Effect of polyalphaolefin oils as a solvent in gel‐spinning of ultra‐high molecular weight polyethylene fibers

Abstract

AbstractIn this work, lubricants based on polyalphaolefin with different viscosities were evaluated in the processing of UHMWPE fibers. All fibers were obtained by extrusion with 0.04 to 60 wt% of polyalphaolefin oils with different kinematic viscosities and densities (in ascending order: PAO8, PAO40, and PAO100), under screw speed of 20 to 60 rpm with a nozzle of 1.82 mm diameter. Also, n‐hexane was used to extracting the oils from UHMWPE fibers. The fibers did not undergo the drawing process. It was observed that the fibers that underwent process with PAO40 showed the highest linear density, achieving 3273 tex, indicating the orientation of the crystals in a compact morphology inside the extruder and the higher relaxation after leaving the nozzle, increasing die‐swell. Microscopic analysis revealed roughness in fiber as the insertion of PAO100 oil increased, while fibers with PAO40 proved to be more densified. In addition, the fibers processed with PAO40 have an increase in thermal stability after n‐hexane extraction, with degradation temperature Tmax of 482°C in comparison with 476°C for the neat UHMWPE.