High-strength carbon nanofiber membrane and preparation method thereof

Abstract

The invention relates to a high-strength carbon nanofiber membrane and a preparation method thereof. The preparation method comprises an electrostatic spinning procedure and a pre-oxidation treatmentprocedure and further comprises a preheating treatment procedure located between the electrostatic spinning procedure and the pre-oxidation treatment procedure, the starting temperature of preheatingtreatment is room temperature, the heating rate is 1-5 DEG C / min, the terminal temperature is (T+a) DEG C, T = max {Tb, Tg}, Ta is the boiling point of a solvent for electrostatic spinning, Tg is theglass-transition temperature of the polymer for electrostatic spinning, a is -5-5, and the heat preservation time is 1-2 hours; and the breaking strength of the finally prepared high-strength carbon nanofiber membrane is 70-120 MPa. According to the preparation method of the high-strength carbon nanofiber membrane, solvent molecules entangled by disorderly-oriented molecular chains can be effectively removed, a large number of structural defects caused by subsequent solvent removal are avoided, meanwhile, fiber breakage is effectively reduced, the fiber breakage number is reduced to about onetenth of the original fiber breakage number, and the breaking strength of the finally prepared high-strength carbon nanofiber membrane is far higher than that in the prior art.

Description

technical field [0001] The invention belongs to the technical field of carbon nanofiber membranes, and relates to a high-strength carbon nanofiber membrane and a preparation method thereof. Background technique [0002] Carbon nanofibers with diameters in the range of submicron and nanometers in a continuous arrangement form, due to their good chemical resistance, ultra-high specific surface area, good thermal stability, excellent electrical conductivity, high stiffness and low density And other comprehensive properties, it shows great application potential in composite materials, supercapacitors, catalyst supports, solar cells, sensors and other fields. [0003] Carbon nanofibers can generally be prepared by the following two methods: chemical vapor deposition and electrospinning. Chemical vapor deposition, that is, the catalytic synthesis method, decomposes carbon precursors (usually hydrocarbons) with the help of metal catalyst particles, and then rearranges carbon atoms...

AI Technical Summary

Problems solved by technology

Chemical vapor deposition, that is, the catalytic synthesis method, decomposes carbon precursors (usually hydrocarbons) with the help of metal catalyst particles, and then rearranges carbon atoms into carbon substances. The reaction between carbon raw materials and catalyst particles generally occurs between Ar and H 2 However, the carbon nanofibers prepared by chemical vapor deposition are wavy, easy to entangle with each other, difficult to assemble and process, and the production rate is low and the equipment is expensive; Electrospinning technology Provides a direct and cost-effective method to fabricate submicron-scale continuous carbon fibers, so electrospinning is the most commonly used method for fabricating carbon nanofibers, and carbon nanofibers derived from electrospinning are continuous and relatively well-aligned, and the structure can control, ideal for strengthening, hardening and toughening polymers

[0004] However, in addition to the solvent evaporated under the action of high pressure, there are still some solvent residues in the fiber membrane collected by electrospinning.

The unevaporated solvent molecules remaining between the randomly oriented polymer chains will be volatilized instantly under the high temperature of the subsequent heat treatment. This violent volatilization will leave abundant structural defects (micropores), and at the same time due to the During the process, the stretching and orientation of the polymer chains are not uniform, and the polymer chains are entangled. It is easy to relax the macromolecular chains with the increase of the chain mobility in the traditional heat treatment process, which leads to the shrinkage of the fibers and is accompanied by a large area. Fiber fractures, which will affect the fracture strength of the final carbon nanofiber membrane

[0005] In order to solve the above problems, a series of studies have been carried out in the prior art. Patent CN200810126593.0 discloses a method and device for removing solvent in polyethylene fibers. The main steps are: a) extruding polyethylene fibers; b) extracting through step a ) solvent in polyethylene fibers, but it is mainly suitable for the situation where the residual amount of solvent is large, and has little effect on the trace solvent molecules coated by the entanglement of molecular chains in nanofibers; the paper "Optimization of stabilization conditions for electrospun polyacrylonitrile nanofibers." (Polymer Degradation and Stability, Volume 97, Issue 8, August 2012, Pages 1511-1519.) The optimal pre-oxidation conditions were obtained: under a constant load of 1kN, it was heated at a heating rate of 2°C / min from 30°C to Heat treatment at 280°C for 2 hours, however, it did not take effective measures for the removal of residual solvents and the fiber breakage did not improve

Images