Rheology Modulation and Melt Strength Enhancement Enable Continuous Melt Spinning of PEK-C Fibers

Phenolphthalein poly (aryl ether ketone) (PEK-C) is highly compatible with the epoxy resin, which is applied in epoxy resin-based composites to improve its strength. Solu-tion spinning and electrospinning techniques are often used to produce the PEK-C fi-bers, but these techniques are polluting the environment and are not productive. To address the above challenges, melt spinning may be employed but since the high de-gree of molecular chain entanglement and poor melt fluidity of PEK-C, melt spinning remains difficult. Herein, this study presents a continuous melt spinning of PEK-C fi-bers through rheology modulation and melt strength enhancement. A series of PEK-C samples with different molecular weights were prepared by adjusting the molar ratio of monomers. The influence of molecular weights on rheological properties was inves-tigated by capillary rheology tests. The PEK-C with molecular weight (2.01×104 g/mol) was chosen and the optimal spinning temperature was determined to be 370 °C. The as-polymerized PEK-C powder was compounded into pellets, subsequently, the PEK-C pellets with the enhanced melt strength were continuously processed into fiber by melt spinning. The obtained PEK-C fibers possess high tensile strength 0.56 cN/dtex and breaking strength 1.06 cN/dtex, respectively. The mechanical properties and molecular chain orientation of PEK-C fibers were also optimized by spinning process parameters. This work presents continuous melt spinning of PEK-C fibers by rheology modulation and melt strength enhancement which resolve the environmental and low productive issues.