PPS molecular chain is composed of benzene ring alternately connected by Para sulfur atoms. The molecular structure contains rigid and heat-resistant phenylene and flexible heat-resistant sulfide bonds, and the rigid structure of benzene ring is connected by flexible sulfide bonds. Therefore, the fiber has better heat resistance and thermal stability than conventional fibers. It has excellent strength, rigidity and fatigue resistance at high temperature. It can be used continuously at 200 ~ 240 ℃. It is relatively stable in air or nitrogen below 400 ℃ and basically has no weight loss. Its chemical corrosion resistance is similar to that of polytetrafluoroethylene (PTFE), which is known as the “king of plastics”. It can resist the corrosion of acid, alkali, chlorohydrocarbon, hydrocarbon, ketone, alcohol, vinegar and other chemicals. It is insoluble in any chemical solvent at 200 ℃. At the same time, it has excellent flame retardant performance and oxygen limiting index (LOI) is 34%, which can burn on the flame, but will not drip, and self extinguishes when leaving the fire. The smoke generation rate is lower than that of halogenated polymers.