Method for hybrid dry-jet gel spinning and fiber produced by that method

Abstract

A method of spinning a polyacrylonitrile PAN-based precursor fiber comprises extruding a spinning solution of ultra-high molecular weight polyacrylonitrile polymer through a multi-filament spinnerette where the solution has a viscosity of between about 100 and about 300 Pa-sec (at a shear rate of 1 l/sec) at a dope extrusion temperature of between about 20° C. and about 26° C., producing a fiber having a diameter of between about 4 and about 10 micron, a tensile strength of between about 500 and about 1100 MPa, and an elastic modulus between about 13 and about 18 GPa.

1 . A method of spinning a polyacrylonitrile PAN-based precursor fiber, comprising:
 extruding a spinning solution of polyacrylonitrile copolymer through a multi-filament spinnerette to produce a PAN-based precursor fiber, said polyacrylonitrile-based polymer having an average molecular weight of about 1,000,000 to about 2,000,000 daltons and said solution having a viscosity of between about 100 and about 300 Pa-sec (at a shear rate of 1 l/sec) at a dope extrusion temperature of between about 20° C. and about 26° C.;   maintaining an air gap between said spinnerette and a coagulation bath of between about 3 and about 10 mm;   stretching said PAN-based fiber in said air gap at a draw down ratio of between about 2.5 and about 8.5;   maintaining said coagulation bath between about 0° C. and about 5° C.; and   further stretching said PAN-based fiber in a series of stretch baths to produce a precursor PAN-based fiber having a diameter of between about 4 and about 10 micron, a tensile strength of between about 500 and about 1100 MPa, and an elastic modulus between about 13 and about 18 GPa.   
     
     
         2 . The method of  claim 1  including using a spinning solution including about 6 wt % polyacrylonitrile copolymer and a coagulation bath consisting of 60 wt % solution of solvent to deionized water. 
     
     
         3 . The method of  claim 2 , including using N,N-dimethylacetamide as said solvent. 
     
     
         4 . The method of  claim 1 , including subjecting said PAN-based fiber to a total draw down ratio of between about 15 and about 55. 
     
     
         5 . The method of  claim 1  including using a polyacrylonitrile-based copolymer having an average molecular weight of between 1,000,000 and 2,000,000 daltons. 
     
     
         6 . The method of  claim 1 , including maintaining a dope extrusion temperature of between about 22° C. to about 24° C. 
     
     
         7 . The method of  claim 1 , including extruding a spinning solution having a viscosity of between about 200 and about 250 Pa-sec. 
     
     
         8 . The method of  claim 1 , including stretching said PAN-based fiber in said air gap at a draw down ratio of between about 4.0 and about 8.5. 
     
     
         9 . The method of  claim 1 , including maintaining said coagulation bath at a temperature of between about 0° C. and about 3° C. 
     
     
         10 . The method of  claim 1 , including producing a precursor PAN-based fiber having a diameter of between about 5 and about 6 micron, a tensile strength of between about 800 and about 1100 MPa and an elastic modulus of between about 15 and about 18 GPa. 
     
     
         11 . The method of  claim 4 , including subjecting said PAN-based fiber to a total draw down ratio of between about 40 and about 55. 
     
     
         12 . A composition of matter, comprising a PAN-based precursor fiber having a diameter of between about 4 and about 10 microns, a tensile strength of between about 500 and about 1,100 MPa and an elastic modulus of between about 13 and about 18 GPa. 
     
     
         13 . The composition of matter of  claim 12  wherein said PAN-based precursor fiber has a diameter of between 5 and 6 microns. 
     
     
         14 . The composition of matter of  claim 12  wherein said PAN-based precursor fiber has a tensile strength of between 800 and 1,100 MPa. 
     
     
         15 . The composition of matter of  claim 12  wherein said PAN-based precursor fiber has an elastic modulus of between 15 and 18 GPa. 
     
     
         16 . The composition of matter of  claim 12  wherein said PAN-based precursor fiber has a diameter of between 5 and 6 microns, a tensile strength of between 800 and 1,100 MPa and an elastic modulus of between 15 and 18 GPa. 
     
     
         17 . The composition of matter of  claim 15 , wherein said PAN-based precursor fiber is in an unwindable, multifilament, continuous tow. 
     
     
         18 . The composition of matter of  claim 12 , wherein said PAN-based precursor fiber is in an unwindable, multifilament, continuous tow. 
     
     
         19 . The composition of matter of  claim 12 , made by extruding a spinning solution of polyacrylonitrile copolymer through a multi-filament spinnerette to produce a PAN-based precursor fiber, said polyacrylonitrile-based polymer having an average molecular weight of about 1,000,000 to about 2,000,000 daltons and said solution having a viscosity of between about 100 and about 300 Pa-sec (at a shear rate of 1 l/sec) at a dope extrusion temperature of between about 20° C. and about 26° C.;
 maintaining an air gap between said spinnerette and a coagulation bath of between about 3 and about 10 mm; 
 stretching said PAN-based fiber in said air gap at a draw down ratio of between about 2.5 and about 8.5; 
 maintaining said coagulation bath between about 0° C. and about 5° C.; and 
 further stretching said PAN-based fiber in a series of stretch baths to produce a precursor PAN-based fiber having a diameter of between about 4 and about 10 micron, a tensile strength of between about 500 and about 1100 MPa, and an elastic modulus between about 13 and about 18 GPa.