Modification method of heterocyclic aramid fiber spinning stock solution, modified heterocyclic aramid fiber spinning stock solution and application thereof

The invention discloses a modification method of a heterocyclic aramid fiber spinning stock solution, a modified heterocyclic aramid fiber spinning stock solution and an application thereof, and relates to the technical field of heterocyclic aramid fiber preparation. A spinning auxiliary agent is added into a polymer solution (namely a heterocyclic aramid fiber spinning stock solution) obtained after condensation polymerization of p-phenylenediamine, terephthaloyl and heterocyclic diamine for blending, so that the surface tension of the heterocyclic aramid fiber spinning stock solution is remarkably reduced under the condition that a polymerization process and a dissolution process are not changed; and meanwhile, the viscosity of the heterocyclic aramid fiber spinning stock solution is improved, so that the spinning stock solution (namely the modified heterocyclic aramid fiber spinning stock solution) with low surface tension and high viscosity is obtained. The spinning stock solution with low surface tension