Abstract:

In order to develop the single yarn fabrics woven from pure staple warps of pre-oxidized polyacrylonitrile (POPAN) to avoid the defects of POPAN filament and blend fabrics, an operation for sizing pure POPAN staple yarns was proposed to improve their weavability for producing the fabrics. By using polyethylene oxide (PEO) as sizing agents, the effect of molecular weights on the sizing performances of pure POPAN staple warps was investigated. The relationship between PEO molecular weights and its paste viscosity, adhesion-to-fiber, film performances, desizing efficiency, and yarn properties such as the increase in tensile strength, loss in elongation, abrasion resistance, and decrease in hairiness of sized yarns was explored. The results showed that the properties of these sized yarns could be improved by increasing the molecular weights in the range considered. Based on the viscosity, adhesion, desizability, film performances, and properties of sized yarn, the PEO with the molecular weights range of 1.0×10⁵~1.5×10⁵ can be recommended for sizing pure POPAN staple single yarns before weaving process.

Key words: pre-oxidized polyacrylonitrile fiber, weavability, polyethylene oxide, molecular weight, sizing