4results about How to "Spinning process is stable" patented technology

The present invention provides a polylactic acid fiber spinneret with a double concave-convex special-shaped cross section, and relates to the technical field of polylactic acid fiber spinning. The polylactic acid fiber spinneret with a double concave-convex special-shaped cross section comprises an upper plate, a lower plate, a seat ring, a liquid guide cavity, a liquid guide groove, and a liquid guide hole. The present invention provides multiple groups of inserts with spinnerets, so that multiple groups of spinnerets are used in combination, which effectively solves the problem of processing difficulties after increasing the length of the spinnerets, and the detachable connection simplifies the work of cleaning the spinnerets. A sink is provided on the lower wall of the lower plate, and the weight of the spinneret is greatly reduced by hollowing out. Multiple groups of spinnerets are arranged in increasing order from top to bottom, and a nano alloy ion layer is provided on the inner wall of the spinneret to increase the smoothness, which can release part of the elastic potential energy of the polylactic acid melt to a certain extent, reduce the expansion ratio of the primary silk, and maintain the stability of spinning. The nano alloy ion layer also plays an anti-corrosion role.

An adjustable electrostatic spinning device comprises a receiving table, a drawer type conducting layer is slidably connected into the receiving table, a receiving container corresponding to the conducting layer is arranged above the receiving table, and a rack is installed on one side of the receiving container and located above the receiving table. The tail end of the machine frame is connected with a needle head support located above the interior of the receiving container, a needle head is installed on the needle head support and connected with the high-voltage end of a high-voltage power source, and the conducting layer is externally connected to a ground wire of the high-voltage power source to form a closed loop; through space design, electrostatic spinning can be carried out in a solution environment, a needle head is arranged in a solution of a receiving container, spinning in the solution environment is achieved under the action of electrostatic field force, and it is guaranteed that fibers are stably and fully stretched in the solution environment; the device can effectively improve the splashing condition on the surface of the needle fiber, ensures that the position of the needle can be adjusted at multiple angles, and has the characteristic of concentrated and stable spinning.

The invention discloses a method for improving the compactness of a polyacrylonitrile precursor. According to the method, the compactness of the polyacrylonitrile precursor is improved by controlling the process conditions that a polyacrylonitrile spinning stock solution is extruded through a spinneret plate, drafted through an air layer and then enters a coagulating bath, the length-diameter ratio of the spinneret plate is 3, the temperature of the coagulating bath is 18-20 DEG C, and the DMSO concentration in the coagulating bath is 35 wt.%-45 wt.%. According to the method, the compactness of the precursor and the stability in the spinning process are effectively improved, the high-performance precursor is produced, the volume density of the prepared polyacrylonitrile precursor is larger than or equal to 1.18 g / cm < 3 >, the swelling degree is smaller than or equal to 130%, and therefore the performance of the carbon fiber is improved.

This invention belongs to the field of inorganic nanofiber materials technology, specifically relating to a highly flexible boron nanofiber (BN) ceramic nanofiber and its preparation method. Using boric acid and melamine as main raw materials, this invention prepares the nanofiber through a complexation reaction, solution preparation, electrospinning, and heat treatment. The raw materials are inexpensive, the process is simple, and it is easy to scale up production. By heating the electrospinning needle at 90-120℃, the viscosity of the precursor needle tip is reduced, preventing premature crystallization of the complex and completely solving the needle clogging problem, ensuring continuous and stable spinning, and improving spinning efficiency and fiber quality. The resulting BN nanofibers are continuous, have uniform diameter, and a smooth surface. The controllable transformation from amorphous BN to highly crystalline hexagonal boron nitride can be achieved by adjusting the heat treatment temperature. The amorphous BN nanofiber felt has extremely low thermal conductivity (≤0.029 W / (m·K)) and excellent compression resilience, making it suitable as a reinforcement for composite materials or directly applicable in high-temperature filtration, high-efficiency heat insulation, and catalyst carriers.