Insight into the ionic liquid tetraphenylphosphine salt on the processability improvement for PEEK

Abstract In this article, a high‐temperature resistant ionic liquid ([(Ph) 4 P] + [N(CF 3 SO 3 ) 2 ] − ) was introduced into PEEK to improve its processing performance. The effect of the IL on the rheology, crystalline, thermal, and mechanical properties of PEEK was analyzed. The rheological results show that the viscosity of PEEK decreases after adding IL, and the complex viscosity of PEEK decreases to 490 Pa s after adding 5 wt% IL, which is 15% lower than that of neat PEEK. Besides, it was found that adding a small amount of IL improved the crystallization ability of PEEK, shortened the crystallization time, and increased the tensile strength of PEEK blends. Additionally, IL has no significant effect on the molecular weight and degradation temperature of PEEK. In summary, adding IL into the PEEK matrix reduces the melt viscosity of PEEK, providing a reference for improving the processing fluidity of PEEK.