Preparation And Properties Of Polyacrylonitrile Carbon Fiber Paper By High Efficiency Centrifugal Spinning

As a high-performance fiber,polyacrylonitrile（PAN）-based carbon fiber is widely used in various fields because of its excellent comprehensive properties.Carbon fiber paper is a high-performance composite paper-based material made of carbon fiber and used in fuel cells and supercapacitors.At present,due to the technical blockade,the development of domestic carbon fiber paper is not mature.So,it is urgent to develop high-performance carbon fiber paper that can be industrially produced.As a new type of spinning technology,centrifugal spinning technology is safe and stable,with high production efficiency.In this project,we intend to develop a centrifugal spinning equipment suitable for industrial production,through which PAN fiber is prepared.Then,after hot pressed,pre-oxidized and carbonized,PAN carbon fiber paper is obtained.By studying the traditional planar collection centrifugal spinning equipment,a planar collection centrifugal spinning equipment that can carry out high-efficiency large-scale production was built in view of its inability to produce continuously and collect unevenly.Design a method of connecting the feeding system,multi-spinning tank working at the same time,traversing reciprocating,and the electronic control system to control the whole process to achieve all-round coverage spinning.This centrifugal spinning equipment includes:feeding system,multi-spinning can spinning system,collection system and electronic control system.Then,using PAN as raw material,the centrifugal spinning equipment was verified,and it was proved that it could carry out high-efficiency large-scale continuous spinning,produce fiber felt uniformly,solve the shortcomings of uneven collection and inability to produce continuously in the traditional planar collection centrifugal spinning type,and then prepare PAN carbon fiber paper.Using N,N-dimethylformamide（DMF）as the solvent to prepare PAN spinning stock solution,PAN fiber felt was produced by high-efficiency centrifugal spinning equipment,and then PAN fiber paper（PFP）was obtained by hot pressing.The results show that PFP has a complex and dense three-dimensional network structure,the surface of a single fiber is smooth and uniform thickness.The fiber paper（PFP-6）with PAN content of 22.5%has the largest diameter of 4.660μm,and its infrared characteristic peak and X-ray diffraction peak conform to typical PAN characteristic peak.As the mass fraction and molecular weight increase,the diameter and crystallinity of the fiber increase,and the infrared absorption peak intensity varies.In addition,PFP-6 has excellent thermal stability,which is significantly enhanced compared to other samples.Therefore,the high average molecular weight PAN has an enhanced effect on the thermal stability of fiber paper prepared by centrifugal spinning.With PFP as raw material,PAN carbon fiber paper（PCFP）is prepared by pre-oxidation and carbonization.The microscopic morphology of PCFP is similar to that of PFP.The fiber diameter is significantly reduced due to carbonization,and the microstructure proves the formation of carbon fiber.The average water static contact angle of PCFP is 140°,which shows it is a kind of hydrophobic material.With the increase of PAN mass fraction and molecular weight,the conductivity gradually increases.When the carbonization temperature is 1200°C,the conductivity of PCFP-6-1200 reaches 43.3 s·cm^-1.When the carbonization temperature is reduced to 800°C,the sample is almost non-conductive.The electrochemical performance of PCFP-6-1200 shows that it can be used as a reversible electrode with a maximum capacitance of 841 m F·cm^-2.This shows that the high carbonization temperature has an enhanced effect on the performance of carbon fiber paper and can be used as an electrode material.In summary,the carbon fiber paper prepared by this method has the characteristics of good electrical conductivity,high capacitance and strong hydrophobicity,which provides a new scheme for the industrialization of centrifugal spinning technology and the production and manufacturing of carbon fiber paper.