0samps 15 00 c polymerization conditions copolymer type a btemperature u00b0 c 67 u00b0 52 u00b0 duration hours 11 13aibn catalyst azobisisobutyronitrile 0 027 0 2malic acid stabilizer 0 015 paratoluene zinc sulphonatestabilizer 0 1 d characteristics of the mixture obtained at the end of thepolymerization copolymer type a bsolids 21 0 19 1monomers conversion topolymer 65 6 42 4conversion of samps topolymer 65 6 e composition and molecular weight of the polymers copolymer type a bacn by weight 85 00 55 00 in mols 96 07 69 09samps by weight 15 00 in mols 3 93 ch ccl sub 2 by weight 45 00 in mols 30 91 f characteristics of the viscous spinning dopes solids 22 5 22 5dmf 77 5 77 5______________________________________ the final viscous spinning solution is obtained by mixing 20 parts of the solution of polymer a and 80 parts of the solution of polymer b in one of the known static or dynamic mixers used for high viscosity polymeric solutions the fibre obtained by spinning said solution has the same composition by weight and by monomeric units as that obtained from the ternary copolymer of example 5 viz ______________________________________acn 61 by weight 74 96 by molsch sub 2 ccl sub 2 36 by weight 24 19 by molssamps 3 by weight 0 85 by mols______________________________________ ______________________________________count dtex 3 2tenacity g dtex 2 7elongation.