Abstract
The properties of the dope solution of acrylonitrile-methyl acrylate copolymer of 0.95 to 0.05 which was prepared by 50% aqueous solution of NaCNS were studied.
(1) The specific gravity of the dope was measured at 30°C in the concentration range from 0.63% to 11.93%.
(2) Hygroscopic behaviours of the 50% aqueous solution of NaCNS and the dope sulution with the polymer concentration of 9.5% were measured and compared at the relative humidity of 60% and at 25°C.
(3) Microscopic measurement was utilized to evaluate the dissolving rate of acrylonitrile fiber and polymer particle. The minimum concentration of NaCNS to dissolve the polymer is presumed to be around 46%.
(4) The viscosity of the dope solution was measured by the ball fall method in the polymer concentration range from 7% to 13%, and in the temperature range from 0.8°C to 65°C. At 30°C, the modified Baker equation obtained is as follows.
where η is the viscosity (sec.), M: molecular weight obtained by using the Staudinger equation, ηBP/C=1.5×10-4M (C: 0.5 mole/l), C: the polymer concentration of the dope (%).
(5) A linear relationship was observed between the logarithm of the viscosity and the recipr ocal of the absolute temperature in the temperature range from 30°C to 65°C. This relationship did not hold at the temperature below 10°C.
(6) The Copolymers of different molecular weights were mixed in various ratios to prepare six dope solutions of the copolymer mixture and the viscosity of the solutions were measured.
The relationship of the viscosity of each of the original polymer solution to those of the mixed polymer solutions may be expresed as: where η: the viscosity of the mixed polymer solution (sec.), η1: the viscosities of the original polymer solutions (sec.), W1: the weight fractions of the original polymer solutions (%).
