning nano fibre Large scale industrial production has begun.