Study On Rheological Behavior Of PAN/DMSO Solution And Dry-jet Wet-spinning Spinability

Carbon fiber (CF) has serials of excellent performance such ashigh strength, high modulus, anti-high temperature, anti-erosion and soon. So it had rapid development in recent decades. The high strength andhigh modulus performance of CF lies on the kind and quality of precursor,technology of pre-oxidation and carbonization and other factors.Precursor is one of the main factors that affect CF's performance. Highquality polyacrylonitrile (PAN) precursor is perfect row material toproduce high performance CF. But by now domestic organizations havenot done enough work on high performance CF, especially on highperformance PAN precursor. And the qualityof PAN precursor has beenthe choke point to develop high performance CF in our country. Theeffect of spinning and secondary stage stretching on fiber's structure andproperties was studied in this thesis, using dime thylsulfoxide (DMSO) assolvent and by dry-jet wet-spinning technology. This is the foundation toproduce high perfomiance PAN precursor.In preface of this thesis, the development history and current status of CF, the quality parameters of high performance PAN precursor and the factors affecting spinning process and precursor's quality, etc.were expatiated, which are the theoretical foundation of experiment.To improve the spinnability of spinning dope, rheological behavior of PAN/DMSO solutions was studied with Germanic HAAKE Company's RS150L type cone-andplaterheometer, and theoretical analysis was done. The research results showed that at lower shear velocity, the rheological curves descend along with the raise of temperature, decrease of solution's concentration and decrease of the molecular, and he critical shear velocity transformed from Newtonian section to non-Newtonian section raised. At higher velocity, the solutions at higher temperature and with lower concentration and lower molecular weight have higher viscosity. At certain concentration and shear velocity, the viscosity of PAN/DMSO solutions descends by index relation with increasing of temperature, i.e. it accord with Arrhenius' equation. With increase of shear velocity, decrease of concentration and molecular weight, the viscous flow activation energy of PAN/DMSO solution decreases. PAN/DMSO solution's non-Newtonian index n