METHOD OF PRODUCING A SPINNING SOLUTION FOR FORMING POLYOXADIAZOLE FIBER Russian patent published in 2019 - IPC D01F6/74 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry, specifically to production of polyoxadiazole fibrous materials used to obtain, for example, sorption-active materials. Technical result is achieved by the fact that in the method of producing a spinning solution consisting in loading first sulfuric acid, containing 17–65 wt% free anhydride, then 0.02–22.9 wt% of arylene-dicarboxylic acid, which is terephthalic acid with 0.004–0.017 wt% of paratoluilic acid, 3.1–27.4 wt% hydrazine sulphate with 0.05–34.0 wt% water and 0.05–21.8 wt meta-azobenzene dicarboxylic acid, heating the obtained solution while stirring continuously to 50–90 °C for 0.5–1.5 hours, holding at this temperature for 3–12 hours until obtaining 6–20 %-solution of oligomer, cooling it to 20–35 °C at rate of 0.5–5 °C/min, and then adding 2–89 % of sulfuric acid containing 17–65 wt% of sulfuric anhydride, and keeping for 3–5.5 hours with constant stirring to obtain 5.0–14.8 % solution of oligomer, then, while continuously stirring, polycondensation, while heating solution to 90-160 °C for 0.5–1.5 hours, holding at this temperature for 0.5-3 hours, then cooling to 60–120 °C and additional introduction of 3.4–94.2 wt% sulfuric acid with 6–8 wt% of water, while continuing to cool obtained solution to 20–35 °C with constant stirring for 3.5–5.5 h to produce spinning polymer solution in sulfuric acid with viscosity of 2,000–6,000 P, wherein polycondensation is carried out in a continuous manner with continuous dosing of sulfuric acid with 6–8 wt% of water into the spinning solution, then degassing in the continuous-action apparatus for 2–48 hours until the air content in solution is 1–6 ml/l, after which the spinning solution is fed for molding using a known method, wherein in 3.4–94.2 wt% sulfuric acid with 6–8 wt% additionally additive is added in amount of 2.5–5 wt%, which is an iron compound with technical carbon in ratio of 0.05 %÷99.95 %, wherein additive in acid is introduced in parts, first, 1/3 of the selected amount, and then rest with continuous stirring in two portions in equal portions while continuously stirring on an ultrasonic flow disperser at frequency of 24 kHz for 2.5–5.5 hours, while cooling the obtained solution while continuously stirring until obtaining spinning of 15–19 % solution of polymer in sulfuric acid with viscosity of 2,000–6,000 P.

EFFECT: improved processability of the molding process by maintaining dynamic viscosity while increasing concentration of the useful substance by adding an additive consisting of technical carbon and iron.

1 cl, 2 tbl, 1 ex